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Peer SM, Desai M, Bukhari S, Delores Y, Jonas R, Sinha P. Real-Time Detection of Circulating Thrombi in an Extracorporeal Circuit Using Doppler Ultrasound: In-Vitro Proof of Concept Study. World J Pediatr Congenit Heart Surg 2024; 15:446-452. [PMID: 38291667 DOI: 10.1177/21501351231221543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
BACKGROUND Thromboembolic stroke continues to be by far the most common severe adverse event in patients supported with mechanical circulatory assist devices. Feasibility of using Doppler ultrasound to detect circulating thrombi in an extracorporeal circuit was investigated. METHODS A mock extracorporeal circulatory loop of uncoated cardiopulmonary bypass tubing and a roller pump was setup. A Doppler bubble counter was used to monitor the mean ultrasound backscatter signal (MUBS). The study involved two sets of experiments. In Scenario 1, the circuit was sequentially primed with human blood components, and the MUBS was measured. In Scenario 2, the circuit was primed with heparinized fresh porcine blood, and the MUBS was measured. Fresh blood clots (diameter <1,000 microns, 1,000-5,000 microns, >5,000 microns) were injected into the circuit followed by protamine administration. RESULTS In Scenario 1 (n = 3), human platelets produced a baseline MUBS of 1.5 to 3.5 volts/s. Addition of packed human red blood cells increased the baseline backscatter to 17 to 21 volts/s. Addition of fresh frozen plasma did not change the baseline backscatter. In Scenario 2 (n = 5), the blood-primed circuit produced a steady baseline MUBS. Injection of the clots resulted in abrupt and transient increase (range: 3-30 volts/s) of the baseline MUBS. Protamine administration resulted in a sustained increase of MUBS followed by circuit thrombosis. CONCLUSIONS Doppler ultrasound may be used for real-time detection of circulating solid microemboli in the extracorporeal circuit. This technology could potentially be used to design safety systems that can reduce the risk of thromboembolic stroke associated with mechanical circulatory support therapy.
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Affiliation(s)
- Syed Murfad Peer
- Department of Pediatric Cardiac Surgery, University of Minnesota Masonic Children's Hospital, Minneapolis, MN, USA
| | - Manan Desai
- Department of Cardiovascular Surgery, Children's National Hospital, Washington, DC, USA
| | - Syed Bukhari
- Department of Cardiovascular Surgery, Children's National Hospital, Washington, DC, USA
| | - Yunchuan Delores
- Department of Laboratory Medicine and Hematology, Children's National Hospital, Washington, DC, USA
| | - Richard Jonas
- Department of Cardiovascular Surgery, Children's National Hospital, Washington, DC, USA
| | - Pranava Sinha
- Department of Pediatric Cardiac Surgery, University of Minnesota Masonic Children's Hospital, Minneapolis, MN, USA
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Keunen RWM, Daal SM, Romers GJ, Hoohenkerk GJF, van Kampen PM, Suyker WJL. Diagnostic Accuracy of an Algorithm for Discriminating Presumed Solid and Gaseous Microembolic Signals During Transcranial Doppler Examinations. ULTRASOUND IN MEDICINE & BIOLOGY 2023; 49:2483-2488. [PMID: 37709563 DOI: 10.1016/j.ultrasmedbio.2023.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/09/2023] [Accepted: 08/10/2023] [Indexed: 09/16/2023]
Abstract
OBJECTIVE The aim of the work described here was to assess the diagnostic accuracy of a new algorithm (SGA-a) for time-domain analysis of transcranial Doppler audio signals to discriminate presumed solid and gaseous microembolic signals and artifacts (SGAs). METHODS SGA-a was validated by human experts in an artifact cohort of 20 patients subjected to a 1-h transcranial Doppler exam before cardiac surgery (cohort 1). Emboli were validated in a cohort of 10 patients after aortic valve replacement in a 4-h monitoring period (cohort 2). The SGA misclassification rate was estimated by testing SGA-a on artifact-free test files of solid and gaseous emboli. RESULTS In cohort 1 (n = 24,429), artifacts were classified with an accuracy of 94.5%. In cohort 2 (n = 12,328), the accuracy in discriminating solid/gaseous emboli from artifacts was 85.6%. The 95% limits of agreement for, respectively, the numbers of presumed solids and gaseous emboli, artifacts and microembolic signals of undetermined origin were [-10, 10], [-14, 7] and [-9, 16], and the intra-class correction coefficients were 0.99, 0.99 and 0.99, respectively. The rate of misclassification of solid test files was 2%, and the rate of misclassification of gaseous test files was 12%. CONCLUSION SGA-a can detect presumed solid and gaseous microembolic signals and differentiate them from artifacts. SGA-a could be of value when both solid and gaseous emboli may jeopardize brain function such as seen during cardiac valve and/or aortic arch replacement procedures.
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Affiliation(s)
- Rudolf W M Keunen
- Department of Cardiac Surgery, Haga Teaching Hospitals, The Hague, The Netherlands.
| | - Sayonara M Daal
- Department of Cardiac Surgery, Haga Teaching Hospitals, The Hague, The Netherlands
| | | | | | | | - Willem J L Suyker
- Department of Cardiothoracic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
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3
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Christoph M, Poitz D, Pfluecke C, Forkmann M, Huo Y, Gaspar T, Schoen S, Ibrahim K, Quick S, Wunderlich C. Simple periprocedural precautions to reduce Doppler microembolic signals during AF ablation. J Interv Card Electrophysiol 2022; 64:359-365. [PMID: 34060007 PMCID: PMC9399063 DOI: 10.1007/s10840-021-01010-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 05/12/2021] [Indexed: 11/25/2022]
Abstract
BACKGROUND Doppler microembolic signals (MES) occur during atrial fibrillation ablation despite of permanent flushed transseptal sheaths, frequent controls of periprocedural coagulation status and the use of irrigated ablation catheters PURPOSE: To investigate the number and type of MES depending on the procedure time, prespecified procedure steps, the activated clotting time (ACT) during the ablation procedure and the catheter contact force. METHODS In a prospective trial, 53 consecutive atrial fibrillation patients underwent pulmonary vein isolation by super-irrigated "point-by-point" ablation. All patients underwent a periinterventional, continuous transcranial Doppler examination (TCD) of the bilateral middle cerebral arteries during the complete ablation procedure. RESULTS An average of 686±226 microembolic signals were detected by permanent transcranial Doppler. Thereby, 569±208 signals were differentiated as gaseous and 117±31 as solid MES. The number of MES with regard to defined procedure steps were as follows: gaseous: [transseptal puncture, 26 ± 28; sheath flushing, 24±12; catheter change, 21±11; angiography, 101±28; mapping, 9±9; ablation, 439±192; protamine administration, 0±0]; solid: [transseptal puncture, 8±8; sheath flushing, 9±5; catheter replacement, 6±6; angiography, not measurable; mapping, 2±5; ablation, 41±22; protamine administration, 0±0]. Significantly less MES occurred with shorter procedure time, higher ACT and the use of tissue contact force monitoring. CONCLUSION The current study demonstrates that during atrial fibrillation ablation using irrigated, "point-by-point" RF ablation, masses of microembolic signals are detected in transcranial ultrasound especially in the period of RF current application. The number of MES depends on the total procedure time and the reached ACT during ablation. The use of contact force monitoring might reduce MES during RF ablation.
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Affiliation(s)
- Marian Christoph
- Technische Universität Dresden, Campus Chemnitz, Klinikum Chemnitz, Flemmingstrasse 2, 09116, Chemnitz, Germany.
| | - David Poitz
- Technische Universität Dresden, Heart Center Dresden, Fetscherstrasse 76, 01307, Dresden, Germany
| | - Christian Pfluecke
- Technische Universität Dresden, Heart Center Dresden, Fetscherstrasse 76, 01307, Dresden, Germany
| | - Mathias Forkmann
- Klinikum Coburg, Ketschendorfer Strasse 33, 96450, Coburg, Germany
| | - Yan Huo
- Technische Universität Dresden, Heart Center Dresden, Fetscherstrasse 76, 01307, Dresden, Germany
| | - Thomas Gaspar
- Technische Universität Dresden, Heart Center Dresden, Fetscherstrasse 76, 01307, Dresden, Germany
| | - Steffen Schoen
- Technische Universität Dresden, Klinikum Pirna, Struppener Strasse 13, 01796, Pirna, Germany
| | - Karim Ibrahim
- Technische Universität Dresden, Campus Chemnitz, Klinikum Chemnitz, Flemmingstrasse 2, 09116, Chemnitz, Germany
| | - Silvio Quick
- Technische Universität Dresden, Campus Chemnitz, Klinikum Chemnitz, Flemmingstrasse 2, 09116, Chemnitz, Germany
| | - Carsten Wunderlich
- Technische Universität Dresden, Klinikum Pirna, Struppener Strasse 13, 01796, Pirna, Germany
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Kietaibl C, Horvat Menih I, Engel A, Ullrich R, Klein KU, Erdoes G. Cerebral microemboli during extracorporeal life support: a single-centre cohort study. Eur J Cardiothorac Surg 2021; 61:172-179. [PMID: 34406372 DOI: 10.1093/ejcts/ezab353] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 06/10/2021] [Accepted: 06/22/2021] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES The aim of this study was to investigate the load and composition of cerebral microemboli in adult patients undergoing venoarterial extracorporeal life support (ECLS). METHODS Adult ECLS patients were investigated for the presence of cerebral microemboli and compared to critically ill, pressure-controlled ventilated controls and healthy volunteers. Cerebral microemboli were detected in both middle cerebral arteries for 30 min using transcranial Doppler ultrasound. Neurological outcome (ischaemic stroke, global brain ischaemia, intracerebral haemorrhage, seizure, metabolic encephalopathy, sensorimotor sequelae and neuropsychiatric disorders) was additionally evaluated. RESULTS Twenty ECLS patients (cannulations: 15 femoro-femoral, 4 femoro-subclavian, 1 femoro-aortic), 20 critically ill controls and 20 healthy volunteers were analysed. ECLS patients had statistically significantly more cerebral microemboli than critically ill controls {123 (43-547) [median (interquartile range)] vs 35 (16-74), difference: 88 [95% confidence interval (CI) 19-320], P = 0.023} and healthy volunteers [11 (5-12), difference: 112 (95% CI 45-351), P < 0.0001]. In ECLS patients, 96.5% (7346/7613) of cerebral microemboli were of gaseous composition, while solid cerebral microemboli [1 (0-5)] were detected in 12 out of 20 patients. ECLS patients had more neurological complications than critically ill controls (12/20 vs 3/20, P = 0.003). In ECLS patients, a high microembolic rate (>100/30 min) tended to be associated with neurological complications including ischaemic stroke, neuropsychiatric disorders, sensorimotor sequelae and non-convulsive status epilepticus (odds ratio 4.5, 95% CI 0.46-66.62; P = 0.559). CONCLUSIONS Our results indicate that adult ECLS patients are continuously exposed to many gaseous and, frequently, to few solid cerebral microemboli. Prolonged cerebral microemboli formation may contribute to neurological morbidity related to ECLS treatment. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, NCT02020759, https://clinicaltrials.gov/ct2/show/NCT02020759?term=erdoes&rank=1.
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Affiliation(s)
- Clemens Kietaibl
- Department of Anaesthesia, Critical Care and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Ines Horvat Menih
- Department of Anaesthesia, Critical Care and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Adrian Engel
- Department of Anaesthesia, Critical Care and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Roman Ullrich
- Department of Anaesthesia, Critical Care and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Klaus U Klein
- Department of Anaesthesia, Critical Care and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Gabor Erdoes
- Department of Anaesthesiology and Pain Medicine, Bern University Hospital, University of Bern, Bern, Switzerland
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5
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Jabur GN, Donnelly J, Merry AF, Mitchell SJ. A prospective observational study of emboli exposure in open versus closed chamber cardiac surgery. Perfusion 2021; 37:715-721. [PMID: 34112049 DOI: 10.1177/02676591211023897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Exposure to cerebral emboli is ubiquitous and may be harmful in cardiac surgery utilizing cardiopulmonary bypass. This was a prospective observational study aiming to compare emboli exposure in closed-chamber with open-chamber cardiac surgery, distinguish particulate from gaseous emboli and examine cerebral laterality in distribution. METHODS Forty patients underwent either closed-chamber procedures (n = 20) or open-chamber procedures (n = 20). Emboli (gaseous and solid) were detected using transcranial Doppler in both middle cerebral arteries in two monitoring phases: 1, initiation of bypass to the removal of the aortic cross-clamp; and 2, removal of aortic cross-clamp to 20 minutes after venous decannulation. RESULTS Total (median (interquartile range)) emboli counts (both phases) were 898 (499-1366) and 2617 (1007-5847) in closed-chamber and open-chamber surgeries, respectively. The vast majority were gaseous; median 794 (closed-chamber surgery) and 2240 (open-chamber surgery). When normalized for duration, there was no difference between emboli exposures in closed-chamber and open-chamber surgery in phase 1: 6.8 (3.6-15.2) versus 6.4 (2.0-18.1) emboli per minute, respectively. In phase 2, closed-chamber surgery cases were exposed to markedly fewer emboli than open-chamber surgery cases: 9.6 (5.1-14.9) versus 43.3 (19.7-60.3) emboli per minute, respectively. More emboli (total) passed into the right cerebral circulation: 985 (397-2422) right versus 376 (198-769) left. CONCLUSIONS Patients undergoing open-chamber surgery are exposed to considerably higher numbers of cerebral arterial emboli after removal of the aortic cross-clamp than those undergoing closed-chamber surgery, and more emboli enter the right middle cerebral artery than the left. These results may help inform the evaluation of the pathophysiological impact of emboli exposure.
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Affiliation(s)
- Ghazwan Ns Jabur
- Department of Clinical Perfusion, Auckland City Hospital, Auckland, New Zealand.,Department of Anesthesiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Joseph Donnelly
- Department of Anesthesiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Alan F Merry
- Department of Anesthesiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.,Department of Anesthesia, Auckland City Hospital, Auckland, New Zealand
| | - Simon J Mitchell
- Department of Anesthesiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.,Department of Anesthesia, Auckland City Hospital, Auckland, New Zealand
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6
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Kussman BD, Imaduddin SM, Gharedaghi MH, Heldt T, LaRovere K. Cerebral Emboli Monitoring Using Transcranial Doppler Ultrasonography in Adults and Children: A Review of the Current Technology and Clinical Applications in the Perioperative and Intensive Care Setting. Anesth Analg 2021; 133:379-392. [PMID: 33764341 DOI: 10.1213/ane.0000000000005417] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Transcranial Doppler (TCD) ultrasonography is the only noninvasive bedside technology for the detection and monitoring of cerebral embolism. TCD may identify patients at risk of acute and chronic neurologic injury from gaseous or solid emboli. Importantly, a window of opportunity for intervention-to eliminate the source of the emboli and thereby prevent subsequent development of a clinical or subclinical stroke-may be identified using TCD. In this review, we discuss the application of TCD sonography in the perioperative and intensive care setting in adults and children known to be at increased risk of cerebral embolism. The major challenge for evaluation of emboli, especially in children, is the need to establish the ground truth and define true emboli identified by TCD. This requires the development and validation of a predictive TCD emboli monitoring technique so that appropriately designed clinical studies intended to identify specific modifiable factors and develop potential strategies to reduce pathologic cerebral embolic burden can be performed.
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Affiliation(s)
- Barry D Kussman
- From the Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts.,Department of Anaesthesia, Harvard Medical School, Boston, Massachusetts
| | - Syed M Imaduddin
- Department of Electrical Engineering and Computer Science, the Institute for Medical Engineering and Science, and the Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Mohammad Hadi Gharedaghi
- From the Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts.,Department of Anaesthesia, Harvard Medical School, Boston, Massachusetts
| | - Thomas Heldt
- Department of Electrical Engineering and Computer Science, the Institute for Medical Engineering and Science, and the Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Kerri LaRovere
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts.,Department of Neurology, Harvard Medical School, Boston, Massachusetts
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7
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Intraoperatives Monitoring in der konventionellen und endovaskulären Aortenchirurgie – Neue Verfahren. GEFÄSSCHIRURGIE 2019. [DOI: 10.1007/s00772-019-00562-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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8
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Cerebral embolic protection in thoracic endovascular aortic repair. J Vasc Surg 2018; 68:1656-1666. [DOI: 10.1016/j.jvs.2017.11.098] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 11/27/2017] [Indexed: 01/14/2023]
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9
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Aggarwal SK, Delahunty RN N, Menezes LJ, Perry R, Wong B, Reinthaler M, Ozkor M, Mullen MJ. Patterns of solid particle embolization during transcatheter aortic valve implantation and correlation with aortic valve calcification. J Interv Cardiol 2018; 31:648-654. [DOI: 10.1111/joic.12526] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 04/28/2018] [Accepted: 05/15/2018] [Indexed: 11/28/2022] Open
Affiliation(s)
- Suneil K. Aggarwal
- Department of Cardiology; The Heart Hospital; University College London Hospitals; London UK
| | - Nicola Delahunty RN
- Department of Cardiology; The Heart Hospital; University College London Hospitals; London UK
| | - Leon J. Menezes
- Department of Nuclear Medicine; University College London Hospitals; London UK
| | - Richard Perry
- National Hospital for Neurology & Neurosurgery; University College London Hospitals; London UK
| | - Bethany Wong
- Department of Cardiology; The Heart Hospital; University College London Hospitals; London UK
| | - Markus Reinthaler
- Department of Cardiology; The Heart Hospital; University College London Hospitals; London UK
| | - Muhiddin Ozkor
- Department of Cardiology; The Heart Hospital; University College London Hospitals; London UK
| | - Michael J. Mullen
- Department of Cardiology; The Heart Hospital; University College London Hospitals; London UK
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10
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Cerebral Gaseous Microemboli are Detectable During Continuous Venovenous Hemodialysis in Critically Ill Patients: An Observational Pilot Study. J Neurosurg Anesthesiol 2018; 29:236-242. [PMID: 26998647 DOI: 10.1097/ana.0000000000000296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Continuous venovenous hemodialysis (CVVHD) may generate microemboli that cross the pulmonary circulation and reach the brain. The aim of the present study was to quantify (load per time interval) and qualify (gaseous vs. solid) cerebral microemboli (CME), detected as high-intensity transient signals, using transcranial Doppler ultrasound. MATERIALS AND METHODS Twenty intensive care unit (ICU group) patients requiring CVVHD were examined. CME were recorded in both middle cerebral arteries for 30 minutes during CVVHD and a CVVHD-free interval. Twenty additional patients, hospitalized for orthopedic surgery, served as a non-ICU control group. Statistical analyses were performed using the Mann-Whitney U test or the Wilcoxon matched-pairs signed-rank test, followed by Bonferroni corrections for multiple comparisons. RESULTS In the non-ICU group, 48 (14.5-169.5) (median [range]) gaseous CME were detected. In the ICU group, the 67.5 (14.5-588.5) gaseous CME detected during the CVVHD-free interval increased 5-fold to 344.5 (59-1019) during CVVHD (P<0.001). The number of solid CME was low in all groups (non-ICU group: 2 [0-5.5]; ICU group CVVHD-free interval: 1.5 [0-14.25]; ICU group during CVVHD: 7 [3-27.75]). CONCLUSIONS This observational pilot study shows that CVVHD was associated with a higher gaseous but not solid CME burden in critically ill patients. Although the differentiation between gaseous and solid CME remains challenging, our finding may support the hypothesis of microbubble generation in the CVVHD circuit and its transpulmonary translocation toward the intracranial circulation. Importantly, the impact of gaseous and solid CME generated during CVVHD on brain integrity of critically ill patients currently remains unknown and is highly debated.
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Ferroudji K, Benoudjit N, Bouakaz A. An automated microemboli detection and classification system using backscatter RF signals and differential evolution. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2017; 40:85-99. [PMID: 28070749 DOI: 10.1007/s13246-016-0512-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 11/28/2016] [Indexed: 01/20/2023]
Abstract
Embolic phenomena, whether air or particulate emboli, can induce immediate damages like heart attack or ischemic stroke. Embolus composition (gaseous or particulate matter) is vital in predicting clinically significant complications. Embolus detection using Doppler methods have shown their limits to differentiate solid and gaseous embolus. Radio-frequency (RF) ultrasound signals backscattered by the emboli contain additional information on the embolus in comparison to the traditionally used Doppler signals. Gaseous bubbles show a nonlinear behavior under specific conditions of the ultrasound excitation wave, this nonlinear behavior is exploited to differentiate solid from gaseous microemboli. In order to verify the usefulness of RF ultrasound signal processing in the detection and classification of microemboli, an in vitro set-up is developed. Sonovue micro bubbles are exploited to mimic the acoustic behavior of gaseous emboli. They are injected at two different concentrations (0.025 and 0.05 µl/ml) in a nonrecirculating flow phantom containing a tube of 0.8 mm in diameter. The tissue mimicking material surrounding the tube is chosen to imitate the acoustic behavior of solid emboli. Both gaseous and solid emboli are imaged using an Anthares ultrasound scanner with a probe emitting at a transmit frequency of 1.82 MHz and at two mechanical indices (MI) 0.2 and 0.6. We propose in this experimental study to exploit discrete wavelet transform and a dimensionality reduction algorithm based on differential evolution technique in the analysis and the characterization of the backscattered RF ultrasound signals from the emboli. Several features are evaluated from the detail coefficients. It should be noted that the features used in this study are the same used in the paper by Aydin et al. These all features are used as inputs to the classification models without using feature selection method. Then we perform feature selection using differential evolution algorithm with support vector machines classifier. The experimental results show clearly that our proposed method achieves better average classification rates compared to the results obtained in a previous study using also the same backscatter RF signals.
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Affiliation(s)
- Karim Ferroudji
- Laboratoire d'Automatique Avancée et d'Analyse des Systèmes (LAAAS), Université de Batna-2, Fesdis, Algeria.
| | - Nabil Benoudjit
- Laboratoire d'Automatique Avancée et d'Analyse des Systèmes (LAAAS), Université de Batna-2, Fesdis, Algeria
| | - Ayache Bouakaz
- UMR Inserm U930-Imagerie et cerveau, Université François Rabelais de Tours, Tours, France
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12
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Jurga J, Tornvall P, Dey L, van der Linden J, Sarkar N, von Euler M. Does Coronary Angiography and Percutaneous Coronary Intervention Affect Cognitive Function? Am J Cardiol 2016; 118:1437-1441. [PMID: 27634030 DOI: 10.1016/j.amjcard.2016.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 08/02/2016] [Accepted: 08/02/2016] [Indexed: 11/18/2022]
Abstract
Cerebral microemboli are frequently observed during coronary angiography (CA) and percutaneous coronary intervention (PCI), and their numbers have been related to the vascular access site used. Although cerebral microemboli can cause silent cerebral lesions, their clinical impact is debated. To study this, 93 patients referred for CA or PCI underwent serial cognitive testing using the Montreal Cognitive Assessment (MoCA) test to detect postprocedural cognitive impairment. Patients were randomized to radial or femoral access. In a subgroup of 35 patients, the number of cerebral microemboli was monitored with transcranial Doppler technique. We found the median precatheterization result of the MoCA test to be 27, and it did not change significantly 4 and 31 days, respectively, after the procedure. There was no significant correlation between the number of cerebral microemboli and the difference between preprocedural and postprocedural MoCA tests. The test results did not differ between vascular access sites. One-third of the patients had a precatheterization median MoCA test result <26 corresponding to mild cognitive impairment. In conclusion, using the MoCA test, we could not detect any cognitive impairment after CA or PCI, and no significant correlations were found between the results of the MoCA test and cerebral microemboli or vascular access site, respectively. In patients with suspected coronary heart disease, mild cognitive impairment was common.
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Affiliation(s)
- Juliane Jurga
- Unit of Cardiology, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden; Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden
| | - Per Tornvall
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
| | - Linda Dey
- Unit of Cardiology, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden; Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden
| | - Jan van der Linden
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Nondita Sarkar
- Unit of Cardiology, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden; Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden
| | - Mia von Euler
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden; Karolinska Institutet Stroke Research Network at Södersjukhuset, Stockholm, Sweden.
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13
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Stark P, Kalkbrenner C, Braß P, Brucher R. Artificial blood circulatory and special Ultrasound Doppler probes for detecting and sizing gaseous embolism. CURRENT DIRECTIONS IN BIOMEDICAL ENGINEERING 2016. [DOI: 10.1515/cdbme-2016-0062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
This paper presents a special designed artificial blood circulatory (ABC) for studying gaseous embolism based on detection of gaseous emboli and their sizing using ultrasound (US) spectral Doppler. Blood mimicking fluid (BMF) was used in the circulatory to get valid results without using human blood. The additional necessary degassing circulatory shows a promising effect of decontaminating the BMF from air bubbles. This offers the base for detecting and sizing microemboli using special algorithms and finally leads to reliable calculations of dangerous embolism and its air volume. Standard US probes at an integrated tissue model and a new 8-MHz central catheter ultrasound (CCUS) probe inside a superior vena cava model (SVCM) are used and deliver the Doppler spectrogram as input for automatic emboli detection and further signal analysis. First results using the newly developed 8-MHz CCUS probe inside the SVCM and its Doppler spectrogram characteristics show promising results but need more detailed studies.
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Affiliation(s)
- Philipp Stark
- Faculty of Medical Engineering, Hochschule Ulm, University of Applied Sciences, Prittwitzstraße 10, 89075 Ulm, Germany
| | - Christoph Kalkbrenner
- Faculty of Medical Engineering, Hochschule Ulm, University of Applied Sciences, Prittwitzstraße 10, 89075 Ulm, Germany
| | - Patrick Braß
- Helios Klinikum, Krefeld Klinik für Anästhesie Intensivmedizin und Schmerztherapie, Lutherplatz 1, 47800 Krefeld, Germany
| | - Rainer Brucher
- Faculty of Medical Engineering, Hochschule Ulm, University of Applied Sciences, Prittwitzstraße 10, 89075 Ulm, Germany
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14
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Abstract
Despite an overall decrease in perioperative morbidity and mortality, evidence of some degree of central nervous system dysfunction associated with coronary artery bypass graft (CABG) surgery—with or without cardiopulmonary bypass— has steadily mounted. From preoperative studies of CABG patients, it is apparent that over 50% of patients who present for cardiac surgery have evidence of either extracranial or intracranial atherosclerotic disease. Patient-specific factors thus have a fundamental impact on the risks of a brain injury developing after CABG surgery. Cerebral embolization and/or ischemic hypoperfusion are the most likely etiologic mechanisms for perioperative brain injury associated with cardiac surgery, and these factors are closely interrelated. Various monitoring techniques can decrease risk of intraoperative cerebral embolization and hypoperfusion and are associated with improved outcomes. Ultrasound guided aortic instrumentation (epiaortic scanning) can markedly decrease atheroembolic load and risk of stroke. Unrecognized sources of microgaseous emboli, including air entrainment from surgical purse string sutures and perfusionist interventions, can be identified and reduced by transcranial Doppler monitoring. Cerebral hypoperfusion from unrecognized cerebral venous obstruction, inadequate mean arterial pressure, or from hypocapnic cerebral alkalosis can be identified by multimodality neuromonitoring using regional cerebral oxygen saturation and transcranial Doppler. Overall patient outcomes can be improved, and hospital length of stay shortened, by applied neuromonitoring techniques.
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Affiliation(s)
- John M Murkin
- University of Western Ontario, London, Ontario, Canada.
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15
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Saidi N, Murkin JM. Applied Neuromonitoring in Cardiac Surgery: Patient Specific Management. Semin Cardiothorac Vasc Anesth 2016; 9:17-23. [PMID: 15735841 DOI: 10.1177/108925320500900103] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Various studies have demonstrated that over 50% of patients presenting for coronary revascularization surgery have evidence of extracranial or intracranial atherosclerotic disease. Although evidence is compelling that cerebral emboli are a major cause of perioperative central nervous system (CNS) morbidity in such patients, it is also apparent that alterations in cerebral perfusion pressure and blood flow can profoundly influence the extent of injury after an embolic insult. In this context, the recent studies demonstrating improved CNS outcomes with applied neuromonitoring in cardiac surgical patients can be understood as reflecting the optimization of CNS perfusion characteristics with potential amelioration of microembolic injury. This review critically evaluates and discusses the relevant characteristics of applied neuromonitoring techniques, including bispectral index (BIS), transcranial Doppler (TCD), and near infrared reflectance spectroscopy (NIRS) in the context of patients undergoing cardiac surgical procedures. Recent outcomes data regarding CNS and related morbidity and the influence of neuromonitoring in these groups are evaluated.
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Affiliation(s)
- Nousheh Saidi
- Department of Anesthesiology and Perioperative Medicine (Clinical Fellow), University of Western Ontario, London, Ontario
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16
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Doblar DD. Intraoperative Transcranial Ultrasonic Monitoring for Cardiac and Vascular Surgery. Semin Cardiothorac Vasc Anesth 2016; 8:127-45. [PMID: 15247999 DOI: 10.1177/108925320400800206] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The brain is the only organ not routinely monitored by any direct method during the administration of anesthesia. Anesthesiologists rely primarily on indirect physiologic evidence provided by blood pressure, peripheral pulse oximetry, heart rate, and respiratory and anesthetic gas concentrations to determine that brain blood flow and oxygenation are adequate. The reasons for this practice are that: (1) after millions of anesthetics significant numbers of adverse neurologic outcomes have not occurred, (2) the interpretation of transcranial Doppler, electroencephalogram, and near-infrared cerebral oximetry requires experienced personnel, and (3) the evidence of cost-benefit to support monitoring is limited. Brain monitoring generally has been confined to procedures where the brain is exposed to unique insults and risks specific to the procedures and where reliance on indirect physiologic evidence of cerebral integrity has been proven to be unreliable. Transcranial Doppler monitoring is valuable in the assessment of established surgical techniques, refinement of recent surgical techniques, and development of new techniques and instrumentation. Brain monitoring with transcranial Doppler is of particular value when deviations from established surgical or anesthetic techniques may place the brain at risk for cerebral hyper-or hypoperfusion, gaseous or particulate embolization, or their combined effects. This paper discusses applications of transcranial Doppler in coronary artery bypass surgery, aortic arch procedures, pediatric cardiac surgery, carotid endarterectomy, and a few other special cases. The insight into cerebral physiology is unique to the continuous window on the brain that transcranial Doppler provides.
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Affiliation(s)
- Dennis D Doblar
- Department of Anesthesiology, The University of Alabama, Birmingham, Alabama 35249-6810, USA.
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17
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Wallace S, Døhlen G, Holmstrøm H, Lund C, Russell D. Cerebral Microemboli Detection and Differentiation During Transcatheter Closure of Patent Ductus Arteriosus. Pediatr Cardiol 2016; 37:1141-7. [PMID: 27229332 DOI: 10.1007/s00246-016-1410-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 05/17/2016] [Indexed: 10/21/2022]
Abstract
The aim of this prospective study was to determine the frequency and composition of cerebral microemboli in a pediatric population, during transcatheter closure of patent ductus arteriosus (PDA). Multifrequency transcranial Doppler was used to monitor cerebral blood flow velocity (CBFV) and detect microembolic signals (MES) in the middle cerebral artery in 23 patients (median age 18 months). MES were automatically identified and differentiated according to composition; gaseous or solid. The procedure was divided into five periods: Arterial catheterization; venous catheterization; ductal catheterization; angiography; device placement and release. Timing of catheter manipulations and MES were registered and compared. MES were detected in all patients. The median number of signals was 7, (minimum 1, maximum 28). Over 95 % of all MES were gaseous. 11 % were detected during device placement while 64 % were detected during angiographic studies, significantly higher than during any other period (P < 0.001). There was a moderate correlation between the number of MES and volume of contrast used, (R = 0.622, P < 0.01). There was no correlation with fluoroscopic time or duration of procedure. This is the first study to investigate the timing and composition of cerebral microemboli during PDA occlusion. Microemboli were related to specific catheter manipulations and correlated with the amount of contrast used.
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Affiliation(s)
- Sean Wallace
- Department of Paediatric Cardiology, Rikshospitalet, Oslo, Norway.
| | - Gaute Døhlen
- Department of Paediatric Cardiology, Rikshospitalet, Oslo, Norway
| | - Henrik Holmstrøm
- Department of Paediatric Cardiology, Rikshospitalet, Oslo, Norway
| | | | - David Russell
- Department of Neurology, Rikshospitalet, Oslo, Norway
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18
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Hillebrand J, Rouhollahpour A, Zierer A, Moritz A, Martens S. Digital Carotid Compression: A Simple Method to Reduce Solid Cerebral Emboli During Cardiac Surgery. J Cardiothorac Vasc Anesth 2016; 30:304-8. [DOI: 10.1053/j.jvca.2015.11.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Indexed: 11/11/2022]
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19
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Cerebral microemboli detection and differentiation during transcatheter closure of atrial septal defect in a paediatric population. Cardiol Young 2015; 25:237-44. [PMID: 24522121 DOI: 10.1017/s1047951113002072] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
INTRODUCTION The aim of this prospective study was to determine the frequency and composition of cerebral microemboli in a paediatric population during transcatheter atrial septal defect closure. METHODS Multi-frequency transcranial Doppler was used to detect microembolic signals in the middle cerebral artery of 24 patients. Embolic signals were automatically identified and differentiated according to their composition, gaseous or solid. The procedure was divided into five periods: right cardiac catheterisation; left cardiac catheterisation; pulmonary angiography; balloon sizing; and device placement. RESULTS Microemboli were detected in all patients. The median number of signals was 63 and over 95% gaseous. The total number of microembolic signals detected during two periods - balloon sizing and sheath placement and device placement - was not significantly different (median: 18 and 25, respectively) but was significantly higher than each of the other three periods (p<0.001). In eight patients, the device was opened more than once and the number of embolic signals decreased with each successive device deployment. There was no correlation between the number of microembolic signals and fluoroscopic time, duration of procedure, age, or device size. CONCLUSION This is the first study to investigate the timing and composition of cerebral microemboli in a paediatric population during cardiac catheterisation. Microembolic signals were related to specific catheter manipulations but were not associated with fluoroscopic time or duration of procedure.
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20
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Banahan C, Rogerson Z, Rousseau C, Ramnarine KV, Evans DH, Chung EML. An in vitro comparison of embolus differentiation techniques for clinically significant macroemboli: dual-frequency technique versus frequency modulation method. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:2642-2654. [PMID: 25218455 PMCID: PMC4195753 DOI: 10.1016/j.ultrasmedbio.2014.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 05/12/2014] [Accepted: 06/03/2014] [Indexed: 06/03/2023]
Abstract
The ability to distinguish harmful solid cerebral emboli from gas bubbles intra-operatively has potential to direct interventions to reduce the risk of brain injury. In this in vitro study, two embolus discrimination techniques, dual-frequency (DF) and frequency modulation (FM) methods, are simultaneously compared to assess discrimination of potentially harmful large pieces of carotid plaque debris (0.5-1.55 mm) and thrombus-mimicking material (0.5-2 mm) from gas bubbles (0.01-2.5 mm). Detection of plaque and thrombus-mimic using the DF technique yielded disappointing results, with four out of five particles being misclassified (sensitivity: 18%; specificity: 89%). Although the FM method offered improved sensitivity, a higher number of false positives were observed (sensitivity: 72%; specificity: 50%). Optimum differentiation was achieved using the difference between peak embolus/blood ratio and mean embolus/blood ratio (sensitivity: 77%; specificity: 81%). We conclude that existing DF and FM techniques are unable to confidently distinguish large solid emboli from small gas bubbles (<50 μm).
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Affiliation(s)
- Caroline Banahan
- Medical Physics Department, University Hospitals of Leicester NHS Trust, Leicester, UK.
| | - Zach Rogerson
- Department of Physics, University of Leicester, Leicester, UK
| | - Clément Rousseau
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | | | - David H Evans
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Emma M L Chung
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
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21
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Kwon OS, Lee HJ, Kim WS, Hong JM, Cho HJ. Risk of continuing planned surgery after endovascular repair of subclavian artery injury: a case report. Korean J Anesthesiol 2014; 67:139-43. [PMID: 25237452 PMCID: PMC4166387 DOI: 10.4097/kjae.2014.67.2.139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 01/05/2014] [Accepted: 01/05/2014] [Indexed: 11/10/2022] Open
Abstract
Endovascular repair with covered stents has been widely used to treat subclavian and axillary artery injuries and has produced promising early results. The possibility of a thromboembolism occurring in cerebral arteries during an endovascular procedure should be a cause for concern. In the case of endovascular management of arterial traumas, a prompt and sufficient period for check-up of the patient's neurological signs is needed, even if it requires postponing elective intervention for the patient's safety. We report a rare case of liver transplantation immediately after endovascular repair of an iatrogenic subclavian arterial injury to describe the risk of continuing planned surgery without neurologic assessment.
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Affiliation(s)
- O-Sun Kwon
- Department of Anesthesia and Pain Medicine, Pusan National University School of Medicine, Busan, Korea
| | - Hyeon Jeong Lee
- Department of Anesthesia and Pain Medicine, Pusan National University School of Medicine, Busan, Korea. ; Biomedical Research Institute, Pusan National University Hospital, Busan, Korea
| | - Won-Sung Kim
- Department of Anesthesia and Pain Medicine, Pusan National University School of Medicine, Busan, Korea
| | - Jung-Min Hong
- Department of Anesthesia and Pain Medicine, Pusan National University School of Medicine, Busan, Korea
| | - Hyun-Jun Cho
- Department of Anesthesia and Pain Medicine, Pusan National University School of Medicine, Busan, Korea
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22
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Cerebral microembolization during atrial fibrillation ablation: Comparison of different single-shot ablation techniques. Int J Cardiol 2014; 174:276-81. [DOI: 10.1016/j.ijcard.2014.03.175] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/10/2014] [Accepted: 03/29/2014] [Indexed: 11/19/2022]
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23
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Abstract
Microembolic signals (MES) can be detected in many recipients of mechanical aortic valve prostheses by transcranial Doppler ultrasound. The nature and etiology of these MES have remained unclear for a long time. The solid and gaseous nature of MES are discussed, as well as whether or not MES may reflect artifacts. Recently, the gaseous nature of these MES has been widely established. To understand the physics of bubble formation related to mechanical heart valve prostheses, it is necessary to discuss the different types of cavitation occurring at the prostheses and the conditions leading to the degassing of blood. We describe the history of transcranial Doppler ultrasound-techniques and the current techniques in the measurement of these signals. Furthermore, the possible clinical impact of MES, as well as strategies for the design of new prostheses and surgical alternatives to diminish their load are discussed.
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Affiliation(s)
- Axel Nötzold
- Segeberger Kliniken GmbH, Department for Cardiac and Vascular Surgery, Am Kurpark 1, 23795 Bad Segeberg, Germany.
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24
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Hassell MEC, Nijveldt R, Roos YBW, Majoie CBL, Hamon M, Piek JJ, Delewi R. Silent cerebral infarcts associated with cardiac disease and procedures. Nat Rev Cardiol 2013; 10:696-706. [PMID: 24165909 DOI: 10.1038/nrcardio.2013.162] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The occurrence of clinically silent cerebral infarcts (SCIs) in individuals affected by cardiac disease and after invasive cardiac procedures is frequently reported. Indeed, atrial fibrillation, left ventricular thrombus formation, cardiomyopathy, and patent foramen ovale have all been associated with SCIs. Furthermore, postprocedural SCIs have been observed after left cardiac catheterization, transcatheter aortic valve implantation, CABG surgery, pulmonary vein isolation, and closure of patent foramen ovale. Such SCIs are often described as precursors to symptomatic stroke and are associated with cognitive decline, dementia, and depression. Increased recognition of SCIs might advance our understanding of their relationship with heart disease and invasive cardiac procedures, facilitate further improvement of therapies or techniques aimed at preventing their occurrence and, therefore, decrease the risk of adverse neurological outcomes. In this Review, we provide an overview of the occurrence and clinical significance of, and the available diagnostic modalities for, SCIs related to cardiac disease and associated invasive cardiac procedures.
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Affiliation(s)
- Mariëlla E C Hassell
- Department of Cardiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, Netherlands
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25
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Topcuoglu MA, Unal A, Arsava EM. Advances in transcranial Doppler clinical applications. ACTA ACUST UNITED AC 2013; 4:343-58. [PMID: 23496150 DOI: 10.1517/17530059.2010.495749] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD Diagnostic neurosonology techniques including transcranial Doppler (TCD), transcranial color Doppler imaging (TCDI) and power motion-mode (PMD) TCD provide information about various aspects of cerebrovascular status such as microemboli detection, dynamic autoregulation and long-duration real-time monitoring of flow characteristics. Although most of the information provided cannot be obtained by any other imaging methodology, and is critical in clinical decision-making in the care of various neurovascular diseases, these modalities are widely underutilized. Increasing the familiarity to neurosonological techniques is of crucial importance. AREAS COVERED IN THIS REVIEW After briefly reviewing TCD, TCDI and PMD techniques, classical features are summarized and recent developments in the clinical neurosonology applications with specific interest in the neurovascular disorders. WHAT THE READER WILL GAIN Practical perspectives of ultrasound evaluation of intracranial arterial status in various neurovascular diseases including sickle cell vasculopathy and vasospasm are reviewed in detail. Pearls on the neurosonological monitoring of acute ischemic stroke and increased intracranial pressure increase is provided. Standards of cerebral microembolism detection, right to left shunts diagnosis and cerebral autoregulation assessment are discussed methodologically. Future perspectives of therapeutic neurosonology including sonothrombolysis, microbubble-ultrasound-mediated gene and drug delivery into the brain, and alteration of the brain-blood barrier permeability are summarized. TAKE HOME MESSAGE Suitable with future medicine, neurosonology brings imaging to the bedside, which enables the treating physician to monitor a given intervention in real time. A non-invasive neurosonology-guided treatment of various diseases could be possible in the near future. The first and foremost step in gaining mastery in this very fruitful field is beginning to use it.
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Affiliation(s)
- Mehmet Akif Topcuoglu
- Hacettepe University Hospitals, Department of Neurology, Neurological Intensive Care Unit, 06100, Sihhiye, Ankara, Turkey +90 312 3051806 ; +90 312 3093451 ;
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26
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Nagy-Baló E, Tint D, Clemens M, Beke I, Kovács KR, Csiba L, Édes I, Csanádi Z. Transcranial Measurement of Cerebral Microembolic Signals During Pulmonary Vein Isolation. Circ Arrhythm Electrophysiol 2013; 6:473-80. [DOI: 10.1161/circep.112.971747] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Edina Nagy-Baló
- From the Institute of Cardiology (E.N.-B., D.T., M.C., I.B., I.E., Z.C.), and Department of Neurology (K.R.K., L.C.), University of Debrecen, Debrecen, Hungary
| | - Diana Tint
- From the Institute of Cardiology (E.N.-B., D.T., M.C., I.B., I.E., Z.C.), and Department of Neurology (K.R.K., L.C.), University of Debrecen, Debrecen, Hungary
| | - Marcell Clemens
- From the Institute of Cardiology (E.N.-B., D.T., M.C., I.B., I.E., Z.C.), and Department of Neurology (K.R.K., L.C.), University of Debrecen, Debrecen, Hungary
| | - Ildikó Beke
- From the Institute of Cardiology (E.N.-B., D.T., M.C., I.B., I.E., Z.C.), and Department of Neurology (K.R.K., L.C.), University of Debrecen, Debrecen, Hungary
| | - Katalin Réka Kovács
- From the Institute of Cardiology (E.N.-B., D.T., M.C., I.B., I.E., Z.C.), and Department of Neurology (K.R.K., L.C.), University of Debrecen, Debrecen, Hungary
| | - László Csiba
- From the Institute of Cardiology (E.N.-B., D.T., M.C., I.B., I.E., Z.C.), and Department of Neurology (K.R.K., L.C.), University of Debrecen, Debrecen, Hungary
| | - István Édes
- From the Institute of Cardiology (E.N.-B., D.T., M.C., I.B., I.E., Z.C.), and Department of Neurology (K.R.K., L.C.), University of Debrecen, Debrecen, Hungary
| | - Zoltán Csanádi
- From the Institute of Cardiology (E.N.-B., D.T., M.C., I.B., I.E., Z.C.), and Department of Neurology (K.R.K., L.C.), University of Debrecen, Debrecen, Hungary
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Zanatta P, Forti A, Minniti G, Comin A, Mazzarolo AP, Chilufya M, Baldanzi F, Bosco E, Sorbara C, Polesel E. Brain emboli distribution and differentiation during cardiopulmonary bypass. J Cardiothorac Vasc Anesth 2013; 27:865-75. [PMID: 23706643 DOI: 10.1053/j.jvca.2012.12.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Cardiopulmonary bypass (CPB) is a lifesaving practice in cardiac surgery, but its use frequently is associated with cerebral injury and neurocognitive dysfunctions. Despite the involvement of numerous factors, microembolism occurring during CPB seems to be one of the main mechanisms leading to such alterations. The aim of the present study was to characterize the occurrence of cerebral microembolism with reference to microembolic amount, nature, and distribution in different combinations of cardiac procedures and CPB on the microembolic load. DESIGN A retrospective observational clinical study. SETTING A single-center regional hospital. PARTICIPANTS Fifty-five patients undergoing elective cardiac surgery with CPB. INTERVENTIONS Bilateral detection of the patients' middle cerebral arteries using a multifrequency transcranial Doppler. MEASUREMENTS AND MAIN RESULTS Patients were divided into 3 groups depending on the CPB circuit used (open, open with vacuum, or closed). There was a significant difference between the number of solid and gaseous microemboli (p<0.001), with the solid lower than the gaseous ones. The number of solid microemboli was affected by group (p< 0.05), CPB phase (p<0.001), and laterality (p<0.01). The number of gaseous microemboli was affected only by group (p<0.05) and CPB phase (p<0.001). Generally, the length of CPB phase did not affect the number of microemboli. CONCLUSIONS Surgical procedures combined with CPB circuits, but not the CPB phase length, affected the occurrence, nature, and laterality of microemboli.
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Affiliation(s)
- Paolo Zanatta
- Department of Anesthesia and Intensive Care, Treviso Regional Hospital, Italy
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28
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Messerotti Benvenuti S, Zanatta P, Valfrè C, Polesel E, Palomba D. Preliminary evidence for reduced preoperative cerebral blood flow velocity as a risk factor for cognitive decline three months after cardiac surgery: an extension study. Perfusion 2012; 27:486-92. [PMID: 22798170 DOI: 10.1177/0267659112453475] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This extension study investigated the association between preoperative cerebral blood flow (CBF) velocity and postoperative cognitive decline (POCD) at a three-month follow-up in patients who underwent cardiac surgery. Continuous transcranial Doppler ultrasound on both middle cerebral arteries (MCAs) was used preoperatively in 31 right-handed cardiac surgery patients at rest. Each patient performed a neuropsychological evaluation to assess cognitive performance before surgery, at discharge and at three-month follow-up. Patients with POCD at the three-month follow-up had a marginally significantly lower preoperative CBF velocity in the left MCA than patients without POCD. Moreover, the group with POCD had a significantly lower CBF velocity in the left than in the right MCA, whereas no difference between the left and right CBF velocity was found in the group without POCD. These preliminary findings suggest that reduced preoperative CBF velocity in the left MCA may represent an independent risk factor for cognitive decline in patients three months after surgery.
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29
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Oliveira-Filho J, Dias JDS, Jesus PA, Neto NJ, Aras R, Reis FJ, Furie KL. Clinical assessment, neuroimaging and immunomarkers in Chagas disease study (CLINICS): Rationale, study design and preliminary findings. Dement Neuropsychol 2012; 6:180-187. [PMID: 29213794 PMCID: PMC5618967 DOI: 10.1590/s1980-57642012dn06030012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 05/20/2012] [Indexed: 11/21/2022] Open
Abstract
Chagas disease (CD) is an important cause of cardiomyopathy and stroke in Brazil. Brain infarcts and atrophy seem to occur independently of cardiomyopathy severity and cognitive impairment is understudied. OBJECTIVE Compare the prevalence of brain magnetic resonance imaging abnormalities between patients with or without CD; determine if inflammatory biomarkers are increased in CD; and determine the efficacy of aspirin in reducing the rate of microembolization in these patients. METHODS 500 consecutive patients with heart failure will undergo a structured cognitive evaluation, biomarker collection and search for microembolic signals on transcranial Doppler. The first 90 patients are described, evaluated with cognitive tests and brain magnetic resonance imaging to measure N-acetyl aspartate (NAA), choline (Cho), myo-inositol (MI) and creatine (Cr). RESULTS Mean age was 55±11 years, 51% female, 38 (42%) with CD. Mean NAA/Cr ratio was lower in patients with CD as compared to other cardiomyopathies. Long-term memory and clock-drawing test were also significantly worse in CD patients. In the multivariable analysis correcting for ejection fraction, age, sex and educational level, reduced NAA/Cr (p=0.006) and cognitive dysfunction (long-term memory, p=0.023; clock-drawing test, p=0.015) remained associated with CD. CONCLUSION In this preliminary sample, CD was associated with cognitive impairment and decreased NAA/Cr independently of cardiac function or educational level.
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Affiliation(s)
- Jamary Oliveira-Filho
- From the Stroke and Cardiomyopathy Clinics of the Hospital Universitario
Professor Edgard Santos, Federal University of Bahia, BA, Brazil; and the Stroke
Service of Massachusetts General Hospital, Harvard University, USA
| | - Jesângeli de S. Dias
- From the Stroke and Cardiomyopathy Clinics of the Hospital Universitario
Professor Edgard Santos, Federal University of Bahia, BA, Brazil; and the Stroke
Service of Massachusetts General Hospital, Harvard University, USA
| | - Pedro A.P. Jesus
- From the Stroke and Cardiomyopathy Clinics of the Hospital Universitario
Professor Edgard Santos, Federal University of Bahia, BA, Brazil; and the Stroke
Service of Massachusetts General Hospital, Harvard University, USA
| | - Nestor J.S.B. Neto
- From the Stroke and Cardiomyopathy Clinics of the Hospital Universitario
Professor Edgard Santos, Federal University of Bahia, BA, Brazil; and the Stroke
Service of Massachusetts General Hospital, Harvard University, USA
| | - Roque Aras
- From the Stroke and Cardiomyopathy Clinics of the Hospital Universitario
Professor Edgard Santos, Federal University of Bahia, BA, Brazil; and the Stroke
Service of Massachusetts General Hospital, Harvard University, USA
| | - Francisco J.F.B. Reis
- From the Stroke and Cardiomyopathy Clinics of the Hospital Universitario
Professor Edgard Santos, Federal University of Bahia, BA, Brazil; and the Stroke
Service of Massachusetts General Hospital, Harvard University, USA
| | - Karen L. Furie
- From the Stroke and Cardiomyopathy Clinics of the Hospital Universitario
Professor Edgard Santos, Federal University of Bahia, BA, Brazil; and the Stroke
Service of Massachusetts General Hospital, Harvard University, USA
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30
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Goldberg I, Auriel E, Russell D, Korczyn AD. Microembolism, silent brain infarcts and dementia. J Neurol Sci 2012; 322:250-3. [PMID: 22429666 DOI: 10.1016/j.jns.2012.02.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Accepted: 02/22/2012] [Indexed: 10/28/2022]
Abstract
Cognitive decline becomes more prevalent than ever in parallel with the increasing life expectancy of the population. Alzheimer' disease (AD) and cerebral vascular lesions are common in the elderly and represent, with increased age, the most frequent contributors to cognitive decline. It is now believed that these pathologies frequently coexist in the same brain. The border discriminating vascular dementia from AD is blurred and challenges our understanding of these clinical entities. Further research, at both basic and clinical levels, is mandatory in order to better understand the interactions of vascular ischemic injury and primary degenerative physiopathologies of the brain, in order to prevent and better manage patients with cognitive decline. We review recent published clinical evidence of silent brain ischemia as a contributor to cognitive decline and dementia. Microemboli, from both cardiac and vascular origins, have been shown to be associated with structural changes in the brain. The role of transcranial Doppler as an objective tool for detecting and quantifying microemboli is discussed in light of recent clinical evidence.
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Affiliation(s)
- I Goldberg
- Department of Neurology, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Israel.
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Zanatta P, Benvenuti SM, Valfrè C, Baldanzi F, Palomba D. The role of asymmetry and the nature of microembolization in cognitive decline after heart valve surgery: a pilot study. Perfusion 2012; 27:199-206. [DOI: 10.1177/0267659112437776] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Our objective was to determine the role of asymmetry and the nature of microembolization on postoperative cognitive decline in patients who had undergone heart valve surgery. Continuous transcranial Doppler ultrasound was intraoperatively used for both middle cerebral arteries in 13 right-handed heart valve surgery patients to detect microembolization. The Trail Making Test A and B, Memory with 10/30 s interference, the Digit Span Test and Phonemic Fluency were performed preoperatively, at discharge and three months after surgery. Our data suggest that early and late postoperative psychomotor and executive functions may be sensitive to microemboli in the left, but not in the right middle cerebral artery. Moreover, solid and gaseous microemboli are both similarly associated with early postoperative cognitive decline while, surprisingly, late postoperative cognitive decline is more likely to be associated with gaseous than solid microemboli.
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Affiliation(s)
- P Zanatta
- Anesthesia and Intensive Care Department, Treviso Regional Hospital, Italy
| | | | - C Valfrè
- Cardiovascular Disease Department, Treviso Regional Hospital, Italy
| | - F Baldanzi
- Regional project for the reduction of neurodysfunction after cardiac surgery and neurosurgery, and the improvement of multimodality neuromonitoring, Regione Veneto, Italy
| | - D Palomba
- Department of General Psychology, University of Padova, Italy
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Preoperative cerebral hypoperfusion in the left, not in the right, hemisphere is associated with cognitive decline after cardiac surgery. Psychosom Med 2012; 74:73-80. [PMID: 22155944 DOI: 10.1097/psy.0b013e3182383a94] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Postoperative cognitive decline (POCD) is a frequent complication after cardiac surgery. Although intraoperative events are risk factors for POCD, the role played by preoperative hypoperfusion in cognitive decline has not yet been investigated. It is also unknown whether the impact of preoperative hypoperfusion in the left or right middle cerebral arteries (MCAs) can differentially account for POCD. The main aims of this study were to investigate whether preoperative cerebral hypoperfusion was associated with early POCD and whether lateralized hypoperfusion would differentially affect POCD in patients after cardiac surgery. METHODS Bilateral MCA continuous transcranial Doppler (TCD) sonography was preoperatively performed at rest in 31 right-handed patients who underwent cardiac surgery to detect cerebral blood flow (CBF) velocity. All patients completed a neuropsychological evaluation to assess attention, short-term memory, working memory, and psychomotor function before surgery and at discharge. POCD was defined using the standard deviation method. Logistic regression was used to investigate the association between hypoperfusion and POCD, controlling for common preoperative risk factors. RESULTS Fourteen patients (45%) exhibited POCD. Cerebral hypoperfusion in the left MCA selectively predicted the incidence of POCD (odds ratio = 0.90, p < .02), whereas CBF velocity in the right MCA was unrelated to POCD (odds ratio = 1.07, p = .39). CONCLUSIONS Patients who underwent cardiac surgery with reduced CBF velocity in the left MCA preoperatively are at greater risk for POCD. Left cerebral hypoperfusion may also represent an independent predictor of POCD in these patients. TCD evaluation may have substantial clinical benefits for the detection of patients at high risk of POCD after cardiac surgery.
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Jurga J, Nyman J, Tornvall P, Mannila MN, Svenarud P, van der Linden J, Sarkar N. Cerebral Microembolism During Coronary Angiography. Stroke 2011; 42:1475-7. [DOI: 10.1161/strokeaha.110.608638] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Background and Purpose—
Microemboli observed during coronary angiography can cause silent ischemic cerebral lesions. The aim of this study was to investigate if the number of particulate cerebral microemboli during coronary angiography is influenced by access site used.
Methods—
Fifty-one patients with stable angina pectoris referred for coronary angiography were randomized to right radial or right femoral arterial access. The number of particulate microemboli passing the middle cerebral arteries was continuously registered with transcranial Doppler.
Results—
The median (minimum–maximum range) numbers of particulate emboli were significantly higher with radial 10 (1–120) than with femoral 6 (1–19) access. More particulate microemboli passed the right middle cerebral artery with the radial access.
Conclusions—
This study indicates that the radial access used for coronary angiography generates more particulate cerebral microemboli than the femoral access and thus may influence the occurrence of silent cerebral injuries.
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Affiliation(s)
- Juliane Jurga
- From Cardiology Unit, Department of Medicine (J.J., P.T., M.N.M., N.S.), and Department of Molecular Medicine and Surgery (J.N., P.S., J.v.d.L.), Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Jesper Nyman
- From Cardiology Unit, Department of Medicine (J.J., P.T., M.N.M., N.S.), and Department of Molecular Medicine and Surgery (J.N., P.S., J.v.d.L.), Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Per Tornvall
- From Cardiology Unit, Department of Medicine (J.J., P.T., M.N.M., N.S.), and Department of Molecular Medicine and Surgery (J.N., P.S., J.v.d.L.), Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Maria Nastase Mannila
- From Cardiology Unit, Department of Medicine (J.J., P.T., M.N.M., N.S.), and Department of Molecular Medicine and Surgery (J.N., P.S., J.v.d.L.), Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Peter Svenarud
- From Cardiology Unit, Department of Medicine (J.J., P.T., M.N.M., N.S.), and Department of Molecular Medicine and Surgery (J.N., P.S., J.v.d.L.), Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Jan van der Linden
- From Cardiology Unit, Department of Medicine (J.J., P.T., M.N.M., N.S.), and Department of Molecular Medicine and Surgery (J.N., P.S., J.v.d.L.), Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Nondita Sarkar
- From Cardiology Unit, Department of Medicine (J.J., P.T., M.N.M., N.S.), and Department of Molecular Medicine and Surgery (J.N., P.S., J.v.d.L.), Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
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Benoudjit N, Ferroudji K, Bahaz M, Bouakaz A. In vitro microemboli classification using neural network models and RF signals. ULTRASONICS 2011; 51:247-252. [PMID: 20888614 DOI: 10.1016/j.ultras.2010.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Revised: 08/29/2010] [Accepted: 09/05/2010] [Indexed: 05/29/2023]
Abstract
Emboli classification is of high clinical importance for selecting appropriate treatment for patients. Several ultrasonic (US) methods using Doppler processing have been used for emboli detection and classification as solid or gaseous matter. We suggest in this experimental study exploiting the Radio-Frequency (RF) signal backscattered by the emboli since they contain additional information on the embolus than the Doppler signal. The aim of the study is the analysis of RF signals using Multilayer Perceptron (MLP) and Radial-Basis Function Network (RBFN) in order to classify emboli. Anthares scanner with RF access was used with a transmit frequency of 1.82MHz at two mechanical indices (MI) 0.2 and 0.6. The mechanical index is given as the peak negative pressure (in MPa) divided by the square root of the frequency (in MHz). A Doppler flow phantom was used containing a 0.8mm diameter vessel surrounded by a tissue mimicking material. To imitate gas emboli US behaviour, Sonovue microbubbles were injected at two different doses (10μl and 5μl) in a nonrecirculating at a constant flow. The surrounding tissue was assumed to behave as a solid emboli. In order to mimic real clinical pathological situations, Sonovue concentration was chosen such that the fundamental scattering from the tissue and from the contrast were identical. The amplitudes and bandwidths of the fundamental and the 2nd harmonic components were selected as input parameters to the MLP and RBFN models. Moreover the frequency bandwidths of the fundamental and the 2nd harmonic echoes were approximated by Gaussian functions and the coefficients were used as a third input parameter to the neural network models. The results show that the Gaussian coefficients provide the highest rate of classification in comparison to the amplitudes and the bandwidths of the fundamental and the 2nd harmonic components. The classification rates reached 89.28% and 92.85% with MLP and RBFN models respectively. This short communication demonstrates the opportunity to classify emboli based on a RF signals and neural network analysis.
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Affiliation(s)
- N Benoudjit
- Laboratoire d'Electronique Avancée, Université de Batna, Algeria
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Choi Y, Saqqur M, Asil T, Jin A, Stewart E, Stephenson C, Ibrahim M, Roy J, Boulanger JM, Coutts S, Khan F, Demchuk AM. A combined power m-mode and single gate transcranial doppler ultrasound microemboli signal criteria for improving emboli detection and reliability. J Neuroimaging 2011; 20:359-67. [PMID: 19912481 DOI: 10.1111/j.1552-6569.2009.00446.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Single gate transcranial Doppler spectrogram (sgTCD) has a high variability in the detection of microembolic signals (MES), Adding Power M-mode Doppler (PMD) information may improve MES detection. Our study's aim is to derive combined PMD/sgTCD microemboli criteria to overcome this limitation. METHODS Patients with symptomatic carotid disease were prospectively enrolled within 24 h of symptom onset underwent 1 hour TCD emboli monitoring. We reviewed disparity between PMD MES criteria and sgTCD MES criteria. We compared combined PMD/sgTCD criteria to sgTCD alone criteria by measuring the intraclass correlation coefficient (ICC). RESULTS Of 92 patients, 28 patients had evidence of MES on sgTCD or PMD. Total MES count was 269 based on sgTCD criteria, and 326 based on combined PMD/sgTCD criteria (P= 0.005). Combined PMD/sgTCD criteria revealed 17 MESs (4.8%) based on sgTCD criteria to represent artifacts and 57 MESs (17.5%) not to be detected by sgTCD criteria. Overall ICC based on sgTCD criteria was 0.67 [95% confidence interval (CI): 0.58-0.74]; however, introducing combined PMD/sgTCD criteria resulted in a significant increase in the ICC, 0.91 (95% CI: 0.88-0.93). CONCLUSION Our combined PMD/sgTCD criteria for MES appeared to improve the yield of MES detection. Reliability in MES detection interpretation was improved when combined PMD/sgTCD criteria was applied.
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Affiliation(s)
- Youngbin Choi
- Department of Neurology, Catholic University of Korea, Seoul, South Korea
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Meairs S, Hennerici M, Mohr J. Ultrasonography. Stroke 2011. [DOI: 10.1016/b978-1-4160-5478-8.10044-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Rosenkranz M, Russjan A, Goebell E, Havemeister S, Thomalla G, Cheng B, Beck C, Krützelmann A, Fiehler J, Gerloff C. Carotid Plaque Surface Irregularity Predicts Cerebral Embolism during Carotid Artery Stenting. Cerebrovasc Dis 2011; 32:163-9. [DOI: 10.1159/000328883] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 04/21/2011] [Indexed: 11/19/2022] Open
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Girault JM, Kouamé D, Ménigot S, Souchon G, Tranquart F. Analysis of index modulation in microembolic Doppler signals part I: radiation force as a new hypothesis-simulations. ULTRASOUND IN MEDICINE & BIOLOGY 2011; 37:87-101. [PMID: 21084152 DOI: 10.1016/j.ultrasmedbio.2010.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 09/07/2010] [Accepted: 09/17/2010] [Indexed: 05/30/2023]
Abstract
The purpose of this study was to reveal the cause of frequency modulation (FM) present in microembolic Doppler ultrasound signals. This novel explanation should help the development of sensitive microembolus discrimination techniques. We suggest that the frequency modulation detected is caused by the ultrasonic radiation force (URF) acting directly on microemboli. The frequency modulation and the imposed displacement were calculated using a numerical dynamic model. By setting simulation parameters with practical values, it was possible to reproduce most microembolic frequency modulation signatures. The most interesting findings in this study were that: (1) the ultrasound radiation force acting on a gaseous microembolus and its corresponding cumulative displacement were far higher than those obtained for a solid microembolus, and that is encouraging for discrimination purposes; and 2) the calculated frequency modulation indices (FMIs) (≈20 kHz) were in good agreement with literature results. By taking into account the URF, the flow pulsatility, the beam-to-flow angle and both the velocity and the ultrasound beam profiles, it was possible to explain all erratic FM signatures of a microbubble. Finally, by measuring FMI from simulated Doppler signals and by using a constant threshold of 1 KHz, it was possible to discriminate gaseous from solid microemboli with ease.
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Affiliation(s)
- Jean-Marc Girault
- Université François Rabelais de Tours, UMRS Imaging and Brain, Tours, France.
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Postoperative neurocognitive function and microembolus detection in patients undergoing neck dissection: a pilot study. Eur J Anaesthesiol 2010; 27:417-24. [PMID: 20394111 DOI: 10.1097/eja.0b013e328336c633] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND OBJECTIVE Patients undergoing oncologic neck dissection may have many of the risk factors for carotid artery stenosis, thus predisposing them to perioperative cerebral ischaemic events. The present study was designed to investigate development of postoperative neurocognitive dysfunction in these patients. METHODS Twenty-six patients were assessed the day before surgery and 48 h and 12 months after surgery using a comprehensive neuropsychological test battery. Cognitive performance was compared with a matched control group to account for the practise effect associated with repeated testing. Doppler ultrasonography was used to detect intraoperative cerebral microembolism. S100beta protein values were evaluated before and immediately after anaesthesia. RESULTS On the second postoperative day, 26.9% of patients undergoing neck dissection had postoperative neurocognitive deficit (POCD), defined as a total deficit score of 2SD worse than the mean performance in the control group. Microemboli were found only in the neck dissection group. S100beta levels were significantly higher after neck dissection (Wilcoxon signed ranked test: P<0.001). After 12 months, the incidence of POCD was similar in both groups. CONCLUSION POCD was detectable only after neck dissection in the early postoperative period accompanied by increased incidence of microembolism and protein S100beta levels, but not 12 months after surgery.
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Boivie P, Hedberg M, Engström KG. Size distribution of embolic material produced at aortic cross-clamp manipulation. SCAND CARDIOVASC J 2010; 44:367-72. [DOI: 10.3109/14017431.2010.501867] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Discrimination of Types of Venous Emboli Using Doppler Ultrasound. Ann Vasc Surg 2010; 24:721-7. [DOI: 10.1016/j.avsg.2010.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 01/25/2010] [Accepted: 03/01/2010] [Indexed: 11/24/2022]
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Kruis RWJ, Vlasveld FAE, Van Dijk D. The (Un)Importance of Cerebral Microemboli. Semin Cardiothorac Vasc Anesth 2010; 14:111-8. [DOI: 10.1177/1089253210370903] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background: The use of cardiopulmonary bypass (CPB) is associated with cerebral microemboli. Cognitive decline after cardiac surgery has therefore always been attributed to the use of CPB. However, randomized studies comparing coronary bypass surgery with and without CPB failed to establish a clear cognitive benefit of avoiding CPB. The aim of this analysis was to systematically review the studies that directly assessed the association between cerebral microemboli and cognitive decline after cardiac surgery. Methods: The electronic database of PubMed of the National Library of Medicine from 1980 until 2009 was searched to identify relevant literature. Search terms related to “cardiac surgery,” “microemboli,” and “cognitive decline” were used. Studies were reviewed independently by 2 reviewers and relevant articles were included completely if they matched the selection criteria. This review included studies in adult cardiac surgical patients reporting both a measure of cerebral embolic load and cognitive outcomes. Results: The literature search yielded 423 different titles, of which 22 met the selection criteria. All 22 studies used neuropsychological tests to determine cognitive outcome. Seven studies used postoperative (diffusion-weighted) magnetic resonance imaging (MRI) to detect cerebral emboli and 15 studies used intraoperative transcranial Doppler imaging. In 1 MRI study and 5 Doppler studies, an association was found between the number of cerebral emboli and the risk of postoperative cognitive decline. In 15 studies, such an association could not be established. One study did not assess the direct relation between microemboli and cognitive decline. Conclusion: This systematic review could neither confirm nor rule out a causal link between emboli from CPB and postoperative cognitive decline.
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Rudolph JL, Babikian VL, Treanor P, Pochay VE, Wigginton JB, Crittenden MD, Marcantonio ER. Microemboli are not associated with delirium after coronary artery bypass graft surgery. Perfusion 2010; 24:409-15. [PMID: 20093336 DOI: 10.1177/0267659109358207] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Delirium is an acute change in cognition which occurs frequently after coronary artery bypass graft (CABG) surgery. Cerebral microemboli, from plaque, air, or thrombus, have been hypothesized to contribute to delirium and cognitive decline after CABG. The purpose of this study was to determine if there was an association between cerebral microemboli and delirium after cardiac surgery. Non-delirious patients (n=68) were prospectively enrolled and underwent intraoperative monitoring of the middle cerebral arteries with transcranial Doppler (TCD). TCD signals were saved and analyzed postoperatively for microemboli manually, according to established criteria. Postoperatively, patients were assessed for delirium with a standardized battery. Thirty-three patients (48.5%) developed delirium after surgery. Microemboli counts (mean + or - SD) were not significantly different in those with and without delirium (303 + or - 449 vs. 299 + or - 350; p=0.97). While intraoperative microemboli were not associated with delirium after CABG, further investigation into the source and composition of microemboli can further elucidate the long-term clinical impact of microemboli.
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Affiliation(s)
- James L Rudolph
- Geriatric Research, Education, and Clinical Center, Boston VA Healthcare System, Boston, MA 02130, USA.
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Zanatta P, Forti A, Bosco E, Salvador L, Borsato M, Baldanzi F, Longo C, Sorbara C, Longatti P, Valfrè C. Microembolic signals and strategy to prevent gas embolism during extracorporeal membrane oxygenation. J Cardiothorac Surg 2010; 5:5. [PMID: 20132556 PMCID: PMC2825509 DOI: 10.1186/1749-8090-5-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Accepted: 02/04/2010] [Indexed: 11/30/2022] Open
Abstract
Background Extracorporeal membrane oxygenation (ECMO) supplies systemic blood perfusion and gas exchange in patients with cardiopulmonary failure. The current literature lacks of papers reporting the possible risks of microembolism among the complications of this treatment. In this study we present our preliminary experience on brain blood flow velocity and emboli detection through the transcranial Doppler monitoring during ECMO. Methods Six patients suffering of heart failure, four after cardiac surgery and two after cardiopulmonary resuscitation were treated with ECMO and submitted to transcranial doppler monitoring to accomplish the neurophysiological evaluation for coma. Four patients had a full extracorporeal flow supply while in the remaining two patients the support was maintained 50% in respect to normal demand. All patients had a bilateral transcranial brain blood flow monitoring for 15 minutes during the first clinical evaluation. Results Microembolic signals were detected only in patients with the full extracorporeal blood flow supply due to air embolism. Conclusions We established that the microembolic load depends on gas embolism from the central venous lines and on the level of blood flow assistance. The gas microemboli that enter in the blood circulation and in the extracorporeal circuits are not removed by the membrane oxygenator filter. Maximum care is required in drugs and fluid infusion of this kind of patients as a possible source of microemboli. This harmful phenomenon may be overcome adding an air filter device to the intravenous catheters.
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Affiliation(s)
- Paolo Zanatta
- Anestesia and Intensive Care Department, Treviso Regional Hospital, Italy.
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Skjelland M, Krohg-Sørensen K, Tennøe B, Bakke SJ, Brucher R, Russell D. Cerebral microemboli and brain injury during carotid artery endarterectomy and stenting. Stroke 2008; 40:230-4. [PMID: 18927460 DOI: 10.1161/strokeaha.107.513341] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND PURPOSE Cerebral microembolic signals detected by transcranial Doppler are frequent during carotid angioplasty with stenting and carotid endarterectomy (CEA). Their potential harmful effects on the brain are, however, unclear. The aim of this study was to relate the frequency and type of per-procedural microembolic signals to procedure-related ipsilateral ischemic strokes and new ipsilateral ischemic lesions on diffusion-weighted cerebral MRI. METHODS Eighty-five patients who were prospectively treated with CEA (61) or carotid angioplasty with stenting (30) for high-grade (>/=70%) internal carotid artery stenoses were monitored during the procedures using multifrequency transcranial Doppler with embolus detection and differentiation. Pre- and postprocedural cerebral diffusion-weighted cerebral MRIs were performed on a subset of patients. RESULTS Solid and gaseous microemboli were independently associated with procedure-related ipsilateral ischemic strokes (solid: P=0.027, gaseous: P=0.037) or new ipsilateral diffusion-weighted cerebral MRI lesions (solid: P=0.043, gaseous: P=0.026). Microembolic signals were detected during all procedures except one (CEA); 17% and 21% of all emboli were solid during carotid angioplasty with stenting and CEA, respectively. Patients undergoing carotid angioplasty with stenting had more solid (P<0.001) and gaseous (P<0.001) emboli and more new ipsilateral ischemic strokes (P=0.033) compared with patients undergoing CEA. Echolucent plaques (P=0.020) and preprocedural diffusion-weighted cerebral MRI ischemic lesions (P=0.002) were associated with increased numbers of solid emboli. CONCLUSIONS Solid and gaseous microemboli were increased in patients with procedure-related ipsilateral ischemic strokes or new diffusion-weighted cerebral MRI lesions, which suggests that both solid and gaseous emboli may be harmful to the brain during CEA and carotid angioplasty with stenting.
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Affiliation(s)
- Mona Skjelland
- Department of Neurology, Rikshospitalet Universty Hospital, 0027 Oslo, Norway.
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Zanatta P, Bosco E, Salandin V, Salvador L, Valfrè C, Sorbara C. Microbubbles detection during cardiopulmonary bypass with transoesophageal echocardiography: a case report. CASES JOURNAL 2008; 1:141. [PMID: 18775067 PMCID: PMC2542348 DOI: 10.1186/1757-1626-1-141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Accepted: 09/05/2008] [Indexed: 11/10/2022]
Abstract
INTRODUCTION Microembolic signals are usually detected with transcranial doppler during cardiac surgery.This report focuses on suggesting the transesophageal echocardiography as a different diagnostic approach to detect microemboli during cardiopulmonary bypass. CASE PRESENTATION A 58 year old male patient, caucasian race, was operated on video assisted minimally invasive mitral valve repair using right minithoracotomy approach. His past medical history included an uncontrolled hypertension, dyslipidemia, insulin dependent diabetes mellitus, carotid arteries stenosis. The extracorporeal circulation was performed with femoral-femoral artery and venous approach. Negative pressure for vacuum assist venous drainage was applied in order to facilitate venous blood return. The patient had a brain monitoring with bilateral transcranial doppler of middle cerebral arteries and a double channels electroencephalogram. A three dimensional transesophageal echocardiography to evaluate the mitral valve repair was performed.During the cardiopulmonary bypass a significant microembolic activity was detected in the middle cerebral arteries spectrum velocities due to gas embolism from venous return. Simultaneous recording of microbubbles was also observed on the descending thoracic aorta transesophageal echo views. CONCLUSION During the aortic cross-clamping time the transesophageal echocardiography can be useful as an alternative method to assess the amount of gas embolism coming from cardiopulmonary bypass. These informations can promote immediate interaction between perfusionist, surgeon and anesthesiologist to perform adequate manoeuvres in order to reduce the microembolism during extracorporeal circulation.
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Affiliation(s)
- Paolo Zanatta
- Anesthesia and Intensive Care Department, Treviso Regional Hospital, Piazzale Ospedale n degrees 1, 31100 Treviso, Italy.
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Martin KK, Wigginton JB, Babikian VL, Pochay VE, Crittenden MD, Rudolph JL. Intraoperative cerebral high-intensity transient signals and postoperative cognitive function: a systematic review. Am J Surg 2008; 197:55-63. [PMID: 18723157 DOI: 10.1016/j.amjsurg.2007.12.060] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Revised: 12/06/2007] [Accepted: 12/06/2007] [Indexed: 11/28/2022]
Abstract
BACKGROUND Much attention in the literature has focused on the relationship between perioperative microemboli during cardiac and vascular surgery and postoperative cognitive decline. Transcranial Doppler ultrasonography (TCD) has been used to measure high-intensity transient signals (HITS), which represent microemboli during cardiac, vascular, and orthopedic surgery. The purpose of this study was to systematically examine the literature with respect to HITS and postoperative cognitive function. METHODS Systematic PubMed searches identified articles related to the use of TCD and cognitive function in the surgical setting. RESULTS The literature remains largely undecided on the role of HITS and cognitive impairment after surgery, with most studies being underpowered to show a relationship. Although the cognitive effects of HITS may be difficult to detect, subclinical microemboli present potential harm, which may be modifiable. CONCLUSIONS TCD represents a tool for intraoperative cerebral monitoring to reduce the number of HITS during surgery.
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Affiliation(s)
- Kristin K Martin
- Plaza Medical Center, General Surgery Residency, Fort Worth, TX, USA
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Barak M, Kabha M, Norman D, Soudry M, Kats Y, Milo S. Cerebral microemboli during hip fracture fixation: a prospective study. Anesth Analg 2008; 107:221-5. [PMID: 18635491 DOI: 10.1213/ane.0b013e3181770abb] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Recent studies have shown that cerebral fat microembolism takes place during surgery for hip or knee replacement. In this study, we examined the occurrence of cerebral microembolism, solid or gas, during a standard procedure of hip fracture fixation. METHODS This was a prospective study of patients who underwent urgent surgery with a dynamic hip screw for hip fracture fixation. During surgery, patients were monitored with transcranial Doppler for detection of microemboli from right and left middle cerebral arteries. RESULTS Twenty-two patients were included in the study; their median age was 82 yr (range, 51-97 yr). In nine (41%) patients, high intensity transient signals were recorded, indicating microemboli passage in the middle cerebral arteries. All nine patients had signals of both solid and gas emboli. One of these nine patients had a postoperative cerebrovascular accident. CONCLUSIONS The incidence of cerebral microemboli during urgent surgery for hip fracture fixation is considerable. This phenomenon is not confined to hip or knee replacement surgery. The clinical implications of this finding require further investigation.
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Affiliation(s)
- Michal Barak
- Department of Anesthesiology, Rambam Health Care Campus and B. Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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Guerrieri Wolf L, Choudhary BP, Abu-Omar Y, Taggart DP. Solid and gaseous cerebral microembolization after biologic and mechanical aortic valve replacement: investigation with multirange and multifrequency transcranial Doppler ultrasound. J Thorac Cardiovasc Surg 2008; 135:512-20. [PMID: 18329462 DOI: 10.1016/j.jtcvs.2007.07.062] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2007] [Revised: 07/08/2007] [Accepted: 07/10/2007] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Cerebral microembolization is a well-recognized phenomenon after cardiac valve replacement, but the relative proportion of solid and gaseous emboli is uncertain. Particulate microemboli are thought to be the most damaging. With the use of multifrequency transcranial Doppler ultrasound, we compared the number and nature of microemboli in recipients of biologic and mechanical aortic valve prostheses. METHODS The middle cerebral arteries of 60 patients were monitored bilaterally with a new-generation transcranial Doppler ultrasound (Embo-Dop, DWL Elektronische Systeme GmbH, Singen, Germany) that rejects artefacts online and automatically discriminates between solid and gaseous microemboli. All recordings were performed during a 30-minute period 1 day before and at a mean of 5 days and 3 months after isolated aortic valve replacement with a biologic (30, group B) or mechanical (30, group M) prosthesis. RESULTS The patients in group B were older, with a mean age of 70.6 +/- 9.7 years versus 55.4 +/- 9.4 years (P < .005) in the patients in group M. Biologic prosthesis recipients were all taking aspirin (no warfarin); patients with mechanical valves were well anticoagulated with warfarin both 5 days and 3 months after surgery. None of the patients had solid microemboli preoperatively. Five days postoperatively, the absolute number of cerebral microemboli was 145 and 594 for total microemboli (P = .001) and 41 and 182 for solid microemboli (P = .002) in groups B and M, respectively. At 3 months, the absolute number was 65 and 608 for total microemboli (P < .001) and 10 and 188 for solid microemboli (P < .001) in groups B and M, respectively. Solid microemboli accounted for 16% of the total microembolic load in group B compared with 31% in group M (P = .05) at 3 months. CONCLUSIONS Solid cerebral microemboli represent approximately one third of the total cerebral microembolic load after mechanical aortic valve replacement and are detectable in the majority of such patients both 5 days and 3 months after surgery. The neurofunctional consequences of this phenomenon should be carefully assessed.
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50
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Skjelland M, Michelsen A, Brosstad F, Svennevig JL, Brucher R, Russell D. Solid Cerebral Microemboli and Cerebrovascular Symptoms in Patients With Prosthetic Heart Valves. Stroke 2008; 39:1159-64. [DOI: 10.1161/strokeaha.107.493031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Mona Skjelland
- From the Department of Neurology (M.S., D.R.), the Research Institute for Internal Medicine (A.M., F.B.), and the Department of Thoracic and Cardiac Surgery (J.L.S.), Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway, and the Department of Medical Engineering (R.B.), University of Applied Sciences, Ulm, Germany
| | - Annika Michelsen
- From the Department of Neurology (M.S., D.R.), the Research Institute for Internal Medicine (A.M., F.B.), and the Department of Thoracic and Cardiac Surgery (J.L.S.), Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway, and the Department of Medical Engineering (R.B.), University of Applied Sciences, Ulm, Germany
| | - Frank Brosstad
- From the Department of Neurology (M.S., D.R.), the Research Institute for Internal Medicine (A.M., F.B.), and the Department of Thoracic and Cardiac Surgery (J.L.S.), Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway, and the Department of Medical Engineering (R.B.), University of Applied Sciences, Ulm, Germany
| | - Jan L. Svennevig
- From the Department of Neurology (M.S., D.R.), the Research Institute for Internal Medicine (A.M., F.B.), and the Department of Thoracic and Cardiac Surgery (J.L.S.), Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway, and the Department of Medical Engineering (R.B.), University of Applied Sciences, Ulm, Germany
| | - Rainer Brucher
- From the Department of Neurology (M.S., D.R.), the Research Institute for Internal Medicine (A.M., F.B.), and the Department of Thoracic and Cardiac Surgery (J.L.S.), Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway, and the Department of Medical Engineering (R.B.), University of Applied Sciences, Ulm, Germany
| | - David Russell
- From the Department of Neurology (M.S., D.R.), the Research Institute for Internal Medicine (A.M., F.B.), and the Department of Thoracic and Cardiac Surgery (J.L.S.), Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway, and the Department of Medical Engineering (R.B.), University of Applied Sciences, Ulm, Germany
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