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Lilja D, Schalit I, Espinoza A, Hoel TN, Larsen G, Pettersen FJ, Halvorsen PS. Extracorporeal driveline vibrations to detect left ventricular assist device thrombosis - A porcine model study. J Heart Lung Transplant 2024; 43:111-119. [PMID: 37673384 DOI: 10.1016/j.healun.2023.08.022] [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] [Received: 03/20/2023] [Revised: 08/10/2023] [Accepted: 08/31/2023] [Indexed: 09/08/2023] Open
Abstract
BACKGROUND Pump thrombosis (PT) and related adverse complications contributed to the HeartWare Ventricular Assist Device (HVAD) market withdrawal. Many patients still receive lifelong support, with deficient PT surveillance based on pump power trends. Analysis of pump vibrations is better for detecting PT. Here, we investigated the feasibility of an extracorporeal accelerometer to detect PT from pump vibrations propagated out on the driveline. METHODS In a porcine HVAD model (n = 6), an accelerometer was attached to the pump as a reference and another to the driveline for comparisons of signals. In total, 59 thrombi were injected into the heart to induce PT, followed by intermittent thrombus washout maneuvers. Signals were compared visually in spectrograms and quantitatively in third harmonic saliences (S3H) by correlation analysis. Receiver operating characteristic curves expressed the method's outcome in sensitivity vs specificity, with the overall diagnostic performance in the area under the curve (AUC) score. RESULTS Five experiments had good driveline signal strength, with clear spectrographic relationships between the 2 accelerometers. Third harmonic driveline vibrations were visible 20 vs 30 times in the reference. The comparison in S3H showed a strong correlation and yielded an AUC of 0.85. Notably, S3H proved robust regarding noise and false PT detections. CONCLUSIONS An extracorporeal accelerometer on the driveline can be a readily available method for accurate HVAD PT detection before an accelerometer integration with left ventricular assist device is feasible.
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Affiliation(s)
- Didrik Lilja
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
| | - Itai Schalit
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo, Norway
| | - Andreas Espinoza
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo, Norway
| | - Tom Nilsen Hoel
- Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway
| | - Guttorm Larsen
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo, Norway
| | - Fred-Johan Pettersen
- Department of Clinical and Biomedical Engineering, Oslo University Hospital, Oslo, Norway; Department of Physics, University of Oslo, Oslo, Norway
| | - Per Steinar Halvorsen
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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Lilja D, Schalit I, Espinoza A, Fiane AE, Dahle G, Littorin-Sandbu H, Pettersen FJ, Russell KE, Thiara APS, Elle OJ, Halvorsen PS. Detection of inflow obstruction in left ventricular assist devices by accelerometer: A porcine model study. J Heart Lung Transplant 2023; 42:1005-1014. [PMID: 37023840 DOI: 10.1016/j.healun.2023.03.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 03/10/2023] [Accepted: 03/27/2023] [Indexed: 04/08/2023] Open
Abstract
BACKGROUND Left ventricular assist devices (LVAD) provide circulatory blood pump support for severe heart failure patients. Pump inflow obstructions may lead to stroke and pump malfunction. We aimed to verify in vivo that gradual inflow obstructions, representing prepump thrombosis, are detectable by a pump-attached accelerometer, where the routine use of pump power (PLVAD) is deficient. METHOD In a porcine model (n = 8), balloon-tipped catheters obstructed HVAD inflow conduits by 34% to 94% in 5 levels. Afterload increases and speed alterations were conducted as controls. We computed nonharmonic amplitudes (NHA) of pump vibrations captured by the accelerometer for the analysis. Changes in NHA and PLVAD were tested by a pairwise nonparametric statistical test. Detection sensitivities and specificities were investigated by receiver operating characteristics with areas under the curves (AUC). RESULTS NHA remained marginally affected during control interventions, unlike PLVAD. NHA elevated during obstructions within 52-83%, while mass pendulation was most pronounced. Meanwhile, PLVAD changed far less. Increased pump speeds tended to amplify the NHA elevations. The corresponding AUC was 0.85-1.00 for NHA and 0.35-0.73 for PLVAD. CONCLUSION Elevated NHA provides a reliable indication of subclinical gradual inflow obstructions. The accelerometer can potentially supplement PLVAD for earlier warnings and localization of pump.
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Affiliation(s)
- Didrik Lilja
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
| | - Itai Schalit
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo, Norway
| | - Andreas Espinoza
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo, Norway
| | - Arnt Eltvedt Fiane
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway
| | - Gry Dahle
- Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway
| | - Helen Littorin-Sandbu
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo, Norway
| | - Fred-Johan Pettersen
- Department of Clinical and Biomedical Engineering, Oslo University Hospital, Oslo, Norway; Department of Physics, University of Oslo, Oslo, Norway
| | | | - Amrit P S Thiara
- Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway
| | - Ole Jakob Elle
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo, Norway; Department of Informatics, University of Oslo, Norway
| | - Per Steinar Halvorsen
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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Lilja D, Schalit I, Espinoza A, Pettersen FJ, Elle OJ, Halvorsen PS. Detection of inflow obstruction in left ventricular assist devices by accelerometer: An in vitro study. Med Eng Phys 2022; 110:103917. [PMID: 36564132 DOI: 10.1016/j.medengphy.2022.103917] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 11/01/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022]
Abstract
Inflow obstruction in left ventricular assist devices (LVAD) may lead to embolic stroke and pump malfunction. We investigated if an accelerometer detected graded LVAD inflow obstructions. Detection performances were compared to the current continuous surveillance routine based on the pump power consumption (PLVAD). In ten mock circuit experiments, four different-sized pendulating balloons obstructed HVAD™ inflow conduits cross-section areas by 14%-75%. Nonharmonic amplitudes (NHA) of continuous signals from a triaxial accelerometer attached to the LVAD were compared against single-point PLVAD values, using load and speed alterations as control interventions. We analyzed the NHA band power with a pairwise nonparametric statistical test. The detection performances were analyzed by receiver operating characteristics with areas under the curves (AUC). The NHA remained unaffected during load alterations. In contrast, NHA increased significantly from the 27% obstruction level (AUC≥0.82), an effect amplified by increased pump speed. PLVAD did not change significantly below the maximal 75% obstruction level (AUC≤0.36). In conclusion, NHA detected the inflow obstructions much better than PLVAD. The technique may provide a future monitoring modality of any pendulating obstructive inflow pathology.
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Affiliation(s)
- Didrik Lilja
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
| | - Itai Schalit
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Andreas Espinoza
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo Norway
| | - Fred-Johan Pettersen
- Department of Clinical and Biomedical Engineering, Oslo University Hospital, Oslo, Norway; Department of Physics, University of Oslo, Norway
| | - Ole Jakob Elle
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo Norway; Department of Informatics, The University of Oslo, Norway
| | - Per Steinar Halvorsen
- The Intervention Centre, Division of Technology and Innovation, Oslo University Hospital, Oslo Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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Improved Detection Of Thromboembolic Complications In Left Ventricular Assist Device By Novel Accelerometer-Based Analysis. ASAIO J 2022; 68:1117-1125. [DOI: 10.1097/mat.0000000000001654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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Sabbah MS, Rosenbaum AN, Behfar A. Listening for Thrombosis. Mayo Clin Proc 2021; 96:841-843. [PMID: 33814088 DOI: 10.1016/j.mayocp.2021.02.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 02/23/2021] [Indexed: 11/24/2022]
Affiliation(s)
- Michael S Sabbah
- Department of Cardiovascular Diseases, Van Cleve Cardiac Regenerative Medicine Program, Mayo Clinic, Rochester, MN
| | - Andrew N Rosenbaum
- von Liebig Center for Transplantation and Clinical Regeneration, Van Cleve Cardiac Regenerative Medicine Program, Mayo Clinic, Rochester, MN
| | - Atta Behfar
- Department of Cardiovascular Diseases, von Liebig Center for Transplantation and Clinical Regeneration, Department of Molecular Pharmacology and Experimental Therapeutics, Van Cleve Cardiac Regenerative Medicine Program, Mayo Clinic, Rochester, MN.
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Mainsah BO, Patel PA, Chen XJ, Olsen C, Collins LM, Karra R. Novel Acoustic Biomarker of Quality of Life in Left Ventricular Assist Device Recipients. J Am Heart Assoc 2021; 10:e018588. [PMID: 33660516 PMCID: PMC8174227 DOI: 10.1161/jaha.120.018588] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 01/08/2021] [Indexed: 12/18/2022]
Abstract
Background Although technological advances to pump design have improved survival, left ventricular assist device (LVAD) recipients experience variable improvements in quality of life. Methods for optimizing LVAD support to improve quality of life are needed. We investigated whether acoustic signatures obtained from digital stethoscopes can predict patient-centered outcomes in LVAD recipients. Methods and Results We followed precordial sounds over 6 months in 24 LVAD recipients (8 HeartWare HVAD™, 16 HeartMate 3 [HM3]). Subjects recorded their precordial sounds with a digital stethoscope and completed a Kansas City Cardiomyopathy Questionnaire weekly. We developed a novel algorithm to filter LVAD sounds from recordings. Unsupervised clustering of LVAD-mitigated sounds revealed distinct groups of acoustic features. Of 16 HM3 recipients, 6 (38%) had a unique acoustic feature that we have termed the pulse synchronized sound based on its temporal association with the artificial pulse of the HM3. HM3 recipients with the pulse synchronized sound had significantly better Kansas City Cardiomyopathy Questionnaire scores at baseline (median, 89.1 [interquartile range, 86.2-90.4] versus 66.1 [interquartile range, 31.1-73.7]; P=0.03) and over the 6-month study period (marginal mean, 77.6 [95% CI, 66.3-88.9] versus 59.9 [95% CI, 47.9-70.0]; P<0.001). Mechanistically, the pulse synchronized sound shares acoustic features with patient-derived intrinsic sounds. Finally, we developed a machine learning algorithm to automatically detect the pulse synchronized sound within precordial sounds (area under the curve, 0.95, leave-one-subject-out cross-validation). Conclusions We have identified a novel acoustic biomarker associated with better quality of life in HM3 LVAD recipients, which may provide a method for assaying optimized LVAD support.
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Affiliation(s)
- Boyla O. Mainsah
- Department of Electrical and Computer EngineeringDuke UniversityDurhamNC
| | | | - Xinlin J. Chen
- Department of Electrical and Computer EngineeringDuke UniversityDurhamNC
| | - Cameron Olsen
- Division of CardiologyDepartment of MedicineDuke University Medical CenterDurhamNC
| | - Leslie M. Collins
- Department of Electrical and Computer EngineeringDuke UniversityDurhamNC
| | - Ravi Karra
- Division of CardiologyDepartment of MedicineDuke University Medical CenterDurhamNC
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Moscato F, Gross C, Maw M, Schlöglhofer T, Granegger M, Zimpfer D, Schima H. The left ventricular assist device as a patient monitoring system. Ann Cardiothorac Surg 2021; 10:221-232. [PMID: 33842216 DOI: 10.21037/acs-2020-cfmcs-218] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Technological progress of left ventricular assist devices (LVADs) towards rotary blood pumps and the optimization of medical management contributed to the significant improvements in patient survival as well as LVAD support duration. Even though LVAD therapy is now well-established for end-stage heart failure patients, the long-term occurrence of adverse events (AE) such as bleeding, infection or stroke, still represent a relevant burden. An early detection of AE, before onset of major symptoms, can lead to further optimization of patient treatment and thus mitigate the burden of AE. Continuous patient monitoring facilitates identification of pathophysiological states and allows anticipation of AE to improve patient management. In this paper, methods, algorithms and possibilities for continuous patient monitoring based on LVAD data are reviewed. While experience with continuous LVAD monitoring is currently limited to a few centers worldwide, the pace of developments in this field is fast and we expect these technologies to have a global impact on the well-being of LVAD patients.
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Affiliation(s)
- Francesco Moscato
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria.,Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Christoph Gross
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
| | - Martin Maw
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria.,Division of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Thomas Schlöglhofer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria.,Division of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Marcus Granegger
- Division of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Daniel Zimpfer
- Division of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Heinrich Schima
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria.,Division of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
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Chen XJ, LaPorte ET, Olsen C, Collins LM, Patel P, Karra R, Mainsah BO. Heart Sound Analysis in Individuals Supported With Left Ventricular Assist Devices. IEEE Trans Biomed Eng 2021; 68:3009-3018. [PMID: 33606625 DOI: 10.1109/tbme.2021.3060718] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE LVADs are surgically implanted mechanical pumps that improve survival rates of individuals with advanced heart failure. LVAD therapy is associated with high morbidity, which can be partially attributed to challenges with detecting LVAD complications before adverse events occur. Current methods used to monitor for complications with LVAD support require frequent clinical assessments at specialized LVAD centers. Analysis of recorded precordial sounds may enable real-time, remote monitoring of device and cardiac function for early detection of LVAD complications. The dominance of LVAD sounds in the precordium limits the utility of routine cardiac auscultation of LVAD recipients. In this work, we develop a signal processing pipeline to mitigate sounds generated by the LVAD. METHODS We collected in vivo precordial sounds from 17 LVAD recipients, and contemporaneous echocardiograms from 12 of these individuals, to validate heart valve closure timings. RESULTS We characterized various acoustic signatures of heart sounds extracted from in vivo recordings, and report preliminary findings linking fundamental heart sound characteristics and level of LVAD support. CONCLUSION Mitigation of LVAD sounds from precordial sound recordings of LVAD recipients enables analysis of intrinsic heart sounds. SIGNIFICANCE These findings provide proof-of-concept evidence of the clinical utility of heart sound analysis for bedside and remote monitoring of LVAD recipients.
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