Mild to Moderate Atheromatous Disease of the Thoracic Aorta and New Ischemic Brain Lesions After Conventional Coronary Artery Bypass Graft Surgery

Stroke outcomes following cardiac and aortic surgery are improved by the involvement of a stroke team

OBJECTIVES

Post-cardiac and aortic surgery stroke is often underreported. We detail our single-centre experience the following introduction of comprehensive consultant-led daily stroke service, to demonstrate the efficacy of a stroke team in recovery from stroke following cardiac and aortic surgeries.

METHODS

This retrospective, single-centre observational cohort study analysed consecutive patients undergoing cardiac and aortic surgery at our institution from August 2014 to December 2020. Main outcomes included stroke rate, predictors of stroke, and neurological deficit resolution or persistence at discharge and clinic follow-up.

RESULTS

A total of 12,135 procedures were carried out in the reference period. Among these, 436 (3.6%) suffered a stroke. Overall survival to discharge and follow-up were 86.0% and 84.0% respectively. Independent risk factors for post-operative stroke included advanced age (OR 1.033, 95% CI [1.023, 1.044], p < .001), female sex (OR 1.491, 95% [1.212, 1.827], p < .001), history of previous cardiac surgeries (OR 1.670, 95% CI [1.239, 2.218], p < .001), simultaneous coronary artery bypass graft + valve procedures (OR 1.825, 95% CI [1.382, 2.382], p < .001) and CPB time longer than 240 min (OR 3.384, 95% CI [2.413, 4.705], p < .001). Stroke patients managed by the multidisciplinary team demonstrated significantly higher rates of survival at discharge (87.3% vs. 61.9%, p = .001).

CONCLUSIONS

Perioperative stroke can be debilitating immediately long term. The involvement of specialist stroke teams plays a key role in reducing the long-term burden and mortality of this condition.

Choosing transcatheter aortic valve replacement in porcelain aorta: outcomes versus surgical replacement

OBJECTIVES

Porcelain aorta complicates aortic valve replacement and is an indication for transcatheter approaches. No study has compared surgical and transcatheter valve replacement in the setting of porcelain aorta. We characterize porcelain aorta patients undergoing aortic valve replacement and the association of aortic calcification and outcomes.

METHODS

Patients undergoing aortic valve replacement with porcelain aorta were identified. Aortic calcium volume was determined using 3D computed tomography thresholding techniques. Propensity scoring was performed to assess the effect of surgical versus transcatheter approaches. Risk factors for composite major hospital complications (death, stroke and dialysis) were identified using random forest machine learning.

RESULTS

From January 2006 to January 2015, 164 patients with porcelain aorta underwent aortic valve replacement [105 (64%) surgical replacement, 59 (36%) transcatheter replacement]. Propensity scoring matched 29 pairs (49% of transcatheter patients). Before matching, 5-year survival was 41% [(43% surgical, 35% transcatheter, P(log-rank) = 0.9]. After matching, mortality for surgical versus transcatheter replacement was 3.4% (n = 1) vs 10% (n = 3), stroke 14% (n = 4) vs 3.4% (n = 1) and dialysis 6.9% (n = 2) versus 11% (n = 3). Matched 5-year survival was 40% after surgical replacement and 29% after transcatheter replacement [P(log-rank) = 0.4]. Total aortic calcium volume was greater in transcatheter than surgical patients [18 (8.0) vs 17 (7.7) ml] and was associated with more major hospital complications after either approach.

CONCLUSIONS

Surgical and transcatheter approaches are complementary options for aortic stenosis with porcelain aorta. Surgical valve replacement remains an effective treatment for patients requiring concomitant procedures. Quantifying aortic calcium volume is a helpful risk predictor in all patients with porcelain aorta.

Acute Infarcts on Brain MRI Following Aortic Arch Repair With Circulatory Arrest: Insights From the ACE CardioLink-3 Randomized Trial

BACKGROUND

to investigate the frequency and distribution of new ischemic brain lesions detected by diffusion-weighted imaging on brain magnetic resonance imaging after aortic arch surgery.

METHODS

This preplanned secondary analysis of the randomized, controlled ACE (Aortic Surgery Cerebral Protection Evaluation) CardioLink-3 trial compared the safety and efficacy of innominate versus axillary artery cannulation during elective proximal aortic arch surgery. Participants underwent pre and postoperative magnetic resonance imaging. New ischemic lesions were defined as lesions visible on postoperative, but not preoperative diffusion weighted imaging.

RESULTS

Of the 111 trial participants, 102 had complete magnetic resonance imaging data. A total of 391 new ischemic lesions were observed on diffusion-weighted imaging in 71 (70%) patients. The average number of lesions in patients with ischemic lesion were 5.5±4.9 with comparable numbers in the right (2.9±2.0) and left (3.0±2.3) hemispheres (P=0.49). Half the new lesions were in the middle cerebral artery territory; 63% of the cohort had ischemic lesions in the anterior circulation, 49% in the posterior circulation, 42% in both, and 20% in watershed areas. A probability mask of all diffusion-weighted imaging lesions revealed that the cerebellum was commonly involved. More severe white matter hyperintensity on preoperative magnetic resonance imaging (odds ratio, 1.80 [95% CI, 1.10-2.95]; P=0.02) and lower nadir nasopharyngeal temperature during surgery (odds ratio per 1°C decrease, 1.15 [95% CI, 1.00-1.32]; P=0.05) were associated with the presentation of new ischemic lesion; older age (risk ratio per 1-year increase, 1.02 [95% CI, 1.00-1.04]; P=0.03) and lower nadir temperature (risk ratio per 1°C decrease, 1.06 [95% CI, 1.00-1.14]; P=0.06) were associated with greater number of lesions.

CONCLUSIONS

In patients who underwent elective proximal aortic arch surgery, new ischemic brain lesions were common, and predominantly involved the middle cerebral artery territory or cerebellum. Underlying small vessel disease, lower temperature nadir during surgery, and advanced age were risk factors for perioperative ischemic lesions.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02554032.

Silent Brain Infarction, Delirium, and Cognition in Three Invasive Cardiovascular Procedures: a Systematic Review

Silent brain infarctions (SBIs) are brain lesions noted on neuroimaging that are not associated with clinical symptoms. SBIs are associated with a number of vascular risk factors and are common following invasive cardiovascular procedures such as atrial fibrillation (AF) ablation, coronary artery bypass graft (CABG), and transcatheter aortic valve replacement (TAVR). Although not eliciting signs of clinical stroke, SBIs are associated with increased frailty, and motor and mood features. Less is known, however, about the relationship between SBI, cognition, and delirium following invasive cardiac procedures and most investigations into these relationships have been reported in large-scale epidemiological studies. In the current paper, we conducted a systematic review to evaluate evidence of a relationship between SBI, delirium, and cognitive decline following CABG, AF ablation, and TAVR. Twenty studies met inclusion criteria. In general, our review identified conflicting results for each cardiac procedure, with some studies suggesting a relationship between SBI, cognitive impairment, and delirium, whereas others showed no relationship between SBI, cognitive impairment, and delirium. Potential reasons for this discrepancy as well as suggestions for future research are discussed.

2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The guideline for coronary artery revascularization replaces the 2011 coronary artery bypass graft surgery and the 2011 and 2015 percutaneous coronary intervention guidelines, providing a patient-centric approach to guide clinicians in the treatment of patients with significant coronary artery disease undergoing coronary revascularization as well as the supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from May 2019 to September 2019, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, CINHL Complete, and other relevant databases. Additional relevant studies, published through May 2021, were also considered.

STRUCTURE

Coronary artery disease remains a leading cause of morbidity and mortality globally. Coronary revascularization is an important therapeutic option when managing patients with coronary artery disease. The 2021 coronary artery revascularization guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with coronary artery disease who are being considered for coronary revascularization, with the intent to improve quality of care and align with patients' interests.

Neuroprotective effects of dynamic bubble trap use in patients undergoing pulmonary endarterectomy: a two-arm randomized controlled trial

Background

During cardiosurgical procedures that use extracorporeal circulation (ECC), a variety of neurological complications can occur, and postoperative cognitive deficits remain an unsolved problem. Among the sources of these complications are intraoperatively detectable cerebral microemboli, which mainly consist of air. This study's purpose was to assess neuroprotective effects of reducing these gaseous microemboli using a dynamic bubble trap (DBT) in patients undergoing pulmonary endarterectomy (PEA) for the treatment of chronic thromboembolic pulmonary hypertension (CTEPH).

Methods

Patients undergoing PEA were randomly assigned to receive either a DBT (n=47) or no additional device (controls, n=46) during ECC. Neuropsychological testing was performed before and 3 months after PEA. The primary endpoint was cognitive improvement in the DBT group (n=29) compared with the control group (n=42). As secondary endpoint, ischemic brain micro-lesions were analyzed on postoperative days 6 through 10 using diffusion-weighted magnetic resonance imaging (MRI).

Results

Analysis of interaction effects revealed improved performance in visual long-term memory (P=0.008, η²=0.099), verbal long-term memory (P=0.030, η²=0.067), verbal short-term memory (P=0.014, η²=0.083), and attention and processing speed (P=0.043, η²=0.056) from pre- to post-testing in the DBT group compared to control group. In MRI, postoperative ischemic micro-lesions could only be detected in one patient; another patient suffered a severe bihemispheric embolic stroke.

Conclusions

DBT positively influences memory function after PEA. This effect is most likely caused by the reduction of gaseous microemboli.

Trial Registration

This study is registered in the German Clinical Trials Register, ID: DRKS00021499.

Incidence and Risk Factors for Silent Brain Infarction After On-Pump Cardiac Surgery: A Meta-analysis and Meta-regression of 29 Prospective Cohort Studies

BACKGROUND

Silent brain infarction (SBI) happens at a considerable rate after on-pump cardiac surgery. Though termed silent, SBI is related to unfavorable clinical outcomes including higher incidence of future stroke and neurocognitive impairment in the general population. The risk factors of SBI have not been fully identified in both individual studies and several meta-analyses addressing the topic. In this meta-analysis, we aimed to conduct meta-regression analysis for the first time to explore risk factors for SBI after on-pump cardiac surgery.

METHODS

This meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Medline, Embase, Central, Web of Science, and Wiley databases were searched for relevant studies. Preoperative patient baseline characteristics and intraoperative surgical parameters were extracted from included studies. For meta-regression, a P value of less than 0.1 was considered statistically significant in both univariable and multivariable analyses.

RESULTS

Twenty-nine studies with 1478 patients were included in this meta-analysis. The summarized SBI rate after on-pump cardiac surgery was 37% (95% CI 0.27-0.47, P < 0.0001). Heterogeneity between studies was significant (I2 = 94.9%, P < 0.0001). In multivariable meta-regression, we found that age (coefficient 0.014, 95% CI 0.001-0.029, P = 0.043), diabetes (coefficient 0.006, 95% CI - 0.001 to 0.013, P = 0.075), and proportion of CABG (coefficient - 0.001, 95% CI - 0.003 to 0.0003, P = 0.096) were significantly associated with SBI incidence.

CONCLUSION

From the meta-regression, we concluded that advanced age and diabetes were related to increased SBI incidence after on-pump cardiac surgery, while CABG procedure alone was associated with less SBI onset. Studies with more accurate diagnoses of SBI are required to add more conclusive evidence to the field.

Factors associated with delirium after cardiac surgery: A prospective cohort study

Background:

Delirium is a frequent complication after cardiac surgery and is associated with a higher incidence of morbidity and mortality and a prolonged hospital stay. However, knowledge of the variables involved in its occurrence is still limited; therefore, in this study, we evaluated the perioperative risk factors independently associated with this complication.

Methods:

This study was conducted in a referral tertiary care university hospital with a cardiovascular focus. A total of 311 consecutive adult patients undergoing any type of cardiac surgery were evaluated. The subjects were examined at regular intervals in the postoperative period using the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) tool.

Results:

The incidence of postoperative delirium (PD) was 10%. Among the 18 pre-, intra- and postoperative variables evaluated, the logistic regression analysis showed that low education level, history of diabetes or stroke, type of surgery, prolonged extracorporeal circulation, or red blood cell transfusion in the intra- or postoperative period were independently associated with delirium after cardiac surgery. An increased body mass index was identified as a protective factor.

Conclusions:

The aforementioned risk factors are significantly and independently associated with the presentation of PD. Because some of these factors can be treated or avoided, the results of this study are highly relevant to reduce the risk of this complication and improve the care of patients undergoing cardiac surgery.

Perioperative covert stroke in patients undergoing coronary artery bypass graft surgery

Objectives

Covert stroke is a complication of coronary artery bypass graft surgery that is increasingly recognized as a serious problem. In noncardiac surgery settings, covert stroke is associated with the development of delirium, long-term cognitive decline, and future clinical stroke. Therefore, we sought to determine the feasibility of conducting a large, prospective cohort study of the influence of covert stroke on neurocognitive outcomes in patients undergoing coronary artery bypass graft surgery.

Methods

NeuroVISION Cardiac pilot was a prospective cohort study enrolling patients aged ≥21 years undergoing isolated coronary artery bypass graft surgery to receive diffusion-weighted magnetic resonance imaging of the brain after surgery to identify patients with covert stroke. Patients were screened for postoperative delirium in-hospital and were administered questionnaires of cognitive and global function (once before and twice after surgery). Regional cerebral oxygen saturation was recorded during surgery using near-infrared spectroscopy.

Results

Between March 27, 2017, and February 11, 2018, 50 of 66 patients enrolled (76%) completed the brain magnetic resonance imaging (1 patient per week). Among the 49 patients included in the analysis, 19 (39%; 95% confidence interval, 26%-53%) experienced perioperative covert stroke and 3 (6%) had a clinical stroke within 30 days of surgery. Postoperative delirium occurred in 5 (26%) patients with covert stroke and in 3 (10%) patients who did not experience covert stroke.

Conclusions

The NeuroVISION Cardiac pilot study established the feasibility of conducting a large, prospective cohort study of the determinants and consequences of covert stroke in patients undergoing coronary artery bypass graft surgery.

Silent Brain Infarcts Following Cardiac Procedures: A Systematic Review and Meta-Analysis

Background

Silent brain infarcts (SBI) are increasingly being recognized as an important complication of cardiac procedures as well as a potential surrogate marker for studies on brain injury. The extent of subclinical brain injury is poorly defined.

Methods and Results

We conducted a systematic review and meta‐analysis utilizing studies of SBIs and focal neurologic deficits following cardiac procedures. Our final analysis included 42 studies with 49 separate intervention groups for a total of 2632 patients. The prevalence of SBIs following transcatheter aortic valve implantation was 0.71 (95% CI 0.64‐0.77); following aortic valve replacement 0.44 (95% CI 0.31‐0.57); in a mixed cardiothoracic surgery group 0.39 (95% CI 0.28‐0.49); coronary artery bypass graft 0.25 (95% CI 0.15‐0.35); percutaneous coronary intervention 0.14 (95% CI 0.10‐0.19); and off‐pump coronary artery bypass 0.14 (0.00‐0.58). The risk ratio of focal neurologic deficits to SBI in aortic valve replacement was 0.22 (95% CI 0.15‐0.32); in off‐pump coronary artery bypass 0.21 (95% CI 0.02‐2.04); with mixed cardiothoracic surgery 0.15 (95% CI 0.07‐0.33); coronary artery bypass graft 0.10 (95% CI 0.05‐0.18); transcatheter aortic valve implantation 0.10 (95% CI 0.07‐0.14); and percutaneous coronary intervention 0.06 (95% CI 0.03‐0.14). The mean number of SBIs per patient was significantly higher in the transcatheter aortic valve implantation group (4.58 ± 2.09) compared with both the aortic valve replacement group (2.16 ± 1.62, P=0.03) and the percutaneous coronary intervention group (1.88 ± 1.02, P=0.03).

Conclusions

SBIs are a very common complication following cardiac procedures, particularly those involving the aortic valve. The high frequency of SBIs compared with strokes highlights the importance of recording this surrogate measure in cardiac interventional studies. We suggest that further work is required to standardize reporting in order to facilitate the use of SBIs as a routine outcome measure.

Multi-arterial and total-arterial coronary revascularization: Past, present, and future perspective

BACKGROUND AND AIM OF THE STUDY

Although abundant biological, clinical, and scientific evidence exists on the superiority of multi-arterial (MAR) and total-arterial revascularization (TAR) over the conventional strategy with a single internal thoracic artery, only 10% of patients undergoing coronary artery bypass grafting (CABG) in the United States receives a second arterial conduit, and only 5% of patients receives TAR.

METHODS AND RESULTS

In January 2020, the authors performed comprehensive search to identify studies that evaluated MAR and TAR strategies through the MEDLINE database.

CONCLUSIONS

In this paper, the authors reviewed the literature on the historical and current evidence in favor of MAR and TAR, thus underlying why current CABG practice needs qualitative improvement.

Aortic calcifications on routine preoperative chest X-ray and perioperative stroke during cardiac surgery: a nested matched case-control study

OBJECTIVES

Perioperative stroke in cardiac surgery is most often embolic in origin. Preoperative chest X-ray (CXR) is routinely used amongst others to screen for relevant aortic calcification, a potential source of embolic stroke. We performed a nested matched case-control study to examine the relationship between aortic calcifications on CXR and the occurrence of embolic stroke.

METHODS

Among all consecutive patients undergoing cardiac surgery in our hospital between January 2014 and July 2017, we selected all patients with perioperative embolic stroke (cases). Controls, all patients without perioperative stroke, were matched on age, sex and type of surgery. All preoperative CXRs were scored for aortic calcifications (none, mild, severe) in the ascending aorta, arch, aortic knob and descending aorta.

RESULTS

Out of the 3038 eligible patients, 27 cases were detected and 78 controls were selected. In the stroke group, mild-to-severe calcifications were found least often in the ascending aorta [9% of patients, 95% confidence interval (CI) 1-29%] and most frequently in the aortic knob (63% of patients, 95% CI 44-78%). The distribution of aortic calcification was comparable in cases versus controls.

CONCLUSIONS

Calcification burden was comparable between the cases and their matched controls. In our study population, CXR findings on aortic calcification were not related to the risk of embolic stroke. In these patients, the correlation between findings on the preoperative CXR and the risk of stroke might, therefore, be too weak to use the CXR directly for the assessment of the safety of manipulating the ascending aorta during surgery.

Numerical Investigation of Blood Flow Characteristics through Cannulated Aorta

Cannulation of the aorta is done in order to provide oxygenation and circulatory function through the use of the heart lung machine during cardio-pulmonary bypass (CPB). The nature of the blood flow through the aorta and its ramifications during CPB is mostly linear as compared to the physiological flow, which is pulsatile in nature. This leads to the development of multiple morbidities caused by the development of emboli and atheromas. Perioperative postoperative care is necessitated by these conditions. As such the understanding of the blood flow characteristics is necessitated in order to effectively prevent the formation of emboli and to prevent the "Sandblasting" effect. The authors in this work seek to investigate the nature of blood flow through the aorta under such circumstances. The results obtained show the nature of blood flow in the cannulated aorta as well as the optimum angle of placement of the cannula with respect to the aortic wall.

Impact of Aortic Atherosclerosis Burden on Outcomes of Surgical Aortic Valve Replacement

BACKGROUND

Epiaortic ultrasound detects and localizes ascending aortic atherosclerosis. In this analysis we investigated the association between epiaortic ultrasound-based atheroma grade during surgical aortic valve replacement (SAVR) and perioperative adverse outcomes.

METHODS

SAVR patients in a randomized trial of 2 embolic protection devices underwent a protocol-defined 5-view epiaortic ultrasound read at a core laboratory. Aortic atherosclerosis was quantified with the Katz atheroma grade, and patients were categorized as mild (grade I-II) or moderate/severe (grade III-V). Multivariable logistic regression was used to estimate associations between atheroma grade and adverse outcomes, including death, clinically apparent stroke, cerebral infarction on diffusion-weighted magnetic resonance imaging, delirium, and acute kidney injury (AKI) by 7 and 30 days.

RESULTS

Precannulation epiaortic ultrasound data were available for 326 of 383 randomized patients (85.1%). Of these, 106 (32.5%) had moderate/severe Katz atheroma grade at any segment of the ascending aorta. Although differences in the composite of death, stroke, or cerebral infarction on diffusion-weighted magnetic resonance imaging by 7 days were not statistically significant, moderate/severe atheroma grade was associated with a greater risk of AKI by 7 days (adjusted odds ratio, 2.63; 95% confidence interval, 1.24-5.58; P = .01). At 30 days, patients with moderate/severe atheroma grade had a greater risk of death, stroke, or AKI (adjusted odds ratio, 1.97; 95% confidence interval, 1.04-3.71; P = .04).

CONCLUSIONS

Moderate/severe aortic atherosclerosis was associated with an increased risk of adverse events after SAVR. Epiaortic ultrasound may serve as a useful adjunct for identifying patients who may benefit from strategies to reduce atheroembolic complications during SAVR.

Distribution of Thoracic Aortic Calcifications in Patients Undergoing Coronary Artery Bypass Grafting

Background

In procedures involving surgical maneuvers such as cannulation, clamping, or proximal anastomosis where aortic manipulation is inevitable, a preliminary assessment of atherosclerotic plaques bears clinical significance. In the present study, our aim was to evaluate the frequency and distribution of aortic calcifications in patients undergoing coronary artery bypass grafting (CABG) surgery to propose a morphological classification system.

Methods

A total of 443 consecutive patients with coronary artery disease were included in this study. Preoperative non-contrast enhanced computed tomography images, in-hospital follow-up data, and patient characteristics were retrospectively evaluated.

Results

Whereas 33% of patients had no calcifications at any site in the aorta, 7.9%, 75.4%, and 16.7% had calcifications in the ascending aorta, aortic arch, and descending aorta, respectively. Focal small calcifications were the most common type of lesions in the ascending aorta (3.9%), whereas 9 patients (1.4%) had porcelain ascending aorta. We defined four types of patients with increasing severity and extent of calcifications.

Conclusions

Based on the frequency and distribution of calcifications in the thoracic aorta, we propose a classification system from least to most severe for coronary artery disease patients who are candidates for CABG.

Implementation of the aortic no-touch technique to reduce stroke after off-pump coronary surgery

OBJECTIVES

Despite substantial scientific effort, the relationship between stroke after coronary artery bypass grafting and the use of the aortic no-touch off-pump technique (anOPCAB) remains incompletely understood. The present study aimed to define the effect of anOPCAB on the occurrence and time point of stroke.

METHODS

A total cohort of 15,042 consecutive patients underwent surgical myocardial revascularization at a single institution. After establishing anOPCAB as routine procedure, 4695 patients received surgery by 18 different surgeons using the anaortic approach. After the exclusion of all patients with cardiogenic shock and "side-clamp" off-pump coronary artery bypass grafting, 13,279 patients (4485 with anOPCAB) were included in the study. Perioperative strokes were classified as strokes occurring during the hospital stay, with early strokes observed immediately after emergence from anesthesia (vs delayed strokes).

RESULTS

The anOPCAB technique reduced the postoperative stroke rate to 0.49% versus 1.31% in on-pump patients (P < .0001). The overall stroke rate after adoption of anOPCAB (0.64%) decreased compared with before its adoption (1.40%; P < .0001). With anOPCAB, the risk of early strokes virtually disappeared to 4 of 4485 patients (0.09%; 95% confidence interval, 0.00-0.18% vs 0.83% in on-pump patients; P < .0001), whereas the incidence of delayed strokes was not affected (0.40% vs 0.48%; P = .5181). The key results were confirmed after adjustment using propensity score-based analyses.

CONCLUSIONS

The anOPCAB technique with avoidance of any aortic manipulation is an effective tool to minimize the risk of early strokes during coronary artery bypass grafting, and thus, should be considered as a routine approach. In contrast, additional preventive strategies against delayed strokes remain to be elaborated.

Does epiaortic ultrasound screening reduce perioperative stroke in patients undergoing coronary surgery? A topical review

Although the occurrence of stroke in patients undergoing coronary artery bypass grafting (CABG) is decreasing, it remains an important concern. Therefore, it is important to identify and adopt strategies that can decrease the incidence of stroke in these patients. One of the strategies that have demonstrated the potential to decrease the rate of post-CABG stroke is an assessment of aorta for atherosclerosis before surgery and changing the surgical plan accordingly to minimize the stroke risk. This assessment can be done through palpation of the aorta, transesophageal echocardiography (TEE), and epiaortic ultrasound scanning (EAS). EAS has shown superiority over both palpation and TEE for intraoperative evaluation of aorta. However, despite the evidence demonstrating reduced stroke rates with the EAS-guided approach, EAS is not yet the standard of care procedure in patients undergoing CABG. Therefore, we have reviewed the literature for evidence that supports the routine use of EAS in patients undergoing coronary surgery and have presented solutions to overcome the barriers to its routine use.

Impact of Modified Transesophageal Echocardiography on Mortality and Stroke after Cardiac Surgery: A Large Cohort Study

The aim of this study was to investigate the impact of perioperative screening with modified transesophageal echocardiography (A-View method). We compared, in consecutive patients who underwent cardiac surgery between 2006 and 2014, 30-day mortality and in-hospital stroke incidence, operated either with perioperative modified TEE screening (intervention group) or only with conventional TEE screening (control group). Of the 8,605 study patients, modified TEE was applied in 1,391 patients (16.2%). Patients in the intervention group were on average older (71 versus 68 years, p < 0.001) and more often females (31.0% versus 28.0%, p < 0.001) and had a higher predicted mortality (EuroSCORE I: 5.9% versus 4.0%, p < 0.001). The observed 30-day mortality was 2.2% and 2.5% in both groups, respectively, with multivariable and propensity-score adjusted relative risks (RRs) of 0.70 (95% CI: 0.50–1.00, p = 0.05) and 0.67 (95% CI: 0.45–0.98, p = 0.04). In-hospital stroke was 2.9% and 2.1% in both groups, respectively, with adjusted RRs of 1.03 (95% CI: 0.73–1.45) and 1.01 (95% CI: 0.71–1.43). In patients undergoing cardiac surgery, use of perioperative screening for aortic atherosclerosis with modified TEE was associated with lower postoperative mortality, but not stroke, as compared to patients operated on without such screening.

Sutureless aortic valve implantation in patient with porcelain aorta via unclamped aorta and deep hypothermic circulatory arrest

Severe atherosclerotic calcification of the ascending aorta, the so-called porcelain aorta, precludes cardiac surgeons from placing an aortic cross-clamp and direct aortic cannulation due to the increased risk of systemic embolism and stroke. In the present report, we support the option of sutureless valve implantation in a case of a porcelain ascending aorta, with deep hypothermic circulatory arrest and also without aortic cross-clamp.

Aortic Arch Atheroma: Stroke Reduction in Cardiac Surgical Patients

Cardiac surgery is increasingly performed on elderly patients with extensive coronary artery abnormalities who have impaired left ventricular function, decreased physiologic reserve, and multiple comorbid conditions. Considerable numbers of these patients develop perioperative neurologic complications ranging from subtle cognitive dysfunction to more evident postoperative confusion, delirium, and, less commonly, clinically apparent stroke. Magnetic resonance imaging studies have elucidated that a considerable number of patients have new ischemic brain infarcts, particularly after conventional coronary artery bypass graft surgery. Mechanisms of cerebral injury during and after cardiac surgery are discussed. Intraoperative transesophageal echocardiography and epiaortic scanning for detection of atheromatous disease of the proximal thoracic aorta is paramount in identifying patients at high risk from neurologic injury. It is important to recognize that our efforts to minimize neurologic injury should not be limited to the intraoperative period. Particular efforts should be directed to temperature management, glycemia control, and pharmacologic neuroprotection extending into the postoperative period. Preoperative magnetic resonance angiography may be of value for screening patients with significant atheroma of the proximal thoracic aorta. It is likely that for patients with no significant atheromatous disease, conventional coronary artery revascularization is the most effective long-term strategy, whereas patients with atheromatous thoracic aorta may be better managed with beating heart surgery, hybrid techniques, or medical therapy alone. Patient stratification based on the aortic atheromatic burden should be addressed in future trials designed to tailor treatment strategies to improve long-term outcomes of coronary heart disease and reduce the risks of perioperative neurologic injury.

Coronary artery bypass grafting for left main disease and the risk of stroke: Incidence, aetiology and prevention

This review explores the association between left main disease and the increased risk of perioperative stroke following coronary artery bypass grafting, specifically addressing the potential underlying mechanisms and its potential prevention. In particular, this correlation appears stronger for patients with left main disease when compared to patients with isolated triple vessel disease. Even though evidence on this topic is limited and of modest quality, there appears to be a significant association between ascending aorta atherosclerosis and coronary artery disease. Furthermore, there seems to be a relationship between the severity and extent of carotid artery stenosis and coronary artery disease. Carotid artery disease is itself associated with atherosclerosis of the ascending aorta, a well-recognised risk factor for postoperative atheroembolic stroke. The association between left main disease, ascending aorta atherosclerosis and carotid artery stenosis may reflect an increased systemic atherosclerotic burden and hence explain, at least partially, the higher risk of perioperative cerebrovascular events. Potential pre-, intra- and post-operative strategies for stroke prevention are discussed.

Pathogenesis and Risk Factors for Cerebral Infarct After Surgical Aortic Valve Replacement

BACKGROUND AND PURPOSE

Stroke is a potentially devastating complication of cardiac surgery. Identifying predictors of radiographic infarct may lead to improved stroke prevention for surgical patients.

METHODS

We reviewed 129 postoperative brain magnetic resonance imagings from a prospective study of patients undergoing surgical aortic valve replacement. Acute infarcts were classified as watershed or embolic using prespecified criteria.

RESULTS

Acute infarct on magnetic resonance imaging was seen in 79 of 129 patients (61%), and interrater reliability for stroke pathogenesis was high (κ=0.93). Embolic infarcts only were identified in 60 patients (46%), watershed only in 2 (2%), and both in 17 (13%). In multivariable logistic regression, embolic infarct was associated with aortic arch atheroma (odds ratio [OR], 3.4; 95% confidence interval [CI], 1.0-12.0; P=0.055), old subcortical infarcts (OR, 5.5; 95% CI, 1.1-26.6; P=0.04), no history of percutaneous transluminal coronary angioplasty or coronary artery bypass graft (OR, 4.0; 95% CI, 1.2-13.7; P=0.03), and higher aortic valve gradient (OR, 1.3 per 5 mm Hg; 95% CI, 1.09-1.6; P=0.004). Watershed infarct was associated with internal carotid artery stenosis ≥70% (OR, 11.7; 95% CI, 1.8-76.8; P=0.01) and increased left ventricular ejection fraction (OR, 1.6 per 5% increase; 95% CI, 1.08-2.4; P=0.02).

CONCLUSIONS

The principal mechanism of acute cerebral infarction after aortic valve replacement is embolism. There are distinct factors associated with watershed and embolic infarct, some of which may be modifiable.

Imaging Techniques for Diagnosis of Thoracic Aortic Atherosclerosis

The most severe complications after cardiac surgery are neurological complications including stroke which is often caused by emboli merging from atherosclerosis in the ascending aorta to the brain. Information about the thoracic aorta is crucial in reducing the embolization risk for both surgical open and closed chest procedures such as transaortic heart valve implantation. Several techniques are available to screen the ascending aorta, for example, transesophageal echocardiography (TEE), epiaortic ultrasound, TEE A-view method, manual palpation, computed tomography, and magnetic resonance imaging. This paper provides a description of the advantages and disadvantages of these imaging techniques.

Cognitive Dysfunction, Delirium, and Stroke in Cardiac Surgery Patients

Neurologic injury in the form of cognitive decline, delirium, and stroke are common phenomena in patients undergoing cardiac surgery and continues to be one of the most common complication after cardiac surgery, in spite of improvements in mortality and and improved surgical and anesthetic techniques. These complications lead to a significant increase in length of stay in the intensive care unit, increased length of hospital admission, and functional impairment, resulting in not only profound negative effects on patients who experience these complications, but also to increased costs of medical care and delivery. We discuss each of these complications in regard to their risks factors, incidence, potential therapeutic modalities, and relevant intraoperative and postoperative considerations.

The Presence of New MRI Lesions and Cognitive Decline After Cardiac Surgery: A Systematic Review

Patients are commonly reported to experience postoperative cognitive decline (POCD) and new ischemic lesions following surgery, which many researchers have hypothesised to result from emboli entering the cerebral circulation during surgery. Modern magnetic resonance imaging techniques have enabled clear and accurate identification of ischemic lesions. However, difficulties in assessing subtle changes in cognitive impairment clinically remain. The purpose of this systematic review is to discuss the literature that has investigated cognitive outcome in relation to new ischaemic brain lesions after cardiac surgery.

Risk factors of atheromatous aorta in cardiovascular surgery

Objective

To determine the prevalence and profile of ascending aorta or aortic arch atheromatous disease in cardiovascular surgery patients, its risk factors and its prognostic implication early after surgery.

Methods

Between January 2007 and June 2011, 2042 consecutive adult patients were analyzed, with no exclusion criteria. Atheromatous aorta diagnosis was determined intraoperatively by surgeon palpation of the aorta. Determinants of atheromatous aorta, as well as its prognostic implication were studied by multivariate logistic regression.

Results

Prevalence of atheromatous aorta was 3.3% (68 patients). Determinants were age > 61 years (OR= 2.79; CI95%= 2.43 - 3.15; P<0.0001), coronary artery disease (OR=3.1; CI95%=2.8 - 3.44; P=0.002), hypertension (OR=2.26; CI95%=1.82 - 2.7; P=0.03) and peripheral vascular disease (OR=3.15; CI95%= 2.83 - 3.46; P=0.04). Atheromatous aorta was an independent predictor of postoperative cerebrovascular accident (OR=3.46; CI95%=3.18 - 3.76; P=0.01).

Conclusion

Although infrequent, the presence of atheromatous aorta is associated with advanced age, hypertension, coronary artery disease and peripheral vascular disease. In those patients, a more detailed preoperative and intraoperative assessment of the aorta is justified, due to greater risk of postoperative cerebrovascular accident.

Use of Blood Products and Diseased Ascending Aorta Are Determinants of Stroke After Off-Pump Coronary Artery Bypass Grafting

OBJECTIVE

To examine the effect of blood products on the occurrence of stroke after coronary artery surgery.

DESIGN

Institutional retrospective analysis.

SETTING

University hospital.

PARTICIPANTS

One thousand three hundred fourteen patients undergoing coronary artery surgery.

INTERVENTIONS

Off-pump coronary artery bypass grafting (OPCAB). Epiaortic ultrasound was performed in all patients.

MEASUREMENTS AND MAIN RESULTS

Complete pre-, intra- and postoperative data including the number of transfused blood products as well as the timing, type, and course of stroke were available in all patients. Postoperative stroke occurred in 23 patients (1.8%). Logistic regression identified transfusion of platelets (3.6% v 1.1%, p = 0.003, OR 3.34, 95%CI 1.46-7.67) and diseased ascending aorta (3.0% v 1.2%, p = 0.022, OR 2.64, 95% CI 1.15-6.06) as independent predictors of stroke. When these variables were adjusted for CHA2DS2VASc (p = 0.005, OR 1.44, 95% CI 1.12-1.86), only transfusion of platelets (p = 0.012, OR 2.91, 95% CI 1.26-6.70) was associated with stroke. Neither nadir hematocrit on the day of surgery nor nadir hematocrit during the perioperative period was an independent predictor of stroke. Chi-squared automatic interaction detection analysis identified solvent/detergent-treated plasma (Octaplas; Octapharma AG, Lachen, Switzerland) units >2 and platelet units >4 along with diseased ascending aorta as independent predictors of stroke. The stroke rate was 8.9% in patients receiving >2 units of Octaplas and having a diseased ascending aorta. In patients receiving ≤2 units of Octaplas, the stroke rate was as high as 3.8% in patients receiving >4 units of platelets.

CONCLUSIONS

The results of this study indicated that atherosclerosis of the ascending aorta as well as transfusion of platelets and/or Octaplas were independent predictors of stroke after OPCAB.

Novel emboli protection system during cardiac surgery: a multi-center, randomized, clinical trial

BACKGROUND

Stroke is a major cause of morbidity and mortality during open-heart surgery. Up to 60% of intraoperative cerebral events are emboli induced. This randomized, controlled, multicenter trial is the first human study evaluating the safety and efficacy of a novel aortic cannula producing simultaneous forward flow and backward suction for extracting solid and gaseous emboli from the ascending aorta and aortic arch upon their intraoperative release.

METHODS

Sixty-six patients (25 females; 68±10 years) undergoing elective aortic valve replacement surgery, with or without coronary artery bypass graft surgery, were randomized to the use of the CardioGard (CardioGard Medical, Or-Yehuda, Israel) Emboli Protection cannula ("treatment") or a standard ("control") aortic cannula. The primary endpoint was the volume of new brain lesions measured by diffusion-weighted magnetic resonance imaging (DW-MRI), performed preoperatively and postoperatively. Device safety was investigated by comparisons of complications rate, namely neurologic events, stroke, renal insufficiency and death.

RESULTS

Of 66 patients (34 in the treatment group), 51 completed the presurgery and postsurgery MRI (27 in the treatment group). The volume of new brain lesion for the treatment group was (mean±standard error of the mean) 44.00±64.00 versus 126.56±28.74 mm3 in the control group (p=0.004). Of the treatment group, 41% demonstrated new postoperative lesions versus 66% in the control group (p=0.03). The complication rate was comparable in both groups.

CONCLUSIONS

The CardioGard cannula is safe and efficient in use during open-heart surgery. Efficacy was demonstrated by the removal of a substantial amount of emboli, a significant reduction in the volume of new brain lesions, and the percentage of patients experiencing new brain lesions.

Diffusion-weighted magnetic resonance imaging lesions after repair of acute type A aortic dissection: association with neurocognitive outcomes†‡

OBJECTIVES

We sought to analyse the preoperative status of arch vessels by postoperative diffusion-weighted magnetic resonance imaging (DWI) as a potential surrogate marker for cerebral thromboembolism and its relationship to neurocognitive outcomes.

METHODS

Preoperative computed tomography (CT) and postoperative DWI were available for 50 patients who received surgery for acute type A aortic dissection. Two radiologists evaluated CT and DWI scans. Mini-mental status examinations (MMSE) were performed on the same day with DWI.

RESULTS

Mean age of participants was 57 ± 14 years. MMSE and DWI were performed 6 ± 3 days after surgery. New cerebral embolisms were evident in 35 of 50 patients (70%) and often occurred as multiple lesions (28/35, 80%; range 2-21). Among patients with multiple lesions, 23 (66%) were clinically silent. Pathological lesions at the origin of the arch vessels correlated with the number and volume of new DWI lesions (P < 0.05). Degree of neurocognitive dysfunction tested by MMSE was negatively associated with age (r = -0.48, P < 0.0001) and left-sided DWI lesion number and volume (r = -0.74, P < 0.0001; r = -0.707, P < 0.0001).

CONCLUSIONS

DWI revealed new cerebral embolisms in 70% of patients following surgery for acute type A aortic dissection. Lesion number and volume significantly correlated with pathological status of arch vessels. MMSE was representative of left-sided lesions.

Silent cerebral infarcts associated with cardiac disease and procedures

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.

Investigation of risks for cerebral embolism associated with the hemodynamics of cardiopulmonary bypass cannula: a numerical model

Cerebral emboli originating in the ascending aorta are a major cause of noncardiac complications following cardiac surgery. The hemodynamics of the aortic cannula has been proven to play a significant role in emboli generation and distribution. The aim of the current study was to perform a thorough numerical investigation in order to examine the effect of the design and orientation of the cannula used during cardiopulmonary bypass on the risk to develop cerebral embolism. Hemodynamic analyses compared numerical models of 27 cases consisting of six different cannula orientations, four aortic anatomies, and three cannula designs. The cannula designs included a straight-tip (ST) cannula, a moderately curved tip cannula (TIP1 ), and a sharp-angle curved cannula (TIP2 ). Outcome measures included hemodynamic parameters such as emanating jet velocity, jet velocity drop, maximal shear stress, aortic wall reaction, emboli pathlines and distribution between upper and lower vessels, and stagnation regions. Based on these parameters, the risks for hemolysis, atheroembolism, and cerebral embolism were evaluated and compared. On one hand, the jet emerging from the ST cannula generated large wall-shear stress at the aortic wall; this may have triggered the erosion and distribution of embolic atheromatous debris from the aortic arch. On the other hand, it diverted more emboli from the clamp region to the descending aorta and thus reduced the risk for cerebral embolism. The TIP1 cannula demonstrated less shear stress on the aortic wall and diverted more emboli from the clamp region toward the upper vessels. The TIP2 cannula exhibited a stronger emanating jet, higher shear stress inside the cannula, and highly disturbed flow, which was more stagnant near the clamp region. Current findings support the significant impact of the cannula design and orientation on emboli generation and distribution. Specifically, the straight tip cannula demonstrated a reduced risk of cerebral embolism, which may be pivotal in the clinical setting.

Novel emboli protection cannula during cardiac surgery: first animal study

Background

Stroke after open heart surgery is a major cause of morbidity and mortality. Up to 60% of intraoperative cerebral events are caused by emboli generated by manipulations of the aorta during surgery. This is the first animal study evaluating the safety and efficacy of a novel aortic cannula designed to extract solid and gaseous emboli during cardiac surgery.

Methods

Seven domestic pigs were connected to cardiopulmonary bypass using a CardioGard 24F aortic cannula. Three pigs that were cannulated with a standard aortic cannula were defined as controls. Several main flow and suction regimens were carried out. Osseous particles of different sizes were injected into the proximal aorta to simulate emboli.

Results

The CardioGard cannula demonstrated an overall emboli retrieval rate of 77%. A rate of 88.45% was demonstrated during the low-flow regimen used clinically during aortic manipulation. Gaseous and solid emboli were eliminated by suction, as demonstrated by epi-carotid ultrasound. No significant changes were observed in hemodynamic and laboratory parameters.

Conclusions

The CardioGard cannula is as simple to use as a regular commercially available aortic cannula, having a similar safety profile and proven efficacy in capturing intraoperative emboli.

Blood-brain barrier disruption after cardiac surgery

BACKGROUND AND PURPOSE

CNS complications are often seen after heart surgery, and postsurgical disruption of the BBB may play an etiologic role. The objective of this study was to determine the prevalence of MR imaging-detected BBB disruption (HARM) and DWI lesions after cardiac surgery.

MATERIALS AND METHODS

All patients had an MRI after cardiac surgery. For half the patients (group 1), we administered gadolinium 24 hours after surgery and obtained high-resolution DWI and FLAIR images 24-48 hours later. We administered gadolinium to the other half (group 2) at the time of the postoperative scan, 2-4 days after surgery. Two stroke neurologists evaluated the images.

RESULTS

Of the 19 patients we studied, none had clinical evidence of a stroke or delirium at the time of the gadolinium administration or the scan, but 9 patients (47%) had HARM (67% in group 1; 30% in group 2; P = .18) and 14 patients (74%) had DWI lesions (70% in group 1; 78% in group 2; P = 1.0). Not all patients with DWI lesions had HARM, and not all patients with HARM had DWI lesions (P = .56).

CONCLUSIONS

Almost half the patients undergoing cardiac surgery have evidence of HARM, and three-quarters have acute lesions on DWI after surgery. BBB disruption is more prevalent in the first 24 hours after surgery. These findings suggest that MR imaging can be used as an imaging biomarker to assess therapies that may protect the BBB in patients undergoing heart surgery.