Predictors of stroke risk in coronary artery bypass patients

Stroke after Cardiac Surgery: A Risk Factor Analysis of 580,117 Patients from UK National Adult Cardiac Surgical Audit Cohort

Cerebrovascular accident is the most ominous complication observed after cardiac surgery, carrying an increased risk of morbidity and mortality. Analysis of the problem shows its multidimensional nature. In this study, we aimed to identify major determinants among classic variables, either demographic, clinical or type of surgical procedure, based on the analysis of a large dataset of 580,117 patients from the UK National Adult Cardiac Surgical Audit (NACSA). For this purpose, univariate and multivariate logistic regression models were utilized to determine associations between predictors and dependent variable (Stroke after cardiac surgery). Odds ratios (ORs) and 95% confidence intervals (CIs) were constructed for each independent variable. Statistical analysis allows us to confirm with greater certainty the predictive value of some variables such as age, gender, diabetes mellitus (diabetes treated with insulin OR = 1.37, 95%CI = 1.23-1.53), and systemic arterial hypertension (OR = 1.11, 95%CI = 1.05-1.16);, to emphasize the role of preoperative atrial fibrillation (OR = 1.10, 95%CI = 1.03-1.16) extracardiac arteriopathy (OR = 1.70, 95%CI = 1.58-1.82), and previous cerebral vascular accident (OR 1.71, 95%CI = 1.6-1.9), and to reappraise others like smoking status (crude OR = 1.00, 95%CI = 0.93-1.07 for current smokers) or BMI (OR = 0.98, 95%CI = 0.97-0.98). This could allow for better preoperative risk stratification. In addition, identifying those surgical procedures (for example thoracic aortic surgery associated with a crude OR of 3.72 and 95%CI = 3.53-3.93) burdened by a high risk of neurological complications may help broaden the field of preventive and protective techniques.

Risk Factors for Stroke Development After Thoracic Aortic Surgery

OBJECTIVES

Stroke after thoracic aortic surgery is a complication that is associated with poor outcomes. The aim is to characterize the intraoperative risk factors for stroke development.

DESIGN

A retrospective analysis.

SETTING

Tertiary, high-volume cardiac surgery center.

PARTICIPANTS

Patients who had surgical repair of thoracic aortic diseases from January 1, 2017, through December 31, 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 704 patients were included, of whom 533 had ascending aortic aneurysms, and 171 had type A aortic dissection. The incidence of postoperative stroke was 4.5% (95% CI 2.9%-6.6%) for ascending aortic aneurysms compared with 12.3% (95% CI 7.8%-18.16%) in type-A aortic dissections. Patients who developed postoperative strokes had significantly lower intraoperative hemoglobin median (7.5 gm/dL [IQR 6.8-8.6] v 8.55 gm/dL [IQR 7.3-10.0]; p < 0.001). The median cardiopulmonary bypass time was 185 minutes (IQR 136-328) in the stroke group versus 156 minutes (IQR 113-206) in the nonstroke group (p = 0.014). Circulatory arrest was used in 57.8% versus 38.5% of the nonstroke patients (p = 0.017). The initial temperature after leaving the operating room was lower, with a median of 35.0°C (IQR 34-35.92) in the stroke group versus 35.5°C (IQR 35-36) in the nonstroke cohort (p = 0.021).

CONCLUSIONS

This single-center study highlighted the potential importance of intra-operative factors in preventing stroke. Lower hemoglobin, longer duration of cardiopulmonary bypass, deep hypothermic circulatory arrest, and postoperative hypothermia are potential risk factors for postoperative stroke. Further studies are needed to prevent this significant complication in patients with thoracic aortic diseases.

Cardiopulmonary bypass for total aortic arch replacement surgery: A review of three techniques

One treatment for acute type A aortic dissection is to replace the ascending aorta and aortic arch with a graft during circulatory arrest of the lower body, but this is associated with high mortality and morbidity. Maintaining the balance between oxygen supply and demand during circulatory arrest is the key to reducing morbidity and is the primary challenge during body perfusion. The aim of this review is to summarize current knowledge of body perfusion techniques and to predict future development of this field. We present three perfusion techniques based on deep hypothermic circulatory arrest (DHCA): DHCA alone, DHCA with selective cerebral perfusion, and DHCA with total body perfusion. DHCA was first developed to provide a clear surgical field, but it may contribute to stroke in 4%–15% of patients. Antegrade or retrograde cerebral perfusion can provide blood flow for the brain during circulatory arrest, and it is associated with much lower stroke incidence of 3%–9%. Antegrade cerebral perfusion may be better than retrograde perfusion during longer arrest. In theory, blood flow can be provided to all vital organs through total body perfusion, which can be implemented via either arterial or venous systems, or by combining retrograde inferior vena caval perfusion with antegrade cerebral perfusion. However, whether total body perfusion is better than other techniques require further investigation in large, multicenter studies. Current techniques for perfusion during circulatory arrest remain imperfect, and a technique that effectively perfuses the upper and lower body effectively during circulatory arrest is missing. Total body perfusion should be systematically compared against selective cerebral perfusion for improving outcomes after circulatory arrest.

The role of optimism in manifesting recovery outcomes after coronary artery bypass graft surgery: A systematic review

OBJECTIVE

Coronary artery bypass graft (CABG) is a major surgery conducted in coronary heart disease management. Postoperative recovery is a crucial process for patients undergoing CABG. This systematic review evaluates current evidence regarding the association between trait optimism and recovery outcomes in patients following coronary artery bypass graft surgery.

METHODS

This review followed the Preferred Reporting Items of Systematic Review and Meta-Analysis (PRISMA) 2020 Guideline. The inclusion criteria focused on observational study that examined study participants aged ≥18 years old undergoing elective CABG and measurement of trait optimism with validated methods (i.e. LOT, LOT-R) and at least one recovery outcome. Studies in non-English languages and duplicates were excluded. A systematic literature search was carried out on PubMed, Scopus, and Web of Science electronic databases. Search results were screened based on the eligibility criteria. The Newcastle-Ottawa Scale was used to assess the quality of each included study.

RESULTS

The search yielded a total of 1853 articles, in which 7 articles fulfilled the eligibility criteria and were subsequently included in the analysis. Measurement of trait optimism was conducted on 1276 patients who underwent a non-emergency/elective CABG. Optimism was significantly associated with several categories of recovery, including reduced rehospitalization rate, complications, pain, and physical symptoms along with improved quality of life, rate of return to normal life, and psychological status.

CONCLUSION

Our review showed that trait optimism was associated with recovery outcomes following CABG surgery. However, the heterogeneity of recovery outcomes may hamper the clinical benefit of trait optimism in CABG. (PROSPERO CRD42022301882).

Impact of postoperative complications after cardiac surgery on long-term survival

PURPOSE

The impact of postoperative complications on long-term survival is not well characterized. We sought to study the prevalence of postoperative complications after cardiac surgery and their impact on long-term survival.

METHODS

Operative survivors (n = 26,221) who underwent coronary artery bypass grafting (CABG) (n = 13,054, 49.8%), valve surgery (n = 8667, 33.1%) or combined CABG and valve surgery (n = 4500, 17.2%) from 1993 to 2019 were included in the study. Records were reviewed for postoperative complications and long-term survival. Propensity-match analysis was performed between patients who did and did not have a postoperative complication. The associations between postoperative complications and survival were assessed using a Cox-proportional model.

RESULTS

Complications occurred in 17,463 (66.6%) of 26,221 operative survivors. A total of 17 postoperative complications were analyzed. Postoperative blood product use was the commonest (n = 12,397, 47.3%), followed by atrial fibrillation (n = 8399, 32.0%), prolonged ventilation (n = 2336, 8.9%), renal failure (n = 870, 3.3%), reoperation for bleeding (n = 859, 3.3%) and pacemaker/ICD insertion (n = 795, 3.0%). Stroke (hazard ratio [HR]: 1.55; 95% confidence interval [CI]: 1.36-1.77), renal failure (HR: 1.45; 95% CI: 1.33-1.58) and pneumonia (HR: 1.23; 95% CI: 1.11-1.36) had the strongest impact on long-term survival. Long-term survival decreased as the number of postoperative complications increased.

CONCLUSIONS

Postoperative complications after cardiac surgery significantly impact outcomes that extend beyond the postoperative period. Stroke, renal failure, and pneumonia are particularly associated with poor long-term survival.

Timing of Recognition for Perioperative Strokes Following Cardiac Surgery

INTRODUCTION

More than half of reported perioperative strokes following cardiac surgery are identified beyond postoperative day one. The objective of our study was to determine preoperative and intraoperative factors that are associated with stroke following cardiac surgery and to identify factors that may contribute delayed recognition of perioperative stroke.

METHODS

Patients undergoing coronary artery bypass surgery or isolated valve surgery from January 2, 2015 to April 28, 2017 at an academic health system were identified from the Society of Thoracic Surgeons Registry. We determined preoperative and intraoperative factors associated with perioperative stroke. Two neurologists performed retrospective chart reviews on perioperative stroke patients to determine the last seen well time and the stroke cause.

RESULTS

During the study period, 2795 patients underwent coronary artery bypass surgery or isolated valve surgery (mean age 64 ± 11 years, 71% male, 72% Caucasian, 9% history of stroke), of which 43 (1.5%) had a perioperative stroke; 31 (72%) patients had an embolic mechanism of stroke based on neuroimaging. In multivariable analysis, perioperative strokes were independently associated with increasing age (OR 1.04, 95% 1.01-1.07), history of stroke (OR 2.73, 95% CI 1.47-5.06), and history of thoracic aorta disease (OR 3.36, 95% CI 1.16-9.71). Strokes were identified after postoperative day one in 32 (74%) patients of which 26 (81%) had a preoperative last seen well time.

CONCLUSION

Given the high frequency of preoperative last seen well time in perioperative stroke patients who are identified after postoperative day one, delayed stroke recognition may contribute to the bimodal distribution in timing of perioperative stroke. Frequent neurological monitoring within 24 hours after CABG or isolated valve surgery should be considered for all patients undergoing cardiac surgery, particularly elderly patients and those with a history of stroke or thoracic aorta disease, to improve early stroke recognition.

Repair of Acute Type-A Aortic Dissection in the Present Era: Outcomes and Controversies

Acute Type-A aortic dissection (AAAD) remains a surgical emergency with a relatively high operative mortality despite advances in medical and surgical management over the past three decades. In spite of the severity of disease, there is a paucity of studies reviewing key controversies surrounding AAAD repair and management. A systematic literature search was performed using Cochrane review and PubMed bibliography review. Abstracts were first reviewed for general pertinence and then articles were reviewed in full. Literature review indicates that use of moderate hypothermia and antegrade cerebral perfusion is a safe alternative to deep hypothermia. In hemodynamically stable patients, axillary cannulation may be substituted for femoral cannulation. With regard to the technical aspects of repair, preserving the aortic root whenever possible and performing the distal anastomosis with the open distal technique rather than with the clamp on is the preferred approach. In patients with a patent false lumen, close monitoring is indicated. As demonstrated by the literature, significant improvement of early and late mortality over the past years has occurred in patients presenting with AAAD. Repair of acute Type-A aortic dissection remains a challenge with high operative mortality; however, improvement of surgical techniques and management have resulted in improvement of early and late clinical outcomes.

A Multilevel Analysis of Surgical Category and Individual Patient-Level Risk Factors for Postoperative Stroke

Background and Purpose

Many studies supporting the association between specific surgical procedure categories and postoperative stroke (POS) do not account for differences in patient-level characteristics between and within surgical categories. The risk of POS after high-risk procedure categories remains unknown after adjusting for such differences in patient-level characteristics.

Methods

Using inpatients in the American College of Surgeons National Surgical Quality Initiative Program database, we conducted a retrospective cohort study between January 1, 2000, and December 31, 2010. Our primary outcome was POS within 30 days of surgery. We characterized the relationship between surgical- and individual patient-level factors and POS by using multivariable, multilevel logistic regression that accounted for clustering of patient-level factors with surgical categories.

Results

We identified 729 886 patients, 2703 (0.3%) of whom developed POS. Dependent functional status (odds ratio [OR]: 4.11, 95% confidence interval [95% CI]: 3.60-4.69), history of stroke (OR: 2.35, 95%CI: 2.06-2.69) or transient ischemic attack (OR: 2.49 95%CI: 2.19-2.83), active smoking (OR: 1.20, 95%CI: 1.08-1.32), hypertension (OR: 2.11, 95%CI: 2.19-2.82), chronic obstructive pulmonary disease (OR: 1.39 95%CI: 1.21-1.59), and acute renal failure (OR: 2.35, 95%CI: 1.85-2.99) were significantly associated with POS. After adjusting for clustering, patients who underwent cardiac (OR: 11.25, 95%CI: 8.52-14.87), vascular (OR: 4.75, 95%CI: 3.88-5.82), neurological (OR: 4.60, 95%CI: 3.48-6.08), and general surgery (OR: 1.40, 95%CI: 1.15-1.70) had significantly greater odds of POS compared to patients undergoing other types of surgical procedures.

Conclusions

Vascular, cardiac, and neurological surgery remained strongly associated with POS in an analysis accounting for the association between patient-level factors and surgical categories.

Association of Timing of Aortic Valve Replacement Surgery After Stroke With Risk of Recurrent Stroke and Mortality

Importance

Timing of surgical aortic valve replacement (SAVR) in patients with aortic valve stenosis and previous stroke for the risk of recurrent stroke is insufficiently investigated.

Objective

To evaluate the association of time elapsed between previous stroke and SAVR with the risk of recurrent perioperative stroke, major adverse cardiovascular events (MACE), and mortality among patients with aortic valve stenosis.

Design, Setting, and Participants

This cohort study using data from Danish administrative registries included all patients with aortic valve stenosis older than 18 years who underwent SAVR between 1996 and 2014 (n = 14 030). Patients who received simultaneous mitral, tricuspid, or pulmonary valve surgery and patients with endocarditis 1 year prior to surgery were excluded. Data were analyzed from March 2017 to January 2018.

Exposures

Time elapsed between prior stroke and SAVR (<3 months, 3-<12 months, ≥12 months, and no prior stroke).

Main Outcomes and Measures

Thirty-day risks of MACE, ischemic stroke, and all-cause mortality reported as absolute events and multivariable adjusted odds ratios with 95% confidence intervals. Restricted cubic spline regression models were additionally applied on the subgroup with prior stroke.

Results

Of the 14 030 included patients, 616 patients (190 [30.8%] women; mean [SD] age, 72.0 [9.1] years) with prior stroke underwent surgery, and 13 414 (4837 [36.1%] women; mean [SD] age, 69.8 [10.8] years) without prior stroke underwent surgery. The absolute risk of ischemic stroke was significantly increased in patients with stroke less than 3 months prior to surgery compared with patients with no prior stroke (18.4% [37 of 201] vs 1.2% [160 of 13 219]; odds ratio, 14.69; 95% CI, 9.69-22.27). Likewise, compared with patients without stroke, patients with stroke less than 3 months prior surgery were at significantly increased risk of MACE (23.3% [53 of 227] vs 5.7% [768 of 13 414]; odds ratio, 4.57; 95% CI, 3.24-6.44) but not all-cause mortality (6.8% [50 of 730] vs 3.6% [374 of 10 370]; odds ratio, 1.45; 95% CI, 0.83-2.54). Spline analyses supported a declining risk over time, reaching nadir after 2 to 4 months.

Conclusions and Relevance

Previous stroke is a major risk factor of recurrent ischemic stroke and MACE in patients undergoing SAVR, especially if time elapsed between previous stroke and surgery is less than 3 months.

A functional evaluation of cerebral perfusion for coronary artery bypass grafting patients

We evaluate the utility of providing a pulsatile blood flow by applying off-pump coronary artery bypass grafting (CABG) or intra-aortic balloon pumping (IABP) with conventional CABG to prevent perioperative stroke in patients with cerebral hypoperfusion on single-photon emission-computed tomography (SPECT). A total of 286 patients underwent isolated CABG with a cerebral magnetic resonance angiography (MRA) evaluation between 2006 and 2015. Seventy-five had significant stenosis and/or occlusion of craniocervical vessels; the other 211 had no significant stenosis. Cerebral SPECT was performed for 49 (SPECT group) of the 75 patients. The SPECT group was further divided into a normal perfusion (NP) (n = 37); and a hypoperfusion (HP) (n = 12). In the present study we compared the NP group and the 211 patients with no significant stenosis (as a control group) to the HP group. No strokes occurred in the HP group, and 1 stroke occurred at the time of operation in the control group. Postoperative stroke within 30 days occurred in 3 patients in the control group; the difference was not statistically significant. The long-term stroke-free rates of the HP and Control group did not differ to a statistically significant extent. The functional evaluation of cerebral perfusion by SPECT is important when patients have significant stenotic lesions on cerebral MRA. Maintaining an adequate pulsatile flow by off-pump CABG or IABP with conventional CABG will help prevent perioperative stroke, even if cerebral hypoperfusion is detected by SPECT.

Role of Moderate Hypothermia and Antegrade Cerebral Perfusion during Repair of Type A Aortic Dissection

The goal of this study was to compare early postoperative outcomes and actuarial survival between patients who underwent repair of acute type A aortic dissection with deep or moderate hypothermia. A total of 132 consecutive patients from a single academic medical center underwent repair of acute type A aortic dissection between January 2000 and June 2014. Of those, 105 patients were repaired under deep hypothermia (< 24 C°), while 27 patients were repaired under moderate hypothermia (≥24 C°). Median ages were 62 years (range: 27-86) and 59 years (range: 35-83) for patients repaired under deep hypothermia compared with patients repaired under moderate hypothermia, respectively ( p  = 0.451). Major morbidity, operative mortality, and 10-year actuarial survival were compared between groups. Operative mortality was 17.1 and 7.4% in the deep and moderate hypothermia groups, respectively ( p  = 0.208). Incidence of permanent stroke was 12.4% in the deep hypothermic circulatory arrest group and 0% in the moderate hypothermia group ( p  = 0.054). Actuarial 5- and 10-year survival demonstrated a trend for lower long-term mortality with moderate hypothermia compared with deep hypothermia (69% 5-year and 54% 10-year for deep hypothermia vs. 79% 5-year and 10-year for moderate hypothermia, log-rank p  = 0.161). Moderate hypothermia is a safe and efficient alternative to deep hypothermia and may have protective benefits. Stroke rate was lower with moderate hypothermia.

Computer-Simulated Fluid Dynamics of Arterial Perfusion in Extracorporeal Circulation: From Reality to Virtual Simulation

Background

Atheroembolism due to aortic manipulation remains an unsolved problem in surgery for thoracic aortic aneurysm. The goal of the present study is to create a computer simulation (CS) model with which to analyze blood flow in the diseased aorta.

Method

A three-dimensional glass model of the aortic arch was constructed from CT images of a normal, healthy person and a patient with transverse aortic arch aneurysm. Separately, a CS model of the curved end-hole cannula was created, and flow from the aortic cannula was recreated using a numerical simulation.

Results

Comparison of the data obtained by the glass model analyses revealed that the flow velocity and the vector of the flow around the exit of the cannula were similar to that in the CS model. A high-velocity area was observed around the cannula exit in both the glass model and the CS model. The maximum flow velocity was as large as 1.0 m/s at 20 mm from the cannula exit and remained as large as 0.5 to 0.6 m/s within 50 mm of the exit. In the aortic arch aneurysm models, the rapid jet flow from the cannula moved straight toward the lesser curvature of the transverse aortic arch. The locations and intensities of the calculated vortices were slightly different from those obtained for the glass model.

Conclusions

The proposed CS method for the analysis of blood flow from the aortic cannulae during extracorporeal circulation can reproduce the flow velocity and flow pattern in the proximal and transverse aortic arches.

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.

Internal Carotid Artery Occlusion: Association With Atherosclerotic Disease in Other Arterial Beds and Vascular Risk Factors

The aim of this article is to investigate the association between internal carotid artery occlusion (ICAO) and the presence of atherosclerotic disease and vascular risk factors. The clinical characteristics and risk factors of 120 patients presenting with ICAO were retrospectively reviewed. All patients (n = 120) had at least 1 of the 4 vascular risk factor (diabetes, smoking, hypercholesterolemia, and hypertension); 2, 3, or all 4 risk factors were present in 14 to 82 of the patients (11.7% to 68.3%), 10 to 39 of the patients (8.3% to 32.5%), and 9 of the patients (7.5%), respectively. A total of 84 patients (70%) with ICAO had disease in at least 1 additional vascular bed (aorta, coronary or lower limb arteries). In addition to ICAO, vascular disease was present in 2 and all 3 of these arterial beds in 42 (35%) and 9 (7.5%) patients, respectively. Furthermore, stenosis or occlusion of the ipsilateral or contralateral vertebral arteries was recorded in 19 of 120 patients (15.8%). Regarding the contralateral carotid artery, 1 patient had bilateral ICAO. One patient had contralateral common carotid artery occlusion, and 1 patient was excluded from the analysis because of surgery to the contralateral carotid artery. Of the remaining 117 patients, 34 (29.0%) had less than 50% contralateral carotid artery stenosis. Thirty-two patients (27.4%) had 50% to 69%, and 51 (43.6%) had 70% to 99% stenosis. Ultrasonographic imaging of the carotid plaque of the contralateral carotid artery revealed that 52 of the 120 arteries (43.3%) were uniformly or predominantly echolucent (types I and II, respectively). Fifty-nine (49.2%) were predominantly or uniformly echogenic (types III and IV), and 9 (7.5%) could not be classified. A similar distribution of echomorphology was observed on the occluded side. ICAO is associated with widespread atherosclerotic disease and a high prevalence of vascular risk factors. Detection of ICAO should prompt the investigation of other arterial beds and treatment of risk factors.

The Impact of Intraoperative Echocardiography on Clinical Outcomes Following Adult Cardiac Surgery

Over the past 30 years, intraoperative echocardiography has become an invaluable diagnostic tool and monitor of cardiac performance for the management of cardiac surgical patients. The essential information provided by intraoperative echocardiography regarding hemodynamic management, cardiac valve function, congenital heart lesions, and great vessel pathology has contributed to its widespread popularity. Numerous investigations have been conducted in an attempt to specifically demonstrate a beneficial impact of intraoperative echocardiography in cardiac surgery. However, there is a relative paucity of data derived from prospective trials in which the use of intraoperative echocardiography has been randomized among various cardiac surgical patient populations to formally ascertain, rather than simply infer, its putative impact on perioperative decision-making and clinical outcomes. Ironically, the popularity of intraoperative echocardiography has imposed ethical limitations on performing randomized trials in patient populations for whom significant benefit has been previously inferred. Nonetheless, significant evidence has been published to support its almost universal acceptance as an important perioperative diagnostic tool and monitor for cardiac surgical patients. This review focuses on the impact of intraoperative echocardiography on clinical outcomes in the more common adult cardiac surgical scenarios, including coronary artery bypass graft surgery, mitral and aortic valve surgery, and in evaluating the intrathoracic aorta.

Neurologic aspects of cardiac emergencies

In this review, cardiac arrest is discussed, with a focus on neuroprognostication and the emerging data, with regard to identifying more accurate predictors of neurologic outcomes in the era of therapeutic hypothermia. Topics discussed include recent controversies with regard to targeted temperature management in comatose survivors of cardiac arrest; neurologic complications associated with surgical disease and procedures, namely aortic dissection, infective endocarditis, left ventricular assist devices, and coronary artery bypass grafting; and the cause, pathogenesis, and management of neurogenic stunned myocardium.

A network of pulmonary vein thrombi is a risk factor for ischemic stroke, especially after cardiac surgery: A case report and mini review

Stroke remains a devastating complication following cardiac surgery. Pulmonary vein thrombi (PVT) are believed to be rare, but I have reported 37 cases of PVT in elderly patients with chest pain since 2012, indicating that PVT are not unusual. The present case showed that PVT can make a network among four pulmonary veins and left atrium. Currently, PVT are not recognized as a risk factor for ischemic stroke, especially following cardiac surgery.

A 76-year-old male was examined by 64-slice multidetector CT (64-MDCT) to assess chest pain. The 64-MDCT scan revealed thrombi in the left upper and lower pulmonary veins, the right upper and lower pulmonary veins and the left atrium (LA) as the defects of contrast enhancements. The LA thrombi seemed to be connected to PVT forming a network of thrombi.

To avoid stroke following cardiac surgery, it is important to cope with PVT. How to treat PVT during cardiac surgery should be developed.

Stroke after coronary artery surgery: a single center report

Stroke or cerebrovascular accident (CVA) is a devastating complication of coronary surgery. In this report, the incidence, and correlates of CVA following isolated coronary artery bypass grafting (CABG) surgery were evaluated. Data were collected retrospectively. Between 2006 and 2009, 855 patients underwent isolated CABG surgery. CVA was defined as any new neurological deficit lasting more than 24 hours. Univariate and multivariate analyses were utilized as appropriate. The incidence of CVA was 1.4% (n = 12). Age, previous CVA, and emergency surgery were correlated by univariate analysis. Multivariate analysis revealed age, previous CVA, and chronic renal impairment as predictors of CVA. Ten (83.3%) of the 12 patients were diagnosed to have CVA in the first 24 hours. Length of hospital stay was 20.9 ± 20.34 days for CVA patients and 9.2 ± 5.17 days for non-CVA patients (p ≤ 0.001). There were 4 (33.3%) deaths in CVA group and 27 (3.2%) for non-CVA patients (p = 0.001). Postoperative CVA is a major contributor to mortality, prolonged hospitalization, and other adverse postoperative complications. Further studies are needed to develop better strategies to minimize the occurrence of CVA among patients undergoing CABG.

Outcomes and predictors of mortality and stroke after on-pump and off-pump coronary artery bypass surgery in octogenarians

OBJECTIVE

Octogenarians, as the fastest growing stratum of the population and with the highest prevalence of coronary artery disease, are being increasingly referred for coronary artery bypass grafting (CABG). The general perception is that the presence of comorbidities and the propensity for neurological injury expose them to a higher risk for mortality and morbidity after conventional on-pump CABG, and therefore, off-pump CABG should be preferentially offered to octogenarians to improve outcomes. This study evaluates the in-hospital outcomes and predictors of mortality and stroke in octogenarians undergoing on- and off-pump CABG at our institution.

METHODS

From January 2000 to December 2010, a total of 290 octogenarians underwent off-pump (n = 217) and on-pump (n = 73) CABG. Their data were prospectively entered into the cardiac surgery database (Patients Analysis & Tracking System; Dendrite Clinical Systems, Ltd, Oxford, England, United Kingdom) and analyzed retrospectively. Outcome measures included in-hospital mortality, major complications, and length of stay. Multivariate analysis was performed to identify predictors of combined outcome of in-hospital mortality and stroke.

RESULTS

The mean ± SD age of the patients was 82 ± 2.0 years. Preoperative demographics were similar for the on-pump and off-pump groups. The patients who underwent off-pump CABG had a lower number of distal anastomoses performed compared with the patients who underwent on-pump CABG [mean difference, 0.2; 95% confidence interval (CI), 0.02-0.4; P = 0.03]. However, the ratio of grafts (received/needed) was the same in both groups. In-hospital mortality for the entire cohort was 7.2%, with no significant difference between the groups for death (6.0% vs 11.0%; P = 0.08), stroke (2.8% vs 2.8%; P = 1.0), other major complications, and length of hospital stay. Independent predictors of combined outcome identified from the multiple logistic model included heart failure [odds ratio (OR), 4.4; 95% CI, 1.5-13.0; P = 0.008], diabetes (OR, 2.6; 95% CI, 1.0-6.0; P = 0.046), nitrate infusion (OR, 2.9; 95% CI, 1.1-8.0; P = 0.04), postoperative renal failure requiring hemofiltration (OR, 8.6; 95% CI, 3.5-21.1; P < 0.001), and postoperative ventricular arrhythmias (OR, 7.3; 95% CI, 1.9-27.8; P = 0.009).

CONCLUSIONS

Both on-pump and off-pump CABG are reasonable revascularization strategies in octogenarians. Careful patient selection and individualized treatment decisions can minimize postoperative mortality and morbidity in octogenarians undergoing on- and off-pump CABG.

Coronary artery bypass graft surgery: the past, present, and future of myocardial revascularisation

The development of the heart-lung machine ushered in the era of modern cardiac surgery. Coronary artery bypass graft surgery (CABG) remains the most common operation performed by cardiac surgeons today. From its infancy in the 1950s till today, CABG has undergone many developments both technically and clinically. Improvements in intraoperative technique and perioperative care have led to CABG being offered to a more broad patient profile with less complications and adverse events. Our review outlines the rich history and promising future of myocardial revascularization.

Myocardial revascularization for the elderly: current options, role of off-pump coronary artery bypass grafting and outcomes

The increase in life expectancy has confronted cardiac surgery with a rapidly growing population of elderly patients requiring surgical myocardial revascularization. Recent advances in surgical and anesthetic techniques and improvements in postoperative care have made coronary artery bypass grafting an established therapeutic option for the treatment of coronary artery disease in this group of patients. However, conventional coronary artery bypass grafting on cardiopulmonary bypass is associated with significant risk and related morbidity and mortality in the elderly. In recent years off-pump coronary artery bypass grafting has emerged as a safe and less invasive strategy for surgical myocardial revascularization. Off-pump coronary artery bypass grafting by avoiding the deleterious effects of cardiopulmonary bypass can offer potential benefits to elderly patients requiring surgical myocardial revascularization. This review article provides an overview of the age-related cardiovascular changes, epidemiology of coronary artery disease in the elderly and focuses on outcomes of surgical myocardial revascularization with special emphasis on the impact of off-pump coro-nary artery bypass surgery in the elderly.

Trends in aortic clamp use during coronary artery bypass surgery: effect of aortic clamping strategies on neurologic outcomes

OBJECTIVE

The purpose of the present study was to determine the effect of different clamping strategies during coronary artery bypass grafting on the incidence of postoperative stroke.

METHODS

In the present case-control study, all patients at Emory hospitals from 2002 to 2009 with postoperative stroke after isolated coronary artery bypass grafting (n = 141) were matched 1:4 to a contemporaneous cohort of patients without postoperative stroke (n = 565). The patients were matched according to the Society of Thoracic Surgeons' predicted risk of postoperative stroke score, which is based on 26 variables. The patients who received on-pump and off-pump coronary artery bypass grafting were matched separately. Multiple logistic regression analysis with adjusted odds ratios was performed to identify the operative variables associated with postoperative stroke.

RESULTS

Among the on-pump cohort, the single crossclamp technique was associated with a decreased risk of stroke compared with the double clamp (crossclamp plus partial clamp) technique (odds ratio, 0.385; P = .044). Within the on-pump cohort, no significant difference was seen in the incidence of stroke according to clamp use. Epiaortic ultrasound of the ascending aorta increased from 45.3% in 2002 to 89.4% in 2009. From 2002 to 2009, clamp use decreased from 97.7% of cases to 72.7%.

CONCLUSIONS

During on-pump coronary artery bypass grafting, the use of a single crossclamp compared with the double clamp technique decreased the risk of postoperative stroke. The use of any aortic clamp decreased and epiaortic ultrasound use increased from 2002 to 2009, indicating a change in the operative technique and surgeon awareness of the potential complications associated with manipulation of the aorta.

Pre- and perioperative risk factors predicting neurologic outcomes after coronary artery bypass surgery in patients with pre-existing neurologic events

BACKGROUND

A neurologic event (NE) after coronary artery bypass graft (CABG) surgery is a principal complication affecting morbidity and mortality. We investigated the risk factors predicting postoperative NEs and survival in patients with pre-existing NE undergoing CABG.

METHODS

Between 2001 and 2012, 3137 patients underwent isolated primary CABG. The data were stored in a computerized database and retrospectively evaluated. Patients were divided into 2 groups based on the existence of preoperative NE (study group; n=126) and without NE (n=3011). Uni- and multivariate logistic regression analyses were performed to evaluate the possible predictors of postoperative NEs. Survival was determined using Kaplan-Meier survival analyses of the study group and propensity score-matched control group.

RESULTS

The mean age of the 3137 patients was 60±9 years, and 28% (n=885) were female. Postoperative NE was seen in 4 (3.2%) patients with pre-existing NE and in 16 (0.5%) without pre-existing NE. Preoperative NE (odds ratio 4.47; 95% confidence interval 1.32-15.18; P=.01) and age (≥70 years; odds ratio 2.98; 95% confidence interval 1.21-7.33; P=.01) showed strong multivariate associations with postoperative NE. Median CHA2DS2-VASc scores were 4.5 (interquartile range 3-5) and 3 (range 0-4) in patients in the pre-existing and without NE groups, respectively (P=.01). The overall mean follow-up was 4.6±3 years. Overall survival rates (88.1% and 94%, respectively) were different between the 2 groups (P=.02).

CONCLUSIONS

Preoperative neurologic events and advanced age are significant risk factors predicting postoperative neurologic events. Meticulous management of the ascending aorta and carotid artery are important in diminishing postoperative neurologic events. A pre-existing neurologic event is also predictive for decreased overall survival.

[Acute neurological complications after pediatric cardiac surgery: still a long way to go]

INTRODUCTION

There has been an increasing concern over the neurological complications associated with congenital heart disease and cardiac surgery.

MATERIAL AND METHODS

We performed a retrospective, case-control, observational review of the postoperative period in the intensive care unit of patients undergoing cardiac surgery over the past 10 years. We selected 2 control patients for each case, matched for surgical complexity.

RESULTS

A total of 900 patients were reviewed. We found 38 neurological complications (4.2%), of which 21 (55.3%) were in the peripheral nervous system and 17 (44.7%) in the central nervous system. The complications involving the central nervous system (1.9% of total) consisted of 8 seizures, 4 cerebrovascular accidents, 4 hypoxic-ischemic encephalopathy events, and 1 reversible neurological deficit. At the time of discharge, 35.3% were symptomatic and 17.6% had died. Patients with neurological complications had a longer bypass time (P=.009), longer aortic cross time (P=.012), longer hospitalization in intensive care (P=.001), longer duration of mechanical ventilation (P=.004) and an increased number of days under inotropic support (P=.001).

CONCLUSIONS

Our incidence of neurological complications after cardiac surgery is similar to that previously described. Clinical seizures are the most common complication. Central nervous system complications are associated with a higher morbidity and hospitalization time. Units caring for patients with congenital heart disease must implement neurological monitoring during and after cardiac surgery to prevent and to detect these complications earlier.

Continuous insulin infusion is associated with a reduced post-surgical length of stay, but not with the complication rate, in patients with diabetes mellitus undergoing coronary artery bypass graft

OBJECTIVE

To establish if glucose management with continuous intravenous insulin infusion (CII) in the early post-operative period after coronary artery bypass graft (CABG) surgery is associated with complication rate and length of hospital stay (LOS) in patients with diabetes mellitus (DM).

RESEARCH DESIGN AND METHODS

We reviewed the records of 587 patients with DM who underwent CABG from January 1999 until January 2008; 316 patients were placed on CII, while 271 patients were treated with subcutaneous insulin. We examined patient age, glycated hemoglobin (HgbA1c), 24- and 72-h post-operative average capillary blood glucose (CBG), length of stay (LOS), and the rate of complications.

RESULTS

There was no difference in HgbA1c between the groups. Mean CBG values at both 24 h and 72 h remained the same in the CII group (167 mg/dl), while in the non-CII group they were 194 mg/dl and 189 mg/dl, respectively (p<0.001 between the groups). Post-surgical median LOS was 6 days in the CII group and 6.5 days in the non-CII group (p=0.003). Complications occurred at similar rate (in 10% and 11% of patients) in the two groups.

CONCLUSIONS

CII is associated with a reduced post-surgical LOS in patients with DM who undergo CABG.

Antithrombotic medication for cardioembolic stroke prevention

Embolism of cardiac origin accounts for about 20% of ischemic strokes. Nonvalvular atrial fibrillation is the most frequent cause of cardioembolic stroke. Approximately 1% of population is affected by atrial fibrillation, and its prevalence is growing with ageing in the modern world. Strokes due to cardioembolism are in general severe and prone to early recurrence and have a higher long-term risk of recurrence and mortality. Despite its enormous preventive potential, continuous oral anticoagulation is prescribed for less than half of patients with atrial fibrillation who have risk factors for cardioembolism and no contraindications for anticoagulation. Available evidence does not support routine immediate anticoagulation of acute cardioembolic stroke. Anticoagulation therapy's associated risk of hemorrhage and monitoring requirements have encouraged the investigation of alternative therapies for individuals with atrial fibrillation. New anticoagulants being tested for prevention of stroke are low-molecular-weight heparins (LMWH), unfractionated heparin, factor Xa inhibitors, or direct thrombin inhibitors like dabigatran etexilate and rivaroxaban. The later exhibit stable pharmacokinetics obviating the need for coagulation monitoring or dose titration, and they lack clinically significant food or drug interaction. Moreover, they offer another potential that includes fixed dosing, oral administration, and rapid onset of action. There are several concerns regarding potential harm, including an increased risk for hepatotoxicity, clinically significant bleeding, and acute coronary events. Therefore, additional trials and postmarketing surveillance will be needed.

Impact of preexisting cerebral ischemia detected by magnetic resonance imaging and angiography on late outcome after coronary artery bypass surgery

BACKGROUND

The aim of this study was to assess the impact of preexisting ischemia detected by brain magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) on long-term survival, and cardiac and neurologic events after coronary artery bypass grafting (CABG).

METHODS

Of 923 patients who underwent CABG between 1994 and 2007, 887 patients (96.1%) were followed up. Preoperative brain MRI and MRA were performed in 619 patients. Ischemia was detected by brain MRI and MRA in 158 patients (group A), but not in 461 patients (group B). Preoperative characteristics, follow-up survival, and cardiac and neurological events were investigated.

RESULTS

The average follow-up period was 6.0 ± 4.3 years. Univariate analysis showed that patients in group A (68.5 ± 6.5 years) were older than those in group B (64.5 ± 8.6 years) (p = 0.0001). Preoperative left ventricular ejection fraction was less in group A (0.516 ± 0.175) than in group B (0.556 ± 0.165) (p = 0.02). The prevalence of peripheral vascular disease was higher in group A (14 patients: 8.9%) than in group B (11 patients: 2.4%) (p = 0.001). The rate of on-pump CABG was lower in group A (115 patients; 72.8%) than in group B (383 patients; 83.1%) (p = 0.007). Survival rate was significantly lower (p = 0.062), and freedom from major adverse cardiac event or stroke were significantly lower in group A (p = 0.0002, and p = 0.0001, respectively; log-rank test). However, the Cox proportional hazard model showed that preoperative brain ischemia detected by brain MRI and MRA affected only freedom from neurologic events (p = 0.02; hazard ratio 2.52; 95% confidence interval 1.13 to 5.62), but not survival (p = 0.67) or major adverse cardiac event (p = 0.09).

CONCLUSIONS

Preexisting ischemic findings on brain MRI and MRA in patients who underwent CABG were related only to long-term freedom from stroke, but were not related to survival or major adverse cardiac event.

Assessment of carotid artery stenosis before coronary artery bypass surgery. Is it always necessary?

BACKGROUND

Extracranial internal carotid artery stenosis is a risk factor for perioperative stroke in patients undergoing coronary artery bypass surgery (CAB). Although selective and non-selective methods of preoperative carotid screening have been advocated, it remains unclear if this screening is clinically relevant.

AIM

To test whether selective carotid screening is as effective as non-selective screening in detecting significant carotid disease.

METHODS

The case records of patients consecutively undergoing CAB were reviewed. Patients were stratified retrospectively into high- or low-risk groups according to risk factors for significant carotid stenosis and perioperative stroke: peripheral vascular disease (PVD), carotid bruit, diabetes mellitus, age >70 years and/or history of cerebrovascular disease. Prevalence of carotid stenosis detected by ultrasonography, surgical management and perioperative stroke rates were determined in each group.

RESULTS

Overall, 205 consecutive patients underwent preoperative carotid screening. The prevalence of significant carotid stenosis was 5.8%. Univariate analysis confirmed that PVD (P=0.005), carotid bruit (P=0.003) and diabetes mellitus (P=0.05) were significant risk factors for stenosis. Carotid stenosis was a risk factor for stroke (P=0.03). Prevalence of carotid stenosis was higher in the high-risk group (9.1%) than the low-risk group (1.2%) (P<0.05). All concomitant or staged carotid endarterectomies/CAB (5/205) and all patients who had perioperative strokes (5/205) were in the high-risk group (P=0.01).

CONCLUSION

In our cohort, selective screening of patients aged >70 years, with carotid bruit, a history of cerebrovascular disease, diabetes mellitus or PVD would have reduced the screening load by 40%, with trivial impact on surgical management or neurological outcomes.

Association between hypotension, low ejection fraction and cognitive performance in cardiac patients

BACKGROUND AND PURPOSE

Impaired cardiac function can adversely affect the brain via decreased perfusion. The purpose of this study was to determine if cardiac ejection fraction (EF) is associated with cognitive performance, and whether this is modified by low blood pressure.

METHODS

Neuropsychological testing evaluating multiple cognitive domains, measurement of mean arterial pressure (MAP), and measurement of EF were performed in 234 individuals with coronary artery disease. The association between level of EF and performance within each cognitive domain was explored, as was the interaction between low MAP and EF.

RESULTS

Adjusted global cognitive performance, as well as performance in visuoconstruction and motor speed, was significantly directly associated with cardiac EF. This relationship was not entirely linear, with a steeper association between EF and cognition at lower levels of EF than at higher levels. Patients with low EF and low MAP at the time of testing had worse cognitive performance than either of these alone, particularly for the global and motor speed cognitive scores.

CONCLUSIONS

Low EF may be associated with worse cognitive performance, particularly among individuals with low MAP and for cognitive domains typically associated with vascular cognitive impairment. Further care should be paid to hypotension in the setting of heart failure, as this may exacerbate cerebral hypoperfusion.

Is There a Future for Neuroprotective Agents in Cardiac Surgery?

This article gives an overview of neuroprotective drugs that were recently tested in clinical trials in cardiac surgery. Also, recommendations are given for successful translational research and considerations for management during cardiac surgery.

Serum markers of cerebral ischemia

Rapid diagnosis and management of stroke patients is becoming increasingly important with the emergence of new interventional strategies for acute cerebral ischemia. A biochemical surrogate of cerebral ischemia, rapidly detectable in the serum before radiological diagnosis, might have clinical utility in the setting of acute stroke, high-risk cardiovascular procedures, and subarachnoid hemorrhage. Such a marker might also aid in the neurological prognosis of anoxic brain injury. Several serum markers have been evaluated in acute cerebral ischemia. These include neuronal enzymes such as neuron-specific enolase; markers of glial injury and activation, such as protein S100beta; and mediators of inflammation, such as interleukin-6. The clinical and preclinical data supporting the use of these biochemical surrogates of cerebral ischemia are reviewed.

Hydrodynamics of aortic cannulae during extracorporeal circulation in a mock aortic arch aneurysm model

This study was designed to analyze flow pattern, velocity, and strain on the aortic wall of a glass aortic arch aneurysm model during the extracorporeal circulation, and to elucidate the characteristics of flow pattern in three different aortic cannulae. Different patterns of large vortices and helical flow were made by each cannula. With the curved end-hole cannula, the high velocity flow (approximately 0.6-0.8 m/s) was blowing to the aneurismal wall without attenuating the strain rate tensor (approximately 0.2-0.25/s). With the dispersion cannula and the Soft-Flow cannula, cannular jet was attenuated in the ascending aorta creating a large vortex at a velocity less than 0.5 m/s, and the strain rate tensor on the aneurismal wall was small (less than 0.15/s). In conclusion, end-hole cannula should not be used in the operation of aortic arch aneurysm. Dispersion-type aortic cannulae were less invasive on the aortic arch aneurismal wall, but particular attention to alternative cannulation sites should be paid in cases with severe atherosclerosis on the ascending aortic wall.