Stroke in coronary artery bypass graft surgery: an analysis of the CASS experience. The participants in the Coronary Artery Surgery Study

Comparison of Early Outcomes with Three Approaches for Combined Coronary Revascularization and Carotid Endarterectomy

Objective

This study aims to compare three different surgical approaches for combined coronary and carotid artery stenosis as a single stage procedure and to assess effect of operative strategy on mortality and neurological complications.

Methods

This retrospective study involves 136 patients who had synchronous coronary artery revascularization and carotid endarterectomy in our institution, between January 2002 and December 2012. Patients were divided into 3 groups according to the surgical technique used. Group I included 70 patients who had carotid endarterectomy, followed by coronary revascularization with on-pump technique, group II included 29 patients who had carotid endarterectomy, followed by coronary revascularization with off-pump technique, group III included 37 patients who had coronary revascularization with on-pump technique followed by carotid endarterectomy under aortic cross-clamp and systemic hypothermia (22-27ºC). Postoperative outcomes were evaluated.

Results

Overall early mortality and stroke rate was 5.1% for both. There were 3 (4.3%) deaths in group I, 2 (6.9%) deaths in group II and 2 (5.4%) deaths in group III. Stroke was observed in 5 (7.1%) patients in group I and 2 (6.9%) in group II. Stroke was not observed in group III. No statistically significant difference was observed for mortality and stroke rates among the groups.

Conclusion

We identified no significant difference in mortality or neurologic complications among three approaches for synchronous surgery for coronary and carotid disease. Therefore it is impossible to conclude that a single principle might be adapted into standard practice. Patient specific risk factors and clinical conditions might be important in determining the surgical tecnnique.

Orthopedic Surgery and Post-Operative Cognitive Decline in Idiopathic Parkinson's Disease: Considerations from a Pilot Study

BACKGROUND

Post-operative cognitive dysfunction (POCD) demarks cognitive decline after major surgery but has been studied to date in "healthy" adults. Although individuals with neurodegenerative disorders such as Parkinson's disease (PD) commonly undergo elective surgery, these individuals have yet to be prospectively followed despite hypotheses of increased POCD risk.

OBJECTIVE

To conduct a pilot study examining cognitive change pre-post elective orthopedic surgery for PD relative to surgery and non-surgery peers.

METHODS

A prospective one-year longitudinal design. No-dementia idiopathic PD individuals were actively recruited along with non-PD "healthy" controls (HC) undergoing knee replacement surgery. Non-surgical PD and HC controls were also recruited. Attention/processing speed, inhibitory function, memory recall, animal (semantic) fluency, and motor speed were assessed at baseline (pre-surgery), 3 weeks, 3 months, and 1 year post- orthopedic surgery. Reliable change methods examined individual changes for PD individuals relative to control surgery and control non-surgery peers.

RESULTS

Over two years we screened 152 older adult surgery or non-surgery candidates with 19 of these individuals having a diagnosis of PD. Final participants included 8 PD (5 surgery, 3 non-surgery), 47 Control Surgery, and 21 Control Non-Surgery. Eighty percent (4 of the 5) PD surgery declined greater than 1.645 standard deviations from their baseline performance on measures assessing processing speed and inhibitory function. This was not observed for the non-surgery PD individuals.

CONCLUSION

This prospective pilot study demonstrated rationale and feasibility for examining cognitive decline in at-risk neurodegenerative populations. We discuss recruitment and design challenges for examining post-operative cognitive decline in neurodegenerative samples.

Does preoperative carotid stenosis screening reduce perioperative stroke in patients undergoing coronary artery bypass grafting?

A number of institutions routinely perform carotid artery ultrasound screening before coronary artery bypass grafting (CABG) to identify carotid artery disease requiring revascularization before or during CABG, with the expectation of reducing perioperative neurologic events. The assumptions are that carotid disease is causally related to perioperative stroke and that prophylactic carotid revascularization decreases the risk of post-CABG neurologic events. Although carotid artery stenosis is a known risk factor for perioperative stroke in patients undergoing CABG, it might be a surrogate marker for diffuse atherosclerotic disease rather than a direct etiologic factor. Moreover, the benefit of prophylactic carotid revascularization in patients with asymptomatic unilateral carotid disease is uncertain. Therefore, we have reviewed the literature for evidence that preoperative carotid artery screening, by identifying patients with significant carotid artery stenosis and altering their management, reduces perioperative neurologic events in those undergoing CABG.

A comparison of off-pump and on-pump coronary bypass surgery in patients with low EuroSCORE

Background

The aim of the present study was to evaluate and compare postoperative short-term, mid-term and long-term outcomes of coronary artery bypass surgery performed with or without cardiopulmonary bypass in patients with a low European System for Cardiac Operative Risk Evaluation score.

Methods

A retrospective analysis of 478 consecutive low risk patients undergoing coronary bypass surgery between January 2002 and December 2007 was performed. Of these patients, 83 cases had undergone on-pump and 395 cases had undergone off-pump coronary bypass surgery. The patients were assessed in terms peri-operative complications, survival, mortality due to cardiac events, need for rehospitalization and repeated coronary revascularization.

Results

There was no significant difference between the two groups in terms of preoperative characteristics, except for chronic obstructive pulmonary disease. The number of distal anastomosis per patient was significantly lower in the off-pump group than in the on-pump group (2.66 ± 0.74 vs. 3.21 ± 0.85, p < 0.001). Early mortality rates were similar in both groups (1.01% for the off-pump group and 1.2% for the on-pump group, p = 0.687). Neurological complications were significantly lower in the off-pump group than in the on-pump group (1.1% vs. 6%, p = 0.01). The mean follow-up period was 80 ± 19.1 months (range, 3–112 months). The need for revascularization during long-term follow-up was 10.1% in the off-pump group and 7.2% in the on-pump group (p = 0.416). The 5-year survival was 95.2 ± 1.1% and 95.5 ± 2.7% in the off-pump and on-pump groups, respectively (p = 0.8), whereas the 7-year survival was 91.9 ± 1.6% and 84.7 ± 6.8% in the off-pump and on-pump groups, respectively (p = 0.274). The 5-year revascularization-free period was 89.5 ± 1.6% and 89.7 ± 3.5% in the off-pump and on-pump groups, respectively (p = 0.785). The 7-year revascularization-free period was 71.1 ± 3.1% and 73.5 ± 7.3% in the off-pump and on-pump groups, respectively (p = 0.075). The 7-year event-free survival was 80.1 ± 2.2% and 73.4 ± 7.3% in the off-pump and on-pump groups, respectively (p = 0.377).

Conclusions

The present study demonstrated that off-pump cardiac surgery had advantages over on-pump cardiac surgery in the short term; however, both interventions had similar mid-term and long-term outcomes, when performed in low-risk patient.

Nonpharmacologic stroke prevention in atrial fibrillation

Atrial fibrillation is associated with significant mortality and morbidity. The burden of morbidity in atrial fibrillation is mostly due to stroke, one of the major causes of death and the leading cause of long-term disability. Although highly effective in prevention of thromboembolic stroke, several factors limit utilization of chronic oral anticoagulation therapy. Eradication of atrial fibrillation and restoration of effective atrial contraction by surgical methods, or recently, by percutaneous catheter ablation methods, are two attractive approaches for stroke prophylaxis. Surgical exclusion of the left atrial appendage has generated considerable interest in the past decades and it is now performed routinely during mitral valve surgery in many centers. Recently, minimally invasive and percutaneous methods for the exclusion of left atrial appendage have been introduced. Currently, these approaches are being evaluated in ongoing trials. This review will discuss the current status of nonpharmacologic methods in the prevention of stroke in atrial fibrillation.

Low-dose spironolactone: effects on artery-to-artery vein grafts and percutaneous coronary intervention sites

The efficacy of vein grafts used in coronary and peripheral artery bypass is limited by excessive hyperplasia and fibrosis that occur early after engraftment. In the present study, we sought to determine whether low-dose spironolactone alleviates maladaptive vein graft arterialization and alters intimal reaction to coronary artery stenting. Yorkshire pigs were randomized to treatment with oral spironolactone 25 mg daily or placebo. All animals underwent right carotid artery interposition grafting using a segment of external jugular vein and, 5 days later, underwent angiography of carotid and coronary arteries. At that time, a bare metal stent was placed in the left anterior descending artery and balloon angioplasty was performed on the circumflex coronary artery. Repeat carotid and coronary angiograms were performed before euthanasia and graft excision at 30 days. Angiography revealed that venous grafts of spironolactone-treated animals had lumen diameters twice the size of controls at 5 days, a finding that persisted at 30 days. However, neointima and total vessel wall areas also were 2- to 3-fold greater in spironolactone-treated animals, and there were no differences in vessel wall layer thicknesses or collagen and elastin densities. In the coronary circulation, there were no differences between treatment groups in any vessel wall parameters in either stented or unstented vessels. Taken together, these observations suggest that low-dose spironolactone may exert a novel protective effect on remodeling in venous arterial grafts that does not depend on the reduction of hyperplastic changes but may involve dilatation of the vessel wall.

Timing of stroke after cardiopulmonary bypass determines mortality

BACKGROUND

Stroke is an important complication of cardiopulmonary bypass (CPB). This study determined if the timing of stroke events after CPB predicted stroke-related mortality or rehabilitation needs at hospital discharge.

METHODS

We performed a retrospective review of 7201 consecutive cardiac surgical patients during a 10-year period and identified 202 strokes. Postoperative stroke after CPB was classified as early (< or = 24 hours) or late (> 24 hours). Data were collected on patient characteristics, intraoperative variables and outcomes, postoperative course, stroke severity, and discharge status, including death from stroke. Logistic regression analysis was used to assess the relationship between the timing of stroke and discharge status after adjusting for clinically relevant factors.

RESULTS

The stroke incidence was 2.8%. Postoperative strokes occurred within 24 hours in 22.8% (46 of 202) and after 24 hours in 77.2% (156 of 202). Factors found in logistic regression analysis to be independently associated with stroke-related death included stroke within 24 hours postoperatively (odds ratio [OR], 9.16; p < 0.0001), preoperative chronic renal insufficiency (OR, 4.46; p = 0.01), and National Institute of Health Stroke Scale (NIHSS) score (OR, 1.16 per NIHSS point increase; p < 0.0001). Among survivors, early stroke was associated with greater rehabilitation needs (p < 0.001).

CONCLUSIONS

Early stroke after CPB is independently associated with higher stroke-related death and is associated with increased need for skilled rehabilitation at discharge. Neuroprotective strategies aimed at reducing early postoperative stroke may positively impact death and neurologic disability after CPB.

Risk Estimates of Stroke After Coronary Artery Bypass Graft and Carotid Endarterectomy

Neurologic complications of cardiovascular surgeries are well documented in the literature. Neurologic deficits may be mild and reversible or may be associated with permanent neurologic deficit. The incidence and severity of such complications vary according to the type of surgical procedure and usually correlate with patients' preoperative general medical condition, duration of surgeries, and intraoperative complications.

Relationship of Atrial Fibrillation and Stroke After Coronary Artery Bypass Graft Surgery: When is Anticoagulation Indicated?

BACKGROUND

Atrial fibrillation (AF) is considered as a risk factor for stroke after coronary artery bypass grafting operations.

METHODS

A retrospective search in our hospital's medical record database was done to identify patients with postoperative strokes who underwent coronary artery bypass grafting operations from January 1, 1993, until December 31, 2004. All cases were individually reviewed, and the temporal relationship between neurologic event and postoperative episodes of AF was determined. During the study period it was our consistent policy to use only Coumadin anticoagulation limited to patients who had persistent AF or were to be discharged in AF.

RESULTS

Of the 2,964 coronary artery bypass grafting operations, 576 patients (19.4%) had AF and 32 patients (1.1%) suffered stroke. Seventeen stroke patients maintained normal sinus rhythm during their hospital stay. Of the remaining 15 patients, 9 presented with neurologic deficit before the first episode of AF, with 5 having intraoperative and 4 having postoperative stroke. Of the 6 patients with AF before neurologic event, three strokes occurred within 1 week after spontaneous conversion to normal sinus rhythm. One patient with preoperative and also with intraoperative AF who underwent emergency coronary artery bypass grafting woke up with stroke. In the remaining two cases, the AF or atrial flutter episodes lasted less than 6 hours each before the neurologic event. More aggressive anticoagulation as suggested in the published guidelines could not have prevented strokes in any of these 6 patients.

CONCLUSIONS

This retrospective analysis does not support the use of aggressive anticoagulation, particularly full intravenous heparinization as a bridging therapy to decrease the already low incidence of postoperative strokes after routine coronary artery bypass grafting surgery.

Primary Prevention of Ischemic Stroke

Background and Purpose— This guideline provides an overview of the evidence on various established and potential stroke risk factors and provides recommendations for the reduction of stroke risk.

Methods— Writing group members were nominated by the committee chair on the basis of each writer’s previous work in relevant topic areas and were approved by the American Heart Association Stroke Council’s Scientific Statement Oversight Committee. The writers used systematic literature reviews (covering the time period since the last review published in 2001 up to January 2005), reference to previously published guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and when appropriate, formulate recommendations based on standard American Heart Association criteria. All members of the writing group had numerous opportunities to comment in writing on the recommendations and approved the final version of this document. The guideline underwent extensive peer review before consideration and approval by the AHA Science Advisory and Coordinating Committee.

Results— Schemes for assessing a person’s risk of a first stroke were evaluated. Risk factors or risk markers for a first stroke were classified according to their potential for modification (nonmodifiable, modifiable, or potentially modifiable) and strength of evidence (well documented or less well documented). Nonmodifiable risk factors include age, sex, low birth weight, race/ethnicity, and genetic factors. Well-documented and modifiable risk factors include hypertension, exposure to cigarette smoke, diabetes, atrial fibrillation and certain other cardiac conditions, dyslipidemia, carotid artery stenosis, sickle cell disease, postmenopausal hormone therapy, poor diet, physical inactivity, and obesity and body fat distribution. Less well-documented or potentially modifiable risk factors include the metabolic syndrome, alcohol abuse, drug abuse, oral contraceptive use, sleep-disordered breathing, migraine headache, hyperhomocysteinemia, elevated lipoprotein(a), elevated lipoprotein-associated phospholipase, hypercoagulability, inflammation, and infection. Data on the use of aspirin for primary stroke prevention are reviewed.

Conclusion— Extensive evidence is available identifying a variety of specific factors that increase the risk of a first stroke and providing strategies for reducing that risk.

Preoperative assessment and management to prevent complications during high-risk vascular surgery

OBJECTIVE

Most patients requiring vascular surgical reconstruction are at high risk for major morbidity and mortality, with certain vascular procedures at particularly high risk for complications. Although numerous comorbid conditions are precisely the risk factors that determine outcome, we review particular factors for each surgery that may be optimized to alter outcome and minimize postoperative complications.

DESIGN

Literature review.

RESULTS

Certain aspects of care are common to all vascular surgery procedures, including thoracoabdominal aortic aneurysm repair, pararenal and ruptured abdominal aortic aneurysm repair, mesenteric and renal revascularization, and carotid endarterectomy. Some factors that are important include careful preoperative assessment and optimization of cardiac, pulmonary, and renal function and volume status. In addition, the use of experienced teams during and after the procedure, as well as clear and continuous communication between all surgical team members, may improve outcome. Particular attention to procedural details is also crucial to achieving excellent results.

CONCLUSIONS

Patients needing vascular surgery often possess management challenges that increase the risk of perioperative complications. Meticulous attention to details during all phases of care, including preoperative optimization as well as intraoperative procedural conduct and communication, helps achieve optimal results and thus minimize the risk of complications.

Determination of etiologic mechanisms of strokes secondary to coronary artery bypass graft surgery

BACKGROUND AND PURPOSE

Current research focused on stroke in the setting of coronary artery bypass graft (CABG) surgery has missed important opportunities for additional understanding by failing to consider the range of different stroke mechanisms. We developed and implemented a classification system to identify the distribution and timing of stroke subtypes.

METHODS

We conducted a regional study of 388 patients with the diagnosis of stroke after isolated CABG surgery in northern New England from 1992 to 2000. Data were collected on patient and disease characteristics, intraoperative and postoperative care, and outcomes. Stroke etiology was classified into 1 of the following: hemorrhage, thromboembolic (embolic, thrombotic, lacunar), hypoperfusion, other (subtype not listed above), multiple (>or=2 competing mechanisms), or unclassified (unknown mechanism). The reliability of the classification system was determined by percent agreement and kappa statistics.

RESULTS

Embolic strokes accounted for 62.1% of strokes, followed by multiple etiologies (10.1%), hypoperfusion (8.8%), lacunar (3.1%), thrombotic (1.0%), and hemorrhage (1.0%). There were 54 strokes with unknown etiology (13.9%). There were no strokes classified as "other." Nearly 45% (105/235) of the embolic and 56% (18/32) of hypoperfusion strokes occurred within the first postoperative day.

CONCLUSIONS

We used a locally developed classification system to determine the etiologic mechanism of 388 strokes secondary to CABG surgery. The principal etiologic mechanism was embolic, followed by stroke having multiple mechanisms and hypoperfusion. Regardless of mechanism, strokes predominantly occurred within the first postoperative day.

Improvement and factors associated with improvement in quality of life during 10 years after coronary artery bypass grafting

AIM

To describe (1) the improvement in various aspects of quality of life (QoL) and (2) predictors of improvement, during 10 years after coronary artery bypass grafting (CABG).

PATIENTS AND METHODS

All patients who underwent CABG in western Sweden between June 1988 and June 1991 without simultaneous valve surgery and with no previous CABG were approached with an inquiry prior to and 5 and 10 years after the operation. QoL was measured with three different instruments: (1) Nottingham health profile (NHP), (2) psychological general well-being index (PGWBI) and (3) physical activity score (PAS).

RESULTS

There was a significant improvement in QoL with all three instruments from before to 10 years after the operation. The mean improvements +/-SD were for NHP, - 4.2+/-17.0 (P<0.0001), for PGWBI, +9.7+/-17.6 (P<0.0001) and for PAS, -0.96+/-1.23 (P<0.0001). However, there was also a deterioration with all three instruments between 5 and 10 years after surgery. The mean deteriorations +/-SD were for NHP, +4.4+/-12.8 (P<0.0001), for PGWBI, -4.6+/-14.8 (P<0.0001) and for PAS, +0.44+/-0.94 (P<0.0001). Independent predictors for an improvement in QoL with at least one of the instruments were low preoperative QoL, a younger age, being a man, high functional class (New York Heart Association), no hypertension, proximal left anterior descending coronary artery stenosis, short extracorporeal circulation time, use of internal mammary artery and a short postoperative time in the intensive care unit.

CONCLUSION

There is a higher estimated QoL 10 years after CABG than before, despite the fact that the patients are 10 years older. However, there is also a deterioration in QoL between 5 and 10 years after surgery. Predictors of improvement during the 10 years included age, sex, previous history, localization of stenosis, type of graft and preoperative and postoperative factors.

Intra- and postoperative predictors of stroke after coronary artery bypass grafting

BACKGROUND

Stroke is a devastating complication of coronary artery bypass graft surgery. An individual's risk of stroke is based in part on preoperative characteristics but also on intra- and postoperative factors. We developed a risk prediction model for stroke based on factors in intra- and postoperative care, after adjusting for a patient's preoperative risk.

METHODS

We conducted a regional prospective study of 11,825 consecutive patients undergoing coronary artery bypass graft surgery surgery from 1996 to 2001. Data were collected on patient and disease characteristics, intra- and postoperative care and course, and outcomes. Stroke was defined as "a new focal neurologic deficit which appears and is still at least partially evident more than 24 hours after its onset." Logistic regression identified significant predictors of stroke.

RESULTS

The incidence of stroke was 1.5%. The regression model significantly predicted the occurrence of stroke. As compared with cardiopulmonary bypass for less than 90 minutes, cardiopulmonary bypass for 90 to 113 minutes, odds ratio = 1.59, p = 0.022), cardiopulmonary bypass for 114 minutes or more (odds ratio = 2.36, p < 0.001), atrial fibrillation (odds ratio = 1.82, p < 0.001), and prolonged inotrope use (odds ratio = 2.59, p = 0.001) significantly improved our ability to predict stroke. Nearly 75% of all strokes occurred among the 90% of patients at low or medium preoperative risk.

CONCLUSIONS

The inclusion of factors associated with intra- and postoperative care and course significantly improved the prediction model. Most strokes occurred among patients at low or medium preoperative risk, suggesting that many of these strokes may be preventable. Reduction in stroke risk may require modifications in intra- and postoperative care and course.

Development and validation of a prediction model for strokes after coronary artery bypass grafting

BACKGROUND

A prospective study of patients undergoing coronary artery bypass graft surgery (CABG) was conducted to identify patient and disease factors related to the development of a perioperative stroke. A preoperative risk prediction model was developed and validated based on regionally collected data.

METHODS

We performed a regional observational study of 33,062 consecutive patients undergoing isolated CABG surgery in northern New England between 1992 and 2001. The regional stroke rate was 1.61% (532 strokes). We developed a preoperative stroke risk prediction model using logistic regression analysis, and validated the model using bootstrap resampling techniques. We assessed the model's fit, discrimination, and stability.

RESULTS

The final regression model included the following variables: age, gender, presence of diabetes, presence of vascular disease, renal failure or creatinine greater than or equal to 2 mg/dL, ejection fraction less than 40%, and urgent or emergency. The model significantly predicted (chi(2) [14 d.f.] = 258.72, p < 0.0001) the occurrence of stroke. The correlation between the observed and expected strokes was 0.99. The risk prediction model discriminated well, with an area under the relative operating characteristic curve of 0.70 (95% CI, 0.67 to 0.72). In addition, the model had acceptable internal validity and stability as seen by bootstrap techniques.

CONCLUSIONS

We developed a robust risk prediction model for stroke using seven readily obtainable preoperative variables. The risk prediction model performs well, and enables a clinician to estimate rapidly and accurately a CABG patient's preoperative risk of stroke.

Carotid stenosis: medical and surgical aspects

Medical treatment for carotid disease is similar to the treatment of atherosclerosis, with some recent data suggesting that there is a benefit to an aspirin-dipyridamole combination. CEA has revolutionized the treatment of symptomatic and asymptomatic carotid stenosis. This approach remains the gold standard for the surgical treatment of carotid artery stenosis, against which emerging modalities such as percutaneous carotid stenting should be compared. Higher-risk, asymptomatic patients can safely undergo CEA in high-volume centers for stenosis greater than 80% as defined by ultrasound.

Carotid artery disease and stroke during coronary artery bypass: a critical review of the literature

OBJECTIVES

to determine the role of carotid artery disease in the pathophysiology of stroke after coronary artery bypass (CABG).

DESIGN

systematic review of the literature.

RESULTS

the risk of stroke after CABG was 2% and remained unchanged between 1970-2000. Two-thirds occurred after day 1 and 23% died. 91% of screened CABG patients had no significant carotid disease and had a <2% risk of peri-operative stroke. Stroke risk increased to 3% in predominantly asymptomatic patients with a unilateral 50-99% stenosis, 5% in those with bilateral 50-99% stenoses and 7-11% in patients with carotid occlusion. Significant predictive factors for post-CABG stroke included; (i) carotid bruit (OR 3.6, 95% CI 2.8-4.6), (ii) prior stroke/TIA (OR 3.6, 95% CI 2.7-4.9) and (iii) severe carotid stenosis/occlusion (OR 4.3, 95% CI 3.2-5.7). However, the systematic review indicated that 50% of stroke sufferers did not have significant carotid disease and 60% of territorial infarctions on CT scan/autopsy could not be attributed to carotid disease alone.

CONCLUSIONS

carotid disease is an important aetiological factor in the pathophysiology of post-CABG stroke. However, even assuming that prophylactic carotid endarterectomy carried no additional risk, it could only ever prevent about 40-50% of procedural strokes.

Continuing controversy in the management of concomitant coronary and carotid disease: an overview

OBJECTIVES

To perform an analytical overview of the risk factors, pathogenesis of stroke and the strategies for the management of concomitant coronary artery disease and carotid artery stenosis (CAS). Four strategies were analysed; CABG in the presence of CAS, combined (CE+CABG), reverse (CABG+CE<3 months) and prior staged (CE+CABG<3 months).

METHODS

A literature search formed the basis of a reference database. Outcome was assessed by the 30-day permanent stroke and mortality rate for the different approaches. Accrued rates of permanent stroke and mortality rate were expressed in terms of mean stroke and mortality rate (MSR, MMR). Data was analysed comparatively and expressed in terms of P value, odds ratio and confidence limits.

RESULTS

33 different risk factors for stroke at CABG were identified. Significant factors included: ascending aortic atheroma, emergency procedures, impaired left ventricular function, cardioplegia and peripheral vascular disease. Risk of stroke at CABG increased with higher grade CAS (50 vs. 80%, P=0.009). Pathogenesis of stroke at CABG is multifactorial; the role of flow limiting CAS is controversial and other mechanisms are implicated. Analysis of the four strategies revealed that in the Prior Stage (n=573) the MSR was 1.5% and MMR 5.9%, in the Unprotected CABG+CAS series the MSR was 3.8% (n=840) and MMR (n=596) 4.4%, in the Reverse stage series (n=83) the MSR was 2.4%, and MMR 4.8%. For Combined procedures (n=3,295) the MSR was 3.9% and MMR 4.5%. Comparative analysis indicated a significant reduction in stroke for Prior vs. Combined (1.5 vs. 3.9%, P=0.007, odds 0.39, CI 0.2-0.77) with a higher mortality (5.9 vs. 4.5%, P=0.1, odds 1.41, Cl 0.96-2.06, NS). The stroke rate in the Prior stage also remained significantly lower compared to the Unprotected CABG group both mixed (P=0.015) and asymptomatic CAS (P=0.047). When total risks (MSR+MMR), were analysed, similar results were found between the groups; Prior 7.4%, Reverse stage 7.2%, Combined 8.4%, Unprotected CABG+ >50% CAS 11.5%.

CONCLUSIONS

Stroke at CABG is due to multiple risk factors, one of which is high-grade carotid stenosis. Pathophysiology of stroke, although multifactorial, supports embolism rather than flow limitation as the primary mechanism. Lack of randomised trials has made it impossible to draw firm conclusions regarding the best management strategy. There was no significant difference in the overall stroke and mortality risk between the various strategies, however, subgroup analysis suggests that, when carefully selected, patients do better by staging the operations. In our opinion patients without severe cardiac disease should be considered for Prior staging and the rest for Combined procedure. The role of reverse staging needs further evaluation.

Long term prognosis after CABG in relation to preoperative left ventricular ejection fraction

AIM

To evaluate the mortality rate, risk indicators for death, mode of death and symptoms of angina pectoris during 5 years after coronary artery by pass grafting (CABG) in relation to the preoperative left ventricular ejection fraction (LVEF).

PATIENTS

All patients in western Sweden who underwent CABG without concomitant valve surgery and without previously performed CABG between June 1988 and June 1991.

RESULTS

In all 1904 patients were included in the analysis, of whom 173 (9%) had a LVEF < 40%. Patients with LVEF > or = 40% had a 5-year mortality of 12.5%. LVEF < 40% was associated with an increased risk of death (RR 2.3; 95% cl 1.7-3.1). There was no significant interaction between age, sex or any other factor in terms of clinical history and LVEF. However, left main stenosis was a strong independent predictor of death among patients with LVEF < 40% but not in those with a higher LVEF. Patients with a low LVEF more frequently died a cardiac death and a death associated with myocardial infarction (AMI). Furthermore they more frequently died in association with congestive heart failure and ventricular fibrillation. Among survivors, symptoms of angina pectoris were similar regardless of the preoperative LVEF.

CONCLUSION

Patients with a low preoperative LVEF have a more than two-fold increased risk of death during 5 years after CABG. Their increased risk of death includes cardiac death, death associated with AMI, congestive heart failure and ventricular fibrillation.

Multicenter review of preoperative risk factors for stroke after coronary artery bypass grafting

BACKGROUND

Stroke complicates the postoperative course in 1% to 6% of patients undergoing coronary revascularization. There has been no large scale mandatory database reporting on the incidence of stroke after coronary revascularization.

METHODS

A multicenter regional database from the Bureau of Health Care Research Information Services, New York State Department of Health, on 19,224 patients who underwent coronary revascularization in 31 hospitals within New York State during 1995 was analyzed to determine the risk factors for postoperative stroke.

RESULTS

The incidence of postoperative stroke was 1.4% (n = 270). Hospital mortality for patients who had a stroke was 24.8%, compared with 2.0% for the rest of the patient population. Postoperative stroke increased the hospital length of stay threefold (27.9+/-1.9 versus 9.1+/-0.9 days, p<0.0001). Multivariable logistic regression identified the following variables to be significantly associated with a postoperative stroke: calcified aorta (p<0.0001; odds ratio [OR], 3.013), prior stroke (p = 0.0003; OR, 1.909), age (p<0.0001; OR, 1.522 per 10 years), carotid arterial disease (p = 0.002; OR, 1.590), duration of cardiopulmonary bypass (p = 0.0004; OR, 1.27 per 60 minutes), renal failure (p = 0.0062; OR, 2.032), peripheral vascular disease (p = 0.0157; OR, 1.62), cigarette smoking (p = 0.0197; OR, 1.621), and diabetes mellitus (p = 0.0158; OR, 1.373).

CONCLUSIONS

Postoperative stroke increases mortality and length of stay after coronary revascularization. Several risk factors can be identified, and some of these factors are potentially amenable to intervention, either before or during coronary revascularization, and should also influence patient selection.

Risk factors for early or delayed stroke after cardiac surgery

BACKGROUND

Stroke after cardiac surgery is a devastating complication that leads to excess mortality and health resource utilization. The purpose of this study was to identify risk factors for perioperative stroke, including strokes detected early after cardiac surgery or postoperatively.

METHODS AND RESULTS

Data were obtained from 2972 patients undergoing coronary artery bypass graft and/or valve surgery. Patients >/=65 years old and those with a history of symptomatic neurological disease underwent preoperative carotid artery ultrasound scanning. Intraoperative epiaortic ultrasound to assess for ascending aorta atherosclerosis was performed in all patients. New strokes were considered as a single end point and were categorized with respect to whether they were detected immediately after surgery (early stroke) or after an initial, uneventful neurological recovery from surgery (delayed stroke). Strokes occurred in 48 patients (1.6%); 31 (65%) were delayed strokes. By multivariate analysis, prior neurological event, aortic atherosclerosis, and duration of cardiopulmonary bypass were independently associated with early stroke, whereas predictors of delayed stroke were prior neurological event, diabetes, aortic atherosclerosis, and the combined end points of low cardiac output and atrial fibrillation. Female sex was associated with a 6.9-fold increased risk of early stroke and a 1.7-fold increased risk of delayed stroke. In-hospital mortality of patients with early (41%) and delayed (13%) strokes was higher than that of other patients (3%, P=0.0001).

CONCLUSIONS

Most strokes after cardiac surgery occurred after initial uneventful recovery from surgery. Women were at higher risk to suffer early and delayed perioperative strokes. Atrial fibrillation had no impact on postoperative stroke rate unless it was accompanied by low cardiac output syndrome.

Stroke in cardiac surgical patients: determinants and outcome

BACKGROUND

Despite improving outcomes in cardiac surgical patients, stroke continues to remain a major complication. Few prospective studies are available on postoperative stroke. The present study was conducted to elucidate the incidence and predictors of stroke in a large group of cardiac surgical patients.

METHODS AND RESULTS

Prospective data collected on 4,941 patients undergoing cardiac surgery were subjected to univariate and logistic regression analyses (98.4% men; 72% older than 60 years; 9.1% with history of prior stroke; 80.4% underwent isolated coronary artery bypass grafting). Stroke predictors include history of stroke and hypertension, older age, systolic hypertension, bronchodilator and diuretic use, high serum creatinine, surgical priority, great vessel repair, use of inotropic agents after cardiopulmonary bypass, and total cardiopulmonary bypass time (p < 0.05 for all comparisons). Median intensive care unit and hospital stays were longer, and hospital mortality and 6-month mortality were higher for patients with stroke (p < 0.001).

CONCLUSIONS

Stroke after cardiac surgical procedures is a morbid event. Identification of predictors and development of strategies to modify these factors should lead to a lower incidence of stroke.

[Preoperative magnetic resonance angiography findings and postoperative neurological complications in 93 cases of CABG with cardiopulmonary bypass]

Between February 1994 and January 1997, 102 of the 146 patients treated by coronary artery bypass grafting (CABG) had undergone magnetic resonance angiography (MRA) of the brain and neck before the operation, and arterial stenosis or occlusion had been detected in 38 (36.9%) of them. Two of these patients had complicating severe calcification of the ascending aorta, and CABG was performed without cardiopulmonary bypass (CPB). Seven patients without stenotic lesions on MRA were also treated by CABG without CPB for other complications. In addition to the 102 patients one patient had been found to have occlusion of the left common carotid artery and poor enhancement of the distal portion, and as a result we switched from CABG to percutaneous transluminal angioplasty (PTCA). We enrolled 93 patients in this study excluding these 10 patients. The patients were distributed into the three groups according to the MRA findings. Group C = no stenotic lesions (58 patients). Group S = stenosis of < 70% (26 patients), Group SS = stenosis of > or = 70% (9 patients). Enhancement distal to the stenotic or occlusive lesions was good in all patients in group S and SS. We then examined them for the incidence of postoperative neurological complications. There were no significant differences among the three groups in regard to age, male/female ratio, or incidence of hypertension and hyperlipidemia. In Group S, the incidence of diabetes was significantly higher than in the other Groups. The incidence of prior stroke was significantly higher and the number of coronary arteries affected was significantly larger in group SS than the other groups. There were no significant differences among the three groups with regard to intraoperative variables. The lowest mean arterial pressure on CPB was 44.3 +/- 7.4 mmHg, 48.0 +/- 8.8 mmHg, 46.3 +/- 7.8 mmHg in Group C, S, and SS, respectively, In all groups the lowest mean arterial pressure on CPB was below 50 mmHg. There were no significant differences among the three groups with regard to time to awaken and time to extubation. Two patients experienced transient conciousness disturbance after CABG, one in Group C, the other in Group SS, but no new lesions were detected by brain CT. Only one patient, in Group C. suffered a stroke and had a new lesion on brain CT a month after the operation. No strokes occurred in the perioperative period. In nine patients with good enhancement distal to the severe stenotic or occlusive lesion on MRA of the brain and neck the lowest mean arterial pressure on CPB was below 50 mmHg, but there was no postoperative neurological complications due to the low perfusion pressure on CPB. The results of this study suggested that CABG with CPB can be performed safely in patients with good enhancement distal to the stenotic or occlusive lesions on MRA of the brain and neck.

Aortocoronary saphenous vein graft disease: pathogenesis, predisposition, and prevention

Aortocoronary saphenous vein graft disease, with its increasing clinical sequelae, presents an important and unresolved dilemma in cardiological practice. During the 1st month after bypass surgery, vein graft attrition results from thrombotic occlusion, while later the dominant process is atherosclerotic obstruction occurring on a foundation of neointimal hyperplasia. Although the risk factors predisposing to vein graft atherosclerosis are broadly similar to those recognized for native coronary disease, the pathogenic effects of these risk factors are amplified by inherent deficiencies of the vein as a conduit when transposed into the coronary arterial circulation. A multifaceted strategy aimed at prevention of vein graft disease is emerging, elements of which include: continued improvements in surgical technique; more effective antiplatelet drugs; increasingly intensive risk factor modification, in particular early and aggressive lipid-lowering drug therapy; and a number of evolving therapies, such as gene transfer and nitric oxide donor administration, which target vein graft disease at an early and fundamental level. At present, a key measure is to circumvent the problem of vein graft disease by preferential selection of arterial conduits, in particular the internal mammary arteries, for coronary bypass surgery whenever possible.

Cardio-pulmonary-bypass time has important independent influence on mortality and morbidity

OBJECTIVE

To determine the influence of cardio-pulmonary-bypass-time on hospital mortality and ICU-morbidity in isolated CABG surgery.

METHODS

Between 1985 and 1994 perioperative data of 8578 consecutive CABG operations were prospectively collected. Seven variables: gender, redo vs. primary operation, elective vs. urgent surgery, age in 4 categories, use of IMA, number of distal anastomoses (> 4 vs. < = 4), and cardio-pulmonary-bypass-time in four categories were entered in multivariate logistic regression analysis and odds ratios for respective cardio-pulmonary-bypass-time-categories with regard to mortality, length-of-stay in the ICU and 8 ICU-complications were calculated. Bypass-time up to 90 min was the reference category, the other categories were from 1.5 to 2.5 h, 2.5 to 3.5 h, and longer than 3.5 h.

RESULTS

8337 operations had complete data. Mortality and ICU-morbidity were low. The odds ratios for mortality were 2.3 (P = 0.0094), 7.4 (P < 0.0001) and 20.7 (P < 0.0001) for ascending bypass-time-categories. The odds ratios for prolonged ICU-stay were 1.8 (P = 0.0002), 3.3 (P < 0.0001) and 7.9 (P < 0.0001) for ascending bypass-time-categories. For postoperative complications the same pattern was found: consequently higher odds ratios for longer bypass-time-categories.

CONCLUSION

The highly significant correlation between cardio-pulmonary-bypass-time-category and the occurrence of undesirable postoperative events is demonstrated by the consequent rise in odds ratios. This independent influence of cardio-pulmonary-bypass-time on outcome reflects both problems encountered during revascularisation and time-related influence of cardio-pulmonary-bypass on the human body. When a predictive model was created, CPBT proved to be a good predictor of undesirable postoperative events.

Screening carotid ultrasonography and risk factors for stroke in coronary artery surgery patients

BACKGROUND

The role of noninvasive carotid artery screening in relation to other clinical variables in identifying patients at increased risk of stroke after coronary artery bypass grafting was examined.

METHODS

Preoperative, intraoperative, and postoperative clinical data were prospectively collected for 1,835 consecutive patients undergoing first-time isolated coronary artery bypass grafting between March 1990 and July 1995, 1,279 of whom had screening carotid ultrasonography. All patients with postoperative neurologic events were identified and reviewed in detail. Average patient age was 65.3 years (range, 33 to 92 years), and 9.3% (171 patients) had a prior permanent stroke or transient ischemic attack. Hospital and 30-day mortality was 2.2% (41 patients). Forty-five patients (2.5%) had a transient or permanent postoperative neurologic event. The data were analyzed by stepwise logistic regression to determine the independent predictors of both significant carotid stenosis and stroke.

RESULTS

On multivariate analysis, the clinical predictors of significant carotid stenosis were age (p < 0.0001), diabetes (p = 0.0123), female sex (p = 0.0026), left main coronary stenosis greater than 60% (p < 0.0001), prior stroke or transient ischemic attack (p = 0.0008), peripheral vascular disease (p = 0.0001), prior vascular operation (p = 0.0068), and smoking (p < 0.0001). When all variables were evaluated for those patients who underwent noninvasive carotid artery screening, the independent predictors of postoperative neurologic event were prior stroke or transient ischemic attack (p < 0.0001), peripheral vascular disease (p = 0.0037), postinfarction angina pectoris (p = 0.0319), postoperative atrial fibrillation (p = 0.0014), carotid stenosis greater than 50% (p = 0.0029), cardiopulmonary bypass time (p = 0.0006), significant aortic atherosclerosis (p = 0.0054), postoperative amrinone or epinephrine use (p = 0.0054), and left ventricular ejection fraction less than 0.30 (p = 0.0744).

CONCLUSIONS

The etiology of postoperative stroke is multifactorial. Selective use of carotid ultrasonography is of value in identifying patients who are at greater risk of postoperative stroke independent of other variables and should be considered before coronary artery bypass grafting, particularly in patients with a history of neurologic event or peripheral vascular disease.

Appendage obliteration to reduce stroke in cardiac surgical patients with atrial fibrillation

BACKGROUND

Left atrial appendage obliteration was historically ineffective for the prevention of postoperative stroke in patients with rheumatic atrial fibrillation who underwent operative mitral valvotomy. It is, however, a routine part of modern "curative" operations for nonrheumatic atrial fibrillation, such as the maze and corridor procedures.

METHODS

To assess the potential of left atrial appendage obliteration to prevent stroke in nonrheumatic atrial fibrillation patients, we reviewed previous reports that identified the etiology of atrial fibrillation and evaluated the presence and location of left atrial thrombus by transesophageal echocardiography, autopsy, or operation.

RESULTS

Twenty-three separate studies were reviewed, and 446 of 3,504 (13%) rheumatic atrial fibrillation patients, and 222 of 1,288 (17%) nonrheumatic atrial fibrillation patients had a documented left atrial thrombus. Anticoagulation status was variable and not controlled for. Thrombi were localized to, or were present in the left atrial appendage and extended into the left atrial cavity in 254 of 446 (57%) of patients with rheumatic atrial fibrillation. In contrast, 201 of 222 (91%) of nonrheumatic atrial fibrillation-related left atrial thrombi were isolated to, or originated in the left atrial appendage (p < 0.0001).

CONCLUSIONS

These data suggest that left atrial appendage obliteration is a strategy of potential value for stroke prophylaxis in nonrheumatic atrial fibrillation.

Neurological outcome in coronary artery surgery with and without cardiopulmonary bypass

INTRODUCTION

The neurological complications of coronary artery surgery with cardiopulmonary bypass (CPB) have been extensively studied, but to our knowledge those without CPB (NCPB) have not been defined.

PATIENTS & METHODS

We prospectively examined 81 patients, before and up to seven days after surgery, to compare the neurological morbidity between patients subjected to coronary artery bypass graft (CABG) surgery with and without CPB. We analyzed demographic variables, risk factors and neurological examination including neuropsychological (NPS) tests using chi-square and non-parametric analysis (Mann-Whitney and Kruskal-Wallis).

RESULTS

Forty-eight patients (34M; median age = 62 yrs; median number of grafts = 3 and median total surgery duration = 300 min) operated with CPB and 33 without CPB (23M; median age = 64 yrs; median number of grafts = 2 and median total surgery duration = 240 min) differed only in relation to number of grafts (p = 0.0001) and surgery duration (p = 0.0001).

CONCLUSION

We found no difference in early neurological outcome in patients subjected to CABG with or without CPB.

Systemic gaseous microemboli during left atrial catheterization: a common occurrence?

OBJECTIVE

Gaseous microemboli during cardiac surgery have been implicated as a potential cause of postoperative neurologic injury. Any monitoring technique that exposes the systemic circulation to atmospheric pressure could introduce gaseous microemboli, causing cerebral microembolization. The incidence of carotid artery gaseous microemboli was studied during left atrial catheter insertion.

DESIGN

Prospective clinical study.

SETTING

Tertiary care university hospital.

PARTICIPANTS

Twelve patients undergoing elective cardiac surgery.

INTERVENTIONS

Perioperatively, a 5-MHz continuous wave Doppler probe was positioned over the left carotid artery to maximally record blood flow signals. The criteria used for detecting a gaseous microembolus were a sudden increase in the amplitude of the visual signal by 30% and a characteristic audible sound.

MEASUREMENTS AND MAIN RESULTS

Numbers of microemboli at three timepoints (before and during left atrial catheter insertion and during catheter flushing) were assessed using the Friedman test. No emboli were detected before left atrial catheter insertion. When compared with the preinsertion time period, statistically (p < 0.05) significant numbers of gaseous microemboli were found in six patients during catheter insertion (3 +/- 1 microemboli; range 1 to 7 microemboli) and in five patients during catheter flushing (5 +/- 2 microemboli; range 1 to 12 microemboli). There was a tendency for patients with lower filling pressures to entrain more microemboli during insertion (r = 0.44; p = 0.149). No patient showed evidence of gross neurologic dysfunction postoperatively, although sensitive neurologic testing was not performed.

CONCLUSIONS

Left atrial catheter insertion and flushing can cause systemic gaseous microemboli in more than 50% of patients. Although the number of microemboli introduced is relatively small, extreme care should be used during left atrial catheter insertion.

Differential age effects of mean arterial pressure and rewarming on cognitive dysfunction after cardiac surgery

Central nervous system dysfunction is a common consequence of otherwise uncomplicated cardiac surgery. Many mechanisms have been postulated for the cognitive dysfunction that is part of these neurologic sequelae. The purpose of our investigation was to evaluate the effects of mean arterial pressure (MAP) during cardiopulmonary bypass (CPB) and the rate of rewarming on cognitive decline after cardiac surgery. Two hundred thirty-seven patients completed preoperative and predischarge neuropsychologic testing. MAP and temperature were recorded at 1-min intervals using an automated anesthesia record keeper. MAP area less than 50 mm Hg (time and degree of hypotension), as well as the maximal rewarming rate, were determined for each patient. Multivariable linear regression revealed that the rate of rewarming and MAP were unrelated to cognitive decline. However, interactions significantly associated with cognitive decline were found between age and MAP area less than 50 mm Hg on one measure, and between age and rewarming rate in another, identifying susceptibility of the elderly to these factors. Although MAP and rewarming were not the primary determinates of cognitive decline in this surgical population, hypotension and rapid rewarming contributed significantly to cognitive dysfunction in the elderly.

Predictors of cognitive decline after cardiac operation

Despite major advances in cardiopulmonary bypass technology, surgical techniques, and anesthesia management, central nervous system complications remain a common problem after cardiopulmonary bypass. The etiology of neuropsychologic dysfunction after cardiopulmonary bypass remains unresolved and is probably multifactorial. Demographic predictors of cognitive decline include age and years of education; perioperative factors including number of cerebral emboli, temperature, mean arterial pressure, and jugular bulb oxygen saturation have varying predictive power. Recent data suggest a genetic predisposition for cognitive decline after cardiac surgery in patients possessing the apolipoprotein E epsilon-4 allele, known to be associated with late-onset and sporadic forms of Alzheimer's disease. Predicting patients at risk for cognitive decline allows the possibility of many important interventions. Predictive power and weapons to reduce cellular injury associated with neurologic insults lend hope of a future ability to markedly decrease the impact of cardiopulmonary bypass on short-term and long-term neurologic, cognitive, and quality-of-life outcomes.

Cost-benefit analysis of transesophageal echocardiography in cardiac surgery

This article evaluates the costs and outcomes associated with TEE during and after cardiac surgery. The costs include the direct and indirect costs--the complications of TEE. The outcomes include the positive consequences or the benefits: money and lives saved. The article uses liberal (high) estimates of the direct and indirect costs of TEE and conservative (low) estimates of the benefits. The exact cost or benefit depends on the number of cases performed. The analysis shows that patients having surgery for congenital heart disease derive the greatest overall benefit: around $600 per case studied. Patients having valvular repair surgery derive the next greatest benefit: around $450 per case studied. In contrast patients having valve replacement have an overall cost of around $150 per case studied. Patients having surgery for coronary artery disease also derive an overall benefit: around $100-$300 per case studied, depending upon assumptions regarding TEE's role in prevention of intraoperative strokes. This analysis indicates that the financial benefits of TEE are substantial and frequently outweigh costs in patients requiring cardiac surgery.

Risk factors for stroke after cardiac surgery: Buffalo Cardiac-Cerebral Study Group

PURPOSE

The purpose of this study was to identify risk factors for stroke in patients undergoing heart surgery.

METHODS

A retrospective chart review of patients who underwent cardiac surgery in three hospitals of the State University of New York at Buffalo system over a 36-month period was completed. Demographics and risk factors were recorded, and stroke and death were determined by chart review. Carotid artery stenosis was determined by duplex examination. Data were analyzed by chi-squared and multiple logistic regression.

RESULTS

One thousand one hundred seventy-nine cases were analyzed, with a mortality rate of 2.3%, stroke rate of 1.6%, and combined stroke/death rate of 3.1%. Four variables were found to be associated with an increased risk of stroke: carotid artery stenosis greater than 50%, redo heart surgery, valve surgery, and prior stroke. Five variables were associated with increased mortality rates:; carotid artery stenosis greater than 50%, redo surgery, peripheral vascular disease, longer pump time, and hypercholesterolemia. Carotid artery stenosis greater than 50% was present in 14.7% of cases. Carotid artery stenosis greater than 75% was not itself associated with increased stroke risk. Most strokes occurred more than 24 hours after surgery. Stroke distribution did not correlate with site of carotid artery stenosis greater than 50%.

CONCLUSIONS

Most neurologic events after heart surgery occur in a subset of patients who can be defined before operation. Whereas carotid artery stenosis greater than 50% is a strong risk factor, the role of prophylactic endarterectomy is unclear. Future studies should focus on this high-risk subgroup. A prospective study of prophylactic carotid endarterectomy in patients undergoing coronary artery bypass grafting is needed.