Predictors of stroke risk in coronary artery bypass patients

Depression and cardiac morbidity 5 years after coronary artery bypass surgery

The purpose of this study was to determine whether depression 1 month after coronary artery bypass surgery would be associated with greater cardiac morbidity in patients 5 years later. The cardiac symptom most affected by depression was the recurrence of angina. Factors associated with a return of angina at 5 years were depression measured preoperatively, at 1 month, at 1 year, and at 5 years. Additional significant factors were male sex and a preoperative history of smoking, percutaneous transluminal coronary angioplasty, or cerebrovascular accident. When these factors were combined in multiple logistic regression analyses, the score on the Center for Epidemiologic Studies Depression Scale at 1 month was the most significant of all factors. The depression score at 1 month after coronary artery bypass surgery is an important indicator of cardiac morbidity up to 5 years later.

The risk of stroke following coronary revascularization -- a population-based long-term follow-up study

OBJECTIVE

To study the incidence and risk factors of stroke after coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA).

DESIGN

During 1983-1992, coronary revascularization procedures (n = 2160) were recorded in patients aged 35-64 years as part of the population-based FINMONICA Myocardial Infarction Register. The FINMONICA Stroke Register and National Hospital Discharge Register were used to ascertain subsequent stroke events in such patients.

RESULTS

During the average follow-up of 5.83 years, 155 patients (7.2%) had a stroke. The cumulative incidence of stroke was 1.55% in the first year after revascularization and varied between 0.8 and 1.4% during subsequent years. In Cox proportional hazard models the relative risk of stroke was 3.01 (p = 0.0007) for a previous stroke, 2.61 (p = 0.0001) for diabetes mellitus, 2.15 (p = 0.007) for low income (compared with high income), 2.06 (p = 0.03) for male sex, and 1.43 (p = 0.02) for a 10-year increment in age.

CONCLUSION

The incidence of stroke during the first year after revascularization was five times higher than among the age- and sex-matched general population. Patients with a previous stroke, diabetes mellitus, advanced age, male sex and low socioeconomic status need special attention because of increased risk of stroke after CABG or PTCA.

Predictors of stroke in the modern era of coronary artery bypass grafting: a case control study

BACKGROUND

Stroke is a rare but devastating complication after coronary artery bypass grafting (CABG) and its prevention remains elusive. We used a case control design to investigate the extent to which preoperative and perioperative factors were associated with occurrence of stroke in a cohort of consecutive patients undergoing myocardial revascularization.

METHODS

From April 1996 to March 2001, data from 4,077 patients undergoing CABG were prospectively entered into a database. The association of preoperative and perioperative factors with stroke was investigated by univariate analyses. Factors observed to be significantly associated with stroke in these analyses were further investigated using multiple logistic regression to estimate the strength of the associations with the occurrence of stroke, after taking account of the other factors.

RESULTS

During the study period, 4,077 patients underwent CABG and of these 923 (22.6%) had off-pump surgery. Forty-five patients suffered a perioperative stroke (1.1%). Overall there were 46 in-hospital deaths (1.1%), of whom 6 also suffered a stroke. Brain imaging of the stroke patients showed embolic lesions in 58%, watershed in 28%, and mixed in 14%. Multivariate regression analysis identified several preoperative factors as independent predictors of stroke, ie, age, unstable angina, serum creatinine greater than 150 mcg/ml, previous cerebrovascular accident (CVA), peripheral vascular disease (PVD), and salvage operation. When operative risk factors were added to the adjusted model, off-pump surgery was associated with a substantial, but not significant, protective effect against stroke (odds ratio = 0.56, 95% confidence interval 0.20 to 1.55). Survival for stroke patients was 93% and 78% at 1 and 5 years, respectively.

CONCLUSIONS

Overall incidence of stroke is relatively low in our series. Age, unstable angina, previous CVA, PVD, serum creatinine greater than 150 mcg/ml, and salvage operation are independent predictors of stroke. These factors should be taken into account when informing each individual patient on the possible risk of stroke and in the decision-making process on the surgical strategy.

Off-pump coronary artery bypass grafting decreases morbidity and mortality in a selected group of high-risk patients

BACKGROUND

The ideal indication for off-pump coronary artery bypass grafting (OPCABG) has yet to be defined. High-risk surgical patients may benefit the most when cardiopulmonary bypass (CPB), aortic cross clamping, and cardioplegic arrest are avoided. The aim of this study was to determine whether off-pump coronary artery bypass grafting might decrease the operative morbidity and mortality in a select group of high-risk patients with multivessel coronary artery disease.

METHODS

Utilizing a Parsonnet risk stratification model we analyzed prospectively collected data on a cohort of high-risk coronary artery disease patients, which were operated on with beating-heart technology by the same group of surgeons in a tertiary care university medical center. High-risk patients were defined as those with a Parsonnet score of 15 or greater.

RESULTS

Fifty-seven multivessel disease OPCABG patients (over a period of 2 years) had markedly increased Parsonnet scores (24.3 +/- 10.6). The average ejection fraction of the patients was 42% (+/-12.3) and their age ranged from 52 to 85 years (mean 70.6 +/- 10.4, 26% women). Unstable angina was present in 42 patients (74%) and 10 patients underwent OPCABG within 24 hours of the occurrence of acute myocardial infarction. In addition to severe coronary artery disease 32% of the patients presented with congestive heart failure, insulin-dependent diabetes (18%), renal failure (22%), peripheral vascular disease (31%), pulmonary disease (18%), and neurologic disorders (14%). An average of 2.6 +/- 0.9 grafts/patient were performed and the posterior descending artery or marginal branches of the circumflex artery or both were grafted in 90%. The 30-day mortality rate was 3.5% (n = 2).

CONCLUSIONS

OPCABG can be performed with a reasonable low morbidity and mortality in this select group of high-risk patients. OPCABG is a reasonable, and might even be preferable, operative strategy in this high-risk group of patients.

Risk factor analysis of early and delayed cerebral complications after cardiac surgery

OBJECTIVE

To report the incidence, severity, and possible risk factors for early and delayed cerebral complications.

DESIGN

Retrospective study.

SETTING

Linköping University Hospital, Sweden.

PARTICIPANTS

Consecutive patients who underwent cardiac surgery in the period July 1996 through June 2000 (n = 3,282).

INTERVENTIONS

A standard cardiopulmonary bypass (CPB) technique was used for most patients. Postoperative anticoagulant treatment included heparin or anti-Xa dalteparin. Patients undergoing coronary artery bypass graft surgery received acetylsalicylic acid, and patients undergoing valve surgery received warfarin.

MEASUREMENTS AND MAIN RESULTS

Cerebral complications occurred in 107 patients (3.3%). Of these, 60 (1.8%) were early, and 33 (1.0%) were delayed, and in 14 (0.4%) patients the onset was unknown. There were 37 variables in univariate analysis (p < 0.15) and 14 variables in multivariate analysis (p < 0.05) associated with cerebral complications. Predictors of early cerebral complications were older age, preoperative hypertension, aortic aneurysm surgery, prolonged CPB time, hypotension at CPB completion and soon after CPB, and postoperative arrhythmia and supraventricular tachyarrhythmia. Predictors of delayed cerebral complications were female gender, diabetes, previous cerebrovascular disease, combined valve surgery and coronary artery bypass graft surgery, postoperative supraventricular tachyarrhythmia, and prolonged ventilator support. Early cerebral complications seem to be more serious, with more permanent deficits and a higher overall mortality (35.0% v 18.2%).

CONCLUSION

Most cerebral complications had an early onset. The results of this study suggest that aggressive antiarrhythmic treatment and blood pressure control may imfurther prove the cerebral outcome after cardiac surgery.

Impact of aortic manipulation on incidence of cerebrovascular accidents after surgical myocardial revascularization

BACKGROUND

The impact of aortic manipulation on incidence of cerebrovascular accidents (CVAs) was evaluated in patients who underwent myocardial revascularization.

METHODS

From January 1988 to December 2000, 4,875 patients had coronary operations; 33 who survived less than 24 hours and 19 who had aortic cannulation without cross-clamping were excluded. According to the degree of aortic manipulation, patients were divided into two groups: group A, aortic cannulation, cross-clamping, with (A1, n = 597) or without (A2, n = 2,233) side-clamping, and group B, with (B1, n = 460) or without (B2, n = 1,533) side-clamping. Patients in group A (n = 2,830) were operated on with and patients in group B (n = 1,993) were operated on without cardiopulmonary bypass (CPB). Univariate and multivariate analyses were applied to identify independent predictors of higher incidence of CVAs.

RESULTS

Forty-nine patients (1.0%) had a postoperative CVA, 24 early and 25 delayed, with a 30-day mortality of 34.7%. Independent CVA predictors were low output syndrome, presence of extracoronary vasculopathy, conversion from off to on pump, and any aortic manipulation. This latter risk factor was significant in patients with extracoronary vasculopathy, but not in patients without. Side-clamping was not a risk factor in patients operated on with CPB, but it was in no-CPB cases. Patients in group B1 had the same CVA incidence as patients in group A2. Therefore CPB, per se, was not a risk factor for higher CVA incidence.

CONCLUSIONS

Aortic manipulation must be avoided in patients with extracoronary vasculopathy. Maintenance of a good hemodynamic status is crucial for any patient to reduce CVA incidence. Patients with extracoronary vasculopathy are at higher risk, and a correct surgical strategy should be tailored for each case. In no-CPB cases use of side-clamping provides the same CVA risk as in patients in whom CPB, aortic cannulation, and cross-clamping were used.

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.

Safety and efficacy of one stage off-pump coronary artery operation and carotid endarterectomy

BACKGROUND

Patients with concomitant occlusive disease of coronary and carotid arteries remain at high risk of perioperative stroke and myocardial infarction. Combined coronary artery bypass grafting on cardiopulmonary bypass and carotid endarterectomy has been shown to give good results for this category of patients. In the present study, we analyzed our results of off-pump coronary artery bypass grafting and carotid endarterectomy as a one-stage procedure.

METHODS

Between January 1997 and December 2000, 82 patients underwent combined off-pump coronary artery bypass grafting and carotid endarterectomy. All patients were evaluated by preoperative carotid duplex scanning and carotid angiography. All patients had more than or equal to 70% carotid artery stenosis. There were 35 asymptomatic patients (42.7%) and 47 symptomatic patients (57.3%). Carotid endarterectomy was performed before coronary artery bypass grafting in all the patients.

RESULTS

There were 66 males (80.5%) and 16 females (19.5%) with a mean age of 63+/-8 years. The average number of grafts was 3.4+/-0.8. There was no hospital mortality. One patient had perioperative myocardial infarction. None of the patients had stroke. One patient had transient neurologic deficit and 1 patient had temporary 12th nerve dysfunction; both recovered completely. There was no incidence of neck wound infection, although 1 patient developed neck hematoma that required reexploration. At a mean follow-up of 2.2+/-0.7 years, 1 patient required contralateral carotid endarterectomy and 1 patient died because of cardiac failure.

CONCLUSIONS

Combined off-pump coronary artery bypass grafting and carotid endarterectomy is a safe and effective procedure in patients with significant concomitant carotid and coronary artery disease.

Surgical Approaches to Coronary Artery Disease

In this rapidly evolving era of coronary surgery, technologic advances have allowed the development of new myocardial revascularization strategies. Although conventional coronary artery bypass grafting is being challenged by other promising surgical procedures such as off-pump coronary artery bypass grafting, it remains the gold standard in patients with multivessel disease. Accurate evaluations of these new procedures are ongoing to assess their effectiveness and to define their role in the armamentarium of myocardial revascularization.

Stroke after cardiac surgery: short- and long-term outcomes

BACKGROUND

Stroke remains a devastating complication of cardiac surgery, but stroke prevention remains elusive. Evaluation of early and long-term clinical outcomes and brain-imaging findings may provide insight into stroke prognosis, etiology, and prevention.

METHODS

Five thousand nine hundred seventy-one cardiac surgery patients were prospectively studied for clinical evidence of stroke. Stroke and nonstroke patients were compared by early outcomes. Data collected for stroke patients included brain imaging results, long-term functional status, and survival. Outcome predictors were then determined.

RESULTS

Stroke was diagnosed in 214 (3.6%) patients. Brain imaging demonstrated acute infarction in 72%; embolic in 83%, and watershed in 24%. Survival for stroke patients was 67% at 1 year and 47% at 5 years. Independent predictors of survival were cerebral infarct type, creatinine elevation, cardiopulmonary bypass time, preoperative intensive care days, postoperative awakening time, and postoperative intensive care days. Long-term disability was moderate to severe in 69%.

CONCLUSIONS

Stroke after cardiac surgery has profound repercussions that are independently related to infarct type and clinical factors. These data are essential for clinical decision making and prognosis determination.

Jugular bulb oxyhemoglobin desaturation, S100beta, and neurologic and cognitive outcomes after coronary artery surgery

We reported that a decline in cognitive performance 3 mo after coronary artery bypass grafting surgery is associated with palpable aortic atheroma, but not postoperative jugular bulb oxyhemoglobin saturation (SjO2) <50%. However, the effect of SjO2 on clinical neurologic findings is not known. S100beta is a possible surrogate biochemical marker of brain injury, and we report here the scored clinical neurologic findings in 98 patients from our previous study in relation to SjO2, cognitive performance, aortic atheroma, and S100beta. Patients underwent a scored neurologic examination and cognitive assessment the day before and 3 mo after coronary artery bypass grafting surgery. Intraoperatively, intermittent blood sampling was performed, and postoperatively, the area under the curve describing SjO2 <50% in relation to time was calculated from continuous jugular bulb reflectance oximetry. Palpation was used to assess the ascending aorta for the presence of atheroma. The jugular bulb concentration of S100beta was measured 6 h after completion of surgery. The neurologic score 3 mo after surgery did not correlate with either intra- or postoperative SjO2 (r = 0.111, P = 0.278; and r = -0.074, P = 0.467, respectively). The main determinant of neurologic score at 3 mo was the preoperative neurologic score (r(2) = 0.63, P < 0.001), whereas palpable atheroma of the ascending aorta made a small but significant contribution (r(2) = 0.034, P = 0.004). Neurologic and cognitive scores correlated before surgery (r = 0.226, P = 0.022) and at 3 mo after surgery (r = 0.348, P < 0.001). A preoperative neurologic deficit of two or more had a small but significant negative effect on cognitive performance at 3 mo (standardized beta = -0.097, P = 0.018). There was a significant univariate correlation between S100beta and the 3-mo neurologic score (r = -0.232, P < 0.05), but not a multivariate correlation (beta = -0.090, P = 0.156).

IMPLICATIONS

Intraoperative jugular bulb oxyhemoglobin saturation (SjO2) and postoperative SjO2 <50% do not have an important influence on long-term neurologic outcome after coronary artery bypass graft surgery. Subtle preoperative neurology is associated with long-term cognitive decline, and aortic atheroma is a risk factor for both cognitive and neurologic decline.

Time course of changes in jugular venous oxygen saturation during hypothermic or normothermic cardiopulmonary bypass in patients with diabetes mellitus

BACKGROUND

Preexisting diabetic mellitus is a risk factor determining postoperative neurological disorders. The present study assesses the effects of normothermic and hypothermic cardiopulmonary bypass (CPB) on jugular venous oxygen saturation (SjvO2)in patients with preexisting diabetic mellitus.

METHODS

Sixteen diabetic patients who underwent elective coronary artery bypass grafting surgery were randomly divided into two groups: Group DN (n=8, diabetic patients) underwent normothermic CPB (>35 degrees C), and group DH (n=8, diabetic patients) underwent hypothermic CPB (32 degrees C). Controls were 16 age-matched non-diabetic patients (normothemic group, CN: n=8; hypothemic group, CH: n=8). A 4.0 F fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb to continuously monitor SjvO2 values. Hemodynamic parameters and arterial and jugular venous blood gases were measured seven times.

RESULTS

Cerebral desaturation, which was defined as SjvO2 values below 50%, was observed during normothermic CPB in diabetic patients (at the onset of CPB: 46+/-3%, at 20 min after onset of CPB: 49+/-3%, means+/-SD, respectively). No cerebral desaturation occurred in diabetic and control patients during hypothermic CPB.

CONCLUSIONS

Patients with preexisting diabetes mellitus experienced cerebral desaturation during normothermic CPB.

Magnetic resonance imaging findings and postoperative neurologic dysfunction in elderly patients undergoing coronary artery bypass grafting

BACKGROUND

Small cerebral infarctions are common in elderly patients, but the association between the magnetic resonance imaging finding and neurologic dysfunction after coronary artery bypass grafting has not been evaluated.

METHODS

We determined, prospectively, whether varying degrees of abnormal findings on magnetic resonance images of the brain increased the incidence of preoperative cognitive decline, postoperative neuropsychological dysfunction, and stroke in 421 elderly patients (> or = 60 years) undergoing coronary artery bypass grafting.

RESULTS

Control patients (almost normal or leukoaraiosis, n = 212) had rates of postoperative neuropsychological dysfunction (7%) and stroke (1.4%); the small infarctions group (some small infarctions, n = 126) had rates of 13% and 5.6%, respectively; whereas patients with multiple infarctions (multiple small infarctions or broad infarctions, n = 83) had rates of 20% and 8.4%, respectively (p = 0.004, p = 0.013). In the group with multiple infarctions, 49 patients (59%) were asymptomatic and 21 patients (25%) had cognitive decline. Stepwise logistic regression analysis demonstrated that the significant predictors of multiple small infarctions or large infarctions were history of cerebrovascular disease, renal insufficiency, cognitive decline, and cerebral arteriosclerosis.

CONCLUSIONS

Multiple infarctions significantly increase the risk of neurologic dysfunction after coronary artery bypass grafting. Routine screening for preoperative cognitive decline should be performed to detect underlying ischemic cerebral disease in elderly patients.

S100B as a predictor of size and outcome of stroke after cardiac surgery

BACKGROUND

Stroke after cardiac surgery is a clinical problem with often fatal or disabling outcome. To assess severity and probable outcome in affected patients only from clinical and radiological examinations is difficult. The glial-derived protein S100B has been suggested to be a marker of cerebral ischemia, and increased blood concentrations of S100B have been shown to correlate with size of lesion and prognosis after stroke. We studied the validity of S100B as a predictor of size of brain lesion and median term outcome in a consecutive group of patients suffering from stroke after cardiac surgery.

METHODS

During a period of 17 months, 20 patients with clinical signs of postoperative stroke were investigated with S100B measurement, sampled at 5, 15 and 48 hours after surgery. All patients were examined with computed tomography or magnetic resonance imaging to confirm the diagnosis, and the size of cerebral infarction was estimated from the radiological examinations. The patients were followed up for survival 24 to 39 months after surgery.

RESULTS

S100B concentration in blood 48 hours after surgery correlated with the size of infarcted brain tissue (r = 0.68, p < 0.001). Nine patients had S100B levels exceeding 0.5 microg/L and a 2-year mortality of 78%, whereas the 11 patients with S100B below 0.5 microg/L had a mortality of 18%.

CONCLUSIONS

Increased S100B in patients with a stroke following cardiac surgery correlate with the size of infarcted brain tissue. High S100B levels 48 hours after surgery have a negative predictive value for median term survival.

Beating heart surgery or conventional CABG: are neurologic outcomes different?

Although there has been much debate about the causes of neurologic complications associated with coronary artery bypass grafting (CABG), there is good evidence linking such complications with some of the pathophysiologic changes associated with use of conventional cardiopulmonary bypass (CPB). Several studies indicate that it is possible to significantly lower risk of stroke and other central nervous system (CNS) morbidity in patients undergoing CPB for CABG by application of selected techniques and equipment modifications. The resurgence of interest in coronary revascularization by using beating heart surgery (BHS) offers a unique opportunity to evaluate neurologic outcome independent of CPB. Currently, BHS would appear to significantly reduce morbidity in the elderly and to decrease the costs and resource use in coronary revascularization patients. It is hoped that by understanding the mechanisms of CNS injury associated with CABG, techniques can be developed to decrease the risk of neurologic injury associated with coronary revascularization, whether or not CPB is used. Definitive conclusions regarding outcomes after best practice CPB or BHS await large-scale, risk-stratisfied multicenter trials.

Evaluation of neurologic assessment and outcomes in cardiac surgical patients

It is well recognized that cardiac surgery with cardiopulmonary bypass can potentially induce a wide spectrum of central nervous system (CNS) sequelae. Our awareness of the prevalence of these CNS complications is dependent on the validity of the available diagnostic methods. Current assessment methods designed to detect both focal and diffuse cerebral ischemia include neurologic examination, imaging techniques, biochemical markers, neuropsychologic assessment, and patient perceived outcomes. These techniques vary in their sensitivity and specificity, as well as feasibility for use in everyday clinical practice. There are currently only limited standardized methodologic guidelines for the assessment of CNS complications after cardiac surgery, which has resulted in considerable interstudy variability in the identification and reporting of outcomes. The application of clearly definable endpoints for reporting of CNS outcomes would be beneficial. The wealth of available data suggests that the incidence of overt CNS injury such as stroke has declined since the 1980s and is now approximately 2%, whereas evidence suggests that up to one third of cardiac surgery patients experience postoperative cognitive deficits. One of the clear strengths of the current era is the recognition of CNS injury associated with cardiac surgery, and the quest to improve our understanding of these outcomes. The application of more uniform assessment and reporting practices is surely vital to the continued advancement of cardiac surgery.

Recommendations for the outpatient surveillance of renal transplant recipients. American Society of Transplantation

Many complications after renal transplantation can be prevented if they are detected early. Guidelines have been developed for the prevention of diseases in the general population, but there are no comprehensive guidelines for the prevention of diseases and complications after renal transplantation. Therefore, the Clinical Practice Guidelines Committee of the American Society of Transplantation developed these guidelines to help physicians and other health care workers provide optimal care for renal transplant recipients. The guidelines are also intended to indirectly help patients receive the access to care that they need to ensure long-term allograft survival, by attempting to systematically define what that care encompasses. The guidelines are applicable to all adult and pediatric renal transplant recipients, and they cover the outpatient screening for and prevention of diseases and complications that commonly occur after renal transplantation. They do not cover the diagnosis and treatment of diseases and complications after they become manifest, and they do not cover the pretransplant evaluation of renal transplant candidates. The guidelines are comprehensive, but they do not pretend to cover every aspect of care. As much as possible, the guidelines are evidence-based, and each recommendation has been given a subjective grade to indicate the strength of evidence that supports the recommendation. It is hoped that these guidelines will provide a framework for additional discussion and research that will improve the care of renal transplant recipients.

Off-pump bypass surgery--experience of 250 cases

From April 1996 to October 1998, 250 patients with a mean age of 63 years (31-86 years) underwent coronary artery bypass grafting using the off-pump technique. The prime reason for using this technique was the need to minimize the surgical trauma by avoiding extracorporeal circulation. Fifty-seven percent of the patients had 1-vessel disease, 39% had 2-vessel disease and 4% 3-vessel disease. Sternotomy was performed in 196 patients and an anterior mini-thoracotomy in 54 patients. The mean number of coronary anastomoses was 1.5. Perioperative mortality was 0.4%. The first consecutive 87 patients underwent an early postoperative coronary angiography (days 1-5) revealing a graft patency of 96.5%. Five out of the 7 patients with occluded grafts subsequently underwent another intervention (surgical revascularization in 4 patients and percutaneous transluminal coronary angioplasty in one); 1.2% developed transmural myocardial infarction and 2.8% were reoperated upon for bleeding. The mean time of ventilatory support was 2.5+/-0.5 h. The mean ICU time for all patients was 12 h (0-10 days). The mean in-hospital time was 7 days (2-30 days). Coronary artery bypass surgery without the use of extracorporeal circulation is a safe procedure that can be performed with limited need for intensive care resources. However, long-term results remain to be investigated.

Blood S-100 protein concentration in children undergoing cardiac surgery

OBJECTIVES

To investigate plasma levels of the betabeta isomer of S-100 protein and to assess the relationship between post-cardiopulmonary bypass (CPB) levels of this marker and a variety of perioperative and patient factors in children undergoing cardiac surgery.

DESIGN

Prospective study.

SETTING

University hospital.

PARTICIPANTS

Twenty-five children.

INTERVENTIONS

Blood samples (2 mL) for S-100 determinations were collected after the induction of anesthesia, 30 minutes after aortic cross-clamping, 1 hour after the termination of CPB, and 5 and 24 hours after the operation. Electroencephalogram activity was recorded, and neurologic examination was performed on all children 1 day before and 10 days after the operation. Lowest values of nasopharyngeal temperature, mean arterial pressure, arterial carbon dioxide tension (PaCO2), pH, and hematocrit during CPB were recorded.

MEASUREMENTS AND MAIN RESULTS

The overall change in S-100 during the study period was found to be statistically significant (p < 0.0001). Correlation between deltaS-100 and age (r = -0.45; p = 0.04), body surface area (r = -0.63; p = 0.002), nasopharyngeal temperature (r = -0.55; p = 0.01), and PaCO2 (r = -0.55; p = 0.009) was statistically significant in infants and children. Multivariate regression analysis indicated significant effects of PaCO2 and body surface area on deltaS-100 levels and area under the curve values.

CONCLUSION

In contrast to newborns, infants and older children showed prominent increases in S-100 protein concentration. Lack of pathologic electroencephalogram findings and neurologic signs in the postoperative period precludes the clinical use of S-100 protein concentration as a sensitive marker of cerebral injury.

Variability in treatment advice for elderly patients with aortic stenosis: a nationwide survey in The Netherlands

OBJECTIVE

To determine how the decisions of Dutch cardiologists on surgical treatment for aortic stenosis were influenced by the patient's age, cardiac signs and symptoms, and comorbidity; and to identify groups of cardiologists whose responses to these clinical characteristics were similar.

DESIGN

A questionnaire was produced asking cardiologists to indicate on a six point scale whether they would advise cardiac surgery for each of 32 case vignettes describing 10 clinical characteristics.

SETTING

Nationwide postal survey among all 530 cardiologists in the Netherlands.

RESULTS

52% of the cardiologists responded. There was wide variability in the cardiologists' advice for the individual case vignettes. Six groups of cardiologists explained 60% of the variance. The age of the patient was most important for 41% of the cardiologists; among these, 50% had a high and 50% a low inclination to advise surgery. A further 24% were influenced equally by the patient's age and by the severity of the aortic stenosis and its effect on left ventricular function; among these, 62% had a high and 38% a low inclination to advise surgery. Finally, 23% of the cardiologists were mainly influenced by the left ventricular function and 12% by the aortic valve area. The presence of comorbidity always played a minor role.

CONCLUSIONS

There were systematic differences among groups of cardiologists in their inclination to advise aortic valve replacement for elderly patients, as well as in the way their advice was influenced by the patients' characteristics. These results indicate the need for prospective studies to identify the best treatment for elderly patients according to their clinical profile.

Left hemispheric strokes in coronary surgery: implications for end-hole aortic cannulas

BACKGROUND

Perioperative stroke (POS) is a devastating complication of coronary artery bypass grafting (CABG). Many studies have been published concerning risk factors and possible causes of POS but none have studied which side of the brain is more frequently involved. The finding of a strong preponderance of left-sided strokes calls into question some widely held theories as to the cause of POS and implicates end-hole aortic perfusion catheters as a major factor.

METHODS

During a 3-year period (1996 to 1998), prospective data were collected on all 2,217 consecutive CABG patients at one hospital (with surgery by different surgeons in different groups). Strokes were classified as perioperative (within 3 days of surgery) or late (beyond 3 days but during hospitalization).

RESULTS

There were a total of 51 strokes (2.3%): 21 left, 10 right, 7 bilateral, 7 lacunar, 1 brainstem, and 5 indeterminate. There were 18 major territorial perioperative strokes on the left side and 6 on the right side. Thus, 75% (18 of 24) of POS were left-sided. Stroke patients were significantly younger than nonstroke patients (66.3 +/- 10.52 versus 71.4 +/- 8.47 years, p = 0.009). Other demographic data did not differ significantly.

CONCLUSIONS

If aortic clamping, cannulation, or manipulation were responsible for most strokes, then right-sided strokes should predominate, as the innominate artery is closest to the source of such emboli. In contrast, end-hole aortic cannulas direct a high-velocity jet at the left carotid orifice and may be responsible for a large proportion of POS. Side-hole aortic cannulas may reduce the incidence of this complication.

One-year clinical outcome after minimally invasive direct coronary artery bypass

BACKGROUND

Minimally invasive coronary artery bypass (MIDCAB) is a new surgical technique by which the left internal mammary artery is anastomosed under direct visualization to the left anterior descending artery without cardiopulmonary bypass.

METHODS AND RESULTS

We followed all 274 patients who underwent MIDCAB from the time it was introduced at a single center. In-hospital and 1-year clinical events were source-documented and adjudicated. The in-hospital major acute cardiac event rate was 2.2%; this included a 1.1% mortality rate. At 1 year, the respective rates were 7.8% and 2. 5%. When compared with the initial 100 procedures, the subsequent 174 procedures had shorter vessel occlusion times (10+/-5 versus 14+/-6 minutes; P:=0.009), times to extubation (6+/-3 versus 14+/-10 hours; P:<0.001), and lengths of hospital stay (2.1+/-1.9 versus 3. 2+/-3.1 days; P:=0.04). Cumulative 1-year adverse cardiac events were 11% in the initial 100 cases and 6% in the subsequent 174 cases (P:=0.17).

CONCLUSIONS

Excellent clinical results can be achieved with the MIDCAB technique. The clinical adverse event rate may decrease with accumulated experience.

Postoperative neurologic assessment and management of the cardiac surgical patient

The neurologic evaluation of patients in the immediate postoperative period and postanesthetic state is unique and challenging. Neurologic assessment is complicated by the lingering residual effects of anesthetics as well as by the effects of narcotic analgesics, anxiolytics, and muscle relaxants, especially in ventilated patients. In this review we examine the suspected causes, clinical manifestations, diagnostic options, and intervention schemes for the common neurologic syndromes seen after cardiac operations.

Strategy for reduction of stroke incidence in coronary bypass patients with cerebral lesions. Early results and mid-term morbidity using pulsatile perfusion

OBJECTIVES

Cerebral complication is an important factor affecting the outcome after coronary artery bypass surgery under cardiopulmonary bypass. One of the causes for cerebral complication is preoperative cerebrovascular stenotic lesion. Here, we have studied the effect of pulsatile perfusion on the rate of cerebral complication due to a cerebrovascular lesion in patients undergoing coronary arterial bypass graft under cardiopulmonary bypass.

METHODS

261 consecutive elective patients underwent operation using cardiopulmonary bypass for management of the atherosclerotic ascending aorta. Group 1 consisted of 62 patients with a cerebrovascular stenotic lesion (> or = 75%) identified on a magnetic resonance angiogram or multiple cerebral infarction diagnosed using a computer tomogram. Group 2 consisted of 199 patients diagnosed with no significant cerebral lesion. In Group 1, the systolic blood pressure during cardiopulmonary bypass was maintained at a level of 80 mmHg by means of pulsatile flow. In Group 2, non-pulsatile perfusion was used as usual.

RESULTS

The overall hospital mortality was 1.5%, and no mortality was caused by a cerebral event. Only one patient in Group 1 suffered from temporary hemiparalysis. A cerebral complication occurred in only 1.6% in Group 1, and 0.4% overall. The actuarial freedom from cerebrovascular accident after 54 months was 84.4% in Group 1, and 96.2% in Group 2 (p = 0.0011).

CONCLUSIONS

Management of the atherosclerotic ascending aorta and the use of pulsatile perfusion were helpful in preventing cerebral injury during CABG.

Serum S100 protein as a marker of cerebral damage during cardiac surgery

The identification of a serum marker to assist in the diagnosis of cerebral injury after cardiac surgery is potentially useful. S100 protein is an early marker of cerebral damage. It is released after cardiac surgery performed under cardiopulmonary bypass (CPB). Its level is correlated with the duration of CPB, deep circulatory arrest and aortic cross-clamping. Increased levels of S100 protein are correlated with the age of the patient and the number of microemboli, especially during aortic cannulation. Perioperative cerebral complications such as stroke, delayed awakening and confusion are associated with increased levels of S100 protein directly after bypass and from 15 to 48 h after it. In addition, increased levels of S100 protein are related to neuropsychological dysfunction after cardiac surgery. S100 protein has early and late release patterns after CPB; the early pattern may be due to sub-clinical brain injury. The late release pattern may be due to perioperative cerebral complications. Patients undergoing intracardiac operations combined with coronary artery bypass surgery are more susceptible to brain injury and have higher levels of S100 after CPB. Furthermore, adults and children undergoing deep circulatory arrest are more susceptible to brain injury, in terms of higher S100 protein release after CPB. Serum S100 protein levels are reduced after using arterial line filtration and covalent-bonded heparin to coat the inner surface of the CPB circuit.

Perioperative stroke in coronary artery bypass surgery. Analysis of risk factors

The incidence of neurologic complications after coronary bypass surgery is steadily rising as older and sicker patients are increasingly being treated. To identify patients requiring special attention, we reviewed the records in 2263 consecutive cases of first-time coronary artery bypass grafting in 1993-1995, in order to find predictive factors for stroke. Significant factors in univariate analysis were patient age, peripheral vascular disease, cerebrovascular disease, renal failure (defined as serum creatinine > or = 150 micromol/l), aneurysmal disease of the abdominal aorta, stenosis of the left main coronary artery, urgent or emergency operation, NYHA class, cardiopulmonary bypass time, number of aortic anastomoses, intraoperatively detected loose or calcified atheromatosis of the ascending aorta, left ventricular venting, intra-aortic balloon counterpulsation, cardiac complications necessitating early reoperation, and perioperative myocardial infarction. In a multivariate analysis, age, renal failure, cerebrovascular disease, peripheral vascular disease, NYHA class, number of aortic anastomoses, perioperative myocardial infarction and intraoperatively detected loose atheromatosis of the ascending aorta remained significant.

Early outcome and graft patency in mammary artery grafting of left anterior descending artery with sternotomy or anterior minithoracotomy

BACKGROUND

The main objective of this study was to retrospectively compare early outcome and graft patency in patients who underwent coronary artery bypass grafting with the internal thoracic artery to the left anterior descending artery via an anterior minithoracotomy or median sternotomy and without the use of extracorporeal circulation.

METHODS

One hundred thirty consecutive patients were studied. Median sternotomy was performed in 77 patients and anterior minithoracotomy in 53 patients.

RESULTS

There were no differences in early clinical data or persistent postoperative pain between the groups. Early graft patency was 88% in the thoracotomy group and 96% in the sternotomy group (p = 0.3). Five of 7 patients who presented with a significant stenosis at the first coronary angiography had a normal angiogram at the reangiography. None of the patients with nonsignificant stenosis at the early coronary angiography had any clinical signs of ischemia or chest pain.

CONCLUSIONS

In our experience, anterior minithoracotomy and median sternotomy are different and distinguishable regarding early outcome and early graft patency. Most of the stenoses visualized at the early coronary angiography had vanished at a later coronary angiography, which makes the interpretation of the angiogram hazardous as a tool for the decision for redo procedure in the early postoperative period.

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.

Is diabetes mellitus a major risk factor in coronary artery bypass grafting? The influence of internal thoracic artery grafting on late survival in diabetic patients

OBJECTIVE

The presence of diabetes could possibly have an adverse influence on the late results of coronary artery bypass grafting (CABG). A retrospective observational risk-unadjusted estimation study was conducted to clarify the magnitude of this unfavorable influence of diabetes based on our experience at Juntendo University.

METHODS

Between January 1984 and December 1995, 1,618 primary CABG operations were performed and 99.0% of these patients were followed up for a mean period of 81.2 months with a maximal follow-up of 14 years. Among the 1,610 patients who were successfully followed up, 523 patients (32.5%) were diabetic and this cohort was compared with 1,087 nondiabetic patients regarding the patient profiles, perioperative outcome, and the long-term outcome.

RESULTS

Diabetic patients included a higher proportion of females, a greater preoperative presence of renal insufficiency, a higher rate of three vessel disease, and reception of a greater number of grafts (mean: 2.5 versus 2.4) and an internal thoracic artery graft (68% versus 58%). Hospital mortality was not significantly different (2.1% vs 1.0%: ns). An actuarial analysis revealed a significantly unfavorable long-term survival in the diabetic group (59.6%) at 14 years, compared with the nondiabetic group (73.4%), however diabetic patients with an internal thoracic artery graft had a favorable long-term survival (82.0%) at 13 years, and this finding was almost identical to that of nondiabetic patients with an internal thoracic artery graft (88.5%).

CONCLUSION

We conclude that the presence of diabetes appears to be a major risk factor in patients undergoing CABG. However, diabetic patients with an internal thoracic artery graft had a survival almost identical to that of nondiabetic patients with an internal thoracic artery graft.

Minimally invasive direct coronary artery bypass grafting in a patient with brainstem infarction

Brainstem infarction associated with the primitive trigeminal artery is rare. We describe the case of a 61-year-old man with an acute myocardial infarction as well as a brainstem infarction. The patient was referred for coronary artery bypass grafting. Minimally invasive direct coronary artery bypass grafting (left internal thoracic artery to the second diagonal branch anastomosis) could be safely performed 10 weeks after an episode of brainstem infarction.

Intraoperative physiologic variables and outcome in cardiac surgery: Part II. Neurologic outcome

BACKGROUND

The impact of alterable physiologic variables on neurologic outcome after coronary artery bypass grafting procedures is unknown. The purpose of this study was to determine whether minimum intraoperative hematocrit, maximum glucose concentration, or mean arterial pressure during cardiopulmonary bypass influences risk-adjusted neurologic outcome after coronary artery bypass grafting.

METHODS

Outcome data from 2,862 patients undergoing coronary artery bypass grafting were merged with intraoperative physiologic data. A preoperative stroke risk index was calculated for each patient. Variables found significant by univariate logistic regression were tested in a multivariable model to determine association with outcome.

RESULTS

The incidence of stroke or coma in the study population was 1.3%. After controlling for stroke risk and bypass time, only an index of low mean arterial pressure during bypass retained a significant inverse association with outcome (p = 0.0304).

CONCLUSIONS

This study found no evidence that glucose concentration or minimum hematocrit are associated with major adverse neurologic outcome. The association between lower pressure during bypass and decreased incidence of stroke or coma persisted in all risk groups. This points to mechanisms other than hypoperfusion as the primary cause of neurologic injury associated with cardiac surgery.

Stroke after coronary artery operation: incidence, correlates, outcome, and cost

BACKGROUND

Stroke is a major complication of coronary operation, with reported rates of postoperative cerebral dysfunction ranging from 0.4% to 13.8%. In this report, the incidence, correlates, outcomes, and costs of stroke in coronary operation were evaluated at Emory University between 1988 and 1996.

METHODS

Data were entered prospectively into a dedicated computerized database at Emory University and analyzed retrospectively. Univariate and multivariate analyses were utilized where appropriate.

RESULTS

Data from 10,860 patients undergoing primary coronary operation between 1988 and 1996 were analyzed. There were 250 patients not entered into the database. Stroke occurred in 244 (2.2%). Univariate predictors of stroke (p<0.05) included age, female gender, hypertension, diabetes, prior stroke, prior transient ischemic attack (TIA), and carotid bruits. Multivariate correlates included age (odds ratio 1.07) previous TIA (odds ratio 2.2), and carotid bruits (odds ratio 1.9), although the area under the Receiver Operating Characteristics (ROC) curve was only 0.69, suggesting limited ability to predict stroke. One and 5 year survival rates were 64% and 44% with stroke, and 94% and 81% without stroke, respectively. Among the stroke group, 23% of the patient population died before hospital discharge. The stroke group had a significantly longer length of hospital stay, as well as higher costs.

CONCLUSIONS

Stroke is a devastating complication of coronary operation, significantly increasing morbidity, mortality, and cost. Three independent variables were identified for predicting stroke, including age, previous TIA, and carotid bruits. Patients should be carefully screened for cerebrovascular disease to help prevent stroke and its associated morbidity.

Hypothermic circulatory arrest in octogenarians: risk of stroke and mortality

BACKGROUND

The proportion of patients in their ninth decade of life undergoing complex cardiovascular procedures has increased over the past decade. The purpose of this study is to quantify the potential for stroke and mortality associated with deep hypothermic circulatory arrest (DHCA) in this age group.

METHODS

At our institution, 251 adult patients had cardiovascular procedures that required DHCA since 1989. This included 20 patients 80 years of age or older (group I) and 231 patients less than 80 years (group II). Additionally, we analyzed 632 patients 80 years of age or older who underwent a variety of cardiovascular procedures since 1989 that required cardiopulmonary bypass but not DHCA (group III). Neurologic outcomes have been maintained in our database prospectively since 1991.

RESULTS

The 30-day mortality in group I was 5%, in group II 15.2%, and in group III 8.2%. The stroke rate was 20% in group I, 8.8% in group II, and 6.5% in group III.

CONCLUSIONS

DHCA can be performed with acceptable early mortality in patients in their ninth decade of life, but they are at an increased risk of stroke. Follow-up shows satisfactory late survival.

Longer duration of cardiopulmonary bypass is associated with greater numbers of cerebral microemboli

BACKGROUND AND PURPOSE

Many patients who undergo cardiac surgery assisted with cardiopulmonary bypass (CPB) experience cerebral injury, and microemboli are thought to play a role. Because an increased duration of CPB is associated with an increased risk of subsequent cerebral dysfunction, we investigated whether cerebral microemboli were also more numerous with a longer duration of CPB.

METHODS

Brain specimens were obtained from 36 patients who died within 3 weeks after CPB. Specimens were embedded in celloidin, sectioned 100 microm thick, and stained for endogenous alkaline phosphatase, which outlines arterioles and capillaries. In such preparations, emboli can be seen as swellings in the vessels. Cerebral microemboli were counted in equal areas and scored as small, medium, or large to estimate the embolic load (volume of emboli).

RESULTS

With increasing survival time after CPB, the embolic load declined (P<0.0001). (Lipid emboli are known to pump slowly through the brain.) Also with increasing time after CPB, the percentage of large and medium emboli became lower (P=0.0034). This decline is consistent with the concept that the emboli break into smaller globules as they pass through the capillary network. A longer duration of CPB was associated with increased embolic load (P=0. 0026). For each 1-hour increase in the duration of CPB, the embolic load increased by 90.5%.

CONCLUSIONS

Thousands of microemboli were found in the brains of patients soon after CPB, and an increasing duration of CPB was associated with an increasing embolic load.

Difficulties in the interpretation of coronary angiogram early after coronary artery bypass surgery on the beating heart

OBJECTIVE

The major objective of this study was to evaluate the findings in early postoperative coronary angiography in patients who underwent coronary revascularization on the beating heart without cardiopulmonary bypass.

METHODS

Eighty-four consecutive patients receiving 113 grafts were studied. A coronary angiography was performed 0 to 5 days postoperatively. All the grafts were reviewed and classified in the following way: grade A (unimpaired run-off); grade B1 (<50 stenosis); grade B2 (>50% stenosis); grade O (occlusion). A second coronary angiography was performed in patients with a stenosis grade B2, 4 to 30 months postoperatively. An exercise test was performed by patients with B1 stenosis.

RESULTS

Overall graft patency was 96% in the 113 grafts. None of the 14 patients with B1 stenosis in the early coronary angiography had any clinical signs of ischemia. Eight of the 12 patients who exhibited B2 stenosis either at the anastomotic site, in the graft or in the distal coronary artery at the first coronary angiography had a normal angiogram at the re-angiography.

CONCLUSION

A majority of stenoses visualized at the early coronary angiography could not be seen at a later coronary angiography, which makes the interpretation of the angiogram unreliable as a tool for the decision as to redo-procedure in the early postoperative period.

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.

Technical aspects of total revascularization in off-pump coronary bypass via sternotomy approach

BACKGROUND

Cardiopulmonary bypass and cardioplegic arrest result in known physiologic inflammatory, coagulopathic, and embolic states that may result in end-organ damage. Interest in off-pump complete coronary revascularization using sternotomy exposure is therefore increasing.

METHODS

Using specific surgical and anesthetic techniques, we have been able to achieve total revascularization using off-pump coronary artery bypass grafting procedures (OP-CAB) through a sternotomy approach. Exposure techniques and local stabilization are tailored to individual vessels and cardiac regions. Vascular control is achieved with silicone-elastomer loops, occluders, and shunts. Poor ventricular function, advanced age, and other comorbid conditions, in and of themselves, were not considered contraindications to OP-CAB. Cardiomegaly or situations of small, intramyocardial, or heavily calcified vessels were relative contraindications to OP-CAB.

RESULTS

Of 141 sternotomy OP-CAB cases, 132 (93.6%) were completely off-pump. The mean number of OP-CAB grafts per patient in the cases that were completely off-pump was 3.3 (range, 1 to 6). The 30-day operative mortality was 0%. There were four instances of intraoperative cardiac arrest, precipitated by vascular occlusion of the right coronary artery or manipulating a cardiomegalic heart. Advanced age (> or = 80 years) or profound ventricular dysfunction (ejection fraction < or = 0.25) was present in a considerable percentage of patients (10.6% and 9.9%, respectively).

CONCLUSIONS

Off-pump coronary artery bypass grafting is successful for total revascularization in large numbers of patients. Anatomic factors, including cardiomegaly and small, intramyocardial, or heavily calcified vessels are possible contraindications to OP-CAB. Patients at highest risk for undergoing cardiopulmonary bypass, including those of advanced age and having ventricular dysfunction, are precisely the ones in whom OP-CAB may be the most useful.

Determinants of cognitive change after coronary artery bypass surgery: a multifactorial problem

BACKGROUND

Several studies have investigated predictors of cognitive decline after coronary artery bypass grafting (CABG), but there is little consensus as to which specific factors are predictive of poor cognitive outcomes.

METHODS

We evaluated 127 patients undergoing CABG with standardized neuropsychological tests preoperatively, at 1 month and at 1 year. The outcome measure was a continuous variable reflecting change in z-scores for eight cognitive domains over time for individual patients. Univariate analyses were performed to evaluate the association between the demographic, operative, and postoperative factors and the cognitive outcome variables. Factors that were significant were included in a multiple linear regression analysis.

RESULTS

Among the medical history variables, diabetes was associated with change in executive functions and psychomotor speed. Some of the operative variables were associated with short-term changes, but none with the 1-year outcomes. For example, the surgeon's rating of degree of difficulty in selecting a cross-clamp site was associated with change in attention. Higher mean pump rate during the procedure was associated with improved performance on tests of language. The cognitive domains associated with medical variables were different from those associated with surgical variables, and the associations observed at 1-year were different from those seen at 1-month.

CONCLUSIONS

Change in cognition after CABG is associated with both medical and surgical variables. The specifics of these associations depend on the choice of time points after surgery. This suggests that there are multiple etiologies for these changes, with nonspecific effects of anesthesia and prolonged surgery interacting with the more specific effects of the surgical procedure itself.

Neurobehavioural sequelae of cardiopulmonary bypass

The development of coronary artery bypass grafting (CABG) and its effect on angina is the product of a series of technical and scientific advances. Despite these advances, however, adverse neurobehavioural outcomes continue to occur. Stroke is the most serious complication of CABG, but studies that have identified demographic and medical risk factors available before surgery are an important advance. Short-term cognitive deficits are common after CABG, but may not be specific to this procedure. However, deficits in some cognitive areas such as visuoconstruction persist over time, and may reflect parieto-occipital watershed area injury secondary to hypoperfusion or embolic factors. Risk factors for cognitive decline may be time dependent, with short-term studies identifying factors that differ from those of long-term studies. Patients with depression before surgery are likely to have persistent depression afterwards. However, depression does not account for the cognitive decline after CABG. Since CABG is increasingly done in older patients with more comorbidity, the challenge is to identify patients at risk of adverse neurocognitive outcomes and to protect them by modification of the surgical procedure or by effective medical therapy.

Individualized surgical strategy for the reduction of stroke risk in patients undergoing coronary artery bypass grafting

BACKGROUND

This study was designed to evaluate the efficacy of a protocol of systematic screening of the ascending aorta and internal carotid arteries and individualization of the surgical strategy to the ascending aorta and internal carotid arteries status in reducing the stroke incidence among patients undergoing coronary artery bypass grafting.

METHODS

On the basis of a pre- and intraoperative screening of the ascending aorta and internal carotid arteries, 2,326 consecutive patients undergoing coronary artery bypass grafting were divided in low, moderate, and high neurologic risk groups. In the high-risk group dedicated surgical techniques were always adopted and the reduction of the neurologic risk was considered more important than the achievement of total revascularization.

RESULTS

The incidence of perioperative stroke in the high-risk group was similar to those of the other two groups (1.1 versus 1.3 and 1.1%, respectively; p = not significant); however, angina recurrence was significantly more frequent in the high-risk group.

CONCLUSIONS

The described strategy allows a low rate of perioperative stroke in high-risk patients undergoing coronary artery bypass grafting. Whether the reduction of the neurologic risk outweighs the benefits of complete revascularization remains to be determined.

Neurobehavioral Outcomes of Cardiac Surgery

Since the inception of cardiac surgery, postoperative neurobehavioral complaints have prompted intensive studies of neurologic and cognitive outcomes. There is now a wealth of information on the incidence of stroke, delirium, depression, and cognitive outcomes after car diac procedures. Stroke risk models have been devel oped to identify patients at high risk. Delirium, although much less objectively studied, still occurs frequently in the immediate postoperative period, but its relationship to long-term cognitive outcome has not been resolved. Postoperative depression may not be as common as was previously thought, and may be related to mood status before surgery. Cognitive decline may be short- term for some aspects of brain function, but more prolonged or delayed in others. Despite these extensive studies, it is not clear whether some of these outcomes are related to the surgical procedure itself, rather than the use of general anesthesia in an older population of patients with extensive atherosclerotic disease. Inclu sion of appropriate control groups, longer term follow- up, and larger sample sizes in future prospective studies will improve the design of intervention studies in this patient population.

[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.

Preoperative risk models for minimally invasive coronary bypass: a preliminary study

OBJECTIVE

Available risk assessment models are designed for standard coronary artery bypass grafting. We hypothesized that minimally invasive coronary bypass could improve on predicted outcome in extremely high-risk patients (Parsonnet score > 20%) by the current risk models.

METHODS

From September 1996 to September 1997, 27 consecutive extremely high-risk patients underwent minimally invasive coronary bypass. Seventeen patients were male; age was 73 +/- 12 years, and 63% of patients were older than 75 years. Left ventricular ejection fraction was 33.7% +/- 15% and 63% had an ejection fraction of less than 35%. The predicted 30-day mortality according to the System 97 model was 25.6% +/- 11.3%. The Parsonnet risk score was 36.2% +/- 11%; the predicted length of stay in the hospital was 15.3 +/- 3 days. The predicted risk of stroke according to the Multicenter Perioperative Stroke Risk Index was 22.3% +/- 11.7%.

RESULTS

Minimally invasive coronary bypass was isolated in 20 patients and integrated with angioplasty and stenting in 7 patients. The observed 30-day mortality was 0% (P < .01 vs predicted): at an average follow-up of 10.8 +/- 4.1 months, 26 patients (96.3%) are alive without angina; one patient with acquired immunodeficiency syndrome died on postoperative day 40 of acute pancreatitis. No patient had a stroke or neurologic deficit (P < .01 vs predicted). Patency of internal thoracic artery anastomosis was confirmed by angiography in all 27 patients. No patient required reoperation. Eighteen patients (67%) were extubated in the operating room. The observed length of hospital stay after minimally invasive coronary bypass was 3.8 +/- 2.6 days (P < .01 vs predicted).

CONCLUSION

On the basis of our results on a relatively small series of patients, we suggest that risk models geared for standard coronary bypass grafting may not be appropriate for minimally invasive coronary bypass.

Brain damage after aortic arch repair using selective cerebral perfusion

BACKGROUND

Selective cerebral perfusion is one of the most popular methods for cerebral protection during aortic arch repair. However, causes of postoperative brain damage are not fully understood. We analyzed brain damage after aortic arch repair using selective cerebral perfusion for true aortic arch aneurysm in regard to preoperative cerebral infarction and intracranial and extracranial occlusive arterial disease.

METHODS

Over a 9-year period, 60 patients with true aortic arch aneurysm underwent aortic arch repair using selective cerebral perfusion. Postoperative brain damage was evaluated in regard to preoperative cerebral infarction detected by computed tomography, magnetic resonance imaging, or both in 50 patients and intracranial and extracranial occlusive arterial disease detected by digital subtraction angiography, magnetic resonance angiography, or both in 35 patients.

RESULTS

Seven (12%) of the 60 patients died within 30 days of operation. Postoperative brain damage occurred in 6 (10.5%) (3, coma, and 3, hemiplegia) of 57 patients; 3 patients who died without awakening were excluded. Preoperatively, old cerebral infarction was detected in 9 patients (18%), and silent cerebral infarction (lacunar infarction and leukoaraiosis) was diagnosed in 26 patients (52%). Postoperative brain damage occurred in 3 (33%) of the 9 patients with preoperative cerebral infarction and in 3 (23%) of 13 patients with negative preoperative brain findings; this excludes 2 patients who died without awakening. No patient with silent cerebral infarction had postoperative brain damage. Occlusive arterial disease was detected in 7 patients (20%). The incidence of brain damage in these patients was 71% (5/7), which was significantly greater than that of 4% (1/28) in patients without occlusive arterial disease (p < 0.001).

CONCLUSIONS

Silent cerebral infarction may not be a risk factor for postoperative brain damage. Preoperative evaluation of intracranial and extracranial occlusive arterial disease provides important information as to whether a patient might sustain brain damage after aortic arch repair using selective cerebral perfusion.