Off-pump versus on-pump coronary artery bypass surgery and postoperative renal dysfunction

Renal dysfunction is a serious complication after coronary bypass surgery with cardiopulmonary bypass (CABG). Because duration of cardiopulmonary bypass (CPB) is associated with renal outcome, it has been proposed that avoidance of CPB with off-pump coronary bypass (OPCAB) may reduce perioperative renal insult. We therefore tested the hypothesis that OPCAB is associated with less postoperative renal dysfunction compared with CABG surgery. With IRB approval, we gathered data for 690 primary elective coronary bypass patients (OPCAB, 55; CABG, 635). Perioperative change in creatinine clearance (DCrCl) was calculated by using preoperative (CrPre) and peak postoperative (CrPost) serum creatinine values, and the Cockroft-Gault equation (DCrCl = CrPreCl - CrPostCl). Univariate and linear multivariate tests were used in this retrospective analysis; P: < 0.05 was considered significant. Multivariate analysis did not identify OPCAB surgery as an independent predictor of DCrCl. However, previously reported associations of PreCrCl, age, and diabetes with DCrCl were confirmed. Power analysis demonstrated an 80% power to detect a 7.0 mL/min DCrCl difference between study groups. In this retrospective study, we could not confirm that OPCAB significantly reduces perioperative renal dysfunction compared with CABG surgery. Our findings suggest that reduction of renal risk alone should not be an indication for OPCAB over CABG surgery. Implications: Retrospective analysis did not identify any significant difference in perioperative change in creatinine clearance after coronary revascularization with cardiopulmonary bypass compared with off-pump coronary surgery.     

Early and midterm clinical outcome in patients with severe left ventricular dysfunction undergoing coronary artery surgery

BACKGROUND: Patients presenting with severe left ventricular (LV) dysfunction undergoing coronary artery surgery are at increased risk of perioperative morbidity and mortality. The present study investigated early and midterm outcomes in a consecutive series of patients with severe LV dysfunction undergoing coronary surgery at our institution. METHODS: Data on 5,195 consecutive patients undergoing coronary artery bypass grafting (CABG) alone (in-hospital mortality 1.35%) from April 1996 to August 2002 were prospectively recorded in the Patient Analysis and Tracking System. Two hundred and fifty patients (median age 65 years [interquartile range, 57 to 70]) with preoperative left ventricular ejection fraction less than 30% (74 off pump; 29.6%) were identified and early and midterm clinical outcomes analyzed. Propensity scores were used to take account of the imbalance in the distribution of prognostic factors between the on-pump and off-pump groups. RESULTS: Patients undergoing on-pump surgery were less likely to have current congestive heart failure, insulin-dependent diabetes, a history of hypertension, have had gastrointestinal tract surgery or an ulcer, or unstable angina. They had on average lower Parsonnet scores and New York Heart Association and Canadian Cardiovascular Score ratings. However they were more likely to have more extensive coronary artery heart disease and to require more grafts than those undergoing off-pump surgery. After adjustment for consultant team and propensity scores no differences between groups with regard to in-hospital mortality and morbidity were found. The only in-hospital outcome to show a significant difference after adjustment was the need for intraoperative inotropic support, which was higher in the on-pump group (odds ratio 5.1; 95% confidence interval 2.55 to 10.2; p < 0.001)). The median follow-up times for the on- and off-pump groups were 3.4 years and 1.4 years respectively. Three-year survival was higher with on-pump surgery (87% on-pump versus 73% off-pump) but this difference did not reach statistical significance after adjustment for prognostic variables (hazard ratio 0.54, 95% confidence interval 0.22 to 1.26, p = 0.16). CONCLUSIONS: In-hospital mortality and morbidity in patients presenting with severe LV dysfunction is low with comparable results with both on- and off-pump coronary artery surgery. Midterm clinical outcome is encouraging and seems to justify surgical revascularization for this high-risk group of patients.     

The perioperative management of dialysis for patients undergoing coronary artery bypass surgery with chronic renal failure

Several methods of dialysis have been employed to maintain the perioperative water-electrolyte balance caused by the disorders with chronic renal failure. We have experienced 13 cases of coronary artery bypass surgery with chronic renal failure, and employed hemodialysis (HD) in 5 cases, hemodialysis with extracorporeal ultrafiltration method (HD + ECUM) in 5 cases, continuous ambulatory peritoneal dialysis (CAPD) in 3 cases for perioperative management. The perioperative changes of the circulatory blood volume and the fluid-balance, were assumed by positive reaction with varied over 60 mmHg in systolic blood pressure or demanded over double dose of catecholamines in each observed terms until the next day of the patients extubated. The cases with HD or HD + ECUM have changed the blood pressure more frequently (HD cases = 21%, HD + ECUM cases = 19%) than the cases with CAPD (CAPD cases = 3%). We conclude that the each methods are available to manage perioperative dialysis to undergo coronary artery bypass grafting should be employed with some techniques, CAPD will be the most favorable method to maintain the fluid balance stably for patients with severe compromised cardiac function.     

Postoperative atrial fibrillation is a major cause of stroke after on-pump coronary artery bypass surgery

BACKGROUND: Atrial fibrillation, occurring after coronary artery bypass grafting (CABG), has been suggested to be associated with the development of postoperative stroke. However, it is not clear what is the incidence of atrial fibrillation-related postoperative stroke, the timing of its occurrence, and the outcome. These issues have been investigated in a consecutive series of patients who have undergone on-pump coronary artery bypass grafting (ONCAB). METHODS: Among 2,630 patients who underwent ONCAB, 52 patients (2.0%) experienced postoperative stroke and form the basis of the present study. RESULTS: Twelve patients (23.1%) died postoperatively. The ischemic cerebral event occurred after a mean of 3.7 days (range, 0 to 33). In 19 patients (36.5%), atrial fibrillation preceded the occurrence of neurologic complication. These patients experienced a mean of 2.5 episodes of atrial fibrillation before the occurrence of neurologic complication. The cerebrovascular event occurred after a mean of 6.0 days in patients in whom atrial fibrillation preceded it, after a mean of 1.2 days in those with calcified ascending aorta, and after a mean of 3.1 days in those without calcified ascending aorta or in whom atrial fibrillation did not precede the cerebrovascular complication (p < 0.0001). Stroke occurred a mean of 21.3 hours after atrial fibrillation. CONCLUSIONS: This study confirmed that atrial fibrillation, occurring after CABG, is a major determinant of postoperative stroke. Prevention of postoperative atrial fibrillation, and of formation of clots into the left atrium, may dramatically reduce the risk of postoperative stroke.     

Off-pump versus on-pump coronary artery bypass surgery and postoperative pulmonary dysfunction

OBJECTIVE: To investigate how off-pump coronary artery bypass grafting (CABG) affects postoperative pulmonary function when compared with on-pump CABG. DESIGN: Prospective clinical study. SETTING: University-affiliated teaching hospital. PARTICIPANTS: Adult patients (n = 39) undergoing elective coronary artery bypass surgery with or without cardiopulmonary bypass. INTERVENTIONS: Two groups of patients were compared: 19 consecutive patients undergoing off-pump CABG surgery and 20 consecutive patients undergoing conventional CABG surgery. MEASUREMENTS AND MAIN RESULTS: Pulmonary function tests (flow volume loops and lung volumes with plethysmography) were done preoperatively and 72 hours postoperatively. Arterial blood gases and PaO2/FIO2 were measured at various stages. Sequential chest x-rays were obtained and evaluated for pleural changes, pulmonary edema, and atelectasis. In both groups, PaO2/FIO2 ratios decreased progressively throughout the perioperative period, with no significant differences between the groups at any stage during the study. There was a significant decline in postoperative pulmonary function tests in both groups, but there was no difference between groups at 72 hours postoperatively. No differences were found in the time to extubation, atelectasis scores, or postoperative complications. CONCLUSIONS: Off-pump CABG does not confer major protection from postoperative pulmonary dysfunction compared with CABG surgery with CPB. Strategies for minimizing pulmonary impairment after CABG surgery should be directed to factors other than the use of CPB.