Hydroxyethyl starch and change in renal function in patients undergoing coronary artery bypass graft surgery

BACKGROUND: Several case reports and clinical lore have suggested that exposure to the colloid hydroxyethyl starch may impair renal function, but few studies have systematically addressed this issue, and several have produced conflicting results. We sought to study the question in a formal analysis of postoperative change in renal function in patients undergoing coronary artery bypass graft (CABG) surgery. METHODS: We identified 238 consecutive patients who underwent CABG surgery at a large academic medical center. Glomerular filtration rate (GFR) was estimated using the Cockroft-Gault formula at baseline as well as on postoperative days 3 and 5. Linear regression analysis was used to study the relation between changes in GFR and intraoperative hydroxyethyl starch administration. Multivariate models controlled for potential demographic, clinical, and surgery-related confounders. RESULTS: Hydroxyethyl starch use was independently associated with a reduction in GFR on both postoperative days 3 and 5, with GFR declining by 7.2 mL/min/1.73 m2 on day 3 per unit of hydroxyethyl starch administered (95% CI, 1.7 to 12.7; P = 0.012), and by 6.6 mL/min/1.73 m2 on day 5 (95% CI, 1.2 to 11.9; P = 0.018). CONCLUSION: Intraoperative use of hydroxyethyl starch may be associated with modest impairment in renal function in patients undergoing CABG surgery. Randomized clinical trials will be necessary to confirm these findings and to further investigate their clinical implications.     

右美托咪定对老年患者冠状动脉旁路移植术后认知功能的影响

目的 观察右美托咪定对老年患者冠状动脉旁路移植术(coronary artery bypass graft,CABG)后认知功能的影响. 方法 择期行CABG的老年患者60例,年龄60岁～70岁,美国麻醉医师协会(ASA)分级Ⅱ或Ⅲ级,采用随机数字表法分为两组,右美托咪定组(D组)和生理盐水对照组(C组),每组30例.D组患者于麻醉诱导前静脉注射右美托咪定0.6 μg/kg(15 min),随后以0.2 μg· kg-1·h.速率输注至术毕;C组给予等容量生理盐水;其余麻醉措施两组相同.于麻醉后手术前(T1)、心肺转流(cardiopulmonary bypass,CPB)开始后30 min(T2)、CPB结束后30 min(T3)、术后6(T4)、24 h(T5)测定颈内静脉球部血清肿瘤坏死因子(tumor necrosis factor,TNF)-α、白细胞介素(interlukin,IL)-6水平及S100β蛋白浓度.分别于术前1d及术后第1、4、7天对患者进行简易精神状态量表(mini-mental state examination,MMSE)测验. 结果 T2～T5时,D组血清TNF-α、IL-6水平及S100β蛋白浓度明显低于C组(P＜0.05).与T1比较,T2～T5两组血清TNF-α、IL-6水平及S100β蛋白浓度均明显升高(P＜0.05).D组患者MMSE评分术后第4天[(25.2±1.4)分]、第7天[(26.6±13)分]明显低于术前1 d[(29.3±0.8)分],C组患者MMSE评分术后第4天[(23.2±1.0)分]、第7天[(25.6±1.3)分]也较术前1 d[(29.4±1.0)分]明显降低(P＜0.05).术后第4、7天,术后认知功能障碍(postoperative cognitive dysfunction,POCD)的发生率D组(36.7％、30％)均明显低于C组(46.7％、36.7％)(P＜0.05).结论 右美托咪定可降低CPB下行CABG的老年患者POCD的发生率,其机制可能与抑制炎性反应以及S100β蛋白表达有关.     

Prophylactic dialysis in patients with renal dysfunction undergoing on-pump coronary artery bypass surgery

BACKGROUND: Preoperative creatinine values higher than 2.5 mg/dL are associated with markedly increased risk for both mortality and morbidity in patients undergoing coronary artery bypass surgery. We aimed to determine the effects of prophylactic perioperative hemodialysis on operative outcome in patients with nondialysis-dependent moderate renal dysfunction. METHODS: Forty-four adult patients with creatinine levels greater than 2.5 mg/dL but not requiring dialysis underwent coronary artery bypass surgery with cardiopulmonary bypass. The patients were randomly divided into two groups. In group 1 (dialysis group, 21 patients), perioperative prophylactic hemodialysis was performed in all patients. Group 2 (23 patients) was taken as a control group and hemodialysis was performed only if postoperative acute renal failure was diagnosed. RESULTS: The hospital mortality was 4.8% (1 patient) in the dialysis group, and 30.4% (7 patients) in the control group (p = 0.048). Postoperative acute renal failure requiring hemodialysis was seen in 1 patient (4.8%) in the dialysis group and in 8 patients (34.8%) in the control group (p = 0.023). Thirty-three postoperative complications were observed in the control group for an early morbidity of 52.2% (12 patients) and 13 complications occurred in 8 patients in the dialysis group (38.1%). The average length of the intensive care unit and postoperative hospital stay were shorter in the dialysis group than in the control group (p = 0.005 and p = 0.023, respectively). CONCLUSIONS: Preoperative creatinine levels higher than 2.5 mg/dL, increase the risk of mortality and the development of acute renal failure and prolong the length of hospital stay after on-pump coronary artery bypass surgery. Perioperative prophylactic hemodialysis decreases both operative mortality and morbidity in these high-risk patients.     

Changing risk of patients undergoing coronary artery bypass surgery

The aim of the present study was to evaluate the changing risk of patients undergoing coronary artery bypass grafting (CABG). Residents of Oulu who underwent coronary angiography and/or revascularization from 1993 to 2006 formed the basis of this community-wide study. One thousand three hundred and forty-nine consecutive patients who underwent CABG have been included in the analysis on changing operative risk and results after CABG. A significant increase in the operative risk occurred in patients who underwent CABG (mean logistic EuroSCORE in 1278 patients: 1993-1997: 3.7%; 1998-2002: 4.6%; 2003-2006: 5.4%; P<0.0001). Thirty-day mortality decreased during the last period (1993-1997: 2.5%; 1998-2002: 3.0%; 2003-2006: 1.6%; P=0.49). The area under the ROC curve of logistic EuroSCORE (1993-1997: 0.86; 1998-2002: 0.78; 2003-2006: 0.99) for prediction of 30-day postoperative mortality markedly improved during the last study period. Despite the increased operative risk, off-pump coronary surgery was associated with lower immediate postoperative mortality rates. Contrary to on-pump surgery, immediate postoperative death occurred after off-pump surgery only in patients with additive EuroSCORE >or=6. The results of this study suggest that improved perioperative care as well as changes in operative strategy are positively faced with the increased burden of comorbidities and operative risk of patients currently undergoing CABG.     

Effect of N-acetylcysteine on pulmonary function in patients undergoing off-pump coronary artery bypass surgery

Background: Pulmonary dysfunction related to inflammatory response and radical oxygen species remains a problem in off‐pump coronary bypass graft surgery (OPCAB), especially in patients with reduced left ventricular (LV) function. The aim of this study was to evaluate the effect of N‐acetylcystein (NAC) on pulmonary function following OPCAB. Methods: Patients with LV ejection fraction ≤40% were randomly assigned to receive either a bolus of 100 mg/kg of intravenous NAC over a 15‐min period immediately after anesthetic induction, followed by an intravenous infusion at 40 mg/kg/day for 24 h (NAC group, n=24), or a placebo (control group, n=24). Hemodynamic and pulmonary parameters, and the incidence of acute lung injury (PaO₂/FiO₂<300 mmHg) were assessed and compared. Results: The pulmonary vascular resistance index (PVRI) did not change during mechanical heart displacement compared with the baseline value in the NAC group while it was significantly increased in the control group. Significantly less number of patients developed acute lung injury at 2 h after the surgery in the NAC group. The other pulmonary parameters and the duration of ventilator care were all similar. Conclusions: NAC demonstrated promising results in terms of mitigating the increase in PVRI during mechanical heart displacement and attenuating the development of acute lung injury in the immediate post‐operative period. However, NAC could not induce a definite improvement in the other important pulmonary variables including PaO₂/FiO₂ and Q_s/Q_t, and did not lead to a decreased duration of ventilatory care or length of stay in the intensive care unit.     

Comparison between serum creatinine and creatinine clearance for the prediction of postoperative mortality in patients undergoing major vascular surgery

BACKGROUND: Poor renal function prior to surgery is associated with increased risk for mortality in patients undergoing major vascular surgery. Traditionally, this function is assessed by serum creatinine concentration (SeCreat). However, SeCreat is also influenced by age, gender and body weight. Hence, creatinine clearance (C(Cr)) is considered to be a better reflection of renal function. This study was undertaken to explore the prognostic value of preoperative calculated Cc, compared to SeCreat for the prediction of postoperative mortality. PATIENTS AND METHODS: The study group comprised 852 consecutive patients who underwent elective major vascular surgery at the Erasmus Medical Center, Rotterdam. Preoperative C(Cr) was calculated based on the Cockroft-Gault equation using preoperative SeCreat, age, body weight and gender. Univariable logistic regression analyses were used to study the relation between preoperative SeCreat, C(Cr) and postoperative mortality. Furthermore, multivariable logistic regression analysis was applied to evaluate the additional predictive value of age, body weight and gender additional to SeCreat. The receiver operating characteristic (ROC) curve was determined to evaluate the predictive power of several regression models for perioperative mortality. RESULTS: Postoperative mortality was 5.9% (50/852) within 30 days of surgery. In a univariable analysis, 10 micromol/l increment of SeCreat were associated with a 20% increased risk of postoperative mortality (OR = 1.2, 95% CI, 1.1-1.3) with an area under the ROC curve of 0.64 (95% CI, 0.56-0.71). If age, gender and body weight were added, the area under the ROC curve increased to 0.70 (95% CI, 0.63-0.77; p < 0.001), indicating that these risk factors had additional prognostic value. Indeed, in a separate regression analysis 10 ml/min decrease in C(Cr) was associated with a 40% increased risk of postoperative mortality (OR = 1.4,95% CI, 1.2-1.5; ROC area: 0.70, 95% CI, 0.63-0.76). ROC curve analysis showed that the cut-off value of 64 ml/min for C(Cr) yielded the highest sensitivity/specificity to predict postoperative mortality. CONCLUSION: Preoperative SeCreat was strongly associated with postoperative mortality, and adding age, gender, and body weight to the model showed improved predictive power indicating that preoperative C(Cr) calculated with these data has additional prognostic value.     

Reoperative coronary surgery. Comparative analysis of 6591 patients undergoing primary bypass and 508 patients undergoing reoperative coronary artery bypass

During an 18-year period a consecutive series of 6591 patients underwent primary coronary bypass grafting and 508 patients underwent reoperative bypass. The mean patient age for the reoperative group was identical to that of the primary group, 59.8 years, but the mean age at initial operation for the reoperative group was 55.2 years. Mammary grafts were done at initial operation in 59% of patients who have had one operation versus only 46% of patients who subsequently required reoperation (p less than 0.001). The overall operative mortality rate was 2.0% (134/6591) for primary coronary bypass versus 6.9% (35/508) for reoperations (p less than 0.001). Patients with a reoperative interval of 1 to 10 years had a 6.0% (18/312) mortality rate, compared with 17.6% (13/74) for those in whom the interval between operations was greater than 10 years (p less than 0.01). Ventricular arrhythmias, excessive bleeding, prolonged ventilatory support, intraaortic balloon pump insertion (all p less than 0.05), and perioperative myocardial infarction (p less than 0.001) were all more prevalent after reoperations. Including perioperative mortality, the actuarial survival rate at 5 years was 80% for reoperations versus 90% for primary operations. The corresponding figures at 10 years were 65% and 75%. The probability of undergoing reoperation within 5 and 10 years was 0.034 +/- 0.003 and 0.055 +/- 0.005, respectively. Ten years postoperatively, 36% of patients having the initial operation had recurrent angina whereas 58% of the reoperative group had significant recurrent angina. Ten years after reoperation, 30% of operative survivors were free of heart-related morbidity and mortality compared with 50% of patients having a primary operation. Univariate analysis of factors increasing the probability of reoperation include the absence of a mammary graft and younger age at operation. Patients undergoing a second bypass operation represent a substantially higher risk subgroup than patients undergoing initial operation in terms of perioperative morbidity, mortality, decreased long-term survival, and decreased relief of recurrent cardiac morbidity.     

A multimodal approach to the prevention of postoperative stroke in patients undergoing coronary artery bypass surgery

BackgroundStroke is known to be multifactorial in origin. This study was designed to assess the effectiveness of a multimodal approach to preventing this complication in patients undergoing coronary artery bypass.MethodsOne thousand five hundred thirty consecutive coronary artery bypass patients operated on by a single surgeon from July 1994 to April 2008 were studied. Group 1 patients (n = 1,214) were operated on before 2004. Group 2 patients (n = 316) were operated on after 2004. In group 2 patients, epiaortic scanning, selective use of proximal anastomotic devices, and alternative cannulation were used. Off-pump coronary artery bypass (OPCAB) was used in 730 patients. On-pump coronary artery bypass (ONCAB) was used in 800 patients. Preoperative risk factors including age, cerebrovascular disease, peripheral vascular disease, hypertension, and diabetes were examined in all patients. The incidence of postoperative stroke was determined for group 1 and 2 patients and the individual cohorts of OPCAB and ONCAB patients.ResultsThe overall incidence of stroke was 1.6% (25/1,530). The postoperative incidence of stroke was 1.7% (21/1,214) in group 1 patients as compared with 1.3% (4/316) in group 2 patients. The incidence of postoperative stroke was 2.4% (19/800) in ONCAB patients as compared with 0.8% (6/730) in OPCAB patients (P < .05).ConclusionsOPCAB is an important tool for the prevention of postoperative stroke. Adjunctive techniques for the prevention of emboli from the ascending aorta may also reduce the risk of stroke in OPCAB and ONCAB 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.     

Preoperative and postoperative management of patients undergoing coronary artery bypass grafts

In the preoperative care of patients for coronary artery bypass grafting, emphasis is given to the need for good coronary arteriograms and left ventricular cineangiograms, and the proper timing of operation after these investigations. The special measures needed for dealing with unstable and variant angina are discussed, and it is recommended that betaadrenergic blocking drugs should not be discontinued before operation. Good postoperative care is easiest when the operation habeen correctly performed. The management of postoperative hypertension, arrhythmias, low output syndrome, and myocardial infarction is discussed. Following discharge from the hospital, it is important to minimize known risk indicators for coronary artery disease and to encourage the patient to achieve as complete functional rehabilitation as possible. Excellent relief of angina is obtained in about 80% of patients initially, but in those who have recurrence of chest pain postoperatively, the possibility of a second coronary artery bypass grafting operation may be considered. The need for long-term follow-up and aftercare of coronary artery surgical patients is stressed, so that the true benefit to the patient in terms of improved quality and quantity of life may be established.

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Résumé Dans la préparation préopératoire en vue d'un pontage coronaire, il est important d'avoir de bonnes coronarographies et une bonne ventriculographie gauche et il faut, entre ces examens et l'opération, un délai adéquat. Nous discutons les mesures spéciales à prendre en cas d'angor instable et variable. Il ne faut pas arrêter les drogues bêta-bloquantes avant l'intervention.Les soins postopératoires sont faciles lorsque l'opération a été bien faite. Nous discutons les thérapeutiques de l'hypertension postopératoire, des arythmies, des débits bas, d l'infarctus myocardique. Après la sortie de l'hôpital, le malade doit éviter tous les facteurs favorisant la maladie coronaire et il faut encourager une réhabilitation fonctionnelle aussi complète que possible. On atteint, au début, une sédation excellente de l'angor dans quelques 80% des cas. Chez ceux qui ont, après l'opération, une récidive de douleurs thoraciques, il faut envisager la possibilité d'un second pontage coronarien. Les opérés des coronaires doivent être suivis et traités pendant longtemps, pour que l'on puisse préciser le réel gain pour les malades aux points de vue durée et qualité de la survie.

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Philip K. Caves died suddenly on July 23, 1978.     

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.     

Haemodynamic effects of nifedipine in patients undergoing coronary artery bypass surgery

Forty patients scheduled for elective aortocoronary bypass surgery were entered in a double-blind study set up to compare the haemodynamic effects of 20 mg nifedipine (n = 20) and placebo (n = 20), both administered with the premedication. Global left ventricular function was normal in all patients. Anaesthesia was induced and maintained with standardized doses of fentanyl, flunitrazepam, and pancuronium together with 50% N2O. Cardiovascular responses to anaesthesia, intubation, skin incision, sternal retraction, and aortic manipulation were investigated. Throughout the study nifedipine produced a marked decrease in systemic vascular resistance. The reduction of left ventricular afterload was associated with an increase in cardiac index. In contrast to other reports, we observed no severe hypotension after nifedipine administration. Mean arterial pressure in patients from the nifedipine group was lower than in the placebo group only prior to anaesthesia. Since no negative drug interactions between nifedipine and the anaesthetic agents were observed, we conclude that the established cardiovascular benefit of nifedipine should be continued during anaesthesia.     

Pharmacokinetics of sufentanil in patients undergoing coronary artery bypass graft surgery

OBJECTIVE: To determine the pharmacokinetics of sufentanil in patients undergoing coronary artery bypass graft surgery. DESIGN: Prospective, multigroup study. SETTING: University-affiliated hospital. PARTICIPANTS: Patients with good left ventricular function undergoing elective surgery (n = 103). INTERVENTIONS: Sufentanil was administered by target-controlled infusion, with target effect-site concentrations ranging from 0.4 to 4.5 ng/mL. Isoflurane was administered as required to maintain stable hemodynamics. Sufentanil pharmacokinetics were determined by population modeling. The potential effects of gender, weight, different premedications (lorazepam, morphine-scopolamine, or clonidine), and coinduction with propofol on sufentanil pharmacokinetics were explored. MEASUREMENTS AND MAIN RESULTS: The first model determined was a simple 3-compartment model, without any covariates, which had these parameters: V(1) = 5.7 L, V(2) = 18.1 L, V(3) = 225 L, Cl(1) = 0.69 L/min, Cl(2) = 3.1 L/min, and Cl(3) = 1.4 L/min. The overall predictive ability during the entire pre-cardiopulmonary bypass period of this model was excellent, with virtually no bias (median prediction error, -0.4%) and good precision (median absolute prediction error, 18.4%). More complex models with the various premedications used or coinduction with propofol as covariates did not improve the predictive accuracy or precision compared with the simple 3-compartment model. Similarly, including either gender or weight as a covariate did not improve predictive ability. CONCLUSION: The authors have determined a pharmacokinetic model for sufentanil that can be used to maintain desired target concentrations of sufentanil before cardiopulmonary bypass, with a high degree of accuracy and acceptable variability. Concomitantly administered medications (lorazepam, morphine-scopolamine, clonidine, or propofol) do not appear to have any clinically important effects on distribution-phase sufentanil pharmacokinetics.     

Sevoflurane anesthesia did not affect postoperative cognitive dysfunction in patients undergoing coronary artery bypass graft surgery

Purpose The purpose of this study was to retrospectively examine whether sevoflurane anesthesia had any ameliorative effects on postoperative cognitive dysfunction in patients undergoing coronary artery bypass graft (CABG) surgery. Methods One hundred and nine patients underwent elective CABG surgery at our institution from May 1999 to May 2001. From May 1999 to August 2000, the main anesthetic regime used included a propofol infusion with no volatile anesthetic being administered during the surgery. From September 2000 to May 2001, the main anesthetic regime used was 1.5%–2.0% sevoflurane from the postinduction period until the end of the surgery. All patients underwent a battery of neurological and neuropsychological tests 1 day before and 6 months after the operation. Results The use of sevoflurane did not have any significant effects on the postoperative levels of cognitive dysfunction. In contrast, multiple logistic analysis showed that age [odds ratio (OR), 1.3; P = 0.047], diabetes mellitus (OR, 2.5; P = 0.03), and atherosclerosis of the ascending aorta (OR, 1.4; P = 0.047) appeared to be predictive factors of postoperative cognitive dysfunction. Conclusion This retrospective study showed no relationship between postoperative cognitive dysfunction and the use of sevoflurane.     

The association of epsilon-aminocaproic acid with postoperative decrease in creatinine clearance in 1502 coronary bypass patients

Renal dysfunction is a common serious complication after cardiac surgery. Reports of proteinuria and hyperkalemia after cardiac surgery with epsilon-aminocaproic acid (EACA) have therefore raised concerns for renal safety. Since EACA renders these markers unreliable, we used perioperative change in creatinine clearance (DCrCl) to test the hypothesis that EACA is associated with greater reductions in creatinine clearance after heart surgery, particularly for patients with renal disease. We evaluated data from all elective primary coronary bypass patients during EACA introduction at our institution (July 1, 1991-December 31, 1992; 10 g iv bolus pre-cardiopulmonary bypass, then 1 g/h for 5 h). DCrCl was calculated using preoperative (CrPre) and postoperative peak serum creatinine values, using the Cockroft-Gault equation. Patients with CrPre > or = 133 micromol/L were also separately analyzed. Evaluated patients (n = 1502, +/-EACA; 581/905, 16 exclusions) included 233 with CrPre > or = 133 micromol/L (+/-EACA; 98/135). Multivariate analyses confirmed several known risk factors, but no association between DCrCl and EACA in all patients (P: = 0.66), and the subgroup with CrPre > or = 133 micromol/L (P: = 0.42). Implications: In a large population of primary Coronary Artery Bypass Graft including a subset with preoperative renal dysfunction, there were no postoperative reductions in creatinine clearance attributable to epsilon-aminocaproic (EACA) administration. This retrospective study suggests that moderate epsilon-aminocaproic acid dosing during cardiac surgery is safe for the kidney; however, this inference is based on a single marker of renal dysfunction and requires prospective confirmation using a variety of tests of renal function.     

Obesity in diabetic patients undergoing coronary artery bypass graft surgery is associated with increased postoperative morbidity

BACKGROUND: Despite the fact that obesity is a known risk factor for cardiovascular disease, many studies have failed to demonstrate that obesity is independently associated with an increased risk of cardiovascular morbidity and mortality in nondiabetic patients undergoing coronary artery bypass graft surgery. The authors investigated the influence of obesity on adverse postoperative outcomes in diabetic and nondiabetic patients after primary coronary artery bypass surgery. METHODS: A retrospective cohort study of patients undergoing primary coronary artery bypass surgery (n = 9,862) between January 1995 and December 2004 at the Texas Heart Institute was performed. Diabetic (n = 3,374) and nondiabetic patients (n = 6,488) were classified into five groups, according to their body mass index: normal weight (n = 2,148), overweight (n = 4,257), mild obesity (n = 2,298), moderate obesity (n = 785), or morbid obesity (n = 338). Multivariate, stepwise logistic regression was performed controlling for patient demographics, medical history, and preoperative medications to determine whether obesity was independently associated with an increased risk of adverse postoperative outcomes. RESULTS: Obesity in nondiabetic patients was not independently associated with an increased risk of adverse postoperative outcomes. In contrast, obesity in diabetic patients was independently associated with a significantly increased risk of postoperative respiratory failure (odds ratio [OR], 2.26; 95% confidence interval [CI], 1.41-3.61; P < 0.001), ventricular tachycardia (OR, 2.27; 95% CI, 1.18-4.35; P < 0.02), atrial fibrillation (OR, 1.56; 95% CI, 1.03-2.38; P < 0.04), atrial flutter (OR, 2.38; 95% CI, 1.29-4.40; P < 0.01), renal insufficiency (OR, 1.66; 95% CI, 1.10-3.41; P < 0.03), and leg wound infection (OR, 5.34; 95% CI, 2.27-12.54; P < 0.001). Obesity in diabetic patients was not independently associated with an increased risk of mortality, stroke, myocardial infarction, sepsis, or sternal wound infection. CONCLUSION: Obesity in diabetic patients is an independent predictor of worsened postoperative outcomes after primary coronary artery bypass graft surgery.