title: Coronary artery bypass grafting with or without cardiopulmonary bypass in patients with preoperative non-dialysis dependent renal insufficiency: a randomized study.
abstract: OBJECTIVE
  Preoperative renal insufficiency is a predictor of acute renal failure in patients undergoing coronary artery revascularization with cardiopulmonary bypass. Off-pump coronary artery bypass grafting has been shown to be less deleterious than on-pump bypass in patients with normal renal function, but the effect of this technique in patients with non-dialysis dependent renal insufficiency in a randomized study is unknown.
  
  
  METHODS
  From August 2004 through October 2005, 116 consecutive patients with preoperative non-dialysis-dependent renal insufficiency (glomerular filtration rate measured using the Modification of Diet in Renal Disease equation [MDRD GFR] < or = 60 mL x min(-1) x 1.73 m(-2)) undergoing primary coronary artery bypass grafting were randomized to on-pump (n = 60) and off-pump (n = 56) groups. MDRD GFR and serum creatinine levels were measured preoperatively and postoperatively at days 1 and 5. The changes in renal function and clinical outcomes were compared between the two groups.
  
  
  RESULTS
  Preoperative characteristics were comparable between the two groups. The repeated-measures analysis of variance was performed on the data that showed worsening of renal function in the on-pump group compared with the off-pump group (serum creatinine, P < .000; glomerular filtration rate, P < .000). Further analysis of subgroups of patients with diabetes alone, hypertension alone, and combined hypertension and diabetes also showed significant deterioration renal function in the on-pump group compared with the off-pump group. In covariate analysis, diabetes has emerged as a significant covariate by serum creatinine criteria while compromised left ventricular function has emerged as a significant covariate by glomerular filtration rate criteria. These analyses showed that the use of cardiopulmonary bypass is significantly associated with adverse renal outcome (P < .000). Three patents required hemodialysis in the on-pump group and none in the off-pump group. The mean number of grafts per patient was 3.85 +/- 0.86 and 3.11 +/- 0.89 in the on-pump and off-pump groups, respectively (P < .001), but the indices of completeness of revascularization, 1.00 +/- 0.08 for off-pump coronary bypass and 1.01 +/- 0.08 for on-pump coronary bypass, were similar (P = .60).
  
  
  CONCLUSIONS
  This study suggests that on-pump as compared with off-pump coronary artery bypass grafting is more deleterious to renal function in diabetic patients with non-dialysis dependent renal insufficiency. MDRD GFR is a more sensitive investigation than serum creatinine levels to assess renal insufficiency in patients undergoing coronary bypass.
authors.affiliation: Division of Cardiothoracic Surgery, CARE Hospital, The Institute of Medical Sciences, Hyderabad, India.
authors.forename: Lokeswara Rao
authors.initials: LR
authors.lastname: Sajja
authors.forename: Gopichand
authors.initials: G
authors.lastname: Mannam
authors.forename: Rajasekara M
authors.initials: RM
authors.lastname: Chakravarthi
authors.forename: Sriramulu
authors.initials: S
authors.lastname: Sompalli
authors.forename: Shanti K
authors.initials: SK
authors.lastname: Naidu
authors.forename: Bhupathiraju
authors.initials: B
authors.lastname: Somaraju
authors.forename: Raghava Raju
authors.initials: RR
authors.lastname: Penumatsa
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D002315:Cardiopulmonary Bypass / Q000379:methods*; D015897:Comorbidity; D017023:Coronary Angiography; D001026:Coronary Artery Bypass / Q000379:methods* / Q000401:mortality; D047549:Coronary Artery Bypass, Off-Pump / Q000379:methods / Q000401:mortality; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D011336:Probability; D006435:Renal Dialysis; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy; D018570:Risk Assessment; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology; D015996:Survival Rate