Abstract 2279: A Comparison of Early and Long-Term Outcomes Following Off-Pump and On-Pump Coronary Artery Bypass Surgery: Variation by Renal Function

Abstract

Background: The two surgical strategies for coronary artery bypass graft (CABG) surgery are on-pump CABG and off-pump CABG (OPCAB). Earlier studies comparing these two strategies have shown only small differences in clinical outcomes. In light of the growing interest in tailored therapy, the identification of patient subset in which major differences in outcomes exist based on surgical strategy is highly important. Patients with impaired renal function may be a potential target because this patient subset is at increased risk for adverse cardiovascular outcomes. Methods: We analyzed data from 5550 consecutive patients undergoing isolated CABG surgery between 1999 and 2005 according to the surgical strategy and the estimated glomerular filtration rate (eGFR), which was calculated with the 4-point Modification of Diet in Renal Disease equation. Early outcomes were in-hospital mortality and postoperative morbidities; and long-term outcomes included total mortality, repeated revascularization, myocardial infarction (MI), and major adverse cardiac events (MACEs=total mortality or repeated revascularization or MI). These outcomes were compared after adjustment for differences in baseline risk factors among the patients. Results: 1543 (27.8%) patients had impaired renal function (eGFR<60ml/min/1.73 m 2 ). In this patient subset, OPCAB was associated with lower rates of 2 postoperative morbidities and comparable in-hospital mortality rate, but long-term outcomes appeared to be inferior for OPCAB with regard to total mortality [hazard ratio (HR) 1.662, 95%CI 1.037 to 2.664], repeated revascularization (HR 2.099, 95%CI 1.177 to 3.743), MI (HR 2.046, 95%CI 1.110 to 3.774), and MACEs (HR 1.834, 95%CI 1.236 to 2.722). Among patients with preserved renal function (eGFR≥60 ml/min/1.73 m 2 ), the analysis showed no significant differences in clinical outcomes between the two surgical strategies. Conclusions: We observed a significant heterogeneity in treatment effect of surgical strategy (off-pump/on-pump surgery) in relation to renal function. These data suggest that impaired renal function may identify a target patient subset that would be most likely to benefit from on-pump strategy.