Abstract 3049: Clinical Outcomes after Urgent Coronary Artery Bypass Surgery in Patients on Clopidogrel: Are the Risks Tangible or Anecdotal?

Abstract

PURPOSE : Clopidogrel is indicated in acute and chronic coronary syndromes and often administered prior to angiography. These patients are often sent subsequently for coronary artery bypass grafting (CABG) surgery, where potential increase in bleeding risk must be balanced with risk of ongoing ischemia if CABG delayed. This study aimed to test the hypothesis that patients undergoing urgent CABG who received clopidogrel, versus those who did not, have worse bleeding outcomes and early mortality. METHODS : We reviewed 451 consecutive patients (04/2005–12/2006) who underwent urgent CABG at our institution: 262 never received clopidogrel pre-CABG, 189 received clopidogrel <5 days prior. The latter all received intraoperative antifibrinolytics. The primary endpoint was in-hospital death, massive transfusion (>10U PRBC) or massive blood loss (>2L chest-tube loss/24 hrs). RESULTS : Patient characteristics were comparable between groups. Prior MI (71% vs 46%), NYHA class 3– 4 (94% vs 81%) and prior PCI (22% vs 13%) were higher in the clopidogrel group (p<0.05). Cross-clamp time was statistically higher in the clopidogrel group (97±30 vs 90±28 min, p=0.02); cardiopulmonary bypass and total operative times were similar. There was no difference in the primary endpoint of in-hospital death or massive bleeding indices (clopidogrel: 7% vs no clopidogrel: 6%, p=0.9). Death, bleeding indices, renal failure, post-op MI and stroke, were no different even after adjusting for the date of stopping clopidogrel pre-CABG. Chart audit showed bleeding as a significant contributor to cause of deaths, was no different in either cohort. After multivariable regression analysis, clopidogrel or the duration it was stopped pre-CABG, were not predictors of outcomes (death, MI, stroke or chest reopening for bleeding). Significant independent predictors of the primary endpoint included pre-op renal dysfunction, peripheral vascular disease and pre-op hemoglobin. CONCLUSION : Clopidogrel, or the time it was stopped prior to CABG, was not a risk factor for in-hospital death, massive bleeding, or other poor early outcomes in patients undergoing urgent CABG. Practice measures such as the use of antifibrinolytic agents may ameliorate the adverse effects of clopidogrel.