Aspirin and Postoperative Bleeding After Coronary Artery Bypass Grafting

Abstract

ObjectiveTo evaluate the relationship between aspirin ingestion and postoperative bleeding complications, and to test the hypothesis that there is a subset of patients who are aspirin hyperresponders with a proclivity toward platelet dysfunction. Summary Background DataDespite numerous retrospective and prospective analyses, it is still controversial as to whether aspirin ingestion before coronary artery bypass grafting (CABG) is associated with significant postoperative bleeding. MethodsBetween January 1995 and December 1999, the records of 2,606 consecutive patients undergoing CABG were reviewed to identify patients with a history of aspirin ingestion up until the time of surgery. Aspirin ingestion was correlated with postoperative blood transfusion using multivariate analysis. In a subset of preoperative aspirin users (n ϭ 40), bleeding times were measured before and after aspirin use. Flow cytometry was performed in another cohort of patients with known heart disease (n ϭ 30) to determine the effect of aspirin on platelet surface receptors. ResultsDuring the 5-year study period, 63% of the CABG patients were identified as aspirin users. Among these, 23.1% required blood transfusions compared with 19% for the nonusers. Non-red blood cell transfusions were more common in aspirin users, as was reexploration for bleeding. Stratification of these results according to the frequency of aspirin use showed that aspirin is an independent multivariate predictor of postoperative blood transfusion only in high-risk patients. In the prospective studies, aspirin treatment resulted in a significant increase in the template bleeding time, an increase in platelet PAR-1 thrombin receptor activity, and a decrease in the binding of platelets to monocytes. ConclusionsThe findings support the hypothesis that aspirin is associated with a greater likelihood of postoperative bleeding. A platelet function testing algorithm that combines preoperative risk factor assessment, template bleeding times, and flow cytometry may allow the identification of aspirin hyperresponders who are at increased risk for bleeding.

Bleeding risk assessment using multiple electrode aggregometry in patients following coronary artery bypass surgery

“…In the present study, only isolated CABG patients were included which enhanced the robustness of the results. Ferraris and coworkers supported the premise that enhanced platelet inhibition following ASA administration results in bleeding tendency [15]. Our findings suggest a similar phenomenon.…”

“…This can result in diminished bleeding tendency in group of patients with high residual platelet reactivity regardless of APT administered. On the other hand, there is evidence that certain patients have an accentuated response to the usual doses of preoperative aspirin that may result in increased perioperative blood loss requiring PRBC transfusion [15]. Those facts can argue that quantified platelet function can be predictive of transfusion requirements rather than administration of antiplatelet drugs per se.…”

Acquired Disorders of Platelet Function

“…A retrospective study of 1900 patients who had ingested aspirin within 12 hours of coronary artery bypass grafting (CABG) versus 706 who had not, showed a 4.1% increase in the need for red cell transfusion, an increase in the need for platelet and cryoprecipitate transfusion from 2.1% to 4.5% and an increase in the re-operation rate from 2.0% to 3.7%. 34 Studies of patients receiving clopidogrel within a few days of surgery have similarly demonstrated a significant increase in bleeding complications. A prospective study of 470 cardiac surgery patients, 91 of whom had received clopidogrel within 5 days of operation, found an increased relative risk of death, need for intraaortic balloon pump, arrhythmia, re-intubation and stroke in patients who had received clopidogrel, although the number of events was small.…”

Preoperative Prasugrel Discontinuation Management in Coronary Artery Surgery

“…Notably, for patients receiving dual antiplatelet therapy preoperatively, the role of aspirin should not be underestimated as it is well known that dual antiplatelet therapy provides more potent aspirin inhibitory effect [6], which in turn enhances the risk of bleeding attributable to aspirin effect [7]. Therefore, it seems reasonable to perform drugs specific platelets function testing using both ADP as well as arachidonic acid induced platelet function agonists.…”