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Aspirin and postoperative bleeding after coronary artery bypass grafting
Victor A Ferraris1, Suellen P Ferraris, Oji Joseph
1Division of Cardiothoracic Surgery, University of Kentucky College of Medicine, Lexington 40536-0084, USA. vferr2@uky.edu
Insights
Aspirin use before coronary artery bypass grafting (CABG) increases the risk of postoperative bleeding, especially in high-risk patients. Platelet function tests can identify individuals prone to excessive bleeding after aspirin therapy.
Area of Science:
- Cardiology
- Hematology
- Surgical Research
Background:
- Controversy exists regarding aspirin's association with postoperative bleeding after coronary artery bypass grafting (CABG).
- Previous studies have yielded conflicting results on the impact of aspirin on bleeding complications in CABG patients.
Purpose of the Study:
- To investigate the link between aspirin use and postoperative bleeding complications in CABG patients.
- To determine if a subset of patients exhibits aspirin hyper-responsiveness, leading to platelet dysfunction and increased bleeding risk.
Main Methods:
- Retrospective review of 2,606 CABG patients (1995-1999) to correlate aspirin use with transfusion needs.
- Prospective assessment of bleeding times and platelet function (PAR-1 receptor activity, monocyte binding) in aspirin users.
Main Results:
- Aspirin users comprised 63% of patients; 23.1% required transfusions versus 19% of non-users.
- Aspirin independently predicted transfusion needs in high-risk patients, with increased bleeding times and altered platelet function observed.
- Increased non-red blood cell transfusions and reexploration for bleeding were noted in aspirin users.
Conclusions:
- Aspirin is associated with a higher likelihood of postoperative bleeding in CABG patients.
- Platelet function testing can identify aspirin hyper-responders at increased bleeding risk.
- Preoperative assessment combining risk factors, bleeding times, and flow cytometry may guide management.
Objective:
To 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 Data:
Despite 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.
Methods:
Between 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 = 40), bleeding times were measured before and after aspirin use. Flow cytometry was performed in another cohort of patients with known heart disease (n = 30) to determine the effect of aspirin on platelet surface receptors.
Results:
During 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.
Conclusions:
The 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.