Preoperative Aspirin Use and Outcomes in Cardiac Surgery Patients

Cao L, Young N, Liu H, Silvestry S, Sun W, Zhao N, Diehl J, Sun J. Ann Surg 2012; 255:399–404

Reviewers: Henry Liu, MD; Michael Yarborough, MD; Francis A. Rosinia, MD
Tulane University Medical Center, New Orleans, Louisiana

Background

As an antiplatelet and anti-inflammatory agent, aspirin has been widely used in the prevention and treatment of thrombotic cardiac events. But the effects of preoperative aspirin use on the outcomes of cardiac surgery patients remain uncertain. In this study, Dr. Cao et al evaluated the effect of preoperative aspirin use on major outcomes in cardiac surgery patients.

Methods

This observational cohort study enrolled 4256 consecutive patients undergoing cardiac surgery in two tertiary medical centers. The 2868 patients met the inclusion criteria were divided into two groups: aspirin taking group (n=1923) and no aspirin group (n=945) 5 days before surgery. Data collected included demographics, patient history, medical record information, preoperative risk factors, preoperative medications, intraoperative data, postoperative cardiocerebral events, renal failure, and 30-day all-cause mortality. The main parameters were 30-day all-cause mortality, postoperative renal failure/dialysis required, and major adverse cardiocerebral events (MACE), including permanent or transient stroke, coma, perioperative MI, heart block, and cardiac arrest.

Results

Patients in the aspirin group presented with significantly more preoperative comorbidities than the non-aspirin group. However, with propensity scores adjusted and multivariate logistic regression, the results of this study showed that preoperative aspirin therapy (vs non-aspirin) significantly reduced the risk of 30-day mortality (3.5% vs 6.5%, OR: 0.611, 95% CI: 0.391–0.956, P = 0.031), postoperative renal failure (3.7% vs 7.1%, OR: 0.384, 95% CI: 0.254–0.579, P < 0.001), dialysis required (1.9% vs 3.6%, OR: 0.441, 95% CI: 0.254–0.579, P < 0.001), intensive care unit stay (mean 107.2 vs 136.1 h, P < 0.001) and a composite outcome-major adverse cardiocerebral events (8.7% vs 10.8%, OR: 0.662, 95% CI: 0.482–0.909, P = 0.011) in the patients undergoing cardiac surgery.
However, readmissions did not show a significant difference between the 2 groups (14.5% vs 12.8%, P = 0.944).

Conclusions

This study concluded that preoperative aspirin therapy is associated with a significant decrease in the risk of major cardiocerebral complications, renal failure, and intensive care unit stay and 30-day mortality. And preoperative aspirin does not increase the risk of readmissions in patients undergoing cardiac surgery.

Comments

This observational cohort study recruited a relatively large sample size, and the exclusion criteria are clearly defined; and all major outcomes achieved statistically significant differences between two groups, except readmission risk. This study may help change our practice by allowing preoperative aspirin to continue through perioperative period or prescribing aspirin to cardiac surgery patients preoperatively;
As mentioned in the discussion, most aspirin users were chronic users, does 1-2 doses of aspirin preoperatively benefit patients or not? How long do we need to prescribe aspirin to cardiac surgery patients for them to get the benefits is unclear.
This study did not seem to have adequately investigated the intraoperative and postoperative bleeding and transfusion requirement, which are the main traditional concerns of using platelet inhibitors preoperatively in cardiac surgery. Having similar readmission rate does not necessarily indicate aspirin did not increase intraoperative and postoperative bleeding and transfusion requirement.
If the mechanism of its diverse organ protections is related to its anti-inflammatory effects, can other anti-inflammatory agents like steroids achieve similar outcomes of lowering postoperative complications of cardiac surgery?
Can other potent antiplatelet drug like Plavix administered preoperatively achieve similar or even better protective effects? If so, how can we avoid intraoperative and postoperative bleeding concerns by adjusting timing or dosing strategies?