(CCSP015) CARDIOVASCULAR OUTCOMES WITH P2Y12 INHIBITORS AFTER CORONARY ARTERY BYPASS GRAFT SURGERY

Background: Patients who undergo coronary artery bypass graft (CABG) surgery remain at high risk for major adverse cardiovascular events (MACE) despite contemporary pharmacotherapy. Although commonly used, there is uncertainty whether P2Y12 inhibitors reduce MACE in these patients. This study aimed to evaluate the effects of P2Y12 inhibitors on MACE in patients who underwent CABG surgery.

METHODS AND RESULTS: This was a propensity-weighted, retrospective, population-based cohort study using data from linked administrative databases in British Columbia (BC) including Cardiac Services BC HEARTis, Population Data BC, and PharmaNet. These databases include all cardiac revascularization procedures, hospital admissions, and prescription data for the entire population of BC (roughly 5 million people). We included all adults who underwent CABG surgery in BC between 2002 and 2020. We excluded patients who underwent CABG surgery in the previous 10 years or filled a prescription for a P2Y12 inhibitor in the 12 months before surgery. The primary exposure was prescription for a P2Y12 inhibitor within 30 days after surgery. The primary outcome was time to MACE, defined as a composite of all-cause death, nonfatal myocardial infarction, and nonfatal ischemic stroke. Propensity weighting was used in Cox proportional hazards models to compare time to MACE in patients exposed versus unexposed to P2Y12 inhibitors, assessed at 1 and 5 years after CABG surgery. Results were stratified by history of heart failure.

In total, 15,439 patients were included. Mean age was 66 years, 83% were male, and 16% were prescribed a P2Y12 inhibitor within 30 days of CABG surgery. Fifty-seven percent had a previous myocardial infarction. Heart failure was present in 16% of the cohort. Ninety-seven percent of patients were on a statin and 95% were on a beta-blocker. There were 1627 MACE events during 5 years of follow-up. Median exposure time was 23 months.

After propensity weighting and adjustment for relevant covariates, exposure to P2Y12 inhibitors reduced the 1-year hazard of MACE in patients with and without heart failure (hazard ratio [HR] 0.29, 95% confidence interval [CI] 0.17-0.51 and HR 0.48, 95% CI 0.32-0.70, respectively). At 5 years of follow-up, these effects persisted in patients with and without heart failure (HR 0.58, 95% CI 0.40-0.79 and HR 0.68, 95% CI 0.55-0.83, respectively).

Conclusion: In this propensity-weighted observational study, use of P2Y12 inhibitors reduced the risk of MACE in a cohort of post-CABG surgery patients. These results support the use of P2Y12 inhibitors as preventive therapy in patients who undergo CABG surgery.