(VP018) CARDIOVASCULAR OUTCOMES WITH ANGIOTENSIN-CONVERTING ENZYME INHIBITORS AND ANGIOTENSIN RECEPTOR BLOCKERS AFTER CORONARY ARTERY BYPASS GRAFT SURGERY

Background: Despite contemporary preventive pharmacotherapy, patients who undergo coronary artery bypass graft (CABG) surgery remain at high risk for major adverse cardiovascular events (MACE) and death. Evidence to support the benefit of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers (ACEI/ARBs) post-CABG surgery is equivocal. We evaluated the effect of exposure to ACEI/ARBs on MACE in patients who underwent CABG surgery over an 18-year period in British Columbia (BC).

METHODS AND RESULTS: This was a propensity-weighted, retrospective, population-based cohort study using data from linked administrative databases in 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). All adults who underwent CABG surgery in BC between 2002 and 2020 were eligible for inclusion. Patients who had undergone CABG surgery in the previous 10 years or filled a prescription for an ACEI/ARB within 12 months before their surgery date were excluded. Primary exposure was prescription for an ACEI/ARB within 30 days post-CABG surgery. The primary outcome was time to MACE, defined as a composite of all-cause death, nonfatal myocardial infarction, and nonfatal ischemic stroke, using Cox proportional hazards models with propensity-weighting. The results were stratified by heart failure.

The cohort consisted of 15,439 patients, 6191 (40%) of whom were prescribed an ACEI/ARB within 30 days of CABG surgery. Median exposure time was 40 months. A total of 1627 MACE events occurred over the 5-year follow-up period. The mean age was 66 years and 83% were male. Fifty-nine percent had hypertension, 22% had diabetes, and 16% had heart failure. Ninety-seven percent of patients were on a statin and 95% were on a beta-blocker.

After propensity weighting and adjustment for relevant covariates, exposure to ACEI/ARBs reduced the risk of MACE in patients with heart failure at 1 year (hazard ratio [HR] 0.15, 95% confidence interval [CI] 0.10-0.21) and 5 years of follow-up (HR 0.36, 95% CI 0.30-0.43). In patients without a history of heart failure, ACEI/ARBs also lowered the risk of MACE at 1 and 5 years (HR 0.40, 95% CI 0.31-0.51 and HR 0.68, 95% CI 0.60-0.77, respectively).

Conclusion: In this population-based observational study, use of ACEI/ARBs reduced the risk of MACE in a cohort of post-CABG surgery patients irrespective of heart failure status. These results support the use of ACEI/ARBs as routine preventive therapy in patients who undergo CABG surgery.