Evaluation of preventive cardiovascular pharmacotherapy after coronary artery bypass graft surgery

Abstract

Study objective: To determine the rate of secondary prevention cardiovascular drug utilization in a cohort of patients who underwent coronary artery bypass graft (CABG) surgery—including specific drugs and their dosages, drug adherence, and assessment of targeted therapy--from admission to 1 year after CABG surgery.

Design: Retrospective analysis.

Setting: Cardiovascular quaternary care medical center in Edmonton, Canada.

Patients: The entire cohort consisted of 1031 adults who underwent CABG surgery between January 2009 and March 2010; a randomly selected subset of 151 patients was used to evaluate medication use and target-directed therapy at 1 year after CABG surgery.

Measurements and main results: Utilization rates of aspirin, β-blockers, statins, and angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers (ACEIs/ARBs) on admission and at discharge were determined for the entire cohort by using data from a large clinical patient registry. The proportion of patients discharged receiving all four classes of medications was 35%. Individual utilization rates for aspirin, β-blockers, and statins were 96%, 94%, and 95%, respectively; use of ACEIs/ARBs was lowest at 42%. In the 1-year post-CABG surgery substudy, medication use and target-directed therapy at 1 year after CABG surgery were evaluated by using community pharmacy and electronic health records. The proportion of patients receiving all four classes of medications at 1 year was 48%. Individual utilization rates for aspirin, β-blockers, statins, and ACEIs/ARBs were 95%, 84%, 84%, and 65%, respectively. Medication adherence, assessed by the medication possession ratio, for β-blockers, statins, and angiotensin-modulating agents at 1 year exceeded 0.85, thereby demonstrating high adherence. Evaluation of target-directed treatment of dyslipidemia and diabetes mellitus demonstrated suboptimal control, with only 66% and 54% of patients, respectively, achieving the recommended therapeutic targets.

Conclusion: The utilization rate for patients receiving all four classes of secondary prevention cardiovascular medications was 35% at discharge and 48% at 1 year after CABG surgery. These rates were primarily limited by the low utilization of angiotensin-modulating agents, although their rate improved by 22% from discharge. Utilization rates, however, were high for aspirin, β-blockers, and statins both at discharge and 1 year after surgery. Opportunities remain to further optimize secondary prevention cardiovascular pharmacotherapy in patients who undergo CABG surgery, either while in the hospital or immediately subsequent to discharge.