Evaluation of Preventive Cardiovascular Pharmacotherapy after Coronary Artery Bypass Graft Surgery

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 1year 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 1year after CABG surgery. Measurements and Main Results Utilization rates of aspirin, beta-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, beta-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 1year after CABG surgery were evaluated by using community pharmacy and electronic health records. The proportion of patients receiving all four classes of medications at 1year was 48%. Individual utilization rates for aspirin, beta-blockers, statins, and ACEIs/ARBs were 95%, 84%, 84%, and 65%, respectively. Medication adherence, assessed by the medication possession ratio, for beta-blockers, statins, and angiotensin-modulating agents at 1year 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 1year 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, beta-blockers, and statins both at discharge and 1year 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.