Optimal medical therapy for secondary prevention after an acute coronary syndrome: 18-month follow-up results at a tertiary teaching hospital in South Korea

Background: Acute coronary syndrome (ACS) is a fatal cardiovascular disease caused by atherosclerotic plaque erosion or rupture and formation of coronary thrombus. The latest guidelines for ACS recommend the combined drug regimen, comprising aspirin, P2Y12 inhibitor, angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker, β-blocker, and statin, at discharge after ACS treatment to reduce recurrent ischemic cardiovascular events. This study aimed to examine prescription patterns of secondary prevention drugs in Korean patients with ACS after hospital discharge, to access the appropriateness of secondary prevention drug therapy for ACS, and to evaluate whether to persistently use discharge medications for 18 months.

Methods: This study was retrospectively conducted with the patients who were discharged from the tertiary hospital, located in South Korea, after ACS treatment between September 2009 and August 2013. Data were collected through electronic medical record.

Results: Among 3,676 patients during the study period, 494 were selected based on inclusion and exclusion criteria. The regimen of aspirin + clopidogrel + β-blocker + angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker + statin was prescribed to 374 (75.71%) patients with ACS at discharge. Specifically, this regimen was used in 177 (69.69%) unstable angina patients, 44 (70.97%) non-ST-segment elevation myocardial infarction patients, and 153 (85.96%) ST-segment elevation myocardial infarction patients. Compared with the number of ACS patients with all five guideline-recommended drugs at discharge, the number of ACS patients using them 12 (n=169, 34.21%) and 18 (n=105, 21.26%) months after discharge tended to be gradually decreased.

Conclusion: The majority of ACS patients in this study received all five guideline-recommended medications at discharge from the hospital. However, the frequency of using all of them had been gradually decreased 3, 6, 12, and 18 months after discharge compared with that at discharge. Careful monitoring of adherence on ACS secondary prevention medications may help improve the outcomes of ACS patients in terms of recurrent ischemic cardiovascular events.