Preventive Therapy for ST-Elevation MI Underused
CHICAGO—Evidence-based cardiovascular preventive medications are underused in patients presenting with ST-elevation myocardial infarction (STEMI), investigators reported at the American Heart Association Scientific Sessions.
Michael D. Miedema, MD, a cardiology fellow at the University of Minnesota and the Minneapolis Heart Institute Foundation at Abbott Northwestern Hospital in Minneapolis, and associates examined the frequency of use of evidence-based preventive therapy in patients presenting with STEMI.
Results revealed that despite a high prevalence of cardiac risk factors, patients without known coronary artery disease (CAD) presenting with STEMI were rarely on appropriate primary prevention medications. The use of secondary prevention medication in patients with known CAD also was significantly lower than expected.
ST-elevation MI is one of the most devastating manifestations of atherosclerotic cardiovascular disease. The incidence of STEMI is decreasing, a trend due in part to increased use of primary and secondary preventive medications (in particular, anti-platelet and statin medications). Nonetheless, more than 400,000 STEMIs still occur in the United States each year.
However, while aspirin, statins, and ACE inhibitors have all been shown to provide benefit when used for both primary and secondary prevention of CAD, many patients are not on an appropriate cardiovascular preventive regimen.
For their analysis, the researchers reviewed data from 1,395 consecutive patients with documented STEMI who were enrolled in the Minneapolis Heart Institute Level 1 MI Program, a regional transfer system using a standardized protocol designed to improve time to treatment and clinical outcomes in STEMI patients. With the program, preadmission medications in patients admitted with STEMI are recorded using each patient's electronic medical record.
The analysis included 963 patients with no history of CAD prior to STEMI and 432 patients with previously diagnosed CAD prior to STEMI. Cardiovascular risk factors were prevalent in both patients with and without known CAD. In patients without known CAD, more than half had a history of tobacco abuse, half had hypertension, and almost half had hyperlipidemia.
Despite the high prevalence of risk factors, the study found that in the setting of primary prevention, only 22.2% of patients were on aspirin, 16.8% were on a statin, and 14.8% were on ACE inhibitors and/or angiotensin receptor blockers (ARBs). Only 7.8% of patients were on both an aspirin and statin and 2.1% of patients were on an aspirin, statin, and ACE inhibitor/ARB combined.
Preadmission medications in STEMI patients with known CAD were more commonly used but still suboptimal with aspirin used in 71.1% of patients, statin in 61.8%, beta blockers in 61.6%, ACE inhibitors/ARBs in 42.8%, and all treatments in 22.5%.
Possible reasons for the inadequate use of evidence-based preventive cardiovascular medications include a lack of appropriate screening, lack of indications for treatment by current guidelines, the complexity of current guidelines, inadequate risk factor stratification by current methods of risk factor assessment, and non-adherence due to cost or side effects, Dr. Miedema said. “The main problem appears not to be an issue with efficacy but rather implementation,” he said.