(CCSP014) FOLLOW-UP DOSING OF GUIDELINE-INDICATED MEDICATIONS AFTER MYOCARDIAL INFARCTION: INSIGHTS FROM THE AMIQA CANADA PROSPECTIVE COHORT STUDY

Background: Achieving the target doses of indicated medications after myocardial infarction (MI) is associated with improved outcomes and is a marker of the quality of care. We studied the use and follow-up dosing of core cardiac medications among patients with MI complicated by depressed left ventricular ejection fraction (LVEF). Our objective was to determine whether adherence to evidence-based medication dosing is associated with receipt of follow-up LVEF imaging or progression of LVEF within 6 months of follow-up.

METHODS AND RESULTS: The AMIQA Canada study enrolled 501 patients (mean age 63, 22.6% female) with acute MI and LVEF ≤45%, from 14 Canadian centres. Patients were followed for 6 months to determine adherence to post-MI follow-up recommendations. We assessed use and dosing of beta-blockers, ACE-inhibitors, ARBs, mineralocorticoid receptor antagonists (MRA), and statins, and compared changes in LVEF among those taking ≥50% vs. < 50% of target dose in follow-up.

At 6 months, mean percent target dose was ≤50% for beta-blockers, ACE-inhibitors, and ARBs, but was 72.3% for MRAs (among 24% receiving the medication) while 86.8% were taking a high-intensity statin. Only use of MRAs was associated with follow-up LVEF reassessment (p < 0.001). Receiving ≥50% of target dose was not associated with changes in LVEF.

Conclusion: Except for statins, most patients were not receiving target doses of indicated medications after MI with reduced LVEF. Follow-up dosing was not associated with LVEF reassessment or improvement in LVEF. Future quality improvement initiatives may require distinct strategies for improving adherence to recommendations for medication dosing versus follow-up imaging.