Medical Therapy for Secondary Prevention and Long-Term Outcome in Patients with Myocardial Infarction with Non-Obstructive Coronary Artery (MINOCA) Disease
Background—Myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA) occurs in 5-10% of all patients with MI. Clinical trials of secondary prevention treatment in MINOCA patients are lacking. Therefore, the aim of this study was to examine the associations between treatment with statins, renin-angiotensin system blockers, beta-blockers, dual antiplatelet therapy and long-term cardiovascular events.
Methods—Observational study of MINOCA patients recorded in the SWEDEHEART registry between July 2003 and June 2013 and followed until December 2013 for outcome events in the Swedish Cause of Death Register and National Patient Register. Out of 199,162 MI admissions, 9,466 consecutive unique patients with MINOCA were identified. Among those, the 9,136 patients surviving the first 30 days after discharge constituted the study population. Mean age was 65.3 years and 61% were women. No patient was lost to follow-up. A stratified propensity score analysis was performed to match treated and untreated groups. The association between treatment and outcome was estimated by comparing between treated and untreated using cox proportional hazards models. The exposures were treatment at discharge with statins, ACE-inhibitors/Angiotensin receptor blockers (ACEI/ARB), beta-blockers and dual antiplatelet therapy (DAPT). The primary endpoint was major adverse cardiac events (MACE) defined as all-cause mortality, hospitalization for MI, ischemic stroke and heart failure.
Results—At discharge 84.5%, 64.1%, 83.4% and 66.4% of the patients were on statins, ACEI/ARB, beta-blockers and DAPT, respectively. During the follow-up of a mean of 4.1 years, 2,183 (23.9%) patients experienced a MACE. The Hazard Ratios (95% confidence intervals) for MACE were 0.77 (0.68-0.87), 0.82 (0.73-0.93), and 0.86 (0.74-1.01) in patients on statins, ACEI/ARB and beta-blockers, respectively. For patients on DAPT followed for one year the Hazard Ratio was 0.90 (0.74-1.08).
Conclusions—The results indicate long-term beneficial effects on outcome in patients with MINOCA of treatment with statins and ACEI/ARBs, a trend toward a positive effect of beta-blocker treatment, and a neutral effect of DAPT. Properly powered randomized clinical trials to confirm these results are warranted.
- myocardial infarction
- secondary prevention
- statin therapy
- angiotensin-converting enzyme inhibitor
- dual antiplatelet therapy
- Received November 8, 2016.
- Revision received January 9, 2017.
- Accepted January 31, 2017.