Randomized Pilot Trial on Optimal Treatment Strategy, Myocardial Changes, and Prognosis of Patients with Myocardial Infarction with Nonobstructive Coronary Arteries (MINOCA).

BACKGROUND: Myocardial infarction with nonobstructive coronary arteries (MINOCA) remains an unresolved challenge. Many different diagnostic approaches are often required to diagnose, confirm, and evaluate MINOCA. The prevalence can be as high as 13% of all acute myocardial infarction patients, indicating that this condition is not rare. At this time, there have been no completed randomized clinical trials involving MINOCA patients, and a better understanding of the mechanisms and management of these patients is important. This exploratory analysis seeks to find possible etiologic factors, the value of novel biomarkers, and the effect of different treatment strategies in patients with MINOCA. METHODS: This prospective randomized pilot trial will include 150 patients with MINOCA. A thorough clinical, laboratory, and imaging evaluation will be performed, including novel biomarkers and modern imaging techniques (heart magnetic resonance imaging and noninvasive testing). The duration of the enrollment is 18 months, and duration of the follow-up is 12 months from the enrollment of the first patient. RESULTS: The trial is registered under www.clinicaltrials.gov: NCT04538924. The study is currently recruiting participants. CONCLUSIONS: Because MINOCA is not a benign disease, the results of the current investigation could inform future diagnostic and therapeutic strategies and enhance the understanding of MINOCA patients.

Antiplatelet therapy in patients with myocardial infarction without obstructive coronary artery disease.

OBJECTIVE: Approximately 10% of patients with myocardial infarction (MI) have no obstructive coronary artery disease. The prognosis and role of intensified antiplatelet therapy in those patients were evaluated. METHODS: We analysed data from the Clopidogrel and Aspirin Optimal Dose Usage to Reduce Recurrent Events-Seventh Organisation to Assess Strategies in Ischaemic Symptoms trial randomising patients with ACS referred for early intervention to receive either double-dose (600 mg, day 1; 150 mg, days 2-7; then 75 mg/day) or standard-dose (300 mg, day 1; then 75 mg/day) clopidogrel. Outcomes in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) versus those with obstructive coronary artery disease (CAD) and their relation to standard-dose versus double-dose clopidogrel were evaluated. The primary outcome was cardiovascular (CV) death, MI or stroke at 30 days. RESULTS: We included 23 783 patients with MI and 1599 (6.7%) with MINOCA. Patients with MINOCA were younger, presented more frequently with non-ST-segment elevation MI and had fewer comorbidities. All-cause mortality (0.6% vs 2.3%, p=0.005), CV mortality (0.6% vs 2.2%, p=0.006), repeat MI (0.5% vs 2.3%, p=0.001) and major bleeding (0.6% vs 2.4%, p<0.0001) were lower among patients with MINOCA than among those with obstructive CAD. Among patients with MINOCA, 2.1% of patients in the double-dose clopidogrel group and 0.6% in the standard-dose group experienced a primary outcome (HR 3.57, 95% CI 1.31 to 9.76), whereas in those with obstructive CAD, rates were 4.3% and 4.7%, respectively (HR 0.91, 95% CI 0.80 to 1.03; p value for interaction=0.011). CONCLUSIONS: Patients with MINOCA are at lower risk of recurrent CV events compared with patients with MI with obstructive CAD. Compared with a standard clopidogrel-based dual antiplatelet therapy (DAPT) regimen, an intensified dosing strategy appears to offer no additional benefit with a signal of possible harm. Further randomised trials evaluating the effects of potent DAPT in patients with MINOCA are warranted. TRIAL REGISTRATION NUMBER: NCT00335452.