ST-elevation myocardial infarction with nonobstructive coronary arteries associated with significant mortality

1. Patients with ST-elevation myocardial infarction (STEMI) with nonobstructive coronary arteries (MINOCA) and MINOCA-mimicking disease demonstrated significantly higher five-year mortality compared to those with traditional obstructive disease underlying MI.

2. Those with STEMI secondary to MINOCA and MINOCA mimickers were also discharged with fewer cardiac medications, and underlying disease was less often diagnosed in these groups.

Evidence Rating Level: 2 (Good)        

Study Rundown: While myocardial infarction with nonobstructive arteries (MINOCA) has historically been considered low-risk in comparison to STEMI secondary to obstructive disease, there remains some ambiguity in quantifying the relative mortality risk for MINOCA patients (with either coronary artery plaque disruption, epicardial coronary spasm, or coronary embolism/thrombosis) and MINOCA mimickers (takotsubo cardiomyopathy, myocarditis, and nonischemic cardiomyopathy) compared to those with obstructive disease. Researchers investigated the clinical characteristics, presentations, and prognosis of patients with ST-segment elevation myocardial infarction, comparing those with obstructive disease, MINOCA, and MINOCA mimickers. This retrospective analysis analyzed thousands of STEMIs across three Midwestern STEMI programs. Overall, this study found that at five-year follow-up, those patients who presented with MINOCA or MINOCA mimickers were at significantly higher risk of mortality than those diagnosed with obstructive disease. In addition, patients with MINOCA or MINOCA mimickers were less likely to receive cardiac medications at discharge than their counterparts with obstructive disease, indicating that the appropriate recognition and treatment of nonobstructive disease could have impacts for patient mortality.

Click to read the study in JAMA Network Open

Relevant Reading: Long-term prognosis of patients presenting with ST-segment elevation myocardial infarction with no significant coronary artery disease (from the HORIZONS-AMI trial)

In-Depth [retrospective cohort]: In patients with STEMI, obstructive disease is often a root cause. However, those with STEMIs with nonobstructive coronaries (MINOCA) and MINOCA mimickers (myocarditis, nonischemic cardiomyopathy, takotsubo cardiomyopathy) present their own challenges in identification, treatment, and rates of morbidity and mortality. It remains unclear whether STEMI with obstructive disease presents higher mortality risk than MINOCA and MINOCA mimickers. This registry-based cohort study investigated the risk for major cardiac events and all-cause mortality following STEMI with obstructive disease compared to STEMI secondary to MINOCA and MINOCA mimickers. This is the first study that clearly distinguishes MINOCA and MINOCA mimickers. Major adverse cardiovascular events (MACEs) were analyzed at 1-year, and all-cause mortality was collected at one and five-year follow-up.A total of 8560 patients (M [SD] = 62 [14] years, 70% male) with STEMI were included from three Midwestern centers in the U.S. Approximately 95% of patients were identified as having STEMI with obstructive disease, 1.4% were patients with MINOCA, and 3.8% of patients were MINOCA mimickers. Data collected included demographic clinical data, angiography, laboratory markers, and discharge medications prescribed at discharge. Where possible, cardiac magnetic resonance imaging (CMRI) data was collected. Not only were MINOCA cases less frequently discharged with aspirin, statins, beta-blockers, angiotensin receptor blockers (ARB), angiotensin-converting enzyme inhibitors (ACEi), and P2Y12 inhibitor antiplatelets, but five-year mortality hazard risk was 1.93 times that of patients with obstructive disease (95% CI, 1.06-3.53). MINOCA mimickers were similarly discharged less often with the above medications but were at similar risk for five-year mortality compared to obstructive disease counterparts (HR 1.08, 95% CI, 0.79-1.49). However, a secondary matched cohort analysis found that mimickers, compared to those with obstructive disease, had higher five-year mortality (χ21 = 5.8; P = .02). In a comparison of STEMI with MINOCA versus MINOCA mimickers, mimickers were less often discharged with aspirin, antiplatelet therapy, and statins (p < .05). However, no difference in ACEi or ARB prescribing was noted. MINOCA mimickers were at similar risk for five-year mortality with MINOCA patients (HR 1.65, 95% CI 0.68-4.01). At the only site where CMRI was routinely implemented, patients with MINOCA were diagnosed appropriately with the underlying disease (76% of patients), compared to proper underlying diagnosis at the two other sites (42% and 57% appropriately diagnosed). This study demonstrates the importance of differentiating MINOCA etiologies from one another in order to properly identify, diagnose, and treat these conditions as they present with increased risk of mortality compared to those with obstructive disease.

Image: PD

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