Prognostic Value of Cardiac Magnetic Resonance Imaging in Patients With a Working Diagnosis of MINOCA—An Outcome Study With up to 10 Years of Follow-Up

Abstract

BACKGROUND: Patients with a working diagnosis of myocardial infarction with unobstructed coronary arteries (MINOCA) represent a heterogeneous cohort. The prognosis could vary substantially depending on the underlying cause. Although cardiac magnetic resonance (CMR) is considered a key diagnostic tool in these patients, there are limited data linking the CMR diagnosis with the outcome. METHODS: This study is a prospective outcomes registry of consecutive patients presenting with a working diagnosis of MINOCA who were clinically referred for CMR at an academic hospital from October 2003 to February 2020. We assessed the relationships between the prespecified CMR diagnoses of acute myocardial infarction (AMI), myocarditis, nonischemic cardiomyopathy (NICM), normal CMR study, and major adverse cardiac events (MACEs). RESULTS: Of 252 patients, the CMR diagnosis was AMI in 63 (25%), myocarditis in 33 (13%), NICM in 111 (44%), normal CMR in 37 (15%), and other diagnoses in 8 (3%). A specific nonischemic cause was diagnosed allowing true MINOCA to be ruled-out in 57% of the cohort. During up to 10 years of follow-up (1595 patient-years), MACE occurred in 84 patients (33%), which included 64 deaths (25%). The unadjusted cumulative 10-year rate of MACE was 47% in AMI, 24% in myocarditis, 50% in NICM, and 3.5% in patients with a normal CMR (Log-rank P <0.001). The CMR diagnosis provided incremental prognostic value over clinical factors including age, gender, coronary artery disease risk factors, presentation with ST-elevation, and peak troponin (incremental χ² 17.9, P <0.001); and patients with diagnoses of AMI, myocarditis, and NICM had worse MACE-free survival than patients with a normal CMR. CONCLUSIONS: In patients with a working diagnosis of MINOCA, CMR allows ruling-out true MINOCA in over half of the patients. CMR diagnoses of AMI, myocarditis, and NICM are associated with worse MACE-free survival, whereas a normal CMR study portends a benign prognosis.

Ejection Fraction-Related Differences of Baseline Characteristics and Outcomes in Troponin-Positive Patients without Obstructive Coronary Artery Disease

“…Of note, no research has demonstrated that a CMR diagnosis of myocarditis carries a worse prognosis compared to a normal CMR examination in patients with a working diagnosis of MINOCA. Similarly, previous studies have not demonstrated that the diagnosis of AMI is a predictor of mortality in multivariate analysis after accounting for conventional clinical indices (e.g., age, coronary artery disease [CAD] risk factors, troponin levels), despite the fact that patients with MINOCA with a CMR diagnosis of AMI appear to have moderately higher mortality than those with a normal CMR [8,39,40]. The underlying reason for MINOCA could have a significant impact on the prognosis.…”

“…This underscores the significance of CMR for diagnostic and prognostic reasons]. In addition, CMR diagnoses of acute myocardial infarction, myocarditis, and nonischemic cardiomyopathy are independent predictors of poor outcomes [8].…”

Gamechanger: Diagnostic and Prognostic Value of Cardiovascular Magnetic Resonance in MINOCA

“…In this issue of Circulation: Cardiovascular Imaging, Konst et al 11 investigate LGE in the setting of myocardial infarction and unobstructed coronary arteries (MINOCA). MINOCA is not rare and occurs in ≈5% of patients with acute myocardial infarction.…”