Myocardial infarction with angiographically normal coronary arteries in the contemporary era.

BACKGROUND: Myocardial infarction with angiographically normal coronary arteries (MINC) is a well recognized clinical entity, but limited data regarding outcome and prognostic factors exist in the literature. This study sought to identify clinical characteristics and etiological factors as well as outcome predictors in patients with MINC.

DESIGN: Retrospective follow-up study.

METHODS: Fifty-eight patients presenting with MINC fulfilled the study inclusion criteria. Clinical characteristics, cardiovascular risk factors, and etiologic and laboratory data were harvested and compared with those obtained from patients with myocardial infarction and single vessel coronary artery disease (MISVD). Follow-up information regarding survival and cardiac events such as angina, reinfarction and heart failure was collected and prognostic factors identified.

RESULTS: Compared with the MISVD group, MINC patients had a lower prevalence of hypercholesterolemia and ST elevation. Hypercoagulopathy, collagen tissue disorder, cocaine abuse and Takotsubo cardiomyopathy were identified etiologies in some MINC patients. During follow-up, patients with MINC were less likely to sustain reinfarction (log-rank P<0.001) and cardiovascular death (log-rank P=0.04) on Kaplan-Meier survival analysis. Recurrence of angina and heart failure were the most prevalent cardiac events in the MINC group. Cox proportional multivariate regression analysis identified left ventricular ejection fraction as an independent predictor of cardiac events in the MINC cohort.

CONCLUSION: MINC is associated with lower mortality and morbidity compared with infarction in the setting of single vessel disease. Left ventricular function is an independent predictor of poor outcome.