Outcomes and Medical Therapy in Myocardial Infarction With Nonobstructive Coronary Arteries: A Systematic Review and Meta-Analysis.

Myocardial infarction with nonobstructive coronary arteries (MINOCAs) is a disease that has been poorly characterized with unclear clinical and therapeutic outcomes. The association of medical therapy with cardiovascular outcomes in patients with MINOCA has been inadequately assessed. The purpose of this meta-analysis is to evaluate the association of MINOCA at risk of adverse cardiovascular outcomes as compared with myocardial infarction with coronary artery disease (MICAD) and the efficacy of medical therapy in reducing the risk of adverse outcomes. A literature search was conducted for studies reporting on the association of MINOCA at risk of adverse outcomes as compared with MICAD. A literature search was also conducted for studies reporting on the association of medical therapy at risk of adverse outcomes in patients with MINOCA. A total of 29 studies with 893,134 participants met inclusion criteria comparing MINOCA to MICAD. Patients with MINOCA had a significantly lower risk of adverse outcomes as compared with MICAD. Nine studies with 27,731 MINOCA patients met inclusion criteria for evaluating the utility of medical therapy. Medical therapy did not significantly reduce risk of MACE; however, there was a trend toward lower risk in patients treated with β blockers. In conclusion, our results suggest that MINOCA is associated with a lower risk of in-hospital and long-term adverse outcomes compared with MICAD. Standard medical therapy is not associated with a lower risk of adverse cardiovascular outcomes in patients with MINOCA. Additional high-quality studies are required to evaluate the utility of specific medication classes for the treatment of specific etiologies of MINOCA.