The role of a comprehensive two-step diagnostic evaluation to unravel the pathophysiology of MINOCA: A review.

The role of cardiac magnetic resonance (CMR) in identifying mechanisms for myocardial infarction with non-obstructed coronary arteries (MINOCA) is well established. Recent reports have highlighted the potentially key role of invasive management in this diagnostic process. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) allow precise evaluation of coronary anatomy, and assessment of coronary physiology in the catheter laboratory provides information on the hemodynamic significance of sub-critical atherosclerosis and on coronary microvascular dysfunction (CMD). We reviewed the evidence for the contribution of invasive diagnostic techniques in identifying provisional causes for MINOCA. Overall, among 82 studies including 8457 patients were selected. In the acute phase, 16 studies with IVUS or OCT (1207 patients) disclosed that plaque disruption and spontaneous coronary artery dissection had a pooled prevalence of 38% (95% confidence intervals (CI): 29% to 51%) and 16% (95% CI: 9% to 27%), respectively. In 18 studies, coronary function testing (1449 patients) showed a pooled prevalence of spontaneous and/or provoked epicardial coronary spasm of ~28% (95% CI:17% to 41%). In 3 studies (456 patients), the pooled prevalence of CMD was ~32% (95% CI: 20% to 49%). In the subacute phase, 42 CMR studies (5821 patients) showed that a pooled prevalence of myocarditis, takotsubo syndrome and cardiomyopathy of 26% (95% CI: 12% to 40%), 11% (95% CI: 5% to 25%), and 7% (95% CI: 1% to 19%), respectively. In 12 studies on thrombophilia screening (n = 834), the pooled prevalence of thrombotic disorder was ~11% (95% CI: 7%% to 25%). In conclusion, the pathophysiology of MINOCA can be established in the majority of cases using both invasive and non-invasive tools to provide direction for appropriate management.