MINOCA: better than obstructive myocardial infarction, but not harmless — long-term outcomes from a Southern European registry

Introduction Some studies showed that the prognosis for patients with Myocardial Infarction (MI) with Non-Obstructive Coronary Artery Disease (MINOCA) is more favourable compared to those with Obstructive Coronary Artery Disease (CAD). However, it has been proven to be worse than the general population. Objective Evaluate the prognostic value of the MINOCA compared to MI with obstructive CAD in a Southern European population. Methods A prospective, single-centre, observational cohort study was performed from January 2000 to December 2023. A total of 1,633 patients with MI were admitted and underwent coronary angiography, being followed for a mean of 7.6±6.7 years. Angiography was evaluated by two interventional cardiologists, who classified it according to the Leaman Score (which quantifies the total burden of CAD based on plaque location, type, and degree of stenosis). A score of zero was established to define MINOCA. Demographic, traditional risk factors and biochemical data were obtained from all patients. Patients with MINOCA were compared to those with obstructive coronary arteries. The primary outcome was the occurrence of cardiovascular events (CVEs) from all causes (MI, revascularisation, heart failure, stroke, peripheral arterial disease, and death). Cox regression analysis identified variables independently associated with CVEs and estimated risk in these populations. Kaplan-Meier assessed event-free survival over time. Results Of 1,633 patients with MI, only 87 patients (5.3%) had MINOCA, and 1,546 (94.7%) had obstructive CAD. Within MINOCA, 16.1% had CVEs, and 42.2% had CVEs in those with obstructive CAD. The Kaplan-Meier analysis showed that MINOCA patients had a higher event-free probability throughout follow-up. Specifically, at 10 years, the event-free rate was 79.6% vs 40.3% in the MI with obstructive CAD. After Cox regression analysis, the risk of CVEs for patients with MI with obstructive CAD was three times higher than that of those with MINOCA (HR=3.2; 95% CI: 1.9-5.4; p<0.0001). The other variables independently associated with CVEs were diabetes (p=0.041) and physical inactivity (p=0.005). Conclusion Although MINOCA patients show a significantly better prognosis than those with obstructive MI, the condition is not benign. The broader MINOCA spectrum remains associated with recurrent symptoms, frequent healthcare use, and a long-term risk profile that, while lower than obstructive CAD, progressively converges over time.