Long-term prognostic role of persistent microvascular obstruction determined by cardiac magnetic resonance for ST-segment elevation myocardial infarction

Abstract

Background: Microvascular occlusion (MVO) determined by cardiac magnetic resonance (CMR) exists both in acute phase and recovery period after myocardial infarction. This study aimed to examine the long-term prognosis predictive value of persistent MVO for ST-segment elevation myocardial infarction (STEMI).

Methods: A prospective cohort enrolled 344 patients with STEMI who received primary percutaneous coronary intervention and underwent CMR both in 5 to 7 days and 6 months after STEMI to determine if MVO had occurred. All patients were followed up for 5 years, and major adverse cardiovascular events (MACE) were recorded.

Results: This study included 344 STEMI patients with an average age of 57 years at 6 centers in China. A total of 192 (55.81%) patients with STEMI did not have MVO by CMR, and 105 (30.52%) patients showed transient MVO in acute phase of myocardial infarction and 47 (13.66%) patients showed persistent MVO at 6 months after infarction. The patients with persistent MVO had the largest infarct size and the lowest left ventricular ejection fraction both in 5 to 7 days and 6 months after infarction (all P < .001). Patients with persistent MVO showed a significantly higher incidence of 5-years MACE than those without MVO or with MVO in only 1 week (66.0% vs 18.8% and 27.6%, respectively; P < .001). Persistent MVO was an independent strong predictor of MACE after adjustment for other CMR variables (OR: 3.912, 95% CI: 1.904-8.037; P < .001). A propensity score-matched population comprised 43 patients with persistent MVO and 43 patients with transient MVO in only 1 week. The patients with persistent MVO had a higher incidence of MACE than those with transient MVO (65.1% [28/43] vs 37.2% [16/43]; P = .010).

Conclusion: Persistent MVO by CMR at the chronic phase of STEMI provides useful prognostic information regarding long-term outcomes after primary percutaneous coronary intervention.