Clinical outcome and correlates of coronary microvascular obstruction in latecomers after acute myocardial infarction

Aims: Microvascular obstruction (MVO) is associated with a worse prognosis in patients with ST-elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention (PCI). However, data about incidence, clinical outcome and correlates of MVO in latecomers after STEMI are still lacking. Methods: We prospectively enrolled consecutive patients that were latecomers after STEMI (symptoms onset >12 h) undergoing PCI. We performed an angiographic analysis to assess the occurrence of MVO [defined as TIMI flow grade <= 2 or 3 with a myocardial blush grade <2]. Moreover, we performed a clinical and echocardio-graphic follow-up to assess the occurrence of major adverse cardiovascular events (MACE), defined as the composite of cardiac death, myocardial infarction and rehospitalization for heart failure, and to evaluate left ventricle remodelling. Results: Seventy-eight patients were enrolled [mean age 67.58 +/- 11.72 years, 57 (73%) male; mean time of symptom onset 23.14 +/- 16.06 h] with a mean follow-up time of 29.7 +/- 14.1 months. MVO occurred in 39 (50%) patients. Patients with MVO had a higher rate of MACE [18 (46%) vs. 3 (8%), p < 0.001] and LV remodelling [25 (64%) vs. 6 (15%), p < 0.001] compared with patients without MVO. By multivariable Cox regression MVO and left anterior descending artery were independent predictors of MACE. Conclusions: Latecomers after STEMI have a high risk to develop MVO that is related to an adverse prognosis. Appropriate management and follow-up strategies should be implemented in such high-risk patients group. (C) 2017 Elsevier B.V. All rights reserved.