The aim of the study was to assess the frequency and predictive factors of microvascular obstruction (MVO) in patients with non-ST-segment elevation myocardial infarction (NSTEMI). This study included 190 consecutive patients with NSTEMI who underwent percutaneous coronary intervention (PCI) within 24 h after admission and cardiac magnetic resonance (CMR) imaging, 4.1 days after angiography. MVO was defined using the CMR criteria. MVO was detected 26 of 190 patients (13.8%). Patients with MVO had higher peak high-sensitivity troponin T, creatine-kinase and creatine kinase-myocardial band levels and higher proportions of those with baseline thrombolysis in myocardial infarction (TIMI) flow grade 0-1, absence of collateral circulation, post-PCI TIMI flow grade <3, myocardial blush grade <3 and angiographic no-reflow than patients without MVO. Patients with MVO had larger initial area at risk [median (25th-75th percentiles), 23.9% (17.4-33.9%) vs. 16.1% (7.8-27.7%), P = 0.018] and infarct size [11.4% (6.6-19.2%) vs. 1.4% (0-4.7%) of the left ventricle, P < 0.001] than patients without MVO. In multivariable analysis, the culprit lesion localization in the circumflex coronary artery [adjusted odds ratio (OR) 13.71, 95% confidence interval 2.91-64.58, P < 0.001] and the infarct size [adjusted OR 3.37 (1.80-6.29), P < 0.001, for each 5% of the left ventricle] were independently associated with the increased risk for MVO. In patients with NSTEMI undergoing early PCI, the MVO defined by CMR imaging was present in 13.8 % of the patients. The localization of culprit lesion in the circumflex coronary artery and larger infarct size were independently associated with the increased risk for MVO.
I. Medizinische Klinik und Poliklinik (Kardiologie); Institut für Radiologie; Klinik für Herz- und Kreislauferkrankungen im Erwachsenenalter (Prof. Schunkert)