Background: Although some previous studies assessed characteristics and outcome of patients with suspected no-ST-segment elevation acute myocardial infarction (NSTEMI), but no obstructive coronary artery disease (NOCAD) at angiography, most were performed before high-sensitivity troponin assays were available.
Methods and results: We reviewed data of patients admitted to our hospital with a suspicion of NSTEMI between 2013 and 2016. Patients with previous evidence of CAD (except those with fully percutaneous coronary revascularization) were excluded. Patients were divided into those with obstructive CAD and those with NOCAD (no coronary stenosis ≥50% in any vessel). The final population included 430 patients - 317 (73.7%) with CAD and 113 (26.3%) with NOCAD. Compared with CAD, NOCAD patients were younger, more frequently women, and had a lower prevalence of cardiovascular risk factors and peak troponin level. In-hospital death or myocardial infarction occurred in eight (2.5%) and two (1.8%) patients in CAD and NOCAD patients, respectively (P = 1.00). A lower left ventricular ejection fraction (LVEF) and left main CAD were the only independent predictors of in-hospital death and death or myocardial infarction.
Conclusions: Among patients with suspect NSTEMI, about one-fourth showed NOCAD at angiography in the era of elevated sensitivity troponin assays and when excluding patients with largely predictable obstructive CAD. Higher troponin levels were associated with obstructive CAD, but a lower LVEF and left main disease only predicted in-hospital outcome in this population.