Long-term Prognosis of Patients With Non-ST-segment Elevation Acute Myocardial Infarction and Coronary Arteries Without Significant Stenosis.

INTRODUCTION AND OBJECTIVES There is debate regarding the prognostic significance of the absence of significant coronary lesions in patients with non-ST-segment elevation acute myocardial infarction. We investigated long-term prognosis in a contemporary cohort of these patients. METHODS Retrospective observational study of 5203 patients with acute coronary syndrome. Propensity score matching was used to create 2 groups of 367 patients with non-ST-segment elevation acute myocardial infarction matched by the absence or presence of significant coronary lesions. In the matched cohort, we determined the impact of the absence of significant coronary lesions on mortality or readmission for acute coronary syndrome for 4.8 (2.6) years after discharge. RESULTS Mortality or readmission for acute coronary syndrome was lower among patients without significant lesions (26.4% vs 32.7%; P = .09). Mortality in both groups was 19.1%. In contrast, patients without significant lesions had a lower incidence of readmission for acute coronary syndrome (2.0/100 vs 3.9/100 person-years; P = .003). The incidence of mortality or readmission for acute coronary syndrome was similar in patients without significant lesions and those with significant 1-vessel disease (26.4% vs 27.5%; P = .19), but lower than that in patients with 2-vessel disease (37.8%; P = .007) and 3-vessel disease or left main coronary artery disease (41.1%; P = .002). CONCLUSIONS Patients with non-ST-segment elevation acute myocardial infarction and coronary arteries without significant lesions have similar long-term mortality but lower readmission rates for acute coronary syndrome than patients with significant lesions. Mortality or readmission for acute coronary syndrome is similar in patients without significant lesions and patients with 1-vessel disease, but lower than in patients with disease in 2 or more vessels.