Non-ST-Elevation Myocardial Infarction with Non-significant Coronary Artery Disease as a Symptom of Occult or New Malignancy.

BACKGROUND: Malignancy is a known risk factor for venous thromboembolism; however, the association with arterial thromboembolic events remains unclear. OBJECTIVES: To examine the association between non-ST-elevation myocardial infarction (NSTEMI) and non-significant coronary artery disease (CAD) and the presence of new or occult malignancy. METHODS: An observational cohort, single-center study was performed 2010-2015. Adult patients with NSTEMI, who underwent coronary angiography and had no significant coronary lesion, were included. Using propensity score matching, we created a 2:1 matched control group of adults with NSTEMI, and significant coronary artery disease. Risk factors for new or occult malignancy were assessed using multivariate backward stepwise logistic regression analysis. The primary outcome was new or occult malignancy, defined as any malignancy diagnosed in the 3 months prior and 6 months following the myocardial infarction (MI). RESULTS: During the study period, 174 patients who presented with MI with non-obstructive coronary arteries were identified. The matched control group included 348 patients. There was no significant difference in the group demographics, past medical history, or clinical presentation. The incidence of new or occult malignancy in the study group was significantly higher (7/174, 4% vs. 3/348, 0.9%, P = 0.019). NSTEMI with non-significant CAD was an independent risk factor for occult malignancy (odds ratio [OR] 4.6, 95% confidence interval [95%CI] 1.1-18.7). Other risk factors included active smoking (OR 11.2, 95%CI 2.5-49.1) and age (OR 1.1, 95%CI 1.03-1.17). CONCLUSIONS: NSTEMI with non-significant CAD may be a presenting or early marker of malignancy and warrants further investigation.