Prevalence and outcomes of non-ST-segment elevation myocardial infarction resulting from stent thrombosis

Stent thrombosis is an infrequent yet one of the most feared complications after stent implantation. Stent thrombosis most commonly manifests as ST-segment elevation myocardial infarction, thus the data regarding non-ST-segment elevation myocardial infarction (NSTEMI) resulting from stent thrombosis are still sparse. The aim of the study is to evaluate the prevalence and outcomes of NSTEMI resulting from stent thrombosis.

We performed a retrospective analysis of 378 consecutive NSTEMI patients who underwent coronary angiography. Patients were divided into those with and without stent thrombosis. The primary outcome was in-hospital mortality. Secondary outcome was the incidence of large myocardial infarction defined as a peak troponin I value greater than 90th percentile of the entire study population (26.5 μg/L).

Among 378 patients with NSTEMI, 12 (3.2%) patients had angiographically confirmed definite stent thrombosis. With respect to the timing of stent thrombosis, 2 patients had early, 3 had late and 7 had very-late stent thrombosis. Patients with stent thrombosis had a higher incidence of large myocardial infarction (33% vs. 9%, p = 0.02) and a higher albeit statistically insignificant peak troponin value (interquartile, 4.62 [0.19-64.0] μg/L vs. 1.21 [0.14-7.12] μg/L, p = 0.25) compared to those without stent thrombosis. There was no significant difference in in-hospital mortality between the two groups (8% vs. 2%, p = 0.2).

Stent thrombosis accounted for 3.2% cases of NSTEMI in our cohort of patients and patients with NSTEMI resulting from stent thrombosis had a higher incidence of large myocardial infarction.