Background: Asymptomatic elevations in serum troponin levels often occur in patients with acute ischemic stroke. We evaluated whether patients with embolic strokes of undetermined source (ESUS) have higher rates of asymptomatic elevated troponin than patients with small- or large-vessel strokes.
Methods: The Cornell AcutE Stroke Academic Registry (CAESAR) prospectively enrolled all adults with acute stroke at Weill Cornell Medical Center from 2011 to 2014. The etiology of stroke was retrospectively ascertained by two independent neurologists, with a third resolving any disagreements. We included patients with ESUS and, as controls, those with small- or large-vessel strokes. We defined an asymptomatic troponin elevation as a value exceeding our laboratory’s upper limit (0.04 ng/mL) within 24 hours of presentation, in the absence of a clinically recognized acute myocardial infarction. We used the chi-square test to compare rates of elevated troponin in patients with ESUS versus controls. Multiple logistic regression was used to evaluate the association between ESUS and elevated troponin after adjustment for demographics, NIH Stroke Scale score, insular infarction, and vascular risk factors. In a sensitivity analysis, we excluded patients diagnosed with atrial fibrillation during ambulatory heart-rhythm monitoring.
Results: Among 547 patients, 258 (47.3%) had ESUS and 285 (52.7%) had a small- or large-vessel stroke. Patients with ESUS were younger (mean age 65.7 vs. 69.6 years) and more often female, and had equally severe strokes, higher rates of insular infarctions, and fewer vascular risk factors. In univariate analysis, patients with ESUS more often had an elevated troponin than controls (14.7% versus 8.0%; P = 0.01). After adjustment for demographics, stroke severity, insular involvement, and vascular risk factors, ESUS remained associated with elevated troponin (OR, 2.44; 95%, 1.04-5.77). This result was unchanged in our sensitivity analysis.
Conclusions: Elevations in serum troponin appear to be more common in patients with ESUS than in those with small- or large-artery strokes. Further research is required to understand the pathogenesis and significance of elevated troponin in patients with ESUS.