Background: Elevated cardiac troponin is a marker of cardiac disease and has been recently shown to be associated with embolic stroke risk in the general population. In the acute stroke setting, we hypothesize that elevated troponin levels are more prevalent in patients with embolic stroke subtypes [cardioembolic (CE) and embolic stroke of unknown source (ESUS)] as opposed to known non cardioembolic subtypes (NE) (large vessel disease, small vessel disease, and other).
Methods: We abstracted data from our prospective stroke database and included all patients with ischemic stroke over a 22 month period. We defined positive troponin as ≥ 0.1 ng/mL. Patients diagnosed with acute myocardial infarction were excluded (n = 3).We compared clinical, laboratory and echocardiographic findings, and stroke subtypes using ESUS criteria between the two groups: Troponin+ and Troponin-.
Results: We identified 1231 patients; 1129 had troponin levels available and 10.0% (113/1129) were trop+. On univariate analyses, Troponin+ patients were more likely to be older (77.4 ± 12.6 vs. 70.8 ± 15.0, p<0.001), have hypertension (85.8% vs. 74.2%, p=0.003), coronary heart disease (31.3% vs. 20.1%, p=0.003), congestive heart failure (20.9% vs. 9.5%,p<0.001), smoking (42.5% vs. 26.4%, p<0.001), and atrial fibrillation (42.5% vs. 26.4%, p<0.001), higher admission NIHSS (14 vs. 6, p<0.001), eGFR < 60 (53.7% vs. 33.4%), larger left atrial diameter (40.9 ± 8.8 vs.37.1 ± 7.6, P<0.001), lower ejection fraction (60 vs. 65, p<0.001), and wall motion abnormalities (26.1% vs. 11.5%, p<0.001) compared troponin- patients. When compared to NE subtype, troponin+ patients were more likely to have CE (79.0% vs. 52.4%, p<0.001) and ESUS (75.0% vs. 58.9%, p=0.001) subtypes. In multivariable models, factors associated with troponin+ are NIHSS (adjusted OR per 1 unit increase1.05, 95% 1.02-1.08; p<0.001), eGFR < 60 (adjusted OR 2.41 95% CI 1.40-4.13; p=0.001), CE subtype (adjusted OR 3.37 95% CI 1.35-8.43,p=0.009), and ESUS subtype (adjusted OR 2.77 95% CI 1.15-6.66,p=0.023).
Conclusion: Elevated troponin levels in ischemic stroke is independently associated with a cardiac embolic source. Studies are needed to test anticoagulation vs. antiplatelet in patients with ESUS and elevated troponin.