Aristeidis H. Katsanos, MD, PhD
In the perpetual search for potential biomarkers that could be used for ischemic stroke diagnosis and etiological classification, the authors tested the hypothesis that early positive troponin elevation after ischemic stroke may be independently associated with the presence of a cardiac embolic source.
Using data from a prospective ischemic stroke database during a 22-month period, they identified intermediate (0-0.06 ng/mL) and positive (≥0.1 ng/mL) troponin levels in 25.1% and 11.9% of the total 1129 acute ischemic stroke patients having available troponin levels on admission. Troponin-positive patients were found to present with more severe strokes, were more likely to undergo mechanical thrombectomy, but were less likely to have favorable functional outcomes at 90 days.
In multivariable models adjusted for clinical, imaging and echocardiographic parameters, positive troponin levels (≥0.1 ng/mL) were independently associated to both cardioembolic strokes and embolic strokes of unknown source (ESUS), with high specificity (95%) but low sensitivity (<20%). Interestingly, in the current study, no association between stroke severity on admission and troponin elevation was found. Moreover, the association between troponin positivity and cardioembolic stroke subtypes persisted even after adjusting for insular infarct location, suggesting that elevated troponin after acute ischemic stroke is not only associated with catecholamine release, but might also be associated with direct myocardial injury from clot mitigation.
In conclusion, the identification of elevated troponin levels early after acute ischemic stroke should initiate a comprehensive cardiovascular evaluation in search of obvious or occult cardioembolic sources. Future studies are needed to assess the optimal timing of troponin measurement after acute ischemic stroke onset, while further defining diagnostic protocols and secondary prevention strategies that could apply to this particular patient subgroup.