Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Kneihsl, M.
Relevance of imaging and laboratory biomarkers for the detection of cardioembolic sources in cryptogenic stroke patients
Doktoratsstudium der Medizinischen Wissenschaft; Humanmedizin; [ Dissertation ] Medical University of Graz; 2021. pp. 95
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- Autor*innen der Med Uni Graz:
- Kneihsl Markus
- Betreuer*innen:
- Bisping Egbert Hubertus
- Enzinger Christian
- Gattringer Thomas
- Altmetrics:
- Abstract:
- Introduction: Occult atrial fibrillation (AF) is an important undetected cause of cryptogenic stroke (CS). Prolonged cardiac rhythm monitoring is the method of choice to detect silent episodes of AF, but its use is limited by costs and availability. In this context, biomarkers that could help to steer the diagnostic management of such patients would be of great advantage. In this study, we tested laboratory and neuro-/ cardiac imaging biomarkers for the prediction of occult AF in CS patients (a) in the early in-hospital phase after stroke (project 1) and (b) over long-term follow-up after hospital discharge (project 2). Methods: For the first project, all ischemic stroke patients who were admitted at the Stroke Unit of the Department of Neurology of the University Hospital Graz between April 2017 and April 2018 underwent routine diagnostic work-up. If no distinct stroke etiology was identified (CS), patients underwent a prolonged cardiac rhythm monitoring for ≥72 hours during hospital stay. Blood biomarkers (NT-proBNP, D-dimer, Antithrombin-III) were analyzed within 24 hours after Stroke Unit admission. For the second project, a risk score for the long-term prediction of AF was developed based on a literature review including clinical, laboratory and neuro-/ cardiac imaging markers that had been associated with occult AF in CS patients. To evaluate the score, over an 18-months period, all Stroke Unit patients with CS were followed after hospital discharge for a later diagnosis of occult AF. Results: In the first study, 143 CS patients were included. Of those, 14 patients were diagnosed with AF on prolonged in-hospital cardiac rhythm monitoring. The admission NT-proBNP cutoff value of ≥505 pg/ml (highest Youden’s index) correctly predicted AF in 12 of 14 patients (negative predictive value: 98%) while hypercoagulability markers were non-contributory. In the second project, 24 out of 150 CS patients (16%) were diagnosed with AF during a median follow-up period of 13 months. The predefined AF Risk Score (cutoff ≥4 points, highest Youden’s index) had a sensitivity of 79% and a specificity of 72% for the long-term prediction of occult AF in CS patients. When adding NT-proBNP above the prespecified cutoff of 505 pg/ml to the score, sensitivity increased to 87% while specificity remained at 72%. Of specific note, only one patient with an AF risk score below 4 was diagnosed with AF during the follow-up period (negative predictive value: 99%). Discussion: This study supports the value of NT-proBNP to predict AF in CS patients in the early in-hospital phase. Patients with low NT-proBNP admission levels (<505 pg/ml) are at very low risk to be diagnosed with AF early on. Moreover, we here developed an AF Risk score for the long-term prediction of AF in CS patients with high sensitivity and reasonable specificity. Low risk scores of <4 points almost excluded a later diagnosis of AF.