Abstract WP382: Cardiac Troponin Assessment in Acute Ischemic Stroke Patients Presenting Within 4.5 Hours From Last Known Well

Abstract

Introduction: American Heart Association guidelines recommend obtaining baseline troponin in all acute ischemic stroke (AIS) patients to detect an acute coronary syndrome (ACS). Yet, data regarding the prevalence and diagnostic yield of troponin elevation in patients presenting within the time window for thrombolysis is limited. We sought to determine the diagnostic yield of cTnI in detecting ACS when assessed before or after 4.5h from last known well (LKW). Methods: We retrospectively analyzed 526 consecutive patients admitted for AIS or transient ischemic attack, who presented within 4.5h and had cardiac troponin I (cTnI) obtained within 48h from LKW. Results: The median time from LKW to cTnI measurement was 3.8h (IQR 1.5h-7.9h). 58% patients (n=306) had cTnI obtained ≤ 4.5h from LKW. After adjustment, factors independently relating to an elevated cTnI were the time to cTnI assessment (p<0.001), patient age (p=0.012), history of congestive heart failure (p<0.001), and a history of stroke/TIA (p=0.049). Patients who had a cTnI obtained within 4.5 hours from LKW, had significantly more often a normal (≤0.04 ng/mL) than elevated (>0.04 ng/mL) cTnI levels (61.9% vs. 44.7%; p=0.001). The sensitivity, specificity, and overall accuracy of an elevated cTnI assessed within 48h from LKW for ACS was 63.6%, 80.2%, and 79.5%, respectively. After stratification by the time to cTnI assessment within 4.5 h versus beyond 4.5h, the sensitivity of an elevated cTnI for ACS was markedly reduced to 42.9% whereas the specificity remained high at 84%. The optimal threshold to assess cTnI for detecting an ACS was 320 min in all included patients (sensitivity = 0.54, specificity = 0.67, Youden’s J = 0.203) and 340 minutes in patients with ACS (sensitivity 0.79, specificity 0.88, Youden’s J 0.661). Conclusions: Among patients presenting within the time window for rtPA treatment, the sensitivity of cTnI obtained within 4.5 hours from LKW to detect ACS is low. Our data suggests that cTnI routine assessment of cTnI in AIS subjects without cardiac symptoms should not be done within the first 6 hours from LKW.