Abstract 2223: Diagnoses and Outcomes of t-PA Treated Patients with No Imaging Evidence of Acute Ischemic Stroke

Abstract

Background/Purpose: Intravenous Alteplase (t-PA) improves outcome in patients with acute ischemic stroke. Of those who recover fully, some may not have had ischemia. We analyzed the frequency and post-treatment outcomes of patients with no imaging evidence of stroke and aimed to delineate the frequency of strokes with full recovery from that of stroke mimics treated with t-PA. Methods: We included all adult stroke patients treated with IV t-PA within 3 hours of stroke onset from the UCSD SPOTRIAS database. Group 1: Patients with neuroimaging evidence of acute stroke (IPS); Group 2: no neuroimaging evidence of acute stroke (INS). All diagnoses were established by an independent adjudicating body. We reviewed medical records, neuroimaging, and compared discharge diagnosis, 90-day mRS, and incidence of intracranial hemorrhage. We adjusted for age, admission NIHSS, and pre-stroke mRS in multivariable models. Results: We identified 61patients with IPS and 25 with INS, with similar baseline characteristics, except for baseline NIHSS (IPS 13.4±8.2, INS 8.4±5.9, p=0.007) and incidence of cardiac arrhythmias (IPS 36.1%, INS 4.0%, p=0.002). Adjusted for age and baseline NIHSS, we found no difference in outcome. ICH was found in 23% of the IPS patients and was symptomatic in 4.9%. None of the INS patients had ICH. Conclusions: Radiologic evidence of acute ischemic stroke was absent in 10.5% of the 86 patients in the UCSD SPOTRIAS database who were treated with t-PA and given a clinical diagnosis of acute ischemic stroke on adjudicating body review at discharge. The majority (64%) of imaging negative stroke patients in our study ultimately received the clinical diagnosis of acute stroke. No significant difference in outcomes (mRS) was found between imaging negative and imaging positive stroke code patients, aside from the increased ICH frequency in imaging positive patients. This lack of outcome difference emphasizes that while imaging plays an important role as a surrogate marker in determining the diagnosis, a detailed clinical evaluation is essential in the correct treatment of acute ischemic stroke. Imaging negative stroke patients are common and future larger scale prospective data is required to analyze the true frequency of stroke mimics versus imaging negative stroke.