Abstract 2706: Patients with the Malignant Profile Within 3 Hours of Symptom Onset have Very Poor Outcomes Following IV tPA Therapy

Abstract

Background: The “Malignant profile” is an MRI pattern that is associated with poor outcomes (mRS 5-6) following reperfusion in the 3-6 hr time window. The aim of this study was to estimate the incidence and prognostic implications of the Malignant profile, as identified by CT perfusion (CTP), in patients treated with tPA <3 hrs from stroke onset. Methods: Consecutive patients treated with iv tPA at the Stanford Stroke Center from May 2009 to May 2011 who had CTP performed prior to tPA therapy, and within 3 hrs of symptom onset, were included. Perfusion data were acquired in cine mode on 16 and 64-row CT scanners; 2 separate scans were done yielding either 4 cm or 8 cm coverage depending on the scanner type. The incidence of the Malignant profile, based on the previously published definition of a Tmax >8 sec perfusion lesion > 85 mL, was assessed using a fully automated software program (RAPID). This program also estimates the infarct core based on cerebral blood flow (rCBF) and cerebral blood volume (rCBV) thresholds <30% of the contralateral hemisphere. Poor outcome was defined as a mRS of 5-6 at 30 days. A receiver operating characteristic (ROC) curve analysis was done to identify Tmax and core volume thresholds that optimally define the Malignant profile (high specificity for poor outcome). Results: 121 patients were treated with iv tPA. Of these, 42 patients had an interpretable CTP performed within 3 hrs of symptom onset. Mean age was 75±14 years and median (IQR) NIHSS was 13 (6-19). Five patients (11%) met the pre-specified criteria for the Malignant profile and all 5 died during the acute hospitalization. ROC analysis determined that the optimized criteria were either a PWI Tmax >8 sec lesion >86 mL or an infarct core >53 mL (both criteria had 100% specificity and 56% and 67% sensitivity respectively). The optimized criteria identified 6 patients as Malignant (14%). The poor outcome rate in these patients was 100% vs. 8.3% in the 36 patients non-malignant patients (p<0.001). Conclusion: The incidence of the Malignant Profile is about 10-15% in tPA eligible patients imaged within 3 hrs of symptoms onset. The clinical outcome of these patients is very poor despite iv tPA therapy. This finding is consistent with data from patients treated with iv tPA in the 3-6 hr window. Further study is warranted to verify if CTP can reliably identify a subgroup of patients who do not benefit from iv tPA within 3 hours.