Abstract 2433: Outcomes Of Thrombolysis In The 0-4.5 Hour Time Window In Acute Stroke Patients Selected Using Ct Perfusion Imaging

Background: Thrombolytic treatment within 4.5 hours of symptom onset is effective in preventing death or significant disability in 1 out of 7 stroke patients, but with a 5% risk of symptomatic intracerebral haemorrhage (sICH). We hypothesised that patient selection using CT perfusion (CTP) imaging can increase the benefit of thrombolysis and reduce the risk of sICH. Methods: We extracted data from a prospective thrombolysis database of 533 consecutive stroke patients of all ages thrombolysed with 4.5 hours of symptom onset. Thrombolysis decisions were made on the basis of a non-enhanced CT (NECT) scan but CTP was undertaken in a proportion of patients, depending upon physician decisions. In the analysis, patients with an Alberta Stroke Program Early CT Score (ASPECTS) of ≥7 on NECT and an estimated volumetric perfusion mismatch of ≥100% on PCT were defined as optimal candidates for thrombolysis. Imaging was reviewed by 2 raters masked to outcomes. Nine patients were excluded from analysis because of poor PCT quality. Findings: Of the 524 patients included, 97 patients had CTP mismatch that met the defined criteria for mismatch guided thrombolysis. Their age (72 v 70 years), sex (50% v 54% male), pre-morbid modified Rankin Scale (mRS) score, baseline National Institute of Health Stroke Scale (NIHSS) score (13.6 v 12.6,p=0.20), blood glucose (6.8 v 6.6 mmols) and blood pressure (149/84 v 148/79 mm Hg) were comparable with those thrombolysed on the basis of NECT imaging. At 3 months, the proportion of patients with modified Rankin Score of 0-1 and 0-2 was higher in those with mismatch (36% v 29%, p=0.003 and 51% v 42%, p=0.007 respectively) and there was a non-statistical trend towards reductions in any ICH (13% v 16%), sICH (1.1% v 2.8%) and mortality (23% v 18%). CTP mismatch was an independent determinant of a favourable outcome at 3 months in regression analyses to adjust for covariates. Conclusions: Patient selection based on estimation of salvageable brain tissue using CTP mismatch may improve functional outcomes at 3 months. The value of CT perfusion in increasing the effectiveness and safety of thrombolysis within established therapeutic time windows merits investigation.