Abstract TP41: Perfusion CT Identifies Ischemic Stroke Patients With a Good Natural History Regardless of Treatment

Abstract

Introduction: There remains uncertainty about the benefits of reperfusion therapy in minor stroke. In this study we tested the hypothesis that patients with a small perfusion lesions do not show clinical benefit from reperfusion therapy when using conventional outcome scores such as the modified Rankin scale. Methods: A prospective cohort of consecutive ischemic stroke patients who fulfilled standard clinical/NCCT eligibility criteria with additional perfusion and angiography CT before treatment with iv alteplase were collected. Volumetric CT perfusion was retrospectively analysed to identify patients with a small perfusion lesion (defined as a delay time lesion 3 seconds <15mL). The primary analysis compared 3-month mRS as well as acute and 24 hour NIHSS scores in patients with a small perfusion lesion who were treated with rtPA against those who were not using linear regression to generate and odds ratios (OR). Results: Of the 1526 patients who were potentially eligible for alteplase therapy, 356 had a perfusion lesion <15mL with 211 being treated and 145 not treated with rtPA. Patients with a small perfusion lesion had similar NIHSS between those who were treated and those not treated (rtPA treated small lesion patients acute NIHSS, 8.2, untreated 8.9, p=0.71). The odds of small lesion patients achieving mRS 0-1 with alteplase was 0.614 (p<0.001). Average 24 hour DWI lesion in treated small perfusion lesion patients 3mL with alteplase treatment and 2.1mL without, p=0.081. The subgroup of patients with a small perfusion lesion associated with a vessel occlusion did however show an improvement in functional outcome (mRS 0-1OR 1.21, p=0.012). Conclusion: Ischemic stroke patients with a small perfusion lesion appear to have an excellent natural history regardless of alteplase treatment. Patients with a visible vessel occlusion may have a slight benefit from treatment.