Permeable Thrombi Are Associated With Higher Intravenous Recombinant Tissue-Type Plasminogen Activator Treatment Success in Patients With Acute Ischemic Stroke

Abstract

Background and Purpose—: Preclinical studies showed that thrombus permeability improves recombinant tissue-type plasminogen activator (r-tPA) efficacy. We hypothesize that thrombus permeability estimated from radiological imaging is associated with improved recanalization after treatment with intravenously administered r-tPA (r-tPA) and with better functional outcome. Methods—: We assessed thrombus attenuation increase (TAI) in patients from the Dutch Acute Stroke Study with an occlusion of an intracranial artery on computed tomographic angiography. Patients were included within 9 hours after the stroke onset. After dichotomization of TAI as pervious or impervious, logistic regressions analyses were performed to estimate associations of intravenous r-tPA therapy with complete recanalization and with favorable functional outcome (modified Rankin Scale score of ≤2). Results—: Three hundred eight patients matched the inclusion criteria. The median TAI was 20.1 (interquartile range, 8.5–37.8) Hounsfield unit (HU). We found a significant increase in the odds of complete recanalization with increasing TAI for patients treated with intravenous r-tPA ( P =0.030). One hundred thirty-one (42%) thrombi were classified as pervious with TAI of ≥23 HU. In patients with a pervious thrombus, complete recanalization was more frequent after treatment with intravenous r-tPA than after conservative treatment (odds ratio, 6.26; 95% confidence interval, 2.4–16.8; P P =0.47). Favorable outcome was more common in patients with a pervious thrombi than without (odds ratio, 2.1; 95% confidence interval, 1.3–3.4; P =0.001). Conclusions—: Thrombus perviousness, as measured on computed tomography in the acute stage of ischemic stroke, is strongly associated with recanalization after intravenous r-tPA treatment and with favorable functional outcome.