Intravenous tissue plasminogen activator treatment for ischemic stroke in dabigatran-treated patients

Abstract

Vergouwen et al. reported that intravenous tissue plasmin-ogen activator (IV tPA) treatment was not associated withan increased risk of secondary intracerebral hemorrhage orgastrointestinal hemorrhage in patients with acute ischemicstroke taking warfarin with an international normalizedratio (INR) <1.7 [6]. These results mean that IV tPAtreatment should not be discouraged in patients takingwarfarin with INR <1.7.Recently, dabigatran, a new oral anticoagulant, wasapproved by the FDA. In the Randomized Evaluation ofLong-Term Anticoagulant Therapy trial, dabigatran wasshown to be as effective as warfarin in prevention of systemicembolism and future stroke, with lower risk of majorhemorrhage [2]. Additionally, dabigatran does not needmonitoring (differently from warfarin). Therefore, the numberof dabigatran-treated patients presenting with ischemic strokemay increase in the future. However, there is no guidelinewhether dabigatran-treated patients presenting with ischemicstroke can be considered eligible for IV tPA treatment or not.Only two case reports demonstrated the safety of IV tPAtreatment for acute ischemic stroke in dabigatran-treatedpatient [3, 5]. On the other hand, Ammollo et al. reportedthat dabigatran enhanced the susceptibility of plasma clots totPA-induced lysis in in vitro study [ 1]. Based on Ammollo’sresults, we can hypothesize that dabigatran may also enhancethebleedingriskcausedbytPA.Although we recognize the lack of data on IV tPAtreatment for acute ischemic stroke in dabigatran-treatedpatients, we need provisional guidelines of the topic, asearly as possible, in order to avoid confusion. Some tests,such as activated partial thrombin time and ecarin clottingtime, which have been reported as correlated with dabiga-tran concentrations, can be helpful for clinicians todetermine the indication of IV tPA for such patients [4].