Low-dose tissue plasminogen activator and standard-dose tissue plasminogen activator in acute ischemic stroke in Asian populations: a review.

BACKGROUND The burden of stroke is becoming an important issue in Asian countries, where half of the world's population lives. In Western populations, standard-dose intravenous tissue plasminogen activator (tPA) at a dose of 0.9 mg/kg administered up to 4.5 h following acute ischaemic stroke has been shown to improve clinical outcomes. However, the dosage of tPA in Asian populations varies, partly influenced by treatment costs in developing countries and the perceived racial differences in treatment response. Furthermore, no randomized controlled trial of intravenous tPA thrombolysis has been carried out in Asia with the exceptions of observational and multicentre registries in Japan. SUMMARY OF THE REVIEW: This review aims to examine the current use of low-dose tPA in Asian populations with particular emphasis on its clinical benefits. Historically, the findings of 2-chain tPA (duteplase) trials in the early 1990s were the basis of low-dose tPA in Japan, and standard-dose tPA was chosen taking into account a pilot dose escalation study. Most of the trials incorporating low-dose tPA suggested that low-dose tPA has clinical efficacy comparable with the standard dose and that it is associated with a lower incidence of symptomatic haemorrhage. It follows that consensus regarding the dosage of tPA is wanting. CONCLUSIONS Standard-dose tPA would be a reasonable choice in Asian populations until the results are available from randomized controlled studies comparing low-dose with standard-dose tPA.