NEW YORK (Reuters Health) – Using recombinant tissue plasminogen activator (rtPA) within existing licensing limits is fully justified by available data – but there’s not enough data to tell whether the current indications should be expanded to “clinically important subgroups of patients,” say the authors of a Cochrane Corner report in the June issue of Stroke.

The researchers, led by Dr. Joanna M. Wardlaw, from Western General Hospital in Edinburgh, UK, and colleagues, base their conclusions on a meta-analysis of 11 randomized controlled trials of rtPA for ischemic stroke. Together these trials included 2977 patients (99% were below age 80). In addition to studying safety and efficacy, the authors hoped to identify factors that would influence risks and benefits, as well as the maximum time window for treatment.

Most of the trials started treatment up to 6 hours after stroke onset, the authors say, whereas guidelines in many countries indicate that rtPA should be given within 3 hours.

rtPA significantly reduced the proportion of patients with poor outcome at 3 months, defined as a modified Rankin Scale score of 3 to 6 (on a scale of 0 to 6). The researchers estimate that for every 1000 patients treated during the first 6 hours, 60 fewer patients were dead or dependent 3 months later.

While treatment within 3 hours of onset was associated with better outcomes (odds ratio for being dead or dependent at 3 months, 0.64, p = 0.0008), treatment between 3 and 6 hours still had a positive impact (odds ratio 0.85, p = 0.04).

rTPA increased the risk of intracranial hemorrhage (ICH), but without significantly affecting the odds of early death. In fact, rtPA significantly reduced deaths from non-ICH causes.

Patients with moderate stroke appeared to benefit more from thrombolysis than patients with severe stroke, but the authors note that this analysis involved small samples.

To better tailor treatment to the individual patient, more research is needed about people over age 80, grades of stroke severity, stroke subtypes, comorbidities, aspirin use before stroke, findings on different kinds of brain imaging, and time to treatment, Dr. Wardlaw and colleagues conclude.

Reference:

Stroke 2010.