Reduced rtPA dose supported for Chinese stroke patients
MedWire News: Chinese stroke patients appear to have better outcomes with a lower than standard dose of recombinant tissue plasminogen activator (rtPA), results of the Taiwan Thombolytic Therapy for Acute Ischemic Stroke study indicate.
rtPA for coronary thrombolysis is used at a reduced dose in China and Japan, and rtPA for stroke is approved at a dose of 0.6 mg/kg in Japan – lower than the 0.9 mg/kg dose used in Europe and the USA.
Because of this, some neurologists in the current study “inferred that the dose of rtPA for acute ischemic stroke should also be reduced for safety concerns,” say explain authors Han Hwa Hu (Taipei Veterans General Hospital, Taiwan) and colleagues.
“Therefore, approximately half of the patients received lower doses of rtPA.”
They say: “Although this was also a kind of protocol violation, we were able to observe and analyze the differences in the safety/efficacy outcomes between the standard- and lower-dose groups.”
In all, 51.8% of the 241 patients received the “standard” dose of 0.9 mg/kg, while the others received less than 0.85 mg/kg (median 0.7 mg/kg, range 0.55–0.84 mg/kg). There were no significant differences in baseline characteristics between the two groups.
Patients in the standard-dose group had double the rate of symptomatic intracerebral hemorrhage (ICH) and mortality within 3 months than did those in the lower-dose group, the team reports in the journal Stroke.
Corresponding mortality rates were 12.8% versus 6.9%, while symptomatic ICH rates were 8.0% versus 2.6% using the European Cooperative Acute Stroke Study definition of parenchymatous hemorrhage within 36 hours accompanied by a 4-point increase in National Institutes of Health Stroke Scale score. Similar results were obtained with other ICH definitions.
The increased risk was particularly notable among the 112 patients aged 70 years or older. The mortality rate was 21.1% in the standard-dose group versus 5.0% in the lower-dose group and the corresponding rates of symptomatic ICH were 15.4% versus 3.3%.
Older patients were also less likely than those younger than 70 years to be functionally independent after 3 months (modified Rankin Scale 0–2), at 32.6% versus 53.6%.
“Our study did not support use of standard-dose alteplase for treatment of acute ischemic stroke in Chinese patients, particularly for the aged groups,” conclude Hu et al.
But they caution: “The dose of rtPA for Chinese patients should be based on more broad and convincing evidence.”
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By Eleanor McDermid