Does low-dose intravenous alteplase offer benefits over standard-dose intravenous alteplase in older, Asian, or severely affected patients with acute ischemic stroke?
This secondary analysis of a randomized clinical trial that involved 3310 patients with acute ischemic stroke found no clear differential benefits of low-dose alteplase compared with standard-dose alteplase in disability outcomes, irrespective of age, race/ethnicity, and neurological severity. Increasing age and neurological severity, but not ethnicity, are associated with greater risk of death or disability following acute ischemic stroke in treated, thrombolysis-eligible patients.
Decisions about using a lower dose of alteplase for thrombolysis-eligible patients with acute ischemic stroke should not be based solely on age, ethnicity, or neurological severity.
A lower dose of intravenous alteplase appears to be a safer treatment option than the standard dose, reducing the risk of symptomatic intracerebral hemorrhage. There is uncertainty, however, over how this effect translates into an overall clinical benefit for patients with acute ischemic stroke (AIS).
To assess whether older, Asian, or severely affected patients with AIS who are considered at high risk of thrombolysis may benefit more from low-dose rather than standard-dose alteplase treatment.
Design, Setting, and Participants
This study is a prespecified secondary analysis of the Enhanced Control of Hypertension and Thrombolysis Stroke Study (ENCHANTED), an international, randomized, open-label, blinded, end-point clinical trial of low-dose vs standard-dose intravenous alteplase for patients with AIS. From March 1, 2012, to August 31, 2015, a total of 3310 patients who had a clinical diagnosis of AIS as confirmed by brain imaging and who fulfilled the local criteria for thrombolysis treatment were included in the alteplase-dose arms. Patients were randomly assigned to receive low-dose (0.6 mg/kg; 15% as bolus and 85% as infusion over 1 hour) or standard-dose (0.9 mg/kg; 10% as bolus and 90% as infusion over 1 hour) alteplase. Of the 3310 randomized patients, 13 patients were excluded for missing consent, mistaken randomization, and duplicate randomization numbers. This secondary analysis was conducted between May 1, 2016, and April 28, 2017.
Main Outcomes and Measures
The primary end point was a poor outcome defined by the combination of death and any disability as scored by the modified Rankin Scale (scores range from 2 to 6, with the highest score indicating death) at 90 days.
Of the 3297 patients included in the analysis, 1248 (37.9%) were women, and the mean (SD) age was 67 (13) years. No significant differences in the treatment effects were observed between low- and standard-dose alteplase for poor outcomes (death or disability) by age, ethnicity, or severity (all P > .37 for interaction). Similarly, the treatment effects of low- vs standard-dose alteplase on function outcome (ordinal shift of the modified Rankin Scale) in Asians (odds ratio, 1.05; 95% CI, 0.90-1.22) was consistent with non-Asians (odds ratio, 0.93; 95% CI, 0.76-1.14) (P = .32 for interaction). There were generally consistent reductions in rates of symptomatic intracerebral hemorrhage with low-dose alteplase, although this reduction was not statistically significant by age, ethnicity, or severity.
Conclusions and Relevance
This analysis found that the effects of low-dose alteplase were not clearly superior to the effects of standard-dose alteplase on death or disability in key demographic subgroups of patients with AIS. Further investigation is required to identify patients with AIS who may benefit from low-dose alteplase.
clinicaltrials.gov Identifier: NCT01422616
Wang X, Robinson TG, Lee T, Li Q, Arima H, Bath PM, Billot L, Broderick J, Demchuk AM, Donnan G, Kim JS, Lavados P, Lindley RI, Martins SO, Olavarria VV, Pandian JD, Parsons MW, Pontes-Neto OM, Ricci S, Sharma VK, Thang NH, Wang J, Woodward M, Anderson CS, Chalmers J, for the Enhanced Control of Hypertension and Thrombolysis Stroke Study (ENCHANTED) Investigators. Low-Dose vs Standard-Dose Alteplase for Patients With Acute Ischemic StrokeSecondary Analysis of the ENCHANTED Randomized Clinical Trial. JAMA Neurol. Published online October 02, 2017. doi:10.1001/jamaneurol.2017.2286