What is the benefit of IV alteplase in terms of time window?
The benefit of IV alteplase is time dependent, with earlier treatment within the therapeutic window leading to better outcomes. A brain imaging study is recommended to exclude ICH as part of the initial evaluation of patients potentially eligible for these therapies. A pooled analysis of 5 randomized trials comparing EVT with medical therapy alone found that the odds of improved disability outcomes at 90 days declined with longer time from symptom onset to arterial puncture. Noncontrast CT (NCCT) is effective to exclude ICH before IV alteplase administration and Magnetic resonance (MR) imaging (MRI) is also effective to exclude ICH before IV alteplase administration. CTA with CTP or MR angiography (MRA) with diffusion-weighted magnetic resonance imaging (DW-MRI) with or without MR perfusion is recommended for certain patients, and reducing the time interval from ED presentation to initial brain imaging can help to reduce the time to treatment initiation.