Time-to-treatment and stroke severity

This study looked at patients with ischemic stroke and investgated whether time of treatment with tissue plasminogen activator drug is important for providing effective treatment for different severity of strokes.

A stroke occurs when there is a disturbance of blood supply to a part of the brain. Most strokes are caused by blood clots (ischemic stroke). This blocks off oxygen and food reaching the brain tissue and can cause brain damage.

Treatment for ischemic stroke involves injecting a type of drug called tissue-type plasminogen activator (tPA) such as alteplase (Activase) into a patient’s vein. This drug breaks up blood clots and restores blood flow to the brain. However, the time when a patient receives treatment is critical because the longer the brain is deprived of oxygen, the more damage that can be done.

In general, tPA needs to be given within 3 hours of the first stroke symptoms in order to avoid damage and disability. However, it is not known whether this time window varies depending on stroke severity. 

This study investigated whether time of tPA treatment is important for different severities of stroke.

The study included 581 patients who were treated with alteplase after stroke onset. Patients were divided into categories of stroke severity (mild, moderate, and severe) according to the National Institues of Health Stoke Scale (NIHSS).

The study found that only 26% of those who had a severe stroke recovered with a favourable outcome with slight or no disability, compared to 60% with moderate stroke, and 79% with mild stroke reaching favorable outcomes.

The time of treatment did not seem to be associated with good outcomes for patients with mild or severe stroke. Instead, early treatment, in particular the first 120 minutes after stroke onset, only seemed to be of importance for patients with moderate stroke. These patients were nearly 3 times more likely to achieve a favorable outcome if they received early treatment.

The investigators concluded that receiving early treatment within 120 min (2 hours) of stroke onset is particulary important for patients with moderate stroke. Time of treatment seemed less effective for patients with mild and severe stroke, possibly because the severity of stroke is a much stronger influence on outcome. 

The study only had a small number of patients with severe stroke achieving good and favorable outcomes, therefore, the small number of patients this makes it hard to determine whether time of treatment had an effect or not. 

If you or someone you know are at risk of having a stroke, it is important for friends and family members to be aware that receiving early treatment is vital after a moderate stroke. Talk to a health care provider about how you can look out for the early signs and symptoms of stroke.