Is taking clopidogrel with aspirin the best way to prevent stroke after transient ischemic attack?

This study looked at whether taking clopidogrel with aspirin, rather than aspirin alone, provides better protection against the onset of major stroke after the occurrence of minor stroke or transient ischemic attack.

A stroke occurs when there is a disturbance of blood supply to a part of the brain. This can be caused by a blood clot in the brain (ischemic stroke) or a burst blood vessel (hemorrhagic stroke). Both types of stroke result in a lack of oxygen and food reaching the brain tissue and can cause brain damage.

Often stroke patients experience a transient ischemic attack or minor stroke within the weeks or year before a major stroke. A transient ischemic attack or minor stroke are like strokes, producing similar symptoms such as numbness in face, arm of leg, slurred speech, vision loss and dizziness, but usually last only a few minutes and cause no permanent damage. Therefore, these minor stroke events can serve as both as a warning of an impending stroke and as an opportunity to take preventative steps.

Medications used to decrease the likelihood of a stroke after minor stroke events include anti-platelet drugs such as aspirin and clopidogrel (Plavix). These drugs thin the blood and stop the blood from clotting and hence help prevent an ischemic stroke. Generally anti-platelet drugs such as aspirin and clopidogrel are prescribed alone. Aspirin is more widely used as it is less expensive and has fewer side effects. 

This study investigated if combining the two treatments provides greater protection against subsequent stroke rather than taking aspirin alone.

In this study, 5,170 patients were prescribed clopidogrel with aspirin or a placebo plus aspirin within 24 hours of a minor ischemic stroke or a transient ischemic attack. Clopidogrel was used at an initial dose of 300 mg, followed by 75 mg per-day for 90 days, plus aspirin at a dose of 75 mg per-day for the first 21 days. People that received aspirin plus placebo (substance with no therapeutic effect) were given 75 mg per-day of aspirin for 90 days.

Over 90 days of follow up, the occurrence of stroke was recorded. Stroke occurred in 8.2% of patients in the clopidogrel–aspirin group, as compared with 11.7% of those in the aspirin group. A side effect of excessive blood thinning with anti-platelets includes increased incidence of hemorrhages (internal bleeding), however this study found that brain hemorrhage occurred in 7 patients (0.3%) in the clopidogrel–aspirin group and in 8 (0.3%) in the aspirin group. 

This study found that among patients with transient ischemic stroke or minor stroke, who can be treated within 24 hours after the onset of symptoms, that combination of clopidogrel and aspirin is superior to aspirin alone for reducing the risk of stroke in the first 90 days and does not increase the risk of hemorrhage.

The study only measured the occurrence of stroke for 90 days; however, people can have major strokes up to 1 year after a transient ischemic attack or minor stroke. Therefore longer follow-ups are warranted to gain a full picture. 

If you or someone you know have had or are at risk of having a transient ischemic stroke or a minor stroke, talk to a doctor about anti-platelet medications that can be given in order to reduce the likelihood of subsequent stroke.