An “ischemic” stroke is an injury to the brain caused by a blocked blood vessel supplying the brain. Known causes of stroke include a narrowing of a large blood vessel supplying the brain, an abnormal heart beat rhythm, or blockage of a single very small blood vessel in the brain. For one out of three cases, these causes of ischemic stroke are not found, and a stroke is considered to have an “undetermined source”. Your doctors have found that you have had an ischemic stroke of undetermined source, which makes you eligible for this research study. Atrial fibrillation is a common cause of ischemic stroke. Atrial fibrillation is an irregular heart rate. You do not have atrial fibrillation. You may have a related condition called “atrial cardiopathy.” We think that patients with some markers (signs or indications) of atrial cardiopathy may develop atrial fibrillation in the future. These patients may be at risk of having an ischemic stroke before atrial fibrillation develops. The three markers of atrial cardiopathy being tested in this study are an:
- Enlarged left atrium, a chamber of the heart
- Elevated blood test called NT-proBNP;
- Abnormality of the P wave on the electrocardiogram, an indication of abnormal electrical activity of the heart
In people with atrial fibrillation, blood clots can form in the heart. These clots can break free, travel to the brain, block an artery, and cause a stroke. Blood thinners are the best way to minimize the risk of stroke in patients with atrial fibrillation. Apixaban (also known as Eliquis®) is one such type of blood thinner. Most patients with ischemic stroke and no evidence of atrial fibrillation are prescribed a mild blood thinner such as aspirin.
The purpose of this research study is to compare the effects (good and bad) of apixaban with the effects (good and bad) of aspirin in patients with unexplained strokes and atrial cardiopathy to see which is better at prevention of future strokes. The use of apixaban for stroke prevention in ischemic stroke patients like you, without atrial fibrillation, is not approved by the U.S. Food and Drug Administration (FDA) and is considered investigational in this research study. Aspirin is the standard of care blood thinner used for stroke prevention in patients like you.
About 1,100 people will take part in this study.