Ischemic strokes occur when a blockage forms in one of the arteries supplying blood to the brain. Patients who show signs of blockage in a major brain blood vessel and seek medical treatment within 24 hours of stroke onset may be treated through a catheter-based procedure that quickly restores blood flow by capturing and removing the blood clot from the affected vessel.

Many hospitals use the thrombolysis in cerebral infarction (TICI) scale to assess the effectiveness of endovascular treatments. The more open a blood vessel is after treatment, the easier it is for blood to flow through it.

In 2015, the Endovascular Stroke Standards Committee of the Society of Vascular and Interventional Neurology set a national benchmark for hospitals: At least 50% of ischemic stroke patients undergoing endovascular treatment must achieve a TICI grade of 2b or higher. The 2b grade indicates the vessel fills completely with blood, though the flow rate may be slower than normal.