Ischemic stroke occurs when a person suffers a sudden blockage of an artery in their brain. Severe strokes caused by blockage of large brain arteries are treated with a very effective mechanical clot-removal procedure called thrombectomy. However, there are still unanswered questions regarding certain subgroups of thrombectomy-treated stroke patients.

One important and serious condition which affects about 15% of these patients is a simultaneous blockage or severe narrowing of the internal carotid artery (ICA) in the neck on the same side as the clot in the brain (« tandem lesion »). The brain artery clot causing the stroke is a fragment originating from a larger clot in the ICA. ICA clots usually result from an unstable plaque of atherosclerosis. During thrombectomy, the ICA lesion must be crossed by catheters to reach the brain clot. However, we do not know what to do with the ICA blockage during thrombectomy. Should it be left alone and possibly treated in the following days or weeks with surgery or stenting? Or rather, should it be unblocked and kept open with a stent immediately during the thrombectomy procedure? Answering this question will help patients have the best chance of recovery from their stroke.

Our goal is to determine the best way to treat the ICA lesion in patients with stroke who undergo thrombectomy and who suffer from both a brain clot and a blockage or narrowing of their neck ICA on the same side. Patients who participate will be randomly assigned to one of these two treatments for their ICA lesion. To determine which approach is best, we will compare how patients in both groups have recovered from their stroke by measuring their level of independence after three months and after one year. We will also measure the rates of major complications like recurrent strokes and bleeding.