Re-canalization in acute ischemic stroke: the strategies

Thrombolytic stroke therapy is based on the "re-canalization hypothesis," i.e., that reopening of occluded vessels improves clinical outcome in acute ischemic stroke through regional reperfusion and salvage of threatened tissues. Re-canalization is an important predictor of stroke outcome in all the modalities of thrombolysis. Thrombolysis in acute ischemic stroke evolved from clinical trials with intravenous (IV) tissue plasminogen activator (tPA) to combination treatments with Intra-arterial (IA)/mechanical reperfusion techniques. The combined approach reduces time to initiation of treatment and may increase re-canalization and chances of a good clinical outcome. In IV thrombolysis overall re-canalization rate is 46.2% during the first 6-24 hrs. Intra-arterial thrombolysis has higher early re-canalization rate, 63.2%. The highest re-canalization rate is seen with mechanical thrombolysis, 83.6%. Other factors in addition to re-canalization: stroke severity, older age, systolic hypertension, location of arterial occlusion, collateral blood supply, and time from stroke onset to treatment play an important role in determining the clinical outcome following thrombolysis with tPA. Future trials should look at the interplay of various factors like re-canalization, reperfusion, and collateral flow and clot burden in the evaluation of reperfusion therapies in acute ischemic stroke.