Embolic intracranial strokes: Catheter-directed thrombolysis

In the setting of acute ischemic stroke, an intra-arterial (IA) pharmacological approach allows catheter-directed delivery of thrombolytic agents to the clot, offering several potential advantages by comparison with systemic (intravenous, IV) thrombolysis. First, a smaller dose of thrombolytic agent is utilized, thereby minimizing systemic hemorrhagic side effects; at the same time, a high concentration of the agent is locally delivered to the occlusion site. Second, using direct fluoroscopic guidance, a microcatheter can be placed immediately next to or directly into the thrombus. Third, both continuous and bolus delivery of thrombolytics can be given, based on specific features of the clot and the degree of response to lysis, which can be directly visualized during a microcatheter angiogram. IA thrombolysis can be used for thrombi located within smaller vessels, such as distal M2 or M3 branches of the middle cerebral artery (MCA), which often cannot be reached with mechanical thrombectomy devices. The angiographic appearance of a normal intracranial arterial anatomy is shown in Fig. 2.1.