Objective and importance In the setting of stroke intervention, there is typically an occlusion that limits angiographic visualization of patent vasculature distal to the embolus. Certain mechanical thrombectomy paradigms include angiography of the vasculature distal to the point of occlusion in preparation for thrombectomy, typically using a microcatheter. Injections using an intermediate catheter allows for higher volume of injection at a faster rate, resulting in radically different pressure gradients.

Clinical presentations Two patients presenting with acute ischemic stroke were treated via mechanical thrombectomy using the Penumbra 054 system. The first was a tandem occlusion with a high grade narrowing and occlusion of the internal carotid artery (ICA) origin and an ICA terminus thrombus. The second was a long segment, high volume thrombus extending from the cavernous segment to the ICA terminus.

Intervention Conventional access techniques were utilized to position the Penumbra 054 catheter in the ICA in both cases. Intraprocedurally, angiography through the 054 catheter within the closed segment resulted in contrast extravasation adjacent to the tentorium, originating from the communicating segment of the ICA, both of which cleared within 48 h. Due to the extravasation, the interventions were both terminated, and the infarcts went on to complete.

Conclusion During an acute stroke, flow within large vessels is abnormal, and rapid changes in volume may result in drastic changes in pressure which may lead to extravasation. The authors recommend never performing a contrast injection through a large lumen catheter when flow may be impeded proximally and distally. Closed segment injections of large volumes at a high rate are probably at high risk for vessel injury.