Hemodynamics in and around the Ischemic Focus: A Local Angiographic Study via Catheterization to the Middle cerebral Artery of the Cat

Local hemodynamics in and around the ischemic focus following middle cerebral artery occlusion (MCA) were investigated on angiography by direct infusion of contrast material into the MCA. In anesthetized cats, a catheter was introduced just distal to the site of MCA occlusion through the transorbital approach. MCA stump pressure following occlusion was approximately 20 mmHg. Solute infusion with hydrostatic pressure exceeding stump pressure by approximately 20 mmHg was found to be sufficient to perfuse the entire territory of the MCA. Serial angiography revealed that cortical MCA branches were fully opacified first, and within 10 seconds disappeared centrifugally from the penumbral area. When vessels were occluded together with the internal carotid artery and anterior cerebral artery, backflow was delayed such that the contrast material remained longer within the ischemic focus. This new technique provides a sound basis not only for investigating local hemodynamics but also for direct pharmacological manipulation of the ischemic vessels and brain tissues.