Internal carotid artery pressures. A guide for use of shunt during carotid repair.

A safe and reliable technique of measuring internal carotid artery back pressure is described. Pressures are measured directly through a Javid bypass shunt. Internal carotid artery back pressure reflects pressure in the ipsilateral cerebral circulation from collateral arterial flow. During 40 carotid endarterectomies, the pressures in 23, or 58%, were below 50 mm Hg. On the basis of this experience we now proceed with the use of the shunt regardless of the back pressure in all instances where the anatomic setup is such that it can be used conveniently. We omit it only where the pressure is over 50 mm Hg and a narrowed internal carotid artery, or a long lesion, or other factors make the shunt inconvenient. If the pressure is below 50 mm Hg and the shunt is inconvenient, it must still be used.