Occlusion of the Vertebral Artery.

The angiographic demonstration of an occluded vertebral artery in a patient with a brain-stem syndrome was first reported by Riechert in 1952, and similar cases have been described by various authors subsequently. The common site of the vertebral occlusion was in the area between the arch of the atlas and the junction of the vertebral arteries. Since routine brachial angiography has been initiated in this clinic, occlusion of the vertebral artery at this site has been noticed more frequently than expected. Despite good visualization of the vertebral artery, the injected contrast material sometimes stopped before the junction of the vertebral arteries, and the basilar artery was not demonstrated in a number of patients who did not have clinical evidence of vertebral or basilar artery occlusion. This observation has been mentioned by Sutton and Hoare (1951), and by Krayenbuhl and Ya,argil (1957a) and was considered by them to be due to technical failure or vascular spasm. This explanation did not seem satisfactory for many instances in which we encountered an apparent vertebral artery occlusion. Therefore a series of 150 consecutive brachial angiograms has been reviewed in order to determine the frequency with which occlusion of the vertebral artery with or without symptoms occurs, and if possible to elucidate further its clinical and physiological significance.