Purpose: The purpose of this study was to evaluate the reliability of angiography-based balloon test occlusion (BTO) criteria to decide whether to perform internal carotid artery (ICA) permanent occlusion.
Methods: From March 1999 to August 2004, 60 patients underwent therapeutic ICA occlusion. Angiographic BTO was performed systematically in all patients under general anesthesia (GA). No clinical examination test was performed. After balloon inflation, contralateral carotid and vertebral arteries angiograms were obtained. The symmetry of the venous phases of each hemisphere was assessed. Occlusion was considered to be feasible when the delay between the venous drainage of the injected and the occluded hemisphere was not >2 seconds. Venous drainage delay >4 seconds was considered as contraindication to ICA permanent occlusion. In patients with venous drainage delay of 2-4 seconds, the occlusion was performed only in selected cases.
Results: From a total of 60 patients, 44 had exact symmetry of the venous phase, 10 had delay of 1 second, and 3 other patients had 2-second delays. Clinical outcome for these 57 patients was uneventful. Three patients had venous drainage delay of 3 seconds. One of them had delayed watershed area infarction without clinical consequences at the time of hospital discharge. No periprocedural complications were observed.
Conclusion: Venous opacification symmetry in the tested and control vascular territories was a reliable predictor of a subject's ability to tolerate carotid occlusion without developing neurologic deficit. Carotid sacrifice was found to be possible when the delay was <3 seconds.