Balloon test occlusion of the internal carotid artery with stump pressure ratio and venous phase delay technique

Balloon test occlusion (BTO) is crucial before sacrificing parent arteries. We proposed a simple paradigm combining clinical tolerance with venous phase technique and stump pressure ratio as a criterion for sufficient collateral flow. Internal carotid artery (ICA) occlusion was considered safe for asymptomatic patients who exhibited less than 2 seconds of venous phase delay or had a stump pressure ratio greater than 60%. A total of 37 BTO procedures were performed on 31 patients. Twenty-three patients were monitored clinically and 3 were symptomatic. Venous phase comparison was performed on 27 patients, and 5 failed the test. The stump pressure was measured in all patients, and 7 patients failed the test. In summary, 7 patients failed the BTO, of which 6 received high-flow bypass and 1 of these 6 were symptomatic and exhibited stump pressure ratios less than 60% in the second BTO procedure. Occlusion of the ICA was performed on 29 patients. Only 1 patient developed delayed vasospasm and brain infarction. Adequate collateral flow may be indicated by a stump ratio of 60% or greater with or without a high-flow bypass. Combined with clinical assessment and venous phase technique, ICA occlusion may be a safe option that does not result in delayed ischemic complications.