Balloon Test Occlusion as a Preoperative Evaluation for Cerebral Aneurysms Treated with Bypass Surgery

Abstract

Summary:For the treatment of patients with complex internal carotid artery (ICA) aneurysms, it may be necessary to occlude the parent artery following a bypass surgery. The bypass surgery may be low or high flow bypass, but selection criteria have not been established. We retrospectively analyzed our method using preoperative balloon test occlusion (BTO).Thirty-five patients with ICA aneurysms, 15 ruptured and 20 unruptured, were treated with parent artery occlusion with bypass surgery. Preoperative BTO was performed in 27 cases (all unruptured and 7 ruptured, chronic stage cases). When ischemic symptoms occurred during BTO, high flow bypass was performed followed by parent artery occlusion. Otherwise, single-photon emission computed tomographic findings during BTO were used for the bypass selection. If ipsilateral residual blood flow was 70-75% or less of the contralateral hemisphere, high flow bypass was chosen and if between 70-75% and 90%, superficial temporal artery-middle cerebral artery (STA-MCA) bypass was employed. In the acute stage of 8 ruptured cases, BTO was not performed and bypass selection was made according to angiographic findings only. After completion of the bypass, ipsilateral ICA occlusion (ICO) was performed either by direct or intravascular technique. The site of ICO was determined to completely block the blood flow into the aneurysm considering both conventional angiography and BTO findings.A total of 15 STA-MCA and 20 high flow bypasses were performed followed by ICO. There was no mortality or morbidity in unruptured cases. In ruptured cases, there were 3 complications related to surgical procedure such as perforator injury, but no patients showed insufficient ipsilateral cerebral blood flow postoperatively. One asymptomatic cerebral infarction developed due to BTO. In 5 cases, petrous portion collateral flow from external to internal carotid artery was seen, and the ICO was performed above the collateral using intravascular embolization.

Ophthalmic Artery Flow Pattern-related Stump Pressure and Ischemic Tolerance during Balloon Test Occlusion of the Internal Carotid Artery

“…The thromboembolic complication rate associated with BTO was reported to be 0.8%-6.0%. [12][13][14][15][16] In most facilities, a 20-min temporary ICA occlusion is performed to evaluate the neurological symptoms during BTO. Our findings suggest that patients with type III OphA flow can avoid this 20-min temporary ICA occlusion.…”

“…BTO is an invasive test associated with thromboembolic complications of 0.8-6.0%, [12][13][14][15][16] partly due to the prolonged ICA occlusion. To reduce the complication rate, we focused on determination of the ophthalmic artery (OphA) flow direction just after ICA temporary occlusion because OphA flow direction might be associated with intracranial collateral perfusion.…”

Giant Internal Carotid Artery Aneurysm Manifesting as Difficulty in Swallowing -Case Report-

“…Although there is no consensus regarding the indications for this procedure, balloon test occlusion (BTO), based on evaluation of clinical signs, stump pressure, and measurement of cerebral blood flow, has been used to determine the need for bypass (low flow or high flow) or non-bypass. 3,6,9,16) However, the BTO test is not without risk 14) and is also plagued with the possibility of false negative findings. 10) Moreover, use of only a low flow bypass procedure may be inadequate to prevent ischemic events, 17) and in patients younger than 75 years of age without major systemic diseases, high flow bypass should be performed without use of the BOT.…”