Risk factors for neurological worsening and symptomatic watershed infarction in internal carotid artery aneurysm treated by extracranial-intracranial bypass using radial artery graft

Abstract

T he negative results of the Carotid Occlusion Surgery Study trial 21 and the introduction of flow-diverting stents 16 have resulted in many practitioners rethinking the utility of cerebral revascularization for vascular pathologies. However, revascularization techniques remain indispensable because of the need for complex reconstructions when endovascular therapies fail in patients with cerebral aneurysm. In addition, cerebral revascularization abbreviatioNs ECA = external carotid artery; EC-IC = extracranial-intracranial; ICA = internal carotid artery; IQR = interquartile range; MCA = middle cerebral artery; mRS = modified Rankin Scale; PCoA = posterior communicating artery; RA = radial artery; STA = superficial temporal artery; WI = watershed infarction. obJective The revascularization technique, including bypass created using the external carotid artery (ECA), radial artery (RA), and M 2 portion of middle cerebral artery (MCA), has remained indispensable for treatment of complex aneurysms. To date, it remains unknown whether diameters of the RA, superficial temporal artery (STA), and C 2 portion of the internal carotid artery (ICA) and intraoperative MCA blood pressure have influences on the outcome and the symptomatic watershed infarction (WI). The aim of the present study was to evaluate the factors for the symptomatic WI and neurological worsening in patients treated by ECA-RA-M 2 bypass for complex ICA aneurysm with therapeutic ICA occlusion. methods The authors measured the sizes of vessels (RA, C 2 , M 2 , and STA) and intraoperative MCA blood pressure (initial, after ICA occlusion, and after releasing the RA graft bypass) in 37 patients. Symptomatic WI was defined as presence of the following: postoperative new neurological deficits, WI on postoperative diffusion-weighted imaging, and ipsilateral cerebral blood flow reduction on SPECT. Neurological worsening was defined as the increase in 1 or more modified Rankin Scale scores. First, the authors performed receiver operating characteristic curve analysis for continuous variables and the binary end point of the symptomatic WI. The clinical, radiological, and physiological characteristics of patients with and without the symptomatic WI were compared using the log-rank test. Then, the authors compared the variables between patients with and without neurological worsening at discharge and at the 12-month follow-up examination or last hospital visit. results Symptomatic WI was observed in 2 (5.4%) patients. The mean MCA pressure after releasing the RA graft (< 55 mm Hg; p = 0.017), mean (MCA pressure after releasing the RA graft)/(initial MCA pressure) (< 0.70 mm Hg; p = 0.032), and mean cross-sectional area ratio ([RA/C 2 diameter] 2 < 0.40 mm [p < 0.0001] and [STA/C 2 diameter] 2 < 0.044 mm [p < 0.0001]) were related to the symptomatic WI. All preoperatively independent patients remained independent (modified Rankin Scale score < 3). After adjusting for age and sex, left operative side (p = 0.0090 and 0.038) and perforating artery ischemia (p = 0.0050 a...

Rationale for graft selection in patients with complex internal carotid artery aneurysms treated with extracranial to intracranial high-flow bypass and therapeutic internal carotid artery occlusion

“…Collected data included age, sex, smoking history, past medical history (hypertension, hypercholesterolemia, and diabetes mellitus), preoperative symptoms, size of aneurysm, aneurysm location, operative side, thrombosis or calcification of aneurysm, vessel diameters, intraoperative MCAPs (initial, after ICAO, and after release of the graft bypass), graft type, temporary occlusion time during bypasses, postoperative diffusion-weighted imaging (DWI) findings, aneurysm recurrence, follow-up period, graft patency, and outcome. 39,40 Taking into account back flow from the posterior communicating artery, the radius of the C 2 portion of the ICA, which was proximal to the posterior communicating artery, was measured as the radius of the ICA. An Allen test was performed to confirm an intact palmar arch and adequate hand perfusion despite occlusion of the radial artery (RA).…”

“…25 The STA-MCA bypass was performed not only as a backup for clamping the graft-MCA anastomosis, but also as a means of monitoring the MCAPs. 39,40 Continuous MCAP monitoring through this bypass was useful to check the patency of the graft after therapeutic ICAO. 27 The operative techniques for ECA-graft-MCA and STA-MCA bypasses and MCAP monitoring were recently published.…”

“…27 The operative techniques for ECA-graft-MCA and STA-MCA bypasses and MCAP monitoring were recently published. 39,40 The initial MCAP (iMCAP), MCAP after temporarily clamping the ICA (cMCAP), and MCAP after releasing the graft bypass (gMCAP) were monitored ( Fig. 1).…”

“…Our recent studies have shown that intraoperative MCA pressure (MCAP) can be used as a surrogate measure of regional cerebral perfusion pressure and that MCAPs have an impact on LRICs in complex ICA aneurysms treated with ECA-graft-MCA bypass and therapeutic ICAO. 39,40 We hypothesized that an adequate graft size could be calculated from the size of the sacrificed ICA and the MCAP values. This is the first study to investigate adequate graft size in patients with complex ICA aneurysms treated using the ECA-graft-MCA bypass and therapeutic ICAO.…”

Subarachnoid hemorrhage after surgical treatment of unruptured intracranial aneurysms

“…The surgical technique of extracranial to intracranial high-flow bypass was described previously. 26,27 The patients' clinical status was evaluated by means of the modified Rankin Scale (mRS) preoperatively, at discharge, and at 6-and 12-month follow-up examinations or the last hospital visit, 40 either via telephone interviews with the patient or family members or during a physical examination in cases in which patients were able to visit our hospital. For patients without symptoms, a poor outcome was defined as an mRS score of 2-6.…”