Hidetoshi Matsukawa, Rokuya Tanikawa, Hiroyasu Kamiyama, Toshiyuki Tsuboi, Kosumo Noda, Nakao Ota, Shiro Miyata, Jumpei Oda, Rihee Takeda, Sadahisa Tokuda and Kyousuke Kamada
The revascularization technique, including bypass created using the external carotid artery (ECA), radial artery (RA), and M2 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 C2 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-M2 bypass for complex ICA aneurysm with therapeutic ICA occlusion.
The authors measured the sizes of vessels (RA, C2, M2, 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.
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/C2 diameter]2 < 0.40 mm [p < 0.0001] and [STA/C2 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 and 0.022) were related to neurological worsening at discharge (11 [29%] patients) and at the 12-month follow-up or last hospital visit (8 [22%] patients).
Results of the present study showed that the vessel diameter and intraoperative MCA pressure had impacts on the symptomatic WI and that operative side and perforating artery ischemia were related to neurological worsening in patients with complex ICA aneurysms treated by ECA-RA-M2 bypass.
Nakao Ota, Rokuya Tanikawa, Hirotake Eda, Takashi Matsumoto, Takanori Miyazaki, Hidetoshi Matsukawa, Takeshi Yanagisawa, Go Suzuki, Shiro Miyata, Jumpei Oda, Kosumo Noda, Toshiyuki Tsuboi, Rihei Takeda, Hiroyasu Kamiyama and Sadahisa Tokuda
Bilateral vertebral artery dissecting aneurysms (VADAs) have a poor prognosis because progressive enlargement of the aneurysms compresses the brainstem or causes subarachnoid hemorrhage. The trapping of 1 vertebral artery (VA) places increased hemodynamic stress on the contralateral VA and may lead to enlargement and rupture. Therefore, management strategies are controversial. This study describes a radical treatment for bilateral VADAs using bypass surgery.
Seven patients with bilateral VADAs were included. Three patients were treated by trapping of 1 VA via coiling or clipping at another hospital; the previously treated VA in 1 patient and the contralateral untreated VA in 2 patients subsequently enlarged. The other 4 patients presented without previous intervention and progressive enlargement of the aneurysms.
The post–coil embolization patients underwent V3–posterior cerebral artery (PCA) bypass and trapping. The other 4 patients underwent VA reconstruction via V3–V4 or V4–V4 bypass, with contralateral trapping on a separate day in 3 patients and observation in 1 patient. Perioperative complications included 1 case of cerebrospinal fluid leakage for which the patient required an additional operation, 1 case of dysphagia and facial palsy due to sigmoid sinus thrombosis, and 1 case of dysphagia. The long-term outcomes of these patients were favorable.
Patients with bilateral VADAs require treatment on both sides. If VA trapping is performed first, the treatment options for the other side are limited to V3-PCA bypass and trapping. This procedure is effective; however, it is also invasive and technically difficult. In cases of bilateral VADAs in which it is feasible to reconstruct 1 side, the best approach is to begin by reconstructing the VA that appears technically easiest, followed by trapping of the contralateral VADA. This strategy allows enough time to suture vessels because contralateral reverse flow is maintained.
Hidetoshi Matsukawa, Hiroyasu Kamiyama, Toshiyuki Tsuboi, Kosumo Noda, Nakao Ota, Shiro Miyata, Takanori Miyazaki, Yu Kinoshita, Norihiro Saito, Osamu Takahashi, Rihee Takeda, Sadahisa Tokuda and Rokuya Tanikawa
Only a few previous studies have investigated subarachnoid hemorrhage (SAH) after surgical treatment in patients with unruptured intracranial aneurysms (UIAs). Given the improvement in long-term outcomes of embolization, more extensive data are needed concerning the true rupture rates after microsurgery in order to provide reliable information for treatment decisions. The purpose of this study was to investigate the incidence of and risk factors for postoperative SAH in patients with surgically treated UIAs.
Data from 702 consecutive patients harboring 852 surgically treated UIAs were evaluated. Surgical treatments included neck clipping (complete or incomplete), coating/wrapping, trapping, proximal occlusion, and bypass surgery. Clippable UIAs were defined as UIAs treated by complete neck clipping. The annual incidence of postoperative SAH and risk factors for SAH were studied using Kaplan-Meier survival analysis and Cox proportional hazards regression models.
The patients’ median age was 64 years (interquartile range [IQR] 56–71 years). Of 852 UIAs, 767 were clippable and 85 were not. The mean duration of follow-up was 731 days (SD 380 days). During 1708 aneurysm years, there were 4 episodes of SAH, giving an overall average annual incidence rate of 0.23% (95% CI 0.12%–0.59%) and an average annual incidence rate of 0.065% (95% CI 0.0017%–0.37%) for clippable UIAs (1 episode of SAH, 1552 aneurysm-years). Basilar artery location (adjusted hazard ratio [HR] 23, 95% CI 2.0–255, p = 0.0012) and unclippable UIA status (adjusted HR 15, 95% CI 1.1–215, p = 0.046) were significantly related to postoperative SAH. An excellent outcome (modified Rankin Scale score of 0 or 1) was achieved in 816 (95.7%) of 852 cases overall and in 748 (98%) of 767 clippable UIAs at 12 months.
In this large case series, microsurgical treatment of UIAs was found to be safe and effective. Aneurysm location and unclippable morphologies were related to postoperative SAH in patients with surgically treated UIAs.
Hidetoshi Matsukawa, Shiro Miyata, Toshiyuki Tsuboi, Kosumo Noda, Nakao Ota, Osamu Takahashi, Rihee Takeda, Sadahisa Tokuda, Hiroyasu Kamiyama and Rokuya Tanikawa
After internal carotid artery (ICA) sacrifice without revascularization for complex aneurysms, ischemic complications can occur. In addition, hemodynamic alterations in the circle of Willis create conditions conducive to the formation of de novo aneurysms or the enlargement of existing untreated aneurysms. Therefore, the revascularization technique remains indispensable. Because vessel sizes and the development of collateral circulation are different in each patient, the ideal graft size to prevent low flow–related ischemic complications (LRICs) in external carotid artery (ECA)–middle cerebral artery (MCA) bypass with therapeutic ICA occlusion (ICAO) has not been well established. Authors of this study hypothesized that the adequate graft size could be calculated from the size of the sacrificed ICA and the values of MCA pressure (MCAP) and undertook an investigation in patients with complex ICA aneurysms treated with ECA-graft-MCA bypass and therapeutic ICAO.
In the period between July 2006 and January 2016, 80 patients with complex ICA aneurysms were treated with ECA-MCA bypass and therapeutic ICAO. Preoperative balloon test occlusion (BTO) was performed, and the BTO pressure ratio was defined as the mean stump pressure/mean preocclusion pressure. Low flow–related ischemic complications were defined as new postoperative neurological deficits and ipsilateral cerebral blood flow reduction. Initial MCAP (iMCAP), MCAP after clamping the ICA (cMCAP), and MCAP after releasing the graft (gMCAP) were intraoperatively monitored. The MCAP ratio was defined as gMCAP/iMCAP. Based on the Hagen-Poiseuille law, the expected MCAP ratio ([expected gMCAP]/iMCAP) was hypothesized as follows: (1 – cMCAP/iMCAP)(graft radius/ICA radius)2 + (cMCAP/iMCAP). Correlations between the BTO pressure ratio and cMCAP/iMCAP, and between the actual and expected MCAP ratios, were evaluated. Risk factors for LRICs were also evaluated.
The mean BTO pressure ratio was significantly correlated with the mean cMCAP/iMCAP (r = 0.68, p < 0.0001). The actual MCAP ratio correlated with the expected MCAP ratio (r = 0.43, p < 0.0001). If the expected MCAP ratio was set up using the BTO pressure ratio instead of cMCAP/iMCAP (BTO-expected MCAP ratio), the mean BTO-expected MCAP ratio significantly correlated with the expected MCAP ratio (r = 0.95, p < 0.0001). During a median follow-up period of 26.1 months, LRICs were observed in 9 patients (11%). An actual MCAP ratio < 0.80 (p = 0.003), expected MCAP ratio < 0.80 (p = 0.001), and (M2 radius/graft radius)2 < 0.49 (p = 0.002) were related to LRICs according to the Cox proportional-hazards model.
Data in the present study indicated that it was important to use an adequate graft to achieve a sufficient MCAP ratio in order to avoid LRICs and that the adequate graft size could be evaluated based on a formula in patients with complex ICA aneurysms treated with ICAO.