High-flow EC-IC Bypass Research Articles

How I do It: High flow EC-IC bypass for complex middle cerebral artery aneurysms using the lateral circumflex femoral artery as interposition graft.

High-flow bypasses with parent vessel occlusion are required for complex aneurysms originating from the ICA or MCA. Traditional graft options are the saphenous vein however, it has a higher rate of thrombus formation than an arterial graft. The radial artery is commonly used, however, tapers in its distal course and is contraindicated in some patients while the lateral circumflex femoral artery is an excellent graft vessel and easy to harvest. We present our technique and experience harvesting the lateral circumflex femoral artery as an alternative graft vessel for high-flow bypasses. The lateral circumflex femoral artery is easy to harvest and is a reliable graft vessel for high-flow bypasses for complex aneurysms.

Consecutive low-flow and high-flow EC-IC bypass in ischemia prevention during internal carotid artery sacrifice in intracavernous aneurysm

Consecutive low-flow and high-flow EC-IC bypass in ischemia prevention during internal carotid artery sacrifice in intracavernous aneurysm

Cerebral revascularization by EC-IC bypass in ischemic conditions of different etiologies

Background: Even after the failure of EC-IC bypass trial, EC- IC bypass can help many patients in preventing future stroke. Here we present a case series of patients with cerebral ischemia from different etiological modes who underwent EC-IC bypass with positive end results. Methods: Patients in these cases series with TIA/stroke/recurrent stroke were evaluated clinically for the history of TIA or recurrent/hemodynamic TIA (in rest or during work) or progressive hemiparesis/aphasia/visual disturbances or sudden hemiplegia/hemiparesis/aphasia with subsequent significant (days to a week) recovery. MRI of the brain was done in ischemic protocol in all cases. To see the arterial pathology dynamic CTA was also done in all cases except one case. DSA was done in 03 cases. When clinical features, cerebral ischemia on MRI and arterial stenosis/occlusion on angiogram were concordant with each other, only then cerebral revascularization was done. After bypass, all patients were followed up regularly. All recorded data were reviewed retrospectively. Results: Total no. of cases were 08. The most common presentation was hemiparesis. Etiologies were infective thrombosis of ICA, orbital cellulitis, thrombosed giant ICA aneurysm, single & multiple vessel occlusion and MCA stenosis. High flow EC-IC bypass was done in one case. STA- MCA bypass was done in rest of the cases. All patient were ambulant with static neuro-status without new stroke till last follow up. All bypasses were patent and functioning till last follow up (clinical, Doppler/Imaging). Conclusion: In carefully selected cases cerebral revascularization in ischemic conditions can result positive outcome.

Extracranial-Intracranial High-Flow Bypass with Internal Carotid Artery Ligation at Neck for Giant Cavernous Internal Carotid Artery Dissecting Aneurysm in a Teen Girl with Postoperative Unusual Complication of Mono-ocular Blindness: A Case Report

AbstractExtracranial-intracranial (EC-IC) high-flow bypass with internal carotid artery (ICA) ligation at the neck is an important treatment option for giant cavernous ICA dissecting aneurysm. Such treatment may be associated with many complications. We report a case that developed postoperative mono-ocular blindness. So far to our knowledge such complication has not been reported in the literature. A 14-year-old girl presented with recent headache, eye ache, occasional double vision, and occasional right-sided visual impairment. Neurologic examination revealed no abnormality. Computed tomographic (CT) scan of the head showed a large, right parasellar, and mostly hyperdense space-occupying lesion. CT angiogram of the brain showed giant dissecting aneurysm of right-sided cavernous segment ICA. A right-sided external carotid artery–radial artery graft–middle cerebral artery (ECA-RAG-MCA [M2]) high-flow bypass was done with ligation of the right ICA in the neck. Postoperatively, the patient developed complete, mono-ocular, and permanent blindness on right side. Mono-ocular blindness is a serious complication from ophthalmic/central retinal artery thrombosis in high-flow EC-IC bypass with ICA ligation. Strategy is required to find and to set for its prevention.

Four-Dimensional Flow MRI Analysis of Cerebral Blood Flow Before and After High-Flow Extracranial–Intracranial Bypass Surgery With Internal Carotid Artery Ligation

The hemodynamic changes that occur after high-flow (extracranial-intracranial) EC-IC bypass surgery with internal carotid artery (ICA) ligation are not well known. To assess blood flow changes after high-flow EC-IC bypass with ICA ligation by time-resolved 3-dimensional phase-contrast (4D Flow) magnetic resonance imaging (MRI). We enrolled 11 patients who underwent high-flow EC-IC bypass. 4D Flow MRI was performed before and after surgery to quantify the blood flow volume (BFV) of the ipsilateral ICA (BFViICA), bypass artery (BFVbypass), contralateral ICA (BFVcICA), and basilar artery (BFVBA). Subsequently, we calculated the total BFV (BFVtotal=BFViICA+BFVcICA+BFVBA [before surgery], BFVcICA+BFVBA+BFVbypass [after surgery]). The BFV changes after bypass was statistically analyzed. BFVbypass was slightly lower than BFViICA, but the difference was not statistically significant (3.84±0.94 vs 4.42±1.38 mL/s). The BFVcICA and BFVBA significantly increased after bypass surgery (BFVcICA 5.89±1.44 vs 7.22±1.37 mL/s [P=.0018], BFVBA 3.06±0.41 vs 4.12±0.38 mL/s [P<.001]). The BFVtotal significantly increased after surgery (13.37±2.58 vs 15.18±1.77 mL/s [P=.015]). There was no evidence of hyperperfusion syndrome in any cases. After high-flow EC-IC bypass with permanent ICA ligation, the bypass artery could partially compensate for the loss of BFV of the sacrificed ICA. The increased flow of the contralateral ICA and BA supply collateral blood flow. Clinically irrelevant hyperperfusion was observed.

Protective STA-MCA bypass to prevent brain ischemia during high-flow bypass surgery: case series of 10 patients

High-flow extracranial-intracranial bypass is associated with a significant risk of ischemic stroke. The goal of this study is to evaluate the effectiveness of STA-MCA bypass preceding a high-flow bypass as a means of protecting the brain from ischemia during the high-flow bypass anastomosis in patients with otherwise untreatable aneurysms. This prospective study included 10 consecutive patients treated for complex/giant aneurysm using a previous combined STA-MCA bypass and high-flow EC-IC bypass between June 2016 and January 2018 when classical endovascular or microsurgical exclusion was estimated too risky. Early cranial Doppler, MRI, CT scan, and conventional angiography were performed in each patient to confirm patency of bypasses, measure flow in the anastomoses, detect any ischemic lesions, and evaluate exclusion of the aneurysm. The mean age at treatment was 55years (range 34 to 67). The mean time of microsurgical procedure was 11h (range 9 to 12). In all patients, the high-flow bypass was patent intraoperatively and complete occlusion of aneurysm was obtained. No ischemic lesions were noted on early MRI. One patient died from a large hemispheric infarction related to a common carotid artery dissection 10days after the microsurgical procedure and immediate postoperative epidural hematoma was noted in one other patient. In this study, we described the use of a protective STA-MCA bypass, performed prior to the high-flow bypass, in order to reduce the risk of perioperative ischemic lesions without increasing the morbidity of the surgical procedure. This treatment paradigm was feasible in all ten patients without complications related to the STA-MCA anastomosis.

Microsurgical treatment of paraclinoid aneurysms

Objective: To explore the microsurgical treatment of paraclinoid aneurysms and evaluate its safety and efficacy. Methods: The data of 21 patients with 22 paraclinoid aneurysms receiving craniotomy between Jan. 2010 and Dec. 2017 in Peking University First Hospital were retrospectively analyzed. According to the Barami K classification, 2 aneurysms were type Ⅰa, 6 type Ⅰb,7 typeⅡ,6 type Ⅲa,1 type Ⅳ. Out of the 17 cases of saccular aneurysms, 16 aneurysms were clipped and one aneurysm was trapped following high-flow EC-IC bypass. Out of the 5 cases of blood blister like aneurysms, 2 aneurysms were wrap-clipped, 2 aneurysms were trapped following high-flow EC-IC bypass and 1 aneurysm was trapped following STA-MCA bypass. The patients were reexamined with CT angiography (CTA) or digital subtraction angiography (DSA) and followed up in outpatient or by phone call. Results: Seventeen patients with 18 paraclinoid aneurysms had received aneurysm clipping. Aneurysmal neck remnant was found in 2 cases, parent artery stenosis was found in 2 cases. In all of the four bypass cases, graft artery patency was confirmed and no recurrence of aneurysm was observed. The obliteration rate of the paraclinoid aneurysm was 91%(20/22). Eight cases with preoperative vision defect had recovered to some extent. New vision defect occurred in two cases. At discharge, 12 patients scored with Glasgow outcome scale 5, 6 patients scored 4, 2 patients scored 3, and one patient scored 1. Conclusion: Microsurgical treatment for paraclinoid aneurysm is a safe and effective method with high aneurysm obliteration rate and low aneurysm recurrence rate, and is thus a reasonable and effective complementary method for endovascular treatment.

Surgical Technique for High-Flow Internal Maxillary Artery to Middle Cerebral Artery Bypass Using a Superficial Temporal Artery Interposition Graft.

Extracranial-to-intracranial high-flow bypass often requires cranial, cervical, and graft site incisions. The internal maxillary artery (IMA) has been proposed as a donor to decrease invasiveness, but its length is insufficient for direct intracranial bypass. We report interposition of a superficial temporal artery (STA) graft for high-flow IMA to middle cerebral artery (MCA) bypass using a middle fossa approach. To assess the feasibility of an IMA-STA graft-MCA bypass using a new middle fossa approach. Twelve specimens were studied. A 7.5-cm STA graft was obtained starting 1.5 cm below the zygomatic arch. The calibers of STA were measured. After a pterional craniotomy, the IMA was isolated inside the infratemporal fossa through a craniectomy within the lateral triangle (lateral to the posterolateral triangle) in the middle fossa and transposed for proximal end-to-end anastomosis to the STA. The Sylvian fissure was split exposing the insular segment of the MCA, and an STA-M2 end-to-side anastomosis was completed. Finally, the length of graft vessel was measured. Average diameters of the proximal and distal STA ends were 2.3 ± 0.2 and 2.0 ± 0.1 mm, respectively. At the anastomosis site, the diameter of the IMA was 2.4 ± 0.6 mm, and the MCA diameter was 2.3 ± 0.3 mm. The length of STA graft required was 56.0 ± 5.9 mm. The STA can be used as an interposition graft for high-flow IMA-MCA bypass if the STA is obtained 1.5 cm below the zygomatic arch and the IMA is harvested through the proposed approach. This procedure may provide an efficient and less invasive alternative for high-flow EC-IC bypass.

Surgical treatment of distal extracranial internal carotid artery aneurysms associated with pathological artery kinking

Extracranial internal carotid artery (ICA) aneurysms located at the entrance of the skull are a rare pathology. Surgical treatment is indicated for this pathology because of the risk of arterio-arterial embolism and the development of cerebrovascular disease. The domestic and international literature reports single cases or small group cases of successful surgical treatment of patients with distal internal carotid artery aneurysms associated with pathological kinking of the artery. Open surgery for aneurysms of this localization is complicated because of a high injury risk associated with the approach. Endovascular interventions are not always possible due to the presence of degenerative changes in the vascular wall and pathological artery kinking. We propose a surgical option for creating a high-flow ec-ic bypass between the external carotid artery and the M2 segment of the middle cerebral artery. The article describes the results of successful application of this technique in three patients with distal extracranial internal carotid artery aneurysms associated with pathological kinking of the artery.

Measuring competence development for performing high flow extracranial-to-intracranial bypass

We report our experience with competence development in the performance of high flow extracranial-to-intracranial (HF EC–IC) bypass surgery because of the infrequency of, and hence potential exposure to, this challenging surgery. We reviewed the National Hospital Morbidity Database for the incidence of EC-IC bypass surgery as well as a prospectively collected database (institutional experience). The following were recorded from the institutional experience: graft occlusion, stenosis, disruption, distal ischaemia, surgical complications of the bypass leading to a modified Rankin Scale (mRS) score >2, and intraoperative cross-clamping time. The cross-clamping time was considered the total time that circulation may have been impaired, which included both the distal and proximal cross-clamping periods. The Australian national EC–IC bypass rate (of all bypass types) averaged 1.9 cases per 1,000,000 head of population annually. The institutional experience (170 cases) of high flow EC–IC bypass in this series was associated with 14.7% (95% confidence interval [CI] 10.1-20.9) of graft complications. Graft-specific complications leading to a mRS score >2 were 5.9% (95% CI 3.1-10.6). For the 83 patients where the cross-clamping time was known, the time of cross-clamping was 44±14min. We concluded that HF EC–IC bypasses are rarely performed procedures that challenge the development of surgical competence. Novel ways of developing and maintaining surgical skills are necessary, including simulation and laboratory experience.

Endoscopic radial artery harvesting for U-clip high-flow EC-IC bypass

Bypass and aneurysm trapping constitute a well-known surgical solution for aneurysms that are not suitable for clipping or coiling. New techniques are available that make EC-IC bypass procedures easier, safer and, possibly, less invasive. The nitinol self-closing U-Clip device (Medtronic, Inc., Minneapolis) has been designed to facilitate the interrupted suture technique by eliminating the need for suture management, knot tying, and surgical assistance. We present two consecutive U-clip bypass procedures in which the radial artery graft was harvested endoscopically. This novel bypass technique employs endoscopy to minimise arm injury due to radial artery harvesting and self-closing U-clips to simplify the intracranial micro-anastomosis and reduce the temporary occlusion time. Angiography confirmed bypass patency in all patients. Combined with the innovative use of U-clips, these two examples illustrate how new technologies can simplify EC-IC bypass surgery while yielding a better cosmetic and functional outcome.

内頚動脈系非分岐部動脈瘤の治療

We experienced 5 cases of nonbranching site aneurysms arising from the internal carotid artery system in the past 5 years. Two cases were successfully treated with neck clipping and 2 cases were treated with trapping. Wrapping by gauze and fibrin glue was used in 1 unruptured case. The outcome was good in all cases (mRS 0-2). However, non-branching site aneurysms have fragile walls, the neck is not clearly defined and postoperative rebleeding can easily occur. We believe the sacrifice of a normal parent artery is necessary to prevent re-bleeding. For this reason, we believe interception of the parent artery should always be considered to prevent postoperative rebleeding. When parent artery interception is of concern regarding postoperative ischemic events, a high-flow EC-IC bypass may be needed. On the other hand, the issue of separation of the neck is possible at all sides and the possibility of clipping strangling part of the parent artery also exists.

Alternative vascular graft for extracranial–intracranial bypass surgery: descending branch of the lateral circumflex femoral artery

Arterial bypass is an important method of treating intracranial disease requiring sacrifice of the parent vessel. The conduits for extracranial-intracranial (EC-IC) bypass surgery include the superficial temporal artery, occipital artery, superior thyroid artery, radial artery, and saphenous vein (long or short). In an aging population with an increased prevalence of vascular disease, conduits for EC-IC bypass may be in short supply in some patients. Herein, the authors describe a case in which the descending branch of the lateral circumflex femoral artery (DLCFA) was utilized as a high-flow conduit for an EC-IC bypass. This 22-year-old woman presented with irregular menstrual periods, secondary amenorrhea, and hypothyroidism. A giant intrasellar and suprasellar mass was found. Angiography confirmed a 3.5 x 2.1-cm fusiform aneurysm involving the cavernous and supraclinoid segments of the right internal carotid artery. A suitable radial artery conduit was not available. The DLCFA was harvested and anastomosed between the M(2) segment of the middle cerebral artery and the external carotid artery. Durable clinical and angiographic results were apparent at the 2-month follow-up. The DLCFA's diameter and length were used successfully in a high-flow EC-IC bypass surgery. The DLCFA may be a good alternative to radial artery and saphenous vein grafts for an EC-IC bypass requiring high flow.

Long term evaluation of brain perfusion with magnetic resonance in high flow extracranial-intracranial saphenous graft bypass

Assessment was made of the cerebral vascular haemodynamic parameters in patients with a high-flow extra-intracranial (EC-IC) bypass performed for therapeutic occlusion of the internal carotid artery (ICA). Sixteen patients with ICA occlusion and EC-IC bypass (time interval from surgery 1-6 years) underwent MRI. Perfusion-weighted magnetic resonance imaging (PW-MRI) sequences were performed without the use of an arterial input function. The relative cerebral blood volume (rCBV), mean transit time (MTT) and relative cerebral blood flow (rCBF) were evaluated in all patients at the level of the basal ganglia, centrum semiovale and cortex in both hemispheres. Statistically significant differences (P<0.005) were observed in the haemodynamic parameters, indicating increased rCBV in the basal ganglia and decreased rCBF and rCBV in the cortex of the hemisphere supplied by the graft with respect to the contralateral. Patients with occlusion of the ICA and high flow EC-IC bypass do have altered vascular haemodynamic status between the hemispheres. In particular, rCBF is impaired in the surgical hemisphere at the level of the cortex. These patients should be followed-up to rule out chronic ischemia.

Flow quantification of the non-occlusive excimer laser-assisted EC-IC bypass.

For six years, we used the Excimer laser-assisted nonocclusive anastomosis technique for high-flow revascularization of the brain in patients with either nonclippable and noncoilable giant aneurysms of the internal carotid or basilar artery or progressive stroke associated with occlusive disease of the internal carotid artery. The aim of this study is to assess the blood flow capacity of this type of Extra-Intracranial bypass and its haemodynamic behaviour over time. Twenty-six patients with a giant aneurysms and 8 patients with occlusive disease of the internal carotid artery were treated with the nonocclusive Excimer laser assisted EC-IC bypass. intra-operatively, direct measurements of flow in the EC-IC bypass were performed in all patients (Transonic Systems, Inc., Ithaca. NY). Postoperatively, follow up measurements of flow were performed with MR angiography in 14 patients with a giant aneurysm after occluding the internal carotid artery, and 7 patients with occlusive carotid disease. The mean flow in the laser assisted bypasses in the group of patients with a giant aneurysm was 158 ml/min after ligation or balloon occlusion of the ICA. The mean flow of the laser assisted bypass in the group of patients with ICA occlusive disease was 130 ml/min. A comparison with data on flow capacity of conventional EC IC bypasses is made. A demonstrated increase of flow in the bypass during follow up is discussed from a haemodynamic point of view. The results of this study demonstrate that the flow capacity of the nonoccluding excimer laser assisted bypass is much higher than the capacity of the conventional, more peripherally located conventional EC IC bypass, and should therefore be denoted as High-Flow EC IC bypass. Consequently, this type of bypass can be a powerful and safe tool in new revascularization strategies.

未破裂脳動脈瘤

The indication of radical surgery for unruptured cerebral aneurysms (uAN) remains obscure. To prevent bleeding, we have aggressively performed radical surgery for uAN even in elderly patients (over 70 years old) and in patients with cerebral ischemia, with concurrent bypass surgery for ischemic patients if necessary. We evaluated our surgical strategy in this study by analyzing the results of patients, especially the ratio of surgical mortality/morbidity and its causes.Ninety-six patients (141 aneurysms) were treated. In 34 patients, aneurysms had been diagnosed without neurological symptoms. The remaining patients had been diagnosed at the examination due to precedent neurological diseases: subarachnoid hemorrhage (28 patients), hypertensive intracerebral hemorrhage (12), cerebral infarction (10), and the others (12). Distribution of the aneurysms were 57 internal carotid artery, 48 middle cerebral artery, 11 anterior cerebral artery, 10 anterior communicating artery, 8 basilar artery, 4 vertebral artery, and 2 posterior cerebral artery. Of the 141 aneurysms, 133 were clipped, and one was wrapped. Ligation or trapping of internal carotid artery with high flow EC-IC bypass using saphenous vein graft was done on 7 giant internal carotid aneurysms or symptomatic cavernous internal carotid aneurysms. Surgical mortality was 0 and morbidity was 5 cases (5.2%). Inappropriate handling of spatula and resultant cerebral contusion worsened the result of Case 1. Optic nerve compression with oxycellulose at dural repair after Dolenc approach caused ipsilateral blindness in Case 2. The cause of these morbidity was obviously carelessness. However, there was no apparent causal factor found in the following three cases (3, 4, 5). The three cases had common features as follows: 1) relatively high age (64, 67, 79 years old), 2) IC aneurysms, 3) large aneurysms, 4) not parent artery occlusion/stenosis but perforator injury suspected. One of the 3 patients received reoperation soon after the paresis had presented. But the clip was well placed, parent vessels were patent, and perforators looked healthy. Angiography of the remaining 2 cases showed no remarkable abnormality. Therefore, we cannot explain the neurological deficits in these cases.Good results were obtained with our strategy. Precedent neurological diseases may not influence the result, even cerebral ischemia if precise and careful preparation is performed. Concurrent bypass surgery may not be avoided. Care should be taken for elderly patients with IC large aneurysms because perforator injury by unknown causes occasionally occurs.

脳動脈瘤手術における STA-MCA 吻合部を介した脳表血圧モニターの有用性

For surgery of giant or large cerebral aneurysm, we have used the intraoperative monitoring of cortical blood pressure to safely perform surgery and to get optimal clipping, when the risk of parent arteries stenosis caused by aneurysmal clipping may be higher. We report the merits and demerits of this method compared with usual methods for CBF monitoring such as ultrasonic Doppler flowmeter.We studied 5 giant aneurysms and 3 large aneurysms by applying this method. In the 3 cases of giant aneurysm, high flow EC-IC bypass using radial artery (RA) free graft and ICA proximal ligation was performed. And in the other 2 cases, direct aneurysmal clipping under a temporary use of RA was employed. On the other hand, all 3 cases of large aneurysm had atheroscrelotic change in its wall. They were treated by direct clipping.To monitor the cortical blood pressure, the following procedure was used. At first, we prepared two branches of superficial temporal artery (STA). After this, one of the branches was anastomosed to one of the branches of the middle cerebral artery (MCA) just distal to the aneurysm. Next, cannulation was performed into another branches of STA using a plastic needle, which was connected to a pressure transducer. By cutting off the blood flow from the main trunk of the STA, cortical blood pressure of the MCA was monitored through the bypass pathway.Our study shows the differences between the two types of cases. In cases of direct clipping surgery, the change of cortical blood pressure indicated whether the parent artery was stenotic or not. And in cases of performing RA free graft bypass, it showed whether bypass flow could be used as a substitute for ICA flow or not. These results show it is easy to evaluate the direct blood pressure quantitively. In conclusion, this monitoring is considered a useful method to ensure safe surgery for patients with giant or large aneurysms.

Postsurgical observations of mean hemispheric cerebral blood flow with patients receiving high-flow EC-IC bypass using a radial artery graft: (preliminary report, one-year observation of 10 hemispheres)

BACKGROUND When we encounter an inaccessible internal carotid artery lesion, we sacrifice the inaccessible internal carotid artery and, at the same time, establish a high-flow extracranial-to-intracranial arterial bypass (EC-IC bypass). Questions and concerns remain, however, about the dynamics of the patient's cerebral blood flow postoperatively. METHOD Ten hemispheres from 9 patients had received radial artery grafting as an EC-IC bypass with the simultaneous obstruction of the internal carotid artery. Their mean hemispheric cerebral blood flow (mCBF) was measured longitudinally during 1 year after surgery by single photon emission computed tomography (SPECT) and a 133Xenon-inhalation method. RESULTS The serial mCBF values of the five hemispheres with giant aneurysm or paracavernous meningioma were attenuated during the postoperative 3-month period and then returned to the normal range. In only one case did the postoperative reduction of mCBF fail to return to normal; in addition there was a memory disturbance that had developed and progressed. Five hemispheres with the ICA stenosis did not present reduction in mCBF. In three out of five hemispheres, transient elevation of mCBF at 1 month after surgery was observed. CONCLUSIONS We conclude from our study that the internal carotid artery can be safely substituted by the radial artery graft from the view point of cerebral blood flow.