[EC-IC bypass for occlusion of the internal carotid artery]

BACKGROUND

There are barely any alternative treatment options to the drug treatment of hemodynamically caused cerebral ischemia, as in occlusion of the internal carotid artery.

OBJECTIVE

For secondary prevention of an ischemic stroke due to carotid occlusion and hemodynamic instability, extracranial-intracranial (EC-IC) bypass surgery can be an important option in selected patients.

MATERIAL AND METHODS

The development, study situation, indications and surgical technique for placement of an EC-IC bypass in cases of occlusion of the internal carotid artery are presented.

RESULTS

With appropriate expertise and strict selection of patients, the placement of an EC-IC bypass enables stabilization of cerebral perfusion with a low rate of complications.

CONCLUSION

The study situation is controversially discussed; nevertheless, surgical treatment in a specialized neurovascular center should at least be considered.

Staged Common and External Carotid Artery Stenting Followed by Superficial Temporal Artery to Middle Cerebral Artery Bypass

Superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery for internal carotid artery (ICA) occlusive disease necessarily requires sufficient external carotid artery (ECA) blood flow. Surgical bypass is therefore precluded if there is common carotid artery (CCA) occlusion. Here we present two such cases: one patient had a CCA occlusion and the other had an ICA occlusion and ECA stenosis. Both had failed medical management, and were therefore treated with angioplasty and stenting of the ECA, followed by STA-MCA bypass. We describe the clinical and radiologic outcomes of these cases, and remark on the potential pitfalls associated with this novel approach.

Surgical Outcomes of Low-Flow Bypass Surgery in Intracranial Atherosclerotic Steno-Occlusive Diseases

BACKGROUND AND OBJECTIVES

The role of bypass surgery in intracranial atherosclerotic steno-occlusive diseases (ICADs) remains controversial. We aimed to analyze the surgical outcomes of bypass surgery in patients with the ICADs in a single tertiary institution.

METHODS

Among 1018 cases of low-flow bypass surgery between 2003 and 2022, 215 patients with the ICAD refractory to medical treatment were finally enrolled in this study. Clinical and radiological outcomes were retrospectively evaluated, with survival analyses.

RESULTS

All strokes, cerebral infarctions, and intracranial hemorrhages occurred in 12.1% (n = 26), 9.8% (n = 21), and 2.3% (n = 5), respectively, during the clinical follow-up of 54.6 ± 47.6 months (range, 0.6-237.8 months). Among all stroke events, 84.6% (n = 22) occurred within 30 postoperative days. The 2-year and 5-year cumulative risks of all strokes were 12.1% each. The mean modified Rankin Scale scores were 1.6 ± 1.1 (range, 0-5) preoperatively and 0.8 ± 1.2 (range, 0-6) at last (P < .01). The patency of direct bypass was 99.1% (n = 213) just before discharge and 96.3% (n = 184 of 191 patients with available tests) at the last angiographic follow-up of 27.0 ± 27.3 months (range, 2.3-97.3 months). All the patients with available data (n = 190) showed hemodynamic improvement on acetazolamide-challenged single-photon emission computed tomography with 99mTc-hexamethylpropyleneamine oxime during the follow-up of 38.6 ± 36.7 months (range, 2.3-158.6 months).

CONCLUSION

Low-flow bypass surgery showed acceptable treatment outcomes in the prevention of recurrent stroke.

Extracranial-Intracranial Bypass and Risk of Stroke and Death in Patients With Symptomatic Artery Occlusion: The CMOSS Randomized Clinical Trial

Importance

Prior trials of extracranial-intracranial (EC-IC) bypass surgery showed no benefit for stroke prevention in patients with atherosclerotic occlusion of the internal carotid artery (ICA) or middle cerebral artery (MCA), but there have been subsequent improvements in surgical techniques and patient selection.

Objective

To evaluate EC-IC bypass surgery in symptomatic patients with atherosclerotic occlusion of the ICA or MCA, using refined patient and operator selection.

Design, Setting, and Participants

This was a randomized, open-label, outcome assessor-blinded trial conducted at 13 centers in China. A total of 324 patients with ICA or MCA occlusion with transient ischemic attack or nondisabling ischemic stroke attributed to hemodynamic insufficiency based on computed tomography perfusion imaging were recruited between June 2013 and March 2018 (final follow-up: March 18, 2020).

Interventions

EC-IC bypass surgery plus medical therapy (surgical group; n = 161) or medical therapy alone (medical group; n = 163). Medical therapy included antiplatelet therapy and stroke risk factor control.

Main Outcomes and Measures

The primary outcome was a composite of stroke or death within 30 days or ipsilateral ischemic stroke beyond 30 days through 2 years after randomization. There were 9 secondary outcomes, including any stroke or death within 2 years and fatal stroke within 2 years.

Results

Among 330 patients who were enrolled, 324 patients were confirmed eligible (median age, 52.7 years; 257 men [79.3%]) and 309 (95.4%) completed the trial. For the surgical group vs medical group, no significant difference was found for the composite primary outcome (8.6% [13/151] vs 12.3% [19/155]; incidence difference, -3.6% [95% CI, -10.1% to 2.9%]; hazard ratio [HR], 0.71 [95% CI, 0.33-1.54]; P = .39). The 30-day risk of stroke or death was 6.2% (10/161) in the surgical group and 1.8% (3/163) in the medical group, and the risk of ipsilateral ischemic stroke beyond 30 days through 2 years was 2.0% (3/151) and 10.3% (16/155), respectively. Of the 9 prespecified secondary end points, none showed a significant difference including any stroke or death within 2 years (9.9% [15/152] vs 15.3% [24/157]; incidence difference, -5.4% [95% CI, -12.5% to 1.7%]; HR, 0.69 [95% CI, 0.34-1.39]; P = .30) and fatal stroke within 2 years (2.0% [3/150] vs 0% [0/153]; incidence difference, 1.9% [95% CI, -0.2% to 4.0%]; P = .08).

Conclusions and Relevance

Among patients with symptomatic ICA or MCA occlusion and hemodynamic insufficiency, the addition of bypass surgery to medical therapy did not significantly change the risk of the composite outcome of stroke or death within 30 days or ipsilateral ischemic stroke beyond 30 days through 2 years.

Trial Registration

ClinicalTrials.gov Identifier: NCT01758614.

Clinical Analysis of Microvascular Reconstruction Combined With Decompressive Craniectomy in Patients With Malignant Middle Cerebral Artery Infarctions

PURPOSE

This study aimed to evaluate the safety and efficacy of microvascular reconstruction combined with decompressive craniectomy (DHC) in patients with malignant middle cerebral artery infarctions (MMCA).

METHODS

We searched for patients with MMCA and aged＜60 years old, postoperative survival of more than 3 months, consistent with decompression of bone flap removal. Patients were divided into experimental group and control group according to whether they underwent emergency vascular revascularization within 5 days after onset of ischemic stroke.

RESULTS

A total of sixpatients were included in the treatment group and 12 patients in the control group. The National Institutes of Health Stroke Scale (NIHSS) score of the treatment group was lower than that of the control group seven days after operation, but the difference was not statistically significant; 3 months after surgery, modified ranking scale (mRs) score in the treatment group was lower than that in the control group, the difference was statistically significant (P = 0.002); mRs scores of the treatment group 3 months after surgery were significantly different from those before surgery (P < 0.05), but no such difference was found in the control group.

CONCLUSION

Compared with decompressive craniectomy, open surgical revascularization can improve early cerebral perfusion in MMCA patients, and neurological recovery is better at 3 months after operation. By ensuring that surgeons are properly trained and hospitals are equipped, open surgical revascularization can be a treatment option for patients with MMCA.

Long-term outcomes and quantitative radiologic analysis of extracranial-intracranial bypass for hemodynamically compromised chronic large artery occlusive disease

This study aimed to demonstrate the effectiveness of nonemergent extracranial-to-intracranial bypass (EIB) in symptomatic chronic large artery atherosclerotic stenosis or occlusive disease (LAA) through quantitative analysis of computed tomography perfusion (CTP) parameters using RAPID software. We retrospectively analyzed 86 patients who underwent nonemergent EIB due to symptomatic chronic LAA. CTP data obtained preoperatively, immediately postoperatively (PostOp0), and 6 months postoperatively (PostOp6M) after EIB were quantitatively analyzed through RAPID software, and their association with intraoperative bypass flow (BF) was assessed. The clinical outcomes, including neurologic state, incidence of recurrent infarction and complications, were also analyzed. The time-to-maximum (Tmax) > 8 s, > 6 s and > 4 s volumes decreased significantly at PostOp0 and up through PostOp6M (preoperative, 5, 51, and 223 ml (median), respectively; PostOp0, 0, 20.25, and 143 ml, respectively; PostOp6M, 0, 7.5, and 148.5 ml, respectively; p < 0.001, p < 0.001, and p < 0.001, respectively). The postoperative improvement in the Tmax > 6 s and > 4 s volumes was significantly correlated with the BF at PostOp0 and PostOp6M (PostOp0, r = 0.367 (p = 0.001) and r = 0.275 (p = 0.015), respectively; PostOp6M r = 0.511 (p < 0.001) and r = 0.391 (p = 0.001), respectively). The incidence of recurrent cerebral infarction was 4.7%, and there were no major complications that produced permanent neurological impairment. Nonemergent EIB under strict operation indications can be a feasible treatment for symptomatic, hemodynamically compromised LAA patients.

Revisiting flow augmentation bypass for cerebrovascular atherosclerotic vaso-occlusive disease: Single-surgeon series and review of the literature

OBJECTIVE

Despite advances in the nonsurgical management of cerebrovascular atherosclerotic steno-occlusive disease, approximately 15-20% of patients remain at high risk for recurrent ischemia. The benefit of revascularization with flow augmentation bypass has been demonstrated in studies of Moyamoya vasculopathy. Unfortunately, there are mixed results for the use of flow augmentation in atherosclerotic cerebrovascular disease. We conducted a study to examine the efficacy and long term outcomes of superficial temporal artery to middle cerebral artery (STA-MCA) bypass in patients with recurrent ischemia despite optimal medical management.

METHODS

A single-institution retrospective review of patients receiving flow augmentation bypass from 2013-2021 was conducted. Patients with non-Moyamoya vaso-occlusive disease (VOD) who had continued ischemic symptoms or strokes despite best medical management were included. The primary outcome was time to post-operative stroke. Time from cerebrovascular accident to surgery, complications, imaging results, and modified Rankin Scale (mRS) scores were aggregated.

RESULTS

Twenty patients met inclusion criteria. The median time from cerebrovascular accident to surgery was 87 (28-105.0) days. Only one patient (5%) had a stroke at 66 days post-op. One (5%) patient had a post-operative scalp infection, while 3 (15%) developed post-operative seizures. All 20 (100%) bypasses remained patent at follow-up. The median mRS score at follow up was significantly improved from presentation from 2.5 (1-3) to 1 (0-2), P = .013.

CONCLUSIONS

For patients with high-risk non-Moyamoya VOD who have failed optimal medical therapy, contemporary approaches to flow augmentation with STA-MCA bypass may prevent future ischemic events with a low complication rate.

Spotlight on clinical strategies of Chronic Internal Carotid Artery Occlusion: Endovascular interventions and external-intracarotid bypasses compared to conservative treatment

Chronic internal carotid artery occlusion (CICAO) has high prevalence and incidence rates, and patients with CICAO can be completely asymptomatic, experience a devastating stroke or die. It is important to note that CICAO causes cerebrovascular accidents. Currently, the external carotid-internal carotid (EC-IC) bypass technique is used to treat CICAO. However, many clinical studies showed that EC-IC bypass was not beneficial for many patients with CICAO. Meanwhile, endovascular intervention treatment options for CICAO are evolving, and an increasing number of patients are undergoing endovascular intervention therapy. Accordingly, a review comparing both techniques is warranted. For this review, we searched PubMed and collected relevant case study reports comparing endovascular interventional therapy and internal and external cervical bypass surgeries to provide strategies for clinical treatment.

Quantitative radiological analysis and clinical outcomes of urgent EC-IC bypass for hemodynamic compromised patients with acute ischemic stroke

This study aimed to demonstrate the effectiveness of urgent extracranial-to-intracranial bypass (EIB) in acute ischemic stroke (AIS) through quantitative analysis of computed tomography perfusion (CTP) results using RAPID software. We retrospectively analyzed 41 patients who underwent urgent EIB for AIS under strict operation criteria. The quantitative data from CTP images were reconstructed to analyze changes in pre- and postoperative perfusion status in terms of objective numerical values using RAPID software. Short- and long-term clinical outcomes, including complications and neurological status, were also analyzed. Postoperatively, the volume of time-to-max (Tmax) > 6 s decreased significantly; it continued to improve significantly until 6 months postoperatively (preoperative, 78 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 7 ml; p = 0.000). Ischemic core-penumbra mismatch volumes were also significantly improved until 6 months postoperatively (preoperative, 72 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 5 ml; p = 0.000). In addition, the patients' neurological condition improved significantly (p < 0.001). Only one patient (2.3%) showed progression of infarction. Urgent EIB using strict indications can be a feasible treatment for IAT-ineligible patients with AIS due to large vessel occlusion or stenosis.

Cross-Comparison of 4-Dimensional Flow Magnetic Resonance Imaging and Intraoperative Middle Cerebral Artery Pressure Measurements Before and After Superficial Temporal Artery-Middle Cerebral Artery Bypass Surgery

BACKGROUND

The hemodynamic changes after superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery are unclear.

OBJECTIVE

To clarify the hemodynamics by comparing flow parameters obtained by 4-dimensional (4D) flow magnetic resonance imaging (MRI) and intraoperative MCA pressure measurement.

METHODS

We recruited 23 patients who underwent STA-MCA bypass surgery for internal carotid artery (ICA) or MCA stenosis. We monitored intraoperative MCA, STA, and radial artery (RA) pressure. All patients underwent 4D flow MRI preoperatively and 3 wk after surgery to quantify the blood flow volume (BFV) of the ipsilateral ICA (BFViICA), contralateral ICA (BFVcICA), basilar artery (BFVBA), ipsilateral STA (BFViSTA), and contralateral STA (BFVcSTA). The sum of intracranial BFV was defined as BFVtotal. We compared BFV parameters and intraoperative pressure.

RESULTS

BFViSTA significantly increased after surgery (P < .001). BFViICA and BFVBA significantly decreased after surgery (BFViICAP = .005; BFVBAP = .02). No significant difference was observed between BFVcICA before and after surgery. As a result, BFVtotal postoperatively increased by 6.8%; however, no significant difference was observed. Flow direction at M1 changed from antegrade to unclear after surgery in 5 patients. Intraoperative MCA pressure and MCA/RA pressure ratio significantly increased after surgery (P < .001). We found a stronger positive correlation between MCA pressure increase ratio and BFVtotal increase ratio in patients with lower pre-MCA pressure (r = 0.907, P < .001).

CONCLUSION

The visual and quantitative assessment of 4D flow MRI revealed that intracranial blood flow changes complementarily after STA-MCA bypass surgery. 4D flow MRI may detect the improvement of cerebral perfusion pressure.

Patients Receiving Extracranial to Intracranial Bypass for Atherosclerotic Vessel Occlusion Today Differ Significantly From the COSS Population

[Figure: see text].

Superficial Temporal Artery to Middle Cerebral Artery Cranial Bypass for Nonmoyamoya Steno-Occlusive Disease in Patients Who Failed Optimal Medical Treatment: A Case Series

BACKGROUND

In the post-Carotid Occlusion Surgery Study (COSS) era, multiple reviews suggested subset groups of patients as potential candidates for superficial temporal artery to middle cerebral artery (STA-MCA) bypass. Among them are patients with recurrent strokes despite optimal medical therapy. There is a paucity of data on the outcome of bypass in these specific patients.

OBJECTIVE

To examine the safety and efficacy of direct STA-MCA bypass in patients with nonmoyamoya, symptomatic steno-occlusive disease with impaired distal perfusion, who failed optimal medical management or endovascular treatment.

METHODS

A retrospective review was performed to identify patients with cerebrovascular steno-occlusive disease who underwent bypass after symptomatic recurrent or rapidly progressive strokes, despite optimal conservative or endovascular treatment.

RESULTS

A total of 8 patients (mean age 60 ± 6 yr) underwent direct or combined direct/indirect STA-MCA bypass between 2016 and 2019. All anastomoses were patent. One bypass carried slow flow. There were no procedure-related permanent deficits. One patient developed seizures which were controlled by medications. A total of 7 out of 8 patients were stable or improved clinically at last follow-up (mean 27.3 ± 13.8 mo) without recurrent strokes. One patient did not recover from their presenting stroke, experienced severe bilateral strokes 4 mo postoperatively, and subsequently expired. Modified Rankin Scale (mRS) improved in 6 patients (75%), remained stable in 1 patient (12.5%), and deteriorated in 1 (12.5%). Good long-term functional outcome was achieved in 5 patients (63%, mRS ≤ 2).

CONCLUSION

Patients with symptomatic, hypoperfused steno-occlusive disease who fail optimal medical or endovascular treatment may benefit from cerebral revascularization. Direct or combined STA-MCA bypass was safe and provided favorable outcomes in this small series.

Impact of Extracranial-Intracranial Bypass on Cognitive Function in a Patient with Chronic Cerebral Ischemia

Extracranial–intracranial (EC-IC) arterial bypass surgery was developed to prevent subsequent stroke by improving hemodynamics distal to the occluded intracranial artery, but its utilization has been decreasing due to the development in medical treatment. However, EC-IC bypass surgery may be effective for arresting or reversing cognitive decline in patients with cerebral ischemia. A 69-year-old man with the left internal carotid artery occlusion that manifested as scattered cerebral infarction of the left hemisphere presented with dysarthria and transient right hemiparesis. Hemodynamic condition was impaired in the left side, and therefore, EC-IC bypass surgery was performed to prevent recurrence of cerebral infarction. Neuropsychological examination at 6 months after the surgery showed marked improvement as compared to the preoperative examination and there was no recurrence of stroke in the patient. EC-IC bypass may contribute to the improvement of cognitive function as well as the prevention of recurrence of cerebral infarction in patients with hemodynamic insufficiency, but there might be a threshold of hemodynamic impairment with respect to the reversibility of cognitive performance. Investigation of the target and timing can identify cases in which the cognitive function is improved by surgery.

Subclavian Artery to Internal Carotid Artery Interpositional Bypass for Carotid Artery Occlusion: Technical Case Report

BACKGROUND AND IMPORTANCE

Conventional microsurgical treatment for symptomatic internal carotid artery (ICA) occlusion is revascularization with superficial temporal artery (STA) to middle cerebral artery bypass. However, in rare cases where the common carotid artery, external carotid artery (ECA), or both are also occluded, other microsurgical treatment options must be considered.

CLINICAL PRESENTATION

We present the case of a 52-yr-old woman with common carotid artery occlusion and weak ICA flow from collateral connections between the vertebral artery, occipital artery, and ECA. She had ischemic symptoms and a history of stroke. The patient's STA was unsuitable as a donor vessel due to its small caliber and poor flow, and we instead performed an interpositional bypass from the subclavian artery to the ICA using a radial artery graft.

CONCLUSION

This case illustrates the successful use of the subclavian artery to ICA bypass technique with an interpositional radial artery graft. The surgical anatomy of the subclavian arteries is reviewed, and the technical details of subclavian artery to radial artery graft to ICA interpositional bypass are presented.

Contemporary trends in extracranial-intracranial bypass utilization: analysis of data from 2008 to 2016

OBJECTIVE

The impact of FDA approval of flow-diversion technology for the treatment of supraclinoid internal carotid artery aneurysms and the publication of the Carotid Occlusion Surgery Study, both of which occurred in 2011, on the utilization of extracranial-intracranial (EC-IC) bypasses is not known.

METHODS

The National Inpatient Sample (NIS) was queried for hospitalizations for EC-IC bypass performed from 2008 to 2016. Diagnoses of interest included an unruptured intracranial aneurysm (UIA), subarachnoid hemorrhage (SAH), carotid occlusive disease (COD), and moyamoya disease. The authors assessed trends in EC-IC bypass utilization for these diagnoses and the incidence of adverse discharges, defined as discharge to locations other than home, and the rate of mortality.

RESULTS

A total of 1640 EC-IC bypass procedures were performed at 558 hospitals during the study period, with 1148 procedures at 448 hospitals performed for a diagnosis of interest. The most frequent surgical indication was moyamoya disease (65.7%, n = 754), followed by COD (23.2%, n = 266), SAH (3.2%, n = 37), and a UIA (7.9%, n = 91). EC-IC bypass utilization for COD decreased from 0.21 per 100 admissions of COD in 2010 to 0.09 per 100 admissions in 2016 (p = 0.023). The frequency of adverse discharges increased during the study period from 22.3% of annual admissions in 2008 to 31.2% in 2016 (p = 0.030) when analysis was limited to procedures performed for a diagnosis of interest. Per volume, the top 5th percentile of hospitals, on average, performed 18.4 procedures (SD 13.2) per hospital during the study period, compared to 1.3 procedures (SD 1.3) that were performed in hospitals within the bottom 95th percentile. The rate of adverse discharges was higher at low-volume institutions when compared to that at high-volume institutions (33.8% vs 28.7%; p = 0.029). Over the study period, the authors noted a trend toward a reduced percentage of total surgical volume performed at high-volume hospitals (p < 0.001).

CONCLUSIONS

The authors observed a decrease in the utilization of EC-IC bypass for COD during the study period. An increase in the rate of adverse discharges was also noted, coinciding with more procedures being performed at lower-volume centers.

The cut flow index revisited: utility of intraoperative blood flow measurements in extracranial-intracranial bypass surgery for ischemic cerebrovascular disease

OBJECTIVE

In extracranial-intracranial (EC-IC) bypass surgery, the cut flow index (CFI) is the ratio of bypass flow (ml/min) to donor vessel cut flow (ml/min), and a CFI ≥ 0.5 has been shown to correlate with bypass patency. The authors sought to validate this observation in a large cohort of EC-IC bypasses for ischemic cerebrovascular disease with long-term angiographic follow-up.

METHODS

All intracranial bypass procedures performed at a single institution between 2003 and 2018 were reviewed. Demographic, clinical, angiographic, and operative data were recorded and analyzed according to bypass patency with univariate and multivariate statistical analyses.

RESULTS

A total of 278 consecutive intracranial bypasses were performed during the study period, of which 157 (56.5%) were EC-IC bypasses for ischemic cerebrovascular disease. Intraoperative blood flow measurements were available in 146 patients, and angiographic follow-up was available at a mean of 2.1 ± 2.6 years after bypass. The mean CFI was significantly higher in patients with patent bypasses (0.92 vs 0.64, p = 0.003). The bypass patency rate was 83.1% in cases with a CFI ≥ 0.5 compared with 46.4% in cases with a CFI < 0.5 (p < 0.0001). Adjusting for age, sex, diagnosis, and single versus double anastomosis, the CFI remained a significant predictor of bypass patency (p = 0.001; OR 5.8, 95% CI 2.0-19.0). A low CFI was also associated with early versus late bypass nonpatency (p = 0.008).

CONCLUSIONS

A favorable CFI portends long-term EC-IC bypass patency, while a poor CFI predicts eventual bypass nonpatency and can alert surgeons to potential problems with the donor vessel, anastomosis, or recipient bed during surgery.

Early versus Delayed Extracranial-Intracranial Bypass Surgery in Symptomatic Atherosclerotic Occlusion

BACKGROUND

Clinical trials of extracranial-intracranial (EC-IC) bypass surgery studied patients in subacute and chronic stage after ischemic event.

OBJECTIVE

To investigate the short-term outcomes of EC-IC bypass in progressive acute ischemic stroke or recent transient ischemic attacks.

METHODS

The study was a retrospective review at a single tertiary referral center from 2008 to 2015. Inclusion criteria consisted of EC-IC bypass within 1 yr of last ischemic symptoms ipsilateral to atherosclerotic occlusion of internal carotid or middle cerebral artery. Early bypass group who underwent surgery within 7 d of last ischemic symptoms were compared to late bypass group who underwent surgery >7 d from last ischemic symptom. The primary endpoint was perioperative ischemic or hemorrhagic stroke or intracranial hemorrhage within 7 d of surgery.

RESULTS

Of 126 patients who underwent EC-IC bypass during the period, 81 patients met inclusion criteria, 69 (85%) persons had carotid artery occlusion, 7 (9%) had proximal MCA occlusion, and 5 (6%) had both. Early surgery had a 31% (9/29) perioperative stroke rate compared to 11.5% (6/52) of patients undergoing late bypass (P = .04). Of patients with acute stroke within 7 d of surgery, 41% (7/17) had perioperative stroke within 7 d (P = .07). Six of nine patients (67%) with blood pressure dependent fluctuation of neurologic symptoms had perioperative stroke (P = .049).

CONCLUSION

EC-IC bypass in setting of acute symptomatic stroke within 1 wk may confer higher risk of perioperative stroke. Patients undergoing expedited or urgent bypass for unstable or fluctuating stroke symptoms might be at highest risk for perioperative stroke.

Balanced single-vector co-delivery of VEGF/PDGF-BB improves functional collateralization in chronic cerebral ischemia

The myoblast-mediated delivery of angiogenic genes represents a cell-based approach for targeted induction of therapeutic collateralization. Here, we tested the superiority of myoblast-mediated co-delivery of vascular endothelial growth factor-A (VEGF) together with platelet-derived growth factor-BB (PDGF-BB) on transpial collateralization of an indirect encephalomyosynangiosis (EMS) in a model of chronic cerebral ischemia. Mouse myoblasts expressing a reporter gene alone (empty vector), VEGF, PDGF-BB or VEGF and PDGF-BB through a single bi-cistronic vector (VIP) were implanted into the temporalis muscle of an EMS following permanent ipsilateral internal carotid artery occlusion in adult, male C57BL/6N mice. Over 84 days, myoblast engraftment and gene product expression, hemodynamic impairment, transpial collateralization, angiogenesis, pericyte recruitment and post-ischemic neuroprotection were assessed. By day 42, animals that received PDGF-BB in combination with VEGF (VIP) showed superior hemodynamic recovery, EMS collateralization and ischemic protection with improved pericyte recruitment around the parenchymal vessels and EMS collaterals. Also, supplementation of PDGF-BB resulted in a striking astrocytic activation with intrinsic VEGF mobilization in the cortex below the EMS. Our findings suggest that EMS surgery together with myoblast-mediated co-delivery of VEGF/PDGF-BB may have the potential to serve as a novel treatment strategy for augmentation of collateral flow in the chronically hypoperfused brain.

Revascularization surgery for symptomatic non-moyamoya intracranial arterial stenosis or occlusion

OBJECTIVE

Previous trials rejected a role of extracranial-to-intracranial bypass surgery for managing symptomatic atheromatous disease. However, hemodynamic insufficiency may still be a rationale for surgery, provided the bypass can be performed with low morbidity and patency is robust.

METHODS

Consecutive patients undergoing bypass surgery for symptomatic non-moyamoya intracranial arterial stenosis or occlusion were retrospectively identified. The clinical course and surgical outcomes of the cohort were evaluated at 6 weeks, 6 months, and annually thereafter.

RESULTS

From 1992 to 2017, 112 patients underwent 127 bypasses. The angiographic abnormality was arterial occlusion in 80% and stenosis in 20%. Procedures were performed to prevent future stroke (76%) and stroke reversal (24%), with revascularization using an arterial pedicle graft in 80% and venous interposition graft (VIG) in 20%. A poor outcome (bypass occlusion, new stroke, new neurological deficit, or worsening neurological deficit) occurred in 8.9% of patients, with arterial pedicle grafts (odds ratio [OR] 0.15), bypass for prophylaxis against future stroke (OR 0.11), or anterior circulation bypass (OR 0.17) identified as protective factors. Over the first 8 years following surgery the 66 cases exhibiting all three of these characteristics had minimal risk of a poor outcome (95% confidence interval 0%-6.6%).

CONCLUSIONS

Prophylactic arterial pedicle bypass surgery for anterior circulation ischemia is associated with high graft patency and low stroke and surgical complication rates. Higher risks are associated with acute procedures, typically for posterior circulation pathology and requiring VIGs. A carefully selected subgroup of individuals with hemodynamic insufficiency and ischemic symptoms is likely to benefit from cerebral revascularization surgery.

Encephaloduroarteriosynangiosis for hemorrhagic moyamoya disease: long-term outcome of a consecutive series of 95 adult patients from a single center

OBJECTIVE

The objective of this study was to investigate long-term outcomes after encephaloduroarteriosynangiosis (EDAS) for the treatment of hemorrhagic moyamoya disease (MMD) and identify the risk factors for recurrent hemorrhages.

METHODS

The authors retrospectively reviewed 95 patients with hemorrhagic MMD who were treated with EDAS at 307th Hospital PLA. Clinical features, angiographic findings, and clinical outcomes were investigated. Rebleeding incidences were compared between anterior or posterior hemorrhagic sites. Kaplan-Meier survival analysis and Cox proportional hazards regression models were used to estimate rebleeding risks after EDAS.

RESULTS

The average age at symptom onset was 37.1 years (range 20-54 years) for adult patients. The ratio of female to male patients was 1.16:1. In 61 of 95 hemorrhagic hemispheres (64.2%), the anterior choroidal artery (AChA) or posterior communicating artery (PCoA) was extremely dilated, with extensive branches beyond the choroidal fissure, which only occurred in 28 of 86 nonhemorrhagic hemispheres (32.6%). Fifty-seven incidences were classified as anterior hemorrhages and 38 as posterior. Sixteen of 95 patients (16.8%) suffered cerebral rebleeding after a median follow-up duration of 8.5 years. The annual rebleeding rate was 2.2% per person per year. The incidence rate was higher for the posterior group than for the anterior group, but this difference was not statistically significant (p > 0.05). Cox regression analysis revealed that the age of symptom onset (OR 1.075, 95% CI 1.008-1.147, p = 0.028) was a predictor of rebleeding strokes.

CONCLUSIONS

Through long-term follow up, EDAS proved beneficial for patients with hemorrhagic MMD. Dilation of the AChA-PCoA is associated with the initial hemorrhage of MMD, and rebleeding is age-related. Patients with hemorrhagic MMD should undergo follow-up over the course of their lives, even when neurological status is excellent.

Occipital artery-anterior cerebral artery bypass with posterior auricular artery-middle cerebral artery bypass for stenosis of the internal carotid artery bifurcation

Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass, and STA-anterior cerebral artery (ACA) bypass, are options for direct revascularisation of anterior circulation. However, some patients don't have a suitable STA to use as a donor, so an alternative procedure must be performed. A 59-year-old, right-handed man presented with dysphasia and right-sided hemiparesis due to a transient ischaemic attack. Imaging studies revealed severe stenosis of the left internal carotid artery bifurcation. Iodoamphetamine single photon emission computed tomography demonstrated reduced cerebrovascular reserve capacity in the left hemisphere. The patient was started on antiplatelet therapy, but the ischaemic attacks persisted after one month. Thus, revascularisation of the ACA and MCA territories was considered. Digital subtraction angiography revealed prominence in the left occipital artery (OA) and posterior auricular artery (PAA), while the left STA was hypoplastic, terminating at the squamous suture level. Therefore, anastomoses were performed between both the OA and ACA and the PAA and MCA. Revascularisation was successful, and the ischaemic attacks disappeared. OA-ACA bypass, together with PAA-MCA bypass, may be effective for wide cerebral revascularisation when the STA is not available.

Long-Term Effects on Preventing Stroke after Endovascular Treatment or Bypass Surgery for Intracranial Arterial Stenosis

BACKGROUND

Intracranial arterial stenosis (ICAS) is an important cause of ischemic stroke worldwide due to its higher risk of recurrence with medical therapy. Although some large randomized studies failed to show the superiority of surgical treatment compared with medical therapy, the results of medical therapy are not sufficient. There are patients who still benefit from surgical treatment. This retrospective analysis aimed to evaluate the long-term efficacy of surgical therapy with percutaneous transluminal angioplasty and/or stenting (PTA/PTAS) or extracranial-intracranial (EC/IC) bypass surgery for patients with ICAS.

METHODS

Between October 2005 and December 2016, 55 ICAS patients were treated with PTA/PTAS or EC-IC bypass surgery. Their electronic medical records were retrospectively reviewed and analyzed. The primary outcome was all adverse events beyond 30 days after a revascularization procedure.

RESULTS

We performed 21 cases (35%) of PTA, 4 cases (7%) of PTAS, and 34 cases (58%) of EC-IC bypass surgery and the median follow-up duration was 66 months (range 1-144 months). The occurrence rate of the primary outcome was 10.2% and only 1 patient (1.8%) experienced ipsilateral disabling ischemic stroke beyond 30 days. The long-term functional independent survival rate was 83.6%.

CONCLUSIONS

We demonstrated a long-term favorable outcome of combined surgical intervention for ICAS patients with PTA/PTAS and EC-IC bypass surgery, and the result was better than previously reported outcomes of medical therapy. Additional multicenter studies are required to draw firm conclusions on the efficacy of reduction of recurrent stroke in patients with ICAS.

STA-Distal ACA Bypass Using a Contralateral STA Interposition Graft for Symptomatic ACA Stenosis

Intracranial arterial stenosis usually occurs due to atherosclerosis and is considered the most common cause of stroke worldwide. Although the effectiveness of bypass surgery for ischemic stroke is controversial, the superficial temporal artery to the middle cerebral artery bypass for ischemic stroke is a common procedure. In our report, a 50-year-old man presented with sudden-onset left side weakness and dysarthria. An angiogram showed significant stenosis in the junction of the right cavernous-supraclinoid internal carotid artery and right pericallosal artery. Symptoms altered between improvement and deterioration. Magnetic resonance imaging showed a repeated progression of anterior cerebral artery (ACA) infarction despite maximal medical therapy. We performed a STA-ACA bypass with contralateral STA interposition. Postoperative course was uneventful with no further progression of symptoms. Thus, bypass surgery may be considered in patients with symptomatic stenosis or occlusion of the ACA, especially when patients present progressive symptoms despite maximal medical therapy.

[Revascularization experience and results in ischaemic cerebrovascular disease: Moyamoya disease and carotid occlusion]

INTRODUCTION

Cerebral revascularization techniques are an indispensable tool in the current armamentarium of vascular neurosurgeons. We present revascularization surgery experience and results in both moyamoya disease and occlusive cerebral ischaemia.

PATIENTS AND METHODS

Patients with ischaemic occlusive disease and moyamoya disease who underwent microsurgical revascularization between October 2014 and September 2017 were analysed.

RESULTS

In the study period, 23 patients with occlusive ischaemic disease underwent microsurgical revascularization. Three patients presented with serious postoperative complications (2 intraparenchymal haemorrhages in the immediate postoperative period and one thrombosis of the femoral artery). All patients, except one, achieved normalization of the cerebral hemodynamic reserve (CHR) in the SPECT study. Twenty patients had a good neurological result, with no ischaemic recurrence of the revascularized territory. Among patients with moyamoya, 20 had moyamoya disease and 5 had moyamoya syndrome with unilateral involvement. Five patients were treated at paediatric age. Haemorrhagic onset occurred in 2 patients. The CHR study showed hemodynamic compromise in all patients. Cerebral SPECT at one year showed resolution of the hemodynamic failure in all patients. There have been 4 postoperative complications (acute subdural hematoma, two subdural collections and one dehiscence of the surgical wound). No patient presented with neurological worsening at 6 and 12months of follow-up.

CONCLUSIONS

Cerebral revascularization through end-to-side anastomosis between the superficial temporal artery and a cortical branch of the middle cerebral artery is an indisputable technique in the treatment of moyamoya disease and possibly in a subgroup of patients with symptomatic occlusive ischaemic cerebrovascular disease.

The Value of the Middle Meningeal Artery in Cerebrovascular Bypass Surgery: An Anatomic Feasibility Study

BACKGROUND

Over the past decade, there has been a revival and a renewed interest for cerebrovascular bypass procedures. The superficial temporal artery (STA) has its value as a reliable donor vessel; however, a possible role for the middle meningeal artery (MMA) as a donor artery is still unclear.

OBJECTIVE

To assess the feasibility of using the MMA as a donor vessel in cerebrovascular surgery.

METHODS

We performed cadaveric dissections on 12 fresh specimens (23 sides) after bilateral silicone injection into the internal and external carotid arteries. We compared the size, diameter, and possibility to perform a bypass to the middle cerebral artery for both the MMA and the STA. Measurements were done using an electrical caliper. Additional measurements of the MMA and STA were performed on 20 random angiograms.

RESULTS

There was no statistically significant difference in diameter of the MMA at its ostium being 2.4 mm, compared to 2.7 mm for the STA ostium (t-test; P = .21). The MMA could be mobilized over 4.1 cm, whereas the STA over 8.3 cm. Finally, the mean diameter of the donor vessel at the site of the anastomosis was 1.6 mm versus 1.9 mm for MMA and STA, respectively (P = .0026). We were able to perform an MMA and middle cerebral artery anastomosis on 17 sides.

CONCLUSION

These results suggest that the MMA is a potentially valuable donor vessel to be used in selected cases. The availability of a suitable MMA branch should be assessed preoperatively on the angiogram.

The Carotid and Middle cerebral artery Occlusion Surgery Study (CMOSS): a study protocol for a randomised controlled trial

BACKGROUND

Patients with symptomatic internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion with haemodynamic insufficiency are at high risk for recurrent stroke when treated medically.

METHODS

The Carotid or Middle cerebral artery Occlusion Surgery Study (CMOSS) trial is an ongoing, government-funded, prospective, multicentre, randomised controlled trial. The CMOSS will recruit 330 patients with symptomatic ICA or MCA occlusion (parallel design, 1:1 allocation ratio) and haemodynamic insufficiency. Participants will be allocated to best medical treatment alone or best medicine plus extracranial-intracranial (EC-IC) bypass surgery. The primary outcome events are all strokes or deaths occurring between randomisation and 30 days post operation or post randomisation and ipsilateral ischaemic stroke within 2 years. Recruitment will be finished by December 2016. All the patients will be followed for at least 2 years. The trial is scheduled to complete in 2019.

DISCUSSION

The CMOSS will test the hypothesis that EC-IC bypass surgery plus best medical therapy reduces subsequent ipsilateral ischaemic stroke in patients with symptomatic ICA or MCA occlusion and haemodynamic cerebral ischaemia. This manuscript outlines the rationale and the design of the study. CMOSS will allow for more critical reappraisal of the EC-IC bypass for selected patients in China.

TRIAL REGISTRATION

NCT01758614 with ClinicalTrials.gov. Registered on 24 December 2012.

Effectiveness of Superficial Temporal Artery-to-Middle Cerebral Artery Anastomosis in Treating Moyamoya Disease by Reducing Endothelial Progenitor Cells

OBJECTIVE

To explore the effectiveness of superficial temporal artery-to-middle cerebral artery (STA-MCA) anastomosis in treating moyamoya disease (MMD).

METHODS

A total of 30 patients with MMD (hemorrhagic type, n = 13; ischemic type, n = 17) who had undergone STA-MCA anastomosis were enrolled in this study (anastomosis group). Cerebral blood flow was evaluated before and after surgery using cerebral angiography and computed tomography (CT) perfusion imaging. In addition, 27 patients with MMD (hemorrhagic type, n = 11; ischemic type, n = 16) who had received only conservative treatment were enrolled as the control group. Patients in both the anastomosis group and the control group were followed up for 5 years, and the incidences of cerebral hemorrhage and cerebral ischemia were analyzed. Blood samples were collected in both groups before and after treatment. Mononuclear cells were separated by density gradient centrifugation. After labeling with 3 direct fluorescent antibodies (CD133, CD34, and vascular endothelial growth factor receptor 2), the number of endothelial progenitor cells (EPCs) was detected using flow cytometry.

RESULTS

Cerebral blood flow was remarkably improved after STA-MCA anastomosis. The incidences of cerebral hemorrhage and cerebral ischemia were significantly lower in the anastomosis group than in the control group. The number of EPCs showed no significant change before and after treatment in the control group; in contrast, it was decreased significantly after surgery in the anastomosis group.

CONCLUSIONS

STA-MCA anastomosis can reduce the number of EPCs in MMD patients, lower the risk of rebreeding, and improve cerebral ischemic attacks.

Carotid bypass for carotid occlusion

The 2-year risk of ipsilateral ischemic stroke following internal carotid artery occlusion (ICAO) in a patient undergoing maximal medical therapy is 5-8% per year. While medical therapy may reduce the risk of stroke, it does not completely eliminate it. Since the 1985 extracranial-intracranial (EC-IC) bypass study, additional trials have been conducted to further investigate the usefulness of EC-IC bypass surgery in more selected patients with cerebral ischemia and impaired hemodynamic reserve. These important studies will be briefly reviewed in this article, as well as a discussion regarding the utility of bypass surgery for ICAO in current clinical practice. In addition, a short discussion regarding the pathophysiology of carotid occlusion will be presented. We will also highlight our own institutional patient selection criteria based on the latest methods for hemodynamic assessment, as well as our intraoperative flow assisted surgical techniques (FAST), and post-operative patient follow-up.

Emergent surgical embolectomy in conjunction with cervical internal carotid ligation and superficial temporal artery-middle cerebral artery bypass to treat acute tandem internal carotid and middle cerebral artery occlusion due to cervical internal carotid artery dissection

Background:

Acute tandem cervical dissecting internal carotid artery (ICA) occlusion and intracranial embolic middle cerebral artery (MCA) occlusion can be devastating, and the optimal treatment strategy for this condition has not been established yet.

Case Description:

A 45-year-old male presented with aphasia and right hemiparesis preceded by neck pain. Computed tomography showed a high-density signal along the left MCA, suggesting extensive emboli. Magnetic resonance angiography demonstrated tandem occlusion of the left cervical ICA and intracranial MCA with minimal diffusion-weighted imaging lesion. Emergent surgical embolectomy was performed, and long intracranial MCA emboli were retrieved with collateral cross-flow restoration. The cervical ICA was exposed, and dissection was confirmed. The cervical ICA was ligated, and superficial temporal artery (STA)-MCA anastomosis was added. Postoperatively, the patient demonstrated recovery from right hemiparesis and aphasia. At the 6^th postoperative month, follow-up studies demonstrated a robustly patent STA-MCA bypass and no additional ischemic lesion on T2-weighted imaging.

Conclusions:

Surgical embolectomy in conjunction with ligation of the cervical ICA followed by STA-MCA bypass might be a safe alternative method to endovascular recanalization, when the cervical dissection is extensive and when huge secondary emboli are present along the MCA.

Postoperative transient neurological symptoms and chronic subdural hematoma after extracranial-intracranial bypass for internal carotid/middle cerebral atherosclerotic steno-occlusive diseases: negative effect on cognitive performance

BACKGROUND

The mechanisms underlying post-extracranial to intracranial (EC-IC) bypass neurocognitive changes are poorly understood.

METHODS

Data from 55 patients who underwent a unilateral EC-IC bypass for atherosclerotic internal carotid artery (ICA)/middle cerebral artery (MCA) steno-occlusive disease were retrospectively evaluated. These patients underwent neuropsychological examinations (NPEs), including assessment by the Wechsler Adult Intelligence Scale-Third Edition and Wechsler Memory Scale-Revised (WMS-R) before and 6 months after EC-IC bypass. Results of NPEs were converted into Z-scores from which preoperative cognitive composite scores (CSpre) and postoperative cognitive composite scores (CSpost) were obtained. The association between the change of composite score between pre- and postoperative NPEs (CSpost-pre = CS post - CS pre) and various variables were assessed. These latter variables included occluded artery (ICA or MCA), preexisting ischemic lesion as verified in preoperative T2WI, robust bypass patency as verified by MRA performed approximately 6 months postoperatively, and postoperative transient neurological symptoms and/or postoperative chronic subdural hematoma (CSDH), both of which were dichotomized as postoperative events.

RESULTS

Postoperative MRI follow-up (median, 6 months; interquartile range, 5-8 months) confirmed successful bypasses in all patients, with no additional ischemic lesions on T2WI when compared with preoperative imaging. Further, MRA showed patent bypasses in all patients. A nearly statistically significant CS post-pre decrease was observed in patients with postoperative events when compared with those without postoperative events (-0.158 vs. 0.039; p = 0.069). A multiple regression model predicting CSpost-pre was performed. After controlling for occluded arteries, postoperative events were identified as an independent predictor of a decline in CSpost-pre (p = 0.044). In the group rate analysis, three of four postoperative NPE scores (Performance IQ, WMS-memory, WMS-attention) were significantly improved relative to preoperative NPE scores.

CONCLUSIONS

Postoperative transient neurological symptoms and/or CSDH might play a significant role in the subtle decline in cognition following an EC-IC bypass. However, this detrimental effect was small, and based on the group rate analysis, we concluded that a successful unilateral EC-IC bypass does not adversely affect postoperative cognitive function.

Extracranial to intracranial by-pass anastomosis: Review of our preliminary experience from a low volume center in Egypt

Background:

Cerebral revascularization is a useful microsurgical technique for the treatment of steno-occlusive intracranial ischemic disease, complex intracranial aneurysms that require deliberate occlusion of a parent artery and invasive skull base tumors. We describe our preliminary experience with extracranial-to-intracranial by-passes at a low volume center; and discuss clinical indications and microsurgical techniques, challenges in comparison to large advanced referral centers.

Materials and Methods:

Twenty-seven patients with hemodynamic ischemia or complex aneurysms or skull base tumors were operated at Cairo University Hospitals in the period between May 2009 and June 2014. All patients operated by a low flow by-pass were operated through a superficial temporal artery to middle cerebral artery (MCA) anastomosis. All patients chosen for a high flow by-pass were operated using a radial artery graft interposed between the MCAs distally and the common or the external carotid artery proximally. Patency was confirmed at the end of surgery using appearance on the table and confirmed after surgery by transcranial color-coded duplex or computed tomography angiography. All patient data were prospectively collected and retrospectively analyzed at the end of surgery.

Results:

Nineteen patients (70.4%) were operated upon for flow augmentation and eight patients (29.6%) were operated upon for flow replacement. A total of 30 anastomoses were performed. All except one were patent which gives a patency rate of 96.3%. There was one death in the present series resulting from a hyperperfusion syndrome. 89.5% of patients with hemodynamic ischemia stopped having symptoms after surgery. All but one patient operated for hemodynamic ischemia showed a considerable cognitive improvement after surgery. None of the patients operated upon for flow replacement showed improvement of oculomotor nerve function in spite of adequate intraoperative decompression. All patients treated for flow replacement showed the absence of recurrence on follow-up.

Conclusion:

Our initial results for both low and high flow by-pass procedures in our low volume center indicate that such complex surgical procedures are possible with results comparable to those obtained in other larger referral centers throughout the world. This procedure not only represents a more definitive treatment when compared to other endovascular or radiation treatments but is also much less costly when compared to other treatment modalities.

Collaterals: Implications in cerebral ischemic diseases and therapeutic interventions

Despite the tremendous progress made in the treatment of cerebrovascular occlusive diseases, many patients suffering from ischemic brain injury still experience dismal outcomes. Although rehabilitation contributes to post-stroke functional recovery, there is no doubt that interventions that promote the restoration of blood supply are proven to minimize ischemic injury and improve recovery. In response to the acutely decreased blood perfusion during arterial occlusion, arteriogenesis, the compensation of blood flow through the collateral circulation during arterial obstructive diseases can act not only in a timely fashion but also much more efficiently compared to angiogenesis, the sprouting of new capillaries, and a mechanism occurring in a delayed fashion while increases the total resistance of the vascular bed of the affected territory. Interestingly, despite the vast differences between the two vascular remodeling mechanisms, some crucial growth factors and cytokines involved in angiogenesis are also required for arteriogenesis. Understanding the mechanisms underlying vascular remodeling after ischemic brain injury is a critical step towards the development of effective therapies for ischemic stroke. The present article will discuss our current views in vascular remodeling acutely after brain ischemia, namely arteriogenesis, and some relevant clinical therapies available on the horizon in augmenting collateral flow that hold promise in treating ischemic brain injury. This article is part of a Special Issue entitled SI: Cell Interactions In Stroke.

Posterior auricular artery as an alternative donor vessel for extracranial-intracranial bypass surgery

BACKGROUND

Sometimes the superficial temporal artery (STA) is not available for an extracranial-intracranial (EC-IC) bypass procedure. An alternative vessel for an EC-IC bypass is the posterior auricular artery (PAA) if it extends to the temporoparietal area with a diameter large enough. We assessed the prevalence of an appropriate PAA as an alternative donor vessel and report three illustrative cases in which the PAA was used for EC-IC bypass surgery.

METHODS

A literature search was performed on the use of the PAA as a donor vessel for bypass surgery. Secondly, a prospective database of bypass surgeries was reviewed to calculate the prevalence of a PAA with a diameter of at least 1 mm in the parietotemporal area. Finally, three illustrative cases are reported that describe various indications for the revascularisation procedures with their clinical, surgical and imaging features.

RESULTS

Two articles have previously described the use of the PAA for bypass surgery and their results are summarised. The prevalence of a PAA that would be appropriate for an EC-IC bypass in patients with intracranial vascular pathology is 5.7%. The presented cases demonstrate that the PAA can be successfully used for EC-IC bypass surgery with good flow velocities and patency.

CONCLUSIONS

The PAA is a rarely described as an appropriate donor vessel for an EC-IC bypass. Its prevalence is 5.7% and it can successfully be used as an alternative donor vessel. The awareness among cerebrovascular surgeons about the presence of a PAA and knowledge about its anatomy may be valuable.

Stroke in patients with occlusion of the internal carotid artery: options for treatment

Ischemic stroke may occur in patients in whom vascular imaging shows the ipsilateral internal carotid artery (ICA) to be occluded. In younger patients this is often due to carotid artery dissection, while in older people this most likely results from cardiac embolism or thrombosis secondary to high-grade stenosis at the carotid bifurcation. Interventional techniques aim at recanalization of the carotid artery for early restoration of cerebral blood flow and secondary prevention of future strokes. In chronic ICA occlusion the ischemic infarct may be related to hemodynamic compromise. In this situation, extracranial-intracranial bypass surgery was introduced, but its role remains still unclear. Ischemic stroke may also occur in patients with a chronic occlusion of the contralateral ICA. This situation demands the usual stroke treatment, but surgical and neuroradiological interventions face a higher risk than unilateral vascular pathology. Medical treatment supports stroke prevention in carotid artery occlusion.

Endothelial progenitor cells augment collateralization and hemodynamic rescue in a model of chronic cerebral ischemia

Surgical flow augmentation for treatment of cerebral hemodynamic impairment remains controversial. Here, we investigated the benefit of endothelial progenitor cell (EPC) treatment in a rat model of chronic cerebral hypoperfusion. At repeated time points after 3-vessel occlusion (3-VO), animals were treated with 1 × 10(6) DiI-labeled (a) ex vivo-expanded embryonic-EPC (e-EPC), (b) cyclic AMP-differentiated embryonic-endothelial progenitor-derived cells (e-EPDC as biologic control) or, (c) saline. The cerebrovascular reserve capacity (CVRC) was assessed immediately before and on days 7 and 21 after 3-VO. Structural effects were assessed by latex perfusion, immunohistochemistry, and intravital fluorescence video microscopy on day 21. Three-vessel occlusion resulted in a significant impairment of the CVRC with better functional recovery after treatment with e-EPC (16.4±8%) compared with e-EPDC (3.7±8%) or saline (6.4±9%) by day 21 (P<0.05), which was paralleled by a significant increase in the vessel diameters of the anterior Circle of Willis, a significantly higher number of leptomeningeal anastomoses and higher parenchymal capillary density in e-EPC-treated animals. Interestingly, despite in vivo interaction of e-EPC with the cerebral endothelium, e-EPC incorporation into the cerebral vasculature was not observed. Our results suggest that EPC may serve as a novel therapeutic agent in clinical trials for nonsurgical treatment of chronic cerebral hemodynamic impairment.

Double-barrel bypass for cerebral ischemia: technique, rationale, and preliminary experience with 10 consecutive cases

BACKGROUND

In selected patients, extracranial-intracranial bypass remains an important treatment for the prevention of stroke. Traditionally, superficial temporal artery-middle cerebral artery (STA-MCA) bypass uses 1 STA branch. We have adopted a "double-barrel" technique in which both branches are joined with MCA recipients in distinct vascular territories.

OBJECTIVE

To assess the feasibility of routinely using both branches of the STA for cerebral revascularization.

METHODS

Ten consecutive patients underwent double-barrel bypass. Patients were selected if they demonstrated symptomatic MCA hypoperfusion resistant to medical therapy or had symptomatic moyamoya disease. Flow-directed bypass was performed to augment flow to the territories most at risk in each case, based on preoperative and intraoperative data. Computed tomography perfusion was routinely performed to evaluate baseline deficits and postoperative augmentation. Clinical data were analyzed to assess patient demographics and outcomes.

RESULTS

The double-barrel bypass was no more difficult technically than the traditional approach, with the second branch harvested through a small satellite incision. By isolating temporary occlusion to each territory, there was no additional ischemia to each brain region. No intraoperative complications or wound-healing issues occurred. Postoperative computed tomography perfusion studies all showed improvement, and delayed vascular imaging demonstrated universal graft patency. Nine of 10 patients have been asymptomatic since surgery, whereas 1 patient demonstrated symptoms in a separate vascular distribution.

CONCLUSION

Double-barrel STA-MCA bypass is both feasible and potentially advantageous. In our series, both bypass branches remained patent, augmenting flow to the territories most at need.

Chinese consensus statement on the evaluation and intervention of collateral circulation for ischemic stroke

Background

Collateral circulation is becoming more significant in the individual management strategy of ischemic stroke, there are more data updated recently.

Aim

To make the further acknowledgment of the evaluation and how to improving collateral flow, for better treatment selection.

Method

A panel of experts on stroke providing related statement based on review the results from most up‐to‐date clinical research.

Results

DSA is the gold standard in evaluating all levels of collaterals. CTA can be used for evaluating leptomeningeal collaterals, MRA for CoW, TCD or TCCS can be used as screening tool for primary evaluation. The treatment modalities include direct interventions, such as Extracranial–Intracranial bypass, and indirect interventions, as External counterpulsation and pressor therapy. The consideration of methodology to augment and improve can be considered on an individual basis.

Discussion

In this consensus, we interpret the definition, neuroimaging evaluation, intervention and potential strategy on collaterals in the future.

Conclusion

Assessment of collateral circulation is crucial for selecting therapeutic options, predicting infarction volume and making prognosis after ischemic stroke. Data is still needed to provide therapeutic evidence for many new developed technologies. Until more evidence is available, the clinical significance of applying the new technologies is unclear and perhaps limited.