Extracranial-intracranial arterial bypass for treatment of occlusion of the internal carotid artery

Extracranial-intracranial bypass surgery for occlusive atherosclerotic disease of the anterior cerebral circulation: protocol for a systematic review and meta-analysis

BACKGROUND

Occlusive atherosclerotic disease of the anterior cerebral circulation is one of the most common causes of anterior circulation ischemia and stroke. Treatment options include medical therapies (including antiplatelet use, blood pressure control, lipid reduction, and lifestyle modification) and extracranial-intracranial bypass surgery (such as superficial temporal artery-middle cerebral artery bypass). However, the optimal treatment remains unclear. The objective of this study will be to compare the efficacy of and extracranial-intracranial bypass surgery with that of other medical therapy in adult patients with occlusive atherosclerotic disease of the anterior cerebral circulation.

METHODS

This is the study protocol for a systematic review. We will search MEDLINE, EMBASE, Web of Science, and the Cochrane Library (from January 1980 onwards). We will include randomized controlled trials, quasi-experimental studies (non-randomized, interrupted time series), and observational studies (e.g., cohort studies and case-control studies), examining the efficacy of extracranial-intracranial bypass surgery compared to other treatments for adult patients with occlusive atherosclerotic disease of anterior cerebral circulation. Two team members will independently screen all citations, full-text articles, and abstract data. Potential conflicts will be resolved through discussion. The primary outcome will include stroke or death. The secondary outcomes will include intracranial hemorrhage, transient ischemic attack, and myocardial infarction. The study methodological quality (or bias) will be appraised using appropriate tools. If feasible, we will conduct random effects meta-analysis. Additional analyses will be conducted to explore the potential sources of heterogeneity (e.g., study design, geographical location, or risk of bias).

DISCUSSION

This review will evaluate the evidence on the efficacy of extracranial-intracranial bypass surgery for adult patients with occlusive atherosclerotic disease of the anterior cerebral circulation. We anticipate that our findings will be of interest to patients, their families, caregivers, healthcare professionals, and in making optimal treatment selection. Implications for future clinical and epidemiological research will be discussed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018105513.

Current Open Surgical Indications for Revascularization in Cerebral Ischemia

Cerebral revascularization was pioneered half a century ago. Gradual improvements in microsurgical instrumentation and training in microsurgical techniques have allowed significant changes that improved outcomes in neurosurgery, extrapolating this knowledge to other neurosurgical diseases (brain tumor, aneurysms, and skull base tumor surgery). But the popularity of cerebral bypass procedures was followed by their decline, given the lack of clear benefit of bypass surgery in chronic cerebrovascular ischemia after the EC-IC bypass studies. Over the last couple of decades, the formidable advance of neuro-endovascular techniques for revascularization has lessened the need for application of open cerebral revascularization procedures, either for flow augmentation or flow replacement. However, there is still a select group of patients with chronic cerebral ischemia, for whom open cerebral revascularization with flow augmentation is the only treatment option available, and this will be the objective of our current review.

Superficial Temporal Artery Trunk-to-Middle Cerebral Artery Bypass with Short Radial Artery Interposition Graft for Symptomatic Internal Carotid Artery Occlusion

OBJECTIVE

We investigated the use of high-flow superficial temporal artery trunk-to-radial artery-to-middle cerebral artery (STAt-RA-MCA) bypass to prevent ischemic stroke in patients with symptomatic internal carotid artery occlusion (SICAO).

METHODS

We retrospectively analyzed the data from patients with SICAO who had undergone high-flow STAt-RA-MCA bypass in our center from October 2014 to November 2017. The incidence of ischemic stroke, changes in cerebral blood flow, characteristics of perioperative complications, and related factors determining the blood flow rate in the graft were analyzed.

RESULTS

From October 2014 to November 2017, we treated 21 patients with SICAO using high-flow STAt-RA-MCA bypass. A total of 42 ischemic stroke events had been reported within 6 months before surgery. The ipsilateral/contralateral mean transit time (I/C MTT) ratio before surgery was 1.24 ± 0.10 (range, 1.14-1.51). During a median follow-up period of 692 days (range, 212-1114), 3 transient ischemic attacks occurred in 3 patients; 18 patients (85.7%) did not experience recurrent stroke. The patency rate of the bypass graft was 95.2% (20 of 21). The I/C MTT ratio was 1.06 ± 0.11 on postoperative day 1 in all patients and was significantly different from the preoperative I/C MTT ratio (P < 0.001). The surgical complication rate was 9.5% (2 of 21), and no reoperation was required.

CONCLUSION

Our results suggest that high-flow STAt-RA-MCA bypass can effectively reduce the risk of stroke in patients with SICAO. Moreover, the surgical procedure is a highly safe procedure. Further randomized controlled studies are required to draw more precise conclusions.

Mattress anastomosis in micro vascular reconstruction: technical note

BACKGROUND

Superficial temporal artery-to-middle cerebral artery (STA-MCA) anastomosis is a common procedure for neurosurgeons. The surgery necessarily requires accurate and speedy manipulation of microscope, for which a specific training is needed. Unexpected bypass occlusion sometimes happen during surgery.

OBJECTIVE

Generally, conventional interrupted or continuous suture has been used for vascular anastomosis, despite various ideas have been attempted in the other surgery fields. We propose a horizontal mattress suture technique for intracranial microvascular bypass surgery. This is the first report ever published on intracranial vascular anastomosis.

METHODS

We had four patients of STA-MCA bypass surgery with "mattress anastomosis" from March to May of 2012.

RESULTS

During the procedure, there was no bypass occlusion and good patency was confirmed in all cases.

CONCLUSION

Intimae of the recipient and the donor blood vessel contact each other precisely with this technique. Although a long-term assessment of patency is needed, it is useful for the intracranial bypass surgery.

Neurological complications of acute ischaemic stroke

Complications after ischaemic stroke, including both neurological and medical complications, are a major cause of morbidity and mortality. Neurological complications, such as brain oedema or haemorrhagic transformation, occur earlier than do medical complications and can affect outcomes with potential serious short-term and long-term consequences. Some of these complications could be prevented or, when this is not possible, early detection and proper management could be effective in reducing the adverse effects. However, there is little evidence-based data to guide the management of these neurological complications. There is a clear need for improved surveillance and specific interventions for the prevention, early diagnosis, and proper management of neurological complications during the acute phase of stroke to reduce stroke morbidity and mortality.

Perfusion CT scanning and CT angiography in the evaluation of extracranial-intracranial bypass grafts

OBJECT

Extracranial-intracranial (EC-IC) bypass surgery remains an important treatment alternative for patients with occlusive cerebrovascular disease. The aim of the present study was to use perfusion CT and CT angiography (CTA) to evaluate cerebral hemodynamics and bypass patency in patients with occlusive cerebrovascular disease before and after EC-IC bypass surgery.

METHODS

Ten patients underwent perfusion CT and CTA before and after bypass surgery. Preoperative and postoperative digital subtraction angiography served as the diagnostic gold standard. An artery bypass was established from the superficial temporal artery to a cortical branch of the middle cerebral artery. Perfusion CT scanning was performed at the level of the basal ganglia. Color-coded perfusion maps of cerebral blood volume, cerebral blood flow, and time to peak were calculated.

RESULTS

Preoperative perfusion CT showed significant prolonged time to peak and reduced cerebral blood flow of the affected hemisphere. Postoperative neurological deterioration did not develop in any patient. Computed tomography angiography provided adequate evaluation of the anastomoses as well as the course and caliber of the bypass and confirmed bypass patency in all patients. Postoperative perfusion CT showed improved cerebral hemodynamics with a return to nearly normal perfusion parameters.

CONCLUSIONS

Computed tomography angiography is a noninvasive and reliable tool for evaluating patients with EC-IC bypass. Perfusion CT allows monitoring of hemodynamic changes after bypass surgery. The combination of both modalities enables noninvasive anatomical and functional analysis of superficial temporal artery-middle cerebral artery anastomoses using a single CT protocol. Hemodynamic evaluation of patients with occlusive cerebrovascular disease before and after surgery may improve the prediction of outcome and may help identify patients in whom a bypass procedure can be performed.

Secondary prevention of atherothrombotic events after ischemic stroke

Atherosclerotic vascular disease is the leading cause of ischemic stroke, resulting in occlusive or severely stenotic lesions of major intracranial or extracranial arteries and narrowing of small penetrating arteries of the brain. Atherosclerosis of the coronary arteries (ie, coronary artery disease) is an indirect cause of cardioembolic stroke secondary to myocardial infarction. Ischemic heart disease may also be complicated by atrial fibrillation and cardioembolic stroke. Prevention of recurrent stroke and other ischemic events, including myocardial infarction, is a key component of treatment for patients with symptomatic ischemic cerebrovascular disease. Prevention of recurrent stroke involves controlling those factors that promote the course of atherosclerosis, including hypertension, hyperlipidemia, diabetes mellitus, and smoking, as well as such local interventions as carotid endarterectomy and endovascular treatment. Nevertheless, administration of antiplatelet agents remains the core of management for preventing recurrent stroke and other cardiovascular events in at-risk patients.

Secondary prevention of atherothrombotic events after ischemic stroke

Atherosclerotic vascular disease is the leading cause of ischemic stroke, resulting in occlusive or severely stenotic lesions of major intracranial or extracranial arteries and narrowing of small penetrating arteries of the brain. Atherosclerosis of the coronary arteries (ie, coronary artery disease) is an indirect cause of cardioembolic stroke secondary to myocardial infarction. Ischemic heart disease may also be complicated by atrial fibrillation and cardioembolic stroke. Prevention of recurrent stroke and other ischemic events, including myocardial infarction, is a key component of treatment for patients with symptomatic ischemic cerebrovascular disease. Prevention of recurrent stroke involves controlling those factors that promote the course of atherosclerosis, including hypertension, hyperlipidemia, diabetes mellitus, and smoking, as well as such local interventions as carotid endarterectomy and endovascular treatment. Nevertheless, administration of antiplatelet agents remains the core of management for preventing recurrent stroke and other cardiovascular events in at-risk patients.

External carotid artery angioplasty and stenting to augment cerebral perfusion in the setting of subacute symptomatic ipsilateral internal carotid artery occlusion

✓The authors performed external carotid artery (ECA) angioplasty and stenting in a 45-year-old man who had presented with right hemispheric crescendo ischemic symptoms stemming from acute right internal carotid artery occlusion (ICAO). This unique application of ECA angioplasty and stenting augmented cerebral perfusion and improved clinical symptoms. In certain situations, ECA stenting can increase cerebral perfusion in the setting of ICAO and ECA stenosis. The authors are the first to describe this approach in this context.

Anesthetic considerations for intraoperative management of cerebrovascular disease in neurovascular surgical procedures

Despite new surgical methods and interventions a considerable number of patients who undergo neurovascular procedures emergently or electively have substantial mortality, morbidity, and disability. Sound knowledge of pathophysiology of cerebral hypoperfusion, reliable and timely information from monitoring devices, and appropriate choice of therapeutic intervention is essential for successful anesthetic management of these patients. The management of perioperative vasospasm and temporary ischemia during aneurysm clipping require an understanding of cerebral vascular pathophysiology and neuroprotective measures.

Superficial temporal artery to middle cerebral artery bypass

The superficial temporal artery to middle artery bypass is a technique that allows the blood supply from the extracranial carotid circulation to be routed to the distal middle cerebral artery branches. The procedure allows blood flow to bypass proximal lesions of the intracranial vasculature. The performance of this bypass requires specialized microvascular training and the use of microvascular techniques. The techniques involved in performing these procedures include microdissection of the superficial temporal artery in the scalp, microdissection of the recipient middle cerebral artery branches near the sylvian fissure, and anastomosis techniques using either microvascular sutures or a microanastomotic device. The successful completion of the bypass and subsequent patency requires meticulous attention to technical details.