Endovascular Intervention

1-    Practicing physician must have a valid license to practice medicine within their respective countries.

2-    Practicing physician specialization criteria should be defined at a national level according to national medical regulations. They must have accomplished training in one of the following medical specialties: Neurology, Neurosurgery, Intervention radiology.

3-    Practicing physician must have completed an accredited post graduate dedicated training in intervention neurology subspecialty. This program should have not less than 24 months mandatory dedicated training in intervention neurology.

Good practice statement

II)  REQUIREMENTS FOR PRACTICING INSTITUTIONS/DEPARTMENTS

1- Intervention neurology practicing must take place in institutions/departments operating in accordance with the national standards of medical service providence.

2- All patients would be treated at a center offering a full spectrum of neuroendovascular care.

3- Ideally, treating centers should have the following requirements at least to provide safe and efficient intervention neurology services:

a. Offers full spectrum of neuroendovascular therapy (including aneurysm treatment, surgical and endovascular, arteriovenous malformations, arteriovenous fistulas, etc.)

b. At least 250 case per year of stroke patients’ management in a dedicated neuroscience department.

c. Dedicated intensive care unit/stroke unit to manage pre- and post-operative patients.

d. Standardized care pathways should be implemented with clinical practice guidelines, order sets, and other tools to ensure consistent care delivery and minimize practice variability. This should apply to providers, and nursing and ancillary staff.

Strong recommendation & High level of evidence (Pierot et al., 2018)

1- Preprocedural documentation for elective diagnostic cervicocerebral/spinal catheter angiography, must contain the following:

a. Clinically significant history, including indications for the procedure.

b. Clinically significant physical examination and diagnostic imaging findings, including neurological and vascular examinations appropriate to the procedure performed, and a general examination of relevant organ systems.

c. Laboratory evaluation as appropriate, including but not limited to measurement of hemoglobin, hematocrit, creatinine, electrolytes, and coagulation parameters.

d. Informed consent must be in compliance with all local laws and policies.

Strong recommendation & High level of evidence (ACR-ASNR-SIR-SNIS Practice Parameter, 2021)

1- Diagnostic cervicocerebral/spinal catheter angiography is a proven, safe, and effective procedure for evaluating many intracranial and extracranial disorders, especially vascular abnormalities of the head, neck, and brain. Strong recommendation & Moderate level of evidence (Wojak, J.C. et al., 2015)

2- Diagnostic cervicocerebral/spinal catheter angiography has been considered the gold standard for judging the accuracy of other intracranial or extracranial vascular imaging modalities. Strong recommendation & High level of evidence (Wojak, J.C. et al., 2015)

3- The following list of indications helps to focus on the primary indications for diagnostic cervicocerebral/spinal catheter angiography and therefore helps to avoid unnecessary testing:

a. Definition of the presence and extent of atherosclerotic occlusive disease and thromboembolic phenomena and as an aid in planning intervention.

b. Definition of the etiology of cervicocerebral/spinal hemorrhage.

c.  Definition of the presence, location, and anatomy of extra- or intracranial and spinal aneurysms and vascular malformations.

d. Evaluation of vasospasm related to subarachnoid hemorrhage or drug-induced vasculopathy.

e. Definition of the vascular supply to cervicocerebral/spinal tumors.

f. Diagnosis and definition of the nature and extent of cervicocerebral/spinal congenital or acquired vascular abnormalities.

g. Definition of the presence of venous occlusive disease.

h. Definition of the relevant vascular anatomy for planning or evaluating a therapeutic intervention.

Strong recommendation & High level of evidence (ACR-ASNR-SIR-SNIS Practice Parameter, 2021)

4-  The threshold for these indications is 99%. When fewer than 99% of the procedures are for these indications, the institution should review the process of patient selection. Strong recommendation & High level of evidence (ACR-ASNR-SIR-SNIS Practice Parameter, 2021)

5- There are no absolute contraindications to diagnostic cervicocerebral catheter angiography. Relative contraindications include hypotension, severe hypertension, and coagulopathy, clinically significant sensitivity to iodinated contrast material, renal insufficiency, and congestive heart failure. Strong recommendation & Moderate level of evidence (ACR-ASNR-SIR-SNIS Practice Parameter, 2021)

6- Patient management should address these relative contraindications prior to the procedure. When possible, every effort should be made to correct or control these clinical situations before the procedure. Strong recommendation & Moderate level of evidence (ACR-ASNR-SIR-SNIS Practice Parameter, 2021)

7-  Diagnostic cervicocerebral/spinal catheter angiographic examinations must be performed by or under the supervision of and interpreted by a physician who has the appropriate qualification and training in the field of cervicocerebral/spinal catheter angiography. Strong recommendation & High level of evidence (ACR-ASNR-SIR-SNIS Practice Parameter, 2021)

B. Acute Ischemic Stroke (Mechanical Thrombectomy)
From 0 to 6 hours From Onset:

1-    Patients should receive mechanical thrombectomy with a stent retriever if they meet all the following criteria: (1) pre stroke mRS score of 0 to 1; (2) causative occlusion of the internal carotid artery or MCA segment 1 (M1); (3) age ≥18 years; (4) NIHSS score of ≥6; (5) ASPECTS of ≥6; and (6), treatment can be initiated (groin puncture) within 6 hours of symptom onset. Strong recommendation & high level of evidence (Bush CK et al., 2016)

2-    Although the benefits are uncertain, the use of mechanical thrombectomy with stent retrievers may be reasonable for carefully selected patients with AIS in whom treatment can be initiated (groin puncture) within 6 hours of symptom onset and who have causative occlusion of the MCA segment 2 (M2) or MCA segment 3 (M3) portion of the MCAs. Conditional recommendation & moderate level of evidence (Lemmens R et al., 2016)

3-    Although its benefits are uncertain, the use of mechanical thrombectomy with stent retrievers may be reasonable for patients with AIS in whom treatment can be initiated (groin puncture) within 6 hours of symptom onset and who have pre stroke mRS score >1, ASPECTS <6, or NIHSS score<6, and causative occlusion of the internal carotid artery (ICA) or proximal MCA (M1). Conditional recommendation & moderate level of evidence (Lemmens R et al., 2016)

4-    Although the benefits are uncertain, the use of mechanical thrombectomy with stent retrievers may be reasonable for carefully selected patients with AIS in whom treatment can be initiated (groin puncture) within 6 hours of symptom onset and who have causative occlusion of the anterior cerebral arteries, vertebral arteries, basilar artery, or posterior cerebral arteries. Conditional recommendation & moderate level of evidence (Lemmens R et al., 2016)

From 6 to 24 hours From Onset:

1- In selected patients with AIS within 6 to 16 hours of last known normal who have LVO in the anterior circulation and meet other DAWN or DEFUSE 3 eligibility criteria, mechanical thrombectomy is recommended. Strong recommendation & high level of evidence (Nogueira RG, et al., 2017 and Albers GW et al., 2017)

2- In selected patients with AIS within 16 to 24 hours of last known normal who have LVO in the anterior circulation and meet other DAWN eligibility criteria, mechanical thrombectomy is reasonable. Conditional recommendation & moderate level of evidence (Nogueira RG, et al., 2017 and Albers GW et al., 2017)

Thrombectomy Technique:

1-     The use of stent retrievers is indicated in preference to the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) device. Strong recommendation & high level of evidence (Lapergue B, et al., 2017)

2-     The use of mechanical thrombectomy devices other than stent retrievers as first-line devices for mechanical thrombectomy may be reasonable in some circumstances, but stent retrievers remain the first choice. Conditional recommendation & moderate level of evidence (Lapergue B, et al., 2017)

3-  The use of a proximal balloon guide catheter or a large-bore distal-access catheter, rather than a cervical guide catheter alone, in conjunction with stent retrievers may be beneficial. Conditional recommendation & high level of evidence (Dippel DW et al., 2016)

4- The technical goal of the thrombectomy procedure should be reperfusion to a modified Thrombolysis in Cerebral Infarction (mTICI) grade 2b/3 angiographic result to maximize the probability of a good functional clinical outcome. Strong recommendation & high level of evidence (Marks MP et al., 2013)

5- To ensure benefit, reperfusion to mTICI grade 2b/3 should be achieved as early as possible within the therapeutic window. Strong recommendation & high level of evidence (Marks MP et al., 2013)

6-  Use of salvage technical adjuncts including intra-arterial thrombolysis may be reasonable to achieve mTICI 2b/3 angiographic results. Conditional recommendation & low level of evidence (Dippel DW et al., 2016)

7- In the 6- to 24-hour thrombectomy window evaluation and treatment should proceed as rapidly as possible to ensure access to treatment for the greatest proportion of patients. Strong recommendation & moderate level of evidence (Dippel DW et al., 2016)

8-  Direct aspiration thrombectomy as first-pass mechanical thrombectomy is recommended as noninferior to stent retriever for patients who meet all the following criteria: (1) pre stroke mRS score of 0 to 1; (2) causative occlusion of the internal carotid artery or M1; (3) age ≥18 years; (4) NIHSS score of ≥6; (5) ASPECTS ≥6; and (6) treatment initiation (groin puncture) within 6 hours of symptom onset. Strong recommendation & moderate level of evidence (Dippel DW et al., 2016)

9-     It is reasonable to select an anesthetic technique during EVT for AIS on the basis of individualized assessment of patient risk factors, technical performance of the procedure, and other clinical characteristics. Conditional recommendation & moderate level of evidence (Lowhagen P et al., 2017)

10-  Treatment of tandem occlusions (both extracranial and intracranial occlusions) when performing mechanical thrombectomy may be reasonable. Conditional recommendation & moderate level of evidence (Lowhagen P et al., 2017)

11-  The safety and efficacy of IV glycoprotein IIb/IIIa inhibitors administered during endovascular stroke treatment are uncertain. Conditional recommendation & low level of evidence (Lowhagen P et al., 2017)

Other Endovascular Therapies:

1-    Mechanical thrombectomy with stent retrievers is recommended over intra-arterial fibrinolysis as first-line therapy. Strong recommendation & high level of evidence (Lapergue B, et al., 2017)

2-    Intra-arterial fibrinolysis initiated within 6 hours of stroke onset in carefully selected patients who have contraindications to the use of IV alteplase might be considered, but the consequences are unknown. Conditional recommendation & low level of evidence (Lapergue B, et al., 2017)

C. Endovascular Management For Secondary Prevention Of Ischemic Stroke

Intracranial Large Artery Atherosclerosis

1-    In patients with severe stenosis (70%-99%) of a major intracranial artery and actively progressing symptoms or recurrent TIA or stroke after institution of aspirin and clopidogrel therapy, achievement of SBP< 140 mmHg, and high-intensity statin therapy (so-called medical failures), the usefulness of angioplasty alone or stent placement to prevent ischemic stroke in the territory of the stenotic artery is unknown. Strong recommendation, high [AA1] level of evidence (Chimowitz MI et al., 2005)

2-    In patients with stroke or TIA attributable to severe stenosis (70%–99%) of a major intracranial artery, angioplasty, and stenting should not be performed as an initial treatment, even for patients who were taking an antithrombotic agent at the time of the stroke or TIA. Conditional recommendation & high level of evidence (Chimowitz MI et al., 2011)

3-    In patients with a stroke or TIA attributable to moderate stenosis (50%–69%) of a major intracranial artery, angioplasty or stenting is associated with excess morbidity and mortality compared with medical management alone. Conditional recommendation & moderate level of evidence (Chimowitz MI et al., 2005 and Amarenco P et al., 2020)[AA2] 

4-    In patients with stroke or TIA attributable to 50% to 99% stenosis or occlusion of a major intracranial artery, extracranial-intracranial bypass surgery is not recommended. Conditional recommendation & moderate level of evidence (kwon SU et al., 2005)

Extracranial Carotid stenosis

1-    In patients with a TIA or non-disabling ischemic stroke within the past 6 months and ipsilateral severe (70%–99%) carotid artery stenosis, carotid endarterectomy (CEA) is recommended to reduce the risk of future stroke, provided that perioperative morbidity and mortality risk is estimated to be<6%. Strong recommendation & high level of evidence (Rothwell PM et al., 2003)

2- In patients with ischemic stroke or TIA and symptomatic extracranial carotid stenosis who are scheduled for carotid artery stenting (CAS) or CEA, procedures should be performed by operators with established periprocedural stroke and mortality rates of<6%. Strong recommendation & high level of evidence ( Barnett HJM et al., 1991)

3- In patients with carotid artery stenosis and a TIA or stroke, intensive medical therapy, with antiplatelet therapy, lipid lowering therapy, and treatment of hypertension, is recommended to reduce stroke risk. Strong recommendation & high level of evidence (Barnett HJM et al., 1991)

4- In patients with recent TIA or ischemic stroke and ipsilateral moderate (50%–69%) carotid stenosis as documented by catheter-based imaging or noninvasive imaging, CEA is recommended to reduce the risk of future stroke, depending on patient-specific factors such as age, sex, and comorbidities, if the perioperative morbidity and mortality risk is estimated to be<6%. Strong recommendation & moderate level of evidence( Barnett HJM et al., 1991)

5- In patients ≥70 years of age with stroke or TIA in whom carotid revascularization is being considered, it is reasonable to select CEA over CAS to reduce the periprocedural stroke rate. Conditional recommendation & high level of evidence (Howard G, et al., 2016)

6-    In patients in whom revascularization is planned within 1 week of the index stroke, it is reasonable to choose CEA over CAS to reduce the periprocedural stroke rate. Conditional recommendation & high level of evidence (Rantner B, et al., 2017)

7- In patients with TIA or nondisabling stroke, when revascularization is indicated, it is reasonable to perform the procedure within 2 weeks of the index event rather than delay surgery to increase the likelihood of stroke-free outcome. Conditional recommendation & high level of evidence ( Rothwell PM, et al., 2004)

8-    In patients with symptomatic severe stenosis (≥70%) in whom anatomic or medical conditions are present that increase the risk for surgery (such as radiation-induced stenosis or restenosis after CEA) it is reasonable to choose CAS to reduce the periprocedural complication rate. Conditional recommendation & high level of evidence (Yadav JS, et al., 2004)

9- In symptomatic patients at average or low risk of complications associated with endovascular intervention, when the ICA stenosis is ≥70% by noninvasive imaging or >50% by catheter-based imaging and the anticipated rate of periprocedural stroke or death is<6%. CAS may be considered as an alternative to CEA for stroke prevention, particularly in patients with significant cardiovascular comorbidities predisposing to cardiovascular complications with endarterectomy. Conditional recommendation & moderate level of evidence (Bratt TG, et al., 2010)

10- In patients with a recent stroke or TIA (past 6 months), the usefulness of trans carotid artery revascularization (TCAR) for the prevention of recurrent stroke and TIA is uncertain. Conditional recommendation & moderate level of evidence (Schermerhon ML et al., 2019)

11- In patients with recent TIA or ischemic stroke and when the degree of stenosis is< 50%, revascularization with CEA or CAS to reduce the risk of future stroke is not recommended. Conditional recommendation & high level of evidence (Rothwell PM et al., 2003)

12- In patients with a recent (within 120 days) TIA or ischemic stroke ipsilateral to atherosclerotic stenosis or occlusion of the middle cerebral or carotid artery, extracranial intracranial bypass surgery is not recommended Conditional recommendation & high level of evidence (Powers WJ et al., 2011)

Extracranial Vertebral artery stenosis

1- In patients with recently symptomatic extracranial vertebral artery stenosis, intensive medical therapy (antiplatelet therapy, lipid-lowering, BP control) is recommended to reduce stroke risk. Strong recommendation & high level of evidence ( Markus HS et al., 2019)

2- In patients with ischemic stroke or TIA and extracranial vertebral artery stenosis who are having symptoms despite optimal medical treatment, the usefulness of stenting is not well established. Conditional recommendation & weak level of evidence( Markus HS et al., 2019)

3- In patients with ischemic stroke or TIA and extracranial vertebral artery stenosis who are having symptoms despite optimal medical treatment, the usefulness of open surgical procedures, including vertebral endarterectomy and vertebral artery transposition, is not well-established. Conditional recommendation & weak level of evidence( Markus HS et al., 2019)

Moyamoya Disease

1-  In patients with Moyamoya disease and a history of ischemic stroke or TIA, surgical revascularization with direct or indirect extracranial-intracranial bypass can be beneficial for the prevention of ischemic stroke or TIA. Conditional recommendation & moderate level of evidence (Deng X et al., 2018)

2-  Inpatients with moyamoya disease and a history of ischemic stroke or TIA, the use of antiplatelet therapy, typically aspirin monotherapy, for the prevention of ischemic stroke or TIA may be reasonable. Conditional recommendation & moderate level of evidence ( Jeon JP et al., 2018)

Carotid Web

1- In patients with carotid web in the distribution of ischemic stroke and TIA, without other attributable causes of stroke, antiplatelet therapy is recommended to prevent recurrent ischemic stroke or TIA. Strong recommendation & high level of evidence (Haussen DC et al., 2017)

2- In patients with carotid web in the distribution of ischemic stroke refractory to medical management, with no other attributable cause of stroke despite comprehensive workup, carotid stenting or CEA may be considered to prevent recurrent ischemic stroke. Conditional recommendation & weak level of evidence (Haussen DC et al., 2017)

Fibromuscular Dysplasia

1- In patients with fibromuscular dysplasia (FMD) and a history of ischemic stroke or TIA without other attributable causes, antiplatelet therapy, BP control, and lifestyle modification are recommended for the prevention of future ischemic events. Strong recommendation & high level of evidence( Gornik HL et al., 2019)

2- In patients with a history of ischemic stroke or TIA attributable to dissection, with FMD, and no evidence of intraluminal thrombus, it is reasonable to administer antiplatelet therapy for the prevention of future ischemic events. Conditional recommendation & moderate level of evidence( Gornik HL et al., 2019)

3- In patients with cervical carotid artery FMD and recurrent ischemic stroke without other attributable causes despite optimal medical management, carotid angioplasty with or without stenting may be reasonable to prevent ischemic stroke. Conditional recommendation & moderate level of evidence( Smith LL et al., 1987)

Dolichoectasia

1- In patients with vertebrobasilar dolichoectasia and a history of ischemic stroke or TIA without other attributable causes, the use of antiplatelet or anticoagulant therapy is reasonable for the prevention of recurrent ischemic events. Conditional recommendation & moderate level of evidence (Passero SG et al., 2008)

D. Endovascular Management Of Aneurysmal Subarachnoid Hemorrhage

1-  In patients with spontaneous SAH with high level of concern for aneurysmal source and a negative or CT angiography ,digital subtraction angiography is indicated to diagnose/ exclude cerebral aneurysm(s). Strong recommendation & low level of evidence (Catapano JS et al., 2019 & Howard BM et al., 2019)

2- In patients with SAH from confirmed cerebral aneurysm(s), DSA can be useful to determine optimal strategy for aneurysm intervention. Conditioned recommendation & low level of evidence (Nagai M & Watanabe E, 2010)

3-  For patients with aSAH, timely transfer from hospitals with low case volume to higher-volume centers with multidisciplinary neurointensive care services, comprehensive stroke center capabilities, and experienced cerebrovascular surgeons/ neuroendovascular interventionalists is recommended to improve outcomes. Strong recommendation & moderate level of evidence (Buscot MJ et al., 2022 & Phuong NT et al., 2021)

4- For patients with aSAH, surgical or endovascular treatment of the ruptured aneurysm should be performed as early as feasible after presentation, preferably within 24 hours of onset, to improve outcome. Strong recommendation & low level of evidence  (Oudshoorn SC, et al., 2014)

5- For patients with aSAH, the ruptured aneurysm should be evaluated by specialist(s) with endovascular and surgical expertise to determine the relative risks and benefits of surgical or endovascular treatment according to patient and aneurysm characteristics. Strong recommendation & low level of evidence (Hoh, BL et al., 2023)

6- For patients with aSAH, complete obliteration of the ruptured aneurysm is indicated whenever to reduce the risk of rebleeding and retreatment. Strong recommendation & low level of evidence (Pierot L et al., 2020)

7- For patients with aSAH in whom complete obliteration of the ruptured aneurysm by either clipping or primary coiling treatment is not feasible in the acute phase, partial obliteration to secure the rupture site and retreatment in a delayed fashion in those with functional recovery are reasonable to prevent rebleeding. Conditioned recommendation & low level of evidence (Hoh, BL et al., 2023)

8- For patients with aSAH from ruptured aneurysms of the posterior circulation that are amenable to coiling, coiling is indicated in preference to clipping to improve outcome. Strong recommendation & high level of evidence (Lindgren A et al., 2018)

9- For patients >70 years of age with aSAH, the superiority of coiling or clipping to improve outcome is not well established. Conditioned recommendation & high level of evidence (Ryttlefors M et al., 2008)

10- For patients <40 years of age with aSAH, clipping of the ruptured aneurysm might be considered the preferred mode of treatment to improve durability of the treatment and outcome. Conditioned recommendation  with very low level of evidence (Ryttlefors M et al., 2008)

11- For patients with aSAH from ruptured wide-neck aneurysms not amenable to surgical clipping or primary coiling, endovascular treatment with stent-assisted coiling or flow diverters is reasonable to reduce the risk of rebleed. Conditioned recommendation & very low level of evidence (Ten Brinck MFM et al., 2022)

12- For patients with aSAH from ruptured fusiform/blister aneurysms, the use of flow diverters is reasonable to reduce mortality. Conditioned recommendation & very low level of evidence (Zhu D et al., 2018)

13- In patients with aSAH and severe vasospasm, use of intra-arterial vasodilator therapy may be reasonable to reverse cerebral vasospasm and reduce the progression and severity of DCI. Conditioned recommendation, low level of evidence (Ido K et al., 2020 & Giorgianni A et al., 2022)

14- In patients with aSAH and severe vasospasm, cerebral angioplasty may be reasonable to reverse cerebral vasospasm and reduce the progression and severity of DCI. Conditioned recommendation low level of evidence (Schacht H et al., 2020)

E. Brain Arteriovenous Fistula And Malformation Embolization

1-    Digital subtraction catheter cerebral angiography (DSA)—including 2D, 3D, and reformatted cross-sectional views when appropriate—is recommended in the pre-treatment assessment of cerebral AVMs. Strong recommendation & low level of evidence (De Leacy, R. et al., 2022)

2-    It is recommended that endovascular embolization of cerebral AVMs be performed in the context of a complete multidisciplinary treatment plan aiming for obliteration of the AVM and cure. Strong recommendation & low level of evidence (De Leacy, R. et al., 2022)

3-    Embolization of brain AVMs before surgical resection can be useful to reduce intraoperative blood loss, morbidity, and surgical complexity. Conditioned recommendation & low level of evidence (De Leacy, R. et al., 2022)The role of primary curative embolization of cerebral AVMs is uncertain, particularly as compared to microsurgery and radiosurgery with or without adjunctive embolization. Further research is needed, particularly with regard to risk for AVM recurrence. Conditioned recommendation & very low level of evidence (De Leacy, R. et al., 2022)

4-    Targeted embolization of high-risk features of ruptured brain AVMs may be considered to reduce the risk for recurrent hemorrhage. Conditioned recommendation & very low level of evidence (De Leacy, R. et al., 2022)

5-    Palliative embolization may be useful to treat symptomatic AVMs in which curative therapy is otherwise not possible. Conditioned recommendation & low level of evidence (De Leacy, R. et al., 2022)

6-    Imaging follow-up after apparent cure of brain AVMs is recommended to assess for recurrence. Although non-invasive imaging may be used for longitudinal follow-up, DSA remains the gold standard for residual or recurrent AVM detection in patients with concerning imaging and/or clinical findings. Strong recommendation & very low level of evidence (De Leacy, R. et al., 2022)

7-    Improved national and international reporting of patients of all ages with brain AVMs, their treatments, side effects from treatment, and their long-term outcomes would enhance the ability to perform clinical trials and improve the rigor of research into this rare condition. Strong recommendation & very low level of evidence (De Leacy, R. et al., 2022)

F. Spinal Arteriovenous Fistula And Malformation Embolization

1- Digital subtraction angiography (DSA), given its higher spatial and temporal resolution, remains superior to non-invasive modalities in identifying relevant dural AVF or AVM angioarchitecture features as compared with non-invasive modalities. Strong recommendation & High level of evidence (De Leacy, R. et al., 2022)

2- Angioarchitecture features, including feeding artery aneurysms, nidus aneurysms, large-caliber arteriovenous fistulous connections, and venous outflow stenoses, can be visualized to lesser or greater degrees by non-invasive imaging such as MR angiography (MRA) and CT angiography (CTA). Conditioned recommendation & Moderate level of evidence (Settecase F and Rayz VL, 2021)

3- The presence of spinal dural AVF is an indication for treatment in all patients; embolization maybe contraindicated in those patients in whom the anterior spinal artery originates from the same pedicle as the spinal dural AVF. Conditioned recommendation & moderate level of evidence (Narayanan, S. et al., 2012)

4- The indications for embolization of spinal cord AVMs include all symptomatic patients with lesions that can be cured; adjuvant therapy before surgery/radiosurgery; and palliative therapy when total obliteration is not practical and the patient suffers from progressive neurologic deficit or high risk of hemorrhage (associated aneurysm or pseudoaneurysm, previous hemorrhage) or when partial embolization is thought to be of benefit (presence of AVF, outflow restriction with venous ectasia). Strong recommendation & Moderate level of evidence (Narayanan, S. et al., 2012)

G. Head, Neck And Brain Tumor Embolization

1-  Endovascular embolization of highly vascular head, neck and brain tumors is undertaken to devascularise the lesion with the goal of minimizing blood loss and decreasing operating time. Conditioned recommendation & Moderate level of evidence (Duffis, E.J. et al., 2012)

2- In certain instances, embolization may be used as the sole treatment for palliation by decreasing the size of the tumor and reducing pain in patients who are deemed non-operable candidates. Conditioned recommendation & Moderate level of evidence (Tasar M & Yetiser S, 2004)

3- The following list summarizes vascular tumors that are commonly treated with adjunct embolization prior to operative resection:

a. Juvenile nasopharyngeal angiofibroma (JNA)

b. Hemangiopericytoma

c. Glomus jugulare and other paragangliomas

d. Meningiomas

e. Hemangioblastoma

Conditioned recommendation & Moderate level of evidence (Duffis, E.J. et al., 2012)

4- Digital subtraction angiography may provide additional information to supplement the clinical examination and findings on CT or MRI imaging. Angiography allows identification of displaced feeders to the tumor, facilitating their localization and ligation during surgery. In addition, the extent of tumor growth around the internal carotid, as well as the presence of collateral flow distal to the involved carotid, are important pieces of information. Conditioned recommendation & Moderate level of evidence (Persky et al., 2002)

5- Combined with a balloon occlusion test, catheter angiography can help determine the feasibility of carotid sacrifice during surgery if needed. Conditioned recommendation & Moderate level of evidence (Duffis, E.J. et al., 2012)

6-The goal of embolization should be to reduce the amount of tumor blush by approximately 80% or more. Conditioned recommendation & Moderate level of evidence (Tasar M & Yetiser S, 2004 and White JB et al., 2008)

7- Despite added resources used for embolization procedures compared with resection alone, the benefits of embolization may still be cost-effective. Conditioned recommendation & Moderate level of evidence (Dean BL et al., 1994)

8- Surgical resection should be carried out 1-8 days after embolization in order to maximize the benefits of the embolization procedure. Conditioned recommendation & Moderate level of evidence (Duffis, E.J. et al., 2012)

H. VENOUS SINUS STENTING PROCEDURE

1-  Idiopathic intracranial hypertension may be caused by significant bilateral venous sinus stenoses shown by MRV studies. Conditioned recommendation & Low level of evidence (Farb RI et al., 2003)

2- Endovascular venous stenting may improve visual deficits. There is insufficient evidence to determine role of endovascular approach in restoration of venous outflow in cerebral venous stenosis. Conditioned recommendation & very low level of evidence (Lee, S.-K. et al., 2018)

3- Endovascular therapy may be considered in patients with clinical deterioration or persistent symptoms despite adequate medical therapy. Conditioned recommendation & very low level of evidence (Lee, S.-K. et al., 2018)

1- A procedure note should be completed for all patients. It should summarize the findings of the study, its major technical aspects, and any immediate complications. The report should be available for review by the referring physician in a timely manner. Strong recommendation & High level of evidence (Wojak, J.C. et al., 2015)

2- All patients should be at bed rest and observed for indicators of procedural complications in the initial postprocedural period. Strong recommendation & High level of evidence (ACR-ASNR-SIR-SNIS Practice Parameter, 2021)

3- During the initial postprocedural period an experienced licensed provider should periodically monitor the puncture site and the status of the distal vascular distribution. Strong recommendation & High level of evidence (ACR-ASNR-SIR-SNIS Practice Parameter, 2021)