How to Treat Peripheral Arteriovenous Malformations

Arteriovenous malformations (AVMs) are direct communications between primitive reticular networks of dysplastic vessels that have failed to mature into capillary vessels. Based on angiographic findings, peripheral AVMs can be classified into six types: type I, type IIa, type IIb, type IIc, type IIIa, and type IIIb. Treatment strategies vary with the types. Type I is treated by embolizing the fistula between the artery and the vein with coils. Type II (IIa, IIb, and IIc) AVM is treated as follows: first, reduce the blood flow velocity in the venous segment of the AVM with coils; second, perform ethanol embolotherapy of the residual shunts. Type IIIa is treated by transarterial catheterization of the feeding arteries and injection of diluted ethanol. Type IIIb is treated by transarterial or direct puncture approaches. A high concentration of ethanol is injected through the transarterial catheter or direct puncture needle. When the fistula is large, coil insertion is required to reduce the amount of ethanol. Type I and type II AVMs showed the best clinical results; type IIIb showed a satisfactory response rate. However, type IIIa showed the poorest response rate, either alone or in combination with other types. Clinical success can be achieved by using different treatment strategies for different angiographic AVM types.     

Endovascular Treatment of Arteriovenous Malformations of the Head and Neck: Focus on the Yakes Classification and Outcomes

PurposeTo evaluate endovascular treatment of head and neck arteriovenous malformations (AVMs) based on the Yakes AVM classification and correlate treatment approach with clinical and angiographic outcomes.Materials and MethodsA retrospective single-center study was performed in patients who underwent endovascular treatment of head and neck AVMs between January 2005 and December 2017. Clinical and operative records, imaging, and postoperative courses of patients were reviewed. Clinical stage was determined according to the Schobinger classification. AVM architecture and treatment approaches were determined according to the Yakes classification. Primary outcomes were clinical and angiographic treatment success rates and complication rates, with analysis according to the Yakes classification.ResultsA total of 29 patients (15 females) were identified, with a mean age of 30.6 years. Downgrading of the Schobinger clinical classification was achieved in all patients. Lesions included 8 Yakes type IIa, 5 type IIb, 1 type IIIa and IIIb, and 14 type IV. Lesions were treated using an intra-arterial, nidal, or transvenous approach, using ethanol and liquid embolic agents. Arteriovenous shunt eradication of >90% was achieved in 22 of 28 patients (79%), including 9 of 13 (69%) of Yakes type IV lesions and 13 of 15 (87%) of the other types. There were 5 significant complications in 79 procedures (6%), including 4 of 50 (8%) in Yakes type IV lesions.ConclusionsSchobinger stage was downgraded in all patients. Arteriovenous shunt eradication of >90% was achieved in most patients. Yakes type IV lesions required more sessions, and shunt eradication was higher in the Yakes II and III groups.     

Liquid Embolic Agents for Endovascular Embolization: Evaluation of an Established (Onyx) and a Novel (PHIL) Embolic Agent in an In Vitro AVM Model

BACKGROUND AND PURPOSE:Embolization plays a key role in the treatment of arteriovenous malformations. The aim of this study was to evaluate an established (Onyx) and a novel (precipitating hydrophobic injectable liquid [PHIL]) liquid embolic agent in an in vitro AVM model.MATERIALS AND METHODS:An AVM model was integrated into a circuit system. The artificial nidus (subdivided into 28 honeycomb-like sections) was embolized with Onyx 18 (group Onyx; n = 8) or PHIL 25 (group PHIL; n = 8) with different pause times between the injections (30 and 60 seconds, n = 4 per study group) by using a 1.3F microcatheter. Procedure times, number of injections, embolization success (defined as the number of filled sections of the artificial nidus), volume of embolic agent, and frequency and extent of reflux and draining vein embolization were assessed.RESULTS:Embolization success was comparable between Onyx and PHIL. Shorter pause times resulted in a significantly higher embolization success for PHIL (median embolization score, 28 versus 18; P = .011). Compared with Onyx, lower volumes of PHIL were required for the same extent of embolization (median volume per section of the artificial nidus, 15.5 versus 3.6 μL; P < .001).CONCLUSIONS:While the embolization success was comparable for Onyx and PHIL, pause time had a considerable effect on the embolization success in an in vitro AVM model. Compared with Onyx, lower volumes of PHIL were required for the same extent of embolization.

Arteriovenous malformations are complex vascular structures composed of feeding arteries, an intervening network of small pathologic blood vessels (the so-called nidus), and draining veins. The lack of an intervening capillary bed allows high-flow arteriovenous shunting of blood. While AVMs can occur throughout the entire body, cerebral AVMs are of particular relevance due to their ability to cause impairing neurologic symptoms and their considerable risk of hemorrhage.¹Alone or in combination with microneurosurgery and stereotactic radiation therapy, embolization plays an important role in the management of cerebral AVMs.² The aim of AVM embolization is complete filling of the nidus, while unwanted reflux into the feeding arteries should be minimized and premature embolization of the draining veins should be avoided.³A wide variety of embolic agents has been and is currently used for embolization of AVMs. At present, the liquid embolic agents (LEAs) ethylene-vinyl alcohol copolymer (EVOH) and n-butyl cyanoacrylate are used most frequently.⁴ Although the embolization results have improved since the introduction of EVOH-based LEAs with rates of complete obliteration ranging from 16% to 100%, the success rate of AVM embolization, especially for complex AVMs, is not yet satisfying.^2,3 Currently, new LEAs are being introduced to improve embolization features, such as embolization efficacy, intraprocedural handling, and control. Furthermore, their use should improve fluoroscopic visibility and reduce artifacts in postinterventional imaging.The aim of this study was to evaluate an established EVOH-based embolic agent and a novel copolymer-based embolic agent in an in vitro AVM model.     

Treatment Outcomes of Embolization for Peripheral Arteriovenous Malformations

PurposeTo evaluate treatment outcomes of embolization for peripheral arteriovenous malformations (AVMs) in a tertiary referral center where ethanol is the primary agent of choice.MethodsA retrospective study was performed of 93 patients (median age, 31 years; range, 2–66 years) with peripheral AVMs treated with embolization (n = 442; median, 2 per patient; range, 1–82) between January 2010 and July 2016. Ethanol was used in most cases (n = 428; 97%). AVMs were classified as type I (n = 3), type II (n = 57), type IIIa (n = 5), type IIIb (n = 15), and type IV (n = 13) according to the Yakes classification system. Effectiveness of embolization was based on AVM devascularization on angiography: 100% (total), 90%–99% (near-total), 70%–90% (substantial), 30%–70% (partial), and 0%–30% (failure). Complications were graded according to the Society of Interventional Radiology classification.ResultsIn 69% of patients, 70%–100% devascularization was achieved. Total and near-total occlusion of the nidus were more often achieved in AVMs of types I and IIIa (both 100%) than in AVMs of types II, IIIb, and IV (56%, 67%, and 39%, respectively; P = .019). A total of 109 complications were identified: 101 minor (22.9%) and 8 major (1.8%). Major complications included wounds (n = 5), false aneurysm (n = 1), finger contracture (n = 1), and severe pain (n = 1) requiring therapy. The patient complication risk was significantly affected by the number of procedures (relative risk = 2.0; P < .001). Age, AVM location, and angioarchitecture type did not significantly affect complication risk.ConclusionsAVM embolization resulted in 70%–100% devascularization in 69% of patients, with few major complications. This study indicates that the type of AVM angioarchitecture affects the number of procedures needed and the achievability of AVM devascularization.     

Endovascular treatment of intracranial arteriovenous malformations with onyx: technical aspects

BACKGROUND AND PURPOSE: We report our experiences in the treatment of intracranial arteriovenous malformations (AVMs) with Onyx embolization before neuro- or radiosurgery, focusing on the embolization technique with Onyx. METHODS: Ninety-three patients (40 women and 53 men, mean age 38 years) with 94 intracranial AVMs with a mean volume of 9.2 mL were embolized with Onyx. The following features of all AVMs were evaluated before the treatment: type of nidus and shunt, draining veins, and feeding arteries. RESULTS: Complete obliteration rates were 20% at the end of all embolization steps and 53% after embolization and surgery. In 21% of patients the final control angiography is not yet available (after surgery 9%, after radiosurgery 12%). In 4% of patients, radiosurgery was planned due to a persistent arteriovenous shunt. The injection of Onyx resulted in high occlusion rates (volume reduction >90%) when the AVM was in a supratentorial and cortical location, the nidus was compact and plexiform, and when there was a small number of supplying (direct) feeders and one superficial draining vein. Access device-related complications (stuck catheter, vessel perforation) occurred during the embolization of 220 feeding arteries in 6% of patients, with all such instances having had no clinical consequences. CONCLUSION: With knowledge of the morphologic characteristics of AVMs that are suitable for a treatment with Onyx, high occlusion rates and low complication rates in treating a small number of feeders are feasible. Superselective intranidal or perinidal catheter positions and slow, controlled injections that protect the draining veins make the therapy safe even in complex AVMs and critical locations.     

Ethanol Embolotherapy of Vascular Malformations: Clinical Outcomes at a Single Center

PurposeTo retrospectively evaluate the results of endovascular therapy of vascular malformations principally treated with ethanol embolization at a single center.Materials and MethodsFrom May 1999 to December 2012, 46 patients (28 female, 18 male) with vascular malformations (31 venous malformations, 15 arteriovenous malformations [AVMs]) throughout the body (nine upper extremity, 31 lower extremity, and six truncal) who underwent ethanol embolization were studied and followed up. Demographic factors, clinical findings, imaging data, and patient-reported changes in symptoms were collected and analyzed. Follow-up data were obtained by office visits, repeat imaging, and telephone contact.ResultsTwenty-four patients (52.2%) were considered cured, 12 (26.1%) showed improvement, and 10 (21.7%) had no change or showed worsening. Similar rates of cure or improvement were seen for AVMs and venous malformations (P = 0.67). Lesion location, depth, and size were not associated with differences in outcomes (P = .87, P = .37, and P = .61, respectively). Type 1 and type 2 AVMs were cured more often than other AVM types. The overall complication rate was 24% (11 of 46 patients). Minor complications were seen in six individuals (13%), and major complications developed in five patients (11%).ConclusionsEthanol embolization of vascular malformations produces good outcomes, with control or relief of symptoms in a majority of patients.     

Efficacy and Safety of Transvenous Embolization of Type II Renal Arteriovenous Malformations with Coils

PurposeTo evaluate the efficacy and safety of transvenous coil embolization of the venous sac for type II renal arteriovenous malformation (AVM).Materials and MethodsA retrospective review was conducted of 8 patients (5 women and 3 men; mean age, 57 years; age range, 41–69 years) who underwent transvenous coil embolization for type II congenital renal AVM at 5 different hospitals between 2012 and 2018. Additional intra-arterial ethanol injection was performed if shunt flow persisted after venous sac coiling. Technical success was defined as complete occlusion of shunt flow with coil embolization. Clinical success was defined as no symptom recurrence during the follow-up period. The renal parenchymal infarction rate was measured on computed tomography (CT), and procedure-related complications were reviewed.ResultsNine sessions of embolization were performed for 8 patients. The mean venous sac size was 24 mm (range, 10–39 mm), and a mean of 14 micro and/or micro-detachable coils (range, 3–50) were used. The technical success rate was 88% (7 of 8) using coil embolization. One patient (12%) required additional ethanol injection to complete occlusion of the shunt flow and had a less than 10% parenchymal infarction on follow-up CT. No procedure-related complications or recurrences occurred during a mean clinical follow-up period of 20.8 months (range, 4.7–76.6 months).ConclusionsTransvenous coil embolization of type II renal AVM showed an 88% technical success rate. One patient (12%) showed less than 10% renal parenchymal infarction after additional ethanol injection. No additional complications or recurrences occurred during the follow-up period.     

Evaluation of 4D Vascular Flow and Tissue Perfusion in Cerebral Arteriovenous Malformations: Influence of Spetzler-Martin Grade,Clinical Presentation,and AVM Risk Factors

BACKGROUND AND PURPOSE:The role of intracranial hemodynamics in the pathophysiology and risk stratification of brain AVMs remains poorly understood. The purpose of this study was to assess the influence of Spetzler-Martin grade, clinical history, and risk factors on vascular flow and tissue perfusion in cerebral AVMs.MATERIALS AND METHODS:4D flow and perfusion MR imaging was performed in 17 patients with AVMs. Peak velocity and blood flow were quantified in AVM feeding and contralateral arteries, draining veins, and the straight sinus. Regional perfusion ratios (CBF, CBV, and MTT) were calculated between affected and nonaffected hemispheres.RESULTS:Regarding flow parameters, high-grade AVMs (Spetzler-Martin grade of >2) demonstrated significantly increased peak velocity and blood flow in the major feeding arteries (P < .001 and P = .004) and straight sinus (P = .003 and P = .012) and increased venous draining flow (P = .001). The Spetzler-Martin grade significantly correlated with cumulative feeding artery flow (r = 0.85, P < .001) and draining vein flow (r = 0.80, P < .001). Regarding perfusion parameters, perinidal CBF and CBV ratios were significantly lower (P < .001) compared with the remote ratios and correlated negatively with cumulative feeding artery flow (r = −0.60, P = .014 and r = −0.55, P = .026) and draining vein flow (r = −0.60, P = .013 and r = −0.56, P = .025). Multiple regression analysis revealed no significant association of AVM flow or perfusion parameters with clinical presentation (rupture and seizure history) and AVM risk factors.CONCLUSIONS:Macrovascular flow was significantly associated with increasing Spetzler-Martin grade and correlated with perinidal microvascular perfusion in cerebral AVMs. Future longitudinal studies are needed to evaluate the potential of comprehensive cerebral flow and perfusion MR imaging for AVM risk stratification.

Cerebral arteriovenous malformations are associated with an increased risk of intracranial hemorrhage, accounting for 2%–4% of all hemorrhagic strokes annually.¹ Previous studies have demonstrated the potential risk of hemorrhage following AVM embolization, presumably due to acute alterations in AVM or cerebral hemodynamics.² However, the Spetzler-Martin grade (SMG), widely used for surgical risk stratification in cerebral AVMs, does not provide insight into local or global hemodynamics.³ Quantitative assessment of AVM feeding and draining flow, combined with whole-brain tissue perfusion, can potentially characterize both AVM macro- and microvascular pathophysiology. In addition, the relationships between quantitative AVM hemodynamic parameters and the SMG or clinical history (rupture/seizures) and other risk factors (eg, presence of flow-induced aneurysms or venous stenosis, deep AVM location, and single or deep venous drainage) remain unclear.In this study, a comprehensive MR imaging and analysis protocol based on 4D flow and DSC perfusion MR imaging was applied for the characterization of 3D AVM macrovascular flow and microvascular brain tissue perfusion. 4D flow MR imaging can measure the 3-directional velocity field with full volumetric coverage of the vessels of interest.^4,5 Previous studies have shown that 4D flow MR imaging is highly promising in the evaluation of intracranial hemodynamics in cerebral AVMs.^6–8 To gain additional information on the impact of AVMs on cerebral tissue perfusion, we used DSC PWI based on a fast spin-echo EPI acquisition during the first pass of contrast agent through the brain vasculature to quantify microvascular perfusion biomarkers.^9,10 The AVM nidus has relatively low resistance and thus often causes high-flow transnidal shunts, which may result in hypoperfusion in the cerebral parenchyma immediately adjacent to AVMs. However, this so-called “steal effect” with diversion of blood from the adjacent tissue to the AVM nidus is still controversial, and it is unclear whether it should be considered a mechanism for the clinical presentation of cerebral AVMs.¹¹The purpose of this study was to quantitatively evaluate macrovascular flow in AVM arterial and venous networks and microvascular perfusion of the peripheral cerebral parenchyma. We investigated relationships between these quantitative hemodynamic parameters and SMG classification followed by correlation with various AVM symptomatic and anatomic risk factors.     

Spontaneous Intramuscular Hematomas of the Abdomen and Pelvis: A New Multilevel Algorithm to Direct Transarterial Embolization and Patient Management

Purpose

To report our experience using a multilevel patient management algorithm to direct transarterial embolization (TAE) in managing spontaneous intramuscular hematoma (SIMH).

Materials and Methods

From May 2006 to January 2014, twenty-seven patients with SIMH had been referred for TAE to our Radiology department. Clinical status and coagulation characteristics of the patients are analyzed. An algorithm integrating CT findings is suggested to manage SIMH. Patients were classified into three groups: Type I, SIMH with no active bleeding (AB); Type II, SIMH with AB and no muscular fascia rupture (MFR); and Type III, SIMH with MFR and AB. Type II is furthermore subcategorized as IIa, IIb and IIc. Types IIb, IIc and III were considered for TAE. The method of embolization as well as the material been used are described. Continuous variables are presented as mean ± SD. Categorical variables are reported as percentages. Technical success, clinical success, complications and 30-day mortality (d30 M) were analyzed.

Results

Two patients (7.5%) had Type IIb, four (15%) Type IIc and 21 (77.5%) presented Type III. The detailed CT and CTA findings, embolization procedure and materials used are described. Technical success was 96% with a complication rate of 4%. Clinical success was 88%. The bleeding-related thirty-day mortality was 15% (all with Type III).

Conclusion

TAE is a safe and efficient technique to control bleeding that should be considered in selected SIMH as soon as possible. The proposed algorithm integrating CT features provides a comprehensive chart to select patients for TAE.

Level of Evidence

4.

     

Embolization of cerebral arteriovenous malformations with silk: histopathologic changes and hemorrhagic complications.

PURPOSETo evaluate the safety of silk as an embolic agent for preoperative embolization of cerebral arteriovenous malformations (AVMs) by assessing the histopathologic changes and hemorrhagic complications associated with its use.METHODSHistopathologic specimens, medical records, and radiologic records of 73 patients with AVMs embolized with silk (alone or in combination with other agents) were reviewed retrospectively. Forty-eight histologic specimens obtained at surgery were analyzed for inflammatory responses and compared with the time interval between embolization and surgery. Postembolization angiograms were assessed for vasculitis and CT scans were reviewed for evidence of hemorrhage after embolization.RESULTSThere was no angiographic evidence of vasculitis. Histologic evidence of vasculitis was absent or mild in 92% of cases and histologic evidence of perivascular inflammation was absent or mild in 73% of cases. The frequency of histologic changes associated with vasculitis, perivascular inflammation, and vessel necrosis varied with the time interval between embolization and AVM resection. Intracranial hemorrhage, as a direct complication of silk use, occurred in one patient. Another patient had subarachnoid hemorrhage 24 hours after embolization, caused by rupture of a posteroinferior cerebellar artery aneurysm. Intraventricular high-density material appeared on routine postembolization CT scans in two other patients who had intraventricular AVM extension. This high-density material was thought to be contrast extravasation from intrinsically leaky AVM nidus vessels and not frank hemorrhage.CONCLUSIONEmbolization of AVMs with silk does not result in marked inflammation or increased hemorrhagic complications as compared with other agents.     

Exceptional multiplicity of cerebral arteriovenous malformations associated with hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome).

PURPOSETo describe the clinical and imaging features of seven patients with hereditary hemorrhagic telangiectasia and an exceptional number of cerebral arteriovenous malformations (AVMs).METHODSOne hundred thirty-six patients from a dedicated hereditary hemorrhagic telangiectasia clinic were screened systematically for cerebral AVMs by means of MR imaging. Thirty-one were found to have abnormalities suggestive of a vascular malformation. Eighteen of these 31 patients subsequently underwent diagnostic cerebral angiography.RESULTSOf the 18 patients who had cerebral angiography, all were found to have at least one AVM and seven were found to have three or more AVMs. The number of cerebral AVMs detected ranged from three to nine. At angiography, the AVMs varied in size from 3 to 25 mm in maximal dimension and consisted of a poorly defined plexiform nidus that typically had a single arterial feeding pedicle and a single draining vein. The two largest AVMs (20- and 25-mm nidus, respectively) contained intranidal aneurysms. Treatment included embolization, surgical excision, or follow-up management.CONCLUSIONSMultiple cerebral AVMs are associated with hereditary hemorrhagic telangiectasia and further highlight the uniqueness of central nervous system involvement by this systemic angiodysplasia. MR imaging can underestimate the number and size of cerebral AVMs; therefore, catheter angiography is necessary to establish the extent of central nervous system involvement in this disorder.     

Absolute Ethanol Embolization Combined with Surgical Resection of Scalp Arteriovenous Malformations: Interim Results

Purpose

To assess treatment methods, interim results, and complications of absolute ethanol embolization combined with surgical resection of scalp arteriovenous malformations (AVMs).

Combined Treatment of Brain AVMs with Use of Onyx Embolization followed by Radiosurgery

BACKGROUND AND PURPOSE:The treatment of cerebral AVMs is complex, reliant on interventions such as embolization, surgery, and radiosurgery, or a combination of these modalities. To date, treatment with the embolic agent Onyx, followed by radiosurgery, has not been evaluated. The goal of this study was to evaluate the safety and efficacy of this combination in a homogeneous, monocentric series.MATERIALS AND METHODS:From April 2003 to June 2008, a total of 20 patients (11 women and 9 men; age range, 10–55 years) were treated for AVMs with Onyx embolization followed by radiosurgery. AVM sizes were <3 cm in 7 patients and ≥3 cm in 13 patients. Modalities and complications of the procedure were analyzed as well as the long-term clinical and anatomic outcomes (2–5 years after treatment).RESULTS:Of 17 patients evaluated by DSA after radiosurgery, 10 (58.8%) were observed to have complete occlusion of the AVM nidus. Complete occlusion was observed in 5 (71.4%) of 7 Spetzler-Martin grade I–II AVMs and in 5 (50.0%) of 10 Spetzler-Martin grade III–IV AVMs. Complete occlusion was observed in 4 (80.0%) of 5 AVMs of <3 cm and 6 (50.0%) of 12 AVMs of >3 cm. One of 20 patients had significant worsening of clinical status (mRS ≥2) at long-term follow-up.CONCLUSIONS:In this preliminary series, the safety and efficacy of combined treatment by Onyx embolization followed by radiosurgery are quite satisfactory, with a low rate of clinical complications (5.0%) and a 58.8% rate of complete obliteration of the AVM.

Cerebral AVMs are associated with significant morbidity and mortality related to intracerebral hemorrhage, seizures, and progressive neurologic decline.¹ The treatment of cerebral AVMs can be quite complicated, and indication for treatment in some clinical situations is controversial (eg, for asymptomatic AVMs). Moreover, several modalities of treatment are available (surgery, radiosurgery, and embolization), and these modalities can be used in combination for some AVMs.Several techniques are available for embolization, dependent on the embolization agent used and technique of microcatheterization. For many years, embolization with n-BCA has been standard clinical practice for the treatment of brain AVMs. In the last 10 years, n-BCA has been progressively replaced by Onyx (ev3, Irvine, California), a copolymer that precipitates when coming into contact with blood.^2–5 The progression of Onyx when injected into a brain AVM follows a lavalike flow pattern and is not associated with the risks of gluing the distal portion of the microcatheter as when using n-BCA. Onyx injections can be more prolonged and controlled compared with n-BCA, making it possible to occlude larger portions of the nidus during each injection.The combination of embolization and radiosurgery is often used in the treatment of brain AVMs; however, the effectiveness of this combination remains controversial. Some series have suggested that embolization before radiosurgery was associated with lower obliteration rates and worse outcomes.^6,7 Several mechanisms have been suggested to explain lower obliteration rates, including recanalization of the nidus after embolization, enhanced angiogenesis after embolization (as demonstrated in animal models), difficulty in delineation of the nidus after embolization, and beam attenuation by the liquid embolization material.In most studies dedicated to the combination therapy of embolization followed by radiosurgery for the treatment of brain AVMs, particles or glue were used as the embolization agent.^6,8,9 To our knowledge, no study to date has evaluated embolization with Onyx followed by radiosurgery. To very precisely evaluate the combined therapy of Onyx embolization and radiosurgery, we conducted a monocentric, retrospective study, with all patients having very homogeneous modalities of treatment with embolization and radiosurgery.     

Intraoperative Neuromonitoring during Peripheral Arteriovenous Malformation Embolization

PurposeTo evaluate whether intraoperative neuromonitoring (IONM), including pre-embolization lidocaine injection challenge (“provocative testing”) is associated with reduced risk of irreversible nerve injury during embolization of peripheral arteriovenous malformations (AVMs).Materials and MethodsMedical records of patients with peripheral AVMs who underwent embolotherapy with IONM with provocative testing between 2012 and 2021 were reviewed retrospectively. Data collected included patient demographic characteristics, AVM location and size, embolic agent used, IONM signal changes after lidocaine and embolic agent injections, postprocedural adverse events, and clinical outcomes. Decisions regarding whether embolization would proceed at specific locations were based on IONM findings after the lidocaine challenge and as embolization proceeded.ResultsA cohort of 17 patients (mean age, 27 years ± 19; 5 women) who underwent 59 image-guided embolization procedures with adequate IONM data was identified. No permanent neurologic deficits occurred. Transient neurologic deficits were observed in 3 patients (4 sessions), comprising skin numbness (2 patients), extremity weakness (1 patient), and extremity weakness and numbness (1 patient). All neurologic deficits resolved by postoperative day 4 without additional treatment.ConclusionsIONM, including provocative testing, during AVM embolization may minimize potential nerve injury.     

Pelvic arteriovenous malformation treated by superselective transcatheter venous and arterial embolization

We describe a rare case of hematuria and hemospermia associated with pelvic arteriovenous malformation (AVM) in a male patient treated by transcatheter embolization. Understanding AVM hemodynamics contributes to the elucidation of its pathology and improves the outcome of embolization. In the present case, multiple arteriolar components shunted to the initial part of a single dominant outflow vein. Superselective embolization of a draining vein and feeding artery with an n-butyl cyanoacrylate/lipiodol mixture and polyvinyl alcohol particles was effective in terms of shunt disappearance and minimizing the need for subsequent arterial embolization.     

The efficacy of particulate embolization combined with stereotactic radiosurgery for treatment of large arteriovenous malformations of the brain.

PURPOSETo evaluate the efficacy of combined particulate embolization and single-stage stereotactic radiosurgery in the treatment of large arteriovenous malformations (AVMs) of the brain.METHODSTwenty-four patients with large brain AVMs (diameter > 3.0 cm; volume > 14 cm3), who had previously undergone particulate embolization and stereotactic radiosurgery, were retrospectively evaluated 2 or more years after radiosurgery.RESULTSIn 12 (50%) of these patients there was complete AVM obliteration, comparing favorably with a 58% obliteration rate in a group of AVMs having a 4- to 10-cm3 volume, treated by radiosurgery alone. Recanalization of embolized, but not radiated, AVM segments was identified in 3 (12%) patients. However, long-term occlusion was demonstrated in the embolized portions of most AVMs subsequently treated by radiosurgery. Complications included 1 (4%) patient with a mild upper extremity paresis after radiosurgery and 2 (8%) patients with transient neurologic deficits after embolization.CONCLUSIONCombined embolization and stereotactic radiosurgery was more efficacious than radiosurgery alone for large brain AVMs. Recanalization after embolization did occur but was a relatively minor cause of treatment failure.     

Complication risk of endovascular embolization for cerebral arteriovenous malformation

ObjectiveThe embolic agents currently used for the treatment of AVMs are n-butyl cyanoacrylate (NBCA) and ethylene-vinyl alcohol copolymer (ONYX). The purpose of this study was to examine the overall NBCA and ONYX embolization-related complication rate.MethodsWe retrospectively reviewed 147 consecutive patients with cerebral AVMs treated mainly with endovascular NBCA and ONYX embolization. Demographics, including age, sex, presenting symptoms, and angiographic factors including AVM size, deep venous drainage, and involvement of eloquent cortex were recorded. Number of pedicles embolized, the obliteration rate, and any complications were recorded. Complications were classified as the following: bleeding and ischemic complications. The ischemic complications were also classified as transient neurologic deficit, and permanent deficits. Modified Rankin Scale (mRS) scores were collected pre- and postembolization on all patients. Univariate regression analysis of determinants of complications was performed.ResultsWe reviewed 147 patients with BAVM (58.5% male; mean age ± SD at treatment: 27.5 ± 11.1years) treated with endovascular embolization. Two hundred twenty embolization, 144 NBCA and 76 ONYX embolizations were performed. Complete obliteration of BAVMs were achieved in 29 patients (19.7%). Additional gamma-knife radiosurgery were performed for 32 (21.8%) patients. There were 5 Spetzler–Martin grade I (3.4%), 20 grade II (13.6%), 54 grade III (36.7%), 44 grade IV (30%), and 24 grade V (16.3%) AVMs. There were a total of 7 (4.8% per patient, 3.2% per procedure) complications. There were bleeding complications in 2 patients (1.4% per patient, 0.9% per procedure), transient neurologic deficits in 4 (2.7% per patient, 1.8% per procedure) and 1 permanent deficit (0.7% per patient, 0.5% per procedure). Of the 147 patients, 141 (95.9%) were mRS 0–2, 6 (4.1%) were mRS = 3 at discharge. Univariate analysis of risk factors for embolic agent showed that ONYX was not significantly associated with complications (X² = 0.3, P > 0.5).ConclusionsEmbolization of brain AVMs is safe, 95.9% of patients had excellent or good outcomes at discharge after AVM embolization using liquid embolic agents, with a complication rate of 4.8%. ONYX embolization was not associated a higher rate of complications comparing with NBCA embolization.     

DSA对脑动静脉畸形出血的预测分析

目的:探讨脑动静脉畸形(AVM)血管造影形态与出血关系,预测脑动静脉畸形(AVM)出血的危险性。方法:回顾性分析104例数字减影脑血管畸形资料。结果:穿支动脉供血、单支引流和深部引流、小病灶及位于基底节和后颅窝者易出血。结论:通过观察脑动静脉畸形(AVM)供血动脉(类型)、大小、位置、引流静脉数目及通畅情况,可以对脑动静脉畸形(AVM)的出血情况进行预测。     

Treatment of arteriovenous malformations of the brain with combined embolization and stereotactic radiosurgery: results after 1 and 2 years

Seven patients with large arteriovenous malformations (AVMs) of the brain were selected for combined therapy with particulate embolization, followed by radiosurgery of the residual nidus. The goal of embolization was to reduce the patient nidus to a size that facilitated successful stereotactic radiosurgery. Angiograms obtained 1 and 2 years after radiosurgery were evaluated for changes in nidus size, flow rate, and feeding and draining vessels. One year after stereotactic radiosurgery, one AVM was angiographically undetectable. Three other AVMs demonstrated a volume reduction of greater than 50%, in addition to decreased shunt speed and altered angioarchitecture at 1-year follow-up. At 2-year follow-ups, two of seven AVMs were cured, and an additional two of seven had a greater than 98% reduction in nidus volume. Although one patient experienced a transient deficit from embolotherapy, none of our patients suffered a new neurologic deficit or a hemorrhage during the follow-up period. Our data support the efficacy of combined embolotherapy and radiosurgery for definitive therapy of selected large AVMs of the brain.     

Embolization of Congenital Renal Arteriovenous Malformations Using Ethanol and Coil Depending on Angiographic Types

Purpose

To evaluate effectiveness and safety of embolization of congenital renal arteriovenous malformations (AVMs) using ethanol and/or coil according to angiographic type.