Arteriovenous Malformations Obliteration Research Articles

Arteriovenous Malformations-Associated Epilepsy in Pediatrics.

Seizures are the second most common presentation of cerebral arteriovenous malformations (AVMs); pediatric patients are more likely to develop AVM-associated epilepsy. We examined the role of multimodality AVM treatment in pediatric AVM-associated epilepsy to characterize long-term epilepsy outcomes. A retrospective chart review identified pediatric patients with AVM-associated epilepsy seen at our institution from 2005 to 2018. Variables measured included demographic and descriptive data. Primary outcomes included seizure freedom, seizure control, and functional outcomes. Of 105 pediatric patients with AVMs, 18 had AVM-related epilepsy. Thirteen underwent surgical resection, of which 6 underwent preoperative embolization. Twelve (92.31%) had complete resection; one (7.69%) with residual underwent redo craniotomy with subsequent complete resection. All had radiographic cure at most recent follow-up, with no recurrence seen during length of follow-up (mean 2.17 years, SD 1.40, range 0.25-4.41). Eight (61.54%) experienced seizure freedom postoperatively; 12 (92.31%) were modified Engel Class I at last follow-up. Five patients underwent treatment without open surgical resection, with conservative management (3, 60%) or endovascular embolization (2, 40%). None in our cohort underwent radiosurgery. Of those embolized, one had complete AVM obliteration and two had partial obliteration. Four of the 5 patients (80%) treated without open surgery achieved seizure freedom. Long-term outcomes of AVM-related epilepsy are poorly characterized in children. We found that in addition to improved AVM outcomes regarding obliteration, treatment of residual, and recurrence, pediatric patients undergoing surgical AVM treatment had improved AVM-associated epilepsy outcomes, with 61.54% achieving seizure freedom and 92.31% classified as modified Engel Class I seizure control.

Comparison of cerebral AVMs in patients undergoing surgical resection with and without prior endovascular embolization

Aim Brain arteriovenous malformations (AVMs) are congenital anomalies that present as intracranial hemorrhage or epilepsy. AVMs often remain clinically silent for extended periods. Although AVM treatment methods are controversial, three treatment strategies are usually combined or applied alone: surgical removal, embolization and stereotactic radiosurgery. We compared clinical and radiological outcomes in intracranial AVM patients treated via surgical resection with and without prior embolization. Materials and methods Patients who did (30 patients) and did not (30 patients) undergo endovascular embolization before surgical resection at the İzmir Katip Çelebi University Atatürk Training and Research Hospital Neurosurgery Clinic from 2011 to 2019 were included in this retrospective, cohort study. Symptoms at diagnosis, comorbidities and clinical (AVM and Spetzler-Martin grade) and morphological characteristics were assessed. Results A mean one-year follow-up assessed outcomes using the modified Rankin score, and imaging studies assessed AVM obliteration post-procedure. Mean operation times for surgical resection with and without embolization were 166.50 ± 32.02 and 204.47 ± 26.66 min, respectively. Mean patient hospitalization periods for surgical resection with and without embolization were 8.43 ± 3.60 and 12.00 ± 5.51 days, respectively. Conclusion Among patients who underwent surgical resection, significant operation time and hospitalization time differences were observed in favor of patients who underwent embolization, indicating that preoperative embolization is a safe and beneficial method for treating ruptured and non-ruptured AVMs.

Systematic Review and Meta-Analysis of the Dose-Response and Risk Factors for Obliteration of Arteriovenous Malformations Following Radiosurgery: An Update Based on the Last 20 Years of Published Clinical Evidence

ABSTRACT BACKGROUND Intracranial arteriovenous malformation (AVM) is a congenital lesion that can potentially lead to devastating consequences if not treated. Many institutional cohort studies have reported on the outcomes after radiosurgery and factors associated with successful obliteration in the last few decades. OBJECTIVE To quantitatively assess the dose-response relationship and risk factors associated with AVM obliteration using a systematic review and meta-analysis approach. METHODS Data were extracted from reports published within the last 20 yr. The dose-response fit for obliteration as a function of marginal dose was performed using inverse-variance weighting. Risk factors for AVM obliteration were assessed by combining odds ratios from individual studies using inverse-variance weighting. RESULTS The logistic model fit showed a clear association between higher marginal dose and higher rates of obliteration. There appeared to be a difference in the steepness in dose-response when comparing studies with patients treated using Gamma Knife radiosurgery (Elekta), compared to linear accelerators (LINACs), and when stratifying studies based on the size of treated AVMs. In the risk-factor analysis, AVM obliteration rate decreases with larger AVM volume or AVM diameter, higher AVM score or Spetzler-Martin (SM) grade, and prior embolization, and increases with compact AVM nidus. No statistically significant associations were found between obliteration rate and age, sex, prior hemorrhage, prior aneurysm, and location eloquence. CONCLUSION A marginal dose above 18 Gy was generally associated with AVM obliteration rates greater than 60%, although lesion size, AVM score, SM grade, prior embolization, and nidus compactness all have significant impact on AVM obliteration rate.

Stereotactic Radiosurgery With Versus Without Embolization for Brain Arteriovenous Malformations.

Prior comparisons of brain arteriovenous malformations (AVMs) treated using stereotactic radiosurgery (SRS) with or without embolization were inherently flawed, due to differences in the pretreatment nidus volumes. To compare the outcomes of embolization and SRS, vs SRS alone for AVMs using pre-embolization malformation features. We retrospectively reviewed International Radiosurgery Research Foundation AVM databases from 1987 to 2018. Patients were categorized into the embolization and SRS (E+SRS) or SRS alone (SRS-only) cohorts. The 2 cohorts were matched in a 1:1 ratio using propensity scores. Primary outcome was defined as AVM obliteration. Secondary outcomes were post-SRS hemorrhage, all-cause mortality, radiologic and symptomatic radiation-induced changes (RIC), and cyst formation. The matched cohorts each comprised 101 patients. Crude AVM obliteration rates were similar between the matched E+SRS vs SRS-only cohorts (48.5%vs 54.5%; odds ratio=0.788, P=.399). Cumulative probabilities of obliteration at 3, 4, 5, and 6 yr were also similar between the E+SRS (33.0%, 46.4%, 56.2%, and 60.8%, respectively) and SRS-only (32.9%, 46.2%, 56.0%, and 60.6%, respectively) cohorts (subhazard ratio (SHR)=1.005, P=.981). Cumulative probabilities of radiologic RIC at 3, 4, 5, and 6 yr were lower in the E+SRS (25.0%, 25.7%, 26.7%, and 26.7%, respectively) vs SRS-only (45.3%, 46.2%, 47.8%, and 47.8%, respectively) cohort (SHR=0.478, P=.004). Symptomatic and asymptomatic embolization-related complication rates were 8.3% and 18.6%, respectively. Rates of post-SRS hemorrhage, all-cause mortality, symptomatic RIC, and cyst formation were similar between the matched cohorts. This study refutes the prevalent notion that AVM embolization negatively affects the likelihood of obliteration after SRS.

Embolization of Brain Arteriovenous Malformations With Versus Without Onyx Before Stereotactic Radiosurgery.

Embolization of brain arteriovenous malformations (AVMs) using ethylene-vinyl alcohol copolymer (Onyx) embolization may influence the treatment effects of stereotactic radiosurgery (SRS) differently than other embolysates. To compare the outcomes of pre-SRS AVM embolization with vs without Onyx through a multicenter, retrospective matched cohort study. We retrospectively reviewed International Radiosurgery Research Foundation AVM databases from 1987 to 2018. Embolized AVMs treated with SRS were selected and categorized based on embolysate usage into Onyx embolization (OE+SRS) or non-Onyx embolization (NOE+SRS) cohorts. The 2 cohorts were matched in a 1:1 ratio using de novo AVM features for comparative analysis of outcomes. The matched cohorts each comprised 45 patients. Crude AVM obliteration rates were similar between the matched OE+SRS vs NOE+SRS cohorts (47%vs 51%; odds ratio [OR]=0.837, P=.673). Cumulative probabilities of obliteration were also similar between the OE+SRS vs NOE+SRS cohorts (subhazard ratio=0.992, P=.980). Rates of post-SRS hemorrhage, all-cause mortality, radiation-induced changes, cyst formation, and embolization-associated complications were similar between the matched cohorts. Sensitivity analysis for AVMs in the OE+SRS cohort embolized with Onyx alone revealed a higher rate of asymptomatic embolization-associated complications in this subgroup compared to the NOE+SRS cohort (36%vs 15%; OR=3.297, P=.034), but the symptomatic complication rates were similar. Nidal embolization using Onyx does not appear to differentially impact the outcomes of AVM SRS compared with non-Onyx embolysates. The embolic agent selected for pre-SRS AVM embolization should reflect both the experience of the neurointerventionalist and target of endovascular intervention.

Commentary: Improved Cerebral Arteriovenous Malformation Obliteration With 3-Dimensional Rotational Digital Subtraction Angiography for Radiosurgical Planning: A Retrospective Cohort Study.

Commentary: Improved Cerebral Arteriovenous Malformation Obliteration With 3-Dimensional Rotational Digital Subtraction Angiography for Radiosurgical Planning: A Retrospective Cohort Study.

Experience of intracranial arteriovenous malformations endovascular treatment with advanced techniques and non-adhesive liquid embolic agents using

Objective ‒ to evaluate the possibility of endovascular embolization using non-adhesion of liquid embolic agents as monotherapy for the treatment of cerebral arteriovenous malformations (AVM), its reliability and safety.Materials and methods. examination and gradual endovascular treatment of 64 patients (120 sessions) using non-adhesive liquid embolic agents. Patients were divided into two groups: with ruptured AVM (n = 43) and with unruptured (n = 21). In all cases of unruptured AVM, signs indicating an increased risk of rupture of the AVM were verified.Results. the average decrease in volume after embolization was 79.5 % (up to 50 % ‒ in 7 cases, 50‒75 % ‒ in 14, 75‒99 % ‒ in 29). Complete exclusion of AVM was achieved in 14 (22 %) patients. On average, 2–3 feeders were embolized on the AVM to achieve such results. It was found that the number of feeders was directly proportional to the number of sessions required. Malformations of small size (up to 3 cm) often managed to close in one session. Clinically significant deficiency (2 on the modified Rankin scale) after embolization was found in 2 (3 %) patients. The deficit regressed within 7 days. The angiographic frequency of complete obliteration of AVM at the end of all embolization procedures was 22 % (14 AVM).Conclusions. knowledge of the angioarchitectural characteristics of AVM, which are suitable for the treatment with liquid embolic agents, and their careful selection allow to achieve a high frequency of occlusion with a low frequency of complications. The use of superselective intranidal or perinidal positions of the catheter, slow controlled injections that protect the draining veins, the gradual embolization make the therapy safer.

Does the Diffuseness of the Nidus Affect the Outcome of Stereotactic Radiosurgery in Patients with Unruptured Cerebral Arteriovenous Malformations?

Background: We proposed an algorithm to automate the components within the identification of components within the nidus of cerebral arteriovenous malformations (AVMs) which may be used to analyze the relationship between its diffuseness and treatment outcomes following stereotactic radiosurgery (SRS). Objectives: to determine the impact of the diffuseness of the AVM nidus on SRS outcomes. Methods: This study conducted regular follow-ups of 209 patients with unruptured AVMs who underwent SRS. The diffuseness of the AVM nidus was estimated by quantifying the proportions of vascular nidal component, brain parenchyma, and cerebrospinal fluid in T2-weighted MRIs. We used Cox regression analysis to characterize the association between nidal diffuseness and treatment outcomes in terms of obliteration rate and radiation-induced change (RICs) rate following SRS. Results: The median AVM volume was 20.7 cm³. The median duration of imaging follow-up was 51 months after SRS. The overall AVM obliteration rate was 68.4%. RICs were identified in 156 of the 209 patients (74.6%). The median proportions of the nidus of AVM and brain parenchyma components within the prescription isodose range were 30.2 and 52.2%, respectively. Cox regression multivariate analysis revealed that the only factor associated with AVM obliteration rate after SRS was AVM volume. However, a larger AVM volume (>20 mL) and a larger proportion of brain parenchyma (>50%) within the prescription isodose range were both correlated with a higher RIC rate following SRS. Conclusions: The diffuseness of the nidus indeed appears to affect the RIC rate following SRS in patients with unruptured AVMs.

Magnetic Resonance Perfusion Changes of Arteriovenous Malformations Treated with Stereotactic Radiosurgery

The latency period from stereotactic radiosurgery (SRS) to obliteration of arteriovenous malformations (AVM) requires continuous imaging surveillance. Magnetic resonance (MR) perfusion is promising for noninvasive monitoring of AVMs after SRS. We studied longitudinal MR perfusion changes of brain AVMs treated with SRS. Consecutive patients treated for brain AVMs using SRS who had MR perfusion imaging studies performed before and at least once after SRS were studied. We estimated ipsilateral/contralateral brain hemisphere ratios of MR perfusion indexes, including regional cerebral blood flow (rCBF) and relative cerebral blood volume (rCBV), in the AVM nidus, perinidal region, and remote anterior and posterior brain regions. Eleven patients (6 women; median age, 21 years) underwent SRS (median prescription dose, 18 Gy; range, 12-20 Gy) for brain AVMs (median Spetzler-Martin grade 2 and median volume 4.6 mL). Before the SRS, rCBV and rCBF ratios were significantly higher in the AVM nidus compared with other investigated brain regions (P < 0.001). Median time from SRS to the first and last post-SRS MR perfusion studies was 8 and 35 months, respectively. There was a statically significant decrease of rCBV (P= 0.043) and rCBF (P= 0.036) ratios in the AVM nidus, but not other brain regions, during post-SRS follow-up. There is a gradual decrease of rCBV and rCBF in the AVM nidus after SRS. MR perfusion imaging is promising for monitoring of hemodynamic changes of AVMs after SRS. Larger studies investigating clinical value of MR perfusion imaging for AVMs after SRS are warranted.

Surgical management of pediatric rolandic arteriovenous malformations: a single-center case series.

Pediatric rolandic arteriovenous malformations (AVMs) present a treatment challenge given the lifetime risk of hemorrhage, rehemorrhage, and associated long-term morbidity. Microsurgical resection has been recommended as the optimal treatment for AVMs in general, but there is no dedicated literature on the outcomes of resection of pediatric rolandic AVMs. Here, the study objective was to review the outcomes of microsurgical resection of pediatric rolandic AVMs in the modern era, together with the utilization of surgical adjuncts including navigation, intraoperative angiography, and neurophysiological monitoring. The authors performed a retrospective review of patients 18 years of age and younger with cerebral AVMs microsurgically treated between January 2000 and May 2016 at The Hospital for Sick Children. Only those patients with an AVM whose nidus was located within the rolandic region were analyzed. A descriptive analysis was performed to identify patient demographics, preoperative AVM characteristics, and postoperative obliteration rates and neurological complications. A total of 279 AVMs were evaluated in the study period. Twenty-three of these AVMs were rolandic, and the median age in the 11 microsurgically treated cases was 11 years (range 1-17 years). AVM hemorrhage was the most common presentation, occurring in 8 patients (73%). Lesions were either Spetzler-Martin grade II (n = 8, 73%) or grade III (n = 3, 27%). The postoperative obliteration rate of AVMs was 100%. The mean imaging follow-up duration was 33 months (range 5-164 months). There was no documented recurrence of an AVM during follow-up. One patient developed a transient postoperative hemiparesis, while another patient developed right fingertip hyperesthesia. Microsurgical resection of rolandic pediatric AVMs yields excellent AVM obliteration with minimal neurological morbidity in selected patients. The incorporation of surgical adjuncts, including neurophysiological monitoring and neuronavigation, allows accurate demarcation of functional cortex and enables effective resection.

Brain arteriovenous malformations: A review of natural history, pathobiology, and interventions.

Brain arteriovenous malformations (AVMs) are anomalous direct shunts between cerebral arteries and veins that convalesce into a vascular nidus. The treatment strategies for AVMs are challenging and variable. Intracranial hemorrhage and seizures comprise the most common presentations of AVMs. However, incidental AVMs are being diagnosed with increasing frequency due to widespread use of noninvasive neuroimaging. The balance between the estimated cumulative lifetime hemorrhage risk vs the risk of intervention is often the major determinant for treatment. Current management options include surgical resection, embolization, stereotactic radiosurgery (SRS), and observation. Complete nidal obliteration is the goal of AVM intervention. The risks and benefits of interventions vary and can be used in a combinatorial fashion. Resection of the AVM nidus affords high rates of immediate obliteration, but it is invasive and carries a moderate risk of neurologic morbidity. AVM embolization is minimally invasive, but cure can only be achieved in a minority of lesions. SRS is also minimally invasive and has little immediate morbidity, but AVM obliteration occurs in a delayed fashion, so the patient remains at risk of hemorrhage during the latency period. Whether obliteration can be achieved in unruptured AVMs with a lower risk of stroke or death compared with the natural history of AVMs remains controversial. Over the past 5 years, multicenter prospective and retrospective studies describing AVM natural history and treatment outcomes have been published. This review provides a contemporary and comprehensive discussion of the natural history, pathobiology, and interventions for brain AVMs.

Clinico-Radiologic Outcomes After Stereotactic Radiosurgery for Patients with Complex High-Risk Multiple Arteriovenous Malformations

The present study aims to define the outcome and risks of patients with multiple arteriovenous malformations (AVMs) treated by stereotactic radiosurgery (SRS). We retrospectively analyzed the records of 1232 patients with AVMs who underwent SRS at our center between 1987 and 2017. We identified 10 patients who had SRS for multiple AVMs (total of 25). Eight patients presented with intracranial hemorrhage before SRS. Four patients had hereditary hemorrhagic telangiectasia. A Spetzler-Martin grade I AVM was diagnosed in 11 AVMs, grade II in 7, grade III in 6, and grade IV in 1 AVM. The median maximum diameter was 12 mm, the median target volume was 1.1 cm3, and the median margin dose was 20 Gy. Twenty-four AVMs were treated with single-session SRS, and 1 AVM was treated with volume-staged SRS. The angiographic complete obliteration rate of each AVM was 18.2%, 58.0%, and 66.4% at 3, 5, and 7 years, respectively. The angiographic complete obliteration rate of all treated AVMs in each patient was 11.1%, 51.4%, and 51.4% at 3, 5, and 7 years, respectively. In multivariate analysis, higher marginal dose (≥18 Gy, P= 0.031) was significantly associated with complete obliteration of AVMs. After obliteration of all their AVMs was confirmed no patient bled. Patients with complex multiple AVMs often presented with a brain hemorrhage. Reduction in bleeding risk after SRS requires complete obliteration that is more likely if the initial AVM margin dose is ≥18 Gy for each AVM.

Radiosurgery for Unruptured Intervention-Naïve Pediatric Brain Arteriovenous Malformations.

Long-term data regarding stereotactic radiosurgery (SRS) as a standalone therapy for unruptured pediatric brain arteriovenous malformations (AVMs) are incompletely defined. To evaluate, in a multicenter, retrospective cohort study, the outcomes after SRS for unruptured, intervention-naïve pediatric AVMs. To retrospectively analyze the International Radiosurgery Research Foundation pediatric AVM database from 1987 to 2018. Pediatric patients with unruptured, previously untreated AVMs who underwent SRS were included. The primary endpoint was a composite of hemorrhagic stroke, death, or permanently symptomatic radiation-induced changes. The study cohort comprised 101 patients (mean follow-up 80.8 mo). The primary endpoint occurred in 14%, comprising hemorrhagic stroke, death, and permanent radiation-induced changes in 6%, 3%, and 8%, respectively. Estimated probabilities of the primary endpoint were 5.2%, 10.8%, and 23.0% at 2, 5, and 10 yr, respectively. Estimated probabilities of AVM obliteration at 5 and 10 yr were 64% and 82%, respectively. Single SRS treatment (P=.007) and higher margin dose (P=.005) were predictors of obliteration. Subgroup analysis of Spetzler-Martin grade I-III AVMs estimated primary endpoint probabilities of 3.7%, 8.4%, and 18.7% at 2, 5, and 10 yr, respectively. Treatment of unruptured, intervention-naïve AVMs in the pediatric population with SRS carries an approximately 2% annual risk of morbidity and mortality, which appears to plateau after 10 yr. The poorly described natural history of pediatric AVMs renders any comparison of SRS vs conservative management imperfect.

Commentary: Stagnant Venous Outflow Predicts Brain Arteriovenous Malformation Obliteration After Gamma Knife Radiosurgery Without Prior Intervention.

Correspondence: Tony J. C. Wang, MD, |622 West 168th St, CHONY Basement North, New York, NY 11032, USA. Email: [email protected]

Biologically effective dose and prediction of obliteration of unruptured arteriovenous malformations treated by upfront Gamma Knife radiosurgery: a series of 149 consecutive cases.

Arteriovenous malformations (AVMs) present no pathologic tissue, and radiation dose is confined in a clear targeted volume. The authors retrospectively evaluated the role of the biologically effective dose (BED) after Gamma Knife radiosurgery (GKRS) for brain AVMs. A total of 149 consecutive cases of unruptured AVMs treated by upfront GKRS in Lille University Hospital, France, were included. The mean length of follow-up was 52.9 months (median 48, range 12-154 months). The primary outcome was obliteration, and the secondary outcome was complication appearance. The marginal dose was 24 Gy in a vast majority of cases (n = 115, 77.2%; range 18-25 Gy). The mean BED was 220.1 Gy2.47 (median 229.9, range 106.7-246.8 Gy2.47). The mean beam-on time was 32.3 minutes (median 30.8, range 9-138.7 minutes). In the present series, the mean radiation dose rate was 2.259 Gy/min (median 2.176, range 1.313-3.665 Gy/min). The Virginia score was 0 in 29 (19.5%), 1 in 61 (40.9%), 2 in 41 (27.5%), 3 in 18 (12.1%), and 4 in 0 (0%) patients, respectively. The mean Pollock-Flickinger score was 1.11 (median 1.52, range 0.4-2.9). Univariate (for obliteration and complication appearance) and multivariate (for obliteration only) analyses were performed. A total of 104 AVMs (69.8%) were obliterated at the last follow-up. The strongest predictor for obliteration was BED (p = 0.03). A radiosurgical obliteration score is proposed, derived from a fitted multivariable model: (0.018 × BED) + (1.58 × V12) + (-0.013689 × beam-on time) + (0.021 × age) - 4.38. The area under the receiver operating characteristic curve was 0.7438; after internal validation using bootstrap methods, it was 0.7088. No statistically significant relationship between radiation dose rate and obliteration was found (p = 0.29). Twenty-eight (18.8%) patients developed complications after GKRS; 20 (13.4%) of these patients had transient adverse radiological effects (perilesional edema developed). Predictors for complication appearance were higher prescription isodose volume (p = 0.005) and 12-Gy isodose line volume (V12; p = 0.001), higher Pollock-Flickinger (p = 0.02) and Virginia scores (p = 0.003), and lower beam-on time (p = 0.03). The BED was the strongest predictor of obliteration of unruptured AVMs after upfront GKRS. A radiosurgical score comprising the BED is proposed. The V12 appears as a predictor for both efficacy and toxicity. Beam-on time was illustrated as statistically significant for both obliteration and complication appearance. The radiation dose rate did not influence obliteration in the current analysis. The exact BED threshold remains to be established by further studies.

Update Onyx embolization for plexiform arteriovenous malformation: Ante-grade drifting technique.

The conventional arteriovenous malformation (AVM) Onyx embolization technique is the extrusion Onyx injection technique, with blood-flow control after a certain distance casting through the head end of the microcatheter. This method has elevated periprocedural AVM bleeding complications. In this study, the authors reported safety and efficacy of an updated ante-grade drifting Onyx injection for plexiform AVM embolization. Between January 2016 and December 2018, 101 consecutive patients with plexiform AVMs were treated with ante-grade drifting Onyx injection. The patients' clinical status was classified using the modified Rankin Scale (mRS). To measure associations, logistic univariate or multivariate regression analyses were used. Complete AVM obliteration was achieved in 51.2% (52/101) of patients. Two (2/101, 2.0%) arterial perforations occurred without causing neurological deficits. In univariate and multivariate logistic regression analyses, younger patient age (odds ratio (OR) = 1.06, 95% confidence interval (CI) 1.01-1.12, p = 0.014), haemorrhagic presentation at admission (OR = 7.14, 95% CI 1.52-33.33, p = 0.013) and low Spetzler-Martin grade (OR = 10.00, 95% CI 3.45-25.00, p < 0.001) were significantly correlated with complete obliteration. Pretreatment mRS was correlated with perforation complication (OR = 3.44, 95% CI 1.05-11.29, p = 0.041) in univariate logistic regression analysis but not in multivariate logistic regression analysis (OR = 2.956, 95%CI 0.745, 11.731, p = 0.123). Patients' clinical status was significantly improved after endovascular AVM embolization. With ante-grade drifting Onyx injection, it was possible to prevent serious bleeding complications and elevated complete embolization rate in plexiform AVMs. Younger patient age, haemorrhagic presentation at admission and low AVM Spetzler-Martin grade were significantly correlated with complete obliteration. Although there is not enough statistical power to show that the pretreatment mRS and the arterial perforation complication have a significant correlation, but its OR value is large, and there may be more data in the future to obtain further conclusion.

Stereotactic Radiosurgery for Brain Arteriovenous Malformations: Evaluation of Obliteration and Review of Associated Predictors

BackgroundHigh arteriovenous malformation (AVM) obliteration rates have been reported with stereotactic radiosurgery (SRS), and multiple factors have been found to be associated with AVM obliteration. These predictors have been inconsistent throughout studies. We aimed to analyze our experience with linear accelerator (LINAC)-based SRS for brain AVMs, evaluate outcomes, assess factors associated with AVM obliteration and review the various reported predictors of AVM obliteration. MethodsElectronic medical records were retrospectively reviewed to identify consecutive patients with brain AVMs treated with SRS over a 27-year period with at least 2 years of follow-up. Logistic regression analysis was performed to identify factors associated with AVM obliteration. ResultsOne hundred twenty-eight patients with 142 brain AVMs treated with SRS were included. Mean age was 34.4 years. Fifty-two percent of AVMs were associated with a hemorrhage before SRS, and 14.8% were previously embolized. Mean clinical and angiographic follow-up times were 67.8 months and 58.6 months, respectively. The median Spetzler-Martin grade was 3. Mean maximal AVM diameter was 2.8 cm and mean AVM target volume was 7.4 cm3 with a median radiation dose of 16 Gy. Complete AVM obliteration was achieved in 80.3%. Radiation-related signs and symptoms were encountered in 32.4%, only 4.9% of which consisted of a permanent deficit. Post-SRS AVM-related hemorrhage occurred in 6.3% of cases. In multivariate analysis, factors associated with AVM obliteration included younger patient age (P = .019), male gender (P = .008), smaller AVM diameter (P = .04), smaller AVM target volume (P = .009), smaller isodose surface volume (P = .005), a higher delivered radiation dose (P = .013), and having only one major draining vein (P = .04). ConclusionsAVM obliteration with LINAC-based radiosurgery was safe and effective and achieved complete AVM obliteration in about 80% of cases. The most prominent predictors of AVM success included AVM size, AVM volume, radiation dose, number of draining veins and patient age.

N-butyl cyanoacrylate transvenous arteriovenous malformation embolization with arterial balloon assistance: Defining parameters for a transvenous approach as a potential upfront treatment option in managing cerebral arteriovenous malformations

Complete obliteration of arteriovenous malformations (AVMs) using a transvenous approach as the primary and stand-alone treatment modality has been increasingly considered as a useful endovascular approach in the treatment of AVMs. AVMs are typically treated with microsurgery, stereotactic radiosurgery, endovascular embolization, or some combination of the three methods. Preservation of the draining vein is a key requisite common to all treatment modalities. Transvenous embolization (TVE) is conventionally not recommended as a stand-alone treatment for the vast majority of AVMs and has been thought to be best indicated when traditional approaches are considered less safe and when specific evaluation criteria are met. We report a case of a 35-year-old asymptomatic male diagnosed with a small intracranial AVM adjacent to the right motor strip which was managed utilizing this approach. We employed endovascular embolization via a transvenous approach with arterial balloon assistance due to the small size of the nidus, eloquent location, en passage arterial supply proximal to the venous varix, and a single draining vein from the fistula. This case illustrates the selective indications and technical nuances of TVE approach in managing AVMs as a potential upfront treatment option. When patients harbor AVMs with specific angio-architectural findings as outlined, TVE utilizing Onyx or N-butyl cyanoacrylate can be safely performed as a primary treatment modality.

Clinical outcome following cerebral AVM hemorrhage.

A significant difference exists between the published results reporting the clinical outcome following brain arteriovenous malformation (AVM) ruptures. Information about the outcome following hemorrhage in an AVM population treated with radiosurgery could provide additional information to assess the risk of mortality and morbidity following an AVM hemorrhage. Clinical outcome was studied in 383 patients, the largest patient population yet studied, who suffered from a symptomatic hemorrhage after Gamma Knife® surgery (GKS) but before confirmed AVM obliteration. The impact of different patient, AVM, and treatment parameters on the clinical outcome was analyzed. The aim was to generate outcome predictions by comparing our data to and combining them with earlier published results. No relation was found between clinical outcome and treatment parameters, indicating that the results are applicable also on untreated AVMs. Twenty-one percent of the patients died, 45% developed or experienced worsening of neurological sequelae, and 35% recovered completely after the hemorrhage. Old age was a predictor of poor outcome. Sex, AVM location, AVM volume, and history of prior hemorrhage did not influence the outcome. The mortality rate was comparable to earlier published prospective data, but higher than that found in retrospective studies. The mortality rates in earlier published retrospective series as well as in studies focusing on clinical outcome following AVM hemorrhage significantly underestimate the risk for a mortal outcome following an AVM hemorrhage. Based on our findings, an AVM rupture has around 20% likelihood to result in mortality, 45% likelihood to result in a minor or major deficit, and 35% likelihood of complete recovery. The findings are probably applicable also for AVM ruptures in general. The cumulative mortality and morbidity rates 25years after diagnosis were estimated to be around 40% in a patient with a patent AVM.

Gamma Knife Radiosurgery Followed by Flow-Reductive Embolization for Ruptured Arteriovenous Malformation.

Background: Aggressive treatment to achieve complete obliteration of brain arteriovenous malformation (AVM) is necessary in patients with a recent history of hemorrhage. The major drawback of Gamma knife radiosurgery (GKRS) alone for AVM is risk of bleeding during the latent period until the AVM occludes. At our center, patients who present with ruptured AVMs are frequently offered GKRS followed by embolization. The goal of this study was to compare outcomes of embolization for patients who have previously undergone GKRS for ruptured AVMs. Methods: A database including 150 GKRS for ruptured AVMs between November 2008 and October 2017 was reviewed. The embolized group was selected by including AVMs with post-GKRS embolization. The non-embolized group was defined as AVMs treated by GKRS alone. Outcomes including obliteration rate, incidence of repeat hemorrhage, and delayed cyst formation were compared between two groups. The predictive factors related to AVM obliteration and complications were analyzed. Results: The study consisted of 81 patients in the non-embolized group and 17 patients in the embolized group. Statistically significant differences were detected between the two groups with respect to age, Pollock-Flickinger score, Spetzler-Martin (SM) grade, eloquence of adjacent brain, and presence of aneurysms. The embolized group included more AVMs with larger median nidus volume. The predictive factors for the obliteration of ruptured AVMs were nidus volume, SM grade, Virginia Radiosurgery AVM Scale (VRAS), and Pollock-Flickinger score and for the subsequent hemorrhage were marginal dose, nidus volume, SM grade, VRAS, and Pollock-Flickinger score. The obliteration rates and complication rates after GKRS between groups were not significantly different. However, this study demonstrated statistically significant difference in the cumulative incidence of obliteration in AVMs with SM grade III and IV (p = 0.037). Conclusion: Although the current study demonstrated similar results in patients who underwent GKRS with and without embolization, the embolized group included more AVMs with larger nidus volume, higher SM grade, Pollock-Flickinger score, and aneurysm, which have a lower chance of obliteration and a higher probability of repeat hemorrhage. GKRS followed by embolization appears to be a beneficial approach for the treatment of ruptured AVMs that are at risk for obliteration failure and repeat hemorrhage during the latency period after single-session GKRS alone. Further studies involving a larger number of cases and continuous follow-up are necessary to confirm our conclusions.