Adverse radiation effects in volume-staged radiosurgery for large arteriovenous malformations: a multiinstitutional study

OBJECTIVE

The optimal treatment paradigm for large arteriovenous malformations (AVMs) is controversial. One approach is volume-staged stereotactic radiosurgery (VS-SRS). The authors previously reported efficacy of VS-SRS for large AVMs in a multiinstitutional cohort; here they focus on risk of symptomatic adverse radiation effects (AREs).

METHODS

This is a multicentered retrospective review of patients treated with a planned prospective volume staging approach to stereotactically treat the entire nidus of an AVM, with volume stages separated by intervals of 3-6 months. A total of 9 radiosurgical centers treated 257 patients with VS-SRS between 1991 and 2016. The authors evaluated permanent, transient, and total ARE events that were symptomatic.

RESULTS

Patients received 2-4 total volume stages. The median age was 33 years at the time of the first SRS volume stage, and the median follow-up was 5.7 years after VS-SRS. The median total AVM nidus volume was 23.25 cm3 (range 7.7-94.4 cm3), with a median margin dose per stage of 17 Gy (range 12-20 Gy). A total of 64 patients (25%) experienced an ARE, of which 19 were permanent. Rather than volume, maximal linear dimension in the Z (craniocaudal) dimension was associated with toxicity; a threshold length of 3.28 cm was associated with an ARE, with a 72.5% sensitivity and a 58.3% specificity. In addition, parietal lobe involvement for superficial lesions and temporal lobe involvement for deep lesions were associated with an ARE.

CONCLUSIONS

Size remains the dominant predictor of toxicity following SRS, but overall rates of AREs were lower than anticipated based on baseline features, suggesting that dose and size were relatively dissociated through volume staging. Further techniques need to be assessed to optimize outcomes.

Stereotactic Radiosurgery With Versus Without Embolization for Brain Arteriovenous Malformations

BACKGROUND

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.

OBJECTIVE

To compare the outcomes of embolization and SRS, vs SRS alone for AVMs using pre-embolization malformation features.

METHODS

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.

RESULTS

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.

CONCLUSION

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

BACKGROUND

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.

OBJECTIVE

To compare the outcomes of pre-SRS AVM embolization with vs without Onyx through a multicenter, retrospective matched cohort study.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Stereotactic radiosurgery with versus without prior Onyx embolization for brain arteriovenous malformations

OBJECTIVE

Investigations of the combined effects of neoadjuvant Onyx embolization and stereotactic radiosurgery (SRS) on brain arteriovenous malformations (AVMs) have not accounted for initial angioarchitectural features prior to neuroendovascular intervention. The aim of this retrospective, multicenter matched cohort study is to compare the outcomes of SRS with versus without upfront Onyx embolization for AVMs using de novo characteristics of the preembolized nidus.

METHODS

The International Radiosurgery Research Foundation AVM databases from 1987 to 2018 were retrospectively reviewed. Patients were categorized based on AVM treatment approach into Onyx embolization (OE) and SRS (OE+SRS) or SRS alone (SRS-only) cohorts and then propensity score matched in a 1:1 ratio. The primary outcome was AVM obliteration. Secondary outcomes were post-SRS hemorrhage, all-cause mortality, radiological and symptomatic radiation-induced changes (RICs), and cyst formation. Comparisons were analyzed using crude rates and cumulative probabilities adjusted for competing risk of death.

RESULTS

The matched OE+SRS and SRS-only cohorts each comprised 53 patients. Crude rates (37.7% vs 47.2% for the OE+SRS vs SRS-only cohorts, respectively; OR 0.679, p = 0.327) and cumulative probabilities at 3, 4, 5, and 6 years (33.7%, 44.1%, 57.5%, and 65.7% for the OE+SRS cohort vs 34.8%, 45.5%, 59.0%, and 67.1% for the SRS-only cohort, respectively; subhazard ratio 0.961, p = 0.896) of AVM obliteration were similar between the matched cohorts. The secondary outcomes of the matched cohorts were also similar. Asymptomatic and symptomatic embolization-related complication rates in the matched OE+SRS cohort were 18.9% and 9.4%, respectively.

CONCLUSIONS

Pre-SRS AVM embolization with Onyx does not appear to negatively influence outcomes after SRS. These analyses, based on de novo nidal characteristics, thereby refute previous studies that found detrimental effects of Onyx embolization on SRS-induced AVM obliteration. However, given the risks incurred by nidal embolization using Onyx, this neoadjuvant intervention should be used judiciously in multimodal treatment strategies involving SRS for appropriately selected large-volume or angioarchitecturally high-risk AVMs.

Stereotactic Radiosurgery for Cavernous Sinus Versus Noncavernous Sinus Dural Arteriovenous Fistulas: Outcomes and Outcome Predictors

BACKGROUND

Dural arteriovenous fistulas (DAVFs) can be categorized based on location.

OBJECTIVE

To compare stereotactic radiosurgery (SRS) outcomes between cavernous sinus (CS) and non-CS DAVFs and to identify respective outcome predictors.

METHODS

This is a retrospective study of DAVFs treated with SRS between 1988 and 2016 at 10 institutions. Patients' variables, DAVF characters, and SRS parameters were included for analyses. Favorable clinical outcome was defined as angiography-confirmed obliteration without radiological radiation-induced changes (RIC) or post-SRS hemorrhage. Other outcomes were DAVFs obliteration and adverse events (including RIC, symptomatic RIC, and post-SRS hemorrhage).

RESULTS

The overall study cohort comprised 131 patients, including 20 patients with CS DAVFs (15%) and 111 patients with non-CS DAVFs (85%). Rates of favorable clinical outcome were comparable between the 2 groups (45% vs 37%, P = .824). Obliteration rate after SRS was higher in the CS DAVFs group, even adjusted for baseline difference (OR = 4.189, P = .044). Predictors of favorable clinical outcome included higher maximum dose (P = .014) for CS DAVFs. Symptomatic improvement was associated with obliteration in non-CS DAVFs (P = .005), but symptoms improved regardless of whether obliteration was confirmed in CS DAVFs. Non-CS DAVFs patients with adverse events after SRS were more likely to be male (P = .020), multiple arterial feeding fistulas (P = .018), and lower maximum dose (P = .041).

CONCLUSION

After SRS, CS DAVFs are more likely to obliterate than non-CS ones. Because these 2 groups have different total predictors for clinical and radiologic outcomes after SRS, they should be considered as different entities.

Dose response and architecture in volume staged radiosurgery for large arteriovenous malformations: A multi-institutional study

BACKGROUND

Optimal treatment paradigm for large arteriovenous malformations (AVMs) is controversial. Volume-staged stereotactic radiosurgery (VS-SRS) provides an effective option for these high-risk lesions, but optimizing treatment for these recalcitrant and rare lesions has proven difficult.

METHODS

This is a multi-centered retrospective review of patients treated with a planned prospective volume staging approach to stereotactically treat the entire nidus of an AVM with volume stages separated by intervals of 3-6 months. A total of 9 radiosurgical centers treated 257 patients with VS-SRS between 1991 and 2016. We evaluated near complete response (nCR), obliteration, cure, and overall survival.

RESULTS

With a median age of 33 years old at the time of first SRS volume stage, patients received 2-4 total volume stages and a median follow up of 5.7 years after VS-SRS. The median total AVM nidus volume was 23.25 cc (range: 7.7-94.4 cc) with a median margin dose per stage of 17 Gy (range: 12-20 Gy). Total AVM volume, margin dose per stage, compact nidus, lack of prior embolization, and lack of thalamic location involvement were all associated with improved outcomes. Dose >/= 17.5 Gy was strongly associated with improved rates of nCR, obliteration, and cure. With dose >/= 17.5 Gy, 5- and 10-year cure rates were 33.7% and 76.8% in evaluable patients compared to 23.7% and 34.7% of patients with 17 Gy and 6.4% and 20.6% with <17 Gy per volume-stage (p = 0.004). Obliteration rates in diffuse nidus architecture with <17 Gy were particularly poor with none achieving obliteration compared to 32.3% with doses >/= 17 Gy at 5 years (p = 0.007). Comparatively, lesions with a compact nidus architecture exhibited obliteration rates at 5 years were 10.7% vs 9.3% vs 26.6% for dose >17 Gy vs 17 Gy vs >/=17.5 Gy.

CONCLUSION

VS-SRS is an option for upfront treatment of large AVMs. Higher dose was associated with improved rates of nCR, obliteration, and cure suggesting that larger volumetric responses may facilitate salvage therapy and optimize the chance for cure.

Hemorrhage risk of cerebral dural arteriovenous fistulas following Gamma Knife radiosurgery in a multicenter international consortium

OBJECTIVE

The authors performed a study to evaluate the hemorrhagic rates of cerebral dural arteriovenous fistulas (dAVFs) and the risk factors of hemorrhage following Gamma Knife radiosurgery (GKRS).

METHODS

Data from a cohort of patients undergoing GKRS for cerebral dAVFs were compiled from the International Radiosurgery Research Foundation. The annual posttreatment hemorrhage rate was calculated as the number of hemorrhages divided by the patient-years at risk. Risk factors for dAVF hemorrhage prior to GKRS and during the latency period after radiosurgery were evaluated in a multivariate analysis.

RESULTS

A total of 147 patients with dAVFs were treated with GKRS. Thirty-six patients (24.5%) presented with hemorrhage. dAVFs that had any cortical venous drainage (CVD) (OR = 3.8, p = 0.003) or convexity or torcula location (OR = 3.3, p = 0.017) were more likely to present with hemorrhage in multivariate analysis. Half of the patients had prior treatment (49.7%). Post-GRKS hemorrhage occurred in 4 patients, with an overall annual risk of 0.84% during the latency period. The annual risks of post-GKRS hemorrhage for Borden type 2-3 dAVFs and Borden type 2-3 hemorrhagic dAVFs were 1.45% and 0.93%, respectively. No hemorrhage occurred after radiological confirmation of obliteration. Independent predictors of hemorrhage following GKRS included nonhemorrhagic neural deficit presentation (HR = 21.6, p = 0.027) and increasing number of past endovascular treatments (HR = 1.81, p = 0.036).

CONCLUSIONS

Patients have similar rates of hemorrhage before and after radiosurgery until obliteration is achieved. dAVFs that have any CVD or are located in the convexity or torcula were more likely to present with hemorrhage. Patients presenting with nonhemorrhagic neural deficits and a history of endovascular treatments had higher risks of post-GKRS hemorrhage.

Stereotactic radiosurgery for arteriovenous malformations of the basal ganglia and thalamus: an international multicenter study

OBJECTIVE

Arteriovenous malformations (AVMs) of the basal ganglia (BG) and thalamus are associated with elevated risks of both hemorrhage if left untreated and neurological morbidity after resection. Therefore, stereotactic radiosurgery (SRS) has become a mainstay in the management of these lesions, although its safety and efficacy remain incompletely understood. The aim of this retrospective multicenter cohort study was to evaluate the outcomes of SRS for BG and thalamic AVMs and determine predictors of successful endpoints and adverse radiation effects.

METHODS

The authors retrospectively reviewed data on patients with BG or thalamic AVMs who had undergone SRS at eight institutions participating in the International Gamma Knife Research Foundation (IGKRF) from 1987 to 2014. Favorable outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation-induced changes (RICs). Multivariable models were developed to identify independent predictors of outcome.

RESULTS

The study cohort comprised 363 patients with BG or thalamic AVMs. The mean AVM volume and SRS margin dose were 3.8 cm3 and 20.7 Gy, respectively. The mean follow-up duration was 86.5 months. Favorable outcome was achieved in 58.5% of patients, including obliteration in 64.8%, with rates of post-SRS hemorrhage and permanent RIC in 11.3% and 5.6% of patients, respectively. Independent predictors of favorable outcome were no prior AVM embolization (p = 0.011), a higher margin dose (p = 0.008), and fewer isocenters (p = 0.044).

CONCLUSIONS

SRS is the preferred intervention for the majority of BG and thalamic AVMs. Patients with morphologically compact AVMs that have not been previously embolized are more likely to have a favorable outcome, which may be related to the use of a higher margin dose.

Evaluation of stereotactic radiosurgery for cerebral dural arteriovenous fistulas in a multicenter international consortium

OBJECTIVE

In this multicenter study, the authors reviewed the results obtained in patients who underwent Gamma Knife radiosurgery (GKRS) for dural arteriovenous fistulas (dAVFs) and determined predictors of outcome.

METHODS

Data from a cohort of 114 patients who underwent GKRS for cerebral dAVFs were compiled from the International Gamma Knife Research Foundation. Favorable outcome was defined as dAVF obliteration and no posttreatment hemorrhage or permanent symptomatic radiation-induced complications. Patient and dAVF characteristics were assessed to determine predictors of outcome in a multivariate logistic regression analysis; dAVF-free obliteration was calculated in a competing-risk survival analysis; and Youden indices were used to determine optimal radiosurgical dose.

RESULTS

A mean margin dose of 21.8 Gy was delivered. The mean follow-up duration was 4 years (range 0.5-18 years). The overall obliteration rate was 68.4%. The postradiosurgery actuarial rates of obliteration at 3, 5, 7, and 10 years were 41.3%, 61.1%, 70.1%, and 82.0%, respectively. Post-GRKS hemorrhage occurred in 4 patients (annual risk of 0.9%). Radiation-induced imaging changes occurred in 10.4% of patients; 5.2% were symptomatic, and 3.5% had permanent deficits. Favorable outcome was achieved in 63.2% of patients. Patients with middle fossa and tentorial dAVFs (OR 2.4, p = 0.048) and those receiving a margin dose greater than 23 Gy (OR 2.6, p = 0.030) were less likely to achieve a favorable outcome. Commonly used grading scales (e.g., Borden and Cognard) were not predictive of outcome. Female sex (OR 1.7, p = 0.03), absent venous ectasia (OR 3.4, p < 0.001), and cavernous carotid location (OR 2.1, p = 0.019) were predictors of GKRS-induced dAVF obliteration.

CONCLUSIONS

GKRS for cerebral dAVFs achieved obliteration and avoided permanent complications in the majority of patients. Those with cavernous carotid location and no venous ectasia were more likely to have fistula obliteration following radiosurgery. Commonly used grading scales were not reliable predictors of outcome following radiosurgery.

Effect of Advanced Age on Stereotactic Radiosurgery Outcomes for Brain Arteriovenous Malformations: A Multicenter Matched Cohort Study

BACKGROUND

The effect of age on adult brain arteriovenous malformation (AVM) outcomes after stereotactic radiosurgery (SRS) remains unclear. The aim of this study is to compare AVM outcomes between elderly (age ≥60 years) and nonelderly adult patients.

METHODS

We retrospectively reviewed pooled data comprising patients who underwent SRS for AVMs between 1987 and 2014 at 8 centers participating in the International Gamma Knife Research Foundation. Adult (age ≥18 years) patients with ≥12 months follow-up were dichotomized into elderly and nonelderly cohorts, and matched in a 1:1 ratio. Favorable outcome was AVM obliteration without permanent symptomatic radiation-induced changes (RIC) or post-SRS hemorrhage.

RESULTS

The study cohort consisted of 1845 patients (188 elderly vs. 1657 nonelderly) who met the inclusion criteria, and subsequent matching resulted in 181 patients in each cohort. In the matched cohorts, rates of obliteration (54.7% vs. 64.6%; P = 0.054) favorable outcome (51.4% vs. 61.3%; P = 0.056) were no different between the elderly and nonelderly cohorts. The rates of post-SRS hemorrhage (9.9% vs. 5.5%; P = 0.115), RIC (26.5% vs. 30.9%; P = 0.353), symptomatic RIC (9.4% vs. 9.4%; P = 1.000), and permanent symptomatic RIC (3.3% vs. 2.2%; P = 0.750) were also not significantly different between the elderly and nonelderly cohorts. Elderly patients with AVM did have a significantly higher rate of all-cause mortality (27.7% vs. 5.5%; P < 0.001).

CONCLUSIONS

Advanced age does not seem to significantly affect obliteration or complication rates after SRS for AVMs. Although the decision to recommend intervention for AVMs in the elderly population is multifactorial, SRS may be a viable modality when treatment is deemed appropriate.

Effect of treatment period on outcomes after stereotactic radiosurgery for brain arteriovenous malformations: an international multicenter study

OBJECTIVE

The role of and technique for stereotactic radiosurgery (SRS) in the management of arteriovenous malformations (AVMs) have evolved over the past four decades. The aim of this multicenter, retrospective cohort study was to compare the SRS outcomes of AVMs treated during different time periods.

METHODS

The authors selected patients with AVMs who underwent single-session SRS at 8 different centers from 1988 to 2014 with follow-up ≥ 6 months. The SRS eras were categorized as early (1988-2000) or modern (2001-2014). Statistical analyses were performed to compare the baseline characteristics and outcomes of the early versus modern SRS eras. Favorable outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation-induced changes (RICs).

RESULTS

The study cohort comprised 2248 patients with AVMs, including 1584 in the early and 664 in the modern SRS eras. AVMs in the early SRS era were significantly smaller (p < 0.001 for maximum diameter and volume), and they were treated with a significantly higher radiosurgical margin dose (p < 0.001). The obliteration rate was significantly higher in the early SRS era (65% vs 51%, p < 0.001), and earlier SRS treatment period was an independent predictor of obliteration in the multivariate analysis (p < 0.001). The rates of post-SRS hemorrhage and radiological, symptomatic, and permanent RICs were not significantly different between the two groups. Favorable outcome was achieved in a significantly higher proportion of patients in the early SRS era (61% vs 45%, p < 0.001), but the earlier SRS era was not statistically significant in the multivariate analysis (p = 0.470) with favorable outcome.

CONCLUSIONS

Despite considerable advances in SRS technology, refinement of AVM selection, and contemporary multimodality AVM treatment, the study failed to observe substantial improvements in SRS favorable outcomes or obliteration for patients with AVMs over time. Differences in baseline AVM characteristics and SRS treatment parameters may partially account for the significantly lower obliteration rates in the modern SRS era. However, improvements in patient selection and dose planning are necessary to optimize the utility of SRS in the contemporary management of AVMs.

Radiosurgery for Unruptured Brain Arteriovenous Malformations: An International Multicenter Retrospective Cohort Study

BACKGROUND

The role of intervention in the management of unruptured brain arteriovenous malformations (AVM) is controversial.

OBJECTIVE

To analyze in a multicenter, retrospective cohort study, the outcomes following radiosurgery for unruptured AVMs and determine predictive factors.

METHODS

We evaluated and pooled AVM radiosurgery data from 8 institutions participating in the International Gamma Knife Research Foundation. Patients with unruptured AVMs and ≥12 mo of follow-up were included in the study cohort. Favorable outcome was defined as AVM obliteration, no postradiosurgical hemorrhage, and no permanently symptomatic radiation-induced changes.

RESULTS

The unruptured AVM cohort comprised 938 patients with a median age of 35 yr. The median nidus volume was 2.4 cm 3 , 71% of AVMs were located in eloquent brain areas, and the Spetzler-Martin grade was III or higher in 57%. The median radiosurgical margin dose was 21 Gy and follow-up was 71 mo. AVM obliteration was achieved in 65%. The annual postradiosurgery hemorrhage rate was 1.4%. Symptomatic and permanent radiation-induced changes occurred in 9% and 3%, respectively. Favorable outcome was achieved in 61%. In the multivariate logistic regression analysis, smaller AVM maximum diameter ( P = .001), the absence of AVM-associated arterial aneurysms ( P = .001), and higher margin dose ( P = .002) were found to be independent predictors of a favorable outcome. A margin dose ≥ 20 Gy yielded a significantly higher rate of favorable outcome (70% vs 36%; P < .001).

CONCLUSION

Radiosurgery affords an acceptable risk to benefit profile for patients harboring unruptured AVMs. These findings justify further prospective studies comparing radiosurgical intervention to conservative management for unruptured AVMs.

Stereotactic radiosurgery for Spetzler-Martin Grade IV and V arteriovenous malformations: an international multicenter study

OBJECTIVE Due to the complexity of Spetzler-Martin (SM) Grade IV-V arteriovenous malformations (AVMs), the management of these lesions remains controversial. The aims of this multicenter, retrospective cohort study were to evaluate the outcomes after single-session stereotactic radiosurgery (SRS) for SM Grade IV-V AVMs and determine predictive factors. METHODS The authors retrospectively pooled data from 233 patients (mean age 33 years) with SM Grade IV (94.4%) or V AVMs (5.6%) treated with single-session SRS at 8 participating centers in the International Gamma Knife Research Foundation. Pre-SRS embolization was performed in 71 AVMs (30.5%). The mean nidus volume, SRS margin dose, and follow-up duration were 9.7 cm³, 17.3 Gy, and 84.5 months, respectively. Statistical analyses were performed to identify factors associated with post-SRS outcomes. RESULTS At a mean follow-up interval of 84.5 months, favorable outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation-induced changes (RIC) and was achieved in 26.2% of patients. The actuarial obliteration rates at 3, 7, 10, and 12 years were 15%, 34%, 37%, and 42%, respectively. The annual post-SRS hemorrhage rate was 3.0%. Symptomatic and permanent RIC occurred in 10.7% and 4% of the patients, respectively. Only larger AVM diameter (p = 0.04) was found to be an independent predictor of unfavorable outcome in the multivariate logistic regression analysis. The rate of favorable outcome was significantly lower for unruptured SM Grade IV-V AVMs compared with ruptured ones (p = 0.042). Prior embolization was a negative independent predictor of AVM obliteration (p = 0.024) and radiologically evident RIC (p = 0.05) in the respective multivariate analyses. CONCLUSIONS In this multi-institutional study, single-session SRS had limited efficacy in the management of SM Grade IV-V AVMs. Favorable outcome was only achieved in a minority of unruptured SM Grade IV-V AVMs, which supports less frequent utilization of SRS for the management of these lesions. A volume-staged SRS approach for large AVMs represents an alternative approach for high-grade AVMs, but it requires further investigation.

Stereotactic radiosurgery for cerebellar arteriovenous malformations: an international multicenter study

OBJECTIVE

Cerebellar arteriovenous malformations (AVMs) represent the majority of infratentorial AVMs and frequently have a hemorrhagic presentation. In this multicenter study, the authors review outcomes of cerebellar AVMs after stereotactic radiosurgery (SRS).

METHODS

Eight medical centers contributed data from 162 patients with cerebellar AVMs managed with SRS. Of these patients, 65% presented with hemorrhage. The median maximal nidus diameter was 2 cm. Favorable outcome was defined as AVM obliteration and no posttreatment hemorrhage or permanent radiation-induced complications (RICs). Patients were followed clinically and radiographically, with a median follow-up of 60 months (range 7–325 months).

RESULTS

The overall actuarial rates of obliteration at 3, 5, 7, and 10 years were 38.3%, 74.2%, 81.4%, and 86.1%, respectively, after single-session SRS. Obliteration and a favorable outcome were more likely to be achieved in patients treated with a margin dose greater than 18 Gy (p < 0.001 for both), demonstrating significantly better rates (83.3% and 79%, respectively). The rate of latency preobliteration hemorrhage was 0.85%/year. Symptomatic post-SRS RICs developed in 4.5% of patients (n = 7). Predictors of a favorable outcome were a smaller nidus (p = 0.0001), no pre-SRS embolization (p = 0.003), no prior hemorrhage (p = 0.0001), a higher margin dose (p = 0.0001), and a higher maximal dose (p = 0.009). The Spetzler-Martin grade was not found to be predictive of outcome. The Virginia Radiosurgery AVM Scale score (p = 0.0001) and the Radiosurgery-Based AVM Scale score (p = 0.0001) were predictive of a favorable outcome.

CONCLUSIONS

SRS results in successful obliteration and a favorable outcome in the majority of patients with cerebellar AVMs. Most patients will require a nidus dose of higher than 18 Gy to achieve these goals. Radiosurgical and not microsurgical scales were predictive of clinical outcome after SRS.

International multicenter cohort study of pediatric brain arteriovenous malformations. Part 1: Predictors of hemorrhagic presentation

OBJECTIVE Brain arteriovenous malformations (AVMs) are the most common cause of spontaneous intracranial hemorrhage in pediatric patients (age < 18 years). Since the cumulative lifetime risk of AVM hemorrhage is considerable in children, an improved understanding of the risk factors influencing hemorrhagic presentation may aid in the management of pediatric AVMs. The aims of this first of a 2-part multicenter, retrospective cohort study are to evaluate the incidence and determine the predictors of hemorrhagic presentation in pediatric AVM patients. METHODS The authors analyzed pooled AVM radiosurgery data from 7 institutions participating in the International Gamma Knife Research Foundation (IGKRF). Patients younger than 18 years at the time of radiosurgery and who had at least 12 months of follow-up were included in the study cohort. Patient and AVM characteristics were compared between unruptured and ruptured pediatric AVMs. RESULTS A total of 357 pediatric patients were eligible for analysis, including 112 patients in the unruptured and 245 patients in the ruptured AVM cohorts (69% incidence of hemorrhagic presentation). The annual hemorrhage rate prior to radiosurgery was 6.3%. Hemorrhagic presentation was significantly more common in deep locations (basal ganglia, thalamus, and brainstem) than in cortical locations (frontal, temporal, parietal, and occipital lobes) (76% vs 62%, p = 0.006). Among the factors found to be significantly associated with hemorrhagic presentation in the multivariate logistic regression analysis, deep venous drainage (OR 3.2, p < 0.001) was the strongest independent predictor, followed by female sex (OR 1.7, p = 0.042) and smaller AVM volume (OR 1.1, p < 0.001). CONCLUSIONS Unruptured and ruptured pediatric AVMs have significantly different patient and nidal features. Pediatric AVM patients who possess 1 or more of these high-risk features may be candidates for relatively more aggressive management strategies.

International multicenter cohort study of pediatric brain arteriovenous malformations. Part 2: Outcomes after stereotactic radiosurgery

OBJECTIVE Pediatric patients (age < 18 years) harboring brain arteriovenous malformations (AVMs) are burdened with a considerably higher cumulative lifetime risk of hemorrhage than adults. Additionally, the pediatric population was excluded from recent prospective comparisons of intervention versus conservative management for unruptured AVMs. The aims of this multicenter, retrospective cohort study are to analyze the outcomes after stereotactic radiosurgery for unruptured and ruptured pediatric AVMs. METHODS We analyzed and pooled AVM radiosurgery data from 7 participating in the International Gamma Knife Research Foundation. Patients younger than 18 years of age who had at least 12 months of follow-up were included in the study cohort. Favorable outcome was defined as AVM obliteration, no post-radiosurgical hemorrhage, and no permanently symptomatic radiation-induced changes (RIC). The post-radiosurgery outcomes of unruptured versus ruptured pediatric AVMs were compared, and statistical analyses were performed to identify predictive factors. RESULTS The overall pediatric AVM cohort comprised 357 patients with a mean age of 12.6 years (range 2.8-17.9 years). AVMs were previously treated with embolization, resection, and fractionated external beam radiation therapy in 22%, 6%, and 13% of patients, respectively. The mean nidus volume was 3.5 cm³, 77% of AVMs were located in eloquent brain areas, and the Spetzler-Martin grade was III or higher in 59%. The mean radiosurgical margin dose was 21 Gy (range 5-35 Gy), and the mean follow-up was 92 months (range 12-266 months). AVM obliteration was achieved in 63%. During a cumulative latency period of 2748 years, the annual post-radiosurgery hemorrhage rate was 1.4%. Symptomatic and permanent radiation-induced changes occurred in 8% and 3%, respectively. Favorable outcome was achieved in 59%. In the multivariate logistic regression analysis, the absence of prior AVM embolization (p = 0.001) and higher margin dose (p < 0.001) were found to be independent predictors of a favorable outcome. The rates of favorable outcome for patients treated with a margin dose ≥ 22 Gy vs < 22 Gy were 78% (110/141 patients) and 47% (101/216 patients), respectively. A margin dose ≥ 22 Gy yielded a significantly higher probability of a favorable outcome (p < 0.001). The unruptured and ruptured pediatric AVM cohorts included 112 and 245 patients, respectively. Ruptured AVMs had significantly higher rates of obliteration (68% vs 53%, p = 0.005) and favorable outcome (63% vs 51%, p = 0.033), with a trend toward a higher incidence of post-radiosurgery hemorrhage (10% vs 4%, p = 0.07). The annual post-radiosurgery hemorrhage rates were 0.8% for unruptured and 1.6% for ruptured AVMs. CONCLUSIONS Radiosurgery is a reasonable treatment option for pediatric AVMs. Obliteration and favorable outcomes are achieved in the majority of patients. The annual rate of latency period hemorrhage after radiosurgery for both ruptured and unruptured pediatric AVM patients conveys a significant risk until the nidus is obliterated.

A rare case of a vertebrojugular arteriovenous fistula: A case report and review of literature

Vertebrojugular fistulas have been described in the literature associated with blunt or penetrating injury and iatrogenic or spontaneous development. Its presentation may be broad and may include symptoms of radiculopathy, vertebrobasilar insufficiency, tinnitus, and bruit. However, so far, no direct cardiac complications had been reported. Here, we describe a case of an 86-year-old female who suffered a C5 vertebral fracture secondary to a ground-level fall that was initially treated conservatively due to the onset of new severe atrial fibrillation. However, the patient was later on taken to surgery due to progressive neurologic deterioration. Intraoperative complications led to the diagnosis of a vertebral-jugular fistula that was successfully embolized. The effective obliteration of the fistulae led to the recovery of both neurologic and cardiac symptoms.

Early versus late arteriovenous malformation responders after stereotactic radiosurgery: an international multicenter study

OBJECTIVE The goal of stereotactic radiosurgery (SRS) for arteriovenous malformation (AVM) is complete nidus obliteration, thereby eliminating the risk of future hemorrhage. This outcome can be observed within the first 18 months, although documentation of AVM obliteration can extend to as much as 5 years after SRS is performed. A shorter time to obliteration may impact the frequency and effect of post-SRS complications and latency hemorrhage. The authors' goal in the present study was to determine predictors of early obliteration (18 months or less) following SRS for cerebral AVM. METHODS Eight centers participating in the International Gamma Knife Research Foundation (IGKRF) obtained institutional review board approval to supply de-identified patient data. From a cohort of 2231 patients, a total of 1398 patients had confirmed AVM obliteration. Patients were sorted into early responders (198 patients), defined as those with confirmed nidus obliteration at or prior to 18 months after SRS, and late responders (1200 patients), defined as those with confirmed nidus obliteration more than 18 months after SRS. The median clinical follow-up time was 63.7 months (range 7-324.7 months). RESULTS Outcome parameters including latency interval hemorrhage, mortality, and favorable outcome were not significantly different between the 2 groups. Radiologically demonstrated radiation-induced changes were noted more often in the late responder group (376 patients [31.3%] vs 39 patients [19.7%] for early responders, p = 0.005). Multivariate independent predictors of early obliteration included a margin dose > 24 Gy (p = 0.031), prior surgery (p = 0.002), no prior radiotherapy (p = 0.025), smaller AVM nidus (p = 0.002), deep venous drainage (p = 0.039), and nidus location (p < 0.0001). Basal ganglia, cerebellum, and frontal lobe nidus locations favored early obliteration (p = 0.009). The Virginia Radiosurgery AVM Scale (VRAS) score was significantly different between the 2 responder groups (p = 0.039). The VRAS score was also shown to be predictive of early obliteration on univariate analysis (p = 0.009). For early obliteration, such prognostic ability was not shown for other SRS- and AVM-related grading systems. CONCLUSIONS Early obliteration (≤ 18 months post-SRS) was more common in patients whose AVMs were smaller, located in the frontal lobe, basal ganglia, or cerebellum, had deep venous drainage, and had received a margin dose > 24 Gy.

Stereotactic radiosurgery for Spetzler-Martin Grade III arteriovenous malformations: an international multicenter study

OBJECTIVE Because of the angioarchitectural diversity of Spetzler-Martin (SM) Grade III arteriovenous malformations (AVMs), the management of these lesions is incompletely defined. The aims of this multicenter, retrospective cohort study were to evaluate the outcomes after stereotactic radiosurgery (SRS) for SM Grade III AVMs and to determine the factors predicting these outcomes. METHODS The authors analyzed and pooled data from patients with SM Grade III AVMs treated with SRS at 8 institutions participating in the International Gamma Knife Research Foundation. Patients with these AVMs and a minimum follow-up length of 12 months were included in the study cohort. An optimal outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation-induced changes (RICs). Data were analyzed by univariate and multivariate regression analyses. RESULTS The SM Grade III AVM cohort comprised 891 patients with a mean age of 34 years at the time of SRS. The mean nidus volume, radiosurgical margin dose, and follow-up length were 4.5 cm³, 20 Gy, and 89 months, respectively. The actuarial obliteration rates at 5 and 10 years were 63% and 78%, respectively. The annual postradiosurgery hemorrhage rate was 1.2%. Symptomatic and permanent RICs were observed in 11% and 4% of the patients, respectively. Optimal outcome was achieved in 56% of the patients and was significantly more frequent in cases of unruptured AVMs (OR 2.3, p < 0.001). The lack of a previous hemorrhage (p = 0.037), absence of previous AVM embolization (p = 0.002), smaller nidus volume (p = 0.014), absence of AVM-associated arterial aneurysms (p = 0.023), and higher margin dose (p < 0.001) were statistically significant independent predictors of optimal outcome in a multivariate analysis. CONCLUSIONS Stereotactic radiosurgery provided better outcomes for patients with small, unruptured SM Grade III AVMs than for large or ruptured SM Grade III nidi. A prospective trial or registry that facilitates a comparison of SRS with conservative AVM management might further clarify the authors' observations for these often high-risk AVMs.

The fate of cranial neuropathy after flow diversion for carotid aneurysms

OBJECT

The authors sought to determine whether flow diversion with the Pipeline Embolization Device (PED) can approximate microsurgical decompression in restoring function after cranial neuropathy following carotid artery aneurysms.

METHODS

This multiinstitutional retrospective study involved 45 patients treated with PED across the United States. All patients included presented between November 2009 and October 2013 with cranial neuropathy (cranial nerves [CNs] II, III, IV, and VI) due to intracranial aneurysm. Outcome analysis included clinical and procedural variables at the time of treatment as well as at the latest clinical and radiographic follow-up.

RESULTS

Twenty-six aneurysms (57.8%) were located in the cavernous segment, while 6 (13.3%) were in the clinoid segment, and 13 (28.9%) were in the ophthalmic segment of the internal carotid artery. The average aneurysm size was 18.6 mm (range 4–35 mm), and the average number of flow diverters placed per patient was 1.2. Thirty-eight patients had available information regarding duration of cranial neuropathy prior to treatment. Eleven patients (28.9%) were treated within 1 month of symptom onset, while 27 (71.1%) were treated after 1 month of symptoms. The overall rate of cranial neuropathy improvement for all patients was 66.7%. The CN deficits resolved in 19 patients (42.2%), improved in 11 (24.4%), were unchanged in 14 (31.1%), and worsened in 1 (2.2%). Overtime, the rate of cranial neuropathy improvement was 33.3% (15/45), 68.8% (22/32), and 81.0% (17/21) at less than 6, 6, and 12 months, respectively. At last follow-up, 60% of patients in the isolated CN II group had improvement, while in the CN III, IV, or VI group, 85.7% had improved. Moreover, 100% (11/11) of patients experienced improvement if they were treated within 1 month of symptom onset, whereas 44.4% (12/27) experienced improvement if they treated after 1 month of symptom onset; 70.4% (19/27) of those with partial deficits improved compared with 30% (3/10) of those with complete deficits.

CONCLUSIONS

Cranial neuropathy caused by cerebral aneurysm responds similarly when the aneurysm is treated with the PED compared with open surgery and coil embolization. Lower morbidity and higher occlusion rates obtained with the PED may suggest it as treatment of choice for some of these lesions. Time to treatment is an important consideration regardless of treatment modality.

Radiosurgery for Cerebral Arteriovenous Malformations in A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA)-Eligible Patients: A Multicenter Study

BACKGROUND AND PURPOSE

The benefit of intervention for patients with unruptured cerebral arteriovenous malformations (AVMs) was challenged by results demonstrating superior clinical outcomes with conservative management from A Randomized Trial of Unruptured Brain AVMs (ARUBA). The aim of this multicenter, retrospective cohort study is to analyze the outcomes of stereotactic radiosurgery for ARUBA-eligible patients.

METHODS

We combined AVM radiosurgery outcome data from 7 institutions participating in the International Gamma Knife Research Foundation. Patients with ≥12 months of follow-up were screened for ARUBA eligibility criteria. Favorable outcome was defined as AVM obliteration, no postradiosurgery hemorrhage, and no permanently symptomatic radiation-induced changes. Adverse neurological outcome was defined as any new or worsening neurological symptoms or death.

RESULTS

The ARUBA-eligible cohort comprised 509 patients (mean age, 40 years). The Spetzler-Martin grade was I to II in 46% and III to IV in 54%. The mean radiosurgical margin dose was 22 Gy and follow-up was 86 months. AVM obliteration was achieved in 75%. The postradiosurgery hemorrhage rate during the latency period was 0.9% per year. Symptomatic and permanent radiation-induced changes occurred in 11% and 3%, respectively. The rates of favorable outcome, adverse neurological outcome, permanent neurological morbidity, and mortality were 70%, 13%, 5%, and 4%, respectively.

CONCLUSIONS

Radiosurgery may provide durable clinical benefit in some ARUBA-eligible patients. On the basis of the natural history of untreated, unruptured AVMs in the medical arm of ARUBA, we estimate that a follow-up duration of 15 to 20 years is necessary to realize a potential benefit of radiosurgical intervention for conservative management in unruptured patients with AVM.

Color-coded digital subtraction angiography in the management of a rare case of middle cerebral artery pure arterial malformation. A technical and case report

The advent of flow dynamics and the recent availability of perfusion analysis software have provided new diagnostic tools and management possibilities for cerebrovascular patients. To this end, we provide an example of the use of color-coded angiography and its application in a rare case of a patient with a pure middle cerebral artery (MCA) malformation. A 42-year-old male chronic smoker was evaluated in the emergency room due to sudden onset of severe headache, nausea, vomiting and left-sided weakness. Head computed tomography revealed a right basal ganglia hemorrhage. Cerebral digital subtraction angiography (DSA) showed a right middle cerebral artery malformation consisting of convoluted and ectatic collateral vessels supplying the distal middle cerebral artery territory-M1 proximally occluded. An associated medial lenticulostriate artery aneurysm was found. Brain single-photon emission computed tomography with and without acetazolamide failed to show problems in vascular reserve that would indicate the need for flow augmentation. Twelve months after discharge, the patient recovered from the left-sided weakness and did not present any similar events. A follow-up DSA and perfusion study using color-coded perfusion analysis showed perforator aneurysm resolution and adequate, albeit delayed perfusion in the involved vascular territory. We propose a combined congenital and acquired mechanism involving M1 occlusion with secondary dysplastic changes in collateral supply to the distal MCA territory. Angiographic and cerebral perfusion work-up was used to exclude the need for flow augmentation. Nevertheless, the natural course of this lesion remains unclear and long-term follow-up is warranted.

Acute neuronal injury and blood genomic profiles in a nonhuman primate model for ischemic stroke

The goal of this study was to characterize acute neuronal injury in a novel nonhuman primate (NHP) ischemic stroke model by using multiple outcome measures. Silk sutures were inserted into the M1 segment of the middle cerebral artery of rhesus macaques to achieve permanent occlusion of the vessel. The sutures were introduced via the femoral artery by using endovascular microcatheterization techniques. Within hours after middle cerebral artery occlusion (MCAO), infarction was detectable by using diffusion-weighted MRI imaging. The infarcts expanded by 24 h after MCAO and then were detectable on T2-weighted images. The infarcts seen by MRI were consistent with neuronal injury demonstrated histologically. Neurobehavioral function after MCAO was determined by using 2 neurologic testing scales. Neurologic assessments indicated that impairment after ischemia was limited to motor function in the contralateral arm; other neurologic and behavioral parameters were largely unaffected. We also used microarrays to examine gene expression profiles in peripheral blood mononuclear cells after MCAO-induced ischemia. Several genes were altered in a time-dependent manner after MCAO, suggesting that this ischemia model may be suitable for identifying blood biomarkers associated with the presence and severity of ischemia. This NHP stroke model likely will facilitate the elucidation of mechanisms associated with acute neuronal injury after ischemia. In addition, the ability to identify candidate blood biomarkers in NHP after ischemia may prompt the development of new strategies for the diagnosis and treatment of ischemic stroke in humans.

Long-term Results of Enterprise Stent-Assisted Coiling of Cerebral Aneurysms

BACKGROUND:

The Enterprise Vascular Reconstruction Device and Delivery System (Cordis; the Enterprise stent) was approved for use in conjunction with coiling of wide-necked aneurysms in 2007. No published long-term aneurysm occlusion or complication data exist for the Enterprise system.

OBJECTIVE:

We compiled data on consecutive patients treated with Enterprise stent-assisted coiling of aneurysms from 9 high-volume neurointerventional centers.

METHODS:

A 9 center registry was created to evaluate large volume data on the delayed safety and efficacy of the Enterprise stent system. Pooled data were compiled for consecutive patients undergoing Enterprise stent-assisted coiling at each institution prior to May 2009.

RESULTS:

Two-hundred twenty-nine patients with 229 aneurysms, 32 of which were ruptured aneurysms, were included in the study. Mean clinical and angiographic follow-up was 619.6 ± 26.4 days and 655.7 ± 25.2 days, respectively. Mean aneurysm size was 9.2 ± 0.4 mm. Fifty-nine percent of patients demonstrated 100% coil obliteration and 81% had 90% or higher occlusion at last follow-up angiography. A total of 19 patients (8.3%) underwent retreatment of their aneurysms during the follow-up period. Angiographic in-stent stenosis was seen in 3.4% and thromboembolic events occurred in 4.4%. Overall, 90% of patients who underwent Enterprise-assisted coiling had a modified Rankin Scale score of 2 or less at last follow-up. A poor modified Rankin Scale score was strongly associated with rupture status (P &lt; .001).

CONCLUSION:

Although this study is limited by its retrospective nature, the Enterprise stent system appears to be an effective, safe, and durable treatment for intracranial aneurysms when used in conjunction with coiling.

Abstract 3120: Clinical Profile, In-hospital and Long-term Mortality Rates of Hispanic Puerto Ricans Hospitalized with Acute Stroke

Background: Stroke mortality varies considerably according to race/ethnicity and place of residence. However, limited information is available about contemporary in-hospital death rates and one-year mortality in Hispanics hospitalized with acute stroke. We sought to examine the clinical characteristics, in-hospital, and one-year mortality death rates of Puerto Rican Hispanic patients hospitalized with an acute stroke.

Design/Methods: Observational study using data from the Puerto Rico Stroke Registry. The study population consisted of patients hospitalized with an initial (first) acute stroke in 11 medical centers of Puerto Rico in 2007. In-hospital mortality was calculated as the percentage of patients hospitalized with an initial acute stroke who died during the index hospitalization, one-year all-cause mortality was determined through the review of death records in the Puerto Rico Department of Health Vital Statistics Records.

Results: Of the 1528 consecutive patients hospitalized with an acute stroke, 1299 (85%) had an ischemic stroke. The mean age was 70 (+/- 28) years, and 53% were women. Patients hospitalized with an acute stroke had a considerable prevalence of comorbidities: 86% had hypertension, 52% had diabetes, 26% had hyperlipidemia, and 9% were current smokers. The overall in-hospital mortality rate was 11% and the one-year all-cause mortality rate was 26%. In comparison with men, women were older (71 years vs. 68 years), more likely to be hypertensive (89% vs. 83%, p=0.001), had similar odds of dying during hospitalization (OR=1.1 [95%CI= 0.8-1.6]), and more likely to die one year after hospital discharge (OR=1.3 [95%CI= 1.1-1.5]).

Discussion: Our findings indicate a high in-hospital and one year mortality rates after an initial acute stroke in Hispanic Puerto Ricans. Given the high, short and long-term, death rates associated with acute stroke, monitoring the clinical characteristics, death rates and factors associated with an increased risk of dying remains warranted.

Delayed Thrombosis or Stenosis Following Enterprise-Assisted Stent-Coiling: Is It Safe? Midterm Results of the Interstate Collaboration of Enterprise Stent Coiling

BACKGROUND:

Stent-assisted coiling of intracranial aneurysms with self-expanding stents has widened the applicability of neuroendovascular therapies to those aneurysms previously considered “uncoilable” because of poor morphology. The Enterprise Vascular Reconstruction Device and Delivery System (Cordis) has demonstrated promising initial short-term results. However, the rates of delayed in-stent stenosis or thrombosis are not known.

OBJECTIVE:

To report midterm results of the Enterprise stent system.

METHODS:

A 10-center registry was created to provide a large volume of data on the safety and efficacy of the Enterprise stent system. Pooled data were compiled for consecutive patients undergoing Enterprise stent-assisted coiling at each institution. Available follow-up data were evaluated for the incidence of in-stent stenosis, thrombosis, and aneurysm occlusion.

RESULTS:

In total, 213 patients (176 females) with 219 aneurysms were treated with the Enterprise stent. One hundred ten patients had undergone delayed angiography (≥30 days from stent placement, mean follow-up 174.6 days). Forty percent of patients demonstrated total occlusion with 88% having ≥90% aneurysm occlusion. Six percent of patients had delayed (&gt;30 days) angiographic findings, of which 3% demonstrated significant (≥50%) in-stent stenosis or occlusion. Seven delayed thrombotic events occurred (3%), along with 2 additional immediate periprocedural events. All 7 delayed events were concomitant to cessation of double-antiplatelet therapy.

CONCLUSION:

Midterm occlusion rates are excellent, and stenosis and thrombosis rates are comparable to other available neurovascular stents. Interruption of antiplatelet therapy appears to be a factor in those developing delayed stenosis or thrombosis.

Defining the risk of retreatment for aneurysm recurrence or residual after initial treatment by endovascular coiling: a multicenter study

OBJECTIVE

Endovascular treatment of intracranial aneurysms is less invasive than surgical repair but poses a higher risk for aneurysm recurrence, which may necessitate retreatment, thus adding to the long-term risk. Cerebrovascular neurosurgeons from 8 institutions in the United States and Puerto Rico collaborated to assess the risk of retreatment for residual or recurrent aneurysms after the initial endovascular coiling.

METHODS

Data were prospectively recorded for 311 patients with coiled intracranial aneurysms who underwent 352 retreatment procedures after angiographic or clinical recurrence (hemorrhage after initial coiling). Results analyzed included procedural complications and procedure-related morbidity. Morbidity was classified as major (modified Rankin scale score > 3) or minor, and temporary (<30 days) or permanent (>30 days).

RESULTS

Retreatment mortality was 0.85% per procedure and 0.96% per patient. Treatment-related rates were 0.32% per patient (0.28% per procedure) for permanent or temporary major disability; 1.29% for permanent minor disability (1.14% per procedure); and 1.61% for temporary minor disability (1.42% per procedure). Total risk for death or permanent major disability was 1.28% per patient and 1.13% per procedure.

CONCLUSION

Retreatment poses a low risk for patients with recurrences of intracranial aneurysms after initial coiling; this risk is smaller than that posed by the initial endovascular therapy. The risk of disability associated with retreatment for aneurysm recurrence after coiling must be considered prospectively in the choice of treatment but with the recognition that its effects are low in the overall management risk.

Treatment of intracranial aneurysms with the Enterprise stent: a multicenter registry

OBJECT

The development of self-expanding stents dedicated to intracranial use has significantly widened the applicability of endovascular therapy to many intracranial aneurysms that would otherwise have been untreatable by endovascular techniques. Recent Food and Drug Administration approval of the Enterprise Vascular Reconstruction Device and Delivery System (Cordis) has added a new option for self-expanding stent-assisted intracranial aneurysm coiling.

METHODS

The authors established a collaborative registry across multiple institutions to rapidly provide largevolume results regarding initial experience in using the Enterprise in real-world practice. Ten institutions (University at Buffalo, Thomas Jefferson University, University of Florida, Cleveland Clinic, Northwestern University, West Virginia University, University of Puerto Rico, Albany Medical Center Hospital, the Neurological Institute of Savannah, and the Barrow Neurological Institute) have provided consecutive data regarding their initial experience with the Enterprise.

RESULTS

In total, 141 patients (119 women) with 142 aneurysms underwent 143 attempted stent deployments. The use of Enterprise assistance with aneurysm coiling was associated with a 76% rate of > or = 90% occlusion. An inability to navigate or deploy the stent was experienced in 3% of cases, as well as a 2% occurrence of inaccurate deployment. Procedural data demonstrated a 6% temporary morbidity, 2.8% permanent morbidity, and 2% mortality (0.8% unruptured, 12% ruptured).

CONCLUSIONS

The authors report initial results of the largest series to date in using the Enterprise for intracranial aneurysm treatment. The Enterprise is associated with a high rate of successful navigation and low occurrence of inaccurate stent deployment. The overall morbidity and mortality rates were low; however, caution should be exercised when considering Enterprise deployment in patients with subarachnoid hemorrhage as the authors' experience demonstrated a high rate of associated hemorrhagic complications leading to death.