Posterior fossa AVMs: Increased risk of bleeding and worse outcome compared to supratentorial AVMs

The incidence of infratentorial arteriovenous malformation-associated aneurysms: an institutional case series and systematic literature review

BACKGROUND

Arteriovenous malformation (AVM)-associated aneurysms represent a high-risk feature predisposing them to rupture. Infratentorial AVMs have been shown to have a greater incidence of associated aneurysms, however the existing data is outdated and biased. The aim of our research was to compare the incidence of supratentorial vs infratentorial AVM-associated aneurysms.

METHODS

Patients were identified from our institutional AVM registry, which includes all patients with an intracranial AVM diagnosis since 2000, regardless of treatment. Records were reviewed for clinical details, AVM characteristics, nidus location (supratentorial or infratentorial), and presence of associated aneurysms. Statistical comparisons were made using Fisher's exact or Wilcoxon rank sum tests as appropriate. Multivariable logistic regression analysis determined independent predictors of AVM-associated aneurysms. As a secondary analysis, a systematic literature review was performed, where studies documenting the incidence of AVM-associated aneurysms stratified by location were of interest.

RESULTS

From 2000-2024, 706 patients with 720 AVMs were identified, of which 152 (21.1%) were infratentorial. Intracranial hemorrhage was the most common AVM presentation (42.1%). The incidence of associated aneurysms was greater in infratentorial AVMs compared with supratentorial cases (45.4% vs 20.1%; P<0.0001). Multivariable logistic regression demonstrated that infratentorial nidus location was the singular predictor of an associated aneurysm, odds ratio: 2.9 (P<0.0001). Systematic literature review identified eight studies satisfying inclusion criteria. Aggregate analysis indicated infratentorial AVMs were more likely to harbor an associated aneurysm (OR 1.7) and present as ruptured (OR 3.9), P<0.0001.

CONCLUSIONS

In this modern consecutive patient series, infratentorial nidus location was a significant predictor of an associated aneurysm and hemorrhagic presentation.

Clinical outcomes of posterior fossa arteriovenous malformations: a single center experience

BACKGROUND

Posterior fossa arterio-venous malformations (pfAVMs) are challenging lesions due to the anatomical particularities of the posterior fossa, and the high incidence of hemorrhagic presentation. The two most important goals when treating AVMs are preserving neurological function and preventing rupture, or a second hemorrhage. The aim of this study was to analyze the clinical and imaging features of pfAVMs to identify the factors that influence the prognosis of these patients.

METHODS

We conducted a single-center retrospective observational study that included patients treated at our institution with pfAVMs between January 1997 and December 2021.

RESULTS

A total of 48 patients were included. A good modified Rankin score (mRS) was observed in 33 cases (69%) at presentation. Thirty-four patients (71%) presented with a ruptured AVM. Out of these, 19 patients (40%) had intraventricular hemorrhage. Microsurgical resection was performed in 33 cases (69%), while in the other cases, the patients opted for conservative management (7 cases, 15%), stereotactic radiosurgery (SRS) (6 cases, 12%), or endovascular treatment (2 cases, 4%). Patients ≤ 30 years old were more prone to hemorrhagic presentation (OR: 5.23; 95% CI: 1.42-17.19; p = 0.024) and this remained an independent risk factor for rupture after multivariate analysis as well (OR: 4.81; 95% CI: 1.07-21.53; p = 0.040). Following multivariate analysis, the only factor independently associated with poor prognosis in the surgically treated subgroup was a poor clinical status (mRS 3-5) at admission (OR: 96.14; 95% CI: 5.15-1793.9; p = 0.002).

CONCLUSIONS

Management of posterior fossa AVMs is challenging, and patients who present with ruptured AVMs often have a poor clinical status at admission leading to a poor prognosis. Therefore, proper and timely management of these patients is essential.

Embolization of Ruptured Infratentorial Pial AVM in Pregnancy

A primigravida 22-year-old woman, at a gestation of 23 weeks, experienced bleeding from a pial arteriovenous malformation (AVM) located in the right cerebellum. After interdisciplinary consensus and with the informed consent of the patient and her family, AVM embolization was performed. Complete occlusion of the AVM was achieved by embolization with PHIL (precipitating hydrophobic injectable liquid). The calculated dose in the uterus was less than 1 µSv, which represents a negligible risk of harmful effects on the fetus. She delivered a baby at 37 weeks of gestation by cesarean section without complications. No congenital disorders were diagnosed by standard screening methods until the age of the newborn was two years. The angiography protocol must be optimized to minimize the radiation dose. Adequate shielding protection of the uterus is important. Premature termination of pregnancy is not necessary. Multidisciplinary care of neurologists, neurosurgeons, interventional radiologists, anesthesiologists, neonatologists, and obstetricians is necessary.

Long-term follow-up in patients with brain arteriovenous malformation based on the Quality of Life Scale and socioeconomic status

OBJECTIVE

Intracranial haemorrhage (ICH) is associated with permanent neurological disability resulting in deterioration of the quality of life (QoL). Our study assesses QoL in patients with ruptured arteriovenous malformation (AVM) in long-term follow-up at least five years after ICH and compares their QoL with the QoL of patient with non-ruptured AVM.

METHODS

Using the Quality of Life Scale (QOLS), the Patient Health Questionnaire (PHQ-9) for depressive symptoms, and the socioeconomic status (SES), a prospective assessment was performed. The modified Rankin Scale (mRS) was assessed for outcome.

RESULTS

Of 73 patients, 42 (57.5%) had ruptured (group 1) and 31 (42.5%) a non-ruptured AVM (group 2). Mean follow-up time was 8.6 ± 3.9 years (8.5 ± 4.2 years in group 1 and 8.9 ± 3.7 years in group 2). Favourable outcome (mRS 0-1) was assessed in 60 (83.3%) and unfavourable in 12 (16.7%) patients. Thirty-one of 42 patients (73.8%) in group 1 and 29 of 30 patients in group 2 (96.7%) had favourable outcomes. Mean QOLS was 85.6 ± 14.1 (group 1 86.1 ± 15.9, group 2 84.9 ± 11.4). Patients in group 1 did not show a significant difference in QoL compared to patients in group 2 (p = 0.23). Additional analyses in group 2 (rho =  - 0.73; p < 0.01) and in untreated AVM patients (rho =  - 0.81; p < 0.01) showed a strong correlation between QOLS and PHQ-9.

CONCLUSION

Long-term follow-up showed no difference in the QoL between patients with and without ICH caused by brain AVM. Outcome- and QoL-scores were high in both groups. Further studies are necessary to evaluate depression and anxiety symptoms in patients with AVM.

Longitudinal Changes in Size of Conservatively Managed Flow-Related Aneurysms Associated with Brain Arteriovenous Malformations

BACKGROUND

Flow aneurysms (FAs) associated with brain arteriovenous malformations (AVMs) are thought to arise from increased hemodynamic stress due to high-flow shunting. This study aims to describe the changes in conservatively managed FAs after successful AVM treatment.

METHODS

Patients with symptomatic AVMs and associated FAs who underwent successful treatment of the AVM between 2008 and 2017 were included. FA dimensions were measured on surveillance angiography to assess longitudinal changes.

RESULTS

Thirty-two patients were identified with 48 FAs. Sixteen (33%) FAs were treated endovascularly; 18 (38%) FAs were treated surgically; and 14 (29%) FAs (11 patients) were monitored. FAs demonstrated a decrease in size from 5.0 mm to 3.8 mm (24%; P = 0.016) and 4.9 mm to 3.6 mm (27%; P = 0.013) in height and width, respectively, over a median 35 months. However, on subgroup analysis, only class IIb aneurysms demonstrated a significant decrease in size (51% reduction in largest diameter, P = 0.046) and only 3 FAs (21%) resolved. There were no hemorrhages observed during follow-up.

CONCLUSIONS

While conservatively managed FAs demonstrated a reduction in size after the culprit AVM was treated, this was only significant in FAs located close to an AVM nidus (class IIb). There were no hemorrhages during the median 35 months' follow-up; however, long-term data are lacking. Our data support close observation of all conservatively managed aneurysms and a tailored approach based on the proximity to the nidus and observed changes in size.

Factors affecting the performance of brain arteriovenous malformation rupture prediction models

Background

In many cases, both the rupture rate of cerebral arteriovenous malformation (bAVM) in patients and the risk of endovascular or surgical treatment (when radiosurgery is not appropriate) are not low, it is important to assess the risk of rupture more cautiously before treatment. Based on the current high-risk predictors and clinical data, different sample sizes, sampling times and algorithms were used to build prediction models for the risk of hemorrhage in bAVM, and the accuracy and stability of the models were investigated. Our purpose was to remind researchers that there may be some pitfalls in developing similar prediction models.

Methods

The clinical data of 353 patients with bAVMs were collected. During the creation of prediction models for bAVM rupture, we changed the ratio of the training dataset to the test dataset, increased the number of sampling times, and built models for predicting bAVM rupture by the logistic regression (LR) algorithm and random forest (RF) algorithm. The area under the curve (AUC) was used to evaluate the predictive performances of those models.

Results

The performances of the prediction models built by both algorithms were not ideal (AUCs: 0.7 or less). The AUCs from the models built by the LR algorithm with different sample sizes were better than those built by the RF algorithm (0.70 vs 0.68, p < 0.001). The standard deviations (SDs) of the AUCs from both prediction models with different sample sizes displayed wide ranges (max range > 0.1).

Conclusions

Based on the current risk predictors, it may be difficult to build a stable and accurate prediction model for the hemorrhagic risk of bAVMs. Compared with sample size and algorithms, meaningful predictors are more important in establishing an accurate and stable prediction model.

Transcondylar fossa approach for the large, high-flow, and diffuse arteriovenous malformation of the posterior fossa

Posterior fossa high-grade arteriovenous malformations (AVMs) are challenging diseases. This video presents the treatment of a patient with a diffuse, high-flow AVM of the posterior fossa on the tonsil and cerebellopontine angle (4 cm in diameter) and deep draining veins. The patient had an intraventricular and cerebellar hemorrhage. After conservative treatment, total resection of the AVM was performed with embolization and surgery. The authors resected the nidus after the endovascular embolization, on the same day. The postoperative course was uneventful, and the patient was discharged with almost full recovery. The video can be found here: https://youtu.be/logCCn3uKUc.

Presence of direct vertebrobasilar perforator feeders in posterior fossa arteriovenous malformations and association with poor outcomes after endovascular treatment

OBJECTIVE

Treatment of posterior fossa arteriovenous malformations (PFAVMs) remains controversial as it is always challenging and may lead to major complications. Nonetheless, these lesions are more likely to bleed and generate poorer outcomes than other brain AVMs. The aim of this study was to evaluate the effect of endovascular treatment on long-term outcomes and identify the patient subgroups that might benefit from endovascular treatment.

METHODS

The authors performed a retrospective analysis of all consecutive cases of PFAVM managed at the Fondation Rothschild Hospital between 1995 and 2018. Clinical, imaging, and treatment data were prospectively gathered; these data were analyzed with respect to long-term outcomes.

RESULTS

Among the 1311 patients with brain AVMs, 114 (8.7%) had a PFAVM, and 88 (77.2%) of these patients had a history of bleeding. Of the 114 PFAVMs, 101 (88.6%) were treated (83 ruptured and 18 unruptured). The mean duration of follow-up was 47.6 months (range 0-240 months). Good neurological outcome at last follow-up was achieved in 79 cases (78.2%). Follow-up angiography showed obliteration of the PFAVM in 68.3% of treated cases. The presence of direct vertebrobasilar perforator feeders was associated with neurological deterioration (OR 5.63, 95% CI 11.15-30.76) and a lower obliteration rate (OR 15.69, 95% CI 2.52-304.03) after endovascular treatment. Other predictors of neurological deterioration and obliteration rate were consistent with the Spetzler-Martin grading system.

CONCLUSIONS

Advances in endovascular techniques have enabled higher obliteration rates in the treatment of PFAVMs, but complication rates are still high. Subgroups of patients who might benefit from treatment must be carefully selected and the presence of direct vertebrobasilar perforator feeders must call into question the indication for endovascular treatment.

Single-session Curative Embolization of Unruptured Cerebellar Arteriovenous Malformation with Precipitating Hydrophobic Injectable Liquid

Microsurgery is the treatment of choice for cerebellar arteriovenous malformations (AVMs). Nevertheless, endovascular therapy aims to be an effective treatment since the introduction of new embolic agents. Cerebellar AVMs represent a subgroup of vascular lesions with a high rate of hemorrhagic presentation compared with their cerebral counterpart. Moreover, they have a higher incidence of flow-related aneurysms when diagnosed. With this in mind, prompt treatment must be performed to avoid rebleeding with devastating consequences. Herein, we present the case of an unruptured cerebellar AVM treated with precipitating hydrophobic injectable liquid (PHIL) with complete obliteration.

Clinical impact of intraoperative hyperlactatemia during craniotomy

OBJECT

Patients often develop markedly elevated serum lactate levels during craniotomy although the reason for this is not entirely understood. Elevated lactate levels have been associated with poor outcomes in critically ill septic shock patients, as well as patients undergoing abdominal and cardiac surgeries. We investigated whether elevated lactate in craniotomy patients is associated with neurologic complications (new neurological deficits) as well as systemic complications.

METHODS

We performed a cohort study of elective craniotomy patients. Demographic and intraoperative data were collected, as well as three timed intraoperative arterial lactate values. Additional lactate, creatinine and troponin values were collected immediately postoperatively as well as 12 and 24 hours postoperatively. Assessment for neurologic deficit was performed at 6 hours and 2 weeks postoperatively. Hospital length-of-stay and 30-day mortality were collected.

RESULTS

Interim analysis of 81 patients showed that no patient had postoperative myocardial infarction, renal failure, or mortality within 30 days of surgery. There was no difference in the incidence of new neurologic deficit in patients with or without elevated lactate (10/26, 38.5% vs. 15/55 27.3%, p = 0.31). Median length of stay was significantly longer in patients with elevated lactate (6.5 vs. 3 days, p = 0.003). Study enrollment was terminated early due to futility (futility index 0.16).

CONCLUSION

Elevated intraoperative serum lactate was not associated with new postoperative neurologic deficits, other end organ events, or 30 day mortality. Serum lactate was related to longer hospital stay.

R2eD AVM Score

Background and Purpose- The management of unruptured brain arteriovenous malformations remains unclear. Using a large cohort to determine risk factors predictive of hemorrhagic presentation of arteriovenous malformations, this study aims to develop a predictive tool that could guide hemorrhage risk stratification. Methods- A database of 789 arteriovenous malformation patients presenting to our institution between 1990 and 2017 was used. A hold-out method of model validation was used, whereby the data was randomly split in half into training and validation data sets. Factors significant at the univariable level in the training data set were used to construct a model based on multivariable logistic regression. Model performance was assessed using receiver operating curves on the training, validation, and complete data sets. The predictors and the complete data set were then used to derive a risk prediction formula and a practical scoring system, where every risk factor was worth 1 point except race, which was worth 2 points (total score varies from 0 to 6). The factors are summarized by R₂eD arteriovenous malformation (acronym: R₂eD AVM). Results- In 755 patients with complete data, 272 (36%) presented with hemorrhage. From the training data set, a model was derived containing the following risk factors: nonwhite race (odds ratio [OR]=1.8; P=0.02), small nidus size (OR=1.47; P=0.14), deep location (OR=2.3; P<0.01), single arterial feeder (OR=2.24; P<0.01), and exclusive deep venous drainage (OR=2.07; P=0.02). Area under the curve from receiver operating curve analysis was 0.702, 0.698, and 0.685 for the training, validation, and complete data sets, respectively. In the entire study population, the predicted probability of hemorrhagic presentation increased in a stepwise manner from 16% for patients with no risk factors (score of 0) to 78% for patients having all the risk factors (score of 6). Conclusions- The final model derived from this study can be used as a predictive tool that supplements clinical judgment and aids in patient counseling.

Differences in bleeding patterns and outcome after intracerebral hemorrhage due to vascular malformations

BACKGROUND

Atypical intracerebral hemorrhage is a common form of primary manifestation of vascular malformations.

OBJECTIVE

The aim of the present study is to determine clues to the cause of bleeding according to hemorrhage pattern (lobar, basal ganglia, infratentorial).

METHODS

We retrospectively evaluated 343 consecutive neurosurgical patients with intracerebral hemorrhage (ICH), who were admitted to our neurosurgical department between 2006 and 2016. The study cohort includes only neurosurgical patients. Patients who underwent treatment by neurologists are not represented in this study. We assessed location of hemorrhage, hematoma volumes to rule out differences and predicitve variables for final outcome.

RESULTS

In 171 cases (49.9%) vascular malformations, such as arteriovenous malformations (AVMs), cavernomas, dural fistulas and aneurysms were the cause of bleeding. 172 (50.1%) patients suffered from an intracerebral hemorrhage due to amyloid angiopathy or long standing hypertension. In patients with infratentorial hemorrhage a malformation was more frequently detected as in patients with supratentorial hemorrhage (36% vs. 16%, OR 2.9 [1.8;4.9], p<0.001). Among the malformations AVMs were most common (81%). Hematoma expansion was smaller in vascular malformation than non-malformation caused bleeding (24.1 cm3 vs. 64.8 cm3, OR 0.5 [0.4;0.7], p < 0.001,). In 6 (2.1%) cases diagnosis remained unclear. Final outcome was more favorable in patients with vascular malformations (63% vs. 12%, OR 12.8 [4.5;36.2], p<0.001).

CONCLUSION

Localization and bleeding patterns are predictive factors for origin of the hemorrhage. These predictive factors should quickly lead to appropriate vascular diagnostic measures. However, due to the inclusion criteria the validity of the study is limited and multicentre studies with further testing in general ICH patients are required.

The Extent of Neurologic Improvement and Social Life in Young Patients with Ruptured and Unruptured Brain AVM: A Long-Term Follow-Up

BACKGROUND

Intracerebral hemorrhage, seizures, neurologic deficits, and cognitive impairments due to brain AVM in childhood are incriminating for brain and executive function with sequelae for further social life. Long-term follow-up data on brain AVM in young patients are rare, making it difficult to compare and evaluate treatment risks and outcomes.

METHODS

We studied young patients with brain AVM who were referred to our institution between 2005 and 2012 and for whom follow-up data were available. We stratified the patients into those with ruptured AVM (rAVM) and unruptured AVM (uAVM) and compared treated and nontreated patients. Differences in outcome and social participation were assessed.

RESULTS

A total of 29 young patients with brain AVM, median age 16 years, were included in our study with complete follow-up data of over 5 years (mean, 6 years). In 18 (62.1%) patients rAVM and in 11 (37.9%) patients uAVM were found. Twenty (69%) patients received treatment (rAVM 70% vs. uAVM 30%). Among treatment methods, microsurgery was most frequently used (rAVM 33.3% vs. uAVM 36.4%). In rAVM, 16 of 18 (88.9%) patients returned to work or school, and in uAVM, 11 (100%) patients did so. Concerning cognitive problems, no statistically significant difference was found in the 2 groups comparing treated and nontreated patients (P > 0.05). A favorable outcome was achieved in 13 (72.2%) patients with rAVM and in 11 (100%) patients with uAVM.

CONCLUSION

Favorable outcome was achieved in the majority of patients. The rate of neurologic improvement and participation in social life was very high in the 2 groups.