Ruptured Brain Arteriovenous Malformations: Surgical Timing and Outcomes-A Retrospective Study of 25 Cases

Optimal Timing of Microsurgical Treatment for Ruptured Arteriovenous Malformations: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

The timing of microsurgical treatment (MST) for ruptured brain arteriovenous malformations (bAVM) is a contentious issue in the literature. This study aimed to investigate the impact of MST timing on outcomes in patients with ruptured bAVMs, considering MST with and without preoperative endovascular treatment (EVT).

METHOD

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines, a comprehensive search was conducted across multiple databases, yielding 15 studies meeting the inclusion criteria. The timing was defined as the duration from the rupture of bAVM to the MST. The patients were divided into 4 different groups based on MST timing: <48 hours, <1 week, <2 weeks, and <1 month. The primary outcome was favorable outcome defined as a modified Rankin Scale score of 0 to 2 or a Glasgow Outcome Scale score of 4 to 5 in the last clinical follow-up. Secondary outcomes included periprocedural mortality and complete excision.

RESULTS

MST time >48 hours were associated with a significantly higher favorable outcome rate (odds ratio: 9.71, 95% Cl: 3.09-30.57, P < .01) and a lower mortality rate (OR: 0.15, 95% Cl: 0.02-0.88, P = .04) compared with MST timing ≤48 hours. After exclusion of patients who underwent MST with preoperative EVT, MST time >48 hours had a significantly higher rate of favorable outcome (OR: 9.39, 95% CI: 2.53-34.89, P < .01).

CONCLUSION

This meta-analysis suggests that delayed surgical intervention beyond 48 hours may be associated with improved favorable outcomes in patients who underwent MST with and without preoperative EVT for ruptured bAVMs.

Early versus Delayed Surgical Management of Ruptured Arteriovenous Brain Malformations in a Tertiary Referral Center in Colombia, South America

BACKGROUND

Surgical timing after rupture of brain arteriovenous malformations (AVMs) is controversial. There is scarce literature on AVM surgical outcomes from developing countries. This study aims to determine if there is a difference between early and delayed surgical resection for patients with ruptured brain AVMs.

METHODS

This single-center retrospective review included patients who underwent surgical resection for ruptured brain AVMs in Colombia. Patients were stratified by the timing of surgical intervention relative to the rupture into early (≤72 hours of bleeding) and delayed (>72 hours) resection. Continuous variables were analyzed using an independent t-test, and dichotomous variables were analyzed using a χ2 test. A linear regression analysis was performed with the final mRankin score at 2 years as the dependent variable; P < 0.05 was considered significant.

RESULTS

Thirty-one patients were identified. The early treatment group included 14 (45.2%) patients, and the delayed group included 17 (54.8%) patients. The mean (SD) length of time between AVM rupture and surgical resection was 1.6 ± 1.2 days and 12.4 ± 8.4 days, respectively (P < 0.001). There were no differences regarding demographics, perioperative variables, and postoperative outcomes between groups. In the linear regression analysis, the only variable that had a significant association with the final mRankin score was the initial Glasgow Coma Scale, which had a β coefficient of -0.6341 (95% confidence interval: -0.41,-0.017, P = 0.035).

CONCLUSIONS

In this case series of 31 patients from a developing country, there were no differences in clinical outcomes at the final follow-up between acute and delayed surgical interventions for ruptured AVMs. The most important factor associated with the final outcomes was the initial Glasgow Coma Scale.

Factors Associated with Unfavorable Clinical Presentations in Patients with Ruptured BrainArteriovenous Malformations

BACKGROUND

Rupture of brain arteriovenous malformations (bAVMs) carries potentially devastating consequences. For patients presenting with ruptured bAVMs, several clinical grading systems have been shown to predict long-term patient morbidity and may be taken into consideration when making clinical decisions. Unfortunately, use of these scoring systems is typically limited to their prognostic value and offer little to patients in therapeutic benefit. Tools are needed not only to predict prognosis for patients experiencing ruptured bAVMs but to gain insight into what characteristics predispose patients to poor long-term outcomes before they rupture. Our objective was to find clinical, morphologic, and demographic variables that correlate with unfavorable clinical grades on presentation in patients with ruptured bAVMs.

METHODS

We retrospectively reviewed a cohort of patients with ruptured bAVMs. Linear regression models were used to test whether Glasgow Coma Scale (GCS) and Hunt-Hess scores on presentation(outcomes) were associated with patient and arteriovenous malformation (AVM) characteristics (predictors) individually.

RESULTS

GCS and Hunt-Hess were assessed following bAVM rupture for 121 brain cases. The median age at rupture was 28.5 years, and 62 (51%) were female. Smoking history was associated with worse GCS; current and past smokers had GCS scores 1.33 points lower on average than nonsmokers (95% confidence interval [CI] -2.59 to -0.07, P = 0.039) and had worse Hunt-Hess scores (0.42, 95% CI 0.07-0.77, P = 0.019). Associated aneurysms were associated with worse GCS (-1.60, 95% CI -3.16 to -0.05, P = 0.043) and trended towards worse Hunt-Hess scores (0.42 points, 95% CI -0.01 to 0.86, P = 0.057).

CONCLUSIONS

Patient smoking status and presence of an AVM associated aneurysm were shown to have modest correlations with unfavorable clinical grades (Hunt-Hess, GCS) on presentation, with unfavorable clinical grades being associated with long-term patient prognosis following bAVM rupture. Further investigation using AVM-specific grading scales and external data are needed to determine the utility of these and other variables in clinical practice for patients with bAVM.

Delayed versus immediate intervention of ruptured brain arteriovenous malformations: A case report

BACKGROUND

Brain arteriovenous malformations (bAVMs) remains one of the most prevalent causes of intracranial hemorrhage and stroke-like syndromes in the young adult population. Although it has been agreed upon that definitive treatment using either single or multi-modal approach is warranted for successful bAVM management, much debate still revolves regarding the optimal timing of definitive treatment.

CASE SUMMARY

In this report, we present a case of delayed, definitive endovascular treatment for ruptured bAVM in a 21-year-old female, 3 mo post-ictus. The bAVM, with a left pericallosal feeding artery and cortical draining veins, was successfully obliterated through embolization using the Onyx 18. On follow-up the patient has recommenced her daily activities and experiences only mild occasional headaches with mild motor deficits. The report leads to our review on an important issue regarding the optimal timing of ruptured bAVM definitive management and bring forward the current evidence available on delayed vs immediate definitive bAVM intervention. We also highlight current issues that need to be addressed for clearer guidelines on definitive therapy initiation.

CONCLUSION

Current treatment paradigms of ruptured bAVM remains elusive, with substantial heterogeneity in the current literature. A consensus on the definition of “acute” vs “delayed”, management goal, follow-up length and outcome parameters are required to support formation of a clear paradigm.

Traffic Patterns of the Migrating Endothelium: How Force Transmission Regulates Vascular Malformation and Functional Shunting During Angiogenic Remodelling

Angiogenesis occurs in distinct phases: initial spouting is followed by remodelling in which endothelial cells (ECs) composing blood vessels rearrange by migrating against the direction of flow. Abnormal remodelling can result in vascular malformation. Such is the case in mutation of the Alk1 receptor within the mouse retina which disrupts flow-migration coupling, creating mixed populations of ECs polarised with/against flow which aggregate into arteriovenous malformations (AVMs). The lack of live imaging options in vivo means that the collective EC dynamics that drive AVM and the consequences of mixed populations of polarity remain a mystery. Therefore, our goal is to present a novel agent-based model to provide theoretical insight into EC force transmission and collective dynamics during angiogenic remodelling. Force transmission between neighbouring agents consists of extrusive forces which maintain spacing and cohesive forces which maintain the collective. We performed migration simulations within uniformly polarised populations (against flow) and mixed polarity (with/against flow). Within uniformly polarised populations, extrusive forces stabilised the plexus by facilitating EC intercalation which ensures that cells remained evenly distributed. Excess cohesion disrupts intercalation, resulting in aggregations of cells and functional shunting. Excess cohesion between ECs prevents them from resolving diameter balances within the plexus, leading to prolonged flow reversals which exert a critical behaviour change within the system as they switch the direction of cell migration and traffic patterns at bifurcations. Introducing mixtures of cell polarity dramatically changed the role of extrusive forces within the system. At low extrusion, opposing ECs were able to move past each other; however, at high extrusion the pushing between cells resulted in migration speeds close to zero, forming traffic jams and disrupting migration. In our study, we produced vascular malformations and functional shunting with either excess cohesion between ECs or mixtures of cell polarity. At the centre of both these mechanisms are cell-cell adherens junctions, which are involved in flow sensing/polarity and must remodelling dynamically to allow rearrangements of cells during vascular patterning. Thus, our findings implicate junctional dysfunction as a new target in the treatment and prevention of vascular disease and AVMs.