Risk of First Hemorrhage of Brain Arteriovenous Malformations During Pregnancy: A Systematic Review of the Literature.

BACKGROUND: Recommendations on the management of brain arteriovenous malformations (bAVM) with respect to pregnancy are based upon conflicting literature. OBJECTIVE: To systematically review the reported risk and annualized rate of first intracranial hemorrhage (ICH) from bAVM during pregnancy and puerperium. METHODS: MEDLINE, EMBASE, and Scopus databases were searched for relevant articles in English published before April 2018. Studies providing a quantitative risk of ICH in bAVM during pregnancy were eligible. RESULTS: From 7 initially eligible studies, 3 studies met the criteria for providing quantitative risk of first ICH bAVM during pregnancy. Data from 47 bAVM ICH during pregnancy across 4 cohorts were extracted for analysis. Due to differences in methodology and definitions of exposure period, it was not appropriate to combine the cases. The annualized risk of first ICH during pregnancy for these 4 cohorts was 3.0% (95% confidence interval [CI]: 1.7-5.2%); 3.5% (95% CI: 2.4-4.5%); 8.6% (95% CI: 1.8-25%); and 30% (95% CI: 18-49%). Only the last result from the last cohort could be considered significantly increased in comparison with the nonpregnant period (relative rate 6.8, 95% CI: 3.6-13). The limited number of eligible studies and variability in results highlighted the need for enhanced rigor of future research. CONCLUSION: There is no conclusive evidence of an increased risk of first hemorrhage during pregnancy from bAVM. Because advice to women with bAVM may influence the management of pregnancy or bAVM with significant consequences, we believe that a retrospective multicenter, case crossover study is urgently required.

Laminar Wall Shear Stress in Brain Arteriovenous Malformations: Systematic Review of Literature.

BACKGROUND: Laminar wall sheer stress (LWSS) modulates inflammatory activity of the endothelium and may be a contributing factor in many cerebrovascular pathologies. There is a lack of consensus whether significant differences in LWSS exist between feeding vessels in brain arteriovenous malformation (bAVM) and healthy vessels. A systematic review of LWSS research in bAVM was undertaken, including the methods used and the assumptions made in determining LWSS. METHODS: Ovid MEDLINE, EMBASE, and Scopus electronic databases were systematically searched from inception for articles calculating LWSS in bAVM cases. LWSS values were extracted for comparison between ipsilateral bAVM feeding arteries and healthy contralateral vessels or healthy normative data. RESULTS: Three retrospective cohort studies were identified, reporting on 42 adult and pediatric bAVM cases. Mean LWSS (mLWSS) in healthy vessels (contralateral vessels or normative controls) typically ranged from 1.2-2.7 Pa, while mLWSS values in untreated bAVM feeding arteries typically ranged from 1.6-3.6 Pa. All studies had mixed cohorts of ruptured and unruptured cases, obscuring the relationship between LWSS and bAVM history. CONCLUSIONS: mLWSS values in healthy arteries and bAVM feeding vessels tend to be low and overlapping. Further research of high scientific and methodologic quality is necessary to improve understanding of how LWSS hemodynamics relate to bAVM formation, rupture, and treatment.

De novo brain arteriovenous malformation after tumor resection: case report and literature review.

The congenital origin of brain arteriovenous malformations (bAVMs) has been increasingly challenged by reports of de novo bAVMs in patients previously confirmed to have no vascular malformation. We describe the oldest patient reported in the English language literature harboring a de novo bAVM. An uneventful frontal convexity meningioma resection was performed for a 60-year-old woman, and at 67 years of age, a bAVM was detected by MRI and confirmed by digital subtraction angiography at the site of the previous meningioma resection. This case adds to the growing literature that the etiology of bAVMs is most likely multifactorial.

Critical review of brain AVM surgery, surgical results and natural history in 2017.

BACKGROUND: An understanding of the present standing of surgery, surgical results and the role in altering the future morbidity and mortality of untreated brain arteriovenous malformations (bAVMs) is appropriate considering the myriad alternative management pathways (including radiosurgery, embolization or some combination of treatments), varying risks and selection biases that have contributed to confusion regarding management. The purpose of this review is to clarify the link between the incidence of adverse outcomes that are reported from a management pathway of either surgery or no intervention with the projected risks of surgery or no intervention. METHODS: A critical review of the literature was performed on the outcomes of surgery and non-intervention for bAVM. An analysis of the biases and how these may have influenced the outcomes was included to attempt to identify reasonable estimates of risks. RESULTS: In the absence of treatment, the cumulative risk of future hemorrhage is approximately 16% and 29% at 10 and 20 years after diagnosis of bAVM without hemorrhage and 35% and 45% at 10 and 20 years when presenting with hemorrhage (annualized, this risk would be approximately 1.8% for unruptured bAVMs and 4.7% for 8 years for bAVMs presenting with hemorrhage followed by the unruptured bAVM rate). The cumulative outcome of these hemorrhages depends upon whether the patient remains untreated and is allowed to have a further hemorrhage or is treated at this time. Overall, approximately 42% will develop a new permanent neurological deficit or death from a hemorrhagic event. The presence of an associated proximal intracranial aneurysm (APIA) and restriction of venous outflow may increase the risk for subsequent hemorrhage. Other risks for increased risk of hemorrhage (age, pregnancy, female) were examined, and their purported association with hemorrhage is difficult to support. Both the Spetzler-Martin grading system (and its compaction into the Spetzler-Ponce tiers) and Lawton-Young supplementary grading system are excellent in predicting the risk of surgery. The 8-year risk of unfavorable outcome from surgery (complication leading to a permanent new neurological deficit with a modified Rankin Scale score of greater than one, residual bAVM or recurrence) is dependent on bAVM size, the presence of deep venous drainage (DVD) and location in critical brain (eloquent location). For patients with bAVMs who have neither a DVD nor eloquent location, the 8-year risk for an unfavorable outcome increases with size (increasing from 1 cm to 6 cm) from 1% to 9%. For patients with bAVM who have either a DVD or eloquent location (but not both), the 8-year risk for an unfavorable outcome increases with the size (increasing from 1 cm to 6 cm) from 4% to 35%. For patients with bAVM who have both a DVD and eloquent location, the 8-year risk for unfavorable outcome increases with size (increasing from 1 cm to 3 cm) from 12% to 38%. CONCLUSION: Patients with a Spetzler-Ponce A bAVM expecting a good quality of life for the next 8 years are likely to do better with surgery in expert centers than remaining untreated. Ongoing research is urgently required on the outcome of management pathways for bAVM.

Deliberate employment of postoperative hypotension for brain arteriovenous malformation surgery and the incidence of delayed postoperative hemorrhage: a prospective cohort study.

OBJECTIVE The aim of this study was to examine the impact of deliberate employment of postoperative hypotension on delayed postoperative hemorrhage (DPH) for all Spetzler-Ponce Class (SPC) C brain arteriovenous malformations (bAVMs) and SPC B bAVMs ≥ 3.5 cm in diameter (SPC B 3.5+). METHODS A protocol of deliberate employment of postoperative hypotension was introduced in June 1997 for all SPC C and SPC B 3.5+ bAVMs. The aim was to achieve a maximum mean arterial blood pressure (BP) ≤ 70 mm Hg (with cerebral perfusion pressure > 50 mm Hg) for a minimum of 7 days after resection of bAVMs (BP protocol). The authors compared patients who experienced DPH (defined as brain hemorrhage into the resection bed that resulted in a new neurological deficit or that resulted in reoperation during the hospitalization for microsurgical bAVM resection) between 2 periods (prior to adopting the BP protocol and after introduction of the BP protocol) and 4 bAVM categories (SPC A, SPC B 3.5- [that is, SPC B < 3.5 cm maximum diameter], SPC B 3.5+, and SPC C). Patients excluded from treatment by the BP protocol were managed in the intensive care unit to avoid moderate hypertensive episodes. The pooled cases of all bAVM treated by surgery were analyzed to identify characteristics associated with the risk of DPH. These identified characteristics were then examined by multiple logistic regression analysis in both SPC B 3.5+ and SPC C cases. RESULTS From a cohort of 641 bAVMs treated by microsurgery, 32 patients with DPH were identified. Of those, 66% (95% CI 48-80) had a permanent new neurological deficit with a modified Rankin Scale score of 2-6. This included a mortality rate of 13% (95% CI 4.4-29). The BP protocol was used to treat 162 patients with either SPC B 3.5+ or SPC C. For SPC B 3.5+, there was no significant reduction in DPH with the introduction of the BP protocol (p = 0.77). For SPC C, there was a significant (p = 0.035) reduction of DPH from 29% (95% CI 13%-53%) to 8.2% (95% CI 3.2%-18%) associated with the introduction of the BP protocol. Multiple logistic regression analysis found that the absence of the BP protocol (p = 0.011, odds ratio 7.5, 95% CI 1.6-36) remained significant for the development of DPH in patients with SPC C bAVMs. CONCLUSIONS Treating patients with SPC C bAVMs with a protocol that lowers BP immediately after resection seems to reduce the risk of DPH. For SPC A and SPC B 3.5- bAVMs, there is unlikely to be a need to do more than avoid postoperative hypertension. For SPC B 3.5+ bAVMs, a larger number of patients would be required to test the absence of benefit of the BP protocol.