P.192 Arterial Hemodynamics and the Clinical Presentation of Cerebral Arteriovenous Malformations

Background: Arterial Hemodynamics have been implicated in hemorrhage from cerebral arteriovenous malformations (AVMs). The correlation between hemodynamic characteristics and the tendency of AVMs to rupture has been explored in the past, and various theories have been proposed to explain the clinical presentation of AVMs as a hemorrhage vs. seizure. Methods: We monitored feeder artery pressures in 45 patients with AVMS (16 presenting with hemorrhage, 29 without) during super selective angiography and AVM embolization. Results: Mean feeder artery pressure (FP) was found to be 49mm Hg. The mean FP in patients presenting with hemorrhage was somewhat higher than in those without hemorrhage, but the difference was not statistically significant (53.8 mm Hg vs 47.0 mm Hg, p=0.13). Systemic mean pressure was found to correlate with AVM size (r=-0.31, p=0.037). Significant predictors of feeder artery pressure were systemic pressure, AVM size, and the distance of microcatheter from the circle of Willis. Meanwhile, the presence or absence of venous outflow stenosis and the position of the AVM nidus (superficial or deep to the cortical surface) were the most significant predictors of AVM hemorrhage vs seizures. Conclusions: Anatomic factors may be more important than arterial hemodynamic factors in determining the clinical presentation of cerebral AVMs.

Spontaneous regression of a thrombosed cerebral arteriovenous malformation in a patient with a prothrombotic state associated with multiple myeloma: A case report and literature review

Background: Cerebral arteriovenous malformations (AVMs) are pathologic communications between veins and arteries of the brain vasculature. Its spontaneous regression is rare, and many factors have been described in the effort to explain this phenomenon, including a hypercoagulable state. Case Description: We present the case of a spontaneous unruptured AVM regression in a patient where thrombosis of the malformation was found, probably due to a prothrombotic state associated with multiple myeloma (MM). Conclusion: We aim to contribute to the study of this rare phenomenon, presenting the relationship between a hypercoagulable state caused by MM and the spontaneous AVM regression that has not been previously reported.

Controlled arterial hypotension during resection of cerebral arteriovenous malformations

Background Resection of cerebral arteriovenous malformations (AVM) is technically demanding because of size, eloquent location or diffuse nidus. Controlled arterial hypotension (CAH) could facilitate haemostasis. We performed a study to characterize the duration and degree of CAH and to investigate its association with blood loss and outcome. Methods We retrospectively analysed intraoperative arterial blood pressure of 56 patients that underwent AVM-resection performed by the same neurosurgeon between 2003 and 2012. Degree of CAH, AVM size, grading and neurological outcome were studied. Patients were divided into two groups, depending on whether CAH was performed (hypotension group) or not (control group). Results The hypotension group consisted of 28 patients, which presented with riskier to treat AVMs and a higher Spetzler-Martin grading. CAH was achieved by application of urapidil, increasing anaesthetic depth or a combination thereof. Systolic and mean arterial blood pressure were lowered to 82 ± 7 and 57 ± 7 mmHg, respectively, for a median duration of 58 min [25% percentile: 26 min.; 75% percentile: 107 min]. In the hypotension group, duration of surgery (4.4 ± 1.3 h) was significantly (p < 0.001) longer, and median blood loss (500 ml) was significantly (p = 0.002) higher than in the control group (3.3 ± 0.9 h and 200 ml, respectively). No case fatalities occurred. CAH was associated with a higher amount of postoperative neurological deficits. Conclusions Whether CAH caused neurological deficits or prevented worse outcomes could be clarified by a prospective randomised study, which is regarded as ethically problematic in the context of bleeding. CAH should only be used after strict indication and should be applied as mild and short as possible.

Factors associated with seizures at initial presentation in pediatric patients with cerebral arteriovenous malformations

OBJECTIVE Children with cerebral arteriovenous malformations (AVMs) can present with seizures, potentially increasing morbidity and impacting clinical management. However, the factors that lead to seizures as a presenting sign are not well defined. While AVM-related seizures have been described in case series, most studies have focused on adults and have included patients who developed seizures after an AVM rupture. To address this, the authors sought to analyze demographic and morphological characteristics of AVMs in a large cohort of children. METHODS The demographic, clinical, and AVM morphological characteristics of 189 pediatric patients from a single-center database were studied. Univariate and multivariate logistic regression models were used to test the effect of these characteristics on seizures as an initial presenting symptom in patients with unruptured brain AVMs. RESULTS Overall, 28 of 189 patients initially presented with seizures (14.8%). By univariate comparison, frontal lobe location (p = 0.02), larger AVM size (p = 0.003), older patient age (p = 0.04), and the Supplemented Spetzler-Martin (Supp-SM) grade (0.0006) were associated with seizure presentation. Multivariate analysis confirmed an independent effect of frontal lobe AVM location and higher Supp-SM grade. All patients presenting with seizures had AVMs in the cortex or subcortical white matter. CONCLUSIONS While children and adults share some risk factors for seizure presentation, their risk factor profiles do not entirely overlap. Pediatric patients with cortical AVMs in the frontal lobe were more likely to present with seizures. Additionally, the Supp-SM grade was highly associated with seizure presentation. Future clinical research should focus on the effect of therapeutic interventions targeting AVMs on seizure control in these patients.

Axis fracture due to giant cranial AVM

ABSTRACT Cerebral arteriovenous malformations (AVMs) are a vascular anomaly consisting of a bundle of direct connection of arteries and veins. AVMs clinical expression ranges from complete asymptomatic, and thus incidentally found, to life threatening with rupturing and bleeding. In this wide spectrum, osteolysis is considered as a rare complication of interosseous AVMs, and only few cases of mandible and maxilla osteolysis have been reported. We present, herein, a case of an intracranial AVM, which has caused in the course of the time an osteolysis of the dens and axis.