Background

Children with untreated brain arteriovenous malformations (bAVM) are at risk of encountering life-threatening hemorrhage very early in their lives. The primary aim of invasive treatment is to reduce unfavorable outcome associated with a bAVM rupture. A better understanding of the morbidity of bAVM hemorrhage might be helpful for weighing the risks of untreated bAVM and invasive treatment. Our aim was to assess the clinical outcome after bAVM rupture and identify features to predict severe hemorrhage in children.

Methods

We identified all consecutive children admitted to our institution for bAVMs between July 2009 and December 2014. Clinical outcome after hemorrhagic presentation and subsequent hemorrhage was evaluated using the modified Rankin Scale (mRS) for children. The association of demographic characteristics and bAVM morphology with severe hemorrhage (mRS >3 or requiring emergency hematoma evacuation) was studied using univariate and multivariable regression analyses. A nomogram based on multivariable analysis was formulated to predict severe hemorrhage risk for individual patients.

Results

A total of 134 patients were identified with a mean treatment-free follow-up period of 2.1 years. bAVM ruptured in 83 (62%) children: 82 had a hemorrhage at presentation and 6 of them experienced a recurrent hemorrhage during follow-up; 1 patient had other diagnostic symptoms but bled during follow-up. Among them, 49% (41/83) had a severe hemorrhage; emergency hematoma evacuation was required in 28% of them (23/83), and 24% (20/83) remained as disabled (mRS ≥3) at last follow-up. Forty-six percent (38/82) of children with hemorrhagic presentation were severely disabled (mRS >3). Forty-three percent (3/7) were severely disabled after subsequent hemorrhage. The annual rate of severe subsequent hemorrhage was 1% in the overall cohort and 3.3% in children with ruptured presentation. All the subsequent severe hemorrhage events occurred in children with severe hemorrhage history (7%, 3/41). Periventricular location, non-temporal lobe location, and long draining vein were predictors for severe hemorrhage in pediatric untreated bAVMs. A nomogram based on bAVM morphology was contracted to predict severe hemorrhage risk for individual patients, which was well calibrated and had a good discriminative ability (adjusted C-statistic, 0.72).

Conclusions

Evaluating bAVM morbidity and morphology might be helpful for weighing the risks of untreated bAVM in pediatric patients.

OBJECTIVES:A precise assessment of angioarchitectural characteristics using noninvasive imaging is helpful for serial follow-up and weighting risk of natural history in unruptured brain arteriovenous malformation (bAVM). This study aimed to test the hypothesis that susceptibility weighted imaging (SWI) would provide an accurate evaluation of angioarchitectural features of unruptured bAVM. METHODS:A total of 81 consecutive patients with unruptured bAVM were examined. Image quality of SWI for the assessment of bAVM angioarchitectural features was determined by a 5-point scale. The accuracy of SWI for detection of angioarchitectural features was evaluated using digital subtraction angiography as a standard reference and further compared among unruptured bAVMs with or without silent intralesional microhemorrhage on SWI to examine the potential confounding effect of microhemorrhage on image analysis. RESULTS:All lesions were identified on SWI. Image quality of SWI was judged to be at least adequate for diagnosis (range, 3-5) in all patients by both readers. Using digital subtraction angiography as a reference standard, the area under the receiver operating curve of detection of deep or posterior fossa location, exclusively deep venous drainage, venous ectasia, venous varices, and the presence of associated aneurysm on SWI was 1, 0.93, 0.94, 0.95, and 0.83, respectively. Silent intralesional microhemorrhage were detected in 39 patients (48.15%) on SWI and no significant difference (P > 0.05) was found in angioarchitectural features between patients with and without silent microhemorrhage. CONCLUSIONS:SWI might be a noninvasive alternative technique for angiography in the angioarchitectural assessment of unruptured bAVM.