Bleeding risk of cerebrovascular malformations in hereditary hemorrhagic telangiectasia

Object. Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal-dom inant vascular dysplasia with a high prevalence of cerebrovascular malforma tions (CVMs), mostly manifested as arteriovenous malformations (AVMs). The natural history and bleeding risk of these CVMs is unknown. The authors inv estigated the risk of bleeding in conjunction with clinical and radiologica l features in patients with Hi-IT and proven CVMs. Methods. Intravenous digital subtraction (DS) angiography was used to scree n 196 patients with HHT for the presence of CVMs. Patients with abnormal re sults on DS angiography were asked to undergo a conventional cerebral angio graphic study. All patients with a proven CVM were assessed by a neurologis t. The bleeding risk was retrospectively and prospectively calculated for p atients with AVMs only, as well as for the whole cohort of patients with CV Ms. Twenty-four patients (12.2%; 16 female and eight male), aged 14 to 66 years (mean 35.4 years) with one or more CVMs were identified. Fifteen patients (62.5%) had a CVM and a pulmonary AVM. Eleven patients (45.8%) exhibited no neurological signs of their CVM; six (25%) had headache or migraine; four (16.7%) had seizures; and three (12.5%) had an intracranial hemorrhage. Twe nty-two patients had at least one AVM (with a total of 28 AVMs), whereas tw o patients only had telangiectases. Twenty-seven AVMs were small (96%), 36% were located in eloquent areas of the brain, and 82% had superficial venou s drainage. One third of the patients had multiple CVMs. The bleeding risk for patients with at least one AVM ranged from 0.41 to 0.72% per year, and for the whole cohort the range was 0.38 to 0.69% per year. Calculation of t he bleeding risk as determined by lesion-years ranged from 0.36 to 0.56% pe r year for patients with AVMs and from 0.27 to 0.46% per year for all patie nts with CVMs. Conclusions. Patients with HHT have a high risk of harboring a CVM, especia lly in the presence of a pulmonary AVM. These CVMs are mostly low-grade AVM s (Spetzler-Martin Grade I or II), are frequently multiple, and have a lowe r risk of bleeding than that associated with sporadic AVMs. Female patients are more often affected than male patients. The inherent low sensitivity o f DS angiography screening for CVMs may yield false negative results.