Should asymptomatic patients with hereditary haemorrhagic telangiectasia (HHT) be screened for cerebral vascular malformations? Data from 22,061 years of HHT patient life.

BACKGROUND The frequency of haemorrhage in individuals with hereditary haemorrhagic telangiectasia (HHT), 10% of whom will have cerebral arteriovenous (AV) malformations, could be high enough to justify screening. This would allow presymptomatic treatment to prevent early onset stroke in a condition that affects at least 1 in 8000 individuals. This is an important issue in view of the contrast between transatlantic management approaches, the worldwide dissemination of patient information, and the ethical implications of the diagnosis for the untreated patient. OBJECTIVES To define the annual incidence of haemorrhagic stroke in individuals with HHT. METHODS Retrospective study on stroke incidence in individuals with HHT and their immediate families (n = 674; 22,061 HHT patient years), specifically analysing patients under 46 years of age (17,515 patient years). The results were compared with stroke risk in the general population. RESULTS In the majority of cases, the haemorrhage was the first significant neurological event. Overcorrecting for any bias towards overestimation that would be introduced in excluding non-penetrant family members, cerebral haemorrhages were more than 20 times more common in male HHT subjects under the age of 45 years than in the general population (standardised ratio 22.99; 95% confidence interval, 13.14 to 37.33). Haemorrhages were also six times more common in female HHT subjects (6.18; 2.27 to 13.45). The incidence ratio of cerebral haemorrhage in male patients (1.84; 1.05 to 2.99) yielded a haemorrhage rate in individuals with cerebral AV malformations of 1.4-2.0% per annum, comparable to figures in the non-HHT cerebral AV malformation population. CONCLUSIONS These data contradict accepted wisdom in many countries that asymptomatic HHT patients are at a low (and acceptable) risk of haemorrhage. The data justify a more aggressive screening approach to identify small causative lesions amenable to treatment.