Experience of the Irish National Centre for Hereditary Haemorrhagic Telangiectasia 2003-2008

Hereditary haemorrhagic telangiectasia (HHT) is a group of autosomal dominant disorders of vascular structure. The Irish National Centre for HHT at the Mercy University Hospital, Cork, Ireland was founded in 2003. From 2003 to 2008, screening of 164 patients with contrast echocardiography, thoracic computerised tomography (CT) and cerebral magnetic resonance imaging (MRI) has identified 88 patients with definite HHT, 72 (82%) of whom had epistaxis, 70 (80%) had telangiectasia and 81 (92%) had a first-degree relative with HHT. We sought to describe the manifestations of HHT in an Irish population and to determine differences between internationally reported data. The HHT patient database was analysed to describe demographics, clinical manifestations and interventional procedures performed in all referred patients. Contrast echocardiography and/or CT were performed in 86 patients with definite HHT, identifying 27 patients (31%) with pulmonary arteriovenous malformations (pAVMs). Nineteen patients with single or multiple pAVMs had 28 embolisation procedures performed, with 1-6 pAVMs embolised per procedure. Cerebral MRI was performed in 78 (89%) patients and 2 (2.3%) had cerebral arteriovenous malformations (cAVMs). HHT prevalence is thought to be 1 in 2500-8000, suggesting that there are many undiagnosed cases in Irish patients. Internationally published data suggest a prevalence of 15-35% for pAVMs and 10-23% for cAVMs in patients with HHT. While the prevalence of pAVMs in our group is consistent with these data, the prevalence of cAVMs is considerably lower, suggesting that Irish patients with HHT may differ genotypically and phenotypically from those in other countries.