Background: Mutations in the genes ENG, ACVRL1 and SMAD4 that are part of the transforming growth factor-beta signalling pathway cause hereditary haemorrhagic telangiectasia (HHT). Mutations in non-HHT genes within this same pathway have been found to associate with aortic dilation. Therefore, we investigated the presence of aortic dilation in a large cohort of HHT patients as compared to non-HHT controls.
Methods: Chest computed tomography of consecutive HHT patients (ENG, ACVRL1 and SMAD4 mutation carriers) and non-HHT controls were reviewed. Aortic root dilation was defined as a z-score>1.96. Ascending and descending aorta dimensions were corrected for age, gender and body surface area.
Results: In total 178 subjects (57.3% female, mean age 43.9±14.9years) were included (32 SMAD4, 47 ENG, 50 ACVRL1 mutation carriers and 49 non-HHT controls). Aortopathy was present in a total of 42 subjects (24% of total). Aortic root dilatation was found in 31% of SMAD4, 2% of ENG, 6% of ACVRL1 mutation carriers, and 4% in non-HHT controls (p<0.001). The aortic root diameter was 36.3±5.2mm in SMAD4 versus 32.7±3.9mm in the non-SMAD4 group (p=0.001). SMAD4 was an independent predictor for increased aortic root (β-coefficient 3.5, p<0.001) and ascending aorta diameter (β-coefficient 1.6, p=0.04).
Conclusions: SMAD4 gene mutation in HHT patients is independently associated with a higher risk of aortic root and ascending aortic dilation as compared to other HHT patients and non-HHT controls.
Keywords: Aortic dilatation; Computed tomography; Hereditary haemorrhagic telangiectasia; SMAD4; TGF-β.
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