Follow-up interval for small untreated pulmonary arteriovenous malformations in hereditary haemorrhagic telangiectasia.

AIM: To investigate the natural history of untreated small (<3 mm) and microscopic pulmonary arteriovenous malformations (PAVMs) in hereditary haemorrhagic telangiectasia (HHT) in order to discern the optimal frequency of follow-up thoracic computed tomography (CT).

MATERIALS AND METHODS: A retrospective analysis was performed on the follow-up data for definite and suspected HHT patients with untreated PAVMs.

RESULTS: For small PAVMs in definite HHT (n=13), PAVM enlargement was identified in one patient (1/13, 7.7%) after 10.7 years follow-up and was successfully treated using transcatheter embolisation (TCE). For microscopic PAVMs in definite HHT (n=28), two patients (2/28, 7%) developed small asymptomatic PAVMs, which did not meet the size criteria for TCE after 6.8 years of follow-up. For small PAVMs in suspected HHT (n=5), feeding artery enlargement was seen in one patient (1/5, 20%) after 7.9 years, but again, this did not meet the size criteria for embolisation. No macroscopic PAVM development was identified after a median follow-up of 5.4 years in suspected HHT with microscopic PAVMs (n=20).

CONCLUSION: For small and microscopic PAVMs in HHT, PAVM enlargement was found to be more infrequent than would be expected based on current guidelines; therefore, potentially challenging the current surveillance imaging recommendation of a repeat thoracic CT every 5 years.