Arterial Wall Properties and Womersley Flow in Fabry Disease

BACKGROUND Fabry disease is an X-linked recessive lysosomal storage disease resulting in the cellular accumulation of globotriaosylceramide particularly globotriaosylceramide. The disease is characterized by a dilated vasculopathy with arterial ectasia in muscular arteries and arterioles. Previous venous plethysomographic studies suggest enhanced endothelium-dependent vasodilation in Fabry disease indicating a functional abnormality of resistance vessels. METHODS We examined the mechanical properties of the radial artery in Fabry disease, a typical fibro-muscular artery. Eight control subjects and seven patients with Fabry disease had a right brachial arterial line placed allowing real time recording of intra-arterial blood pressure. Real time B-mode ultrasound recordings of the right radial artery were obtained simultaneously allowing calculation of the vessel wall internal and external diameter, the incremental Young's modulus and arterial wall thickness. By simultaneously measurement of the distal index finger-pulse oximetry the pulse wave speed was calculated. From the wave speed and the internal radial artery diameter the volume flow was calculated by Womersley analysis following truncation of the late diastolic phase. RESULTS No significant difference was found between Fabry patients and controls for internal or external arterial diameters, the incremental Young's modulus, the arterial wall thickness, the pulse wave speed and the basal radial artery blood flow. Further, no significant difference was found for the radial artery blood flow in response to intra-arterial acetylcholine or sodium nitroprusside. Both drugs however, elevated the mean arterial flow. CONCLUSIONS The current study suggests that no structural or mechanical abnormality exists in the vessel wall of fibro-muscular arteries in Fabry disease. This may indicate that a functional abnormality downstream to the conductance vessels is the dominant feature in development Fabry vasculopathy.