Prevalence and severity of arterial calcifications in pseudoxanthoma elasticum (PXE) compared to hospital controls. Novel insights in to the vascular phenotype of PXE

BACKGROUND AND AIMS: Pseudoxanthoma elasticum (PXE) is a monogenetic disorder with progressive calcifications of the skin, the Bruch's membrane in the eyes and the arterial wall. Vascular disease is considered to be very prevalent, but the whole-body distribution of arterial calcifications in PXE is unknown. We aimed to systematically investigate arterial calcifications in PXE.

METHODS: We included 104 PXE patients from the Dutch PXE cohort and 93 hospital controls. All subjects underwent full-body low-dose CT scans without contrast. To investigate the prevalence and severity of arterial calcification per arterial location, CT scans were scored using a reproducible semi-quantitative scale with four calcification categories (interobserver kappa 0.54-0.99).

RESULTS: PXE patients (38/104 males) were 54 ± 13 years and controls (45/93 males) 54 ± 16 years old. Arterial calcifications were significantly more common in PXE patients in the intracranial internal carotid artery (75% vs. 44%), the arteries of the arms (20% vs. 3%), the femoral-popliteal arteries (74% vs. 44%) and the subpopliteal arteries (84% vs. 38%). In these arteries, calcification scores also indicated more severe calcification. No significant differences in prevalence of arterial calcification were observed in other arterial beds such as the coronary arteries (45% vs. 43%, p = 0.776), the carotid arteries (52% vs 46%, p = 0.476) and the abdominal aorta (71% vs. 63%, p = 0.287). Analyses using patients younger than 55 years only, showed similar differences in prevalence of arterial calcifications between PXE patients and controls, with most pronounced calcifications in the arteries of the lower legs (67% vs. 8%). Similar patterns were observed in those without concomitant diabetes or renal dysfunction.

CONCLUSIONS: In PXE, a vascular phenotype can be identified with a distribution of arterial calcifications that is clearly distinct from hospital controls and involves arterial calcifications in the legs, the intracranial internal carotid arteries and the arteries of the arms.