Nailfold Videocapillaroscopic Findings in Bradykinin-Mediated Angioedema.

BACKGROUND AND OBJECTIVE: Hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) and acquired angioedema related to ACE inhibitors (ACEI-AAE) are types of bradykinin-mediated angioedema without wheals characterized by recurrent swelling episodes. Recent evidence suggests that a state of "vascular preconditioning" predisposes individuals to attacks, but no data are available on the possible structural alterations of the vessels. Objective: This study aims at evaluating the features of the nailfold capillaries to highlight possible structural anomalies in patients affected by C1-INH-HAE in comparison with the healthy population and ACEI-AAE patients in comparison with hypertensive controls. METHODS: With nailfold videocapillaroscopy (NVC), we assessed: apical, internal, and external diameter, loop length, intercapillary distance, capillary density, distribution, and morphology. Plasma levels of vascular endothelial growth factor (VEGF)-A, VEGF-C, angiopoietin (Ang)1, and Ang2 were also measured. RESULTS: C1-INH-HAE patients (n = 34) had significant structural alterations of the capillaries compared to healthy controls (n = 28): greater intercapillary distance (216 vs 190 microm), increased apical, internal, and external diameter (28 vs 22 microm; 22 vs 20 microm; and 81 vs 65 microm, respectively), decreased density (4 vs 5 capillaries/mm2), more irregular capillary distribution, and more tortuous morphology. Apical diameter was enlarged in patients with >/=12 attacks/year. In ACEI-AAE patients, NVC showed no alterations versus hypertensive controls. NVCs performed in two C1-INH-HAE patients during attacks showed no changes compared to the remission phase. CONCLUSIONS: C1-INH-HAE patients have important structural capillary alterations, confirming the involvement of microcirculation in the pathogenesis of angioedema.