Abstract P223: Vitamin D Supplementation Improves Measures Of Arterial Stiffness And Vascular Function In Adolescents Suffering From Orthostatic Intolerance

Abstract

Background: In previous work we identified a group of adolescents with orthostatic intolerance (OI) presenting as postural orthostatic tachycardia syndrome or syncope with impairment in autonomic and vascular response upon head up tilt. Low vitamin D level correlated with the severity of symptoms. In this pilot study we hypothesized that vitamin D supplementation will improve the vascular function in these adolescents. Methods: A cohort of twenty Adolescents (mean age= 16.2 years, 4 males) who are vitamin D deficient had a non-invasive measurements of brachial BP, aortic BP, augmentation index at heart rate of 75 beats per minute (AIx75), and carotid-femoral pulse wave velocity (cf-PWV) using the SphygmoCor XCEL System at baseline and after two months of vitamin D supplementation (2000-5000 IU daily based on baseline level). Both right and left side ankle pressure and ankle brachial index (ABI) were assessed using COLIN VP-1000 vascular profiling system. Impedance Cardiography (ICG) was used to estimate total arterial compliance (TAC) and thoracic fluid content (TFC) in supine position at rest and after hand grip challenge. Results: As shown in the table. Compared to baseline, vitamin D supplementation increased vitamin D level, increased TAC and TFC at baseline and under stress challenge. It also tended to reduced AIx75 and cf-PWV and reduced both right and left ankle pressure and ABI Conclusions: Vitamin D supplementation improved different measures of vascular function in adolescent. These data provides evidence of potential therapeutic benefit of vitamin D supplementation for patients suffering from orthostatic intolerance who are vitamin D deficient.