PS-BPC02-7: RADIAL-DIGITAL PULSE WAVE VELOCITY: STIFFNESS OF SMALL CONDUIT ARTERIES INCREASES AFTER NITROGLYCERIN ADMINISTRATION

Abstract

Objective: The alteration of the physiological stiffness gradient within larger vessels would increase the transmission of greater pulsatility to the microcirculation, thus explaining the damage to the pressure-sensitive organs. We aimed to describe the response of small conduit arteries of the hand (radial-digital PWV, rd-PWV) following the pharmacological alteration of the stiffness gradient using nitroglycerin. Design and method: Simultaneous application of piezoelectric sensors (Complior) at the level of the carotid (c), the radial artery (r) and the tip of the index finger (d) was used to calculate the rd-PWV by the following formula (rd-PWV = cd-cr direct distances/cd-cr transit times). Rd-PWV was obtained before and 4 minutes after a sublingual administration of 0.4 mg of NTG, in healthy adults (controls, n = 36) and patients with moderate chronic kidney disease (CKD, n = 30). Changes in arterial stiffness pre-post NTG and comparisons between the two groups were analyzed respectively with paired or independent samples t-tests. Results: Compared to controls, the CKD group was older (69 ± 15 years vs. 41 ± 20 years) and more hypertensive. Despite similar cd-PWV and cr-PWV, rd-PWV was significantly lower in CKD than in controls (3.6 ± 1.4 m/s vs. 4.5 ± 1.8 m/s, p = 0.024), but this difference faded (p = 0.145) after adjustment for age. Post NTG, brachial blood pressure decreased and heart rate increased similarly between groups (see Table 1). Cr-PWV decreased after NTG (both groups p < 0.001) while rd-PWV increased in controls (from 4.62 ± 1.49 m/s to 5.94 ± 2.29 m/s, p < 0.001) and in CKD (from 3.71 ± 1.60 m/s to 5.18 ± 2.12 m/s, p < 0.001), in a similar extent (p = 0.111 for interaction term). Cd-PWV significantly increased post-NTG only in the CKD group (p = 0.009). Conclusions: Again, we observed opposing changes in the regional stiffnesses of two distinct vascular territories following the administration of a vasodilator. Here, the two segments were mid-size and small conduit muscular arteries. This technique, adapted by our team for short peripheral arterial segments, may broaden our understanding of the consequences of the inversion of the stiffness gradient.