RADIAL-DIGITAL PULSE WAVE VELOCITY: RESPONSE OF SMALL ARTERIES TO A MODIFICATION OF ARTERIAL STIFFNESS GRADIENT INDUCED BY NITROGLYCERIN

Abstract

Objective: We previously demonstrated that it is possible to modulate the arterial stiffness gradient with the administration of nitroglycerin (NTG). This alteration of the physiological stiffness gradient would increase the transmission of greater pulsatility to the microcirculation, thus explaining the damage to the pressure-sensitive organs. We aimed to describe small conducting arteries response following the pharmacological alteration of the stiffness gradient using regional stiffness of the hand (radial-digital PWV, rd-PWV). Design and method: The simultaneous application of piezoelectric sensors (Complior) at the level of the carotid ®, the radial artery ®, and the tip of the index finger (d) was used to calculate the rd-PWV by the following formula (rd-PWV = cd-cr distances/cd-cr transit time). Rd-PWV was obtained before and 4 minutes after a sublingual administration of 0.4 mg of NTG, in healthy adults (controls, n = 23) and patients with moderate chronic kidney disease (CKD, n = 18). Changes in arterial stiffness pre-post NTG and comparisons between the two groups were analyzed using generalized estimating equations. Results: Pre NTG, despite similar cr-PWV, rd-PWV in CKD seemed lower than controls (3.7 ± 1.6 m/s vs. 4.6 ± 1.5 m/s, p = 0.067). This difference between the two groups faded (p = 0.865) after adjusting for age, where the standardized coefficient B of age = -0.407 (p = 0.037). Post NTG, cr-PWV decreased in both groups (p < 0.001) while rd-PWV increased similarly (no interaction, p = 0.111)), between controls (from 4.62 ± 1.49 m/s to 5.94 ± 2.29m /s, p < 0.001) and CKD (from 3.71 ± 1.60 m/s to 5.18 ± 2.12m/s, p < 0.001). There was no difference in changes of brachial pressures between the two groups. Conclusions: Again, we observed opposite changes in arterial stiffness in two different arterial territories following the administration of NTG. In contrast with cr-PWV, regional stiffness of the hand increase after NTG administration. Rd-PWV is a new approach for the measurement of the regional stiffness of small arteries that could open the way to a better hemodynamic understanding of the consequences of the inversion of the stiffness gradient.