Inverse relationship between cutaneous vascular conductance and augmentation index after administration of nitroglycerin (1156.9)

Augmentation index (AIx) is a marker of wave reflection and arterial stiffness, derived from a central blood pressure waveform. AIx is acutely reduced with sublingual nitroglycerin (NG) via endothelium independent dilation. In this way NG may also influence the cutaneous vascular conductance (CVC), which has a high capacity to influence central hemodynamics and blood pressure. The relationship between cutaneous vascular conductance and AIx is unknown. We examined alterations in AIx and CVC in ten older individuals (62 ± 8 yrs, 169 ± 11 cm, 71 ± 9 kg) following 3 min sublingual administration of NG (400 µg). AIx and vascular hemodynamics were measured at baseline and every 20 seconds for 20 minutes following NG administration. In the 5 min period following NG administration AIx was reduced by 45% from 27 ± 10 % at baseline to 15 ± 14 % (P = 0.000), while CVC increased 32% over the same period from 27 ± 6 AU/mmHg at baseline to 36 ± 12 AU/mmHg (P = 0.014). Mean arterial pressure was unchanged throughout (P > 0.05). Throughout the 20 minute period following NG administration, alterations in AIx and CVC were inversely related (r = ‐0.76; P < 0.001). A relationship between AIx and CVC may suggest an interplay between the cutaneous vasculature and surrogate measures of arterial stiffness that warrants further investigation. Such findings may have implications for our understanding of cutaneous vascular control and cardiovascular risk.