O-15: Skin capillary density and plasma endothelin levels in hypertensive and normotensive patients with anginal chest pain and normal coronary arteriograms

Abstract

Patients with anginal chest pain and normal coronary arteries (CP-NCA) may have reduced coronary blood flow reserve, abnormal endothelium-dependent vasodilator responses and higher levels of plasma endothelin-1. We recently showed that skin capillary density is lower in patients with CP-NCA. The aim of this study was to examine the relationship between capillary density (measured by intra-vital microscopy before and after maximisation with venous congestion) and flow-mediated dilatation (FMD) measured by brachial artery Doppler ultrasound and plasma endothelin levels. We studied 19 patients With CP-NCA [11 were hypertensive (age 60 ys, sitting BP on treatment 145/82mmHg) and 8 were normotensive (age 60 ys, BP 128/75mmHg)] and 9 healthy controls (age 59 ys, BP 125/78mmHg). Mean capillary density was significantly lower in patients with CP-NCA independent of their BP compared to healthy controls, both at baseline [55±5 in hypertensives, 61±3 in normotensive versus 73±4 in controls, p<0.001 ANOVA], and after maximisation [60±5, 67±3 versus 86±4 respectively, p<0.0001]. FMD was higher in controls than in normotensive CP-NCA who in turn had higher values than hypertensive CP-NCA (5.561 versus 4.329 versus 3.646%, p=0.056. Capillary density was markedly lower with higher plasma endothelin-1 levels in subjects with CP-NCA (r= - 0.7, p=0.01). In conclusion we confirmed a significant reduction in baseline and maximal skin capillary density in patients with CP-NCA independent of blood pressure. Our findings suggest that plasma endothelin-1 may be implicated in the pathogenesis of capillary rarefaction in this syndrome.

Capillaries, Endothelin, Microcirculation