Systemic Endothelial Dysfunction in Adults With Cyanotic Congenital Heart Disease

Abstract

Background— Secondary erythrocytosis results in increased shear stress in cyanotic congenital heart disease (CCHD), which may modify the balance between vasodilators and vasoconstrictors and affect systemic endothelial function. Because no data are available on systemic vasomotion, systemic endothelial function and nitric oxide (NO) availability were investigated in CCHD patients. Methods and Results— Responses to arterial endothelium-dependent (acetylcholine [Ach]) and -independent (sodium nitroprusside [SNP]) vasodilation, NO synthase blockade ( N ^G -monomethyl- l -arginine [ l -NMMA]), endothelin-1 (ET-1), and ET-1 receptor blockade by BQ-123 in 11 CCHD patients (O ₂ saturation −1 · 100 mL ⁻¹ of forearm volume [FAV], P 0.1), the response to Ach was markedly reduced in CCHD (maximal increase in FBF, 2.8±0.8 versus 37.5±4.4 mL · min ⁻¹ · 100 mL ⁻¹ of FAV; P P P Conclusions— Systemic endothelial dysfunction is evident in CCHD patients as shown by strikingly reduced endothelial vasodilation to Ach. The response to exogenous ET-1 is reduced, possibly because of elevated endogenous ET-1 levels, but the effects of endogenous ET-1 on arterial tone are not enhanced, as indicated by the similar response to ET-1 blockade.