Diurnal pattern of plasma endothelin-1: effect on endothelium-dependent vasodilatation in patients with stable angina pectoris

ABSTRACT

This study included two groups of patients Group I included 20 patients with stable angina pectoris [SA] [18 men and 2 women, aged 50.51 +/- 8.29 years] and group II included 20 healthy subjects [17 males and 3 females, aged 48.11 +/- 6.31 years] taken as a control group. Flow-mediated vasodilatation [FMD] of the brachial artery [a surrogate for endothelium-dependent vasodilatation] was determined by ultrasound at 8 a.m. and 8 p.m. Also, carotid artery intima-media thickness [IMT] was determined by ultrasound. The plasma levels of C- reactive protein [CRP] and ET-1 were determined at 8 a.m. and 8 p.m. The study included that the normal subjects had diurnal variation in endothelium-dependent vasodilatation that may counteract other, potentially adverse, diurnal variations in the hemodynamic and other parameters. In contrast, patients with SA showed a loss of this protective mechanism. No diurnal variation in plasma CRP was found to explain this finding. Diurnal variation in plasma ET-1 levels is likely one of the mechanisms involved in the pathogenesis of this phenomenon