Skin microvascular reactivity and subendocardial viability ratio in relation to dyslipidemia and signs of insulin resistance in non-diabetic hypertensive patients

Abstract

Objective: The aim of this study was to evaluate the influence of dyslipidemia and insulin resistance for the development of microvascular dysfunction in non-diabetic primary hypertension. Methods: Seventy-one patients with untreated primary hypertension were included. Skin microvascular reactivity was evaluated by laser Doppler fluxmetry with iontophoresis (acetylcholine, ACh and sodium nitroprusside, SNP) and heat-induced hyperemia. Myocardial microvascular function was estimated by the subendocardial viability ratio (SEVR) calculated from pulse wave analysis and applanation tonometry. Triglyceride x glucose (TyG index) and triglyceride/HDL cholesterol ratio were used as measurements of insulin resistance. Results: Skin microvascular dysfunction was associated with low HDL cholesterol, where Ach-mediated peak flux (r =.27, p =.025) and heat-induced peak flux (r =.29, p =.017) related to HDL cholesterol levels. ACh peak flux was inversely related to TG/HDL ratio (r = –.29, p =.016), while responses to local heating and SNP did not. SEVR did not relate to HDL and was unrelated to markers of insulin resistance. These findings were confirmed by multivariable analyses, including potential confounders. Conclusions: Early microvascular dysfunction can be detected in non-diabetic hypertensive patients and is related to dyslipidemia and to signs of insulin resistance, thus predicting future cardiovascular risk.