Independent association of plasma leptin levels and left ventricular isovolumic relaxation in uncomplicated hypertension

Background: On the basis of evidence of plasma leptin (LE) effects on cardiovascular system, we assessed possible association of LE and Doppler-derived left ventricular (LV) diastolic function in arterial hypertension. Methods: Doppler echocardiography, blood sample for fasting plasma LE levels, and euglycemic hyperinsulinemic glucose clamp were performed on 15 healthy insulin-sensitive men and 40 newly diagnosed hypertensive men, who were divided into two groups according to insulin sensitivity degree: 15 insulin sensitive (IS) and 25 insulin resistant (IR) individuals (whole body glucose disposal >33.3 and <33.3 μmol/kg, respectively). Results: The IR hypertensives had significantly higher body mass index (BMI), waist/hip ratio, LE and LV mass index than the other two groups. IR hypertensives had lower LE (even after adjusting for BMI and waist/hip ratio) and among LV diastolic indexes, lower E peak velocity (P< .05) and longer isovolumic relaxation time (IVRT) (P< .001) in comparison to IR hypertensives. IR hypertensives had the lowest E/A ratio (0.88 ± 0.2) compared to IS patients (1.03 ± 0.1 P< .05) and controls (1.31 ± 10.2 P< .001). By multiple linear regression analyses performed both in the overall population and hypertensives, LV mass index and LE were independently associated to IVRT (R2 = 0.41 in overall population, R2 = 0.42 in hypertensives, both P< .0001), whereas age, heart rate, diastolic and systolic blood pressure (BP), BMI, waist/hip ratio, and insulin action were not significant. Conclusions: Our study underscores an independent association of increased plasma LE and lengthening of isovolumic relaxation in uncomplicated hypertension. Further studies will need to understand the conditions underlying both these phenomena.