Effect of insulin resistance on left ventricular hypertrophy and dysfunction in essential hypertension

Abstract

In hypertensive patients, the relationships between glucose tolerance and left ventricular hypertrophy (LVH) and left ventricular diastolic function (LVDF) have been described in several reports. In this study, we examined the relationships between insulin resistance and LVH and LVDF in hypertensive patients from the therapeutic perspective. The study participants were essential hypertensive patients with impaired glucose tolerance (IGT-HT, n = 26), hypertensive patients with normal glucose tolerance (NGT-HT, n = 39), and normotensive control individuals (n = 18). Insulin resistance was evaluated by the insulin suppression test by use of the steady-state plasma glucose (SSPG) level. Left ventricular mass index (LVMI) and LVDF, which was determined by the E: A ratio, were estimated by echocardiography. Temocapril, an angiotensin-converting enzyme inhibitor, was administered in an open, non- randomized manner with a mean dose of 2.8 ± 0.2 mg/ day, and the mean administration period was 18 weeks. The systolic and diastolic blood pressure, the LVMI, and the SSPG level were significantly higher in the hypertensive patients than in the control individuals. The mean systolic and diastolic blood pressures were significantly decreased by treatment with Temocapril. Before treatment, stepwise regression analysis showed that SSPG is an independent predictor for LVMI and LVDF. After treatment, the changes in LVMI (D-LVMI; %) (−15.1 ± 1.5), the changes in LVDF (D-E: A; %) (−38.2 ± 4.1), and the changes in insulin resistance (DSSPG; %) (−13.7 ± 1.7) were significantly higher in the IGT-HT group than in the NGT-HT group (−11.4 ± 1.1, −18.1 ± 1.7, −9.4 ± 1.4, respectively), and the D-SSPG was an independent predictor for D-LVMI and D-E: A. The results of this study indicate that insulin resistance is an important factor affecting LVH and LVDF.