Conditions: Insulin Sensitivity Aortic Compliance Diastolic Function
Allocation: RANDOMIZED | Intervention model: SINGLE_GROUP
Enrollment: 24
Healthy volunteers: no

Brief summary:
This study is an investigation of the effect of commonly prescribed anti-hypertensive agents on insulin sensitivity, diastolic function and aortic compliance. The aims of the study are as follows:

Specific Aim 1: To determine in insulin resistant, hypertensive subjects if renin inhibition for 12 weeks modifies glucose homeostasis and insulin sensitivity.

To accomplish this specific aim, we will use three approaches: a fasting HOMA Index; and a three hour glucose tolerance test. Only hypertensive subjects with insulin resistance, as assessed by HOMA index will be enrolled in the study. Insulin resistance will be assessed basally and after twelve weeks of treatment with either a calcium channel blocker with placebo, or calcium channel blocker with a renin inhibitor, or a calcium channel blocker with a renin inhibitor and an angiotensin receptor antagonist.

Specific Aim 2: To determine in insulin resistant, hypertensive subjects if renin inhibition for 12 weeks modifies diastolic function and aortic compliance response to dietary sodium intake.

The same protocol and subjects will be used as defined in Specific Aim 1. Myocardial relaxation velocity (tissue Doppler imaging at the mitral annulus) and aortic compliance (characteristic aortic impedance) will be measured at baseline and then after acute and chronic renin inhibition:

1. Acute effect of renin inhibition: Hemodynamic measurements will be obtained on both high and low dietary sodium intake conditions (\~1 week each) before and after a single dose of a renin inhibitor.
2. Chronic effect of renin inhibition: Hemodynamic measurements will be obtained at baseline and after 12 weeks of each of the three drug treatment arms above.

The study lasts 12 weeks and plans to study 45 hypertensive adults over the next two years.

Detailed description:

Arms:
arm 1: Valsartan 150 mg and Aliskiren (150 mg followed by force titration to 300 mg) arm 2: None arm 3: Only taking Amlodipine

Interventions: intervention 1: Aliskiren intervention 2: Valsartan and Aliskiren intervention 3: Amlodipine
Intervention descriptions: intervention 1: Aliskiren 150 mg daily for 10 weeks, force titrated after initial 2 weeks. intervention 2: Subject taking combination of valsartan and aliskiren. intervention 3: Taking Amlodipine as prescribed by MD for management of high blood pressure.

Protocol document: