The Multicenter Isradipine Diuretic Atherosclerosis Study (MIDAS)

The Multicenter Isradipine Diuretic Atherosclerosis Study (MIDAS) used high resolution ultrasound to compare the rate of change of carotid artery intimal medial thickness (IMT) and atherosclerosis between two groups of hypertensives receiving either isradipine or hydrochlorothiazide. This was a double blinded, active control trial that enrolled 883 patients who were followed for 3 years. Patients whose blood pressure was not controlled on the blinded medication were given open label enalapril. Inclusion criteria were either sex, mild to moderate hypertension, age >40, localized carotid arterial IMT >1.3 and <3.5 mm, LDL >130 and <189. The primary endpoint was a comparison of the change in arterial wall thickness between the two groups. This is the first trial to use ultrasound measurements of early atherosclerotic lesions as an end point. The secondary objectives were evaluation of safety, changes in blood lipids, cardiovascular events, echocardiographic left ventricular mass, and quality of life. The demographics and patient characteristics will be presented. The data on the ultrasound measurements at baseline and their relationship to patient characteristics will also be presented. This study demonstrated that the IMT could be reproducibly measured by high resolution ultrasound using a standardized scanning and reading protocol.