MIDAS: rationale, design and descriptive data of trial patients. The MIDAS Research Group

Certain classes of antihypertensive drugs, such as calcium antagonists, appear to have antiatherogenic properties, as shown in animal models. In these experimental models, only isradipine, a potent new dihydropyridine calcium antagonist, has shown an antiatherogenic effect in doses compatible with that recommended for antihypertensive treatment in humans. The Multicenter Isradipine/Diuretic Atherosclerosis Study (MIDAS) was designed to assess the efficacy of isradipine (2.5 or 5.0 mg twice daily) compared with hydrochlorothiazide (HCTZ) in reducing the rate of progression of atherosclerotic plaque in carotid arteries, as measured by B-mode ultrasonography. MIDAS is the first clinical trial of hypertension designed to test the hypothesis that antihypertensive drug treatment may have a favourable effect on the progression of atherosclerosis in humans. MIDAS is a double-blind, randomized, controlled clinical trial involving 883 patients. The primary endpoint is the observed change in the rate of progression of the intimal-medial wall thickness of the carotid arteries, as measured quantitatively by B-mode ultrasonography over time. Changes in the mean maximum intimal-medial thickness (IMT) at 12 points in the carotid arteries (near and far walls of the common carotid, the carotid bifurcation, and internal carotid segments on both right and left sides of the neck) were measured over a 3-year period. At baseline, the mean age of the participants was 58.5 years. The mean systolic and diastolic blood pressures were, respectively, 149.8 and 96.5 mmHg. The mean duration of hypertension was 10 years.(ABSTRACT TRUNCATED AT 250 WORDS)