Objective: To compare the rate of progression of mean maximum intimal-medial thickness (IMT) in carotid arteries, using quantitative B-mode ultrasound imaging, during antihypertensive therapy with isradipine vs hydrochlorothiazide.
Design: Randomized, double-blind, positive-controlled trial.
Setting: Nine medical center clinics.
Population: A total of 883 patients with baseline mean +/- SD systolic and diastolic blood pressure (SBP and DBP, respectively) of 149.7 +/- 16.6 and 96.5 +/- 5.1 mm Hg, age of 58.5 +/- 8.5 years, and maximum IMT of 1.17 +/- 0.20 mm.
Interventions: Twice daily doses of isradipine (2.5-5.0 mg) or hydrochlorothiazide (12.5-25 mg). MAIN OUTCOME MEASURE (PRIMARY END POINT): Rate of progression of mean maximum IMT in 12 carotid focal points over 3 years.
Results: There was no difference in the rate of progression of mean maximum IMT between isradipine and hydrochlorothiazide over 3 years (P=.68). There was a higher incidence of major vascular events (eg, myocardial infarction, stroke, congestive heart failure, angina, and sudden death) in isradipine (n=25; 5.65%) vs hydrochlorothiazide (n=14; 3.17%) (P=.07), and a significant increase in nonmajor vascular events and procedures (eg, transient ischemic attack, dysrhythmia, aortic valve replacement, and femoral popliteal bypass graft) in isradipine (n=40; 9.05%) vs hydrochlorothiazide (n=23; 5.22%) (P=.02). At 6 months, mean DBP decreased by 13.0 mm Hg in both groups, and mean SBP decreased by 19.5 mm Hg in hydrochlorothiazide and 16.0 mm Hg in isradipine (P=.002); the difference in SBP between the 2 groups persisted throughout the study but did not explain the increased incidence of vascular events in patients treated with isradipine.
Conclusion: The rate of progression of mean maximum IMT in carotid arteries, the surrogate end point in this study, did not differ between the 2 treatment groups. The increased incidence of vascular events in patients receiving isradipine compared with hydrochlorothiazide is of concern and should be studied further.