The Multicenter Isradipine Diuretic Atherosclerosis Study (MIDAS)-Reply

In Reply. —Regarding the comments by Dr Kaufman on the ultrasound data, the ultrasound instrument used in MIDAS was Biosound 2000 II spectrum analysis with 8-MHz annular arrays (approximate axial resolution, 0.3 mm). This was defined in the original protocol and previously published. 1 Kaufman notes that the intimal-medial thickness differences in MIDAS are less than the axial resolution of ultrasound equipment, and therefore the analyses may overstate the ability of these instruments to determine the fine differences reported. The differences presented were calculated, not measured, by comparing within-group or between-group intimal-medial thickness data. That it is not possible to directly measure these differences does not affect the validity or appropriateness of determining their presence or use in analyses of grouped data. The comments by Dr Abt concerning the statistical significance (or lack thereof) of the difference in cardiovascular events between patients treated with hydrochlorothiazide and isradipine in the MIDAS trial seem