Effects of Ramipril on Arterial Stiffness To the Editor: The study by Ahimastos et al1 described reduction in aortic pulse wave velocity (PWV) with 10 mg daily ramipril; this was not associated with any fall in mean brachial artery pressure. There is a curious anomaly in this study, which casts doubt on the conclusions. Whereas the authors report no change in mean pressure with 10 mg ramipril compared with placebo, there was a highly significant reduction in brachial systolic (5.4 mm Hg) and diastolic (6.3 mm Hg) pressures. How is it possible for both systolic and diastolic pressures to fall but mean pressure to be maintained? We have never seen such a phenomenon. We do, however, have serious reservations about using the Dinamap Vital Signs Monitor to measure cuff brachial pressure, because this device has been shown to be inaccurate in a number of studies, especially for diastolic blood pressure.2 If related to diastolic pressure at the foot of the waveform (from which PWV is measured), the fall in aortic PWV may be largely attributed to passive reduction in distending pressure. We, and others, certainly have noted this.3–5 Further, the authors calculated carotid systolic pressure from brachial mean and diastolic pressure. Such calculation is based on equivalence of mean pressure and diastolic pressure in the carotid and brachial arteries. If one is incorrect, such a calculation will be erroneous. Views on direct effects of ramipril and other drugs on aortic stiffness will remain unclear until these technical issues are addressed. There is no doubt that ramipril and similar drugs reduce aortic augmentation3–5 and, hence, arterial compliance as measured by Ahimastos et al.1 There is, however, doubt on any direct effect on aortic PWV, especially when based on anomalous recordings of arterial pressure.