Use of Arterial Transfer Functions for the Derivation of Central Aortic Waveform Characteristics in Subjects With Type 2 Diabetes and Cardiovascular Disease: Response to Hope et al.

We read with interest the recent article by Hope et al. (1) concerning the noninvasive estimation of central aortic pressure waveforms in subjects with type 2 diabetes. We entirely agree with their view that aortic rather than brachial artery pressure is likely to be of greater prognostic value, as are indexes such as aortic augmentation index. We would also agree that the data presented in the article clearly indicate that there was a substantial difference between invasively measured and derived aortic systolic pressure. However, the authors’ conclusions seem overstated and may be misinterpreted by nonspecialist readers. The transfer function used by Hope et al. is actually their own and not that which is used in the “commercial devices” that they refer to in their introduction. Indeed, they offer no data to suggest that other transfer functions are unreliable in subjects with diabetes. Therefore, all that Hope et al. can actually conclude is that their own generalized transfer function is unreliable in subjects with diabetes. Thus, other investigators may be better off using “commercial devices” rather than the seemingly discredited transfer function of Hope et al.