Use of Arterial Transfer Functions for the Derivation of Central Aortic Waveform Characteristics in Subjects With Type 2 Diabetes and Cardiovascular Disease: Response to Avolio, Cockcroft, and O’Rourke

Avolio, Cockcroft, and O’Rourke (1) raise some valid concerns regarding the approach taken by Hope et al. (2) in generating and validating an arterial transfer function in subjects with diabetes. The rigorous evaluation and validation process, which undoubtedly supported the Food and Drug Administration approval of the SphygmoCor SCOR-Px device, could be used as a model for parallel evaluations in specific populations of interest. Despite these authors’ assurances of universal applicability, however, given the profound effects of diabetes on all dimensions of the vascular tree, it does seem reasonable to specifically test whether generalized transfer functions are valid in subjects with diabetes. The manuscript by Hope et al. was of value in that it raises questions about the validity of this tool in this setting. We are in full agreement with Avolio, Cockcroft, and O’Rourke that appropriate validation of the generalized transfer function in subjects with diabetes is required before the use of this tool in research or clinical applications can be advocated.