Augmentation of central arterial pressure in type 1 diabetes

OBJECTIVE - Atherosclerosis is more severe in individuals with diabetes. Wh ether diabetic subjects have accelerated arterial hardening (i.e., arterios clerosis) is less clear. Arteriosclerosis increases pulse-wave velocity and can augment central arterial pressure due to early wave reflection. The ai m of this study was to determine whether subjects with type 1 diabetes had evidence of increased arterial stiffness by using pulse-wave analysis. RESEARCH DESIGN AND METHODS- Radial artery pressure waveforms were obtained noninvasively by applanation tonometry (PWV Medical Blood Pressure Analysi s System, Sydney). A central aortic waveform can be derived by using a tran sfer function used in previous studies during cardiac catheterization. A to tal of 89 subjects with type 1 diabetes (46 men and 43 women, aged 34.0 +/- 11.0 years, duration of diabetes 13.1 years [interquartile range 5.8-24.3] , HbA(1c) 8.2 +/- 1.7%) and 95 control subjects (44 men and 51 women, aged 36.1 +/- 12.0 years) were studied. The central aortic waveform allowed the determination of 1) the aortic augmentation index (AAI), a parameter that r eflects the degree to which central arterial pressure is augmented by wave reflection, and 2) the subendocardial viability ratio (SEVR), which is a me asure of myocardial perfusion relative to cardiac workload. RESULTS- In multivariate analysis, diabetes was an important determinant of AAI (P = 0.001). The higher AAI was mainly evident in the men, for whom di abetes was a highly significant covariate (P = 0.006); this was not the cas e for diabetic women (P = 0.2). Nondiabetic men had a lower AAI than nondia betic women (103.7 +/- 18.6 vs. 117.0 +/- 22.3%, respectively, P = 0.002), but this difference was abolished by diabetes (110.7 +/- 18.5 vs. 116.1 +/- 18.7%, respectively, P = 0.2). Subjects with type 1 diabetes had a signifi cantly lower mean SEVR compared with control subjects (139.2 +/- 28.3 vs. 1 63.6 +/- 27.4%, respectively P < 0.0001). In multivariate analysis, diabete s was an important determinant of SEVR (P = 0.001). A significant interacti on between diabetes and age was evident (P = 0.0001), which suggests that t he effect of age is modified by diabetes. CONCLUSIONS - These findings suggest that central systolic blood pressure i s increased in relatively young individuals with type 1 diabetes, although myocardial perfusion related to cardiac workload is decreased. These change s can be explained by more rapid pulse-wave velocity resulting from arteria l stiffening.