Aortic pressure-diameter relation in patients with non-insulin dependent diabetes mellitus: new insights

Aims/hypothesis. Type II (non-insulin-dependent) diabetes mellitus is assoc iated with macrovascular disease. Therefore, we investigated the aortic ela stic properties by a new method in patients with diabetes and control patie nts matched with them. Methods. Patients with Type II diabetes (n = 20) and control patients witho ut diabetes (n = 21) were enrolled in the study. All patients had coronary artery disease. Instantaneous aortic diameter was measured by an intravascu lar catheter developed in our institution. Instantaneous aortic pressure wa s measured simultaneously at the same aortic level with a catheter-tip micr omanometer, Thus, aortic pressure-diameter loops were obtained and slope an d intercept were calculated Aortic distensibility, stiffness constant and e nergy loss were also calculated. Results. The mean age and the heart rate were similar in the two groups. Th e pulsatile changes in aortic diameter were greater in the control group (0 .94 +/- 0.4 vs 1.28 +/- 0.4 mm, p < 0.01). The stiffness of the aortic wall was greater in diabetic patients as indicated from the following variables : the distensibility was less in patients with diabetes (1.16 +/- 0.6 vs 1. 95 +/- 0.9 cm(2).dyne(-1).10(-6), p<0.01); the slope was greater (113.4+/-1 20.1 vs 51.61 +/-3.3 mmHg/mm, p<0.01) and the intercept was less in diabeti c patients (-2301.9 +/- 2692.9 vs -1114.45 +/- 295.6 mmHg, p < 0.01); the s tiffness constant was greater in patients with diabetes (1.66 +/- 1.8 vs 0. 77 +/- 0.8 mm(-1), p < 0.03). Aortic energy loss was, however, similar betw een the groups. Conclusion/interpretation. In patients with non-insulin dependent diabetes aortic elastic properties, evaluated by pressure-diameter relation, are imp aired. This could play an important part in the development of vascular com plications related to diabetes.