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

Abstract

Type II (non-insulin-dependent) diabetes mellitus is associated with macrovascular disease. Therefore, we investigated the aortic elastic properties by a new method in patients with diabetes and control patients matched with them. Patients with Type II diabetes (n = 20) and control patients without diabetes (n = 21) were enrolled in the study. All patients had coronary artery disease. Instantaneous aortic diameter was measured by an intravascular catheter developed in our institution. Instantaneous aortic pressure was measured simultaneously at the same aortic level with a catheter-tip micromanometer. Thus, aortic pressure-diameter loops were obtained and slope and intercept were calculated. Aortic distensibility, stiffness constant and energy loss were also calculated. The mean age and the heart rate were similar in the two groups. The 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 cm2 x dyne(-1) x 10(-6), p <0.01); the slope was greater (113.4 +/- 120.1 vs 51.61 +/- 3.3 mmHg/mm, p < 0.01) and the intercept was less in diabetic patients (-2301.9 +/- 2692.9 vs -1114.45 +/- 295.6 mmHg, p < 0.01); the stiffness 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 between the groups. In patients with non-insulin dependent diabetes aortic elastic properties, evaluated by pressure-diameter relation, are impaired. This could play an important part in the development of vascular complications related to diabetes.