Resting and Exercise Hyperemic Pulsatile Arterial Blood Flow in Insulin-dependent Diabetic Subjects

Pulsatile arterial blood flow was studied in 20 normal (N), 20 short-term (STIDDM; mean: 5.17 yr), and 20 long-term insulin-dependent diabetic patients (LTIDDM; mean: 14.76 yr) between the ages of 18 and 30 yr with no clinically detectable peripheral vascular disease. Measurements were taken from waveforms obtained noninvasively using an electromagnetic flowmeter at rest and immediately after a 3-min isometric exercise challenge of the right leg. At rest, both groups of diabetics exhibited minute flow values similar to those in the normal group. This was achieved, however, by increased vasodilation in peripheral tissues as indicated by a difference in waveform configuration. Diabetic subjects showed a significantly smaller peak flow, a less steep ascending and descending slope, and a higher minute heart rate than normal controls. After 3 min of isometric exercise, the diabetic groups exhibited significantly less minute flow, flow/pulse, and a more vasodilated flow pattern similar to that recorded at rest. In addition, the LTIDDM groupshowed significantly less arterial elasticity than N or STIDDM groups as indicated by a shorter propagation time. These findings imply that apparent functional changes in pulsatile arterial blood flow occur early in the time course of diabetes and are independent of duration.