Altered blood pressure reactivity in adolescent diabetics

We examined hemodynamic responses to a variety of physiologic stimuli in 14 normotensive adolescents with type I diabetes and 45 healthy controls to determine whether structural vascular changes contribute to a reduced vasodilator capacity in adolescent diabetics. We asked, in adolescents with type I diabetes: (1) Are structural vascular changes present? (2) Are changes in the systemic vascular bed reflected in abnormal blood pressure regulation? and (3) Is abnormal vascular reactivity associated with either diabetes duration or control? Diabetic subjects were outpatients treated at the Medical College of Virginia, ages 13 to 18 years. Diabetes duration averaged 7.5 years. Each subject underwent an echocardiogram, dynamic and isometric exercise testing, and forearm plethysmography. Compared to controls, diabetic subjects had (1) higher systolic and diastolic blood pressure during dynamic and handgrip exercise, (2) decreased forearm vasodilator capacity in response to ischemia, and (3) an increased aortic peak velocity. Group diastolic filling abnormalities were found, but these did not persist after adjustment for heart rate. The following variables were related to both diabetes duration and control (average glycosylated hemoglobin): (1) diastolic blood pressure during dynamic exercise, (2) resting forearm vascular resistance, and (3) forearm vascular reactivity. In addition, diabetes duration correlated with isometric exercise diastolic blood pressure, and diabetes control correlated with resting diastolic blood pressure. In young diabetics we found that (1) abnormalities of the resistance vessels of the forearm may be present, (2) the degree of vascular change is related to diabetes duration and control, and (3) aortic distensibility may be impaired.