Cardiovascular structure and function in baboons with Type 1 diabetes -- a transvenous ultrasound study

Diabetes mellitus is an important risk factor for both macrovascular and cardiac disease in humans. The availability of a novel intravenous ultrasound probe allows detailed interrogation of a large proportion of the vasculature, as well as the heart, during the same examination. Six male baboons (Papio hamadryas) with Type 1 diabetes and known microangiopathy, and six control animals were studied. Vascular structure in the major large arteries and cardiac function were studied using transvenous ultrasound introduced via the right femoral vein and positioned under fluoroscopy. All arteries were examined for atherosclerotic plaque and for presence of increased intima-media thickness (IMT). Left ventricular function was assessed at rest and following infusions of dobutamine (positive inotrope) and esmolol (negative inotrope). The procedure was performed safely and successfully in all cases. No atherosclerotic plaque was seen in either diabetic or normal baboons. There was no difference in the aortic IMT (0.38+/-0.04 vs. 0.37+/-0.05 mm, normal vs. diabetic, P=NS) or in doppler flow in the renal or iliac arteries between diabetic and normal baboons. Left ventricular wall thickness and systolic tissue velocity were similar in the two groups at rest (6.9+/-2.5 vs. 6.2+/-1.4 cm/s, normal vs. diabetic, P=NS), after dobutamine (15.5+/-2.2 vs. 12.7+/-3.9 cm/s, normal vs. diabetic, P=NS), and after esmolol (4.3+/-1.0 vs. 5.6+/-1.0 cm/s, normal vs. diabetic, P=NS). In a high primate model of diabetes with microangiopathy, the presence of hyperglycemia for 7 years per se does not produce abnormalities of macrovascular or cardiac structure.