A Study of Forearm Blood Flow in Diabetics With and Without Autonomic Neuropathy

摘要

Abstract: Cardiovascular autonomic neuropathy (CAN), is a common but devastating complication of diabetes, resulting in an impairment of autonomic control of vascular tone and reactivity. The link between diabetic autonomic neuropathy and regional blood flow is poorly understood. In this report, we determined whether alterations in neural control of the vascular tone might contribute to forearm blood flow that responds to reactive hyperemia (maximal flow) and to rhythmic handgrip exercise at 45% of maximal voluntary contraction (submaximal flow) using venous occlusion plethysmography. Reactive and exercise hyperemias were measured in 57 type 2 diabetes patients (24 men, 33 women, age range 40-75 years) with (n=21) and without CAN (n=36). Autonomic function was assessed from five simple noninvasive cardiovascular reflex tests proposed by Ewing et al. Patients with CAN showed a significant higher maximal blood flow (P=0.001) and forearm vascular conductance (P=0.003) while forearm vascular resistance (P=0.012) was significantly lower. However, submaximal blood flow, forearm vascular conductance and vascular resistance in exercise hyperemic condition did not differ between the 2 groups. We conclude that increase maximal blood flow in patients with CAN may be related to impaired muscle autonomic nerve control of peripheral vascular resistance.