Neuromuscular electric stimulation enhances endothelial vascular control and hemodynamic function in paretic upper extremities of patients with stroke.

Abstract

To investigate the effects of neuromuscular electric stimulation (NMES) on endothelial vascular control and hemodynamic function in patients in rehabilitation after acute stroke. Before-after trial. Inpatients in a tertiary hospital. Sixteen stroke patients (11 women, 5 men) with a mean age of 60.6+/-19.5 years. All patients received NMES for paretic wrist extensor and flexor muscles 30 minutes daily, 5 days a week, for 4 weeks. The nonparetic upper extremities, which served as controls, did not receive NMES. Laser Doppler perfusion testing was conducted to measure cutaneous microcirculatory responses to transdermal iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP), as specific endothelium-dependent and -independent vasodilators, respectively. Arterial and venous hemodynamic function was also measured by impedance plethysmography. Before NMES treatment, the venous capacity and compliance of the paretic extremities did not differ significantly from those of the nonparetic extremities. However, hyperemic arterial inflow, ACh-induced cutaneous perfusion, and the ratio of ACh- to SNP-induced cutaneous perfusion were lower in the paretic than in the nonparetic extremities. After NMES treatment, hyperemic arterial inflow and venous outflow increased by 21.5% and 57.2%, respectively, in the paretic extremities (P<.05). ACh-induced cutaneous perfusion and the ratio of ACh- to SNP-induced cutaneous perfusion were also significantly enhanced in the paretic extremities. In contrast, hyperemic arterial inflow decreased by 39.6% in the nonparetic extremities (P<.05), and endothelium-dependent cutaneous vasodilation also decreased significantly. NMES therapy may enhance the hyperemic arterial response and endothelium-dependent dilation in skin vasculature in the paretic upper extremities of patients with stroke.