Suppressed cutaneous endothelial vascular control and hemodynamic changes in paretic extremities with edema in the extremities of patients with hemiplegia

Objective: To investigate peripheral circulatory function and its underlying mechanisms in the paretic upper extremity after a stroke. Design: Case-control study. Setting: A department of physical medicine and rehabilitation in Taiwan. Participants: A total of 53 hemiplegic patients (28 men, 25 women; mean age ± standard deviation; 58.2±3.8y) were studied. Subjects were divided into edema and nonedema groups. The edema group included 29 hemiplegic patients with edematous paretic upper extremities. Twenty-four hemiplegic patients in the nonedema group did not suffer from limb edema in the paretic upper extremity. Interventions: Not applicable. Main Outcome Measures: Cutaneous microvascular perfusion responses to 3 grade levels of iontophoretically applied 1% acetylcholine (ACh), 1% ACh plus 1% N^G-monomethyl-L-arginine (L-NMMA), and 1% sodium nitroprusside (SNP) in the skin of subjects’ forearms were determined by laser Doppler perfusion measurements. Moreover, hemodynamic characteristics in the arterial and venous vessels were measured by impedance plethysmography. Results: Resting arterial inflow and venous capacity, tone, and outflow in paretic extremities did not significantly differ from nonparetic extremities, but the hyperemic arterial inflow was lower in paretic extremities than in nonparetic extremities, and paretic extremities were associated with lower ACh- and ACh plus L-NMMA-induced cutaneous perfusions than non-paretic extremities. ACh-induced cutaneous perfusions also decreased much more significantly in edematous paretic extremities than in nonedematous paretic extremities, and skin vascular responses to SNP do not differ significantly between paretic and nonparetic extremities. Conclusion: Cutaneous microcirculatory function in the paretic upper extremity after stroke may be impaired. The impairment may occur because of decreased endothelium-dependent dilation in skin vasculature. Dysfunction in cutaneous microcirculation tends to be more pronounced in the edematous than in the nonedematous extremities.