Altered resting hemodynamics in lowerextremity arteries of individuals with spinal cord injury

Objective: To investigate lower-extremity arterial hemodynamics in individuals with spinal cord injury (SCI). We hypothesized that oscillatory shear index would be altered and resting mean shear would be higher in the lowerextremity arteries of SCI. Research: Cross-sectional study of men and women with SCIs compared to able-bodied controls. Subjects: Subjects included 105 ages 18-72 years with American Spinal Injury Association (ASIA) Impairment Scale grades A, B, or C and injury duration at least 5 years. Subjects were matched for age and cardiovascular disease risk factors with 156 able-bodied controls. Methods: Diameter and blood velocity were determined with subject at rest via ultrasound in superficial femoral, popliteal, brachial, and carotid arteries. Mean shear, antegrade shear, retrograde shear, and oscillatory shear index were calculated. Results: Oscillatory shear index was lower in SCI compared to controls for superficial femoral (0.16 ± 0.10 vs. 0.26 ± 0.06, P < 0.01) and popliteal arteries (0.20 ± 0.11 vs. 0.26 ± 0.05, P < 0.01). Mean shear rate was higher in SCI compared to controls for superficial femoral (43.54 ± 28.0 vs. 20.48 ± 13.1/second, P < 0.01) and popliteal arteries (30.43± 28.1 vs. 11.68 ± 9.5/second, P < 0.01). Conclusions: The altered resting hemodynamics in SCI are consistent with an atheroprotective hemodynamic environment.