Carotid Artery Stiffness and Aortic Augmentation Index in Physically Active Persons with Spinal Cord injury

Abstract

PURPOSE: Carotid artery stiffness and aortic augmentation index are associated with increased risk of cardiovascular disease and are inversely related to increased physical activity in able bodied populations. However, these benefits are not fully understood in person with spinal cord injury (SCI). Because regular exercise reduces cardiovascular risk in person with SCI, the purpose of this study was to compare the carotid artery stiffness and aortic augmentation index in person with SCI compared to non-disabled controls. METHODS: We used a cross-sectional study design to compare the arterial stiffness of 18 active wheelchair athletes with SCI and 13 aged-matched non-disabled controls (22.8 ± 3.2 vs 23.3 ± 3.6 yrs, P=0.67). The common carotid artery compliance and P stiffness index were measured using B-mode ultrasound with a high-resolution linear-array transducer. The arterial wave reflections were measured using applanation tonometry of the radial artery yielding data on aortic augmentation index. RESULTS: The carotid artery compliance (1.03 ± 0.36 vs 1.10 ± 0.55 mm2/kPa, P=0.17) and β stiffness index (4.66 ± 1.53 vs 5.66 ± 2.43, P=0.67) were not significantly different between the group with SCI compared with the non-disabled controls. Also, there were no group differences for aortic augmentation index (1.54 ± 11.2 vs 1.92 ± 12.6%, P=0.92). CONCLUSIONS: In conclusion, there were no differences in arterial function between active individuals with SCI and age matched non-disabled controls, suggesting regular exercise in persons with SCI preserved central and systemic arterial function. Our results suggest that regular exercise in persons with SCI is associated with a favorable effect on the arterial function in this population.