Increased symptomatic autonomic dysfunction is associated with greater cardiovascular endothelial dysfunction following spinal cord injury.

BACKGROUND

Individuals with spinal cord injury (SCI) are known to have high rates of cardiovascular disease that have traditionally been attributed to inability to engage in adequate intensity exercise. However, individuals with SCI also commonly experience instability in blood pressure. Blood pressure fluctuations are known to contribute to cardiovascular disease in other conditions, though this relationship in SCI is unknown.

OBJECTIVE

To evaluate correlations between a clinical history of symptomatic blood pressure instability and objective evidence of vascular endothelial dysfunction in individuals with SCI.

DESIGN

Case control.

SETTING

Academic medical center.

PARTICIPANTS

Twenty-four individuals with SCI, 14 uninjured controls of matched age, gender, and body mass index.

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Symptomatic blood pressure instability was measured by the Autonomic Dysfunction Following SCI (ADFSCI) survey. Vascular endothelial dysfunction was quantified by ultrasound recordings of brachial flow mediated dilation following 5 minutes of forearm arterial occlusion.

RESULTS

Total ADFSCI scores were significantly higher in individuals with SCI compared to controls (41.0 vs. 9.0, p = .002). Both percentage of brachial flow mediated dilation and consensus recommended allometrically scaled percentage of flow mediated dilation were significantly less in individuals with SCI (p < .001 for both), demonstrating greater vascular dysfunction. More symptoms of blood pressure instability on the ADFSCI survey were correlated with more objective evidence of vascular dysfunction (R2 = 0.24, p = .03) for individuals with SCI. This relationship was not seen in uninjured controls.

CONCLUSIONS

In individuals with SCI, more severe symptoms of blood pressure instability are significantly correlated with more severe vascular endothelial dysfunction, making management of orthostatic hypotension and autonomic dysreflexia both high potential, modifiable risk factors for individuals with SCI to mitigate cardiovascular disease.