Associations between arterial stiffness and blood pressure fluctuations after spinal cord injury.

STUDY

DESIGN

Cross-sectional.

OBJECTIVE

To examine the relationship between arterial stiffness and daily fluctuations in blood pressure (BP) owing to hypotensive events and autonomic dysreflexia (AD) in individuals with a T6 and above spinal cord injury (SCI).

SETTING

University-based laboratory in Vancouver, BC, Canada.

METHODS

Twenty-six individuals (73% male; 43 (11) years) with a chronic (> 1 year post SCI), traumatic, motor-complete SCI with a neurological level of injury of C4-T6 participated in this study. Arterial stiffness was assessed using carotid-to-femoral pulse wave velocity (cfPWV). BP was measured over a 24-hr period using ambulatory BP monitoring. AD was defined as an increase in systolic BP > 20 mmHg above baseline BP. Hypotensive events were defined as a decrease in systolic BP ≥ 20 mmHg and/or diastolic BP ≥ 10 mmHg below baseline. The severity and frequency of these events were quantified and Pearson and Spearman's correlations between them and cfPWV were performed.

RESULTS

AD severity and frequency were not were correlated with cfPWV. For hypotensive events, both the frequency (r = 0.412, P = 0.04) and severity (Δsystolic BP; r = -0.425, P = 0.03) of these events were correlated with cfPWV. The combined total of AD and hypotensive events (9 (5) events/day) was also correlated with cfPWV (r = 0.480, P = 0.01).

CONCLUSIONS

Hypotensive events, and the combined frequency of both hypo- and hypertensive events within a 24-hr period are associated with increased arterial stiffness in individuals with T6 and above SCI, suggesting BP instability may play a role in arterial stiffening post SCI.