Orthostatic responses of blood pressure, renin and aldosterone in patients with spinal transections

Abstract

Orthosatic stimulations were performed with a tilt table on 32 patients paralyzed by neurologically complete transections of the spinal cord, of whom 10 had cervical cord lesions and 22 had thoracolumbar cord lesions. The hemodynamic and hormonal responses were compared between the 2 groups. In patients with cervical transections, a 43.1% reduction in systolic pressure, a 52.9% reduction in diastolic pressure and a 24.2% increase in heart rate were observed during head-up tilt. Eight (80%) of 10 cases had orthostatic hypotension. A 123.4% increase in plasma renin activity was also found. On the contrary, patients wth thoracolumbar transections showed significantly less reduction in systolic pressure (11%) and diastolic pressure (5.2%), lower frequency of orthostatic hypotension (13.6%) and less increase in plasma renin activity (43.8%) in response to head-up tilt. The findings suggest that the sympathetic nervous system regulating orthostatic blood pressure may be damaged while the renin-angiotensin system is activated in patients with transectional spinal cord lesions. The derangement is more severe in patients with cervical cord transections than those with thoracolumbar cord lesions.