Objectives
To investigate the prevalence of autonomic dysreflexia (AD), orthostatic hypotension (OH) and circadian changes in blood pressure after spinal cord injury (SCI).
Methods
Eighty-five patients diagnosed with SCI were enrolled. 24-hour ambulatory blood pressure monitoring (ABPM) was utilized to assess AD. Using ABPM, systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were measured at 30-minute intervals at day-time and 60-minute interval at night-time. AD was defined as SBP 20 mmHg higher than basal SBP. OH was evaluated using head up tilt test (HUTT). OH was defined as a decrease in SBP of ≥20 mmHg or a decrease in DBP of ≥10 mmHg after 3 minutes in the 60° angle of tilt test.
Results
The study included 60 men and 25 women with a mean age of 57.8±13.5 years. Regarding the cause of SCI, 64 and 21 patients had SCI due to trauma and non-trauma, respectively. Mean duration after SCI was 29.0 ± 64.3 months. Regarding the level of injury, 47 patients had cervical SCI and 28 patients had thoracic SCI and 10 patients had lumbar SCI. With respect to SCI severity, 18 patients were classified as having motor complete SCI (AIS grades A and B) and 67 patients were classified as having motor incomplete SCI (AIS grades C and D).
According to the ABPM, AD occurred in 41 patients (48%) and OH occurred in 29 patients (76%). In subacute and motor complete group, the night-time mean SBP appeared to be 2.6mmHg, 3.9mmHg higher than day-time mean SBP, respectively. These findings show reverse-dipper BP pattern, suggesting the loss of nocturnal dipping in SCI patients (Table 1). There was also a significant increase in OH prevalence in subacute and motor complete group compared to chronic and motor incomplete group (Table 2).
When comparing the result according to the injury level, average day-time and night-time SBP were 121.1±16.2 mmHg and 124.8±18.1 mmHg, in above T6 group. And the night-time mean SBP appeared to be 3.7mmHg higher than day-time mean SBP, suggesting the loss of nocturnal BP dipping. However, this phenomenon did not appear in the below T6 group (Table 3). In above T6 group, AD and OH prevalence were significantly higher than below T6 group (Table 2). In the below T6 group, 24hr mean SBP was 126.7±11.7 mmHg, which was higher than the above T6 group (121.8±16.1) (Table 3).
Conclusions
AD and OH were highly prevalent in SCI patient, especially in above T6 level. In addition, there was the loss of nocturnal BP dipping in SCI patients. These results suggest the necessity of proper diagnostic and therapeutic interventions for managing AD and OH.
|
