Prevalence of abnormal systemic hemodynamics in veterans with and without spinal cord injury

Abstract

Objective: Increased prevalence of heart rate and blood pressure abnormalities are evident in persons with spinal cord injury (SCI), but age, comorbid medical conditions, and prescription medication use may contribute. To determine differences in the prevalence of cardiac acceleration (heart rate ≥80 beats per minute), hypotension (blood pressure ≤110/70mmHg), orthostatic hypotension (OH) (-20/-10mmHg with upright positioning), and hypertension (HTN) (blood pressure ≥140/90mmHg) in veterans with and without SCI.

Design: Observational trial.

Setting: Medical center.

Participants: Subjects included veterans with SCI (n=62; cervical: tetraplegia, C3-8; high thoracic, T1-5; low thoracic, T7-L2) and veterans without SCI (n=160).

Interventions: None.

Main outcome measures: We assessed medical history, prescription medication use, and heart rate and blood pressure during a routine clinical visit. Prevalence rates of cardiac acceleration, hypotension, OH, and HTN were calculated using binary logistic regression analysis with 95% confidence intervals. The influence of SCI status, age, smoking status, cardiovascular diagnoses, and use of prescribed antihypertensive medications on the prevalence of abnormal heart rate and blood pressure recordings was determined.

Results: The diagnosis of HTN was reduced in the high thoracic and tetraplegia groups compared with the non-SCI and low thoracic groups. Use of antihypertensive medications was increased in the low thoracic group compared with the other 3 groups and was increased in the non-SCI group compared with the tetraplegia group. The prevalence of cardiac acceleration was reduced, and the prevalence of systolic hypotension was increased in the tetraplegia group. The prevalence of diastolic hypotension was increased in all SCI groups compared with the non-SCI group. For all analyses, increased prevalence of abnormal heart rate and blood pressure recordings was not further explained by the covariates, with the exception of age, cardiovascular diagnoses, and antihypertensive medications in the cardiac acceleration model; however, SCI status remained significant and was the dominant predictor variable.

Conclusions: Our data suggest that SCI status contributes to the prevalence of cardiac acceleration and systolic and diastolic hypotension regardless of cardiovascular medical conditions or prescription antihypertensive medication use.

Keywords: Hypertension; Hypotension; Orthostatic hypotension; Rehabilitation; Tachycardia.

Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

Box plot demonstrating the mean, max and min resting Heart Rate (HR: bpm) in the supine [A] and upright [B] positions among non-SCI veterans (open bar) and veterans with low thoracic (LT: dark gray bars), high thoracic (HT: hatched bars) and cervical lesions (T: light gray bars). * p<0.05; ** p<0.01; *** p<0.001 versus the Tetra group.

Figure 2

Box plot demonstrating the mean, max and min resting Systolic Blood Pressure (SBP: mmHg) in the supine [A] and upright [B] positions among non-SCI veterans (open bar) and veterans with low thoracic (LT: dark gray bars), high thoracic (HT: hatched bars) and cervical lesions (T: light gray bars). ** p<0.01; *** p<0.001 versus the Tetra group.

Figure 3

Box plot demonstrating the mean, max and min resting Diastolic Blood Pressure (DBP: mmHg) in the supine [A] and upright [B] positions among non-SCI veterans (open bar) and veterans with low thoracic (LT: dark gray bars), high thoracic (HT: hatched bars) and cervical lesions (T: light gray bars). *** p<0.001 versus the Tetra group; δ p<0.05 versus the non-SCI group.