Influence of the neurological level of spinal cord injury on cardiovascular outcomes in humans: a meta-analysis

Background: Although motor and sensory deficits following spinal cord injury (SCI) are well known, there are still contrasting reports on how SCI affects baseline cardiovascular (CV) parameters and other autonomic functions. Study design: Meta-analysis is performed. Objectives: To examine the effect of injury level on supine and seated CV function in individuals with SCI. Methods: A total of 98 studies representing 1968 individuals were retrieved for analysis. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were abstracted from the studies and compared between four groups according to the neurological lesion level, cervical (C) SCI (C4-C8), high-thoracic (HT) SCI (T1-T6), low-thoracic lumbar (LTL) SCI (below T6) and able-bodied (AB) controls. Results: In the supine position, SBP, DBP and HR were lower in C compared with HT, LTL and AB (all P<0.04). In the seated position, SBP and DBP were significantly lower in C compared with LTL and AB (all P<0.003) and HR was significantly lower in C compared with LTL only (P-0.01). A final finding was that C exhibited a lower resting SBP in the seated compared with the supine position (P<0.001). Conclusion: Individuals with SCI exhibit a lesion-dependent impairment in resting CV function, whereby those with the highest injury had the greatest degree of CV dysfunction. A further finding was that individuals with a C injury exhibited a lower resting SBP in the seated vs supine position. Thus, clinicians and researchers should consider lesion level and body position when measuring and interpreting CV parameters in individuals with SCI. Spinal Cord (2012) 50, 484-492; doi: 10.1038/sc.2012.17; published online 6 March 2012