Cardiovascular Function After SCI
In addition to the loss of motor and sensory functioning, spinal cord injury (SCI), depending on the neurological level, may sever the descending sympathetic pathways that function in the control of the heart and arterial resistance within vessels, compromising blood pressure regulation [3;11-13;21]. On a daily basis, individuals with SCI face the challenge of managing their unstable blood pressure, which frequently results in persistent hypotension and/or episodes of uncontrolled hypertension[9;11;12;16;21]. Moreover, cardiovascular disorders in the acute and chronic stages of SCI are among the most common causes of death in individuals with SCI [6;12;17]. The lost of mobility and reduced activity levels accompanied by SCI contribute this increasing risk [7;12;18]. These cardiovascular conditions severely delay an individual’s participation in rehabilitation, extend hospital stay, limit the effectiveness of other treatments and interfere with daily life activities.
Low resting arterial blood pressure and orthostatic hypotension are common clinical problems in both acute and chronic SCI [2;4;8;12;14;15;21]. These conditions are thought to be related to the pooling of blood following increased plasma filtration in dependent regions of the body during upright posture leading to decreased venous return and reduced blood pressure[13;21]. Decreased or diminished sympathetic activity, the loss of lower extremity muscle function, impaired pulmonary function, increased venous compliance, decreased vascular dilation and impaired baroreflex regulation play major roles in these conditions after SCI [1;5;11;20;21]. Baseline low arterial blood pressure is commonly associated with increased fatigue, difficulties with concentration, and an inability to participate in activities of daily life. Symptoms related to orthostatic hypotension include fatigue or weakness, light-headedness, dizziness, blurred vision, dyspnea and restlessness [5;10;19].
1. Aslan SC, Randall DC, Donohue KD, Knapp CF, Patwardhan AR, McDowell SM, Taylor RF, Evans JM Blood pressure regulation in neurally intact human vs. acutely injured paraplegic and tetraplegic patients during passive tilt. Am J Physiol Regul Integr Comp Physiol 2007; 292:R1146-R1157 2. Aslan SC, Randall DC, Donohue KD, Knapp CF, Patwardhan AR, McDowell SM, Taylor RF, Evans JM Blood pressure regulation in neurally intact human vs. acutely injured paraplegic and tetraplegic patients during passive tilt. Am J Physiol Regul Integr Comp Physiol 2007; 292:R1146-R1157 3. Bravo G, Guizar-Sahagun G, Ibarra A, Centurion D, Villalon CM Cardiovascular alterations after spinal cord injury: an overview. Curr Med Chem Cardiovasc Hematol Agents 2004; 2:133-148 4. Claydon VE, Krassioukov AV Clinical correlates of frequency analyses of cardiovascular control after spinal cord injury. Am J Physiol Heart Circ Physiol 2008; 294:H668-H678 5. Claydon VE, Steeves JD, Krassioukov A Orthostatic hypotension following spinal cord injury: understanding clinical pathophysiology. Spinal Cord 2006; 44:341-351 6. DeVivo MJ, Krause JS, Lammertse DP Recent trends in mortality and causes of death among persons with spinal cord injury. Arch Phys Med Rehabil 1999; 80:1411-1419 7. Ditor DS, Macdonald MJ, Kamath MV, Bugaresti J, Adams M, McCartney N, Hicks AL The effects of body-weight supported treadmill training on cardiovascular regulation in individuals with motor-complete SCI. Spinal Cord 2005; 43:664-673 8. Figoni SF Cardiovascular and haemodynamic responses to tilting and to standing in tetraplegic patients: a review. para 1984; 22:99-109 9. Frankel HL, Mathias CJ The cardiovascular system in tetraplegia and paraplegia. In: Spinal cord trauma . Vinkin PJ, Bruyn GW, Klawans HL, Frankel HL (eds) Amsterdam ; New York, Elsevier; 1992 pp. 313-333. 10. Frisbie JH, Steele DJ Postural hypotension and abnormalities of salt and water metabolism in myelopathy patients. Spinal Cord 1997; 35:303-307 11. Garstang SV, Miller-Smith SA Autonomic nervous system dysfunction after spinal cord injury. Phys Med Rehabil Clin N Am 2007; 18:275-vii 12. Gondim FA, Lopes AC, Jr., Oliveira GR, Rodrigues CL, Leal PR, Santos AA, Rola FH Cardiovascular control after spinal cord injury. Curr Vasc Pharmacol 2004; 2:71-79 13. Krassioukov A, Claydon VE The clinical problems in cardiovascular control following spinal cord injury: an overview. Prog Brain Res 2006; 152:223-229 14. Mathias CJ Orthostatic hypotension: causes, mechanisms, and influencing factors. Neurology 1995; 45:S6-11 15. Mathias CJ, Frankel HL Autonomic disturbances in spinal cord lesions. Mathias CJ, Bannister R (eds) Oxford, Oxford University Press; 2002 pp. 494-513. 16. Myers J, Lee M, Kiratli J Cardiovascular disease in spinal cord injury: an overview of prevalence, risk, evaluation, and management. Am J Phys Med Rehabil 2007; 86:142-152 17. Myers J, Lee M, Kiratli J Cardiovascular disease in spinal cord injury: an overview of prevalence, risk, evaluation, and management. Am J Phys Med Rehabil 2007; 86:142-152 18. Myers J, Lee M, Kiratli J Cardiovascular disease in spinal cord injury: an overview of prevalence, risk, evaluation, and management. Am J Phys Med Rehabil 2007; 86:142-152 19. Sclater A, Alagiakrishnan K Orthostatic hypotension. A primary care primer for assessment and treatment. Geriatrics 2004; 59:22-27 20. Sidorov EV, Townson AF, Dvorak MF, Kwon BK, Steeves J, Krassioukov A Orthostatic hypotension in the first month following acute spinal cord injury. Spinal Cord 2008; 46:65- 21. Teasell RW, Arnold JM, Krassioukov A, Delaney GA Cardiovascular consequences of loss of supraspinal control of the sympathetic nervous system after spinal cord injury. Arch Phys Med Rehabil 2000; 81:506-516