Cardiovascular dysfunction following spinal cord injury

Abstract

Cardiovascular issues following spinal cord injury (SCI) are of paramount importance considering they are the leading cause of death in this population. The disruption of autonomic pathways leads to a highly unstable cardiovascular system, with impaired blood pressure and heart rate regulation. In addition to low resting blood pressure, on a daily basis, the majority of those with SCI suffer from transient episodes of aberrantly low and high blood pressure (termed orthostatic hypotension and autonomic dysreflexia, respectively). In fact autonomic issues, including the resolution of autonomic dysreflexia, are frequently ranked by individuals with SCI to be of greater priority than regaining motor function. Due to a combination of these autonomic disturbances and a myriad of lifestyle factors, the pernicious process of cardiovascular disease is accelerated after SCI. Unfortunately, these secondary consequences of SCI are only beginning to receive appropriate clinical attention. Immediately after high-level SCI, major cardiovascular abnormalities present in the form of neurogenic shock. After subsiding, new issues related to blood pressure instability arise, including orthostatic hypotension and autonomic dysreflexia. The present chapter reviews autonomic control over the cardiovascular system before injury and the mechanisms underlying cardiovascular abnormalities after SCI, while also detailing the end- organ consequences including those of the heart, as well as the systemic and cerebral vasculature. The tertiary impact of cardiovascular dysfunction will also be discussed, such as the potential impediment of rehabilitation, impaired cognitive function, and limitations to exercise capacity. In the recent past, our understanding of autonomic dysfunction has been greatly enhanced; however, it is vital to further develop our understanding of the long-term consequences of these conditions, which give us insight to cardiovascular disease morbidity and mortality in this population.