Cardiac consequences of spinal cord injury: systematic review and meta-analysis

Abstract

ObjectiveConduct a meta-analysis to determine the impact of traumatic spinal cord injury (SCI) on echocardiographic measurements of left ventricular (LV) structure and function.MethodsMEDLINE and Embase were used for primary searches of studies reporting LV echocardiographic data in individuals with SCI. Of 378 unique citations, 36 relevant full-text articles were retrieved, and data from 27 studies were extracted for meta-analyses. Literature searches, article screening and data extraction were completed by two independent reviewers and compared for agreement. Primary analyses compared echocardiographic indices between individuals with SCI and able-bodied individuals, using a random effects model.ResultsData are reported as pooled effect estimates (95% CI). Data from 22 articles (474 participants) were included in the primary meta-analysis. Compared with able-bodied individuals, individuals with SCI had reductions to LV stroke volume of 11.8 mL (95% CI −17.8 to −5.9, p<0.001), end-diastolic volume of 19.6 mL (95% CI −27.2 to −11.9, p<0.001) and LV massindex of −7.7 g/m2 (95% CI −11.6 to −3.8, p<0.001), but ejection fraction was not different between the groups (95% CI −2.6% to 0.6%, p=0.236). Individuals with SCI also had altered indices of diastolic function, specifically a lowered ratio of early-to-late filling velocities (p=0.039), and augmented ratio of early diastolic flow-to-tissue velocities (p=0.021).ConclusionsIndividuals with SCI have smaller LV volumes and mass, and altered systolic and diastolic function. While this meta-analysis demonstrates important alterations to echocardiographic measures of cardiac structure and function at rest, future work should consider the impacts of SCI on the heart’s capacity or ‘reserve’ to respond to physiological challenges.PROSPERO registration numberCRD42017072333.

Respiratory muscle training in athletes with cervical spinal cord injury: effects on cardiopulmonary function and exercise capacity

“…In the present study, we observed similar percentage decreases with only a 45° head‐up tilt in individuals with cervical SCI, for whom LVEDV and LVSV are already reduced compared to able‐bodied individuals (Williams et al . ). Reduced LV volumes in response to tilt further highlight the challenges faced by athletes with cervical SCI with respect to mounting a normal cardiovascular response to exercise in the seated position.…”

Cardio-centric hemodynamic management improves spinal cord oxygenation and mitigates hemorrhage in acute spinal cord injury

“…Our present data extend these observations from the chronic setting by demonstrating that LV contractility is impaired immediately following high-level SCI. Importantly, we highlight that EF was unchanged despite clear reductions to LV contractility, reinforcing that EF does not adequately detect systolic or contractile dysfunction in SCI 11 . We have additionally identified a reduction to LV contractile reserve acutely after the injury, which may be attributable to a rapid loss of ‘baseline’ contractility and tonic neuro-hormonal activation of the myocardium that occurs following high-level SCI.…”

“…In experiment 1, the immediate reductions to key load-independent measures of LV systolic function incontrovertibly indicates that intrinsic contractile dysfunction in high-level SCI results from the immediate loss of descending sympathetic input following high-level injury. Previously, only a small collection of echocardiographic studies in humans had provided some evidence for chronically-altered LV systolic function in humans 11 , and the interpretation of those findings were limited due to the load-dependent nature of echo-derived data. To assess load-independent LV function our group has utilized LV pressure-volume catheterization in a chronic rodent model of SCI and reported reductions to LV E es after a T2 injury 12,13 .…”

“…Though both approaches effectively augmented MAP, this was achieved with DOB+ by increasing cardiac output, whereas NE predominantly increased vascular resistance and LV afterload (E a ) precluding any improvements to LV systolic output. This substantial arterial afterload is concerning as it may additionally stress or damage the myocardium if management is prolonged, and further exacerbate the long-term negative consequences of SCI on the heart 11 .…”

Respiratory muscle training in spinal cord injury: a breath of fresh air for the heart

“…Chronic haemodynamic ‘unloading’ of the heart following SCI causes substantial cardiac atrophy (Williams et al . ). As such, interventions that mitigate the harmful effects of this degeneration are crucial to help maintain exercise performance and offset cardiorespiratory dysfunction.…”