Increased pulse wave velocity in persons with spinal cord injury: the effect of the renin-angiotensin-aldosterone system

The Clinical Relevance of Autonomic Dysfunction, Cerebral Hemodynamics, and Sleep Interactions in Individuals Living With SCI

A myriad of physiological impairments is seen in individuals after a spinal cord injury (SCI). These include altered autonomic function, cerebral hemodynamics, and sleep. These physiological systems are interconnected and likely insidiously interact leading to secondary complications. These impairments negatively influence quality of life. A comprehensive review of these systems, and their interplay, may improve clinical treatment and the rehabilitation plan of individuals living with SCI. Thus, these physiological measures should receive more clinical consideration. This special communication introduces the under investigated autonomic dysfunction, cerebral hemodynamics, and sleep disorders in people with SCI to stakeholders involved in SCI rehabilitation. We also discuss the linkage between autonomic dysfunction, cerebral hemodynamics, and sleep disorders and some secondary outcomes are discussed. Recent evidence is synthesized to make clinical recommendations on the assessment and potential management of important autonomic, cerebral hemodynamics, and sleep-related dysfunction in people with SCI. Finally, a few recommendations for clinicians and researchers are provided.

Item Banks for Measuring the Effect of Blood Pressure Dysregulation on Health-Related Quality of Life in Persons With Spinal Cord Injury

OBJECTIVE

To report on the development and calibration of the new Blood Pressure Dysregulation Measurement System (BPD-MS) item banks that assess the effect of BPD on health-related quality of life (HRQOL) and the daily activities of Veterans and non-Veterans with spinal cord injury (SCI).

DESIGN

Cross-sectional survey study.

SETTING

Two Veteran Affairs medical centers and a SCI model system site.

PARTICIPANTS

454 respondents with SCI (n=262 American Veterans and n=192 non-Veterans; N=454).

INTERVENTIONS

Not applicable MAIN OUTCOME MEASURES: The BPD-MS item banks.

RESULTS

BPD item pools were developed and refined using literature reviews, qualitative data from focus groups, and cognitive debriefing of persons with SCI and professional caregivers. The item banks then underwent expert review, reading level assessment, and translatability review prior to field testing. The items pools consisted of 180 unique questions (items). Exploratory and confirmatory factor analyses, item response theory modeling, and differential item function investigations resulted in item banks that included a total of 150 items: 75 describing the effect of autonomic dysreflexia on HRQOL, 55 describing the effect of low blood pressure (LBP) on HRQOL, and 20 describing the effect of LBP on daily activities. In addition, 10-item short forms were constructed based on item response theory-derived item information values and the clinical relevance of item content.

CONCLUSIONS

The new BPD-MS item banks and corresponding 10-item short forms were developed using established rigorous measurement development standards, which represents the first BPD-specific patient-reported outcomes measurement system unique for use in the SCI population.

Altered heart rate variability and pulse-wave velocity after spinal cord injury

BACKGROUND

Heart rate variability (HRV) and pulse-wave velocity (PWV), indicators of cardiac function, are altered in patients with spinal cord injury (SCI), suggesting that autonomic cardiac function and arterial stiffness may underlie the high risk of cardiovascular complications in these patients. No study has simultaneously investigated HRV and PWV in the same patients.

AIM

To evaluate cardiovascular complications in SCI patients by comparing HRV and PWV between patients with and without SCI.

METHODS

In this cross-sectional pilot study, patients with (n = 60) and without SCI (n = 60) were recruited from December 7, 2019 to January 21, 2020. Each participant received a five-minute assessment of HRV and the cardiovascular system using the Medicore HRV Analyzer SA-3000P. Differences in HRV and PWV parameters between participants with and without SCI were statistically examined.

RESULTS

We observed a significant difference between participants with and without SCI with respect to the standard deviation of all normal-to-normal intervals, square root of the mean sum of squared successive risk ratio interval differences, physical stress index, total power, very-low frequency, low frequency, high frequency, and arterial elasticity.

CONCLUSION

Patients with SCI have weaker sympathetic and parasympathetic activity as well as lower arterial elasticity compared to those without, suggesting that SCI may increase cardiac function loading.