Hemodynamic effects of liquid food ingestion in mid-thoracic paraplegia: is supine postprandial hypotension related to thoracic spinal cord damage?

Treatment of postprandial hypotension with acarbose in an adult with cervical spinal cord injury: a case report

INTRODUCTION

Postprandial hypotension is a type of autonomic dysfunction where there is a decrease in systolic blood pressure of >20 mm HG within 2 h after eating thought to be due to poor cardiovascular compensation for splanchnic blood pooling that occurs with meals. This form of autonomic dysfunction is underdiagnosed in patients with spinal cord injury, likely in part because it can be asymptomatic.

CASE PRESENTATION

26-year-old with complete cervical spinal cord injury (SCI) presented with neck pain described as severe 10/10 pain, which felt like "a rope around his neck." Pain came on during and after meals and was associated with a feeling of pressure behind his eyes, white spots in his vision along with feeling as if he was going to pass out. The caregiver noted a systolic blood pressure drop by about 30-40 points with meals and lost weight due to avoiding eating. A diagnosis of post-prandial hypotension (PPH) was made and Acarbose was started at a low dose 25 mg three times per day with meals. During follow up, the patient reported complete resolution of drops of blood pressure, neck pain, and all associated symptoms. The patient was able to eat comfortably and gained weight.

DISCUSSION

There are few case reports on PPH in SCI and none looking at acarbose on a young, nondiabetic person with SCI. Clinicians should be aware that PPH can occur in young otherwise healthy people with SCI. Further research is needed on PPH, including the use of acarbose, in the SCI population.

Long-term prediction of functional independence using adjusted and unadjusted single items of the functional independence measure (FIM) at discharge from rehabilitation

CONTEXT

Being able to survive in the long-term independently is of concern to patients with spinal cord injury (SCI), their relatives, and to those providing or planning health care, especially at rehabilitation discharge. Most previous studies have attempted to predict functional dependency in activities of daily living within one year after injury.

OBJECTIVES

(1) build 18 different predictive models, each model using one FIM (Functional Independence Measure) item, assessed at discharge, as independent predictor of total FIM score at chronic phase (3-6 years post-injury) (2) build three different predictive models, using in each model an item from a different FIM domain with the highest predictive power obtained in objective (1) to predict "good" functional independence at chronic phase and (3) adjust the 3 models from objective (2) with known confounding factors.

METHODS

This observational study included 461 patients admitted to rehabilitation between 2009 and 2019. We applied regression models to predict total FIM score and "good" functional independence (FIM motor score ≥ 65) reporting adjusted R², odds ratios, ROC-AUC (95% CI) tested using 10-fold cross-validation.

RESULTS

The top three predictors, each from a different FIM domain, were Toilet (adjusted R² = 0.53, Transfers domain), Toileting (adjusted R² = 0.46, Self-care domain), and Bowel (adjusted R² = 0.35, Sphincter control domain). These three items were also predictors of "good" functional independence (AUC: 0.84-0.87) and their predictive power increased (AUC: 0.88-0.93) when adjusted by age, paraplegia, time since injury, and length of stay.

CONCLUSIONS

Discharge FIM items accurately predict long-term functional independence.

Postprandial Hypotension and Spinal Cord Injury

Postprandial hypotension (PPH) is defined as a fall of ≥20 mmHg in systolic blood pressure (SBP) or a SBP of <90 mmHg after having been >100 mmHg before the meal within two hours after a meal. The prevalence of PPH among persons with spinal cord injury (SCI) is unknown. Ambulatory blood pressure measurement was performed in 158 persons with SCI, 109 men, median age was 59.1 years (min.:13.2; max.: 86.2). In total, 78 persons (49.4%) had PPH after 114 out of 449 meals (25.4%). The median change in SBP during PPH was −28 mmHg (min.: −87; max.: −15 mmHg) and 96% of the PPH episodes were asymptomatic. The occurrence of PPH was correlated to older age (p = 0.001), level of injury (p = 0.023), and complete SCI (p = 0.000), but not, gender or time since injury. Further studies are needed to elucidate if PPH contributes to the increased cardiovascular mortality in the SCI population.

A case of postprandial hypotension in an individual with cervical spinal cord injury: treatment with acarbose

Introduction

Postprandial hypotension (PPH) is a postmeal drop in systolic blood pressure that may or may not be symptomatic. While the etiologies of PPH are incompletely understood, it is thought to occur when glucose absorption causes increased splanchnic blood flow or "pooling" in people who lack sufficient compensatory responses to support their systemic blood pressure. Postprandial hypotension is well described in individuals with neurodegenerative diseases, yet only rarely in people living with spinal cord injury (SCI). Acarbose is an alpha-glucosidase inhibitor that treats PPH by slowing gastric transit time and reducing glucose uptake in the small intestine, hence decreasing superior mesenteric artery blood flow.

Case presentation

A 62-year-old woman with long-standing cervical SCI presented with 5 years of worsening postprandial lightheadedness, visual "flashes", and neck pain. She had had multiple episodes of near and frank syncope and her prior medical team had initiated midodrine three times daily. We began treatment with acarbose, starting at 50 mg with each meal and rapidly titrating to 100 mg at mealtime. She noticed an immediate improvement in her symptoms and an attenuation of postmeal drops in both systolic and diastolic blood pressures.

Discussion

To our knowledge, this is one of the first described cases of PPH among people living with SCI. Given the autonomic dysfunction that frequently accompanies higher-level of injuries, it is possible that many more people with SCI have this condition, whether or not it is symptomatic. Acarbose is one of the several established treatments for PPH, and proved effective and tolerable for our patient.

The pathologic mechanisms underlying lumbar distraction spinal cord injury in rabbits

BACKGROUND CONTEXT

A reliable experimental rabbit model of distraction spinal cord injury (SCI) was established to successfully simulate gradable and replicable distraction SCI. However, further research is needed to elucidate the pathologic mechanisms underlying distraction SCI.

PURPOSE

The aim of this study was to investigate the pathologic mechanisms underlying lumbar distraction SCI in rabbits.

STUDY DESIGN

This is an animal laboratory study.

METHODS

Using a self-designed spine distractor, the experimental animals were divided into a control group and 10%, 20%, and 30% distraction groups. Pathologic changes to the spinal cord microvessels in the early stage of distraction SCI were identified by perfusion of the spinal cord vasculature with ink, production of transparent specimens, observation by light microscopy, and observation of corrosion casts of the spinal cord microvascular architecture by scanning electron microscopy. Malondialdehyde (MDA) and superoxide dismutase (SOD) concentrations in the injured spinal cord tissue were measured after 8 hours.

RESULTS

With an increasing degree and duration of distraction, the spinal cord microvessels were only partially filled and had the appearance of spasm until rupture and hemorrhage were observed. The MDA concentration increased and the SOD concentration decreased in the spinal cord tissue.

CONCLUSIONS

Changes to the internal and external spinal cord vessels led to spinal cord ischemia, which is a primary pathologic mechanism of distraction SCI. Lipid peroxidation mediated by free radicals took part in secondary pathologic damage of distraction SCI.

Improved Gait Speed After Robot-Assisted Gait Training in Patients With Motor Incomplete Spinal Cord Injury: A Preliminary Study

OBJECTIVE

To evaluate the clinical features that could serve as predictive factors for improvement in gait speed after robotic treatment.

METHODS

A total of 29 patients with motor incomplete spinal cord injury received 4-week robot-assisted gait training (RAGT) on the Lokomat (Hocoma AG, Volketswil, Switzerland) for 30 minutes, once a day, 5 times a week, for a total of 20 sessions. All subjects were evaluated for general characteristics, the 10-Meter Walk Test (10MWT), the Lower Extremity Motor Score (LEMS), the Functional Ambulatory Category (FAC), the Walking Index for Spinal Cord Injury version II (WISCI-II), the Berg Balance Scale (BBS), and the Spinal Cord Independence Measure version III (SCIM-III) every 0, and 4 weeks. After all the interventions, subjects were stratified using the 10MWT score at 4 weeks into improved group and non-improved group for statistical analysis.

RESULTS

The improved group had younger age and shorter disease duration than the non-improved group. All subjects with the American Spinal Injury Association Impairment Scale level C (AIS-C) tetraplegia belonged to the non-improved group, while most subjects with AIS-C paraplegia, AIS-D tetraplegia, and AIS-D paraplegia belonged to the improved group. The improved group showed greater baseline lower extremity strength, balance, and daily living function than the non-improved group.

CONCLUSION

Assessment of SCIM-III, BBS, and trunk control, in addition to LEMS, have potential for predicting the effects of robotic treatment in patients with motor incomplete spinal cord injury.

Participation and Life Satisfaction in Aged People with Spinal Cord Injury: Does Age at Onset Make a Difference?

BACKGROUND

Few studies have reported on outcomes in samples of elderly people with SCI and the impact of the age at onset of SCI is unclear.

OBJECTIVE

To study levels of participation and life satisfaction in individuals with SCI aged 65 years or older and to analyze differences in participation and life satisfaction scores between individuals injured before or after 50 years of age.

METHODS

This cross-sectional survey included 128 individuals with SCI who were at least 65 years old. Age at onset was dichotomized as <50 or ≥ 50 years of age. Participation was measured with the Frequency scale of the Utrecht Scale for Evaluation-Participation, and life satisfaction was measured with 5 items of the World Health Organization Quality of Life abbreviated form.

RESULTS

Participants who were injured before 50 years of age showed similar levels of functional status and numbers of secondary health conditions but higher participation and life satisfaction scores compared to participants injured at older age. In the multiple regression analysis of participation, lower current age, higher education, and having paraplegia were significant independent determinants of increased participation (explained variance, 25.7%). In the regression analysis of life satisfaction, lower age at onset and higher education were significant independent determinants of higher life satisfaction (explained variance, 15.3%).

CONCLUSIONS

Lower age at onset was associated with better participation and life satisfaction. This study did not reveal indications for worsening participation or life satisfaction due to an accelerated aging effect in this sample of persons with SCI.

Changes of functional outcomes according to the degree of completeness of spinal cord injury

OBJECTIVE

To evaluate whether an initial complete impairment of spinal cord injury (SCI) contributes to the functional outcome prediction, we analyzed the relationship between the degree of complete impairment according to the American Spinal Injury Association impairment scale (AIS), the posterior tibial nerve somatosensory evoked potential (PTSEP) and the changes of functional indices.

METHODS

Sixty subjects with SCI were studied who received rehabilitative management for over 2 months. The degree of completeness on basis of the initial AIS and PTSEP were evaluated at the beginning of rehabilitation. Following treatment, several functional indices, such as walking index for spinal cord injury version II (WISCI II), spinal cord independence measure version III (SCIM III), Berg Balance Scale (BBS), and Modified Barthel Index (MBI), were evaluated until the index score reached a plateau value.

RESULTS

The recovery efficiency of WISCI and BBS revealed a statistically significant difference between complete and incomplete impairments of initial AIS and PTSEP. The SCIM and MBI based analysis did not reveal any significant differences in terms of the degree of AIS and PTSEP completeness.

CONCLUSION

AIS and PTSEP were highly effective to evaluate the prognosis in post-acute phase SCI patients. BBS and WISCI might be better parameters than other functional indices for activities of daily living to predict the recovery of the walking ability in post-acute SCI.

Postprandial hypotension: a systematic review

BACKGROUND

Postprandial hypotension (PPH) is an important clinical problem, which has received inappropriately little attention.

METHODS

A systematic search of the databases PubMed, Embase, Cochrane Library, and Web of Knowledge, from their inception to the present time, was conducted to identify studies relevant to the epidemiology, pathophysiology, and/or management of PPH.

RESULTS

A total of 417 full-text papers were retrieved from database searching and, following screening, 248 were retained. Of these, 167 papers were considered eligible for inclusion.

CONCLUSIONS

PPH occurs commonly in older people and represents a major cause of morbidity. Although the pathophysiology of PPH remains poorly defined, diverse factors, including impairments in sympathetic and baroreflex function, release of vasodilatory peptides, the rate of small intestinal nutrient delivery, gastric distension, and splanchnic blood pooling, appear important. Current pharmacologic and nonpharmacologic management is suboptimal. Research into the pathophysiology of PPH represents a priority so that management can be targeted more effectively.

Regulation of cerebral blood flow after spinal cord injury

Significant cardiovascular and autonomic dysfunction occurs after era spinal cord injury (SCI). Two major conditions arising from autonomic dysfunction are orthostatic hypotension and autonomic dysreflexia (i.e., severe acute hypertension). Effective regulation of cerebral blood flow (CBF) is essential to offset these drastic changes in cerebral perfusion pressure. In the context of orthostatic hypotension and autonomic dysreflexia, the purpose of this review is to critically examine the mechanisms underlying effective CBF after an SCI and propose future avenues for research. Although only 16 studies have examined CBF control in those with high-level SCI (above the sixth thoracic spinal segment), it appears that CBF regulation is markedly altered in this population. Cerebrovascular function comprises three major mechanisms: (1) cerebral autoregulation, (i.e., ΔCBF/Δ blood pressure); (2) cerebrovascular reactivity to changes in PaCO2 (i.e. ΔCBF/arterial gas concentration); and (3) neurovascular coupling (i.e., ΔCBF/Δ metabolic demand). While static cerebral autoregulation appears to be well maintained in high-level SCI, dynamic cerebral autoregulation, cerebrovascular reactivity, and neurovascular coupling appear to be markedly altered. Several adverse complications after high-level SCI may mediate the changes in CBF regulation including: systemic endothelial dysfunction, sleep apnea, dyslipidemia, decentralization of sympathetic control, and dominant parasympathetic activity. Future studies are needed to describe whether altered CBF responses after SCI aid or impede orthostatic tolerance. Further, simultaneous evaluation of extracranial and intracranial CBF, combined with modern structural and functional imaging, would allow for a more comprehensive evaluation of CBF regulatory processes. We are only beginning to understand the functional effects of dysfunctional CBF regulation on brain function on persons with SCI, which are likely to include increased risk of transient ischemic attacks, stroke, and cognitive dysfunction.

Cardiovascular complications of spinal cord injury

BACKGROUND

The aim of this paper is to provide an overview of the autonomic innervation of the cardiovascular system and the cardiovascular sequelae of spinal cord injuries.

METHOD

A literature search was carried out in the PubMed database, with the search phrases "traumatic spinal cord injury"/"traumatic spinal cord injuries" together with "autonomic dysfunction", "autonomic dysreflexia" and "cardiovascular disease".

RESULTS

The most important cardiovascular complications in the acute phase are bradyarrhythmia, hypotension, enhanced vasovagal reflexes, supraventricular/ventricular ectopic beats, vasodilation and venous stasis. Important in the chronic phase are orthostatic hypotension and impaired regulation of blood pressure, blood volume and body temperature. Tetraplegia is frequently accompanied by autonomic dysreflexia, impaired transmission of cardial pain, loss of muscle mass in the left ventricle and pseudoinfarction. Patients with injuries above the sixth thoracic vertebra have a predisposition for autonomic dysreflexia. This is a condition characterised by sudden, uncontrolled sympathetic response accompanied by a rise in blood pressure. Autonomic dysreflexia usually leads to headaches and erythema on the upper chest. The condition may cause cerebral haemorrhage and is potentially life threatening. Patients with spinal cord injuries have an increased risk of atherosclerotic disease due to overweight, lipid disorders, metabolic syndrome and diabetes. They are predisposed to thrombotic emboli due to venous stasis and hypercoagulopathy, particularly immediately after the injury.

INTERPRETATION

Knowledge of cardiovascular sequelae after spinal cord injuries and assessment of these is important for correct diagnostics, planning of preventive measures and optimal treatment.

Insulin resistance in tetraplegia but not in mid-thoracic paraplegia: is the mid-thoracic spinal cord involved in glucose regulation?

STUDY DESIGN

Controlled experimental human study.

OBJECTIVES

To assess insulin resistance (IR) in tetraplegia and paraplegia, and the role of the spinal cord (SC) in glucose regulation.

SETTING

Laboratory of Spinal Research, Loewenstein Rehabilitation Hospital.

METHODS

Glucose and insulin levels and the heart rate variation spectral components LF (low frequency), HF (high frequency) and LF/HF were studied at supine rest, head-up tilt and after a standard meal in three groups: 13 healthy subjects, 7 patients with T(4)-T(6) paraplegia and 11 patients with C(4)-C(7) tetraplegia.

RESULTS

Glucose and insulin increased significantly after the meal in all groups (P<0.001). Glucose increased significantly more in the tetraplegia than in the other groups (P<0.01). Increases in insulin level tended to accompany increases in LF/HF after the meal in the tetraplegia and control groups but not in the paraplegia group.

CONCLUSION

Post-prandial IR appears in C(4)-C(7) but not in T(4)-T(6) SC injury. The results of the study, combined with previously published findings, are consistent with the hypotheses that IR is related to activation of the sympathetic nervous system, and that below T(4) the mid-thoracic SC is involved in the regulation of glucose and insulin levels.

Hemodynamic responses to head-up tilt after spinal cord injury support a role for the mid-thoracic spinal cord in cardiovascular regulation

BACKGROUND

Data showing a role for the mid-thoracic spinal cord (SC) in the control of hemodynamic changes is scarce despite existing evidence for its involvement in autonomic regulation.

STUDY DESIGN

On the basis of the open label prospective series comparing three groups.

OBJECTIVE

To determine whether the mid-thoracic SC has a role in hemodynamic regulation during head-up tilt (HUT).

SETTING

Spinal Research Laboratory, Loewenstein Rehabilitation Hospital.

METHODS

A total of 13 healthy control subjects, 10 patients with T(4)-T(6) paraplegia and 11 with C(4)-C(7) tetraplegia were examined during supine rest and during HUT. Heart rate (HR), blood pressure (BP), HR spectral components (lower frequency fluctuation (LF), higher frequency fluctuations (HF) and LF/HF) and cerebral blood flow velocity (CBFV) were continuously measured or calculated.

RESULTS

BP response to HUT differed among these groups (P<0.02). During HUT, BP decreased markedly in the tetraplegia group (from a mean value of 81.65 to 67.69  mm Hg), and increased in the control groups (from 92.89 to 95.44 mm Hg) and in the T(4)-T(6) paraplegia group (from 96.24 to 97.86 mm Hg). Significant correlation was found in the control and tetraplegia groups between increases in HR LF/HF and HR at HUT (r>0.7; P<0.01). No such correlation was found in the paraplegia group. HUT effect on HR and CBFV was significant in all groups (P<0.001), but group differences were statistically non-significant.

CONCLUSION

Findings were generally compatible with those of comparable previously published studies, but they also support a role for the mid-thoracic SC in hemodynamic regulation, which should be considered in clinical setting and in research.

Cerebrovascular reactivity and dynamic autoregulation in tetraplegia

Humans with spinal cord injury have impaired cardiovascular function proportional to the level and completeness of the lesion. The effect on cerebrovascular function is unclear, especially for high-level lesions. The purpose of this study was to evaluate the integrity of dynamic cerebral autoregulation (CA) and the cerebrovascular reactivity in chronic tetraplegia (Tetra). After baseline, steady-state hypercapnia (5% CO(2)) and hypocapnia (controlled hyperventilation) were used to assess cerebrovascular reactivity in 6 men with Tetra (C5-C7 lesion) and 14 men without [able-bodied (AB)]. Middle cerebral artery blood flow velocity (MCAv), cerebral oxygenation, arterial blood pressure (BP), heart rate (HR), cardiac output (Q; model flow), partial pressure of end-tidal CO(2) (Pet(CO(2))), and plasma catecholamines were measured. Dynamic CA was assessed by transfer function analysis of spontaneous fluctuations in BP and MCAv. MCAv pulsatility index (MCAv PI) was calculated as (MCAv(systolic) - MCAv(diastolic))/MCAv(mean) and standardized by dividing by mean arterial pressure (MAP). Resting BP, total peripheral resistance, and catecholamines were lower in Tetra (P < 0.05), and standardized MCAv PI was approximately 36% higher in Tetra (P = 0.003). Resting MCAv, cerebral oxygenation, HR, and Pet(CO(2)) were similar between groups (P > 0.05). Although phase and transfer function gain relationships in dynamic CA were maintained with Tetra (P > 0.05), coherence in the very low-frequency range (0.02-0.07 Hz) was approximately 21% lower in Tetra (P = 0.006). Full (hypo- and hypercapnic) cerebrovascular reactivity to CO(2) was unchanged with Tetra (P > 0.05). During hypercapnia, standardized MCAv PI reactivity was enhanced by approximately 78% in Tetra (P = 0.016). Despite impaired cardiovascular function, chronic Tetra involves subtle changes in dynamic CA and cerebrovascular reactivity to CO(2). Changes are evident in coherence at baseline and MCAv PI during baseline and hypercapnic states in chronic Tetra, which may be indicative of cerebrovascular adaptation.

Cold pressor test in tetraplegia and paraplegia suggests an independent role of the thoracic spinal cord in the hemodynamic responses to cold

BACKGROUND

Cold application to the hand (CAH) is associated in healthy people with increase in heart rate (HR) and blood pressure (BP).

OBJECTIVE

To study hemodynamic responses to CAH in humans following spinal cord injuries of various levels, and examine the effect of spinal cord integrity on the cold pressor response.

DESIGN

An experimental controlled study.

SETTING

The spinal research laboratory, Loewenstein Hospital, Raanana, Israel.

SUBJECTS

Thirteen healthy subjects, 10 patients with traumatic T(4-6) paraplegia and 11 patients with traumatic C(4-7) tetraplegia.

MAIN OUTCOME MEASURES

HR, BP, HR and BP spectral components (low frequency, LF; high frequency, HF; LF/HF), cerebral blood flow velocity (CBFV) and cerebrovascular resistance index (CVRi).

METHODS

The outcome measures of the three subject groups monitored for HR, BP and CBFV were compared from 5 min before to 5 min after 40-150 s of CAH. The recorded signals were digitized online and analyzed offline in both the time and frequency domains.

RESULTS

During CAH, HR and CVRi increased significantly in all subject groups (P<0.001), and BP in control subjects and in the tetraplegia group (P<0.01). BP increase was not statistically significant in paraplegia, and CBFV, HR LF, HR HF and BP LF did not change significantly during CAH in any group.

CONCLUSIONS

The CAH effect in tetraplegia and the suppressed BP increase in paraplegia, supported by the other findings, suggest a contribution of an independent thoracic spinal mechanism to the cold pressor response.