Neurogenic orthostatic hypotension: pathophysiology, evaluation, and management

Norepinephrine Reuptake Inhibition, an Emergent Treatment for Neurogenic Orthostatic Hypotension

The NET (norepinephrine transporter) is situated in the prejunctional plasma membrane of noradrenergic neurons. It is responsible for >90% of the norepinephrine uptake that is released in the autonomic neuroeffector junction. Inhibitors of this cell membrane transporter, known as norepinephrine reuptake inhibitors (NRIs), are commercially available for the treatment of depression and attention deficit hyperactivity disorder. These agents increase norepinephrine levels, potentiating its action in preganglionic and postganglionic adrenergic neurons, the latter through activation of α-1 adrenoreceptors. Previous studies found that patients with neurogenic orthostatic hypotension can improve standing blood pressure and reduce symptoms of neurogenic orthostatic hypotension after a single administration of the selective NRI atomoxetine. This effect was primarily observed in patients with impaired central autonomic pathways with otherwise normal postganglionic sympathetic fibers, known as multiple system atrophy. Likewise, patients with normal or high norepinephrine levels may benefit from NRIs. The long-term efficacy of NRIs for the treatment of neurogenic orthostatic hypotension-related symptoms is currently under investigation. In summary, an in-depth understanding of the pathophysiology of neurogenic orthostatic hypotension resulted in the discovery of a new therapeutic pathway targeted by NRI.

Blood pressure variability at rest and during pressor challenges in patients with acute ischemic stroke

INTRODUCTION

Patients with acute ischemic stroke (AIS) have elevated blood pressure (BP) variability (BPV) and reduced baroreflex sensitivity (BRS) at rest for several days after initial stroke symptoms. We aimed to assess BPV and BRS in AIS patients during pressor challenge maneuvers in the acute and subacute phases of stroke. Pressor challenge maneuvers simulate day-to-day activities and can predict the quality of life.

METHODS

Continuous beat-to-beat BP and ECG in 15 AIS patients (mean age 69 ± 7.5 years) and 15 healthy controls (57 ± 16 years) were recorded at rest and during a 5-min rapid head positioning (RHP) paradigm. Patients were assessed within 24 h (acute phase) and 7 days (subacute phase) of stroke onset. Low frequency (LF) SBP power (measure of BPV), LF-α, and combined α-index (measure of BRS) were calculated from the recordings.

RESULTS

In the acute phase, at rest, LF-SBP power was higher (P = 0.024) and α-index was lower (P = 0.006) in AIS patients than in healthy controls. There was no change in LF-SBP during RHP in the patients but in healthy controls, it increased significantly (P = 0.018). In the subacute phase, at rest, the alpha-index increased (P = 0.037) and LF-SBP decreased (P = 0.029) significantly in the AIS patients, however, there was still no rise in the LF-SBP power during RHP (P = 0.240).

CONCLUSION

AIS patients have a high resting BPV. High resting BPV may be responsible for blunted BPV responses during pressor challenge maneuvers such as RHP, suggesting ongoing autonomic dysfunction and compromised quality of life.

Serum 25-Hydroxyvitamin D Level Is Positively Associated with Vascular Reactivity Index in Patients with Type 2 Diabetes Mellitus

Circulating 25-hydroxyvitamin D (25(OH)D) significantly influences endothelial function. This study assessed the correlation between serum 25(OH)D and endothelial function using the vascular reactivity index (VRI) in patients with type 2 diabetes mellitus (T2DM). Fasting blood samples from 102 T2DM participants and VRI were assessed. Patients were divided into three categories based on VRI: low (VRI < 1.0), intermediate (1.0 ≤ VRI < 2.0), and good (VRI ≥ 2.0). Among these patients, 30 (29.4%) had poor, 39 (38.2%) had intermediate, and 33 (32.4%) exhibited good vascular reactivity. Higher serum fasting glucose (p = 0.019), glycated hemoglobin (p = 0.009), and urinary albumin-to-creatinine ratio (p = 0.006) were associated, while lower prevalence of hypertension (p = 0.029), lower systolic blood pressure (p = 0.027), lower diastolic blood pressure (p < 0.001), and lower circulation 25(OH)D levels (p < 0.001) were associated with poor vascular reactivity. Significant independent associations between diastolic blood pressure (p = 0.002) and serum 25(OH)D level (p < 0.001) and VRI were seen in T2DM patients according to multivariable forward stepwise linear regression analysis. Serum 25(OH)D positively correlated with VRI values, and lower levels of serum 25(OH)D were linked to endothelial dysfunction in T2DM patients.

A retrospective analysis of neurogenic orthostatic hypotension in long-term care facility residents with recurrent falls

INTRODUCTION

Approximately 50 % of residents in long-term care facilities fall yearly and orthostatic hypotension accounts for a significant portion of them. Neurogenic orthostatic hypotension - a subtype of orthostatic hypotension - is important to be recognized as its management is far more complex; undertreatment of these older adults can lead to recurrent falls, high healthcare cost burden, and increased morbidity and mortality. The primary purpose of our study was to describe the rate of neurogenic orthostatic hypotension in older adults in a long-term care facility, with a secondary purpose to describe risk factors for neurogenic orthostatic hypotension in this population.

METHODS

We conducted a retrospective case-control study of residents with recurrent falls at the Dayton Veteran's Affairs long-term care facility. Charts were manually reviewed. Inclusion criterion was three or more falls and age 65 or greater; we did not have exclusion criteria. ICD10 codes and most recent primary care physician notes were used to identify comorbidity diagnoses. Recent orthostatic vitals were used to assess orthostatic hypotension or neurogenic orthostatic hypotension diagnoses.

RESULTS

Of our sample of 224 residents, we observed a prevalence of 20.5 % for neurogenic orthostatic hypotension and 32.1 % for orthostatic hypotension. Neither of them had diagnosis of neurogenic orthostatic hypotension documented. Parkinson's disease was associated with neurogenic orthostatic hypotension (OR-4.3; p = 0.002). Hypertension was prevalent in 69.6 % of residents with orthostatic vitals suggestive of neurogenic orthostatic hypotension.

CONCLUSION

Older adults with recurrent falls at a long-term care facility meet criteria for neurogenic orthostatic hypotension diagnosis far more often than is documented. Common comorbidities associated with neurogenic orthostatic hypotension in this population include Parkinson's disease.

The Role of Muscle Strength in the Sit-to-Stand Task in Parkinson's Disease

Background

Rising from a chair or the sit-to-stand (STS) task is frequently impaired in individuals with Parkinson's disease (PD). These patients commonly attribute such difficulties to weakness in the lower extremities. However, the role of muscle strength in the STS transfer task has not been fully elucidated.

Objective

We aim at determining the role of muscle strength in the STS task.

Methods

We studied 90 consecutive patients with PD and 52 sex- and age-matched controls. Lower limb strength was determined in both legs by clinical examination using the Medical Research Council Scale, dynamometric (leg flexion) and weighting machine (leg pressure) measures. Patients were interrogated regarding the presence of subjective lower limb weakness or allied sensations.

Results

There were 20 patients (22.2%) with abnormal STS task (item 3.9 of the MDS-UPDRS-III ≥2 points). These patients had higher modified Hoehn and Yahr stage (P  <  0.001) and higher total motor scores of the MDS-UPDRS(P  <  0.001), compared with 70 PD patients with normal STS task. Patients with abnormal STS task endorsed lower limb weakness more frequently and had lower muscle strength in the proximal lower extremities, compared to PD patients with normal STS task and normal controls. The presence of perceived lower limb weakness increased the risk of an abnormal STS task, OR: 11.93 (95% C.I. 1.51-94.32), whereas a hip extension strength ≤9 kg/pressure also increased the risk of abnormal STS task, OR: 4.45 (95% C.I. 1.49-13.23). In the multivariate regression analysis, bradykinesia and decreased hip strength were related to abnormal STS task.

Conclusions

Patients with PD and abnormal STS task complain more commonly of lower limb weakness and have decreased proximal lower limb strength compared to patients with PD and normal STS task, likely contributing to abnormalities in performing the STS task.

Serum sclerostin level is positively associated with endothelial dysfunction measured by digital thermal monitoring in patients with type 2 diabetes: A prospective cross-sectional study

Sclerostin and dickkopf-1 (DKK1), extracellular inhibitors of the canonical Wnt/β-catenin signaling pathway, have been associated with vascular aging and atherosclerosis. This study aimed to assess the correlation of sclerostin and DKK1 concentrations with endothelial function measured using vascular reactivity index (VRI) in patients with type 2 diabetes mellitus (T2DM). Fasting blood samples were collected from 100 patients with T2DM. Endothelial function and VRI were measured using digital thermal monitoring and circulating sclerostin and DKK1 levels by enzyme-linked immunosorbent assays. VRI values < 1.0, 1.0-1.9, and > 2.0 indicated poor, intermediate, and good vascular reactivity, respectively. Overall, 30, 38, and 32 patients had poor, intermediate, and good vascular reactivity, respectively. Older age, higher serum glycated hemoglobulin, urinary albumin-to-creatinine ratio, and sclerostin as well as lower hypertension prevalence, systolic blood pressure, and diastolic blood pressure (DBP) were associated with poor VRI. Multivariable forward stepwise linear regression analysis showed that DBP (β = 0.294, adjusted R2 change = 0.098, P < .001), log-glycated hemoglobin (β = -0.235, adjusted R2 change = 0.050, P = .002), log-urine albumin-to-creatinine ratio (β = -0.342, adjusted R2 change = 0.227, P < .001), and log-sclerostin level (β = -0.327, adjusted R2 change = 0.101, P < .001) were independently associated with VRI. Serum sclerostin, along with glycated hemoglobin and albumin-to-creatinine ratio, exhibited a negative correlation with VRI, while DBP showed a positive correlation with VRI. These factors can independently predict endothelial dysfunction in patients with T2DM.

Refractory Hypotension in a Late-Onset Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like Episodes (MELAS) Male with m.3243 A>G Mutation: A Case Report

(1) Introduction: Symptom spectrum can be of great diversity and heterogeneity in mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) patients in clinical practice. Here, we report a case of MELAS presenting asymptomatic refractory hypotension with m.3243 A>G mutation. (2) Case representation: A 51-year-old male patient presented with a headache, vertigo, and difficulty in expression and understanding. The magnetic resonance imaging of the brain revealed an acute stroke-like lesion involving the left temporoparietal lobe. A definitive diagnosis of MELAS was given after the genetic test identified the chrM-3243 A>G mutation. The patient suffered recurrent stroke-like episodes in the 1-year follow-up. Notably, refractory hypotension was observed during hospitalizations, and no significant improvement in blood pressure was found after continuous use of vasopressor drugs and fluid infusion therapy. (3) Conclusions: We report a case of refractory hypotension which was unresponsive to fluid infusion therapy found in a patient with MELAS. Our case suggests that comprehensive management should be paid attention to during treatment. A further study on the pathological mechanism of the multisystem symptoms in MELAS would be beneficial to the treatment of patients.

Evaluation of Autonomic Nervous System Dysfunction in Childhood Obesity and Prader-Willi Syndrome

The autonomic nervous system (ANS) may play a role in the distribution of body fat and the development of obesity and its complications. Features of individuals with Prader-Willi syndrome (PWS) impacted by PWS molecular genetic classes suggest alterations in ANS function; however, these have been rarely studied and presented with conflicting results. The aim of this study was to investigate if the ANS function is altered in PWS. In this case-control study, we assessed ANS function in 20 subjects with PWS (6 males/14 females; median age 10.5 years) and 27 body mass index (BMI) z-score-matched controls (19 males/8 females; median age 12.8 years). Standardized non-invasive measures of cardiac baroreflex function, heart rate, blood pressure, heart rate variability, quantitative sudomotor axon reflex tests, and a symptom questionnaire were completed. The increase in heart rate in response to head-up tilt testing was blunted (p < 0.01) in PWS compared to controls. Besides a lower heart rate ratio with Valsalva in PWS (p < 0.01), no significant differences were observed in other measures of cardiac function or sweat production. Findings suggest possible altered sympathetic function in PWS.

Graves' Disease Combined With Orthostatic Hypotension: A Two-Case Report

Graves' disease (GD) is the most common cause of hyperthyroidism in the clinic, accounting for about 85% of all hyperthyroidisms. However, hyperthyroidism combined with OH has been rarely reported in the international community. We analyzed the clinical characteristics and pathogenesis of GD combined with orthostatic hypotension. We conducted a retrospective analysis of 2 GD combined with orthostatic hypotension cases diagnosed by Chinese and Western Medical Association Hospital of Southern Medical University from July to August 2018 and discussed their clinical characteristics, treatment methods, and pathogenesis. The main clinical manifestations of both two patients with hyperthyroidism were vertigo during postural changes or activities and relief from supine position and blood volume supplementation. Considering the lack of blood volume, the symptoms were alleviated after symptomatic treatment. The possibility of hyperthyroidism combined with orthostatic hypotension should be taken into consideration in clinical diagnosis and treatment.

Investigating the possible mechanisms of autonomic dysfunction post-COVID-19

Patients with long COVID suffer from many neurological manifestations that persist for 3 months following infection by SARS-CoV-2. Autonomic dysfunction (AD) or dysautonomia is one complication of long COVID that causes patients to experience fatigue, dizziness, syncope, dyspnea, orthostatic intolerance, nausea, vomiting, and heart palpitations. The pathophysiology behind AD onset post-COVID is largely unknown. As such, this review aims to highlight the potential mechanisms by which AD occurs in patients with long COVID. The first proposed mechanism includes the direct invasion of the hypothalamus or the medulla by SARS-CoV-2. Entry to these autonomic centers may occur through the neuronal or hematogenous routes. However, evidence so far indicates that neurological manifestations such as AD are caused indirectly. Another mechanism is autoimmunity whereby autoantibodies against different receptors and glycoproteins expressed on cellular membranes are produced. Additionally, persistent inflammation and hypoxia can work separately or together to promote sympathetic overactivation in a bidirectional interaction. Renin-angiotensin system imbalance can also drive AD in long COVID through the downregulation of relevant receptors and formation of autoantibodies. Understanding the pathophysiology of AD post-COVID-19 may help provide early diagnosis and better therapy for patients.

Controls of Central and Peripheral Blood Pressure and Hemorrhagic/Hypovolemic Shock

The pressure exerted on the heart and blood vessels because of blood flow is considered an essential parameter for cardiovascular function. It determines sufficient blood perfusion, and transportation of nutrition, oxygen, and other essential factors to every organ. Pressure in the primary arteries near the heart and the brain is known as central blood pressure (CBP), while that in the peripheral arteries is known as peripheral blood pressure (PBP). Usually, CBP and PBP are correlated; however, various types of shocks and cardiovascular disorders interfere with their regulation and differently affect the blood flow in vital and accessory organs. Therefore, understanding blood pressure in normal and disease conditions is essential for managing shock-related cardiovascular implications and improving treatment outcomes. In this review, we have described the control systems (neural, hormonal, osmotic, and cellular) of blood pressure and their regulation in hemorrhagic/hypovolemic shock using centhaquine (Lyfaquin^®) as a resuscitative agent.

Objective and self-perceived lower limb weakness in Parkinson's disease

BACKGROUND

Lower limb weakness is a long-recognized symptom in patients with Parkinson's disease (PD), described by James Parkinson in his seminal report on 'paralysis agitans'. However, little is known on the frequency, clinical correlations, and association with objective decrease in muscle strength in such patients.

OBJECTIVE

The objective of this study was to assess the frequency of objective and perceived lower limb weakness in patients with PD.

METHODS

We studied 90 consecutive patients with PD and 52 age-matched controls. We recorded clinical and demographic variables, as well as perceived weakness and allied abnormal lower limb sensations, including 'heavy legs', 'fatigued legs', and 'pain'. Symptoms consistent with restless legs syndrome were not considered. Lower limb strength was determined in both legs by means of the Medical Research Council scale, dynamometric (leg flexion) and weighting machine (leg pressure) measures.

RESULTS

Weakness and allied abnormal lower limb sensations were reported in 69% of patients with PD and 21% of healthy controls. Patients with PD had decreased leg pressure compared with healthy controls (p = 0.002). Among patients with PD, an association between perceived leg weakness (and allied sensations) and gait freezing (p = 0.001) was observed in the multivariate regression analysis; however, these variables only explained 30.4% of the variance. Moreover, PD patients with and without abnormal lower limb sensations had similar muscle strength by objective measurements.

CONCLUSION

Perceived lower limb weakness and allied abnormal sensations are common in patients with PD. However, there is a dissociation between perceived weakness and objective muscle strength in the lower limbs. These abnormal sensations were mostly related to gait freezing but a causal association is questionable.

Autonomic dysfunction in non-critically ill COVID-19 patients during the acute phase of disease: an observational, cross-sectional study

Introduction

Evidence is emerging about an extra-pulmonary involvement of SARS-CoV-2, including the nervous system. Autonomic dysfunction in patients recovering from acute coronavirus disease 2019 (COVID-19) has been recently described. Dysautonomic symptoms have been reported in the acute phase of the disease, but clear evidence is lacking, especially in the non-critical forms of the infection.

Objective

The aim of this study is to assess the prevalence of dysautonomia in acute, non-critically ill COVID-19 patients.

Methods

In this observational, cross-sectional study, we compared 38 non-critically ill patients with acute COVID-19 (COVID + group) to 38 healthy volunteers (COVID − group) in order to assess the prevalence of signs and symptoms of dysautonomia through the administration of the composite autonomic symptom score 31 (COMPASS-31) and an active standing test. Comparisons between groups were performed by means of both univariate and multivariate analyses.

Results

The prevalence of orthostatic hypotension was significantly higher in the COVID + group. Higher total scores of COMPASS-31 were observed in the COVID + group than controls. Significant differences between groups emerged in the secretomotor, orthostatic intolerance, and gastrointestinal COMPASS-31 domains. All these results maintained the statistical significance after the adjustment for concomitant drugs with a known effect on the autonomic nervous system assumed by the study participants, except for the differences in the gastrointestinal domain of COMPASS-31.

Conclusion

Our results suggest that an autonomic dysfunction could be an early manifestation of COVID-19, even in the contest of mild forms of the infection.

Cardiovascular/Stroke Risk Stratification in Parkinson's Disease Patients Using Atherosclerosis Pathway and Artificial Intelligence Paradigm: A Systematic Review

Parkinson’s disease (PD) is a severe, incurable, and costly condition leading to heart failure. The link between PD and cardiovascular disease (CVD) is not available, leading to controversies and poor prognosis. Artificial Intelligence (AI) has already shown promise for CVD/stroke risk stratification. However, due to a lack of sample size, comorbidity, insufficient validation, clinical examination, and a lack of big data configuration, there have been no well-explained bias-free AI investigations to establish the CVD/Stroke risk stratification in the PD framework. The study has two objectives: (i) to establish a solid link between PD and CVD/stroke; and (ii) to use the AI paradigm to examine a well-defined CVD/stroke risk stratification in the PD framework. The PRISMA search strategy selected 223 studies for CVD/stroke risk, of which 54 and 44 studies were related to the link between PD-CVD, and PD-stroke, respectively, 59 studies for joint PD-CVD-Stroke framework, and 66 studies were only for the early PD diagnosis without CVD/stroke link. Sequential biological links were used for establishing the hypothesis. For AI design, PD risk factors as covariates along with CVD/stroke as the gold standard were used for predicting the CVD/stroke risk. The most fundamental cause of CVD/stroke damage due to PD is cardiac autonomic dysfunction due to neurodegeneration that leads to heart failure and its edema, and this validated our hypothesis. Finally, we present the novel AI solutions for CVD/stroke risk prediction in the PD framework. The study also recommends strategies for removing the bias in AI for CVD/stroke risk prediction using the PD framework.

A Novel Methodology for the Synchronous Collection and Multimodal Visualization of Continuous Neurocardiovascular and Neuromuscular Physiological Data in Adults with Long COVID

Background: Reports suggest that adults with post-COVID-19 syndrome or long COVID may be affected by orthostatic intolerance syndromes, with autonomic nervous system dysfunction as a possible causal factor of neurocardiovascular instability (NCVI). Long COVID can also manifest as prolonged fatigue, which may be linked to neuromuscular function impairment (NMFI). The current clinical assessment for NCVI monitors neurocardiovascular performance upon the application of orthostatic stressors such as an active (i.e., self-induced) stand or a passive (tilt table) standing test. Lower limb muscle contractions may be important in orthostatic recovery via the skeletal muscle pump. In this study, adults with long COVID were assessed with a protocol that, in addition to the standard NCVI tests, incorporated simultaneous lower limb muscle monitoring for NMFI assessment. Methods: To conduct such an investigation, a wide range of continuous non-invasive biomedical sensing technologies were employed, including digital artery photoplethysmography for the extraction of cardiovascular signals, near-infrared spectroscopy for the extraction of regional tissue oxygenation in brain and muscle, and electromyography for assessment of timed muscle contractions in the lower limbs. Results: With the proposed methodology described and exemplified in this paper, we were able to collect relevant physiological data for the assessment of neurocardiovascular and neuromuscular functioning. We were also able to integrate signals from a variety of instruments in a synchronized fashion and visualize the interactions between different physiological signals during the combined NCVI/NMFI assessment. Multiple counts of evidence were collected, which can capture the dynamics between skeletal muscle contractions and neurocardiovascular responses. Conclusions: The proposed methodology can offer an overview of the functioning of the neurocardiovascular and neuromuscular systems in a combined NCVI/NMFI setup and is capable of conducting comparative studies with signals from multiple participants at any given time in the assessment. This could help clinicians and researchers generate and test hypotheses based on the multimodal inspection of raw data in long COVID and other cohorts.

Autism Spectrum Disorder in Children Is Not Associated With Abnormal Autonomic Nervous System Function: Hypothesis and Theory

The quest to understand the pathophysiology of autism spectrum disorder (ASD) has led to extensive literature that purports to provide evidence for autonomic dysfunction based on heart rate and heart rate variability (HRV), in particular respiratory sinus arrhythmia (RSA), a measure of parasympathetic functioning. Many studies conclude that autism is associated with vagal withdrawal and sympathetic hyperactivation based on HRV and electrodermal analyses. We will argue that a critical analysis of the data leads to the hypothesis that autonomic nervous system dysfunction is not a dominant feature of autism. Most children with ASD have normal parasympathetic baseline values and normal autonomic responses to social stimuli. The existing HRV and electrodermal data cannot lead to the conclusion of an over-excitation of the sympathetic nervous system. A small subgroup of ASD children in experimental settings has relatively low RSA values and relatively high heart rates. The data suggest that this is likely associated with a relatively high level of anxiety during study conditions, associated with co-morbidities such as constipation, or due to the use of psychoactive medication. Many studies interpret their data to conform with a preferred hypothesis of autonomic dysfunction as a trait of autism, related to the polyvagal theory, but the HRV evidence is to the contrary. HRV analysis may identify children with ASD having autonomic dysfunction due to co-morbidities.

Unexplained falls in the elderly

Falls are a geriatric syndrome affecting mortality, morbidity, and institutionalization. Falls are also the leading cause of unintentional injury and a common emergency department presentation. Physical and psychological issues may develop after falling, leading to increase in dependency and disability and their relative costs. The pathogenesis of falls is multi-factorial, being indeed the result of the interaction between increased individual susceptibility, high risk activities and environmental hazards. The patient should be evaluated for gait, standing balance, mobility, muscle weakness, cognitive status, osteoporosis risk, sensorial impairment, urinary incontinence, functional status, and for possible residential environmental hazards. It is also mandatory to obtain a full report of the circumstances and a careful therapeutic recognition. However not all falls are explainable. Indeed, retrograde amnesia and the frequent absence of a witness complicate history collection of falls in older adults. In this case, "the management of unexplained falls should be the same as that for unexplained syncope" as stated by the latest version of the European Society of Cardiology guidelines on syncope. In this context, the investigation of the cardiovascular autonomic nervous system and the use of implantable loop recorder have an increasing role. The present paper addresses the diagnostic approach to falls in older adults through a comprehensive multifactorial risk assessment and examines evidence and gaps on fall prevention strategies.

Autonomic dysfunction in post-COVID patients with and witfhout neurological symptoms: a prospective multidomain observational study

The autonomic nervous system (ANS) can be affected by COVID-19, and dysautonomia may be a possible complication in post-COVID individuals. Orthostatic hypotension (OH) and postural tachycardia syndrome (POTS) have been suggested to be common after SARS-CoV-2 infection, but other components of ANS function may be also impaired. The Composite Autonomic Symptom Scale 31 (COMPASS-31) questionnaire is a simple and validated tool to assess dysautonomic symptoms. The aim of the present study was to administer the COMPASS-31 questionnaire to a sample of post-COVID patients with and without neurological complaints. Participants were recruited among the post-COVID ambulatory services for follow-up evaluation between 4 weeks and 9 months from COVID-19 symptoms onset. Participants were asked to complete the COMPASS-31 questionnaire referring to the period after COVID-19 disease. Heart rate and blood pressure were manually taken during an active stand test for OH and POTS diagnosis. One-hundred and eighty participants were included in the analysis (70.6% females, 51 ± 13 years), and OH was found in 13.8% of the subjects. Median COMPASS-31 score was 17.6 (6.9-31.4), with the most affected domains being orthostatic intolerance, sudomotor, gastrointestinal and pupillomotor dysfunction. A higher COMPASS-31 score was found in those with neurological symptoms (p < 0.01), due to more severe orthostatic intolerance symptoms (p < 0.01), although gastrointestinal (p < 0.01), urinary (p < 0.01), and pupillomotor (p < 0.01) domains were more represented in the non-neurological symptoms group. This study confirms the importance of monitoring ANS symptoms as a possible complication of COVID-19 disease that may persist in the post-acute period.

Cardiology meets neurology: clinical presentation and management of patients with primary neurogenic disorders and orthostatic intolerance

Patients with primary neurogenic disorders such as pure autonomic failure or multiple system atrophy may initially present with cardiocirculatory symptoms such as orthostatic intolerance or fluctuations in heart rate with symptomatic tachycardia. It is therefore clinically important to identify such patients since circulatory manifestations are only one of a series of symptoms resulting from autonomic dysfunction in various organ systems. These patients require a multimodal diagnostic and therapeutic approach and should undergo extensive evaluation in a specialized autonomic nervous system (ANS) outpatient unit. Based on a clinical case presentation, the current review summarizes the diagnostic and therapeutic approach to key cardiovascular symptoms of primary autonomic disorders and their neurological work-up in a specialized autonomic function laboratory.

Pharmacokinetics and pharmacodynamics of ampreloxetine, a novel, selective norepinephrine reuptake inhibitor, in symptomatic neurogenic orthostatic hypotension

Purpose

Ampreloxetine is a novel, selective, long-acting norepinephrine reuptake (NET) inhibitor being investigated as a once-daily oral treatment for symptomatic neurogenic orthostatic hypotension (nOH) in patients with autonomic synucleinopathies. The purpose of this study was to characterize the pharmacokinetic and pharmacodynamic profiles of ampreloxetine in this target population.

Methods

Patients with nOH were enrolled in a multicenter, phase II clinical trial of ampreloxetine (NCT02705755). They received escalating doses over 5 days in the clinical research unit, followed by 20 weeks of open-label treatment and then a 4-week withdrawal. As neurochemical biomarkers of NET inhibition, we assayed plasma concentrations of norepinephrine (NE) and its main intraneuronal metabolite 3,4-dihydroxyphenylglycol (DHPG) pre- and post-ampreloxetine.

Results

Thirty-four patients with nOH were enrolled. Plasma ampreloxetine concentrations increased with repeated escalating doses, with peak concentrations observed 6–9 h post-drug administration. The median ampreloxetine dose in the 20-week treatment phase was 10 mg once daily. Plasma ampreloxetine concentrations reached steady state by 2 weeks, with stable plasma levels over 24 h. No influence of age or renal function on ampreloxetine plasma concentrations was observed. On treatment, compared to baseline, plasma NE significantly increased by 71% (p < 0.005), plasma DHPG significantly declined by 22% (p < 0.05), and the NE:DHPG ratio significantly increased (p < 0.001).

Conclusions

Persistent elevation of plasma NE levels accompanied by reduced DHPG levels after ampreloxetine suggests reduced neuronal reuptake and metabolism of NE in postganglionic efferent sympathetic neurons. The findings are consistent with long-lasting NET inhibition, which may increase vasoconstrictor tone, supporting once-daily ampreloxetine dosing in patients with nOH.

Management Strategies for Comorbid Supine Hypertension in Patients with Neurogenic Orthostatic Hypotension

PURPOSE OF REVIEW

In autonomic failure, neurogenic orthostatic hypotension (nOH) and neurogenic supine hypertension (nSH) are interrelated conditions characterized by postural blood pressure (BP) dysregulation. nOH results in a sustained BP drop upon standing, which can lead to symptoms that include lightheadedness, orthostatic dizziness, presyncope, and syncope. nSH is characterized by elevated BP when supine and, although often asymptomatic, may increase long-term cardiovascular and cerebrovascular risk. This article reviews the pathophysiology and clinical characteristics of nOH and nSH, and describes the management of patients with both nOH and nSH.

RECENT FINDINGS

Pressor medications required to treat the symptoms of nOH also increase the risk of nSH. Because nOH and nSH are hemodynamically opposed, therapies to treat one condition may exacerbate the other. The management of patients with nOH who also have nSH can be challenging and requires an individualized approach to balance the short- and long-term risks associated with these conditions. Approaches to manage neurogenic BP dysregulation include nonpharmacologic approaches and pharmacologic treatments. A stepwise treatment approach is presented to help guide neurologists in managing patients with both nOH and nSH.

Orthostatic Hypertension and Hypotension and Outcomes in CKD: The CRIC (Chronic Renal Insufficiency Cohort) Study

Rationale & Objective

There are limited data about the prevalence and prognostic significance of orthostatic hypo- and hypertension in patients with chronic kidney disease. The objective of this study is to determine the prevalence of orthostatic hypo- and hypertension in a cohort of patients with chronic kidney disease and examine their association with clinical outcomes.

Study Design

Prospective cohort study: Chronic Renal Insufficiency Cohort (CRIC) Study.

Setting & Population

7 clinical centers, participants with chronic kidney disease.

Exposures

Orthostatic hypotension (decline in systolic blood pressure [BP] > 20 mm Hg) and orthostatic hypertension (increase in systolic BP > 20 mm Hg) from seated to standing position.

Outcomes

Cardiovascular and kidney outcomes and mortality.

Analytical Approach

Logistic regression was used to determine factors associated with orthostatic hypo- and hypertension; Cox regression was used to examine associations with clinical outcomes.

Results

Mean age of study population (n = 3,873) was 58.1 ± 11.0 years. There was a wide distribution of change in systolic BP from seated to standing (from −73.3 to +60.0 mm Hg); 180 participants (4.6%) had orthostatic hypotension and 81 (2.1%) had orthostatic hypertension. Diabetes, reduced body mass index, and β-blocker use were independently associated with orthostatic hypotension. Black race and higher body mass index were independently associated with orthostatic hypertension. After a median follow-up of 7.9 years, orthostatic hypotension was independently associated with high risk for cardiovascular (HR, 1.12; 95% CI, 1.03-1.21) but not kidney outcomes or mortality. Orthostatic hypertension was independently associated with high risk for kidney (HR, 1.51; 96% CI, 1.14-1.97) but not cardiovascular outcomes or mortality.

Limitations

Orthostatic change in BP was ascertained at a single visit.

Conclusions

Orthostatic hypotension was independently associated with higher risk for cardiovascular outcomes, whereas orthostatic hypertension was associated with higher risk for kidney outcomes. These findings highlight the importance of orthostatic BP measurement in practice and the need for future investigation to understand the mechanisms and potential interventions to minimize the risk associated with orthostatic changes in BP.

Clinical and neurohormonal characteristics in African Americans with neurogenic orthostatic hypotension

PURPOSE

Neurogenic orthostatic hypotension (nOH) is the hallmark of neurodegenerative forms of autonomic failure, including pure autonomic failure, multiple system atrophy, and Parkinson's disease. Studies have shown autonomic physiological differences in Africans Americans (AA) such as lower heart rate variability, enhanced blood pressure reactivity, and blunted sympathetic neural response compared to non-Hispanic whites. However, the clinical characteristics and neurohormonal profile of autonomic failure in AA is unknown.

METHODS

A total of 65 patients with nOH participated in this study (9 AA and 56 non-Hispanic whites). Both groups were of similar age and comorbidity status, and they underwent standardized autonomic testing and assessment of neurohormonal levels and renin activity and aldosterone in supine and upright positions.

RESULTS

There were no significant differences in baseline autonomic clinical characteristics between non-Hispanic whites and AA with nOH. Non-Hispanic whites demonstrated a significant increase in upright renin activity compared to AA (295 ± 88% vs. 13 ± 13%, respectively). AA showed a blunted increase in aldosterone compared to non-Hispanic whites (188 ± 27% vs. 59 ± 38%, respectively). These results indicated persistent suppression of the renin-angiotensin system in AA, particularly during upright posture.

CONCLUSION

Our findings demonstrate that AA with nOH have similar clinical characteristics and hemodynamic autonomic profiles, but lower upright renin activity and aldosterone levels, compared to non-Hispanic whites. Renin suppression persists in AA with severe autonomic failure and can potentially contribute to postural changes and supine hypertension.

Resting Heart Rate Variability Is Associated With Subsequent Orthostatic Hypotension: Comparison Between Healthy Older People and Patients With Rapid Eye Movement Sleep Behavior Disorder

Background: Orthostatic hypotension (OH) caused by autonomic dysfunction is a common symptom in older people and patients with idiopathic rapid eye movement sleep behavior disorder (iRBD). The orthostatic challenge test is a standard autonomic function test that measures a decrease of blood pressure during a postural change from supine to standing positions. Although previous studies have reported that changes in heart rate variability (HRV) are associated with autonomic dysfunction, no study has investigated the relationship between HRV before standing and the occurrence of OH in an orthostatic challenge test. This study aims to examine the connection between HRV in the supine position and the occurrence of OH in an orthostatic challenge test. Methods: We measured the electrocardiograms of patients with iRBD and healthy older people during an orthostatic challenge test, in which the supine and standing positions were held for 15 min, respectively. The subjects were divided into three groups: healthy controls (HC), OH-negative iRBD [OH (-) iRBD], and OH-positive iRBD [OH (+) iRBD]. HRV measured in the supine position during the test were calculated by time-domain analysis and Poincaré plots to evaluate the autonomic dysfunction. Results: Forty-two HC, 12 OH (-) iRBD, and nine OH (+) iRBD subjects were included. HRV indices in the OH (-) and the OH (+) iRBD groups were significantly smaller than those in the HC group. The multivariate logistic regression analysis for OH identification for the iRBD groups showed the model whose inputs were the HRV indices, i.e., standard deviation 2 (SD2) and the percentage of adjacent intervals that varied by more than 50 ms (pNN50), had a receiver operating characteristic curve with area under the curve of 0.840, the sensitivity to OH (+) of 1.000, and the specificity to OH (-) of 0.583 (p = 0.023). Conclusions: This study showed the possibility that short-term HRV indices in the supine position would predict subsequent OH in iRBD patients. Our results are of clinical importance in terms of showing the possibility that OH can be predicted using only HRV in the supine position without an orthostatic challenge test, which would improve the efficiency and safety of testing.

Cardiovascular Disorders Mediated by Autonomic Nervous System Dysfunction

Cardiovascular disorders, such as orthostatic hypotension and supine hypertension, are common in patients with neurodegenerative synucleinopathies such as Parkinson disease (PD), and may also occur in other conditions, such as peripheral neuropathies, that result in autonomic nervous system (ANS) dysfunction. Dysfunction and degeneration of the ANS are implicated in the development of orthostatic and postprandial hypotension and impaired thermoregulation. Neurogenic orthostatic hypotension (nOH) results from sympathetic failure and is a common autonomic disorder in PD. Supine hypertension may also occur as a result of both sympathetic and parasympathetic dysfunction in conjunction with nOH in the majority of patients with PD. Management of supine hypertension in the setting of nOH can be counterintuitive and challenging. Additionally, the presence of other noncardiovascular comorbidities, such as diabetes mellitus and peripheral edema, may further contribute to the burden of disease. ANS dysfunction thus presents major healthcare implications and challenges for neurology and cardiovascular practices, necessitating an integrated neurology and cardiology management approach.

Pharmacokinetics of Ampreloxetine, a Norepinephrine Reuptake Inhibitor, in Healthy Subjects and Adults with Attention-Deficit/Hyperactive Disorder or Fibromyalgia Pain

Background and Objective

Ampreloxetine is a novel norepinephrine reuptake inhibitor in development for the treatment of symptomatic neurogenic orthostatic hypotension. The objectives of this analysis were to define the pharmacokinetics of once-daily oral ampreloxetine and provide dose recommendations for clinical development.

Methods

We fitted a population pharmacokinetic model to ampreloxetine plasma concentrations from single- and multiple-ascending dose trials in healthy subjects and two phase II studies in adult subjects with attention-deficit/hyperactive disorder or fibromyalgia at doses of 2–50 mg.

Results

Ampreloxetine pharmacokinetics was best described by a two-compartment model with first-order absorption and elimination. The terminal half-life was 30–40 h, resulting in sustained drug concentrations for the entire 24-h dosing interval at steady state. Covariates of age, weight, or renal impairment did not impact ampreloxetine exposure. Cytochrome P450 2D6 phenotype had no influence on ampreloxetine exposure. Sex and smoking status were identified as statistically significant covariates, suggesting a role for cytochrome P450 1A2 in the elimination of ampreloxetine. Despite statistical significance, differences in ampreloxetine exposure in male vs female subjects and smokers vs non-smokers were not clinically meaningful at the recommended dose. At the 10-mg dose, > 75% norepinephrine transporter inhibition and < 50% serotonin transporter inhibition are anticipated for adult subjects.

Conclusions

The population pharmacokinetic model effectively described the plasma concentration–time profile of ampreloxetine after single and multiple doses. Population pharmacokinetic/pharmacodynamic analysis justified using a fixed dosing regimen with no dose adjustments across a broad population and can be used to inform dosing strategies in future clinical studies.

Clinical Trial Registration

ClinicalTrials.gov identifier numbers NCT01693692 (fibromyalgia); NCT01458340 (attention-deficit/hyperactive disorder).

Electronic supplementary material

The online version of this article (10.1007/s40262-020-00918-7) contains supplementary material, which is available to authorized users.

Diminished Dynamic Physical Performance Is Associated With Orthostatic Hypotension in Geriatric Outpatients

BACKGROUND AND PURPOSE

Orthostatic hypotension (OH), a blood pressure drop after postural change, is a highly prevalent and disabling syndrome in older adults. Yet, the association between physical performance and OH is not clearly established. The aim of this study was to determine whether different types of physical performance are associated with OH in a clinically relevant population of geriatric outpatients.

METHODS

This cross-sectional study included 280 geriatric outpatients (mean age: 82.2 years, standard deviation: 7.1). Orthostatic hypotension was determined using intermittently measured blood pressure and continuously measured blood pressure in a random subgroup of 58 patients. Physical performance was classified into a dynamic type (4-m Walk Test, Chair Stand Test, and Timed Up and Go test) and a static type (standing balance tests, handgrip strength). Associations were analyzed using logistic regression models with adjustments for age, sex, weight, and height.

RESULTS

Diminished physical performance on the Chair Stand Test was associated with OH measured intermittently. Diminished physical performance on all dynamic physical domains (4-m Walk Test, Chair Stand Test, and Timed Up and Go test) was associated with OH measured continuously. Static physical performance was not significantly associated with OH.

CONCLUSION

Dynamic physical performance tests with a substantial postural change and center of mass displacement were significantly associated with OH. The influence of physical performance on OH in daily routine activities should be further explored to establish counteracting interventions.

[Autonomic dysfunction in the patient with neurodegenerative disease]

Autonomic dysfunction is a common condition in the alpha-synucleinopathies (Parkinson's disease, dementia with Lewy bodies, multiple system atrophy). Cardiovascular symptoms may include orthostatic hypotension, supine hypertension or decreased heart rate response. A clinical suspicion and physical examination are essential for diagnosis, taking blood pressure in supine and standing positions. The electrocardiogram may show a prolongation of the PR and QT intervals, while 24-hour ambulatory blood pressure monitoring provides information on blood pressure patterns. Cardiac sympathetic dysfunction can be confirmed by an innervation myocardial scintigraphy with ¹²³-I-methylbenzylguanidine (¹²³-I-MIBG). This can reflect specific neuronal noradrenergic uptake. We present the case of a man with Parkinson's disease who was diagnosed with cardiovascular autonomic dysfunction after a complete study.

Persistent unexplained chest pain and dyspnea in a patient with coronary artery disease: a case report

Background

Neurogenic orthostatic hypotension, a sustained decrease in blood pressure upon standing, is caused by autonomic nervous system failure and characterized by an insufficient increase in heart rate needed to maintain blood pressure upon standing. In this case, neurogenic orthostatic hypotension symptoms preceded a diagnosis of Parkinson disease. A diagnosis of underlying neurogenic orthostatic hypotension significantly changed the course of treatment for this patient.

Case presentation

An 84-year-old woman was referred to a cardiologist by her primary care practitioner for evaluation of exertional dyspnea and chest pain upon walking a few feet. Her medical history included hypertension, hypothyroidism, and osteoarthritis. Based on her continued symptoms, the patient underwent 2 cardiac catheterizations for coronary artery stenosis. After the catheterizations, exertional dyspnea and chest pain continued, and subsequently, dysphagia to solid foods and episodic dizziness developed. Orthostatic evaluation showed a supine blood pressure of 150/80 mmHg with a heart rate of 70 beats per min. Upon standing for 3 min, the patient’s blood pressure decreased to 110/74 mmHg with a heart rate of 76 beats per min. The diagnostic criteria for orthostatic hypotension were met, and the lack of an adequate compensatory heart rate increase upon standing was consistent with a neurogenic cause (ie, neurogenic orthostatic hypotension), which was supported by tilt-table testing results. Although nonpharmacologic treatments were initially successful, episodes of lightheadedness, chest pain, and dyspnea upon standing became more frequent, and the patient was prescribed droxidopa (200 mg; 3 times daily). Droxidopa significantly improved her symptoms, with the patient reporting resolution of her chest pain and significant improvement of dyspnea and dizziness. She was diagnosed with Parkinson disease approximately 6 months later.

Conclusions

This case highlights the importance of evaluating and identifying potential causes of symptoms of cardiovascular disease when persistent symptoms do not improve after cardiac interventions. This case complements findings demonstrating that signs of autonomic failure, such as neurogenic orthostatic hypotension, may precede the motor symptoms of Parkinson disease. Importantly, this case provides real-world evidence for the efficacy of droxidopa to treat the symptoms of neurogenic orthostatic hypotension, after an appropriate diagnosis.

High-salt diet does not boost neuroinflammation and neurodegeneration in a model of α-synucleinopathy

AIM

Pre-clinical studies in models of multiple sclerosis and other inflammatory disorders suggest that high-salt diet may induce activation of the immune system and potentiate inflammation. However, high-salt diet constitutes a common non-pharmacological intervention to treat autonomic problems in synucleinopathies such as Parkinson's disease and multiple system atrophy. Since neuroinflammation plays an important pathogenic role in these neurodegenerative disorders, we asked here whether high-salt diet may aggravate the disease phenotype in a transgenic model of multiple system atrophy.

METHODS

Nine-month-old PLP-hαSyn and matched wildtype mice received normal or high-salt diet for a period of 3 months. Behavioral, histological, and molecular analyses were performed to evaluate the effect of high-salt diet on motor decline, neuroinflammation, neurodegeneration, and α-synuclein accumulation in these mice.

RESULTS

Brain subregion-specific molecular and histological analyses showed no deleterious effects of high-salt diet on the level of microglial activation. Moreover, neuroinflammation-related cytokines and chemokines, T cell recruitment or astrogliosis were unaffected by high-salt diet exposure. Behavioral testing showed no effect of diet on motor decline. High-salt diet was not related to the deterioration of neurodegeneration or α-synuclein accumulation in PLP-hαSyn mice.

CONCLUSIONS

Here, we demonstrate that high-salt diet does not aggravate neuroinflammation and neurodegeneration in PLP-hαSyn mice. Our findings discard a deleterious pro-neuroinflammatory effect of high-salt diet in multiple system atrophy.

Neurogenic Orthostatic Hypotension in Parkinson Disease: A Primer

Parkinson disease (PD) is associated with a variety of motor and non-motor clinical manifestations, including cardiovascular autonomic dysfunction. Neurogenic orthostatic hypotension (nOH) is a potentially serious manifestation of cardiovascular sympathetic failure that occurs in approximately 30% of patients with PD. Here we review the pathophysiology and effects of the condition as well as treatment considerations for patients with PD and nOH. Screening for nOH using orthostatic symptom questionnaires, orthostatic blood pressure measurements, and specialized autonomic testing is beneficial for the identification of symptomatic and asymptomatic cases because cardiac sympathetic denervation and nOH can occur even at early (premotor) stages of PD. Symptoms of nOH, such as orthostatic lightheadedness, in patients with PD, have been shown to adversely affect patient safety (with increased risk of falls) and quality of life and should prompt treatment with non-pharmacologic and, occasionally, pharmacologic measures. Patients with nOH are also at increased risk of supine hypertension, which requires balancing various management strategies. FUNDING: Lundbeck (Deerfield, IL).

Aerobic Training and Mobilization Early Post-stroke: Cautions and Considerations

Knowledge gaps exist in how we implement aerobic exercise programs during the early phases post-stroke. Therefore, the objective of this review was to provide evidence-based guidelines for pre-participation screening, mobilization, and aerobic exercise training in the hyper-acute and acute phases post-stroke. In reviewing the literature to determine safe timelines of when to initiate exercise and mobilization we considered the following factors: arterial blood pressure dysregulation, cardiac complications, blood-brain barrier disruption, hemorrhagic stroke transformation, and ischemic penumbra viability. These stroke-related impairments could intensify with inappropriate mobilization/aerobic exercise, hence we deemed the integrity of cerebral autoregulation to be an essential physiological consideration to protect the brain when progressing exercise intensity. Pre-participation screening criteria are proposed and countermeasures to protect the brain from potentially adverse circulatory effects before, during, and following mobilization/exercise sessions are introduced. For example, prolonged periods of standing and static postures before and after mobilization/aerobic exercise may elicit blood pooling and/or trigger coagulation cascades and/or cerebral hypoperfusion. Countermeasures such as avoiding prolonged standing or incorporating periodic lower limb movement to activate the venous muscle pump could counteract blood pooling after an exercise session, minimize activation of the coagulation cascade, and mitigate potential cerebral hypoperfusion. We discuss patient safety in light of the complex nature of stroke presentations (i.e., type, severity, and etiology), medical history, comorbidities such as diabetes, cardiac manifestations, medications, and complications such as anemia and dehydration. The guidelines are easily incorporated into the care model, are low-risk, and use minimal resources. These and other strategies represent opportunities for improving the safety of the activity regimen offered to those in the early phases post-stroke. The timeline for initiating and progressing exercise/mobilization parameters are contingent on recovery stages both from neurobiological and cardiovascular perspectives, which to this point have not been specifically considered in practice. This review includes tailored exercise and mobilization prescription strategies and precautions that are not resource intensive and prioritize safety in stroke recovery.

Aortic stiffness and central systolic pressure are associated with ambulatory orthostatic BP fall in chronic kidney disease

OBJECTIVE

Orthostatic hypotension (OH) has a significant association with cardiovascular disease. OH becomes more common in older age, as does arterial stiffness, shown to be independently associated with impaired baroreflex sensitivity and OH. Measurement of arterial compliance and central blood pressures are increasingly important, with evidence that central BP more closely correlates to end-organ damage and mortality than peripheral measurements. Patients with chronic kidney disease (CKD) are high risk for cardiovascular events, which can be predicted through measures of arterial compliance. We hypothesised that OH is associated with arterial stiffness and central blood pressure in CKD patients.

DESIGN/SETTING

We tested this hypothesis within the arterial compliance and oxidant stress as predictors of loss of renal function, morbidity and mortality in chronic kidney disease (ACADEMIC) study, a single-centre prospective observational study of the progression of arterial stiffness and renal function.

PARTICIPANTS

One hundred and forty-six patients with CKD 3 or 4.

MEASUREMENTS

Twenty-four-hour ambulatory BP monitoring with postural sensing (DIASYS Integra 2, Novacor France); central systolic and diastolic BP (cSBP and cDBP) and aortic Augmentation Index using Sphygmocor^® (Atcor, Australia); Carotid-femoral pulse wave velocity (cfPWV) using Complior^® (ALAM Medical, France).

RESULTS

Twenty-three patients had a postural SBP fall (prevalence 15.8%), with mean drop 7 mmHg. Patients with OH had higher cfPWV (15.2 m/s vs 12.7 m/s in patients without OH, p < 0.001) and central SBP (147.5 vs 135.7, p = 0.012). Regression analysis gave an odds ratio (OR) of orthostatic SBP fall for cfPWV of 1.46 (95% CI 1.16-1.84, p = 0.001) and 1.03 for cSBP (95% CI 1.004-1.06, p = 0.024) after adjustment for cardiovascular risk factors.

CONCLUSION

Aortic stiffness and central SBP are independently associated with orthostatic SBP fall in CKD patients. This suggests that enhanced arterial stiffness may be an underlying mechanism in baroreflex dysfunction, and may partly explain the vascular risk in CKD patients.

(r)Alpha Lipoic Acid Is a Safe, Effective Pharmacologic Therapy of Chronic Orthostatic Hypotension Associated with Low Sympathetic Tone

Chronic orthostatic hypotension (OH), affecting 10 to 30% of the elderly, is associated with falls, and increased morbidity and mortality. Current pharmacologic therapy can cause or worsen hypertension and fluid retention. (r)α lipoic acid (ALA), a powerful natural antioxidant, avoids those complications and may assist management of chronic neurogenic orthostatic hypotension (NOH). The purpose of this study is to demonstrate improvement in the symptoms of orthostatic dysfunction with r-ALA, including improved sympathetic (S) and blood pressure (BP) responses to head-up postural change (standing). A cohort of 109 patients with low S tone upon standing was detected using the ANX -3.0, Autonomic Monitor, ANSAR Medical Technologies, Inc., Philadelphia, PA. From the cohort, 29 patients demonstrated NOH (change in (∆) standing BP ≥ -20/-10 mm Hg); 60 patients demonstrated orthostatic intolerance (OI, ∆ standing systolic BP between -6 and -19 mm Hg). These 89 were given ALA orally: either 590 to 788 mg (r)ALA or 867 to 1,500 mg of the less expensive 50 to 50% mixture (r)ALA and inactive (s)ALA. Changes in their S and parasympathetic (P) tone, and BPs, were compared with 20 control patients during mean follow-up of 2.28 years. Nineteen of 29 (66%) NOH patients responded with a ∆ standing BP from -28/-6 mm Hg to 0/+2 mm Hg. Forty of 60 (67%) of patients with OI responded with a ∆ standing BP of -9/+1 mm Hg to +6/+2 mm Hg. Although all patients treated with ALA increased S tone, the ∆ BP depended upon the pretreatment of S tone. Those with the lowest S tone responded the least well. The only treatment side effects were nausea, intolerable in only 5%. Nausea improved with routine gastrointestinal medications. Glucose levels improved in the 28% of patients who were diabetic. Also, resting hypertension improved. Control patients had no ∆ BP and no increase in S tone. (r)ALA improves S-, and BP, responses to head-up postural change, and thereby NOH/OI, in a majority of patients without causing harmful side effects.

Role of nurses and nurse practitioners in the recognition, diagnosis, and management of neurogenic orthostatic hypotension: a narrative review

Neurogenic orthostatic hypotension (nOH) is a sustained reduction in blood pressure (BP) upon standing that is caused by autonomic dysfunction and is common among patients with a variety of neurodegenerative disorders (eg, Parkinson's disease, multiple system atrophy, pure autonomic failure). A systolic BP drop of ≥20 mmHg (or ≥10 mmHg diastolic) upon standing with little or no compensatory increase in heart rate is consistent with nOH. Symptoms of nOH include light-headedness, dizziness, presyncope, and syncope; these symptoms can severely impact patients' activities of daily living and increase the likelihood of potentially dangerous falls. Because of their patient contact, nurses and nurse practitioners can play a key role in identifying and evaluating patients at risk for nOH. It is advisable to screen for nOH in patients presenting with one or more of the following characteristics: those who have disorders associated with autonomic failure, those with episodes of falls or syncope, those with symptoms upon standing, those who are elderly or frail, or those taking multiple medications. Initial evaluations should include questions about postural symptoms and measurement of orthostatic BP and heart rate. A review of medications for potential agents that can have hypotensive effects should be performed before initiating treatment. Treatment for nOH may include non-pharmacologic measures and pharmacologic therapy. Droxidopa and midodrine are approved by the US Food and Drug Administration for the treatment of symptomatic nOH and symptomatic OH, respectively. nOH is associated with the coexistence of supine hypertension, and the two disorders must be carefully managed. In conclusion, timely screening and diagnosis of patients with nOH can streamline the path to disease management and treatment, potentially improving patient outcomes.

Six-Month Use of Droxidopa for Neurogenic Orthostatic Hypotension

Background

Droxidopa is approved for adult patients with symptomatic neurogenic orthostatic hypotension (nOH); there is limited information regarding effects on symptoms, outcomes, and quality of life (QOL) beyond two weeks of treatment.

Objective

Examine the real‐world experience of patients taking droxidopa after six months of treatment.

Methods

This non‐interventional, US‐based, prospective cohort study utilized a pharmacy hub, identifying patients who recently started droxidopa for nOH treatment. Questionnaires for fall frequency and other patient‐reported outcomes (PROs) were completed at baseline and one, three, and six months following droxidopa initiation.

Results

179 enrolled patients completed baseline surveys. Droxidopa continuation rates were high at months one, three, and six (87%, 79%, and 75%, respectively). From baseline to month one, there was significant reduction in the proportion of patients reporting falling at least once (54.1% vs. 43.0%; P = 0.0039), with similar observations at month three (52.9% vs. 44.5%; P = 0.0588) and month six (51.4% vs. 40.0%; P = 0.0339). Significant improvements from baseline to month one were observed and maintained at months three and six for most PROs, including the Orthostatic Hypotension Symptom Assessment Item 1, Short Falls Efficacy Scale‐International, Sheehan Disability Scale, Physical Component of the 8‐item Short‐Form Health Survey, and Patient Health Questionnaire‐9.

Conclusions

In this non‐interventional prospective study, fewer nOH patients reported falling after one, three, and six months of droxidopa treatment. Further, improvements reported in nOH symptoms, physical function, and QOL measures were maintained for six months following treatment initiation. Results from randomized clinical trials are required to validate the findings.

Treatment of Orthostatic Hypotension Due to Autonomic Dysfunction (Neurogenic Orthostatic Hypotension) in a Patient with Cardiovascular Disease and Parkinson's Disease

INTRODUCTION

The prevalence of neurogenic orthostatic hypotension (nOH) increases with age and is associated with autonomic failure in neurodegenerative diseases (e.g., Parkinson's disease). Symptoms can interfere with daily activities that require standing or walking and can increase risk of falls and related morbidity. Many patients with nOH have or develop cardiovascular comorbidities that can predate nOH symptoms or may arise as a result of autonomic dysregulation. In this report, we describe a complicated case of a patient with cardiovascular disease and Parkinson's disease who presented with orthostatic symptoms.

CASE REPORT

A 78-year-old man with a history of coronary heart disease, class III heart failure, cardiac cachexia, long-standing persistent atrial fibrillation (AF), Hodgkin's lymphoma, and Parkinson's disease presented with weakness, dizziness, presyncope, fatigue, and inability to stand. Orthostatic blood pressure (BP) measurements revealed a seated BP of 120/70 mmHg that decreased to 60/40 mmHg upon standing, accompanied by a slight increase in heart rate from 70 to 74 beats per minute. He was diagnosed with nOH and prescribed droxidopa (titrated to 600 mg three times daily). Treatment with droxidopa improved the patient's ability to stand and his orthostatic BP.

CONCLUSION

Droxidopa is approved by the US Food and Drug Administration to treat symptomatic nOH and is not contraindicated in patients with cardiovascular conditions. In this case, treatment with droxidopa improved the patient's orthostatic tolerance and, importantly, did not change the patient's rate-controlled AF or his symptoms of class IV heart failure. Because symptoms associated with nOH can be detrimental to patient safety and mobility, it is critical to screen for and treat patients with nOH, even when there are cardiovascular comorbidities.

FUNDING

Editorial support and article processing charges were funded by Lundbeck. Plain language summary available for this article.

Characterization of the symptoms of neurogenic orthostatic hypotension and their impact from a survey of patients and caregivers

Background

Neurogenic orthostatic hypotension (nOH) results from impaired vasoconstriction due to dysfunction of the autonomic nervous system and is commonly associated with Parkinson disease (PD), multiple system atrophy (MSA), and pure autonomic failure. nOH can increase the risk of falls due to symptoms that include postural lightheadedness or dizziness, presyncope, and syncope. The purpose of this study was to obtain information from patients and caregivers regarding the symptoms and burden of nOH to expand on limited knowledge regarding the impact of nOH on quality of life.

Methods

This author-designed survey included questions regarding nOH (e.g., frequency and impact of symptoms, management) and was conducted online by Harris Poll via distribution to individuals who agreed to participate in Harris Poll online surveys or who were members of relevant disease advocacy organizations. Eligible patients were aged ≥ 18 years with PD, MSA, or pure autonomic failure and ≥ 1 of the following: orthostatic hypotension (OH), nOH, low blood pressure upon standing, or OH/nOH symptoms. Eligible caregivers cared for such patients but were not necessarily linked to any patient participant.

Results

Survey responses were received from 363 patients and 128 caregivers. PD was the most frequent underlying disorder (90% of patients; 88% of individuals managed by the caregivers). Despite meeting survey diagnosis criteria, a formal diagnosis of OH or nOH was reported by only 36% of patients and 16% of caregivers. The most frequent symptoms of nOH were dizziness or lightheadedness, fatigue when standing, and difficulty walking. A negative impact on patient quality of life caused by nOH symptoms was reported by 59% of patients and 75% of caregivers. Most respondents (≥87%) reported that nOH symptoms adversely affected patients’ ability to perform everyday activities (most frequently physical activity/exercise, housework, and traveling). Falls (≥1) in the previous year due to nOH symptoms were reported by 57% of patients and 80% of caregivers.

Conclusions

These survey results support the premise that nOH symptoms have a substantial negative impact on patient function and quality of life. The relatively low rates of formal nOH/OH diagnosis suggest the need for heightened awareness regarding the condition and its symptom burden.

Electronic supplementary material

The online version of this article (10.1186/s12883-018-1129-x) contains supplementary material, which is available to authorized users.

Standing and Supine Blood Pressure Outcomes Associated With Droxidopa and Midodrine in Patients With Neurogenic Orthostatic Hypotension: A Bayesian Meta-analysis and Mixed Treatment Comparison of Randomized Trials

BACKGROUND

The comparative effects of droxidopa and midodrine on standing systolic blood pressure (sSBP) and risk of supine hypertension in patients with neurogenic orthostatic hypotension (NOH) are unknown.

OBJECTIVE

To perform a Bayesian mixed-treatment comparison meta-analysis of droxidopa and midodrine in the treatment of NOH.

METHODS

The PubMed, CENTRAL, and EMBASE databases were searched up to November 16, 2016. Study selection consisted of randomized trials comparing droxidopa or midodrine with placebo and reporting on changes in sSBP and supine hypertension events. Data were pooled to perform a comparison among interventions in a Bayesian fixed-effects model using vague priors and Markov chain Monte Carlo simulation with Gibbs sampling, calculating pooled mean changes in sSBP and risk ratios (RRs) for supine hypertension with associated 95% credible intervals (CrIs).

RESULTS

Six studies (4 administering droxidopa and 2 administering midodrine) enrolling a total of 783 patients were included for analysis. The mean change from baseline in sSBP was significantly greater for both drugs when compared with placebo (droxidopa 6.2 mm Hg [95% CrI = 2.4-10] and midodrine 17 mm Hg [95% CrI = 11.4-23]). Comparative analysis revealed a significant credible difference between droxidopa and midodrine. The RR for supine hypertension was significantly greater for midodrine, but not droxidopa, when compared with placebo (droxidopa RR = 1.4 [95% CrI = 0.7-2.7] and midodrine RR = 5.1 [95% CrI = 1.6-24]). Conclusion and Relevance: In patients with NOH, both droxidopa and midodrine significantly increase sSBP, the latter to a greater extent. However, midodrine, but not droxidopa, significantly increases risk of supine hypertension.

Delayed orthostatic hypotension: Severity of clinical symptoms and response to medical treatment

INTRODUCTION

Severity of orthostatic intolerance and the benefit of medical treatment in patients with delayed OH have not been elucidated. This study aimed to compare the symptom severity between classic and delayed OH and evaluate the efficacy of midodrine or pyridostigmine in patients with delayed OH.

METHODS

This was an adjunctive study of previously reported randomized, open-label clinical trials evaluating the efficacy and safety of midodrine or pyridostigmine for classic OH. Seventeen patients with delayed OH were enrolled and also received midodrine (2.5 mg twice a day) or pyridostigmine (30 mg twice a day) alone or combined. Result of initial orthostatic vital sign and questionnaires were compared between the patients with delayed OH and previously reported 87 patients with classic OH. Delayed OH patients were followed up at 1 and 3 months post-treatment and the vital sign measurements and questionnaires were repeated during the follow-up period.

RESULTS

Questionnaire scores regarding OH-related symptoms, depression and health-related quality of life (HRQOL) were comparable between the classic and delayed OH patients at baseline. OH-related symptoms and depression were significantly improved after 3 months of medical treatment.

CONCLUSION

Patients with delayed OH exhibited orthostatic intolerance similar to that of classic OH. This study shows that these patients may benefit from medical treatment with either midodrine or pyridostigmine.

Morning blood pressure surge is associated independently with orthostatic hypotension in hypertensive patients under treatment

OBJECTIVE

Morning blood pressure surge (MBPS) and orthostatic hypotension (OH) play a role in the occurrence of cardiovascular events. We aimed to investigate the association between MBPS and OH in hypertensive patients under treatment.

PATIENTS AND METHODS

We prospectively included 297 patients (mean age: 53.8±10.7 years, male/female: 101/196) with essential hypertension. Tilt table testing was performed for the diagnosis of OH. OH was classified into three groups as initial OH (0-15 s), classical OH (15 s to 3 min), and delayed OH (3-30 min). Patients were categorized into two main groups: patient with OH or without OH. We used sleep-through MBPS. The MBPS was calculated as the difference between the average blood pressure (BP) during the 2 h after awakening and the lowest night-time BP.

RESULTS

We detected initial OH in two patients, classic OH in seven patients, delayed OH in 20 patients, and delayed OH with syncope in two patients. MBPS, thiazide diuretic, and α-blocker treatments were found to be associated independently with the occurrence of OH. Every 10 mmHg increase in MBPS was found to increase the rate of development of OH by 29.6%. The cut-off value of MBPS obtained by the receiver operator characteristic curve analysis was 35 mmHg for the prediction of OH occurrence (sensitivity: 58.0%, specificity: 68.0%). The area under the curve was 0.657 (95% confidence interval: 0.553-0.771, P=0.004).

CONCLUSION

OH is a major problem in hypertensive patients. Increased MBPS, which can be detected easily by 24-h ambulatory BP monitor, predicts the occurrence of OH independently.

Patterns of Orthostatic Blood Pressure Changes in Patients with Orthostatic Hypotension

Background and Purpose

The objective of this study was to determine the patterns of blood pressure (BP) changes during the head-up tilt (HUT) test, particularly in terms of its clinical significance for patients with orthostatic hypotension (OH).

Methods

OH was divided into four categories based on systolic BP changes occurring within the first 10 minutes of the HUT test: sustained orthostatic hypotension (SOH), progressive orthostatic hypotension (POH), orthostatic hypotension with partial recovery (OHPR), and transient orthostatic hypotension (TOH).

Results

In total, 151 patients were analyzed: 65 with SOH, 38 with POH, 21 with OHPR, and 27 with TOH. POH patients exhibited the greatest reduction in systolic BP after HUT and were also the most likely to develop symptoms requiring early termination of the HUT test (42.1%, p<0.001). Additionally, SOH patients exhibited smaller heart-rate variation with deep breathing values (p=0.003) and Valsalva ratios (p=0.022) compared to POH patients. The sweat volume was greatest in OHPR patients.

Conclusions

Clinical characteristics, including the findings of autonomic function tests, differed between the OH patient groups. This might reflect differences in the underlying pathophysiologic mechanisms. Determining the patterns of BP changes during the HUT test may facilitate the development of effective management strategies in patients with OH.

Effectiveness of droxidopa compared to midodrine in standing blood pressure and orthostatic tolerance in adults with neurogenic orthostatic hypotension: a systematic review protocol

REVIEW QUESTION

The question of this review is: what is the effectiveness of droxidopa compared to midodrine on standing blood pressure and orthostatic intolerance symptoms in adults with neurogenic orthostatic hypotension?

Fall-related healthcare use and costs in neurogenic orthostatic hypotension with Parkinson's disease

AIMS

To compare patient characteristics, rates, and costs of medically attended falls among patients with Parkinson's disease (PD) and probable PD plus neurogenic orthostatic hypotension (PD + nOH).

MATERIALS AND METHODS

MarketScan Commercial and Medicare Supplemental databases (January 1, 2009-December 31, 2013) were used to identify PD and probable PD + nOH patients. The first medical or prescription claim suggesting these diagnoses served as the index date. Baseline characteristics and post-index all-cause and fall-related healthcare utilization and costs were compared between patient groups.

RESULTS

A total of 17,421 PD and 281 PD + nOH patients were identified. Compared with PD patients, PD + nOH patients were older (77 vs 74 years; p < .0001) and had more comorbidities. Pre- and post-index date, more PD + nOH patients had a medically attended fall than PD patients (25% vs 20% [p = .0159] and 30% vs 21% [p = 0.0002], respectively). Fallers in both groups had similar numbers of medically attended falls 12-months pre-index (mean =1.9), but PD + nOH fallers had more falls post-index (2.5 vs 2.0; p = .0176). Compared with PD patients, more PD + nOH patients (all p < .01) had fall-related emergency department (ED) visits (18% vs 10%), hospitalizations (7% vs 3%), and non-office visit outpatient services (15% vs 10%). Adjusted total post-index medical costs for falls ($2,260 vs $1,049; p = .0002) and total all-cause costs ($31,260 vs $20,910; p < .0001) were higher for PD + nOH vs PD patients.

LIMITATIONS

This study had some limitations. There is no ICD-9-CM diagnosis code for nOH, so a combination of PD and OH diagnoses (with confounding conditions excluded) served as a proxy for an nOH diagnosis. Also, the rate of falls and associated costs in these cohorts might be under-reported because only medically attended falls were evaluated.

CONCLUSIONS

PD + nOH patients had a higher prevalence of pre-existing comorbidities and a higher rate of medically attended falls than those with PD alone, leading to increased costs of care.

Office orthostatic blood pressure measurements and ambulatory blood pressure monitoring in the prediction of autonomic dysfunction

Background

In this retrospective analysis we investigated the predictive performance of orthostatic hypotension (OH) and ambulatory blood pressure monitoring (ABP) to predict autonomic dysfunction.

Methods

Statistical associations among the candidate variables were investigated and comparisons of predictive performances were performed using Receiver Operating Characteristics (ROC) curves.

Results

Ninety-four patients were included for analysis. No significant correlations could be demonstrated between OH and components of ABP (reversal of circadian pattern, postprandial hypotension and heart rate variability), nor between OH and autonomic reflex screen. Reversal of circadian pattern did not demonstrate significant correlation (r = 0.12, p = 0.237) with autonomic reflex screen, but postprandial hypotension (r = 0.39, p = 0.003) and heart rate variability (r = 0.27, p = 0.009) demonstrated significant correlations. Postprandial hypotension was associated with a five-fold (OR 4.83, CI95% 1.6–14.4, p = 0.005) increased risk and heart rate variability with a four-fold (OR 3.75, CI95% 1.3–10.6, p = 0.013) increased risk for autonomic dysfunction. Per ROC curves, heart rate variability (0.671, CI_95% 0.53–0.81, p = 0.025) and postprandial hypotension (0.668, CI_95% 0.52–0.72, p = 0.027) were among the best predictors of autonomic dysfunction in routine clinical practice.

Conclusion

Postprandial hypotension and heart rate variability on ambulatory blood pressure monitoring are among the best predictors of autonomic dysfunction in routine clinical practice.