Survival in synucleinopathies: A prospective cohort study

Impact of autonomic symptoms on the clinical course of Parkinson's disease

PURPOSE

Patients with Parkinson's disease (PD) exhibit various degrees of autonomic symptoms, which may be associated with Lewy body pathology distributed extensively in the autonomic nervous system. We hypothesized that the severity of autonomic symptoms reflects the severity of PD-related pathology, resulting in poor outcomes. The purpose of this study was to evaluate the impact of autonomic symptoms on PD progression.

METHODS

We conducted a follow-up study among consecutive patients with PD at Dokkyo Medical University Hospital. Patients underwent comprehensive baseline evaluations and were classified into high and low autonomic symptom groups using the Scale for Outcomes in Parkinson's Disease-Autonomic (SCOPA-AUT). The Kaplan‒Meier survival curves were used to analyze the time to discontinuation of their visits because of PD-related endpoints and to evaluate the association with high SCOPA-AUT scores.

RESULTS

Of the 101 patients, 74 (73%) met the inclusion criteria. During the follow-up period (mean 1654 days), 22/74 patients reached PD-related endpoints (death, 4; hospitalization, 9; nursing home institutionalization, 9). PD patients with high SCOPA-AUT scores reached the endpoints faster than those with low SCOPA-AUT scores. A high SCOPA-AUT score, including gastrointestinal, urinary, and thermoregulation domains; high motor symptom scores; and low specific binding ratios (SBRs) on 123I FP-CIT-SPECT (DAT-SPECT) were associated with reaching PD-related endpoints. A high SCOPA-AUT score was associated with reaching the endpoints even after adjustment for covariates.

CONCLUSIONS

Patients with high autonomic symptom scores had a greater risk of reaching PD-related endpoints than patients with low autonomic symptom scores.

Ethical Considerations for Identifying Individuals in the Prodromal/Early Phase of Parkinson's Disease: A Narrative Review

The ability to identify individuals in the prodromal phase of Parkinson's disease has improved in recent years, raising the question of whether and how those affected should be informed about the risk of future disease. Several studies investigated prognostic counselling for individuals with isolated REM sleep behavior disorder and have shown that most patients want to receive information about prognosis, but autonomy and individual preferences must be respected. However, there are still many unanswered questions about risk disclosure or early diagnosis of PD, including the impact on personal circumstances, cultural preferences and specific challenges associated with different profiles of prodromal symptoms, genetic testing or biomarker assessments. This narrative review aims to summarize the current literature on prognostic counselling and risk disclosure in PD, as well as highlight future perspectives that may emerge with the development of new biomarkers and their anticipated impact on the definition of PD.

Abnormal Cerebrovascular Activity, Perfusion, and Glymphatic Clearance in Lewy Body Diseases

Cerebrovascular activity is not only crucial to optimal cerebral perfusion, but also plays an important role in the glymphatic clearance of interstitial waste, including α-synuclein. This highlights a need to evaluate how cerebrovascular activity is altered in Lewy body diseases. This review begins by discussing how vascular risk factors and cardiovascular autonomic dysfunction may serve as upstream or direct influences on cerebrovascular activity. We then discuss how patients with Lewy body disease exhibit reduced and delayed cerebrovascular activity, hypoperfusion, and reductions in measures used to capture cerebrospinal fluid flow, suggestive of a reduced capacity for glymphatic clearance. Given the lack of an existing framework, we propose a model by which these processes may foster α-synuclein aggregation and neuroinflammation. Importantly, this review highlights several avenues for future research that may lead to treatments early in the disease course, prior to neurodegeneration. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Hypotensive episodes at 24-h ambulatory blood pressure monitoring predict adverse outcomes in Parkinson's disease

PURPOSE

Neurogenic orthostatic hypotension (nOH) is a frequent nonmotor feature of Parkinson's disease (PD), associated with adverse outcomes. Recently, 24-h ambulatory blood pressure monitoring (ABPM) showed good accuracy in diagnosing nOH. This study aims at evaluating the prognostic role of ABPM-hypotensive episodes in predicting PD disability milestones and mortality and comparing it to the well-defined prognostic role of bedside nOH.

METHODS

Patients with PD who underwent ABPM from January 2012 to December 2014 were retrospectively enrolled and assessed for the development of falls, fractures, dementia, bed/wheelchair confinement, hospitalization, and mortality, during an up-to-10-year follow-up. Significant ABPM-hypotensive episodes were identified when greater than or equal to two episodes of systolic BP drop ≥ 15 mmHg (compared with the average 24 h) were recorded during the awakening-to-lunch period.

RESULTS

A total of 99 patients (74% male, age 64.0 ± 10.1 years, and PD duration 6.4 ± 4.0 years) were enrolled. At baseline, 38.4% of patients had ABPM-hypotensive episodes and 46.5% had bedside nOH. On Kaplan-Meier analysis, patients with ABPM-hypotensive episodes showed earlier onset of falls (p = 0.001), fractures (p = 0.004), hospitalizations (p = 0.009), bed/wheelchair confinement (p = 0.032), dementia (p = 0.001), and shorter survival (8.0 versus 9.5 years; p = 0.009). At Cox regression analysis (adjusted for age, disease duration, Charlson Comorbidity Index, and Hoehn and Yahr stage) a significant association was confirmed between ABPM-hypotensive episodes and falls [odds ratio (OR) 3.626; p = 0.001), hospitalizations (OR 2.016; p = 0.038), and dementia (OR 2.926; p = 0.008), while bedside nOH was only associated with falls (OR 2.022; p = 0.039) and dementia (OR 1.908; p = 0.048).

CONCLUSIONS

The presence of at least two ABPM-hypotensive episodes independently predicted the development of falls, dementia, and hospitalization, showing a stronger prognostic value than the simple bedside assessment.

Hypotensive episodes at 24-h Ambulatory Blood Pressure Monitoring predict adverse outcomes in Parkinson's Disease

Purpose

Neurogenic orthostatic hypotension (nOH) is a frequent non-motor feature of Parkinson's disease (PD), associated with adverse outcomes. Recently, 24-hour ambulatory BP monitoring (ABPM) has been shown to diagnose nOH with good accuracy (in the presence of at least 2 episodes of systolic BP drop ≥ 15 mmHg compared to the average 24-h). This study aims at evaluating the prognostic role of ABPM-hypotensive episodes in predicting PD disability milestones and mortality and comparing it to well-defined prognostic role of nOH.

Methods

PD patients who underwent ABPM from January 2012 to December 2014 were retrospectively enrolled and assessed for the development of falls, fractures, dementia, bed/wheelchair confinement, hospitalization, mortality, during an up-to-10-year follow-up.

Results

Ninety-nine patients (male 74%; age: 64.0 ± 10.1 years; PD duration: 6.4 ± 4.0 years) were enrolled. At baseline, 38.4% of patients had ABPM-hypotensive episodes and 46.5% had bedside nOH.At Kaplan-Meier analysis patients with ABPM-hypotensive episodes had an earlier onset of falls (p = 0.001), fractures (p = 0.004), hospitalizations (p = 0.009), bed/wheelchair confinement (p = 0.032), dementia (p = 0.001), and showed a shorter survival (8.0vs9.5 years; p = 0.009). At Cox regression analysis (adjusted for age, disease duration, Charlson Comorbidity Index, and H&Y stage at baseline) a significant association was confirmed between ABPM-hypotensive episodes and falls (OR:3.626; p = 0.001), hospitalizations (OR:2.016; p = 0.038), and dementia (OR:2.926; p = 0.008), while bedside nOH was only associated with falls (OR 2.022; p = 0.039) and dementia (OR:1.908; p = 0.048).

Conclusion

The presence of at least two ABPM-hypotensive episodes independently predicted the development of falls, dementia, and hospitalization, showing a stronger prognostic value than the simple bedside assessment.

Levodopa-induced orthostatic hypotension in parkinsonism: A red flag of autonomic failure

BACKGROUND AND PURPOSE

Levodopa (LD) is the main treatment for parkinsonism, but its use may be limited by a potential hypotensive effect.

METHODS

We evaluated the cardiovascular effect of LD performing head-up tilt test (HUTT) before and 60 min after 100/25 mg LD/dopa-decarboxylase inhibitor (pre-LD vs. post-LD HUTT) in 164 patients with parkinsonism on chronic LD treatment. Features predictive of LD-induced orthostatic hypotension (OH) were assessed by logistic regression analysis.

RESULTS

Basal supine blood pressure (BP) and heart rate (HR) decreased after LD. During post-LD HUTT, BP drop and HR increase were significantly greater than at pre-LD HUTT. Thirty-eight percent of patients had OH at post-LD HUTT compared to 22% of patients presenting OH at pre-LD HUTT (p < 0.001). Risk factors for LD-induced/worsened OH were pre-LD OH (odds ratio [OR] = 36, 95% confidence interval [CI] = 10-131), absence of overshoot at Valsalva maneuver (OR = 9, 95% CI = 4-20), and pathological Valsalva ratio (OR = 6, 95% CI = 2-15).

CONCLUSIONS

LD administration caused/worsened hypotension in both supine and orthostatic conditions. Patients with cardiovascular autonomic failure had a higher risk of developing LD-induced OH. In clinical practice, LD-induced OH could represent a red flag for cardiovascular autonomic failure.

Effect of Levodopa on Heat Hypersensitivity and Complex Motor Parkinsonism

OBJECTIVES

The aim of the study is to report a case with heat intolerance, complex motor fluctuations, and parkinsonism.

MATERIALS AND METHODS

A male with onset of heat intolerance at the age of 46 years developed left upper limb tremor at the age of 58 years. He was diagnosed with Parkinson disease at the age of 62 years and presented to Movement Disorders Clinic Saskatchewan at the age of 65 years. He reported motor response fluctuations, including WO and dyskinesias. There was no history of dizziness on standing, bladder, or sexual dysfunction. We recorded an asymptomatic drop of orthostatic blood pressure. He reported loss of smell sensation for 5 years and REM behavior disorder characterized by talking in his sleep. He was assessed at the age of 65 years over the course of a day with 4 video recordings of his evolving findings and symptoms with his informed consent.

RESULTS

Initial assessment after levodopa was withheld more than 14 hours revealed him to be 'off' with severe dystonic neck flexion and with bradykinesia and rigidity in the limbs. He was anhidrotic, felt hot, and needed a wet towel over his neck. Over the course of 4 hours, he turns "on" with improvement in heat intolerance, neck hypertonicity, and parkinsonian findings and develops evolving dyskinetic movements before turning "off" again. His overall clinical picture was most consistent with multiple system atrophy.

CONCLUSIONS

Heat intolerance can precede onset of motor symptoms of parkinsonism by several years and supports a diagnosis of multiple system atrophy. To our knowledge, this is the first documented case of improvement in heat intolerance with levodopa.

An overview on pure autonomic failure

Pure autonomic failure (PAF) is a neurodegenerative disease affecting the sympathetic component of the autonomic nervous system and presenting as orthostatic hypotension (OH). It is a rare, sporadic disease of adults. Although OH is the primary symptom, the autonomic dysfunction may be more generalised, leading to genitourinary and intestinal dysfunction and sweating disorders. Autonomic symptoms in PAF may be similar to those observed in other autonomic neuropathies that need to be ruled out. PAF belongs to the group of α synucleinopathies and is characterised by predominant peripheral deposition of α-synuclein in autonomic ganglia and nerves. However, in a significant number of cases, PAF may convert into another synucleinopathy with central nervous system involvement with varying prognosis: Parkinson's disease (PD), multiple system atrophy (MSA), or dementia with Lewy bodies (DLB). The clinical features, the main differential diagnoses, the risk factors for "phenoconversion" to another synucleinopathy as well as an overview of treatment will be discussed.

Cardiac 18F-dopamine positron emission tomography predicts the type of phenoconversion of pure autonomic failure

PURPOSE

Pure autonomic failure (PAF) is a rare disease characterized by neurogenic orthostatic hypotension (nOH), no known secondary cause, and lack of a neurodegenerative movement or cognitive disorder. Clinically diagnosed PAF can evolve ("phenoconvert") to a central Lewy body disease [LBD, e.g., Parkinson's disease (PD) or dementia with Lewy bodies (DLB)] or to the non-LBD synucleinopathy multiple system atrophy (MSA). Since cardiac 18F-dopamine-derived radioactivity usually is low in LBDs and usually is normal in MSA, we hypothesized that patients with PAF with low cardiac 18F-dopamine-derived radioactivity would be more likely to phenoconvert to a central LBD than to MSA.

METHODS

We reviewed data from all the patients seen at the National Institutes of Health Clinical Center from 1994 to 2023 with a clinical diagnosis of PAF and data about 18F-dopamine positron emission tomography (PET).

RESULTS

Nineteen patients (15 with low 18F-dopamine-derived radioactivity, 4 with normal radioactivity) met the above criteria and had follow-up data. Nine (47%) phenoconverted to a central synucleinopathy over a mean of 6.6 years (range 1.5-18.8 years). All 6 patients with low cardiac 18F-dopamine-derived radioactivity who phenoconverted during follow-up developed a central LBD, whereas none of 4 patients with consistently normal 18F-dopamine PET phenoconverted to a central LBD (p = 0.0048), 3 evolving to probable MSA and 1 upon autopsy having neither a LBD nor MSA.

CONCLUSION

Cardiac 18F-dopamine PET can predict the type of phenoconversion of PAF. This capability could refine eligibility criteria for entry into disease-modification trials aimed at preventing evolution of PAF to symptomatic central LBDs.

Hemodynamic Effects of the Osmopressor Response: A Systematic Review and Meta-Analysis

Background Rapidly consuming water may offer practical orthostatic hypotension therapy. However, its efficacy across disorders remains uncertain. This study aims to assess the impact of rapid 350- to 500-mL water intake on systolic and diastolic blood pressure (BP) and heart rate (HR) through a systematic review and meta-analysis. Methods and Results We systematically reviewed MEDLINE and Embase up to June 2023, including randomized controlled trials and prospective cohort studies. Using random-effects meta-analysis, we calculated pooled mean differences (MDs) for maximum hemodynamic effects of rapid 350- to 500-mL water bolus consumption. Participants with orthostatic hypotension experienced increased systolic BP (MD, 24.18 [95% CI, 15.48-32.88]) and diastolic BP (MD, 11.98 [95% CI, 8.87-15.09]) with decreased HR (MD, -3.46 [95% CI, -5.21 to -1.71]). Similar results were observed in multiple system atrophy and pure autonomic failure subgroup analysis. Healthy participants showed modest increases in systolic BP (MD, 2.33 [95% CI, 1.02-3.64]) and diastolic BP (MD, 2.73 [95% CI, 1.15-4.30]), but HR changes were not significant (MD, -2.06 [95% CI, -5.25 to 1.13]). Water had no significant hemodynamic effects in patients with seated or supine postural tachycardia syndrome, although standing effects were unassessed. Our data do not exclude water's potential standing effect in postural tachycardia syndrome. Conclusions In patients with orthostatic hypotension, rapid water intake elevated short-term systolic BP and diastolic BP, with mild HR reduction when seated or supine. Healthy participants exhibited similar but milder effects. However, patients with postural tachycardia syndrome did not experience these changes in seated or supine positions. Further research is needed to evaluate the promising impact of rapid water ingestion on patients with postural tachycardia syndrome in a standing position, which was not addressed in our study.

Non-Pharmacological Treatment of Autonomic Dysfunction in Parkinson's Disease and Other Synucleinopathies

Symptoms of autonomic dysfunction are prevalent and can be very debilitating, reducing the quality of life in patients with Parkinson's disease (PD) and other synucleinopathies such as dementia with Lewy bodies and multiple system atrophy. Non-pharmacological therapies are key to effective management and are frequently used alone in patients with mild autonomic symptoms, or in combination with pharmacological therapies in patients with moderate and severe symptoms. This article focuses on non-pharmacological approaches. Our objective was to review the non-drug and non-surgical approaches to treating autonomic symptoms in patients with PD and other synucleinopathies, focusing on cardiovascular, gastrointestinal, and genitourinary autonomic dysfunction. Evidence supporting the effectiveness of non-pharmacological treatment for the management of neurogenic orthostatic hypotension, supine hypertension, constipation, and bladder and sexual dysfunction is available. High-quality prospective trials are scarce, yet some non-pharmacological interventions (e.g., physical counter maneuvers) can be evaluated relatively quickly on an individual basis and often seem effective. The emerging variety of clinical presentations advocates for a stepwise, individualized, and non-pharmacological approach for the management of autonomic symptoms. Often, the first step is to reduce or discontinue drugs that cause or aggravate autonomic symptoms followed by lifestyle measures. While non-pharmacological and non-surgical treatments are available and, in many cases, effective to improve symptoms of autonomic dysfunction in PD and other synucleinopathies, they are often overlooked. Large randomized trials testing and comparing non-pharmacological approaches are warranted.

Cardiac 18F-Dopamine Positron Emission Tomography Predicts the Type of Phenoconversion of Pure Autonomic Failure

Background

Pure autonomic failure (PAF) is a rare disease characterized clinically by neurogenic orthostatic hypotension (nOH) and biochemically by peripheral noradrenergic deficiency. Clinically diagnosed PAF can evolve ("phenoconvert") to a central Lewy body disease (LBD, e.g., Parkinson's disease (PD) or dementia with Lewy bodies (DLB)) or to the non-LBD synucleinopathy multiple system atrophy (MSA). We examined whether cardiac 18F-dopamine positron emission tomography (PET) predicts the trajectory of phenoconversion in PAF. Since cardiac 18F-dopamine-derived radioactivity always is decreased in LBDs with nOH and usually is normal in MSA, we hypothesized that PAF patients with low cardiac 18F-dopamine-derived radioactivity may phenoconvert to a central LBD but do not phenoconvert to MSA.

Methods

We reviewed data from all the patients seen at the National Institutes of Health Clinical Center from 1994 to 2023 with a clinical diagnosis of PAF and data about serial 18F-dopamine PET.

Results

Twenty patients met the above criteria. Of 15 with low cardiac 18F-dopamine-derived radioactivity, 6 (40%) phenoconverted to PD or DLB and none to MSA. Of 5 patients with consistently normal 18F-dopamine PET, 4 phenoconverted to MSA, and the other at autopsy had neither a central LBD nor MSA.

Conclusion

In this case series, 40% of patients with nOH and low cardiac 18F-dopamine-derived radioactivity phenoconverted to PD or DLB during follow-up; none phenoconverted to MSA. Cardiac 18F-DA PET therefore can predict the type of phenoconversion in PAF. This capability could refine eligibility criteria for entry into disease-modification trials aiming to prevent evolution of PAF to symptomatic central LBDs.

A 3-year natural history of orthostatic blood pressure dysregulation in early Parkinson's disease

In Parkinson's disease (PD), cardiovascular dysautonomia accumulates with disease progression, but studies are lacking on the natural history behind each subtype except orthostatic hypotension. This study investigated the early natural history of orthostatic blood pressure (BP) subtypes in PD. Two hundred sixty-seven early PD patients were included. Their cardiovascular functions were assessed by head-up tilt-test and ¹²³I-metaiodobenzylguanidine scintigraphy. All patients were classified as having supine hypertension (SH), orthostatic hypertension (OHT), delayed orthostatic hypotension (dOH), or orthostatic hypotension (OH) according to consensus criteria. The patients were assigned to one of three groups: extreme BP dysregulation (BP_extreme), mild BP dysregulation (BP_mild), and no BP dysregulation (BP_none) according to their orthostatic BP subtypes. The autonomic functions of 237 patients were re-assessed after approximately 3 years. Among initially enrolled subjects, 61.8% of the patients showed orthostatic BP dysregulation: 29.6% in the BP_extreme group and 32.2% in the BP_mild group. At follow-up, the BP_extreme group increased in number, while the BP_mild group diminished. Two-thirds of the initial BP_extreme patients maintained their initial subtype at follow-up. In comparison, 40.7% of the initial BP_mild patients progressed to the BP_extreme group, and 32.4% and 14.7% of the initial BP_none group progressed to BP_extreme and BP_mild groups, respectively. Cardiac denervation was most severe in the BP_extreme group, and a linear gradient of impairment was observed across the subtypes. In conclusion, various forms of positional BP dysregulation were observed during the early disease stage. SH and OH increased with disease progression, while OHT and dOH decreased, converting primarily to SH and/or OH.

The noradrenergic subtype of Parkinson disease: from animal models to clinical practice

Many advances in understanding the pathophysiology of Parkinson disease (PD) have been based on research addressing its motor symptoms and phenotypes. Various data-driven clinical phenotyping studies supported by neuropathological and in vivo neuroimaging data suggest the existence of distinct non-motor endophenotypes of PD even at diagnosis, a concept further strengthened by the predominantly non-motor spectrum of symptoms in prodromal PD. Preclinical and clinical studies support early dysfunction of noradrenergic transmission in both the CNS and peripheral nervous system circuits in patients with PD that results in a specific cluster of non-motor symptoms, including rapid eye movement sleep behaviour disorder, pain, anxiety and dysautonomia (particularly orthostatic hypotension and urinary dysfunction). Cluster analyses of large independent cohorts of patients with PD and phenotype-focused studies have confirmed the existence of a noradrenergic subtype of PD, which had been previously postulated but not fully characterized. This Review discusses the translational work that unravelled the clinical and neuropathological processes underpinning the noradrenergic PD subtype. Although some overlap with other PD subtypes is inevitable as the disease progresses, recognition of noradrenergic PD as a distinct early disease subtype represents an important advance towards the delivery of personalized medicine for patients with PD.

Health-related quality-of-life and burden for caregivers of individuals with neurogenic orthostatic hypotension

Aim: This study explores the burden of caring for an individual with neurogenic orthostatic hypotension (nOH) and an underlying neurodegenerative disease (Parkinson's disease, multiple system atrophy, pure autonomic failure or dementia with Lewy bodies). Materials & methods: A survey including several validated instruments was conducted with informal caregivers of individuals with Parkinson's disease, multiple system atrophy, pure autonomic failure or dementia with Lewy bodies. Results: Caregivers of patients with nOH (n = 60) reported greater burden across all outcomes compared with those without nOH (n = 60). Receiving pharmacological treatment for nOH was the variable most consistently associated with significantly better caregiver health-related quality-of-life (p < 0.05). Conclusion: This study demonstrates the burden of nOH on informal caregivers and highlights the potential benefit of pharmacological treatment not only for patients but also indirectly, their caregivers.

Impaired dynamic cerebral autoregulation: A potential mechanism of orthostatic hypotension and dementia in Parkinson’s disease

Background

Orthostatic hypotension (OH) and cognitive impairment are common non-motor symptoms of Parkinson’s disease (PD). This study aimed to investigate whether impaired dynamic cerebral autoregulation (dCA) is associated with OH and Parkinson’s disease dementia (PDD), and analyze the related risk factors in patients with PDD.

Materials and methods

We enrolled 89 patients with PD and 20 age- and sex-matched healthy controls (HCs). Cognition and different cognitive domains were assessed by the Montreal Cognitive Assessment scale. Non-invasive continuous beat-to-beat blood pressure and cerebral blood flow velocity were assessed using a servo-controlled finger plethysmograph and transcranial Doppler, respectively. dCA was examined using supine and orthostatic changes with transfer function analysis to derive the autoregulatory parameters of phase, gain, and coherence. Logistic regression analysis was performed to determine the risk factors for PDD.

Results

We found that 21 (23.6%) patients with PD had OH. These patients showed worse cognitive performance in specific cognitive tasks, such as language and orientation. The patients with OH also had poorer dCA; the very low frequency (VLF) phase in two different postures was lower than that in patients without OH as well as HCs (both P < 0.05). And the normalized gain in the VLF and low frequency (LF) in standing position was higher in PD patients with and without OH than in HCs. PDD patients also had significantly higher LF normalized gain when standing than patients without dementia (P = 0.015), indicating impaired dCA. LF normalized gain in standing (odds ratio: 3.756, 95% confidence interval: 1.241–11.367) and education were significantly associated with PDD.

Conclusion

Diminished dCA may represent a potential mechanism for OH and cognitive impairment and low educational level might be a significant factor contributing to the increased risk of PDD.

Diagnosis and treatment of orthostatic hypotension

Orthostatic hypotension is an unusually large decrease in blood pressure on standing that increases the risk of adverse outcomes even when asymptomatic. Improvements in haemodynamic profiling with continuous blood pressure measurements have uncovered four major subtypes: initial orthostatic hypotension, delayed blood pressure recovery, classic orthostatic hypotension, and delayed orthostatic hypotension. Clinical presentations are varied and range from cognitive slowing with hypotensive unawareness or unexplained falls to classic presyncope and syncope. Establishing whether symptoms are due to orthostatic hypotension requires careful history taking, a thorough physical examination, and supine and upright blood pressure measurements. Management and prognosis vary according to the underlying cause, with the main distinction being whether orthostatic hypotension is neurogenic or non-neurogenic. Neurogenic orthostatic hypotension might be the earliest clinical manifestation of Parkinson's disease or related synucleinopathies, and often coincides with supine hypertension. The emerging variety of clinical presentations advocates a stepwise, individualised, and primarily non-pharmacological approach to the management of orthostatic hypotension. Such an approach could include the cessation of blood pressure lowering drugs, adoption of lifestyle measures (eg, counterpressure manoeuvres), and treatment with pharmacological agents in selected cases.

Differential impact of individual autonomic domains on clinical outcomes in Parkinson's disease

INTRODUCTION

While autonomic failure is a well-known prognostic factor for more aggressive disease progression in Parkinson's disease (PD), with a three- to sevenfold higher risk of dementia and death within 10 years after the diagnosis, the individual impact of cardiovascular, gastrointestinal, urogenital, thermoregulatory, and pupillomotor autonomic domains on PD clinical outcomes remains unclear.

OBJECTIVES

We sought to determine the 5-year risk of developing dementia, falls, postural instability, dysarthria, and dysphagia in PD patients with and without autonomic impairment at baseline and to assess the joint and individual association of each autonomic domain on these key functional outcomes. In addition, we aimed to determine the impact of each autonomic domain on activities of daily living (ADLs) and health-related quality of life (HRQoL).

METHODS

We enrolled 65 consecutive PD patients in a 5-year cohort study involving standardized evaluations of autonomic symptoms, orthostatic hypotension, and motor and non-motor features, including cognitive function. Associations were estimated as odds ratio and adjusted for PD duration, age, and baseline motor impairment.

RESULTS

Cardiovascular dysautonomia was associated with a sevenfold higher risk of developing dementia (95%CI: 1.154-50.436; p = 0.035) and a fivefold higher risk of falls (95%CI: 1.099-18.949; p = 0.039), as well as significantly higher impairment in ADLs (p = 0.042) and HRQoL (p = 0.031). No relevant associations were found between the other autonomic domains and these outcomes.

CONCLUSIONS

Cardiovascular dysautonomia, but not other domains, showed an association with worse 5-year clinical outcomes in PD. Our data suggest a specific role for cardiovascular autonomic dysregulation in the pathogenic mechanisms of PD progression.

High neutrophil-to-lymphocyte ratio predicts short survival in multiple system atrophy

The neutrophil-to-lymphocyte ratio (NLR), an inflammatory marker, can predict the prognosis of neurodegenerative diseases. However, the significance of NLR for the prognosis of multiple system atrophy (MSA) has not been reported. We aimed to examine the prognostic significance of NLR in MSA. A total of 169 MSA patients and 163 matched healthy controls (HCs) were enrolled. MSA patients were divided into three groups according to the tertiles of their NLR. Kaplan–Meier survival analysis and Cox regression model were used to assessing the effect of NLR on survival. An independent validation cohort of 56 consecutive patients with probable MSA who met the inclusion criteria was included. The NLR was significantly higher in patients with MSA than that in HCs. The survival duration in patients with MSA in group 3 was shorter than that in patients in the other two groups (P = 0.013). In the multivariable Cox regression model, a higher NLR increased the risk of mortality in patients with MSA after adjusting for confounding factors (HR = 1.922, P = 0.035). Additionally, a higher NLR increased the risk of mortality in MSA with predominant cerebellar ataxia (MSA-C) (HR = 2.398, P = 0.033) and in men (HR = 3.483, P = 0.027). The concordance index for the multivariate Cox regression model was more than 0.7 both in the primary cohort and external validation cohort. Patients with MSA had a higher NLR than did HCs. A high NLR increased the risk of mortality with MSA, especially in MSA-C and in men.

Burden of caregiving for cardiovascular dysautonomia in Parkinson's disease

PURPOSE

We sought to estimate the impact of cardiovascular autonomic neuropathy (cAN) on informal caregivers of patients with Parkinson's disease (PD), defined as individuals providing regular care to a friend, partner, or family member with PD, and to evaluate the mutual relationship between caregiver burden and patient health-related quality of life (HRQoL).

METHODS

We enrolled 36 consecutive patients with PD and their informal caregivers. Patients underwent a detailed motor, autonomic, cognitive, and functional assessment. Caregivers were assessed using the Zarit Burden Interview (ZBI). Differences in caregiver burden, expressed by the ZBI score, and strength of association between caregiver burden, cAN, and HRQoL were assessed using analysis of covariance (ANCOVA), logistic regression, and linear regression analyses. Analyses were adjusted for patients' age, PD duration, and motor and cognitive disability, as well as caregivers' age.

RESULTS

Moderate-severe caregiver burden was reported in 41.7% of PDcAN⁺ versus 8.7% of PDcAN^- (p < 0.001). The ZBI score was increased in PDcAN⁺ versus PDcAN^- (31.5 ± 3.4 versus 15.2 ± 2.3; p < 0.001), with tenfold higher odds (p = 0.012) of moderate-severe caregiver burden in PDcAN⁺, even after adjusting for potential confounders. The ZBI score correlated with cAN severity (p = 0.005), global autonomic impairment (p = 0.012), and HRQoL impairment (p < 0.001).

CONCLUSION

These results highlight the significant impact of cAN on PD caregivers and the need for targeted interventions addressing this frequently overlooked and insufficiently treated source of nonmotor disability in PD.

Rasagiline does not exacerbate autonomic blood pressure dysregulation in early or mild Parkinson’s disease

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Blood pressure dysregulation is important in Parkinson’s disease.

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Anti-Parkinsonian drugs that have less effect on blood pressure should be used.

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Some monoamine oxidase B inhibitor may cause orthostatic hypotension.

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Rasagiline does not exacerbate orthostatic hypotension and nocturnal blood pressure.

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Rasagiline is a suitable medication for early or mild Parkinson's disease.

Introduction

Orthostatic hypotension (OH) and abnormal blood pressure (BP) fluctuations occur mainly due to noradrenergic dysfunction and are clinically important in patients with Parkinson’s disease (PD). They lead to impairments of cognition function, daily activities, and quality of life. Some monoamine oxidase (MAO)-B inhibitors have a sympathomimetic amine, which can be attributed to OH. Therefore, we determined whether rasagiline, a common MAO-B inhibitor used in PD treatment, can contribute to cardiovascular autonomic BP dysregulation in patients with early or mild PD.

Methods

Nineteen patients with early or mild PD were recruited, and tilt test and 24-h ambulatory BP monitoring (ABPM) were performed before and after rasagiline administration. Early or mild PD was defined as patients with de novo (n = 4), levodopa (n = 10), dopamine agonist (n = 1), levodopa and one dopamine agonist (n = 2), levodopa and droxidopa (n = 1), and levodopa and istradefylline (n = 1). Furthermore, patients with motor fluctuation and multiple dopamine agonists were excluded from our study.

Results

OH and BP frequency were not significantly exacerbated before or after rasagiline administration. No significant differences of type in BP fluctuation on ABPM and the degree of nocturnal BP falls were found before and after rasagiline administration. The Unified Parkinson’s Disease Rating Scale motor score in patients (post-rasagiline administration) was significantly improved compared with before.

Conclusion

Rasagiline seems to be a suitable medication for Parkinsonian symptoms in patients with early and mild PD. It does not exacerbate cardiovascular autonomic responses, circadian rhythm of BP, or both.

Plasma neurofilament light chain level and orthostatic hypotension in early Parkinson's disease

To delineate the impact of non-motor markers (REM sleep behavior disorder (RBD), orthostatic hypotension (OH), cardiac sympathetic denervation, hyposmia) on neuronal injury in early-stage Parkinson's disease (PD), we measured the plasma neurofilament light chain (NFL) level of PD patients and evaluated its relationship with these markers. The study population comprised a cohort of 77 patients with PD and 54 controls. OH was assessed using 5-min head-up tilt-table test. Other clinical parameters such as RBD, Unified Parkinson's Disease Rating Scale (UPDRS), cognition, Cross-Cultural Smell Identification Test (CCSIT), white matter hyperintensity (WMH), cardiac metaiodobenzylguanidine (MIBG) and striatal dopamine transporter (DAT) uptake were assessed. Plasma NFL levels were measured using Simoa platform. During mean 24.8 months of follow-up, 70 patients remained PD, 5 patients converted to Parkinson-plus syndrome (P + converter), and 2 were lost to follow-up. NFL level did not differ between PD and control groups (age-adjusted means 10.40 pg/mL vs 9.51 pg/mL, p = 0.151), but PD patients with OH (median 15.31 pg/mL) had higher levels compared with those without OH (median 9.2 pg/mL, p = 0.008), as well as the control group (median 9.7 pg/mL, p = 0.002). P + converter group had the highest plasma NFL level (38.17 pg/mL, p < 0.001). In a multiple regression analysis, OH, age, and disease duration independently correlated with plasma NFL level. This finding adds biomarker-based evidence for poor clinical outcomes associated with OH in patients with PD.

Paradoxical Cerebral Perfusion in Parkinson's Disease Patients with Orthostatic Hypotension: A Dual-Phase 18F-Florbetaben Positron Emission Tomography Study

BACKGROUND

Orthostatic hypotension (OH) may antedate Parkinson's disease (PD) or be found in early stages of the disease. OH may induce a PD brain to chronic hypotensive insults. 18F-Florbetaben (18F-FBB) tracer has a high first-pass influx rate and can be used with positron emission tomography (PET) as a surrogate marker for early- and late-phase evaluation of cerebral perfusion and cerebral amyloidosis, respectively.

OBJECTIVE

In this study, we evaluated whether 18F-FBB uptake in the early- and late-phases of PD was related to OH. This study manipulated the imaging modality to illustrate the physiology of cerebral flow with OH in PD (PD + OH).

METHODS

A group of 73 early-stage PD patients was evaluated with a head-up tilt-test and 18F-FBB PET imaging. The cognitive status was assessed by a comprehensive battery of neuropsychological tests. PET images were normalized, and both early- and late-phase standardized uptake value ratios (SUVRs) of pre-specified regions were obtained. The associations between regional SUVRs and OH and cognitive status were analyzed.

RESULTS

Twenty (27.4%) participants had OH. Thirteen (17.8%) patients were interpreted as having amyloid pathology based on regional 18F-FBB uptake. Early-phase SUVRs were higher in specific brain regions of PD + OH patients than those without OH. However, late-phase SUVRs did not differ between the groups. The early-phase SUVRs were not influenced by amyloid burden or by interaction between amyloid and orthostatic hypotension. Cognitive functions were not disparate when PD + OH patients were contrasted with non-OH patients in this study.

CONCLUSION

Cerebral blood flow was elevated in patients with early PD + OH. This finding suggests augmented cerebral perfusion in PD + OH might be a compensatory regulation in response to chronic OH.

Autonomic Function in Patients With Parkinson's Disease: From Rest to Exercise

Parkinson’s disease (PD) is a common neurodegenerative disorder classically characterized by symptoms of motor impairment (e.g., tremor and rigidity), but also presenting with important non-motor impairments. There is evidence for the reduced activity of both the parasympathetic and sympathetic limbs of the autonomic nervous system at rest in PD. Moreover, inappropriate autonomic adjustments accompany exercise, which can lead to inadequate hemodynamic responses, the failure to match the metabolic demands of working skeletal muscle and exercise intolerance. The underlying mechanisms remain unclear, but relevant alterations in several discrete central regions (e.g., dorsal motor nucleus of the vagus nerve, intermediolateral cell column) have been identified. Herein, we critically evaluate the clinically significant and complex associations between the autonomic dysfunction, fatigue and exercise capacity in PD.

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.

Baroreflex dysfunction in Parkinson's disease: integration of central and peripheral mechanisms

The incidence of Parkinson's disease (PD) is increasing worldwide. Although the PD hallmark is the motor impairments, nonmotor dysfunctions are now becoming more recognized. Recently, studies have suggested that baroreflex dysfunction is one of the underlying mechanisms of cardiovascular dysregulation observed in patients with PD. However, the large body of literature on baroreflex function in PD is unclear. The baroreflex system plays a major role in the autonomic, and ultimately blood pressure and heart rate, adjustments that accompany acute cardiovascular stressors on a daily basis. Therefore, impaired baroreflex function (i.e., decreased sensitivity or gain) can lead to altered neural cardiovascular responses. Since PD affects parasympathetic and sympathetic branches of the autonomic nervous system and both are orchestrated by the baroreflex system, understanding of this crucial mechanism in PD is necessary. In the present review, we summarize the potential altered central and peripheral mechanisms affecting the feedback-controlled loops that comprise the reflex arc in patients with PD. Major factors including arterial stiffness, reduced number of C1 and activation of non-C1 neurons, presence of central α-synuclein aggregation, cardiac sympathetic denervation, attenuated muscle sympathetic nerve activity, and lower norepinephrine release could compromise baroreflex function in PD. Results from patients with PD and from animal models of PD provide the reader with a clearer picture of baroreflex function in this clinical condition. By doing so, our intent is to stimulate future studies to evaluate several unanswered questions in this research area.

Interrelationships between Survival, Sex, and Blood Pressure in Patients with Multiple System Atrophy

OBJECTIVE

The aim of this study is to estimate survival among patients with multiple system atrophy-parkinsonian type (MSA-P) or cerebellar type MSA (MSA-C) in relation to blood pressure (BP) measurements, by sex.

METHODS

A cohort of 99 MSA patients was studied retrospectively. Their BP measurements were obtained during prolonged (40 min, vertical position) drug-free tilt testing. We used K-M survival curves and Cox regression to calculate adjusted (to age of onset) hazard ratios (HRs) of BP measurements on time to death by MSA subtype and sex.

RESULTS

Fifty-two MSA patients were males and 47 were females. Sixty-three of them had MSA-P and 36 had MSA-C. The mean age at motor symptom onset was 61.1 ± 10.4 years, and mean disease duration at the time of BP assessment was 8.0 ± 4.7 years. The 2 study groups (MSA-P and MSA-C) did not differ significantly in age at MSA onset, sex ratio, or disease duration. Survival time did not differ between the groups {medians: 12 years (95% confidence interval [CI]: 8-28) and 10 years (95% CI: 8-13), respectively}. The MSA-P group showed a trend towards better survival for males (log-rank p = 0.0925). The maximal diastolic orthostatic BP decline during tilt testing had a borderline positive association with death risk among MSA-C males (adjusted HR = 1.18, p = 0.0665), and systolic BP after 10 min in a supine position had a significant positive association with death risk among MSA-P males (adjusted HR = 1.06, p = 0.0354).

CONCLUSIONS

The findings of a sex-based difference in the effect of BP on death risk may be important for adjusting the therapeutic approach to MSA patients.

Dopaminergic Correlates of Orthostatic Hypotension in de novo Parkinson's Disease

BACKGROUND

Orthostatic hypotension (OH) at an early stage of Parkinson's disease (PD) predicts poor prognosis, which may suggest degeneration of dopaminergic neurons affects sympathetic function, causing OH.

OBJECTIVE

We tested the hypothesis that striatal dopaminergic depletion is associated with OH in PD.

METHODS

Out of 99 patients with newly diagnosed untreated PD, 81 patients were enrolled according to our selection criteria. All patients underwent head-up tilt-table testing and striatal 123I-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (123I-FP-CIT) dopamine transporter single photon emission computed tomography (DAT-SPECT). DaTQUANT software (GE Healthcare) was used as a semi-quantitative tool to analyze DAT-SPECT data. The association between hemodynamic changes and 123I-FP-CIT uptake was examined.

RESULTS

123I-FP-CIT uptake in the putamen, especially the anterior part and left side, was related not only to motor severity but also to OH. Change in systolic blood pressure correlated negatively with 123I-FP-CIT uptake in bilateral anterior putamen (left: p < 0.01, right: p < 0.05) and left posterior putamen (p < 0.05). Patients with OH had more severe dopamine depletion in left anterior (p = 0.008) and posterior (p = 0.007) putamen at a similar motor severity than did patients without OH even though both groups have similar baseline characteristics. An analysis of asymmetry index showed patients with OH had symmetrically decreased dopamine levels in anterior putamen when compared to those without OH (p = 0.024).

CONCLUSION

OH is closely related to striatal dopamine depletion in PD. This relation may help to account for the prognostic value of OH.

Management of Orthostatic Hypotension

PURPOSE OF REVIEW

This article reviews the management of orthostatic hypotension with emphasis on neurogenic orthostatic hypotension.

RECENT FINDINGS

Establishing whether the cause of orthostatic hypotension is a pathologic lesion in sympathetic neurons (ie, neurogenic orthostatic hypotension) or secondary to other medical causes (ie, non-neurogenic orthostatic hypotension) can be achieved by measuring blood pressure and heart rate at the bedside. Whereas fludrocortisone has been extensively used as first-line treatment in the past, it is associated with adverse events including renal and cardiac failure and increased risk of all-cause hospitalization. Distinguishing whether neurogenic orthostatic hypotension is caused by central or peripheral dysfunction has therapeutic implications. Patients with peripheral sympathetic denervation respond better to norepinephrine agonists/precursors such as droxidopa, whereas patients with central autonomic dysfunction respond better to norepinephrine reuptake inhibitors.

SUMMARY

Management of orthostatic hypotension is aimed at improving quality of life and reducing symptoms rather than at normalizing blood pressure. Nonpharmacologic measures are the key to success. Pharmacologic options include volume expansion with fludrocortisone and sympathetic enhancement with midodrine, droxidopa, and norepinephrine reuptake inhibitors. Neurogenic supine hypertension complicates management of orthostatic hypotension and is primarily ameliorated by avoiding the supine position and sleeping with the head of the bed elevated.

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.

The absence of orthostatic heart rate increase is associated with cognitive impairment in Parkinson's disease

Orthostatic hypotension (OH) frequently accompanies autonomic dysfunction and is an important risk factor for cognitive impairment in Parkinson’s disease (PD). While OH is usually diagnosed based on an orthostatic blood pressure drop, the association between the heart rate response and cognitive impairment remains unclear. We retrospectively analyzed 143 cases of clinically diagnosed PD to determine the association between the absence of a heart rate response and cognitive impairment in PD with OH. Among the patients with OH, neurogenic OH was diagnosed in cases without a heart rate increase, while all other patients were diagnosed with non-neurogenic OH. Dementia was found in 23 of 143 PD cases (16.1%) in this cohort. The presence of OH was an independent risk factor for dementia in PD in addition to the disease severity, years of education and beta-blockers use. Neurogenic OH was significantly associated with dementia compared to the no OH group (hazard ratio [HR] 7.3, 95% confidence interval [CI] 2.2–24.6, P<0.01), an association that was preserved after adjusting for age, gender and other covariant factors. However, no such association was observed for non-neurogenic OH (HR 2.9, 95%CI 0.8–10.9, P = 0.12). While the cognitive impairment was significantly worse in the neurogenic OH group than the no-OH group, the groups were otherwise similar. The blood pressure decrease was significantly lower in both OH groups than in the no-OH group, despite no significant differences between the OH groups. Our finding showed that OH without a heart rate response was an important predictor of cognitive impairment in PD.

Comparisons of cardiovascular dysautonomia and cognitive impairment between de novo Parkinson's disease and de novo dementia with Lewy bodies

BACKGROUND

Cognitive impairment may be correlated with cardiovascular dysautonomia, including blood pressure (BP) dysregulation, in Parkinson's disease (PD), but the association between these factors in dementia with Lewy bodies (DLB) is uncertain. This study aimed to clarify whether cardiovascular dysautonomia had an influence on cognitive function in Lewy body disease or not.

METHODS

Ninty-nine patients with de novo PD (n = 75) and DLB (n = 24) were evaluated using the Mini-Mental State Examination (MMSE) and Frontal Assessment Battery (FAB). Cardiac ¹²³I-metaiodobenzylguanidine (MIBG) scintigraphy, orthostatic hypotension (OH), supine hypertension (SH), postprandial hypotension (PPH), nocturnal BP fall in 24-h ambulatory blood pressure monitoring (ABPM) and constipation were estimated. Associations of these factors with cognitive and executive dysfunction were examined.

RESULTS

In DLB, MIBG uptake was reduced and OH, PPH and SH were severely disturbed, compared to PD. The nocturnal BP fall in ABPM was lower in DLB, and the failure of nocturnal BP fall in PD was associated with MMSE, after adjustment for other clinical features. FAB was significantly associated nocturnal BP fall, age and SH in PD, but no significant correlations among factors were found for DLB.

CONCLUSION

The significant association between nocturnal BP dysregulation and cognitive or executive decline in PD might be due to impaired microvascular circulation or invasion of α-synuclein in the CNS. The lack of a correlation of BP insufficiency with cognitive impairment in DLB suggests initial involvement of Lewy body pathology in the neocortex, regardless of Lewy body invasion of the autonomic nervous system.

Clinical Trials for Neurogenic Orthostatic Hypotension: A Comprehensive Review of Endpoints, Pitfalls, and Challenges

Neurogenic orthostatic hypotension (nOH) is among the most debilitating nonmotor features of patients with Parkinson's disease (PD) and other synucleinopathies. Patients with PD and nOH generate more hospitalizations, make more emergency room visits, create more telephone calls/mails to doctors, and have earlier mortality than those with PD but without nOH. Overall, the health-related cost in patients with PD and OH is 2.5-fold higher compared with patients with PD without OH. Hence, developing effective therapies for nOH should be a research priority. In the last few decades, improved understanding of the pathophysiology of nOH has led to the identification of therapeutic targets and the development and approval of two drugs, midodrine and droxidopa. More effective and safer therapies, however, are still needed, particularly agents that could selectively increase blood pressure only in the standing position because supine hypertension is the main limitation of available drugs. Here we review the design and conduct of nOH clinical trials in patients with PD and other synucleinopathies, summarize the results of the most recently completed and ongoing trials, and discuss challenges, bottlenecks, and potential remedies.

Morbidity and mortality in orthostatic hypotension

This review summarizes the current literature on the epidemiology of orthostatic hypotension (OH) in the elderly and in patients with autonomic impairment also known as neurogenic OH (nOH); these two conditions have distinct pathophysiologies and affect different patient populations. The prevalence of OH in the elderly varies depending on the study population. In community dwellers, OH prevalence is estimated at 16%, whereas in institutionalized patients, it may be as high as 60%. The prevalence of OH increases exponentially with age, particularly in those 75 years and older. Multiple epidemiological studies have identified OH as a risk factor for all-cause mortality and cardiovascular disease including heart failure and stroke. Real-world data from administrative databases found polypharmacy, multiple co-morbid conditions, and high health-care utilization as common characteristics in OH patients. A comprehensive evaluation of medications associated with OH is discussed with particular emphasis on the use of anti-hypertensive therapy from two large clinical trials on high-intensive versus standard blood pressure management. Finally, we also review the epidemiology of nOH based on the underlying neurodegenerative disorder (either Parkinson's disease or multiple system atrophy), and the presence of co-morbid conditions such as hypertension and cognitive impairment.

Difference in cardiovascular response during orthostatic stress in Parkinson's disease and multiple system atrophy

Although orthostatic hypotension is more prominent in multiple system atrophy (MSA) than in Parkinson's disease (PD), there is no study comparing the degree of decrease in total peripheral resistance and cardiac response during orthostatic stress between both diseases. In this study, we examined whether there is a difference in cardiovascular response between MSA and PD. We examined the results of the head-up tilt test in 68 patients with MSA, 28 patients with cardiac non-denervated PD, and 70 patients with cardiac denervated PD whose total peripheral resistance after 60° tilting was lower than the value at 0°. Differences in cardiac output and blood pressure changes were compared against the decrease in total peripheral resistance. There was no difference in the degree of decrease in total peripheral resistance among the three groups. However, the slope of the regression line revealed that the increase in cardiac output against the change in total peripheral resistance was significantly lower in the MSA group than in the cardiac non-denervated and denervated PD groups, and that the decrease in systolic blood pressure against the change in total peripheral resistance was significantly greater in the MSA group than in the cardiac non-denervated and denervated PD groups. In MSA, the cardiac response during orthostatic stress is lower than that in PD, possibly underlying the fact that orthostatic hypotension is more prominent in MSA than in PD.

Biofluid Markers for Prodromal Parkinson's Disease: Evidence From a Catecholaminergic Perspective

Parkinson's disease (PD) is the most frequent of all Lewy body diseases, a family of progressive neurodegenerative disorders characterized by intra-neuronal cytoplasmic inclusions of α-synuclein. Its most defining features are bradykinesia, tremor, rigidity and postural instability. By the time PD manifests with motor signs, 70% of dopaminergic midbrain neurons are lost, and the disease is already in the middle or late stage. However, there are various non-motor symptoms occurring up to 20 years before the actual parkinsonism that are closely associated with profound deficiency of myocardial noradrenaline content and peripheral sympathetic denervation, as evidenced by neuroimaging experiments in recent years. Additionally, there is an inherent autotoxicity of catecholamines in the neuronal cells in which they are produced, forming toxic catecholaldehyde intermediates that make α-synuclein prone to aggregation, initiating a cascade of events that ultimately leads to neuronal death. The etiopathogenesis of PD and related synucleinopathies thus may well be a prototypical example of a catecholamine-regulated neurodegeneration, given that the synucleinopathy in PD spreads in synergy with central and peripheral catecholaminergic dysfunction from the earliest phases onward. That is why catecholamines and their metabolites, precursors, or derivatives in cerebrospinal fluid or plasma could be of particular interest as biomarkers for prodromal and de novo PD. Because there is great demand for such markers, this mini-review summarizes all catecholamine-related studies to date, in addition to providing profound neurochemical evidence on a systemic and cellular level to further emphasize this hypothesis and with emphasis on extracellular vesicles as a novel diagnostic and therapeutic incentive.

Early autonomic and cognitive dysfunction in PD, DLB and MSA: blurring the boundaries between α-synucleinopathies

Differential diagnosis between Parkinson's disease, dementia with Lewy bodies and multiple system atrophy can be difficult, especially because in early phase they might present with overlapping clinical features. Notably, orthostatic hypotension and cognitive dysfunction are common nonmotor aspects of parkinsonian syndromes and can be both present from the earliest stages of all α-synucleinopathies, indicating a common neurobiological basis in their strong relationship. In view of the increasing awareness about the prevalence of mild cognitive dysfunction in multiple system atrophy, the relevance of autonomic dysfunction in demented parkinsonian patients, the critical role of non-motor symptoms in clustering Parkinson's disease patients and the shift to studying patients in the prodromal phase, we will discuss some intrinsic limitations of current clinical diagnostic criteria, even when applied by movement disorder specialists. In particular, we will focus on the early coexistence of autonomic and cognitive dysfunction in the setting of overt or latent parkinsonism as pitfalls in the differential diagnosis of α-synucleinopathies. As early and accurate diagnosis remains of outmost importance for counselling of patients and timely enrolment into disease-modifying clinical trials, a continuous effort of research community is ongoing to further improve the clinical diagnostic accuracy of α-synucleinopathies.

The impact of supine hypertension on target organ damage and survival in patients with synucleinopathies and neurogenic orthostatic hypotension

INTRODUCTION

In addition to neurogenic orthostatic hypotension (nOH), patients with synucleinopathies frequently have hypertension when supine. The long-term consequences of both abnormalities are difficult to disentangle. We aimed to determine if supine hypertension is associated with target organ damage and worse survival in patients with nOH.

METHODS

Patients with nOH due to multiple system atrophy (MSA), Parkinson disease (PD), or pure autonomic failure (PAF) were classified into those with or without supine hypertension (systolic BP of at least 140 mmHg or diastolic BP of at least 90 mmHg). Organ damage was assessed by measuring cerebral white matter hyperintensities (WMH), left ventricular hypertrophy (LVH), and renal function. We prospectively followed patients for 30 months (range: 12-66 months) and recorded incident cardiovascular events and all-cause mortality.

RESULTS

Fifty-seven patients (35 with probable MSA, 14 with PD and 8 with PAF) completed all evaluations. In addition to nOH (average fall 35 ± 21/17 ± 14 mmHg, systolic/diastolic, mean ± SD), 38 patients (67%) had supine hypertension (systolic BP > 140 mmHg). Compared to those without hypertension, patients with hypertension had higher blood urea nitrogen levels (P = 0.005), lower estimated glomerular filtration rate (P = 0.008), higher prevalence of LVH (P = 0.040), and higher WMH volume (P = 0.019). Longitudinal follow-up of patients for over 2 years (27.1 ± 14.5 months) showed that supine hypertension was independently associated with earlier incidence of cardiovascular events and death (HR = 0.25; P = 0.039).

CONCLUSIONS

Supine hypertension in patients with nOH was associated with an increased risk for target organ damage, cardiovascular events, and premature death. Defining management strategies and safe blood pressure ranges in patients with nOH remains an important research question.

Cardiovascular Safety Considerations in the Treatment of Neurogenic Orthostatic Hypotension

Neurogenic orthostatic hypotension (nOH), a drop in blood pressure upon standing resulting from autonomic malfunction, may cause debilitating symptoms that can affect independence in daily activities and quality-of-life. nOH may also be associated with cardiovascular comorbidities (e.g., supine hypertension, heart failure, diabetes, and arrhythmias), making treatment decisions complicated and requiring management that should be based on a patient's cardiovascular profile. Additionally, drugs used to treat the cardiovascular disorders (e.g., vasodilators, β-blockers) can exacerbate nOH and concomitant symptoms. When orthostatic symptoms are severe and not effectively managed with nonpharmacologic strategies (e.g., water ingestion, abdominal compression), droxidopa or midodrine may be effective. Droxidopa may be less likely than midodrine to exacerbate supine hypertension, based on conclusions of a limited meta-analysis. In conclusion, treating nOH in patients with cardiovascular conditions requires a balance between symptom relief and minimizing adverse outcomes.

Association of orthostatic blood pressure with the symptoms of orthostatic hypotension and cognitive impairment in patients with multiple system atrophy

The degree and frequency of orthostatic hypotension (OH) are high in patients with multiple system atrophy (MSA); however, the association of orthostatic blood pressure (BP) with the symptoms of OH and cognitive impairment in these patients remains unclear. The aim of this study was to clarify whether absolute BP and/or changes in BP during standing are related to OH symptoms and cognitive impairment in patients with MSA. Thirty-two patients with MSA were examined using the head-up tilt and cognitive function tests. OH symptoms were evaluated using a patient-reported scale. The results were compared with those for 15 age- and sex-matched healthy controls. Seventeen of the 32 (53.1%) patients had OH, with eight of them exhibiting OH symptoms, which were related to the absolute BP value at 60° tilt. However, OH symptoms were not related to the degree of decrease in BP during the tilt test, and they were frequently observed in patients with a mean BP of <80 mmHg at 60° tilt (sensitivity, 67%; specificity, 91%). Cognitive dysfunction assessed by the Mini-Mental State Examination (MMSE; ≤ 26) was also associated with a low mean BP at 60° tilt (odds ratio, 1.32; 95% confidence interval, 1.04-1.67; p = 0.02). The upright BP value is associated with OH symptoms and the MMSE score in patients with MSA. Thus, careful observation of OH symptoms can enable early management of BP and the detection of cognitive impairment in these patients.

Disease progression and prognostic factors in multiple system atrophy: A prospective cohort study

Multiple system atrophy (MSA) is a rare neurodegenerative disease, with limited understanding of disease progression and prognostic factors. We leveraged the data of a large prospective cohort of MSA to study both clinical progression and survival and assess their determinants. All consecutive patients seen at the French Reference Centre for MSA since 2007 were included in a prospective cohort with an annual follow-up including the Unified MSA Rating Scale (UMSARS). We used joint models to evaluate the risk of death, the mean trajectory of each UMSARS subscale and to determine the potential factors. Investigated factors included gender, age at baseline, MSA subtype, diagnosis certainty, type of first symptoms and the duration between symptom onset and the first visit. Among the 261 MSA patients included in our cohort, the median duration of clinical follow-up was 2.1 years (up to 10.3 years) and the median survival was 4.0 years since the first visit. Main factors for poor survival were the progression over time of UMSARS score (I + II and IV) and the severity of orthostatic hypotension. MSA subtype had no effect on progression or survival. The UMSARS I + II score progressed faster over time in subjects with autonomic dysfunction as the initial feature and in women. Despite a faster progression, women and men had similar survival. From this large MSA cohort, we confirm the rapid progression and poor prognosis of MSA. We provide additional evidence for a negative impact of early autonomic dysfunction and the severity of orthostatic hypotension on both disease progression and survival.

Phosphorylated Alpha-Synuclein in Red Blood Cells as a Potential Diagnostic Biomarker for Multiple System Atrophy: A Pilot Study

Diagnosis of multiple system atrophy (MSA) remains a challenge, due to the complexity and overlapping of its symptoms with other Parkinsonian disorders. The critical role of alpha-synuclein (α-syn) in the pathogenesis of MSA makes it an ideal biomarker for the diagnosis of MSA. Although α-syn alterations in cerebrospinal fluid (CSF) and blood plasma have been extensively assessed for the utility in diagnosing MSA, inconsistent results have been obtained, presumably due to the contamination by hemolysis and other confounding factors. In this study, levels of serine 129-phosphorylated α-syn (pS-α-syn), a major pathologic form of α-syn, in red blood cells (RBCs), were measured using ELISA in a Chinese cohort consisting of 107 MSA patients and 220 healthy controls. A significant increase in the levels of pS-α-syn in RBCs (pS-α-syn-RBC) was observed in MSA patients than in healthy controls (14.02 ± 4.02 ng/mg versus 11.89 ± 3.57 ng/mg; p < 0.0001). Receiver operating characteristic curve (ROC) indicated that pS-α-syn-RBC discriminated the patients well from the controls with a sensitivity of 80.37% (95% confidence interval (CI): 71.58%-87.42%), a specificity of 88.64% (95% CI: 83.68%-92.51%), and an area under the curve (AUC) of 0.91 (95% CI: 0.87-0.94). The levels of pS-α-syn-RBC were negatively correlated with RBD-HK scores and differed between MSA-P and MSA-C subtypes (13.27 ± 1.91 versus 12.19 ± 3.04; p=0.025). The difference between subtypes was seen at Hoehn and Yahr stages 3 and 4, and the age at onset (AAO) between 60 and 69 years (p=0.016). The results suggest that pS-α-syn-RBC is increased in MSA patients and can be used as a potential diagnostic biomarker for MSA.

Impact of orthostatic hypotension on wheelchair use in patients with Parkinson's disease

Wheelchair use is an important indicator of disease progression in Parkinson's disease (PD). Here, we investigated whether orthostatic hypotension (OH) affects the time to wheelchair use. We examined 33 PD patients with OH and 95 without OH. Median time to start using a wheelchair calculated from the time of disease onset was significantly shorter in patients with OH than in those without OH (12.0 vs 19.0 years; p < 0.001). Thus, appropriate management of OH and motor function is necessary.

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).

Orthostatic hypotension and REM sleep behaviour disorder: impact on clinical outcomes in α-synucleinopathies

OBJECTIVE

Review the effect of orthostatic hypotension (OH) and rapid-eye-movement sleep behavioural disorder (RBD) on survival, cognitive impairment and postural stability, and discuss pathogenic mechanisms involved in the association of these two common non-motor features with relevant clinical outcomes in α-synucleinopathies.

METHODS

We searched PubMed (January 2007-February 2019) for human studies of OH and RBD evaluating cognitive impairment, postural instability, and survival in Parkinson's disease (PD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA) and pure autonomic failure (PAF). Included studies were analysed for design, key results and limitations as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

OH and RBD showed a positive association with cognitive impairment in PD and DLB, conflicting association in PAF, and no association in MSA. OH was correlated with incident falls and postural instability in PD and DLB but not in MSA. The association between RBD and postural instability was inconclusive; positive in five studies, negative in seven. OH, but not RBD, correlated with reduced survival in PD, DLB and MSA. The combination of OH and RBD was associated with cognitive impairment and more rapid progression of postural instability.

CONCLUSIONS

OH and RBD yielded individual and combined negative effects on disability in α-synucleinopathies, reflecting a 'malignant' phenotype of PD with early cognitive impairment and postural instability. Underlying mechanisms may include involvement of selected brainstem cholinergic and noradrenergic nuclei.

Association of innervation-adjusted alpha-synuclein in arrector pili muscles with cardiac noradrenergic deficiency in autonomic synucleinopathies

BACKGROUND

Autonomic synucleinopathies feature deposition of the protein alpha-synuclein (AS) in neurons [e.g., Lewy body neurogenic orthostatic hypotension (nOH)] or glial cells (multiple system atrophy, MSA). AS in skin biopsies might provide biomarkers of these diseases; however, this approach would be complicated or invalidated if there were substantial loss of AS-containing nerves. We report AS content in arrector pili muscles in skin biopsies after adjustment for local innervation in patients with Lewy body nOH or MSA. Cardiac sympathetic neuroimaging by myocardial ¹⁸F-dopamine positron emission tomography (PET) was done to examine pathophysiological correlates of innervation-adjusted AS.

METHODS

Thirty-one patients (19 Lewy body nOH, 12 MSA) underwent thoracic ¹⁸F-dopamine PET and skin biopsies. AS signal intensity analyzed by immunofluorescence microscopy was adjusted for innervation by the ratio of AS to protein gene product (PGP) 9.5, a pan-axonal marker (Harvard lab site), or the ratio of AS to tyrosine hydroxylase (TH), an indicator of catecholaminergic neurons (NIH lab site).

RESULTS

The Lewy body nOH group had higher ratios of AS/PGP 9.5 or log AS/TH than did the MSA group (0.89 ± 0.05 vs. 0.66 ± 0.04, -0.13 ± 0.05 vs. -1.60 ± 0.33; p < 0.00001 each). All 19 Lewy body patients had AS/PGP 9.5 > 0.8 or log AS/TH > 1.2 and had myocardial ¹⁸F-dopamine-derived radioactivity < 6000 nCi-kg/cc-mCi, the lower limit of normal. Two MSA patients (17%) had increased AS/PGP or log AS/TH, and two (17%) had low ¹⁸F-dopamine-derived radioactivity.

CONCLUSIONS

Lewy body forms of nOH are associated with increased innervation-adjusted AS in arrector pili muscles and neuroimaging evidence of myocardial noradrenergic deficiency.

Pure Autonomic Failure

Pure autonomic failure (PAF) is a neurodegenerative disorder of the autonomic nervous system clinically characterized by orthostatic hypotension. The disorder has also been known as Bradbury-Eggleston syndrome, named for the authors of the 1925 seminal description. Patients typically present in midlife or later with orthostatic hypotension or syncope. Autonomic failure may also manifest as genitourinary, bowel, and thermoregulatory dysfunction. With widespread involvement, patients may present to a variety of different specialties and require multidisciplinary treatment approaches. Pathologically, PAF is characterized by predominantly peripheral deposition of α-synuclein. However, patients with PAF may progress into other synucleinopathies with central nervous system involvement.

Orthostatic hypotension in Parkinson disease: A 7-year prospective population-based study

OBJECTIVE

To determine the frequency, evolution, and associated features of orthostatic hypotension (OH) over 7 years of prospective follow-up in a population-based, initially drug-naive Parkinson disease (PD) cohort.

METHODS

We performed repeated lying and standing blood pressure measurements in 185 patients with newly diagnosed PD and 172 matched normal controls to determine the occurrence of (1) OH using consensus-based criteria and (2) clinically significant OH (mean arterial pressure in standing position ≤75 mm Hg). We applied generalized estimating equations models for correlated data to investigate associated features of these 2 outcomes in patients with PD.

RESULTS

OH was more common in patients with PD than controls at all visits, with the relative risk increasing from 3.0 (95% confidence interval [CI] 1.6-5.8; p < 0.001) at baseline to 4.9 (95% CI 2.4-10.1; p < 0.001) after 7 years. Despite a high cumulative prevalence of OH (65.4%) and clinically significant OH (29.2%), use of antihypotensive drugs was very rare (0.5%). OH was independently associated with older age (odds ratio [OR] 1.06 per year; 95% CI 1.03-1.10), lower Mini-Mental State Examination score (OR 0.91 [0.85-0.97] per unit), and longer follow-up time (OR 1.12 [1.03-1.23] per year). Clinically significant OH was associated with the same characteristics, in addition to higher levodopa equivalent dosage (OR 1.16 [1.07-1.25] per 100 mg).

CONCLUSIONS

In this population-based study, we found OH to be a very frequent but undertreated complication in early PD, with associations to both disease-specific symptoms and drug treatment. Our findings suggest that clinicians should more actively assess and manage OH abnormalities in PD.

Computational modeling reveals multiple abnormalities of myocardial noradrenergic function in Lewy body diseases

BACKGROUND

Lewy body diseases, a family of aging-related neurodegenerative disorders, entail loss of the catecholamine dopamine in the nigrostriatal system and equally severe deficiency of the closely related catecholamine norepinephrine in the heart. The myocardial noradrenergic lesion is associated with major non-motor symptoms and decreased survival. Numerous mechanisms determine norepinephrine stores, and which of these are altered in Lewy body diseases has not been examined in an integrated way. We used a computational modeling approach to assess comprehensively pathways of cardiac norepinephrine synthesis, storage, release, reuptake, and metabolism in Lewy body diseases. Application of a novel kinetic model identified a pattern of dysfunctional steps contributing to norepinephrine deficiency. We then tested predictions from the model in a new cohort of Parkinson disease patients.

METHODS

Rate constants were calculated for 17 reactions determining intra-neuronal norepinephrine stores. Model predictions were tested by measuring post-mortem apical ventricular concentrations and concentration ratios of catechols in controls and patients with Parkinson disease.

RESULTS

The model identified low rate constants for three types of processes in the Lewy body group-catecholamine biosynthesis via tyrosine hydroxylase and L-aromatic-amino-acid decarboxylase, vesicular storage of dopamine and norepinephrine, and neuronal norepinephrine reuptake via the cell membrane norepinephrine transporter. Post-mortem catechols and catechol ratios confirmed this triad of model-predicted functional abnormalities.

CONCLUSION

Denervation-independent impairments of neurotransmitter biosynthesis, vesicular sequestration, and norepinephrine recycling contribute to the myocardial norepinephrine deficiency attending Lewy body diseases. A proportion of cardiac sympathetic nerves are "sick but not dead," suggesting targeted disease-modification strategies might retard clinical progression.

TRIAL REGISTRATION

This study was not a clinical trial.

FUNDING

The research reported here was supported by the Division of Intramural Research, NINDS.