Diagnosis and treatment of supine hypertension in autonomic failure patients with orthostatic hypotension

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.

Association of Diabetes with Changes in Blood Pressure during Hemodialysis: A Secondary Analysis of the Frequent Hemodialysis Network Daily Trial

INTRODUCTION

Diabetes mellitus is a common cause of kidney failure and is often complicated by autonomic neuropathy, which may have implications for blood pressure (BP) homeostasis during hemodialysis (HD).

METHODS

In this post hoc analysis of the Frequent Hemodialysis Network (FHN) Daily Trial, we used random effects Poisson and linear regression models to estimate the association of diabetes (vs. not) with intra-dialytic hypotension (IDH) and peri-dialytic BP parameters, respectively. We tested for differential associations according to the randomized treatment (6/week vs. 3/week HD) and pre-HD systolic BP.

RESULTS

Of the 244 patients with intra-dialytic BP data, 100 (41%) had diabetes at baseline. The mean age was 51 ± 14 years; overall, 39% were female. In adjusted models, diabetes (vs. not) was associated with a 93% higher risk of developing IDH (IRR: 1.93; 95% CI: 1.26, 2.95). There was no evidence that the randomized treatment assignment modified the association between diabetes and IDH (pinteraction = 0.32), but more potent associations were noted among those with higher pre-HD systolic BP (pinteraction < 0.001). Diabetes (vs. not) was associated with a lower adjusted nadir intra-HD BP (-4.2; 95% CI: -8.3, -0.2 mm Hg) but not with the pre- or post-HD systolic BP.

CONCLUSIONS

Among participants of the FHN Daily Trial, patients with diabetes had a higher risk of IDH and lower nadir intra-HD systolic BP than patients without diabetes, even when undergoing HD up to 6 times per week.

A therapeutic challenge relating to the association of orthostatic hypotension and supine hypertension in a patient with cardiac autonomic neuropathy: a case report

BACKGROUND

Cardiac autonomic neuropathy is a highly prevalent pathology in the diabetic population, and is the leading cause of death in this population. Orthostatic hypotension is the main clinical manifestation of the disease. In some patients, this orthostatic hypotension is associated with supine hypertension, posing a therapeutic challenge since treatment of one entity may aggravate the other. The challenge is to manage each of these two hemodynamic opposites without exposing the patient to a life-threatening risk of severe hypotension or hypertension.

CASE PRESENTATION

We report a case of a 62-year-old ethnic Moroccan woman who has cardiovascular risk factors such as type 2 diabetes, arterial hypertension, and dyslipidemia. The patient's symptoms included dizziness, tremors, morning sickness, palpitations, and intolerance to exertion. Given her symptomatology, the patient benefited from an exploration of the autonomic nervous system through cardiovascular reactivity tests (Ewing tests), which confirmed the diagnosis of cardiac autonomic neuropathy. In addition to orthostatic hypotension, our patient had supine arterial hypertension, complicating management. To treat orthostatic hypotension, we advised the patient to avoid the supine position during the day, to raise the head of the bed during the night, and to have a sufficient fluid intake, with a gradual transition from decubitus to orthostatism and venous restraint of the lower limbs. Supine hypertension was treated with transdermal nitrates placed at bedtime and removed 1 hour before getting up. One week after the introduction of treatment, the patient reported a clear regression of functional symptoms, with an improvement in her quality of life. Improvement in symptomatology was maintained during quarterly follow-up consultations.

CONCLUSIONS

Cardiac autonomic neuropathy is a very common pathology in diabetic patients. It is a serious condition with a life-threatening prognosis. Its management must be individualized according to the symptomatology and profile of each patient. The treatment of patients with orthostatic hypotension and supine hypertension requires special attention to ensure that each entity is treated without aggravating the other.

Orthostatic Hypotension in Hypertensive Adults: Harry Goldblatt Award for Early Career Investigators 2021

Orthostatic hypotension affects roughly 10% of individuals with hypertension and is associated with several adverse health outcomes, including dementia, cardiovascular disease, stroke, and death. Among adults with hypertension, orthostatic hypotension has also been shown to predict patterns of blood pressure dysregulation that may not be appreciated in the office setting, including nocturnal nondipping. Individuals with uncontrolled hypertension are at particular risk of orthostatic hypotension and may meet diagnostic criteria for the condition with a smaller relative reduction in blood pressure compared with normotensive individuals. Antihypertensive medications are commonly de-prescribed to address orthostatic hypotension; however, this approach may worsen supine or seated hypertension, which may be an important driver of adverse events in this population. There is significant variability between guidelines for the diagnosis of orthostatic hypotension with regards to timing and position of blood pressure measurements. Clinically relevant orthostatic hypotension may be missed when standing measurements are delayed or when taken after a seated rather than supine position. The treatment of orthostatic hypotension in patients with hypertension poses a significant management challenge for clinicians; however, recent evidence suggests that intensive blood pressure control may reduce the risk of orthostatic hypotension. A detailed characterization of blood pressure variability is essential to tailoring a treatment plan and can be accomplished using both in-office and out-of-office monitoring.

Advances in the Pathophysiology and Management of Supine Hypertension in Patients with Neurogenic Orthostatic Hypotension

PURPOSE OF REVIEW

Patients with neurogenic orthostatic hypotension (OH) frequently have hypertension in the supine position (sHTN). We review the controversies surrounding the need and safety of treating sHTN in patients with OH.

RECENT FINDINGS

The presence of sHTN complicates the management of OH because treatment of one can worsen the other. New approaches have been developed to treat OH without worsening sHTN by preferentially improving standing blood pressure, such as medications that harness the patient's residual sympathetic tone like pyridostigmine and atomoxetine, and devices such as an automated abdominal binder that targets the inappropriate splanchnic venous pooling causing OH. There is a reluctance to treat sHTN for fear of increasing the risks of falls and syncope associated with OH, thought to be more immediate and dangerous than the late complications of organ damage associated with sHTN. This, however, does not take into account that nighttime sHTN induces natriuresis, volume loss, and begets daytime orthostatic hypotension. It is possible to treat sHTN in ways that reduce the risk of worsening OH. Furthermore, novel approaches, such as the use of local heat can control nighttime sHTN, reduce nocturia, and improve OH. Although continued progress is needed, recent findings offer hope that we can treat nocturnal sHTN and at the same time improve daytime OH, lessening the controversy whether to treat or not sHTN.

Blood pressure regulation in autonomic failure by dietary sodium, blood volume and posture

In normal subjects natriuresis is tightly coupled to dietary salt ingestion to maintain sodium balance. Likewise, blood pressure remains unchanged over a wide range of salt intake because of pressure natriuresis, whereby an increase in blood pressure stimulates renal sodium excretion to restore homeostasis. These sodium handling mechanisms are impaired in autonomic failure. When exposed to salt restriction, autonomic failure patients are unable to reduce renal sodium excretion, and their orthostatic hypotension worsens. It follows that increased dietary salt would improve orthostatic tolerance. Indeed, most clinical practice guidelines emphasize a high salt intake (6-10 g/day) in the treatment of neurogenic orthostatic hypotension. This approach has been shown to improve other conditions such as syncope and postural tachycardia syndrome, but surprisingly there is no empirical evidence to support this recommendation in orthostatic hypotension. Even though there is expert opinion consensus in its favor, it would be reassuring if at least mechanistic proof of concept studies were available. Fludrocortisone is often added to a high salt diet to improve sodium retention and increase plasma volume, but these effects are transient. Fludrocortisone is contraindicated in patients with heart failure and should be used with caution, if at all, if supine hypertension is present. In patients with supine hypertension posture is an important determinant of sodium balance; blood pressure substantially increases while supine, triggering pressure natriuresis and extensive sodium loss. Thus, avoiding the supine posture may be as important as increasing dietary salt in the management of orthostatic hypotension.

Is orthostatic hypotension and co-existing supine and seated hypertension associated with future falls in community-dwelling older adults? Results from The Irish Longitudinal Study on Ageing (TILDA)

Orthostatic hypotension (OH) often co-exists with hypertension. As increasing age affects baroreflex sensitivity, it loses its ability to reduce blood pressure when lying down. Therefore, supine hypertension may be an important indicator of baroreflex function. This study examines (i) the association between OH and future falls in community-dwelling older adults and (ii) if these associations persist in those with co-existing OH and baseline hypertension, measured supine and seated. Data from 1500 community-dwelling adults aged ≥65 years from The Irish Longitudinal Study on Ageing (TILDA) were used. Continuous beat-to-beat blood pressure was measured using digital photoplethysmography during an active stand procedure with OH defined as a drop in systolic blood pressure (SBP) ≥20 mmHg and/or ≥10 mm Hg in diastolic blood pressure (DBP) within 3 minutes of standing. OH at 40 seconds (OH40) was used as a marker of impaired early stabilisation and OH sustained over the second minute (sustained OH) was used to indicate a more persistent deficit, similar to traditional OH definitions. Seated and supine hypertension were defined as SBP ≥140 mm Hg or DBP ≥90 mm Hg. Modified Poisson models were used to estimate relative risk of falls (recurrent, injurious, unexplained) and syncope occurring over four year follow-up. OH40 was independently associated with recurrent (RR = 1.30, 95% CI = 1.02,1.65), injurious (RR = 1.43, 95% CI = 1.13,1.79) and unexplained falls (RR = 1.55, 95% CI = 1.13,2.13). Sustained OH was associated with injurious (RR = 1.55, 95% CI = 1.18,2.05) and unexplained falls (RR = 1.63, 95% CI = 1.06,2.50). OH and co-existing hypertension was associated with all falls outcomes but effect sizes were consistently larger with seated versus supine hypertension. OH, particularly when co-existing with hypertension, was independently associated with increased risk of future falls. Stronger effect sizes were observed with seated versus supine hypertension. This supports previous findings and highlights the importance of assessing orthostatic blood pressure behaviour in older adults at risk of falls and with hypertension. Observed associations may reflect underlying comorbidities, reduced cerebral perfusion or presence of white matter hyperintensities.

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.

My Treatment Approach to Multiple System Atrophy

Multiple system atrophy (MSA) is a neurodegenerative disorder primarily characterized by autonomic failure plus parkinsonism or cerebellar ataxia. The diagnosis may be challenging and is usually made at a tertiary care center. The long-term management issues are equally challenging and frequently require collaboration with the patient's local care providers. Whereas there is currently no cure for MSA, treatment focuses on the most problematic symptoms experienced by the patient. Autonomic symptoms may include severe orthostatic hypotension with syncope, urinary symptoms culminating in incontinence, constipation, anhidrosis, and erectile dysfunction. Motor symptoms include parkinsonism, cerebellar ataxia, and falls. Although certain motor symptoms may respond partially to medications, some of these medications may exacerbate autonomic problems. In this manuscript, we seek to bridge the gap between tertiary care providers and the patient's local care providers to provide multidisciplinary care to the MSA patient. Patients are often best served by management of their chronic and evolving complex problems with a team approach involving their primary care providers and subspecialists. Treatment guidelines typically list myriad therapeutic options without clarifying the most efficacious and simplest treatment strategies. Herein, we provide a guideline based on what has worked in our MSA clinic, a clinic designed to provide care throughout the disease course with subspecialty integration with the goal of empowering a partnership with the patient's home primary care providers.

Prevention and Management of Supine Hypertension in Patients With Orthostatic Hypotension

BACKGROUND

Orthostatic hypotension (OH) is a potentially debilitating condition caused by dysfunction of the autonomic nervous system, which is essential for the physiologic response to orthostatic posture. In addition to OH, autonomic dysfunction may also be associated with the development of concurrent supine hypertension (SH).

AREAS OF UNCERTAINTY

This paradoxical effect speaks to the complexity of the pathogenesis of autonomic disease and greatly complicates management of these patients. Clinicians are faced with a dilemma because aggressive treatment of orthostatic intolerance can worsen supine hypertension and attempts to control supine hypertension can worsen orthostatic intolerance.

DATA SOURCES

Systematic review of the published literature.

PREVENTION OF SUPINE HYPERTENSION

Patients should aim to avoid known stressors, perform physical maneuvers (eg, slowly getting up from bed, sleeping with head of bed elevated), manage underlying related conditions (eg, diabetes mellitus), and exercise.

MANAGEMENT OF SUPINE HYPERTENSION

With failure of conservative management, patients may advance to pharmacologic therapy. It is important to understand the underlying suspected etiology of the syndrome of supine hypertension and OH (SH-OH) to select promising pharmacologic agents. This article reviews medical treatment options to work toward achieving a better quality of life for patients afflicted with this disease. Although clonidine and beta-blockers can be used to treat hypertension without causing significant hypotension, midodrine, pyridostigmine, and droxidopa may be helpful in preventing OH.

CONCLUSION

The etiology and severity of autonomic dysfunction vary widely between patients, suggesting a need for an individualized treatment approach. Achieving perfect blood pressure control is not a realistic goal. Rather, treatment should be aimed at improving the patient's quality of life and decreasing their risk of injury and organ damage.

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.

Paroxysmal Orthostatic Ventricular Tachycardia in a Patient With Supine Hypertension and Orthostatic Hypotension

Supine orthostatic hypertension with orthostatic hypotension is an autonomic dysfunction where the patients present with hypertension when supine and with decrease in blood pressure while bearing an upright posture. We report on a 74-year-old male who was admitted with dizziness and was found to have profound orthostatic hypotension with supine hypertension. The patient also developed orthostatic paroxysmal premature ventricular beats as well as nonsustained ventricular tachycardia. In this report, we attempt to present the possible mechanism of orthostatic ventricular tachycardia in our patient and the overview of the treatment strategies used in management of patients with supine hypertension and orthostatic hypotension.

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.

Neurogenic Orthostatic Hypotension: State of the Art and Therapeutic Strategies

Neurogenic orthostatic hypotension (nOH) is a subtype of orthostatic hypotension in which patients have impaired regulation of standing blood pressure due to autonomic dysfunction. Several primary and secondary causes of this disease exist. Patients may present with an array of symptoms making diagnosis difficult. This review article addresses the epidemiology, pathophysiology, causes, clinical features, and management of nOH. We highlight various pharmacological and non-pharmacological approaches to treatment, and review the recent guidelines and our approach to nOH.

Differential diagnosis of orthostatic hypotension

Orthostatic hypotension (OH) is a common clinical manifestation characterized by a significant fall in blood pressure with postural change and is frequently accompanied by debilitating symptoms of orthostatic intolerance. The reported prevalence of OH ranges between 5 and 10% in middle-aged adults with a burden that increases concomitantly with age; in those over 60 years of age, the prevalence is estimated to be over 20%. Unfortunately, the clinical course of OH is not necessarily benign. OH patients are at an increased risk of adverse clinical outcomes including death, falls, cardiovascular and cerebrovascular events, syncope, and impaired quality of life. The differential diagnosis of OH is broad and includes acute precipitants as well as chronic underlying medical conditions, especially of neurological origin. Appropriate diagnosis relies on a systematic history and physical examination with particular attention to orthostatic vital signs, keeping in mind that ambient conditions during diagnostic testing may affect OH detection due to factors such as diurnal variation.

Neurogenic Orthostatic Hypotension: An Underrecognized Complication of Parkinson Disease

BACKGROUND

Neurogenic orthostatic hypotension (nOH) is a common source of disability but is an often untreated nonmotor symptom of Parkinson disease. The key manifestations of nOH include lightheadedness, dizziness, weakness, and fatigue when standing and engaging in activities in the upright position and result in falls, impaired activities of living, decreased quality of life, and short-term cognitive impairment. Early diagnosis and treatment of nOH are necessary to mitigate its adverse effects and reduce nOH-related symptom burden.

CASE STUDY

The management of nOH is illustrated through a case study.

MANAGEMENT CONSIDERATIONS

Alerting providers about the impact and treatment of nOH, accurate measurement of orthostatic blood pressure, and educating patients and caregivers about nonpharmacological treatment options are important strategies to manage nOH. The goal of nOH treatment is to mitigate symptoms and improve the patient's quality of life.

CONCLUSIONS

Nurses can play a crucial role in the recognition and management of nOH. Nurses who are educated about nOH are well suited to partner with care providers to treat disabling motor and nonmotor symptoms of Parkinson disease.

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.

Managing autonomic dysfunction in Parkinson's disease: a review of emerging drugs

Introduction: Autonomic dysfunction is an integral part of Parkinson disease (PD) complex and can be seen both in early and advanced stages. There is a paucity of medicines available to manage autonomic dysfunction in PD and this adds to the considerable morbidity associated with the illness.Areas covered: The pathophysiology and the available therapeutic options of autonomic dysfunction seen in PD are discussed in detail. The potential targets for novel regimens are reviewed and the available literature on the drugs emerging in management of autonomic dysfunction in PD is highlighted.Expert opinion: In the current scenario, there are several drugs that can be tried for constipation viz stool laxatives, prucalopride, prokinetic agents and a high fiber diet. Bladder dysfunction has been treated with β-agonists and with mirabegron, a selective β-3 agonist, the anticholinergic side effects are minimized, and the drug has been found to be effective. Orthostatic hypotension is managed with midodrine while droxidopa is a new drug with promising efficacy. Botulinum toxin works best for management of sialorrhea, but repeated injections are needed.

Clinical utility of midodrine and methylene blue as catecholamine-sparing agents in intensive care unit patients with shock

Shock is common in the intensive care unit, affecting up to one third of patients. Treatment of shock is centered upon managing hypotension and ensuring adequate perfusion via administration of fluids and catecholamine vasopressors. Due to the risks associated with catecholamine vasopressors, interest has grown in using catecholamine-sparing agents such as midodrine and methylene blue. Midodrine is an orally administered alpha-1 adrenergic agonist while methylene blue is an intravenously administered blue dye used to restore vascular tone and increase blood pressure. Separate MEDLINE, Scopus, and Embase database searches were conducted to assess literature revolving around these agents. Examples of search terms included "midodrine", "methylene blue", "critically ill", "shock", and "catecholamine-sparing." Several studies have evaluated their use in patients with shock and found potential benefits in terms of causing significant elevations in blood pressure and hastening catecholamine vasopressor discontinuation with few adverse effects; however, robust evidence is lacking for these off-label indications. Because of the variety of dosing strategies used and the incongruences between patient populations, it is also challenging to define finite recommendations. This review aims to summarize current evidence for the use of midodrine and methylene blue as catecholamine-sparing agents in critically ill patients with resolving or refractory shock.

Syndrome of Supine Hypertension with Orthostatic Hypotension: Pathophysiology and Clinical Approach

This article is intended to provide guidance and clinical considerations for physicians managing patients suffering from supine hypertension with orthostatic hypotension, referred to as “SH-OH”. We review the normal physiologic response to orthostasis, focusing on the appropriate changes to autonomic output in this state. Autonomic failure is discussed with a generalized overview of the disease and examination of specific syndromes that help shed light on the pathophysiology of SH-OH. The goal of this review is to provide a better framework for clinical evaluation of these patients, review treatment options, and ultimately work toward achieving a better quality of life for patients afflicted with this disease.

Reverse blood pressure dipping as marker of dysautonomia in Parkinson disease

INTRODUCTION

We sought to evaluate if the presence of abnormal circadian loss of nocturnal blood pressure dipping (reverse dipping) is associated with cardiovascular dysautonomia, a major source of morbidity in Parkinson disease.

METHODS

Consecutive Parkinson disease patients were enrolled in this cross-sectional study between January 2015 and June 2017. All subjects underwent same-day autonomic testing and 24-h ambulatory blood pressure monitoring. Cardiovascular dysautonomia was defined by the presence of at least one moderate or severe cardiovagal and adrenergic test abnormality.

RESULTS

We recruited 114 PD patients (79 males; mean age 64 ± 10 years; disease duration 6 ± 4 years). Cardiovascular dysautonomia was present in 32% (36/114). The blood pressure patterns were normal dipping in 28.9% (n = 33), extreme dipping in 6.1% (n = 7), reduced dipping in 32.5% (n = 37), and reverse dipping in 32.5% (n = 37). Reverse dipping was disproportionately prevalent in subjects with cardiovascular dysautonomia (69% vs 15%, p < 0.001). The diagnostic accuracy of reverse dipping in discriminating cardiovascular dysautonomia (AUC 0.791, specificity 84%, sensitivity 69%) was higher than that of bedside blood pressure ascertainment of neurogenic orthostatic hypotension (0.681, 66%, 69%) and supine hypertension (0.641, 78%, 50%).

CONCLUSIONS

Reverse nocturnal blood pressure dipping is a marker of cardiovascular dysautonomia in Parkinson disease, which can be screened for with ease and affordability using ambulatory blood pressure monitoring.

Diagnosis of multiple system atrophy

Multiple system atrophy (MSA) may be difficult to distinguish clinically from other disorders, particularly in the early stages of the disease. An autonomic-only presentation can be indistinguishable from pure autonomic failure. Patients presenting with parkinsonism may be misdiagnosed as having Parkinson disease. Patients presenting with the cerebellar phenotype of MSA can mimic other adult-onset ataxias due to alcohol, chemotherapeutic agents, lead, lithium, and toluene, or vitamin E deficiency, as well as paraneoplastic, autoimmune, or genetic ataxias. A careful medical history and meticulous neurological examination remain the cornerstone for the accurate diagnosis of MSA. Ancillary investigations are helpful to support the diagnosis, rule out potential mimics, and define therapeutic strategies. This review summarizes diagnostic investigations useful in the differential diagnosis of patients with suspected MSA. Currently used techniques include structural and functional brain imaging, cardiac sympathetic imaging, cardiovascular autonomic testing, olfactory testing, sleep study, urological evaluation, and dysphagia and cognitive assessments. Despite advances in the diagnostic tools for MSA in recent years and the availability of consensus criteria for clinical diagnosis, the diagnostic accuracy of MSA remains sub-optimal. As other diagnostic tools emerge, including skin biopsy, retinal biomarkers, blood and cerebrospinal fluid biomarkers, and advanced genetic testing, a more accurate and earlier recognition of MSA should be possible, even in the prodromal stages. This has important implications as misdiagnosis can result in inappropriate treatment, patient and family distress, and erroneous eligibility for clinical trials of disease-modifying drugs.

Symptomatic orthostatic hypotension in Parkinson's disease patients: Prevalence, associated factors and its impact on balance confidence

BACKGROUND

Orthostatic hypotension (OH) is a commonly reported sign of the cardiovascular autonomic dysfunctions associated with Parkinson's disease (PD). Patients might suffer from a variety of the clinical symptoms of OH, including dizziness, lightheadedness, or problems with vision and fatigue.

OBJECTIVES

To determine the prevalence of, and factors associated with, symptomatic orthostatic hypotension (OH) in Parkinson's disease (PD) and to identify any relationships between the clinical symptoms of OH and balance confidence in this patient population.

METHODS

Symptomatic OH was defined as a systolic or diastolic BP fall of ≥20 or ≥10mmHg respectively, within 3min of standing and an Orthostatic Hypotension Questionnaire (OHQ) score of more than zero. Factors related to symptomatic OH were identified from a multivariate logistic regression analysis. Pearson's correlation test was used to reveal any relationships between the clinical symptoms of OH and a patient's confidence in their ability to balance, assessed using the Activities-specific Balance Confidence (ABC) scale.

RESULTS

100 Thai PD patients were consecutively recruited into this study. The prevalence of symptomatic OH was 18%, asymptomatic OH was 4%, while 78% were patients without OH. Factors associated with symptomatic OH were age (OR, 95%CI: 1.06, 1.003-1.115, p=0.038) and hypertension (OR, 95%CI: 6.16, 1.171-32.440, p=0.032). A significant and negative correlation (r=-0.229, p=0.022) between OHQ composite scores and item 3 of the ABC scale (picking up slippers from floor), one of the movements in a vertical orientation, was found.

CONCLUSION

Elderly PD patients and with a co-morbidity of essential hypertension should be closely evaluated for the presence of symptomatic OH. In addition, they should be advised to change positions slowly, especially those in a vertical orientation.

Orthostatic hypotension: pathophysiology, assessment, treatment and the paradox of supine hypertension

Both hypertension and orthostatic hypotension (OH) are strongly age-associated and are common management problems in older people. However, unlike hypertension, management of OH has unique challenges with few well-established treatments. Not infrequently, they both coexist, further compounding the management. This review provides comprehensive information on OH, including pathophysiology, diagnostic workup and treatment, with a view to provide a practical guide to its management. Special references are made to patients with supine hypertension and postprandial hypotension and older hypertensive patients.

Role of peripheral vascular resistance as an indicator of cardiovascular abnormalities in patients with Parkinson's disease

The aim of this study was to evaluate cardiovascular autonomic modulation in response to an orthostatic stress in healthy subjects and Parkinson's disease (PD). The study included 47 controls and 56 PD patients divided into groups (vasoconstrictor PD, vasodilator PD, control) according to vasodilation/vasoconstriction response during 70° head up tilt test. Using impedance cardiography (ICG) and electrocardiography (ECG) we measured stroke volume, cardiac output, left ventricular work index, left ventricular ejection time, acceleration index, index of contractility, Heather index, thoracic fluid content, total peripheral resistance, total arterial compliance. We also analyzed heart rate variability (HRV), using spectral analysis and continuous blood pressure (contBP). At rest, the vasodilator PD group showed significantly higher values of total peripheral resistance and lower values of stroke volume and cardiac output, compared to the vasoconstrictor PD and the control groups. A post-tilt drop in ∆ (change rest - tilt) systolic blood pressure, ∆mean blood pressure, ∆total peripheral resistance and ∆Heather index, and a significantly lower increase in ∆diastolic blood pressure was observed in subjects from the vasodilator PD group compared to the vasoconstrictor PD and the control groups. No statistically significant differences were observed for HRV parameters between the vasoconstrictor and vasodilator PD groups, P > .05. Longer duration and higher disease stage of PD correlated with a reduction in post-tilt systolic blood pressure changes in vasodilator group. Positive inotropy of the cardiac muscle represents a significant factor preventing orthostatic hypotension in PD subjects with a concurrent drop in peripheral vascular resistance during orthostatic stress.

Leg fluid accumulation during prolonged sitting

The accumulation of fluid in the legs due to sedentariness can be a health risk in extreme cases. Negative health impacts associated with leg fluid accumulation include leg edema and risk of blood clots. Furthermore, fluid accumulating in the legs is accompanied by fluid shift into the upper body which is also associated with health risks such as: increased blood pressure when lying down, respiratory problems in people with heart failure, and increased sleep apnea. Understanding the pattern by which fluid accumulates in the legs can aid in the development of devices for reducing leg fluid accumulation. The purpose of this study was to characterize the time course of fluid accumulation over a two-and-half-hour seated period. Non-obese participants with sleep apnea and no other co-morbidities were included in the sample as part of a larger study. Leg fluid was measured continuously using a method of bioelectrical impedance. Participants were first asked to lie supine for 30 minutes as a washout, and then sat with their legs still for two and a half hours. The main finding of this study is that the pattern of leg fluid accumulation differed in the first 45 minutes compared to the latter 105 minutes. In the first 45 minutes, fluid accumulated according to first order exponential function. In the latter period, fluid accumulated according to a linear function. The initial exponential accumulation is likely due to the large increase in capillary pressure caused by rapid blood flow into the legs due to gravity, leading to substantial filtration of blood plasma into the tissue spaces. The latter linear portion likely represents continued slow filtration of fluid out of the vasculature and into the tissue spaces. This is the first study to show that fluid accumulation in the legs is a combination of an exponential and linear functions. The linear increase identifies that there is no foreseeable point in which leg fluid stops accumulating while sitting for prolonged periods.

Neurogenic orthostatic hypotension and supine hypertension in Parkinson's disease and related synucleinopathies: prioritisation of treatment targets

Neurogenic orthostatic hypotension and supine hypertension are common manifestations of cardiovascular dysautonomia in Parkinson's disease and related synucleinopathies. Because these disorders are haemodynamic opposites, improvement in one might be achieved at the expense of worsening of the other. Thus, management decisions necessitate assessment of the individual risks for patients with coexistent neurogenic orthostatic hypotension and supine hypertension. Whereas neurogenic orthostatic hypotension poses risks for falls and can be associated with cognitive impairment in the short term, chronic supine hypertension can be associated with stroke and myocardial infarction in the long term. Because few clinical trial data exist for outcomes in patients with coexistent neurogenic orthostatic hypotension and supine hypertension, clinicians need to balance, on the basis of comorbidities and disease staging, the potential immediate benefits of treatment for neurogenic orthostatic hypotension and the long-term risks of supine hypertension treatment in each patient. Future research needs to focus on ascertaining a safe degree of supine hypertension when treating neurogenic orthostatic hypotension; the effectiveness of nocturnal antihypertensive therapy in patients with coexistent neurogenic orthostatic hypotension and supine hypertension; and the prevalence, scope, and therapeutic requirements for managing neurogenic orthostatic hypotension that manifests with falls or cognitive impairment, but without postural lightheadedness or near syncope.

The recommendations of a consensus panel for the screening, diagnosis, and treatment of neurogenic orthostatic hypotension and associated supine hypertension

Neurogenic orthostatic hypotension (nOH) is common in patients with neurodegenerative disorders such as Parkinson’s disease, multiple system atrophy, pure autonomic failure, dementia with Lewy bodies, and peripheral neuropathies including amyloid or diabetic neuropathy. Due to the frequency of nOH in the aging population, clinicians need to be well informed about its diagnosis and management. To date, studies of nOH have used different outcome measures and various methods of diagnosis, thereby preventing the generation of evidence-based guidelines to direct clinicians towards ‘best practices’ when treating patients with nOH and associated supine hypertension. To address these issues, the American Autonomic Society and the National Parkinson Foundation initiated a project to develop a statement of recommendations beginning with a consensus panel meeting in Boston on November 7, 2015, with continued communications and contributions to the recommendations through October of 2016. This paper summarizes the panel members’ discussions held during the initial meeting along with continued deliberations among the panel members and provides essential recommendations based upon best available evidence as well as expert opinion for the (1) screening, (2) diagnosis, (3) treatment of nOH, and (4) diagnosis and treatment of associated supine hypertension.

Orthostatic hypotension in Parkinson's disease: Does it matter if asymptomatic?

INTRODUCTION

Orthostatic hypotension (OH) may frequently be asymptomatic in patients with Parkinson's disease (PD). However, the relationship between symptomatic/asymptomatic status and functional disability remains unclear.

METHODS

Using orthostatic blood pressure (BP) measurements and the Orthostatic Hypotension Symptom Assessment (OHSA) questionnaire, 121 consecutive PD patients without history of chronic hypertension and not taking alpha-adrenergic antagonists for bladder disorders were classified according to (1) OH symptomatic status, based on presence/absence of orthostatic symptoms (symptomatic OH: OHSA item 1 ≥ 1), and (2) OH severity, based on the magnitude of BP fall on the lying-to-standing test: OH- (<20/10 mmHg); moderate OH+ (≥20/10 mmHg but < 30/15 mmHg); and severe OH+ (≥30/15 mmHg). The primary endpoints were the activities of daily living/instrumental activities of daily living (ADL/iADL) and the Ambulatory Capacity Measure (ACM). Secondary endpoints included PD quality of life (PDQ-8) and prevalence of falls.

RESULTS

The overall prevalence of OH+ was 30.6% (37/121 patients), with 62.2% symptomatic (23/37) and 37.8% asymptomatic (14/37). Symptomatic and asymptomatic OH + patients had similar impairments in ADL/iADL and ACM, significantly worse than OH- (p ≤ 0.035). There was a trend for worse ADL/iADL and ACM scores in severe OH + compared to moderate OH+, but both were worse than OH- (p ≤ 0.048). Symptomatic and asymptomatic OH + showed similar impairment in PDQ-8 and higher prevalence of falls compared to OH-.

CONCLUSIONS

Asymptomatic OH+ was associated with similar impairments in ADL/iADL and ACM than symptomatic OH+. These findings support screening for OH in PD patients regardless of postural lightheadedness.

Residual sympathetic tone is associated with reduced insulin sensitivity in patients with autonomic failure

PURPOSE

Parkinson disease, an α-synucleinopathy, is associated with reduced insulin sensitivity, impaired glucose tolerance, and diabetes mellitus. Importantly, these metabolic alterations have been shown to contribute to disease progression. The purpose of this study was to determine if reduced insulin sensitivity is also present in other α-synucleinopathies associated with autonomic failure.

METHODS

We studied 19 patients with multiple system atrophy and 26 patients with pure autonomic failure. For comparison, we studied 8 healthy controls matched for body mass index. Insulin sensitivity and beta cell function were calculated using fasting glucose and insulin levels according to the homeostatic model assessment 2. A multiple linear regression model was performed to determine factors that predict insulin sensitivity in autonomic failure.

RESULTS

There was a significant difference in insulin sensitivity among groups (P = 0.048). This difference was due to lower insulin sensitivity in multiple system atrophy patients: 64% [interquartile range (IQR), 43 to 117] compared to healthy controls 139% (IQR, 83 to 212), P = 0.032. The main factor that contributed to the reduced insulin sensitivity was the presence of supine hypertension and residual sympathetic tone.

CONCLUSIONS

Multiple system atrophy patients have reduced insulin sensitivity that is associated with residual sympathetic activation and supine hypertension. These patients may therefore be at high risk for development of impaired glucose tolerance and diabetes mellitus.

Dysautonomia in Parkinson disease

Dysautonomias are conditions in which altered function of one or more components of the autonomic nervous system (ANS) adversely affects health. This review updates knowledge about dysautonomia in Parkinson disease (PD). Most PD patients have symptoms or signs of dysautonomia; occasionally, the abnormalities dominate the clinical picture. Components of the ANS include the sympathetic noradrenergic system (SNS), the parasympathetic nervous system (PNS), the sympathetic cholinergic system (SCS), the sympathetic adrenomedullary system (SAS), and the enteric nervous system (ENS). Dysfunction of each component system produces characteristic manifestations. In PD, it is cardiovascular dysautonomia that is best understood scientifically, mainly because of the variety of clinical laboratory tools available to assess functions of catecholamine systems. Most of this review focuses on this aspect of autonomic involvement in PD. PD features cardiac sympathetic denervation, which can precede the movement disorder. Loss of cardiac SNS innervation occurs independently of the loss of striatal dopaminergic innervation underlying the motor signs of PD and is associated with other nonmotor manifestations, including anosmia, REM behavior disorder, orthostatic hypotension (OH), and dementia. Autonomic dysfunction in PD is important not only in clinical management and in providing potential biomarkers but also for understanding disease mechanisms (e.g., autotoxicity exerted by catecholamine metabolites). Since Lewy bodies and Lewy neurites containing alpha-synuclein constitute neuropathologic hallmarks of the disease, and catecholamine depletion in the striatum and heart are characteristic neurochemical features, a key goal of future research is to understand better the link between alpha-synucleinopathy and loss of catecholamine neurons in PD.

Management of neurogenic orthostatic hypotension in patients with autonomic failure

The maintenance of blood pressure in the upright position requires intact autonomic cardiovascular reflexes. Diseases that affect the sympathetic innervation of the cardiovascular system result in a sustained fall in blood pressure upon standing (i.e., neurogenic orthostatic hypotension) that can impair the blood supply to the brain and other organs and cause considerable morbidity and mortality. Here we review treatment options for neurogenic orthostatic hypotension and include an algorithm for its management that emphasizes the importance of non-pharmacologic measures and provides guidance on pharmacologic treatment options.

Incidence of cerebrovascular lesions in pure autonomic failure

In pure autonomic failure (PAF) - a rare form of primary dysautonomia - some patients show cerebrovascular lesions usually found in hypertensive subjects. In an autonomic laboratory records of patients with a definitive diagnosis of PAF having had cerebral imaging (cMRI, cCT) were analysed retrospectively. Tilt table data (supine/tilted), 24 hour blood pressure recordings (day/night) and serum catecholamine levels were correlated with cerebrovascular lesions and also compared to published normal values. 50 PAF patients (23 female, 27 male) were identified, mean age 67 years (sd 9.5). Out of these 35 (70%) had pathologic cerebral scans showing white matter lesions (WML) in 30, lacunar strokes in 5 and hemispheric stroke and microbleeds each in 1. Age and supine systolic blood pressure were significantly elevated in patients with pathologic scans (70 compared to 61 years [p=0.007], and 170 compared to 154 mmHg [p=0.045]). Out of 28 patients with WML and ambulatory blood pressure recordings available 24 were non-dippers. The data show that the frequency of WML is lower in PAF patients aged 60 to 80 years compared to age matched community based samples. Although PAF usually results in hypotension, a frequent complication is supine hypertension. Although the overall frequency of WML seems to be reduced in PAF, a number of patients with elevated supine systolic blood pressure (>160 mmHg) develop WML and some of these suffer stroke.

Twenty-four hour non-invasive ambulatory blood pressure and heart rate monitoring in Parkinson's disease

Non-motor symptoms are now commonly recognized in Parkinson's disease (PD) and can include dysautonomia. Impairment of cardiovascular autonomic function can occur at any stage of PD but is typically prevalent in advanced stages or related to (anti-Parkinsonian) drugs and can result in atypical blood pressure (BP) readings and related symptoms such as orthostatic hypotension (OH) and supine hypertension. OH is usually diagnosed with a head-up-tilt test (HUT) or an (active) standing test (also known as Schellong test) in the laboratory, but 24 h ambulatory blood pressure monitoring (ABPM) in a home setting may have several advantages, such as providing an overview of symptoms in daily life alongside pathophysiology as well as assessment of treatment interventions. This, however, is only possible if ABPM is administrated correctly and an autonomic protocol (including a diary) is followed which will be discussed in this review. A 24-h ABPM does not only allow the detection of OH, if it is present, but also the assessment of cardiovascular autonomic dysfunction during and after various daily stimuli, such as postprandial and alcohol dependent hypotension, as well as exercise and drug induced hypotension. Furthermore, information about the circadian rhythm of BP and heart rate (HR) can be obtained and establish whether or not a patient has a fall of BP at night (i.e., "dipper" vs. non-"dipper"). The information about nocturnal BP may also allow the investigation or detection of disorders such as sleep dysfunction, nocturnal movement disorders, and obstructive sleep apnea, which are common in PD. Additionally, a 24-h ABPM should be conducted to examine the effectiveness of OH therapy. This review will outline the methodology of 24 h ABPM in PD, summarize findings of such studies in PD, and briefly consider common daily stimuli that might affect 24 h ABPM.

Arterial hypertension, a tricky side of Parkinson's disease: physiopathology and therapeutic features

The role of arterial hypertension (HT) as risk factor for Parkinson's disease (PD) is still debated. Case-control and retrospective studies do not support an association between HT and PD and the risk of PD seems to be lower in hypertensive than in normotensive subjects. In addition, the use of calcium-channel blockers (CCBs) and angiotensin-converting enzyme inhibitors seems to have a protective effect on the risk of developing PD. In clinical practice, a crucial finding in subjects with PD is the high supine systolic blood pressure (SBP) coupled with orthostatic hypotension (OH). It is not clear whether this SBP load could be a risk factor for target organ damage as this load can be largely due to the drugs used to treat OH (i.e., fludrocortisone acetate, midodrine) or PD itself (i.e., monoamine oxidase inhibitors, dopamine D2-receptor antagonists). This blood pressure (BP) load is largely independent of medications as the 40 % of subjects with PD have a non-dipping pattern of BP during 24 h ambulatory monitoring (24-h ABPM). In PD, nocturnal HT is usually asymptomatic and 24-h ABPM should be used to track both supine HT and OH. Treatment of HT in PD is difficult because the reduction of supine BP could worsen OH. To avoid this, short-acting dihydropyridine CCBs, clonidine or nitrates are recommended, assuming between meals, in late afternoon or in the evening in avoiding an aggravation in the post-prandial hypotension characteristic of PD.

Cognitive and MRI correlates of orthostatic hypotension in Parkinson's disease

Orthostatic hypotension (OH) is a frequent nonmotor feature of Parkinson's disease (PD), and its occurrence has been associated with cognitive impairment. The underlying mechanism could be mediated by development of cerebrovascular disease induced by chronic or episodic hypoperfusion, but the extent of brain vascular load in PD patients with OH has never been investigated. This study aimed to assess the relationship between OH and cognitive function in PD patients and to investigate the contribution of brain vascular lesions. Forty-eight PD patients underwent a tilt table test (TT) to assess supine and orthostatic blood pressure as well as an extensive neuropsychological evaluation to evaluate cognitive function. Brain magnetic resonance imaging was acquired in 44/48 patients and analyzed by a visual semiquantitative scale. Twenty-three patients presented OH at TT (13/23 were symptomatic), and 25 did not. There were no differences in motor severity or disease duration between patients with and without OH. In patients with OH we found significantly worse cognitive performance in specific tasks, such as sustained attention, visuospatial and verbal memory, compared with patients without OH. However, there were no differences in vascular burden between the two groups. Our study confirms that there is an association between OH and selective cognitive deficits in PD, but rebuts the hypothesis that this is underlined by the development of cerebrovascular disease.

Dysautonomia: perioperative implications

Severe autonomic failure occurs in approximately 1 in 1,000 people. Such patients are remarkable for the striking and sometimes paradoxic responses they manifest to a variety of physiologic and pharmacologic stimuli. Orthostatic hypotension is often the finding most commonly noted by physicians, but a myriad of additional and less understood findings also occur. These findings include supine hypertension, altered drug sensitivity, hyperresponsiveness of blood pressure to hypo/hyperventilation, sleep apnea, and other neurologic disturbances. In this article the authors will review the clinical pathophysiology that underlies autonomic failure, with a particular emphasis on those aspects most relevant to the care of such patients in the perioperative setting. Strategies used by clinicians in diagnosis and treatment of these patients, and the effect of these interventions on the preoperative, intraoperative, and postoperative care that these patients undergo is a crucial element in the optimized management of care in these patients.

Orthostatic hypotension: a common, serious and underrecognized problem in hospitalized patients

Orthostatic hypotension (OH) is strongly age-dependent, with a prevalence ranging from 5% to 11% in middle age to 30% or higher in the elderly. It is also closely associated with other common chronic diseases, including hypertension, congestive heart failure, diabetes mellitus, and Parkinson's disease. Most studies of OH have been performed in population cohorts or elderly residents of extended care facilities, but in this review, we draw attention to a problem little studied to date: OH in hospitalized patients. The prevalence of OH in all hospitalized patients is not known because most studies have included only older individuals with multiple comorbid diseases, but in some settings as many as 60% of hospitalized adults have postural hypotension. Hospitalized patients are particularly vulnerable to the consequences of OH, particularly falls, because postural blood pressure (BP) regulation may be disturbed by many common acute illnesses as well as by bed rest and drug treatment. The temporal course of OH in hospitalized patients is uncertain, both because the reproducibility of OH is poor and because conditions affecting postural BP regulation may vary during hospitalization. Finally, OH during hospitalization often persists after discharge, where, in addition to creating an ongoing risk of falls and syncope, it is strongly associated with risk of incident cardiovascular complications, including myocardial infarction, heart failure, stroke, and all-cause mortality. Because OH is a common, easily diagnosable, remediable condition with important clinical implications, we encourage caregivers to monitor postural BP change in patients throughout hospitalization.

Morphological substrate of autonomic failure and neurohormonal dysfunction in multiple system atrophy: impact on determining phenotype spectrum

Autonomic failure is a prominent clinical feature of patients with multiple system atrophy (MSA). Neurohormonal dysfunction is also a frequent accompaniment in patients with MSA. The determination of the pathological involvement of the autonomic neurons, which are responsible for circadian rhythms and responses to stress, provides new insight into autonomic failure and neurohormonal dysfunction in MSA. The disruptions of circadian rhythms and responses to stress may underlie the impairment of homeostatic integration responsible for cardiovascular and respiratory failures. These notions lead to the hypothesis that a pathological involvement of autonomic neurons is a significant factor of the poor prognosis of MSA. Beyond this perspective, endeavors to find the morphological phenotype that represents a predominant loss of autonomic neurons may elucidate the full spectrum of pathological involvements in MSA.

The effect of rosiglitazone on orthostatic tolerance during heat exposure in individuals with type II diabetes

BACKGROUND AND METHODS

Twenty-two subjects with type II diabetes and 30 control subjects participated in a 1-year study to examine the effect of rosiglitazone on heart rate variability at rest and the blood pressure, heart rate, and blood flow changes during a change in body position from horizontal to the 45 degrees head up position. To assess nerve damage, latency was measured for sensory nerves in the foot.

RESULTS

The results of the experiments showed that subjects with diabetes had an approximate 50% impairment in sural, medial, and lateral plantar nerve latency. After 1 year of administration of rosiglitazone, there was improvement by about 50% in sural, medial, and lateral nerve plantar latency. The changes in blood flow in the subject with diabetes was less than half that of control subjects, during tilting from the horizontal to the vertical position. Heart rate variability was less during tilt, and the blood pressure change was significantly greater in subjects with diabetes than control subjects (P < 0.01). After administration of rosiglitazone for 1 year, the changes in blood flow, blood pressure, and heart rate, while improving by about half, were not equal to those of age matched controls (P < 0.01).

CONCLUSIONS

The results of the experiments indicate that the insulin sensitizer rosiglitazone cannot reverse all of the damage associated with diabetes to the autonomic nervous system, but much can be reversed.

The patient with supine hypertension and orthostatic hypotension: a clinical dilemma

Coexistent supine hypertension and orthostatic hypotension (SH-OH) pose a particular therapeutic dilemma, as treatment of one aspect of the condition may worsen the other. Studies of SH-OH are to be found by and large on patients with autonomic nervous disorders as well as patients with chronic arterial hypertension. In medical practice, however, the aetiologies and clinical presentation of the syndrome seem to be more varied. In the most typical cases the diagnosis is straightforward and the responsible mechanism evident. In those patients with mild or non-specific symptoms, the diagnosis is more demanding and the investigation may benefit from results of the tilt test, bedside autonomic tests as well as haemodynamic assessment. Discrete patterns of SH-OH may be recognisable. This review focuses on the management of the patient with coexistent SH-OH.