Abstract P393: Orthostatic Heart Rate-Blood Pressure Relationship Identifies Neurogenic Orthostatic Hypotension

Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Alejandro Velasco ◽  
Luis E Okamoto ◽  
Emily M Garland ◽  
Chang Yu ◽  
Italo Biaggioni

Background: Neurogenic orthostatic hypotension (nOH) is a chronic disabling condition associated with significant morbidity and mortality. Currently, the diagnosis of nOH relies on impaired autonomic reflexes as determined by testing available only in specialized centers. Our objective was to test the hypothesis that a blunted heart rate (HR) increase in response to a given systolic blood pressure (SBP) fall will correctly diagnose nOH. Methods: We performed a retrospective study of nOH patients (studied in an inpatient environment off medications that can interfere with autonomic function) and control subjects. nOH was diagnosed on the basis of SBP fall ≥20 mmHg on standing associated with a decrease in SBP≥ 20 mmHg during phase 2 of the Valsalva maneuver and absence of phase 4 SBP overshoot. Controls had any SBP fall on standing but intact autonomic reflexes. Receiver operator characteristic curve (ROC) analysis was performed on the ratio of the changes from supine to 3 min standing in HR and SBP (ΔHR/ΔSBP). Results: We studied 171 nOH patients (66±1 years, males 61%, multiple system atrophy 42%, Parkinson disease 14%, pure autonomic failure 32% and undetermined 12%) and 53 controls (51±3 years, males 28%). nOH patients had a greater drop in standing SBP (-63±2 vs. -16±4 mmHg in controls; p<0.01) but a smaller increase in HR (13±1 vs. 18±1 bpm in controls; p<0.01). The ROC analysis at 95% Confidence Interval showed that a ΔHR/ΔSBP ratio <0.445 had a 81% specificity and 79% sensitivity in identifying nOH (AUC=0.86, p<0.01. Figure). Conclusions: Our study suggests that a simple ratio of ΔSBP/ΔHR <0.445 during a posture test in clinic can reliably identify patients with nOH.

2011 ◽  
Vol 165 (2) ◽  
pp. 211-212
Author(s):  
Yuko Kuwahara ◽  
Mika Imai ◽  
Yutaka Yoshida ◽  
Yuuki Shimizu ◽  
Naoki Nishimura ◽  
...  

2010 ◽  
Vol 108 (6) ◽  
pp. 1591-1594 ◽  
Author(s):  
Scott L. Davis ◽  
Craig G. Crandall

The Valsalva maneuver can be used as a noninvasive index of autonomic control of blood pressure and heart rate. The purpose of this investigation was to test the hypothesis that sympathetic mediated vasoconstriction, as referenced by hemodynamic responses during late phase II (phase IIb) of the Valsalva maneuver, is inhibited during whole body heating. Seven individuals (5 men, 2 women) performed three Valsalva maneuvers (each at a 30-mmHg expiratory pressure for 15 s) during normothermia and again during whole body heating (increase sublingual temperature ∼0.8°C via water-perfused suit). Each Valsalva maneuver was separated by a minimum of 5 min. Beat-to-beat mean arterial blood pressure (MAP) and heart rate were measured during each Valsalva maneuver, and responses for each phase were averaged across the three Valsalva maneuvers for both thermal conditions. Baseline MAP was not significantly different between normothermic (88 ± 11 mmHg) and heat stress (84 ± 9 mmHg) conditions. The change in MAP (ΔMAP) relative to pre-Valsalva MAP during phases IIa and IIb was significantly lower during heat stress (IIa = −20 ± 8 mmHg; IIb = −13 ± 7 mmHg) compared with normothermia (IIa = −1 ± 15 mmHg; IIb = 3 ± 13 mmHg). ΔMAP from pre-Valsalva baseline during phase IV was significantly higher during heat stress (25 ± 10 mmHg) compared with normothermia (8 ± 9 mmHg). Counter to the proposed hypothesis, the increase in MAP from the end of phase IIa to the end of phase IIb during heat stress was not attenuated. Conversely, this increase in MAP tended to be greater during heat stress relative to normothermia ( P = 0.06), suggesting that sympathetic activation may be elevated during this phase of the Valsalva while heat stressed. These data show that heat stress does not attenuate this index of vasoconstrictor responsiveness during the Valsalva maneuver.


2018 ◽  
Vol 52 (12) ◽  
pp. 1182-1194 ◽  
Author(s):  
Jack J. Chen ◽  
Yi Han ◽  
Jonathan Tang ◽  
Ivan Portillo ◽  
Robert A. Hauser ◽  
...  

Background: The comparative effects of droxidopa and midodrine on standing systolic blood pressure (sSBP) and risk of supine hypertension in patients with neurogenic orthostatic hypotension (NOH) are unknown. Objective: To perform a Bayesian mixed-treatment comparison meta-analysis of droxidopa and midodrine in the treatment of NOH. Methods: The PubMed, CENTRAL, and EMBASE databases were searched up to November 16, 2016. Study selection consisted of randomized trials comparing droxidopa or midodrine with placebo and reporting on changes in sSBP and supine hypertension events. Data were pooled to perform a comparison among interventions in a Bayesian fixed-effects model using vague priors and Markov chain Monte Carlo simulation with Gibbs sampling, calculating pooled mean changes in sSBP and risk ratios (RRs) for supine hypertension with associated 95% credible intervals (CrIs). Results: Six studies (4 administering droxidopa and 2 administering midodrine) enrolling a total of 783 patients were included for analysis. The mean change from baseline in sSBP was significantly greater for both drugs when compared with placebo (droxidopa 6.2 mm Hg [95% CrI = 2.4-10] and midodrine 17 mm Hg [95% CrI = 11.4-23]). Comparative analysis revealed a significant credible difference between droxidopa and midodrine. The RR for supine hypertension was significantly greater for midodrine, but not droxidopa, when compared with placebo (droxidopa RR = 1.4 [95% CrI = 0.7-2.7] and midodrine RR = 5.1 [95% CrI = 1.6-24]). Conclusion and Relevance: In patients with NOH, both droxidopa and midodrine significantly increase sSBP, the latter to a greater extent. However, midodrine, but not droxidopa, significantly increases risk of supine hypertension.


2020 ◽  
Vol 129 (3) ◽  
pp. 459-466
Author(s):  
Julian M. Stewart ◽  
Archana Kota ◽  
Mary Breige O’Donnell-Smith ◽  
Paul Visintainer ◽  
Courtney Terilli ◽  
...  

Significant initial orthostatic hypotension (IOH) occurs in ~50% of postural tachycardia syndrome (POTS) patients and 13% of controls. Heart rate and blood pressure recovery are prolonged in IOH sustaining lightheadedness; IOH is more prevalent and severe in POTS. Altered cerebral blood flow and cardiorespiratory regulation are more prevalent in POTS. Altered heart rate variability and baroreflex gain may cause nearly instantaneous lightheadedness in POTS. IOH alone fails to confer a strong probability of POTS.


2019 ◽  
Vol 127 (5) ◽  
pp. 1386-1402 ◽  
Author(s):  
E. Benjamin Randall ◽  
Anna Billeschou ◽  
Louise S. Brinth ◽  
Jesper Mehlsen ◽  
Mette S. Olufsen

The Valsalva maneuver (VM) is a diagnostic protocol examining sympathetic and parasympathetic activity in patients with autonomic dysfunction (AD) impacting cardiovascular control. Because direct measurement of these signals is costly and invasive, AD is typically assessed indirectly by analyzing heart rate and blood pressure response patterns. This study introduces a mathematical model that can predict sympathetic and parasympathetic dynamics. Our model-based analysis includes two control mechanisms: respiratory sinus arrhythmia (RSA) and the baroreceptor reflex (baroreflex). The RSA submodel integrates an electrocardiogram-derived respiratory signal with intrathoracic pressure, and the baroreflex submodel differentiates aortic and carotid baroreceptor regions. Patient-specific afferent and efferent signals are determined for 34 control subjects and 5 AD patients, estimating parameters fitting the model output to heart rate data. Results show that inclusion of RSA and distinguishing aortic/carotid regions are necessary to model the heart rate response to the VM. Comparing control subjects to patients shows that RSA and baroreflex responses are significantly diminished. This study compares estimated parameter values from the model-based predictions to indices used in clinical practice. Three indices are computed to determine adrenergic function from the slope of the systolic blood pressure in phase II [ α (a new index)], the baroreceptor sensitivity ( β), and the Valsalva ratio ( γ). Results show that these indices can distinguish between normal and abnormal states, but model-based analysis is needed to differentiate pathological signals. In summary, the model simulates various VM responses and, by combining indices and model predictions, we study the pathologies for 5 AD patients. NEW & NOTEWORTHY We introduce a patient-specific model analyzing heart rate and blood pressure during a Valsalva maneuver (VM). The model predicts autonomic function incorporating the baroreflex and respiratory sinus arrhythmia (RSA) control mechanisms. We introduce a novel index ( α) characterizing sympathetic activity, which can distinguish control and abnormal patients. However, we assert that modeling and parameter estimation are necessary to explain pathologies. Finally, we show that aortic baroreceptors contribute significantly to the VM and RSA affects early VM.


2020 ◽  
Vol 14 ◽  
pp. 117954682095341
Author(s):  
Dinesh K Kalra ◽  
Anvi Raina ◽  
Sumit Sohal

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.


Author(s):  
Juan Francisco Idiaquez ◽  
Juan Idiaquez ◽  
Juan Carlos Casar ◽  
Italo Biaggioni

Abstract Maintenance of upright blood pressure critically depends on the autonomic nervous system and its failure leads to neurogenic orthostatic hypotension (NOH). The most severe cases are seen in neurodegenerative disorders caused by abnormal α-synuclein deposits: multiple system atrophy (MSA), Parkinson’s disease, Lewy body dementia, and pure autonomic failure (PAF). The development of novel treatments for NOH derives from research in these disorders. We provide a brief review of their underlying pathophysiology relevant to understand the rationale behind treatment options for NOH. The goal of treatment is not to normalize blood pressure but rather to improve quality of life and prevent syncope and falls by reducing symptoms of cerebral hypoperfusion. Patients not able to recognize NOH symptoms are at a higher risk for falls. The first step in the management of NOH is to educate patients on how to avoid high-risk situations and providers to identify medications that trigger or worsen NOH. Conservative countermeasures, including diet and compression garments, should always precede pharmacologic therapies. Volume expanders (fludrocortisone and desmopressin) should be used with caution. Drugs that enhance residual sympathetic tone (pyridostigmine and atomoxetine) are more effective in patients with mild disease and in MSA patients with spared postganglionic fibers. Norepinephrine replacement therapy (midodrine and droxidopa) is more effective in patients with neurodegeneration of peripheral noradrenergic fibers like PAF. NOH is often associated with other cardiovascular diseases, most notably supine hypertension, and treatment should be adapted to their presence.


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