Hemodynamic Mechanisms Underlying Initial Orthostatic Hypotension, Delayed Recovery and Orthostatic Hypotension

Effect of orthostatic hypotension on long-term prognosis of elderly patients with stable coronary artery disease: a retrospective cohort study

Background

The long-term prognosis of patients with stable coronary artery disease (CAD) combined with orthostatic hypotension (OH) has rarely been reported. This research was designed to examine whether OH increases the risk of all-cause mortality and cardiovascular death among patients with stable CAD.

Methods

We retrospectively analyzed retired military personnel over 65 years of age who were hospitalized at the General Hospital of Southern Theater Command of the Chinese People's Liberation Army between March and July 2010. A total of 924 patients with stable CAD were included, among whom 263 had OH. The risk of all-cause mortality and cardiovascular death in OH and non-OH groups were analyzed with the Cox proportional hazards models, and restricted cubic spline plots were utilized for subgroup analyses. Furthermore, competing risk models were applied for sensitivity analyses.

Results

The median age of the patients was 82.00 (80.00-85.00) years. Over 159 months of follow-up, the loss to follow-up rate was 2.27%, and all-cause mortality was observed in 574 (63.57%) patients, including 184 with OH. Moreover, cardiovascular death occurred in 127 patients (13.73%), with 58 cases associated with OH. Although the relationship between OH and all-cause mortality was non-significant [body mass index (BMI) < 25 group, adjusted hazard ratio (HR) = 1.10 with a 95% confidence interval (CI): 0.82-1.40; BMI ≥ 25 group, adjusted HR = 1.30, 95% CI: 0.98-1.70], it was independently related to a growing risk of cardiovascular death (adjusted HR = 1.80, 95% CI: 1.20-2.60). This finding was further validated by using a competing risk model (subdistribution HR = 1.74, 95% CI: 1.22-2.49). Moreover, age, low-density lipoprotein cholesterol, and frequency of hospital admissions were identified as risk factors of cardiovascular death among patients with OH (P < 0.05).

Conclusion

Our study, based on retired military personnel with stable CAD, found that OH led to a significantly higher risk of cardiovascular death, but it was not noticeably associated with all-cause mortality on long-term prognosis.

Haemodynamic Parameters Underlying the Relationship between Sarcopenia and Blood Pressure Recovery on Standing

BACKGROUND

Sarcopenia, delayed blood pressure (BP) recovery following standing, and orthostatic hypotension (OH) pose significant clinical challenges associated with ageing. While prior studies have established a link between sarcopenia and impaired BP recovery and OH, the underlying haemodynamic mechanisms remain unclear.

METHODS

We enrolled 107 participants aged 50 and above from a falls and syncope clinic, conducting an active stand test with continuous non-invasive haemodynamic measurements. Hand grip strength and five-chair stand time were evaluated, and muscle mass was estimated using bioelectrical impedance analysis. Participants were categorised as non-sarcopenic or sarcopenic. Employing mixed-effects linear regression, we modelled the effect of sarcopenia on mean arterial pressure and heart rate after standing, as well as Modelflow®-derived parameters such as cardiac output, total peripheral resistance, and stroke volume, while adjusting for potential confounders.

RESULTS

Sarcopenia was associated with diminished recovery of mean arterial pressure during the 10-20 s period post-standing (β -0.67, p < 0.001). It also resulted in a reduced ascent to peak (0-10 s) and recovery from peak (10-20 s) of cardiac output (β -0.05, p < 0.001; β 0.06, p < 0.001). Furthermore, sarcopenia was associated with attenuated recovery (10-20 s) of total peripheral resistance from nadir (β -0.02, p < 0.001) and diminished recovery from peak (10-20 s) of stroke volume (β 0.54, p < 0.001). Notably, heart rate did not exhibit a significant association with sarcopenia status at any time interval post-standing.

CONCLUSION

The compromised BP recovery observed in sarcopenia appears to be driven by an initial reduction in the peak of cardiac output, followed by attenuated recovery of cardiac output from its peak and total peripheral resistance from its nadir. This cardiac output finding seems to be influenced by stroke volume rather than heart rate. Possible mechanisms for these findings include cardio-sarcopenia, the impact of sarcopenia on the autonomic nervous system, and/or the skeletal muscle pump.

The differences of orthostatic hypotension in patients with Parkinson's disease and multiple system atrophy

Background

Multiple system atrophy (MSA) and Parkinson's disease (PD) have similar clinical presentations in their early stages. Orthostatic hypotension (OH) is a common autonomic dysfunction associated with MSA and PD. Heart rate (HR) and systolic blood pressure (SBP) changes are measured in response to the active standing test, which is widely used to screen for cardiovascular autonomic function.

Objectives and methods

Overall, 255 patients (67 MSA, 188 PD) underwent continuous beat-to-beat non-invasive BP monitoring and active standing test. The total standing time was 10 min, and the BP differences between both groups were compared to determine whether the ΔHR/ΔSBP can differentiate both conditions.

Results

Classical orthostatic hypotension (COH) (52%) and initial OH (19%) were most common in MSA and PD, respectively. MSA had a higher HR (75.0 ± 9.7 vs. 71.0 ± 10.7, P = 0.008) than PD in the supine position. SBP (135.70 ± 15.68 mmHg vs. 127.31 ± 15.14 mmHg, P = 0.106), diastolic BP (78.45 ± 12.36 mmHg vs. 67.15 ± 13.39 mmHg, P = 0.009) and HR (73.94 ± 8.39 bpm vs. 71.08 ± 13.52 bpm, P = 0.389) at baseline were higher in MSA-COH than in PD-COH. After adjusting for age and disease duration, the ΔHR/ΔSBP-10 min significantly discriminated MSA-COH from PD-COH (P = 0.031). An ΔHR/ΔSBP-10 min of 0.517 showed a sensitivity of 67% and specificity of 84% (AUC = 0.77, 95% CI: 0.63-0.91).

Conclusion

The SBP, diastolic BP, and HR were higher in the supine position; however, ΔHR and ΔSBP were lower after standing in MSA patients than in PD patients. The ΔHR/ΔSBP-10 min discriminated between MSA-COH and PD-COH with quiet acceptable accuracy.

Influencing factors and hemodynamic study of initial and sustained orthostatic hypotension in middle-aged and elderly patients

Orthostatic hypotension (OH) is a common autonomic disorder. This study aimed to investigate the influencing factors and hemodynamic mechanisms of initial and sustained OH in middle-aged and elderly patients. The authors analyzed the clinical characteristics and hemodynamic variables of patients aged ≥ 50 years according to the various forms of OH, diagnosed by an active orthostatic test using the CNAP monitor. The study included 473 participants; 119 (25.2%) patients had initial (54, 45.4%) or sustained (65, 54.6%) OH. Age, comorbidities, or medications did not differ significantly between the initial OH and non-OH groups. Sustained OH was associated with age and diabetes (p = .003 and p = .015, respectively). Hemodynamic analysis revealed higher cardiac output (CO) in the sustained OH group within 15 s than in the non-OH and initial OH groups (both p < .001); no difference in CO was observed between the initial OH and non-OH groups. The systemic vascular resistance (SVR) in both initial OH and sustained OH groups within 15 s was lower than that in the non-OH group (both p < .001). No differences in SVR at 3 min were observed between the initial OH and non-OH groups. The SVR at 3 min in the sustained OH group was significantly lower than in non-OH and initial OH groups (both p < .001). Age and diabetes emerged as the independent risk factors associated with sustained OH. Initial OH is associated with a mismatch of increase in CO and decrease in SVR. Sustained OH is mainly associated with sustained inadequate adjustment in SVR.

Comparison of the sit-up test and head-up tilt test for assessing blood pressure and hemodynamic responses in healthy young individuals

OBJECTIVE

The sit-up test is used to assess orthostatic hypotension, without the use of a tilt table, in populations who are unable to stand. The primary objective of this study was to determine the differences in blood pressure and hemodynamic responses between the sit-up and head-up tilt tests. The secondary objective was to determine the hemodynamic responses related to changes in blood pressure during each test.

METHODS

Nineteen healthy volunteers (nine males, aged 24.3 ± 2.4 years) underwent the sit-up and head-up tilt tests. Systolic and diastolic blood pressure, heart rate, stroke volume, cardiac output, and total peripheral resistance were measured.

RESULTS

The increase in systolic blood pressure (15 ± 9 vs. 8 ± 8 mmHg) was greater, while the increase in heart rate (8 ± 5 vs. 12 ± 8 bpm) and reduction in stroke volume (-17 ± 10 vs. -21 ± 10 ml) were smaller during the sit-up test than during the head-up tilt test (P < 0.05). Additionally, the increases in blood pressure variables were significantly associated with the increase in total peripheral resistance (P < 0.05), but not with changes in other hemodynamic variables in both tests.

CONCLUSION

Although the magnitudes of changes in systolic blood pressure, heart rate, and stroke volume differed between the tests, the hemodynamic variable related to changes in blood pressure was the same for both tests. These results may contribute to the clinical application of the sit-up test for identifying the presence and hemodynamic mechanisms of orthostatic hypotension.

Determinants of orthostatic cerebral oxygenation assessed using near-infrared spectroscopy

BACKGROUND

To understand the relationship between blood pressure changes during standing up and clinical outcome, cerebral oxygenation needs to be measured, which may be performed using near-infrared spectroscopy (NIRS). However, the role of potential determinants of NIRS-derived orthostatic cerebral oxygenation, i.e., age, sex, type of postural change (i.e., standing up from sitting versus supine position), blood pressure (BP) and baroreflex sensitivity (BRS) is still unknown and needed to better interpret findings from studies using orthostatic NIRS measurements.

METHODS

34 younger (median age 25 years, inter quartile range (IQR) 22-45) and 31 older adults (median age 77 years, IQR 72-81) underwent BP, BRS and NIRS measurements during standing up from sitting and supine position. Linear regression models were used to assess the potential determinant role of age, sex, type of postural change, BP and BRS in orthostatic cerebral oxygenation drop and recovery. Orthostatic cerebral oxygenation test-retest reliability was assessed using intra class correlations.

RESULTS

Younger age, male sex and standing up from supine compared to sitting position were positively associated with cerebral oxygenation drop; older age and standing up from sitting compared to supine position were associated with higher cerebral oxygenation recovery. Test-retest reliability was highest (ICC > 0.83) during standing up from supine position.

CONCLUSION

Based on the findings of this study, age, sex and type of postural change are significant determinants of NIRS-derived orthostatic cerebral oxygenation and should be taken into account in the interpretation of NIRS measurements. In the design of new studies, standing up from supine position is preferable (higher reliability) over standing up from sitting position.

Correlation of orthostatic hypotension with extracranial carotid and intracranial cerebral arteries atherosclerosis in patients with acute ischemic stroke under cerebral angiography

OBJECTIVE

The clinical management of patients with acute ischemic stroke (AIS) is complicated by orthostatic hypotension, which might have close relationship with the atherosclerosis of cerebral arteries. The primary objectives were to evaluate the relationship of orthostatic hypotension with extracranial carotid arteries atherosclerosis (ECAS) and intracranial atherosclerosis (ICAS) in AIS patients.

METHODS

This study was a prospective cohort analysis of consecutive AIS patients under cerebrovascular angiography. A total of 289 patients were included. orthostatic hypotension was defined as a systolic BP decline ≥20 mmHg or a diastolic BP decline ≥10 mmHg within 3 min of standing. Univariate and multivariate analysis were performed to investigate the association of the clinical variables with orthostatic hypotension.

RESULTS

Orthostatic hypotension was identified in 80 (27.7%) of all patients. ECAS (≥70%) and ICAS (≥50%) was found in 39 (13.5%) and 71 (24.6%) respectively. In multivariate analysis, only diabetes mellitus (odds ratio = 2.00, 95% confidence interval, 1.12-3.58, P = 0.019) and ECAS (odds ratio = 1.97, 95% confidence interval, 1.54-2.51, P < 0.001) were independent risk factors for orthostatic hypotension.

CONCLUSIONS

Orthostatic hypotension is a relatively common finding among patients with AIS. AIS patients should be screened for orthostatic hypotension, especially combined with severe ECAS and diabetes mellitus.

Clinical clustering of eight orthostatic haemodynamic patterns in The Irish Longitudinal Study on Ageing (TILDA)

BACKGROUND

Orthostatic hypotension (OH) can be assessed with non-invasive continuous beat-to-beat haemodynamic monitoring during active stand (AS) testing; this yields large volumes of data outside the scope of the traditional OH definition. We explored clinical associations of different AS patterns in participants from Wave 1 of the Irish Longitudinal Study on Ageing.

METHODS

AS patterns were generated based on three sequential binary systolic blood pressure features: drop ≥40 mmHg within 10 sec post-stand ("immediate deficit"), failure to return to within 20 mmHg of supine level at 40 sec after standing ("stabilisation deficit") and drop ≥20 mmHg between >40 and 120 sec post-stand ("late deficit"). Eight AS groups resulted from combining the presence/absence of these three features. The groups were cross-sectionally characterised, and their ability to independently predict orthostatic intolerance (OI) during AS, and falls or syncope in the past year, was evaluated using multivariate logistic regression models.

RESULTS

A total of 4,899 participants were included (mean age 61), of which 3,312 (68%) had no deficits. Older age was associated with stabilisation deficit and late deficits were seen in groups with higher proportions of beta blockers and psychotropic medications. Regression models identified independent associations between OI and three immediate-deficit groups; associations seemed stronger as more deficits were present. There was a significant association between falls history and the three-deficit group (odds ratio 1.54, 95% confidence interval: 1.15-2.07, P = 0.004).

CONCLUSIONS

More deficits seemed associated with the higher risk of OI and falls history. Observations are not causal but the recognition of these patterns may help clinicians focus on careful prescribing.

One-Dimensional Statistical Parametric Mapping Identifies Impaired Orthostatic Cerebrovascular and Cardiovascular Response in Frailty Index

Background

Orthostasis is a potent physiological stressor which adapts with age. The age-related accumulation of health deficits in multiple physiological systems may impair the physiological response to orthostasis and lead to negative health outcomes such as falls, depression, and cognitive decline. Research to date has focused on changes with orthostasis at prespecified intervals of time, without consideration for whole signal approaches.

Methods

One-dimensional statistical parametric mapping identified regions in time of significant association between variables of interest using a general linear model. Frailty index operationalized accumulated health and social deficits using 32-items from a computer-assisted interview. This study examined the association of frailty index on blood pressure, heart rate, and cerebral oxygenation during an orthostatic test in a sample of 2742 adults aged 50 or older from The Irish Longitudinal Study on Ageing.

Results

Frailty index was seen to be negatively associated with cerebral oxygenation changes from baseline over a period of 7 seconds (p = .036). Heart rate and systolic blood pressure were positively and negatively associated with frailty index over periods of 17 seconds (p = .001) and 10 seconds (p = .015), respectively.

Conclusions

Statistical parametric mapping demonstrated these significant regions of cerebral oxygenation during orthostasis provide indirect evidence of impaired autoregulation associated with frailty. Statistical parametric mapping also replicated prior relationships in heart rate and systolic blood pressure associated with a higher frailty index. These findings highlight the utility of 1-dimensional statistical parametric modeling in identifying significant regions of interest in physiological recordings.

Delayed Blood Pressure Recovery After Standing Independently Predicts Fracture in Community-Dwelling Older People

OBJECTIVES

Orthostatic hypotension, characterized by delayed blood pressure (BP) recovery after standing, is a risk factor for falls but the longitudinal relationship with fracture is not yet known. The aim of this study was to examine the prospective risk of fracture associated with delayed BP recovery.

DESIGN

Longitudinal study with 8-year follow-up.

SETTING AND PARTICIPANTS

More than 3000 (54% female) community-dwelling people aged ≥50 years from a large longitudinal study on ageing.

METHODS

Orthostatic BP was measured using a finometer when standing from lying. Delayed BP recovery was defined as systolic BP ≥20 mm Hg lower and/or diastolic BP ≥10 mm Hg from the baseline value at 30, 60, and 90 seconds after standing. Participants with a fracture reported at any of waves 2 to 5 were defined as having incident fracture. Logistic regression models were used to estimate odds ratios (ORs) for the association between delayed BP recovery and incident fracture.

RESULTS

Seven percent (212/3117) of participants sustained a fracture during follow-up. Delayed BP recovery at 30 seconds was a significant predictor of any fracture [OR 1.80, 95% confidence interval (CI) 1.28-2.53] and hip fracture (OR 4.44, 95% CI 2.03-9.71) in fully adjusted models. Delayed BP recovery at 30 seconds did not predict wrist or vertebral fracture. Delayed BP recovery at 60 seconds also predicted any fracture (OR 1.74, 95% CI 1.19-2.54) and hip fracture (OR 4.66, 95% CI 2.12-10.26) whereas delayed BP recovery at 90 seconds predicted any (OR 1.99, 95% CI 1.38-2.87), wrist (OR 1.87, 95% CI 1.19-2.95), and hip fracture (OR 3.39, 95% CI 1.45-7.93) in fully adjusted models.

CONCLUSION

and Implications: Delayed BP recovery independently predicts fracture in community-dwelling older people, is potentially modifiable, and can be measured in an ambulatory setting. Because of the morbidity and mortality associated with fractures, identification of such risk factors is crucial in order to inform preventative strategies.

The preponderance of initial orthostatic hypotension in postural tachycardia syndrome

Reduced systolic/diastolic blood pressure (BP) by >40/20 mmHg defines initial orthostatic hypotension (IOH). Rapid resolution of hypotension and lightheadedness follows, but tachycardia may be prolonged. We aimed to examine IOH in controls and patients with postural tachycardia syndrome (POTS) using indices of spontaneous fluctuations of heart rate (HR) and systolic BP as measures of cardiac baroreflex differences. We recruited otherwise healthy IOH patients without POTS (n = 20, 16 ± 3 yr), healthy volunteers (n = 32, 17 ± 3 yr), and POTS patients (n = 39, 17 ± 4 yr). Subjects were instrumented for electrocardiography and beat-to-beat BP. After 10 min supine, subjects stood for 5 min. Following supine recovery, subjects underwent 70° head-up tilt for 10 min to test for POTS. BP, HR, and time, referenced to standing, were measured at events during standing: minimum BP, BP recovery, peak HR, HR minimum, and steady state. Baseline HR and BP were higher in POTS compared with healthy groups. IOH occurred in 13% of controls and 51% of POTS patients. The BP minimum was lower in POTS. Parasympathetic modulation of cardiac baroreflex was decreased in all POTS and control-IOH subjects. Sympathetic indices were increased. Events following BP minimum occurred progressively later in all POTS and control-IOH subjects compared with non-IOH controls. IOH is more frequent in POTS than in controls with a lower minimum BP. POTS has markedly reduced heart rate variability and baroreflex, indicating reduced HR buffering of BP. POTS-IOH and control-IOH subjects had similar peak HR despite decreased minimum BP in POTS. IOH data indicate modest parasympathetic and cardiovagal baroreflex deficits in control-IOH subjects. Parasympathetic deficits are more severe in all POTS patients.NEW & NOTEWORTHY 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.

Orthostatic blood pressure recovery associates with physical performance, frailty and number of falls in geriatric outpatients

Blood pressure (BP) recovery after orthostatic hypotension might be important to prevent cerebral hypoperfusion episodes in older adults, and be related to better clinical outcome. The objective was to study the relationship between BP recovery and clinical outcome, that is physical and cognitive performance, frailty and falls, in geriatric outpatients.

Timing of Circulatory and Neurological Events in Syncope

Syncope usually lasts less than a minute, in which short time arterial blood pressure temporarily falls enough to decrease brain perfusion so much that loss of consciousness ensues. Blood pressure decreases quickest when the heart suddenly stops pumping, which happens in arrhythmia and in severe cardioinhibitory reflex syncope. Loss of consciousness starts about 8 s after the last heart beat and circulatory standstill occurs after 10-15 s. A much slower blood pressure decrease can occur in syncope due to orthostatic hypotension Standing blood pressure can then stabilize at low values often causing more subtle signs (i.e., inability to act) but often not low enough to cause loss of consciousness. Cerebral autoregulation attempts to keep cerebral blood flow constant when blood pressure decreases. In reflex syncope both the quick blood pressure decrease and its low absolute value mean that cerebral autoregulation cannot prevent syncope. It has more protective value in orthostatic hypotension. Neurological signs are related to the severity and timing of cerebral hypoperfusion. Several unanswered pathophysiological questions with possible clinical implications are identified.

Orthostatic hypotension in internal medicine wards

OBJECTIVES

Most studies of orthostatic hypotension (OH) have focused on community-dwelling and institutionalized patient populations. Less is known about OH in hospitalized patients. Moreover, a comprehensive review of OH in internal medicine wards has not been published in the English literature. Our purpose is to provide current information regarding OH in internal medicine inpatients.

METHODS

A comprehensive search of medical databases was performed for potentially relevant articles, using the following keywords: postural or orthostatic hypotension, with the combination of hospitalization or internal medicine. Inclusion criteria were: population of patients hospitalized for acute disorders in internal medicine or geriatric wards with a sample size of ≥50 and publication as an original full-length article in the English language. Data from 14 selected studies are reviewed, including: pathophysiology, evaluation, prevalence, manifestations, risk factors, prognosis, and management.

RESULTS

OH is a common and often symptomatic disorder in elderly internal medicine patients. The prevalence of OH in this population ranges from 22-75%. There are substantial discrepancies between the studies reviewed regarding definitions and means of evaluating OH. OH in internal medicine wards is largely non-neurogenic and multifactorial. The main predisposing factors for OH are prolonged bed rest, hypertension, and heart failure. OH in internal medicine wards is managed mainly with non-pharmacologic interventions, and is frequently reversible.

CONCLUSIONS

In internal medicine inpatients, OH warrants attention because this disorder is common, potentially dangerous, and treatable. In the hospital setting, OH should be routinely assessed on ambulation, following the current guidelines for OH definition and meaning.