Initial orthostatic hypotension among patients with unexplained syncope: An overlooked diagnosis?

Diagnostic and societal impact of implementing the syncope guidelines of the European Society of Cardiology (SYNERGY study)

BACKGROUND

Syncope management is fraught with unnecessary tests and frequent failure to establish a diagnosis. We evaluated the potential of implementing the 2018 European Society of Cardiology (ESC) Syncope Guidelines regarding diagnostic yield, accuracy and costs.

METHODS

A multicentre pre-post study in five Dutch hospitals comparing two groups of syncope patients visiting the emergency department: one before intervention (usual care; from March 2017 to February 2019) and one afterwards (from October 2017 to September 2019). The intervention consisted of the simultaneous implementation of the ESC Syncope Guidelines with quick referral routes to a syncope unit when indicated. The primary objective was to compare diagnostic accuracy using logistic regression analysis accounting for the study site. Secondary outcome measures included diagnostic yield, syncope-related healthcare and societal costs. One-year follow-up data were used to define a gold standard reference diagnosis by applying ESC criteria or, if not possible, evaluation by an expert committee. We determined the accuracy by comparing the treating physician's diagnosis with the reference diagnosis.

RESULTS

We included 521 patients (usual care, n = 275; syncope guidelines intervention, n = 246). The syncope guidelines intervention resulted in a higher diagnostic accuracy in the syncope guidelines group than in the usual care group (86% vs.69%; risk ratio 1.15; 95% CI 1.07 to 1.23) and a higher diagnostic yield (89% vs. 76%, 95% CI of the difference 6 to 19%). Syncope-related healthcare costs did not differ between the groups, yet the syncope guideline implementation resulted in lower total syncope-related societal costs compared to usual care (saving €908 per patient; 95% CI €34 to €1782).

CONCLUSIONS

ESC Syncope Guidelines implementation in the emergency department with quick referral routes to a syncope unit improved diagnostic yield and accuracy and lowered societal costs.

TRIAL REGISTRATION

Netherlands Trial Register, NTR6268.

Objective Hemodynamic Cardiovascular Autonomic Abnormalities in Post-Acute Sequelae of COVID-19

BACKGROUND

Many COVID-19 patients are left with symptoms several months after resolution of the acute illness; this syndrome is known as post-acute sequalae of COVID-19 (PASC). We aimed to determine the prevalence of objective hemodynamic cardiovascular autonomic abnormalities (CAA), explore sex differences, and assess the prevalence of CAA among hospitalized vs nonhospitalized patients with PASC.

METHODS

Patients with PASC (n = 70; female [F] = 56; 42 years of age; 95% confidence interval [CI], 40-48) completed standard autonomic tests, including an active stand test 399 days (338, 455) after their COVID-19 infection. Clinical autonomic abnormalities were evaluated.

RESULTS

Most patients with PASC met the criteria for at least 1 CAA (51; 73%; F = 43). The postural orthostatic tachycardia syndrome hemodynamic (POTSHR) criterion of a heart rate increase of > 30 beats per minute within 5 to 10 minutes of standing was seen in 21 patients (30%; F = 20; P = 0.037 [by sex]). The initial orthostatic hypotension hemodynamic (IOH40) criterion of a transient systolic blood pressure change of > 40 mm Hg in the first 15 seconds of standing was seen in 43 (61%) patients and equally among female and male patients (63% vs 57%; P = 0.7). Only 9 (13%) patients were hospitalized; hospitalized vs nonhospitalized patients had similar frequencies of abnormalities (67% vs 74%; P = 0.7).

CONCLUSIONS

Patients with PASC have evidence of CAA, most commonly IOH40, which will be missed unless an active stand test is used. Female patients have increased frequency of POTSHR, but IOH40 is equally prevalent between sexes. Finally, even nonhospitalized "mild" infections can result in long-term CAAs.

Syncope Diagnosis at Referral to a Tertiary Syncope Unit: An in-Depth Analysis of the FAST II

OBJECTIVE

A substantial number of patients with a transient loss of consciousness (T-LOC) are referred to a tertiary syncope unit without a diagnosis. This study investigates the final diagnoses reached in patients who, on referral, were undiagnosed or inaccurately diagnosed in secondary care.

METHODS

This study is an in-depth analysis of the recently published Fainting Assessment Study II, a prospective cohort study in a tertiary syncope unit. The diagnosis at the tertiary syncope unit was established after history taking (phase 1), following autonomic function tests (phase 2), and confirming after critical follow-up of 1.5-2 years, with the adjudicated diagnosis (phase 3) by a multidisciplinary committee. Diagnoses suggested by the referring physician were considered the phase 0 diagnosis. We determined the accuracy of the phase 0 diagnosis by comparing this with the phase 3 diagnosis.

RESULTS

51% (134/264) of patients had no diagnosis upon referral (phase 0), the remaining 49% (130/264) carried a diagnosis, but 80% (104/130) considered their condition unexplained. Of the patients undiagnosed at referral, three major causes of T-LOC were revealed: reflex syncope (69%), initial orthostatic hypotension (20%) and psychogenic pseudosyncope (13%) (sum > 100% due to cases with multiple causes). Referral diagnoses were either inaccurate or incomplete in 65% of the patients and were mainly altered at tertiary care assessment to reflex syncope, initial orthostatic hypotension or psychogenic pseudosyncope. A diagnosis of cardiac syncope at referral proved wrong in 17/18 patients.

CONCLUSIONS

Syncope patients diagnosed or undiagnosed in primary and secondary care and referred to a syncope unit mostly suffer from reflex syncope, initial orthostatic hypotension or psychogenic pseudosyncope. These causes of T-LOC do not necessarily require ancillary tests, but can be diagnosed by careful history-taking. Besides access to a network of specialized syncope units, simple interventions, such as guideline-based structured evaluation, proper risk-stratification and critical follow-up may reduce diagnostic delay and improve diagnostic accuracy for syncope.

Diagnosis and treatment of orthostatic hypotension

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

Mitigating Initial Orthostatic Hypotension: Mechanistic Roles of Muscle Contraction Versus Sympathetic Activation

BACKGROUND

Initial orthostatic hypotension (IOH) is defined by a large drop in blood pressure (BP) within 15 s of standing. IOH often presents during an active stand, but not with a passive tilt, suggesting that a muscle activation reflex involving lower body muscles plays an important role. To our knowledge, there is no literature exploring how sympathetic activation affects IOH. We hypothesized involuntary muscle contractions before standing would significantly reduce the drop in BP seen in IOH while increasing sympathetic activity would not.

METHODS

Study participants performed 4 sit-to-stand maneuvers including a mental stress test (serial 7 mental arithmetic stress test), cold pressor test, electrical stimulation, and no intervention. Continuous heart rate and beat-to-beat BP were measured. Cardiac output and systemic vascular resistance were estimated from these waveforms. Data are presented as mean±SD.

RESULTS

A total of 23 female IOH participants (31±8 years) completed the study. The drops in systolic BP following the serial 7 mental arithmetic stress test (-26±12 mm Hg; P=0.004), cold pressor test (-20±15 mm Hg; P<0.001), and electrical stimulation (-28±12 mm Hg; P=0.01) were significantly reduced compared with no intervention (-34±11 mm Hg). The drops in systemic vascular resistance following the serial 7 mental arithmetic stress test (-391±206 dyne×s/cm⁵; P=0.006) and cold pressor test (-386±179 dyne×s/cm⁵; P=0.011) were significantly reduced compared with no intervention (-488±173 dyne×s/cm⁵). Cardiac output was significantly increased upon standing (7±2 L/min) compared with during the sit (6±1 L/min; P<0.001) for electrical stimulation.

CONCLUSION

Sympathetic activation mitigates the BP response in IOH, while involuntary muscle contraction mitigates the BP response and reduces symptoms. Active muscle contractions may induce both of these mechanisms of action in their pretreatment of IOH. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03970551.

Feasibility of Diagnosing Initial Orthostatic Hypotension Using a Continuous Blood Pressure Device in Geriatric Rehabilitation Inpatients: RESORT

Background

Initial orthostatic hypotension (IOH) is highly prevalent in older adults and may interfere with the ability to regain function after acute hospitalization. IOH assessment requires a non-invasive, beat-to-beat continuous blood pressure device, which is not widely used in geriatric rehabilitation. Our aim was to test the feasibility of diagnosing IOH using a continuous blood pressure device in geriatric rehabilitation inpatients.

Methods

Geriatric rehabilitation inpatients of the REStORing Health of Acutely Unwell AdulTs (RESORT) cohort admitted to a tertiary hospital were randomly selected to undergo continuous blood pressure monitoring (Finapres) for 5 min in the supine position and 3 min of standing or sitting when unable to stand. Interventions to warm hands and adjusting the cuff pressure sizes were attempted if no signal was obtained or an error message occurred.

Results

Of 37 randomly selected inpatients, 29 {55.2% female; mean age 82.8 (standard deviation [SD]) 6.6 years} agreed to the continuous blood pressure measurement. Successful measurements were achieved in 20 out of 29 inpatients, two after hand warming. Patients with unsuccessful measurements were likely to be older (mean age 87.2 [SD] 4.4 years, p = 0.03), have cerebrovascular disease (p = 0.006), lower body mass index (p = 0.012), and a lower short physical performance battery score (p = 0.039). Eight out of 20 patients had IOH.

Conclusion

The number of unsuccessful continuous blood pressure measurements was high in a population with high IOH prevalence despite multiple interventions to establish a signal. Future research should focus on improving the efficiency of continuous blood pressure devices in hospitalized patients with unsuccessful signals.

Diagnostic criteria for initial orthostatic hypotension: a narrative review

Abnormalities in orthostatic blood pressure changes upon active standing are associated with morbidity, mortality, and reduced quality of life. However, over the last decade, several population-based cohort studies have reported a remarkably high prevalence (between 25 and 70%) of initial orthostatic hypotension (IOH) among elderly individuals. This has raised the question as to whether the orthostatic blood pressure patterns in these community-dwelling elderly should truly be considered as pathological. If not, redefining of the systolic cutoff values for IOH (i.e., a value ≥ 40 mmHg in systolic blood pressure in the first 15 s after standing up) might be necessary to differ between normal aging and true pathology. Therefore, in this narrative review, we provide a critical analysis of the current reference values for the changes in systolic BP in the first 60 s after standing up and discuss how these values should be applied to large population studies. We will address factors that influence the magnitude of the systolic blood pressure changes following active standing and the importance of standardization of the stand-up test, which is a prerequisite for quantitative, between-subject comparisons of the postural hemodynamic response.

Prevalence of initial orthostatic hypotension in older adults: a systematic review and meta-analysis

Background

Initial orthostatic hypotension (OH) is a clinical syndrome of exaggerated transient orthostasis associated with higher risks of falls, frailty and syncope in older adults.

Objective

To provide a prevalence estimate of initial OH in adults aged 65 years or older.

Methods

Literature search of MEDLINE (from 1946), Embase (from 1947) and Cochrane Central Register of Controlled Trials was performed until 6 December 2019, using the terms ‘initial orthostatic hypotension’, ‘postural hypotension’ and ‘older adults’. Articles were included if published in English and participants were 65 years or older. Random effects models were used for pooled analysis.

Results

Of 5,136 articles screened, 13 articles (10 cross-sectional; 3 longitudinal) reporting data of 5,465 individuals (54.5% female) from the general (n = 4,157), geriatric outpatient (n = 1,136), institutionalised (n = 55) and mixed (n = 117) population were included. Blood pressure was measured continuously and intermittently in 11 and 2 studies, respectively. Pooled prevalence of continuously measured initial OH was 29.0% (95% CI: 22.1–36.9%, I² = 94.6%); 27.8% in the general population (95% CI: 17.9–40.5%, I² = 96.1%), 35.2% in geriatric outpatients (95% CI: 24.2–48.1%, I² = 95.3%), 10.0% in institutionalised individuals (95% CI: 2.4–33.1%, I² = 0%) and 21.4% in the mixed population (95% CI: 7.0–49.6, I² = 0%). Pooled prevalence of intermittently measured initial OH was 5.6% (95% CI: 1.5–18.9%, I² = 81.1%); 1.0% in the general population (95% CI: 0.0–23.9%, I² = 0%) and 7.7% in geriatric outpatients (95% CI: 1.8–27.0%, I² = 86.7%).

Conclusion

The prevalence of initial OH is high in older adults, especially in geriatric outpatients. Proper assessment of initial OH requires continuous blood pressure measurements.

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.

Systemic and cerebral circulatory adjustment within the first 60 s after active standing: An integrative physiological view

Transient cardiovascular and cerebrovascular responses within the first minute of active standing provide the means to assess autonomic, cardiovascular and cerebrovascular regulation using a real-world everyday stimulus. Traditionally, these responses have been used to detect autonomic dysfunction, and to identify the hemodynamic correlates of patient symptoms and attributable causes of (pre)syncope and falls. This review addresses the physiology of systemic and cerebrovascular adjustment within the first 60 s after active standing. Mechanical factors induced by standing up cause a temporal mismatch between cardiac output and vascular conductance which leads to an initial blood pressure drops with a nadir around 10 s. The arterial baroreflex counteracts these initial blood pressure drops, but needs 2-3 s to be initiated with a maximal effect occurring at 10 s after standing while, in parallel, cerebral autoregulation buffers these changes within 10 s to maintain adequate cerebral perfusion. Interestingly, both the magnitude of the initial drop and these compensatory mechanisms are thought to be quite well-preserved in healthy aging. It is hoped that the present review serves as a reference for future pathophysiological investigations and epidemiological studies. Further experimental research is needed to unravel the causal mechanisms underlying the emergence of symptoms and relationship with aging and adverse outcomes in variants of orthostatic hypotension.

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.

Orthostatic change in systolic blood pressure associated with cold pressor reflection and heart rate variability in the elderly

Background: Impaired orthostatic blood pressure (BP) response is a frequent finding in the elderly. The goal of the study was to investigate the association of variability of supine-to-orthostatic BP with cold pressor reflection and heart rate variability in the elderly.Methods: From June 2010 to September 2013, 287 elderly aged ≥ 60 years were enrolled in Jinan area, China. The elderly were classified into lower (n = 96), intermediate (n = 95), and higher (n = 96) tertile groups according to the tertile of the percentage change of supine-to-orthostatic systolic BP.Results: There were significant increasing trends in systolic BP response to the CPT at 0 and 60 sec; the plasma levels of epinephrine, norepinephrine, and angiotensin II; and decreasing trends in DNN, SDNN index, and SDANN from the lower to the higher tertile group, and differences between any two groups were significant (P < .05). The percentage change of supine-to-orthostatic systolic BP was positively correlated with systolic BP response to CPT at 0 and 60 sec, VLF, epinephrine, norepinephrine, and angiotensin II (P < .001) and negatively correlated with SDNN, SDNN index, SDANN, rMSSD, pNN50, LF, and ratio of LF/HF (P < .001). The BP response to CPT, parameters of HRV, and the plasma levels of norepinephrine and angiotensin II were independently associated with the percentage change of supine-to-orthostatic systolic BP after adjustment for confounders.Conclusion: Aggressive variability of supine-to-orthostatic systolic BP might be significantly associated with the imbalance of sympathetic and parasympathetic activity, especially high sensitivity sympathetic response in the elderly.Abbreviations: BP: blood pressure; BMI: body mass index; CPT: cold pressor test; HRV: heart rate variability; SDNN: standard deviation of all normal-to-normal R-R intervals; SDNN index: mean of the standard deviations of all 5-min normal-to-normal R-R intervals of the entire recording; SDANN: standard deviation of the averages of normal-to-normal R-R intervals during all 5-min periods of the entire recording; rMSSD: square root of the mean squared differences between successive normal R-R intervals; pNN50: number of adjacent normal R-R intervals differing by more than 50 ms; VLF: very low frequency; LF: low frequency; HF: high frequency; TCHO: total cholesterol; HDL-c: high-density lipoprotein cholesterol; LDL-c: low-density lipoprotein cholesterol; FPG: fasting plasma glucose; SD: standard deviation.

Neurogenic Orthostatic Hypotension in Parkinson Disease: A Primer

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