Developing pulmonary vasculopathy in systemic sclerosis, detected with non-invasive cardiopulmonary exercise testing

Validation of Air Storage System for Hypoxia Exposure During Exercise

Norberto, Matheus S., João Victor G. Torini, Matheus S. Firmino, and Marcelo Papoti. Validation of air storage system for hypoxia exposure during exercise. High Alt Med Biol. 00:000-000, 2024.-Considering the importance of optimizing normobaric hypoxia exposure (i.e., higher delivery capacity), the current study aims to validate a hypoxic air storage system. The study has a cross-over, one-blind randomized design. The air storage is composed of a piping system that directs hypoxic air from a hypoxia generator into nylon bags. Sixteen men (age, 25.4 ± 4.8 years; height, 174.9 ± 9.4 cm; weight, 77.1 ± 17.2 kg) performed three incremental treadmill tests until exhaustion on different days. For test-retest, the subjects repeated two tests in similar hypoxia conditions (H1 and H2; fraction of inspired O2 [FIO2] = ∼0.13; reliability analysis), and one time in normoxia (FIO2 = ∼0.20; condition comparison). Subjects' performance, blood lactate concentration ([La-]), arterial oxygen saturation (SpO2), oxygen consumption (VO2), heart rate (HR), and several respiratory-derived variables were evaluated. A comparison was made between the rest, moderate intensity, and exhaustion stages. All variables were compared using the Friedman test with Durbin-Conover post hoc (p < 0.05). The hypoxia test-retest showed no statistical differences for any variable. Time analysis showed similar behavior for SpO2, HR, and cardiorespiratory variables (p < 0.01) for both conditions. The mean FIO2 at rest and during the incremental treadmill test was higher for normoxia (20.6 ± 0.2%) than for H1 (13.8 ± 0.8%) and H2 (13.7 ± 0.3%) (p < 0.001). The VO2 response was higher in normoxia than during hypoxia exposure at moderate intensity (Normoxia = 43.1 ± 8.1; H1 = 38.7 ± 5.7; H2 = 35.8 ± 8.8 ml.kg-1.min-1) and at the exhaustion stage (Normoxia = 52.7 ± 12.5; H1 = 41.9 ± 8.8; H2 = 40.5 ± 8.9 ml.kg-1.min-1) (p < 0.01). SpO2 and HR showed excellent intraclass correlation coefficient (ICC) during all moments, whereas VO2, SpO2, ratio between ventilation and CO2 production (VE/VCO2), ratio between oxygen consumption and ventilation (VE/VO2), and HR showed moderate or good ICC and coefficient of variation <9% during hypoxia test-retest exercises. Thus, the air storage system showed validity for its application and reliability in the measurements associated.

Use of exercise tests in screening for pulmonary arterial hypertension in systemic sclerosis: A systematic literature review

Background and objective

Patients with systemic sclerosis (SSc) and pulmonary arterial hypertension (PAH) have a poor prognosis, accounting for 30% of all SSc-related deaths. Guidelines recommend annual screening for PAH regardless of symptoms, as early treatment improves outcomes. Current protocols include combinations of clinical features, biomarkers, pulmonary function tests, and echocardiography. None include exercise testing, although early-stage PAH may only be evident during exercise. This systematic review assessed the performance of exercise tests in predicting the presence of PAH in patients with SSc, where PAH was confirmed through right heart catheterisation (RHC).

Methods

Comprehensive literature searches were performed using MEDLINE, EMBASE, Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trails, CINAHL, Scopus and Web of Science from inception to May 2023. Articles were screened for eligibility by two independent reviewers. Eligibility criteria included the use of a non-invasive exercise test to screen adult patients to detect PAH in a population without a previous diagnosis of PAH, with diagnosis confirmed by RHC.

Results

Eight studies met the inclusion criteria, describing at least one of three different non-invasive exercise tests: cardiopulmonary exercise test, six-minute walk test and stress Doppler echocardiography. All studies found that exercise tests had some ability to predict the presence of PAH, with sensitivity between 50% and 100% and specificity from 73% to 91%.

Conclusion

Exercise tests are infrequently used for screening for PAH in SSc but can predict the presence of PAH. More data are required to establish which tests are most effective.

Disease specific determinants of cardiopulmonary fitness in systemic sclerosis

OBJECTIVES

We aimed to quantify the burden of exercise intolerance in systemic sclerosis (SSc) and explore the disease features that contribute to impaired exercise capacity (measured as peak oxygen uptake, peak VO₂) to provide novel mechanistic insights into the causes of physical disability in SSc.

METHODS

Thirty-three SSc patients with no history of cardiac disease and no active myositis underwent cardiac and skeletal muscle MRI, transthoracic echocardiography, pulmonary function tests and cardiopulmonary exercise testing (CPET). CPET results were compared to an age-, sex-, and weight-matched controls with no overt cardiopulmonary disease. Native T1 and T2-mapping sequences were used to quantify diffuse fibroinflammatory myocardial disease and qualitative assessment of skeletal muscle oedema was performed. The associations between parameters of cardiorespiratory function and skeletal muscle abnormalities and peak VO₂ were evaluated with linear regression analysis.

RESULTS

Exercise capacity was markedly impaired in SSc and significantly reduced when compared to control subjects (percent predicted peak VO₂: 70% vs 98%, p < 0⋅01). Diffuse myocardial fibroinflammatory disease (p < 0⋅01) and skeletal muscle oedema (p = 0⋅01) were significantly associated with reduced exercise capacity. There was no association between impaired exercise capacity and left ventricular ejection fraction.

CONCLUSION

SSc is associated with marked functional impairment that is not explained by commonly used parameters of cardiac function such as left ventricular ejection fraction. Rather, only more sensitive measures of organ involvement are associated with impaired exercise tolerance. Our results show diffuse interstitial changes of the myocardium and skeletal muscle affect oxygen uptake and are important contributors to functional limitation in SSc.

Variation of PetCO2 during incremental exercise and severity of IPAH and CTEPH

Background and objective

End-tidal PCO₂ (PetCO₂) patterns during exercise testing as well as ventilatory equivalents for CO₂ have been reported for different pulmonary vascular diseases but seldomly for the significant differences in exercise response depending on the etiology of pulmonary hypertension. We aimed to compare PetCO₂ change pattern in IPAH and CTEPH with varying severity during incremental cardiopulmonary exercise testing (CPET).

Methods

164 IPAH patients and 135 CTEPH patients referred to Shanghai Pulmonary Hospital between 2012 and 2019 were retrospectively recruited into the study. All patients performed CPET and also underwent right-heart catheterization (RHC). Forty-four healthy subjects also performed CPET and were included as controls.

Results

PetCO₂ was significantly lower in IPAH and CTEPH patients as compared to normal subjects. Moreover, the PetCO₂ did not rise, in fact fell from rest to anaerobic threshold (AT), then further decreased until peak in both IPAH and CTEPH. PetCO₂ value at rest, unloaded, AT and peak were proportionately reduced as the World Health Organization functional class (WHO-Fc) increased in both IPAH and CTEPH patients. The PETCO₂ in IPAH patients had significant differences during all phases of exercise between WHO-Fc I-II and III-IV subgroup. CTEPH also demonstrated significant difference except for PetCO₂ at peak. PetCO₂ values were significantly higher in IPAH during all phases of exercise as compared to CTEPH patients (all P < 0.001).

PeakVO₂%pred correlated significantly with PetCO₂ at rest (r = 0.477, P < 0.001), AT (r = 0.609, P < 0.001) and peak exercise (r = 0.576, P < 0.001) in IPAH. N-terminal natriuretic peptide type-B (NT-proBNP) also correlated markedly with PetCO₂, with a correlation coefficient of − 0.326 to − 0.427 (all P < 0.001). Additionally, PetCO₂ at rest, at AT and at peak correlated positively with peakVO₂%pred and showed an inverse correlation with NT-proBNP in CTEPH patients (all P < 0.05).

Conclusions

PetCO₂ during exercise in IPAH and CTEPH patients was significantly different from normal subjects. Moreover, PetCO₂ values were significantly higher in IPAH during all phases of exercise as compared to CTEPH patients (all P < 0.001). PetCO₂ was progressively more abnormal with increasing disease severity according to peakVO₂%pred and WHO-Fc.

[Cardiopulmonary exercise testing in the management of systemic sclerosis]

Cardiopulmonary complications are the leading cause of mortality in patients with systemic sclerosis (SSc) requiring an early identification. The complexity of the overlapping aetiologies of dyspnoea in SSc often requires a global and comprehensive approach. Through its integrative approach of ventilatory, metabolic, cardiovascular, skeletal muscular and gas exchange findings, cardiopulmonary exercise testing (CPET) has been known to identify and sort competing mechanisms of exercise limitation in scleroderma patients presenting with dyspnoea. CPET may be used to screen for pulmonary arterial hypertension, suspect interstitial lung disease and guide therapeutic strategies including exercise rehabilitation. This review focuses on the clinical value of CPET in the decision-making processes for a more personalised diagnostic approach to SSc-related complications.

Value of Cardiopulmonary Exercise Testing in Prognostic Assessment of Patients with Interstitial Lung Diseases

BACKGROUND

Interstitial lung disease (ILD) is associated with high rates of comorbidities and non-infectious lung disease mortality. Against this background, we aimed to evaluate the prognostic capacity of lung function and cardiopulmonary exercise testing (CPET) in patients with ILD.

MATERIALS AND METHODS

A total of 183 patients with diverse ILD entities were included in this monocentric analysis. Prediction models were determined using Cox regression models with age, sex, body mass index (BMI), and all parameters from pulmonary function testing and CPET. Kaplan-Meier curves were plotted for selected variables.

RESULTS

The median follow-up period was 3.0 ± 2.5 years. Arterial hypertension (57%) and pulmonary hypertension (38%) were the leading comorbidities. The Charlson comorbidity index score was 2 ± 2 points. The 3-year and 5-year survival rates were 68% and 50%, respectively. VO₂peak (mL/kg/min or %pred.) was identified as a significant prognostic parameter in patients with ILD. The cut-off value for discriminating mortality was 61%.

CONCLUSION

The present analyses consistently revealed the high prognostic power of VO₂peak %pred. and other parameters evaluating breathing efficacy (VÉ/VCO₂ @AT und VÉ/VCO₂ slope) in ILD patients. VO₂peak %pred., in contrast to the established prognostic values FVC %pred., DLCO/KCO %pred., and GAP, showed an even higher prognostic ability in all statistical models.

Cardiopulmonary exercise testing in interstitial lung diseases and the value of ventilatory efficiency

Interstitial lung diseases (ILDs) are diverse parenchymal pulmonary disorders, primarily characterised by alveolar and interstitial inflammation and/or fibrosis, and sharing pathophysiological similarities. Thus, patients generally harbour common respiratory symptoms, lung function abnormalities and modified exercise adaptation. The most usual and disabling complaint is exertional dyspnoea, frequently responsible for premature exercise interruption. Cardiopulmonary exercise testing (CPET) is increasingly used for the clinical assessment of patients with ILD. This is because exercise performance or dyspnoea on exertion cannot reliably be predicted by resting pulmonary function tests. CPET, therefore, provides an accurate evaluation of functional capacity on an individual basis. CPET can unmask anomalies in the integrated functions of the respiratory, cardiovascular, metabolic, peripheral muscle and neurosensory systems in ILDs. CPET uniquely provides an evaluation of all above aspects and can help clinicians shape ILD patient management. Preliminary evidence suggests that CPET may also generate valuable prognostic information in ILDs and can be used to shed light on the presence of associated pulmonary hypertension. This review aims to provide comprehensive and updated evidence concerning the clinical utility of CPET in ILD patients, with particular focus on the physiological and clinical value of ventilatory efficiency (V˙_E/V˙_CO2 ).

Cardiopulmonary exercise testing and prognosis in patients with systemic sclerosis without baseline pulmonary hypertension: a prospective cohort study

Cardiopulmonary Exercise Testing (CPET) is a standardized, non-invasive procedure assessing pulmonary, cardiovascular, hematopoietic, and skeletal muscle functions during a symptom-limited test. Few studies have examined whether CPET is of prognostic value in Systemic Sclerosis (SSc), a disease characterized by highly increased cardiorespiratory morbidity and mortality. To examine the prognostic value of CPET in SSc patients without baseline pulmonary hypertension (PH). Sixty-two consecutive SSc patients underwent CPET, Pulmonary Function Tests (PFTs) and echocardiography at baseline. Four patients with Right Ventricular Systolic Pressure ≥ 40 mmHg, were excluded. Participants repeated PFTs approximately every 3 years. At the end of the follow-up period [median (IQR): 9.79 (2.78) years] patient vital status was recorded. Cox Regression analysis was used to identify predictors of deterioration of PFTs and 10-year survival. Median (IQR) age of 58 patients (90% women) at baseline was 54.0 (15.0) years, whereas 10-year survival was 88%. Baseline respiratory Oxygen uptake (VO₂max) predicted PFT deterioration, defined either as a decline in FVC ≥ 10% or a combined decline in FVC 5%-9% plus DLCO ≥ 15%, during follow-up, after correction for age, gender and smoking status (HR: 0.874, 95%CI: 0.779-0.979, p = 0.021). In addition, lower baseline VO₂max (HR = 0.861, 95%CI:0.739-1.003, p = 0.054) and DLCO (HR = 0.957, 95%CI: 0.910-1.006 p = 0.088), as well as male gender (HR = 5.68, 95%CI: 1.090-29.610 p = 0.039) and older age (HR = 1.069, 95%CI: 0.990-1.154, p = 0.086) were associated, after adjustment, with an increased risk for death. In the absence of baseline PH, CPET indices may predict pulmonary function deterioration and death in SSc patients during a nearly 10-year follow-up period.

[Current Aspects of Definition and Diagnosis of Pulmonary Hypertension]

At the 6th World Symposium on Pulmonary Hypertension (WSPH), which took place from February 27 until March 1, 2018 in Nice, scientific progress over the past 5 years in the field of pulmonary hypertension (PH) was presented by 13 working groups. The results of the discussion were published as proceedings towards the end of 2018. One of the major changes suggested by the WSPH was the lowering of the diagnostic threshold for PH from ≥ 25 to > 20 mmHg mean pulmonary arterial pressure, measured by right heart catheterization at rest. In addition, the pulmonary vascular resistance was introduced into the definition of PH, which underlines the importance of cardiac output determination at the diagnostic right heart catheterization.In this article, we discuss the rationale and possible consequences of a changed PH definition in the context of the current literature. Further, we provide a current overview on non-invasive and invasive methods for diagnosis, differential diagnosis, and prognosis of PH, including exercise tests.

Cardiopulmonary exercise testing in a combined screening approach to individuate pulmonary arterial hypertension in systemic sclerosis

Objectives

The DETECT algorithm has been developed to identify SSc patients at risk for pulmonary arterial hypertension (PAH) yielding high sensitivity but low specificity, and positive predictive value. We tested whether cardiopulmonary exercise testing (CPET) could improve the performance of the DETECT screening strategy.

Methods

Consecutive SSc patients over a 30-month period were screened with the DETECT algorithm and positive subjects were referred for CPET before the execution of right-heart catheterization. The predictive performance of CPET on top of DETECT was evaluated and internally validated via bootstrap replicates.

Results

Out of 314 patients, 96 satisfied the DETECT application criteria and 54 were positive. PAH was ascertained in 17 (31.5%) and pre-capillary pulmonary hypertension in 23 (42.6%) patients. Within CPET variables, the slope of the minute ventilation to carbon dioxide production relationship (VE/VCO₂ slope) had the best performance to predict PAH at right-heart catheterization [median (interquartile range) of specificity 0.778 (0.714–0.846), positive predictive value 0.636 (0.556–0.750)]; exploratory analysis on pre-capillary yielded a specificity of 0.714 (0.636–0.8) and positive predictive value of 0.714 (0.636–0.8).

Conclusion

In association with the DETECT algorithm, CPET may be considered as a useful tool in the workup of SSc-related pulmonary hypertension. The sequential determination of the VE/VCO₂ slope in DETECT-positive subjects may reduce the number of unnecessary invasive procedures without any loss in the capability to capture PAH. This strategy had also a remarkable performance in highlighting the presence of pre-capillary pulmonary hypertension.

Prognostic value of cardiopulmonary exercise testing in patients with systemic sclerosis

Background

Systemic sclerosis (SSc) is a severe rheumatic disease of the interstitial tissue, in which heart and lung involvement can lead to disease-specific mortality. Our study tests the hypothesis that in addition to established prognostic factors, cardiopulmonary exercise testing (CPET) parameters, particularly peak oxygen uptake (peakVO₂) and ventilation/carbon dioxide (VE/VCO₂)-slope, can predict survival in patients with SSc.

Subjects and methods

We retrospectively assessed 210 patients (80.9% female) in 6 centres over 10 years with pulmonary testing and CPET. Survival was analysed with Cox regression analysis (adjusted for age and gender) by age, comorbidity (Charlson-Index), body weight, body-mass index, extensive interstitial lung disease, pulmonary artery pressure (measured by echocardiography and invasively), and haemodynamic, pulmonary and CPET parameters.

Results

Five- and ten-year survival of SSc patients was 93.8 and 86.9%, respectively. There was no difference in survival between patients with diffuse (dcSSc) and limited cutaneous manifestation (lcSSc; p = 0.3). Pulmonary and CPET parameters were significantly impaired. Prognosis was worst for patients with pulmonary hypertension (p = 0.007), 6-min walking distance < 413 m (p = 0.003), peakVO₂ < 15.6 mL∙kg^− 1∙min^− 1, and VE/VCO₂-slope > 35. Age (hazard ratio HR = 1.23; 95% confidence interval CI: 1.14;1.41), VE/VCO₂-slope (HR = 0.9; CI 0.82;0.98), diffusion capacity (Krogh factor, HR = 0.92; CI 0.86;0.98), forced vital capacity (FVC, HR = 0.91; CI 0.86;0.96), and peakVO₂ (HR = 0.87; CI 0.81;0.94) were significantly linked to survival in multivariate analyses (Harrell’s C = 0.95).

Summary

This is the first large study with SSc patients that demonstrates the prognostic value of peakVO₂ < 15.6 mL∙kg^− 1∙min^− 1 (< 64.5% of predicted peakVO₂) and VE/VCO₂-slope > 35.

A review of exercise pulmonary hypertension in systemic sclerosis

In general, pulmonary vascular disease has important negative prognostic implications, regardless of the associated condition or underlying mechanism. In this regard, systemic sclerosis is of particular interest as it is the most common connective tissue disease associated with pulmonary hypertension, and a well-recognized at-risk population. In the setting of systemic sclerosis and unexplained dyspnea, the concept of using exercise to probe for underlying pulmonary vascular disease has acquired significant interest. In theory, a diagnosis of systemic sclerosis-associated exercise pulmonary hypertension may allow for earlier therapeutic intervention and a favorable alteration in the natural history of the pulmonary vascular disease. In the context of underlying systemic sclerosis, the purpose of this article is to provide a comprehensive review of the evolving definition of exercise pulmonary hypertension, the current role and methodologies for non-invasive and invasive exercise testing, and the importance of the right ventricle.

[Functional diagnostics in pneumology]

Alongside imaging techniques, pulmonary function testing helps in the diagnosis of underlying disorders such as asthma and chronic obstructive pulmonary disease (COPD) or fibrosing lung disease. However, disease severity grading is also important, as well as disease follow-up under therapy. The value of spirometry as a first-line diagnostic test, whole-body plethysmography in advanced diagnostics, the measurement of transfer factor, as well as blood gas analysis are outlined. The importance of spiroergometry, echocardiography, and right-heart catheterization, particularly in the functional assessment of pulmonary vascular disorders, is described. Tests in respiratory sleep medicine, such as polysomnography, as well as tests for diagnosing chronic respiratory failure, are part of the respiratory physician's diagnostic armamentarium.

Limited Exercise Capacity in Patients with Systemic Sclerosis: Identifying Contributing Factors with Cardiopulmonary Exercise Testing

Objective.

Exercise limitation in patients with systemic sclerosis (SSc) is often multifactorial and related to complications such as interstitial lung disease (ILD), pulmonary vasculopathy (PV), left ventricular dysfunction (LVD), and/or peripheral/muscular limitation (PML). We hypothesized that cardiopulmonary exercise testing (CPET) could not only suggest and rank competing etiologies, but also highlight peripheral impairment.

Methods.

Clinical, resting pulmonary function testing, and CPET data from patients with SSc referred for exercise limitation between October 2009 and November 2015 were retrospectively analyzed in this bi-center study. Patients were categorized as having ILD, PV, LVD, and/or PML based on CPET response patterns and the diagnoses were matched with results from the reference investigations. The latter consisted of transthoracic echocardiography, chest computed tomography scan, and right heart catheterization (RHC).

Results.

Twenty-seven patients presented with CPET profiles consistent with ILD (n = 16), PV (n = 15), LVD (n = 5), and PML (n = 19). None of the subjects had a normal CPET profile. There was a statistically significant negative correlation between resting DLCO, on the one hand, and dead space to tidal volume ratio and alveolar–arterial gradient [P(Ai-a)O2] on the other (p < 0.005). CPET identified 90% of patients with a mean pulmonary arterial pressure at rest ≥ 21 mmHg measured by RHC (n = 10). Peak P(Ai-a)O2, taken independently from other variables, was crucial in distinguishing subjects with ILD from those without ILD (p < 0.05).

Conclusion.

CPET is useful for the characterization of multifactorial exercise limitation in patients with SSc and in identifying SSc-related complications such as ILD and PV. This study also identifies PML as an underestimated cause of exercise limitation.

Anxiety, Depression, and Health-Related QOL in Patients Diagnosed with PAH or CTEPH

BACKGROUND

Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are life-threatening diseases with a high burden of symptoms. Although depression, anxiety, and reduced health related quality of life (HRQOL) have also been reported, a comparative analysis which explores these traits and their underlying factors was lacking.

METHODS

A retrospective analysis of depression, anxiety, and health related QOL was conducted using a Hospital anxiety and depression scale (HADS) as well as the SF-36 HRQOL questionnaire. Results from these tools were compared with haemodynamic and functional parameters in 70 PAH and 23 CTEPH outpatients from a German tertiary care center specializing in pulmonary hypertension.

RESULTS

Although HRQOL was reduced in both cohorts of patients, individuals diagnosed with CTEPH scored lower in nearly all SF-36 parameters. Significance was noted in both "mental health" (p = 0.01) and "mental component summary score" (MCS) (p = 0.02). Depression was also more frequent in patients with CTEPH (56%) than in patients with PAH (30%), (p = 0.03). Overall, depression and anxiety correlated with most SF-36 scales in both PAH and CTEPH. In CTEPH, depression also correlated with the Borg Dyspnea Scale (r = 0.44, p = 0.01). These patients also had significantly lower pCO₂ levels than the PAH cohort reflecting more severe ventilation/perfusion mismatch. All other haemodynamic and functional parameters did not differ across the groups.

CONCLUSION

While both cohorts of patients suffer from a reduced HRQOL as well as depression and anxiety, decreases in mental health parameters are more pronounced in the CTEPH cohort. This suggests a strong effort to improve early detection, especially in dyspneic patients with classical risk factors for CTEPH and PAH and argues for mental illness interventions alongside routine clinical care provided to patients diagnosed with PAH or CTEPH.

Predicting cardiopulmonary involvement in patients with systemic sclerosis: complementary value of nailfold videocapillaroscopy patterns and disease-specific autoantibodies

Objective

To evaluate the prevalence of anti-extractable nuclear antigen (anti-ENA) antibodies in Dutch SSc patients and the predictive power of the combination of specific anti-ENA antibodies and nailfold videocapillaroscopy (NVC) patterns to improve identification of patients with high risk for cardiopulmonary involvement.

Methods

A total of 287 patients (79%) from the Leiden SSc-Cohort had data available on NVC-pattern (no SSc-specific, early, active, late) and anti-ENA antibodies. Associations between anti-ENA/NVC combinations with cardiopulmonary parameters were explored using logistic regression.

Results

Prevalence of ACA was 37%, anti-Scl-70 24%, anti-RNP 9%, anti-RNAPIII 5%, anti-fibrillarin 4%, anti-Pm/Scl 3%, anti-Th/To 0.3% and anti-Ku 1.4%. NVC showed a SSc-specific pattern in 88%: 10% early, 42% active and 36% late. The prevalence of different NVC patterns was equally distributed among specific anti-ENA antibodies, except for the absence of early pattern in anti-RNP positive patients. Fifty-one percent had interstitial lung disease (ILD), 59% had decreased diffusion capacity for carbon monoxide and 16% systolic pulmonary artery pressure >35 mmHg (sPAP↑). Regardless of ENA-subtype, NVC-pattern showed a stable association with presence of ILD or sPAP↑. For ILD, the odds ratios (ORs) were 1.3-1.4 ( P < 0.05 for analyses with anti-RNAPIII, anti-RNP). For diffusion capacity for carbon monoxide, the OR was 1.5 ( P < 0.05 for analyses with ACA, anti-Scl-70, anti-RNAPIII, anti-RNP). For sPAP↑, the ORs were 2.2-2.4 ( P < 0.05 for analyses with anti-RNAPIII, anti-RNP).

Conclusion

In Dutch SSc patients, all SSc-specific auto-antibodies were found, with ACA and anti-Scl-70 being the most prevalent. Strikingly, the association between NVC-pattern and heart/lung involvement was independent of specific anti-ENA antibodies, which might indicate microangiopathy is an important cause of organ involvement.

Effects of exercise training on pulmonary hemodynamics, functional capacity and inflammation in pulmonary hypertension

Pulmonary hypertension (PH) is characterized by severe exercise limitation mainly attributed to the impairment of right ventricular function resulting from a concomitant elevation of pulmonary vascular resistance and pressure. The unquestioned cornerstone in the management of patients with pulmonary arterial hypertension (PAH) is specific vasoactive medical therapy to improve pulmonary hemodynamics and strengthen right ventricular function. Nevertheless, evidence for a beneficial effect of exercise training (ET) on pulmonary hemodynamics and functional capacity in patients with PH has been growing during the past decade. Beneficial effects of ET on regulating factors, inflammation, and metabolism have also been described. Small case-control studies and randomized clinical trials in larger populations of patients with PH demonstrated substantial improvements in functional capacity after ET. These findings were accompanied by several studies that suggested an effect of ET on inflammation, although a direct link between this effect and the therapeutic benefit of ET in PH has not yet been demonstrated. On this background, the aim of the present review is to describe current concepts regarding the effects of exercise on the pulmonary circulation and pathophysiological limitations, as well as the clinical and mechanistic effects of exercise in patients with PH.

Cardiopulmonary exercise testing for detecting pulmonary arterial hypertension in systemic sclerosis

OBJECTIVES

Pulmonary arterial hypertension (PAH) is a devastating disease with limited survival and occurs as a frequent complication in patients with systemic sclerosis (SSc). A definite diagnosis of PAH is obtained by right heart catheterisation (RHC); however, the initial suspicion is raised by non-invasive methods. We assessed the diagnostic accuracy of key parameters derived from cardiopulmonary exercise testing (CPET) for detecting and ruling out SSc-associated PAH.

METHODS

In a multicentre setting, we prospectively evaluated 173 consecutive patients with SSc without known PAH, but with clinical suspicion of PAH. Each patient underwent CPET and RHC.

RESULTS

RHC identified PAH in 48 patients (27.8%), postcapillary pulmonary hypertension (PH) in 10 patients (5.8%) and ruled out PH in 115 patients (66.5%). CPET parameters correlated significantly with pulmonary haemodynamics. PeakVO₂ and VE/VCO₂ showed highest correlations with pulmonary arterial pressure, transpulmonary pressure gradient and pulmonary vascular resistance. Several parameters showed high sensitivity and specificity for PAH detection by receiver operating characteristic analysis. However, peakVO₂ showed highest diagnostic accuracy (sensitivity 87.5%, specificity 74.8% at a threshold level of 13.8 mL/min/kg). A peakVO₂ of >18.7 mL/kg/min was reached by 38/173 patients (22%) and excluded PAH in our cohort (negative predictive value 1.0). A nadir VE/VCO₂ ratio of >45.5 showed a positive predictive value of 1.0. Diagnostic accuracy was highest in patients with low pulmonary arterial wedge pressure (<12 mm Hg). There were no study-related serious adverse events.

CONCLUSIONS

CPET is a safe and valuable method in the non-invasive detection of SSc-associated PAH. It may be particularly beneficial for reducing unnecessary RHC procedures.

Cardiopulmonary exercise testing improves diagnostic specificity in patients with echocardiography-suspected pulmonary hypertension

BACKGROUND

Doppler echocardiography is usually the first diagnostic investigation for patients suspected with pulmonary hypertension (PH), but it is often inaccurate when used alone, especially in mild PH.

HYPOTHESIS

Cardiopulmonary exercise testing (CPET) may serve as a complementary tool to improve diagnostic accuracy in echocardiography-suspected "PH possible" patients.

METHODS

Eighty-eight consecutive patients with suspected PH (referred to as "PH possible" hereafter) based on echocardiography were included in the study. CPET was assessed subsequently and PH was confirmed by right-heart catheterization in all subjects. We analyzed CPET data from patients and derived a CPET prediction rule to hemodynamically differentiate PH.

RESULTS

Eighty-eight patients (27 patients with confirmed PH, and PH ruled out in 61 patients) were included in the study. Compared with non-PH patients, the PH subjects had lower peak oxygen uptake (VO₂ ), aerobic capacity (AT), peak partial pressure of end-tidal CO₂ (P_ET CO₂ ), oxygen uptake efficiency plateau (OUEP), and oxygen uptake efficiency slope (OUES), along with higher minute ventilation (VE)/carbon dioxide output (VCO₂ ) slope and lowest VE/VCO₂ (P < 0.001). VE/VCO₂ slope and AT were independent predictors of PH derived from multivariate logistic regression adjusted for age and body mass index. A score combining VE/VCO₂ slope and AT reached a high area under the curve value of 0.98. A score ≥0.5 had 95% specificity and 92.6% sensitivity for diagnosis of PH.

CONCLUSIONS

A score combining VE/VCO₂ slope and AT provides high specificity in screening out PH from a pool of echocardiography-suspected PH patients.

Comparison of change in end tidal carbon dioxide after three minutes of step exercise between systemic sclerosis patients with and without pulmonary hypertension

OBJECTIVES

Pulmonary hypertension (PH) is an important cause of morbidity and mortality in patients with SSc. The submaximal heart and pulmonary evaluation (step test) is a non-invasive, submaximal stress test that could be used to identify SSc patients with PH. Our aims were to determine whether change in end tidal carbon dioxide ([Formula: see text]) from rest to end-exercise, and the minute ventilation to carbon dioxide production ratio ([Formula: see text]), both as measured by the step test, differ between SSc patients with and without PH. We also examined differences in validated self-report questionnaires and potential PH biomarkers between SSc patients with and without PH.

METHODS

We performed a cross-sectional study of 27 patients with limited or dcSSc who underwent a right heart catheterization within 24 months prior to study entry. The study visit consisted of questionnaire completion; history; physical examination; step test performance; and phlebotomy. [Formula: see text], [Formula: see text], self-report data and biomarkers were compared between patients with and without PH.

RESULTS

SSc patients with PH had a statistically significantly lower median (interquartile range) [Formula: see text] than SSc patients without PH [-2.1 (-5.1 to 0.7) vs 1.2 (-0.7 to 5.4) mmHg, P = 0.035], and a statistically significantly higher median (interquartile range) [Formula: see text] [53.4 (39-64.1) vs 36.4 (31.9-41.1), P = 0.035]. There were no statistically significant differences in self-report data or biomarkers between groups.

CONCLUSION

[Formula: see text] and [Formula: see text] as measured by the step test are statistically significantly different between SSc patients with and without PH. [Formula: see text] and [Formula: see text] may be useful screening tools for PH in the SSc population.

Exercise intolerance in pulmonary hypertension: mechanism, evaluation and clinical implications

INTRODUCTION

Exercise intolerance in pulmonary hypertension (PH) is a major factor affecting activities of daily living and quality of life. Evaluation strategies (i.e., non-invasive and invasive tests) are integral to providing a comprehensive assessment of clinical and functional status. Despite a growing body of literature on the clinical consequences of PH, there are limited studies discussing the contribution of various physiological systems to exercise intolerance in this patient population.

AREAS COVERED

This review, through a search of various databases, describes the physiological basis for exercise intolerance across the various PH etiologies, highlights the various exercise evaluation methods and discusses the rationale for exercise training amongst those diagnosed with PH. Expert commentary: With the growing importance of evaluating exercise capacity in PH (class 1, Level C recommendation), understanding why exercise performance is altered in PH is crucial. Thus, the further study is required for better quality evidence in this area.

Physiological Techniques and Pulmonary Hypertension - Left Heart Disease

Group 2 Pulmonary hypertension (PH) is associated with left heart disease (LHD;Group 2 PH) and is the most common form of PH. Group 2 PH represents an important subgroup of patients with LHD where the development of PH leads to a significant increase in morbidity and mortality. Early diagnosis may provide an opportunity to intervene and significantly delay progression. In addition to clinical suspicion, several approaches including hemodynamic assessment, exercise testing, and imaging techniques play an important role in better disease characterization and management. Here, we review the role of physiologic based hemodynamic and exercise assessments of Group 2 PH patients.

Cardiopulmonary Exercise Testing as a Tool for Diagnosing Pulmonary Hypertension in Patients with Dilated Cardiomyopathy

Background

Recently, it has become increasingly recognized that pulmonary hypertension (PH) is a particularly threatening result of left‐sided heart disease. However, there have been few investigations of the impact of cardiopulmonary exercise testing (CPX) variables on PH in dilated cardiomyopathy (DCM). We evaluated the usefulness of crucial CPX variables for detecting elevated pulmonary arterial pressure (PAP) in patients with DCM.

Methods

Ninety subjects with DCM underwent cardiac catheterization and CPX at our hospital. Receiver operator characteristic (ROC) analysis was performed to assess the ability of CPX variables to distinguish between the presence and absence of PH.

Results

Overall mean values were: mean PAP (mPAP), 18.0 ± 9.6 mmHg; plasma brain natriuretic peptide, 233 ± 295 pg/mL; and left ventricular ejection fraction, 30.2 ± 11.0%. Patients were allocated to one of two groups on the basis of mean PAP, namely DCM without PH [mean PAP (mPAP) <25 mmHg; n = 75] and DCM with PH (mPAP ≥25 mmHg; n = 15). A cutoff achieved percentage of predicted peak VO₂ (%PPeak VO₂) of 52.5% was the best predictor of an mPAP ≥25 mmHg in the ROC analysis (area under curve: 0.911). In the multivariate analysis, %PPeak VO₂ was the only significant independent predictor of PH (Wald 6.52, odds ratio 0.892, 95% CI 0.818–0.974; P = 0.011).

Conclusions

%PPeak VO₂ was strongly associated with the presence of PH in patients with DCM. Taken together, these findings indicate that CPX variables could be important for diagnosing PH in patients with DCM.

Risk factors for severity and manifestations in systemic sclerosis and prediction of disease course

Systemic sclerosis (SSc, or scleroderma) is a rheumatic disease with distinct features that encompass autoimmunity, vascular lesions (vasculopathy) and tissue fibrosis. The disease has a high morbidity and mortality compared with other rheumatic diseases. This review discusses risk factors and markers that predict the disease course and the occurrence of disease manifestations, with an emphasis on major organ involvement. In addition, risk factors will be described that are associated with mortality in SSc patients. The review addresses the impact of recent developments on screening, diagnosis and risk stratification as well as the need for further research where data are lacking.

A prediction model for progressive disease in systemic sclerosis

Objective

To develop a model that assesses the risk for progressive disease in patients with systemic sclerosis (SSc) over the short term, in order to guide clinical management.

Methods

Baseline characteristics and 1 year follow-up results of 163 patients with SSc referred to a multidisciplinary healthcare programme were evaluated. Progressive disease was defined as: death, ≥10% decrease in forced vital capacity, ≥15% decrease in diffusing capacity for carbon monoxide, ≥10% decrease in body weight, ≥30% decrease in estimated-glomerular filtration rate, ≥30% increase in modified Rodnan Skin Score (with Δ≥5) or ≥0.25 increase in Scleroderma Health Assessment Questionnaire. The number of patients with progressive disease was determined. Univariable and multivariable logistic regression analyses were used to assess the probability of progressive disease for each individual patient. Performance of the prediction model was evaluated using a calibration plot and area under the receiver operating characteristic curve.

Results

63 patients had progressive disease, including 8 patients who died ≤18 months after first evaluation. Multivariable analysis showed that friction rubs, proximal muscular weakness and decreased maximum oxygen uptake as % predicted, adjusted for age, gender and use of immunosuppressive therapy at baseline, were significantly associated with progressive disease. Using the prediction model, the predicted chance for progressive disease increased from a pretest chance of 37% to 67–89%.

Conclusions

Using the prediction model, the chance for progressive disease for individual patients could be doubled. Friction rubs, proximal muscular weakness and maximum oxygen uptake as % predicted were identified as relevant parameters.

CO2 pulse and acid-base status during increasing work rate exercise in health and disease

The CO2 pulse (VCO2/heart rate), analogous to the O2 pulse (VO2/heart rate), was calculated during cardiopulmonary exercise testing and evaluated in normal and diseased states. Our aim was to define its application in its release in excess of that from VCO2/heart rate in the presence of impaired cardiovascular and lung function. In the current study, forty-five patients were divided into six physiological states: normal, exercise-induced myocardial ischemia, chronic heart failure, pulmonary vasculopathy, chronic obstructive pulmonary disease, and interstitial lung disease. We subtracted the O2 pulse from the CO2 pulse to determine the exhaled CO2 that could be attributed to CO2 pulse of buffering of lactic acid. The difference between the CO2 pulse and O2 pulse (VCO2/heart rate-VO2/heart rate) includes CO2 generated from HCO3(-) buffering of lactic acid. The accumulated CO2 per body mass was found to be significantly correlated with the corresponding [HCO3(-)] decrease (R(2)=0.72; P<0.0001). In summary, the increase in CO2 pulse over the O2 pulse accounted for the anaerobically-generated excess-CO2 in each of the physiological states and correlated with the decreases in the arterial Bicarbonate concentration.

Connective tissue disease-associated pulmonary arterial hypertension

Although rare in its idiopathic form, pulmonary arterial hypertension (PAH) is not uncommon in association with various associated medical conditions, most notably connective tissue disease (CTD). In particular, it develops in approximately 10% of patients with systemic sclerosis and so these patients are increasingly screened to enable early detection. The response of patients with systemic sclerosis to PAH-specific therapy appears to be worse than in other forms of PAH. Survival in systemic sclerosis-associated PAH is inferior to that observed in idiopathic PAH. Potential reasons for this include differences in age, the nature of the underlying pulmonary vasculopathy and the ability of the right ventricle to cope with increased afterload between patients with systemic sclerosis-associated PAH and idiopathic PAH, while coexisting cardiac and pulmonary disease is common in systemic sclerosis-associated PAH. Other forms of connective tissue-associated PAH have been less well studied, however PAH associated with systemic lupus erythematosus (SLE) has a better prognosis than systemic sclerosis-associated PAH and likely responds to immunosuppression.

Cardiopulmonary exercise testing to detect chronic thromboembolic pulmonary hypertension in patients with normal echocardiography

BACKGROUND

Chronic thromboembolic pulmonary hypertension (CTEPH) is a serious complication of pulmonary embolism (PE). Taking into account the reported incidence of CTEPH after acute PE, the number of patients with undiagnosed CTEPH may be high.

OBJECTIVES

We aimed to determine if cardiopulmonary exercise testing (CPET) could serve as complementary tool in the diagnosis of CTEPH and can detect CTEPH in patients with normal echocardiography.

METHODS

At diagnosis, we analyzed the data of CPET parameters in 42 patients with proven CTEPH and 51 controls, and evaluated the performance of two scores.

RESULTS

VE/VCO2 slope, EQO2, EQCO2, P(A-a)O2, end-tidal partial pressure of CO2 at anaerobic threshold (PETCO2) and capillary to end-tidal carbon dioxide gradient [P(c-ET)CO2] were significantly different between patients with CTEPH and controls (p < 0.001). P(c-ET)CO2 was the single parameter with the highest sensitivity (85.7%) and specificity (88.2%). A score combining VE/VCO2 slope, P(A-a)O2, P(c-ET)CO2, PETCO2 [4-parameter-CPET (4-P-CPET) score] reached a sensitivity of 83.3% and a specificity of 92.2% after cross-validation. In 42 patients with CTEPH, echocardiography identified PH in 29 patients (69%), but it was normal in 13 patients (31%). All patients with normal or unmeasurable right ventricular systolic pressure had a pathological CPET. Twelve of the 13 patients (92%) were detected by both CPET scores.

CONCLUSION

CPET is a useful noninvasive diagnostic tool for the detection of CTEPH in patients with suspected PH but normal echocardiography. The 4-P-CPET score provides a high sensitivity with the highest specificity.

Impact of pulmonary hypertension on exercise performance in patients with interstitial lung disease undergoing evaluation for lung transplantation

BACKGROUND AND OBJECTIVE

Pulmonary hypertension (PH) is a known complication in patients with interstitial lung disease (ILD). Cardiopulmonary exercise testing (CPET) is an essential tool for the assessment of patients with cardiac and pulmonary diseases due to its prognostic and therapeutic implications. Few studies have evaluated the relationship between CPET response and mean pulmonary artery pressures (mPAP) in ILD. The purpose of the present study was to determine and compare the potential correlations between CPET, 6-min walk test (6MWT), pulmonary function testing (PFT) and PH in patients with ILD being evaluated for lung transplantation.

METHODS

The present study reviewed patients with ILD who received lung transplantations and had CPETs within 2 years before transplantation, right heart catheterizations, PFTs and 6MWTs within 4 months of CPET.

RESULTS

A total of 72 patients with ILD were analysed; 36% had PH. There were significant correlations between mPAP and CPET parameters in patients with PH; but mPAP had no impact on percent of predicted diffusion capacity of the lung for carbon monoxide or 6-min walk distance (6MWD). CPET parameters were able to detect differences between levels of severity of PH through the use of the ratio of minute ventilation to rate of carbon dioxide production (VE/VCO2) and the partial pressure of end-tidal carbon dioxide.

CONCLUSIONS

This is the first study that analyses 6MWD, PFT and CPET in patients with ILD awaiting lung transplantation with and without PH. The present study demonstrates the significant impact of PH on exercise capacity and performance in patients with ILD awaiting lung transplantation.

Submaximal heart and pulmonary evaluation: a novel noninvasive test to identify pulmonary hypertension in patients with systemic sclerosis

OBJECTIVE

Pulmonary hypertension (PH) is a leading cause of death in patients with systemic sclerosis (SSc; scleroderma). Although right-sided heart catheterization (RHC) is the gold standard for diagnosing PH, it is an invasive test with associated risks. The submaximal heart and pulmonary evaluation (step test) is a noninvasive, submaximal stress test that could be used to identify patients with PH. The purpose of this study is to assess the correlation between change in end tidal carbon dioxide (ΔPETCO2 ) from rest to end-exercise on the step test and mean pulmonary artery pressure (mPAP) on RHC in SSc patients.

METHODS

This is a retrospective cohort study of patients with limited or diffuse cutaneous SSc who were evaluated in an academic cardiology practice between November 2007 and November 2011 and underwent a step test and RHC. Statistical analysis was performed using Spearman's correlation test and multivariable linear regression.

RESULTS

A total of 679 charts were reviewed. Nineteen SSc patients who underwent a step test and RHC were included. ΔPETCO2 was negatively correlated with mPAP (r = -0.82, P < 0.0001). In a multivariable linear regression model evaluating the relationship between ΔPETCO2 and mPAP, controlling for age, sex, and time between and order of step test and RHC, ΔPETCO2 remained the only variable statistically significantly associated with mPAP (P < 0.001). The step test had a sensitivity of 100%, specificity of 75%, positive predictive value of 93.8%, and negative predictive value of 100% for the diagnosis of PH.

CONCLUSION

ΔPETCO2 on the step test has a strong, statistically significant negative correlation with mPAP on RHC.