Cardiopulmonary Exercise Testing in Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension: the diagnostic assessment

Chronic Thromboembolic Pulmonary Hypertension (CTEPH) presents a significant diagnostic challenge due to its complex and often nonspecific clinical manifestations. This review outlines a comprehensive approach to the diagnostic assessment of CTEPH, emphasizing the importance of a high index of suspicion in patients with unexplained dyspnea or persistent symptoms post-acute pulmonary embolism. We discuss the pivotal role of multimodal imaging, including echocardiography, ventilation/perfusion scans, CT pulmonary angiography, and magnetic resonance imaging, in the identification and confirmation of CTEPH. Furthermore, the review highlights the essential function of right heart catheterization in validating the hemodynamic parameters indicative of CTEPH, establishing its definitive diagnosis. Advances in diagnostic technologies and the integration of a multidisciplinary approach are critical for the timely and accurate diagnosis of CTEPH, facilitating early therapeutic intervention and improving patient outcomes. This manuscript aims to equip clinicians with the knowledge and tools necessary for the efficient diagnostic workflow of CTEPH, promoting awareness and understanding of this potentially treatable cause of pulmonary hypertension.

Cardiopulmonary exercise testing in clinical practice: Principles, applications, and basic interpretation

Cardiopulmonary exercise testing (CPET) provides a noninvasive and integrated assessment of the response of the respiratory, cardiovascular, and musculoskeletal systems to exercise. This information improves the diagnosis, risk stratification, and therapeutic management of several clinical conditions. Additionally, CPET is the gold standard test for cardiorespiratory fitness quantification and exercise prescription, both in patients with cardiopulmonary disease undergoing cardiac or pulmonary rehabilitation programs and in healthy individuals, such as high-level athletes. In this setting, the relevance of practical knowledge about this exam is useful and of interest to several medical specialties other than cardiology. However, despite its multiple established advantages, CPET remains underused. This article aims to increase awareness of the value of CPET in clinical practice and to inform clinicians about its main indications, applications, and basic interpretation.

Cardiopulmonary exercise testing in transthyretin amyloid cardiomyopathy patients: a long-term follow-up study

AIMS

Patients with transthyretin amyloid cardiomyopathy (ATTR-CM) experience reduced functional capacity. We evaluated changes in functional capacity over extensive follow-up using cardiopulmonary exercise testing (CPX).

METHODS

ATTR-CM patients underwent CPX and blood testing at baseline, first [V1, 8 (6-10) months] and second follow-up (V2) at 35 (26-41) months after start of disease-specific therapy.

RESULTS

We included 34 ATTR-CM patients, aged 77 (±6) years (88.2% men). CPX showed two patterns with functional capacity improvement at V1 and deterioration at V2. Peak work capacity ( P = 0.005) and peak oxygen consumption (VO 2 , P = 0.012) increased at V1 compared with baseline and decreased at V2. The ventilation to carbon dioxide relationship slope (VE/VCO 2 ) increased at V2 compared with baseline and V1 ( P = 0.044). A cut-off for peak VO 2 at 14 ml/kg·min showed more events (composite of death and heart failure hospitalization): less than 14 vs. greater than 14 ml/kg·min ( P  = 0.013). Cut-offs for VE/VCO 2 slope at 40 showed more events greater than 40 vs. less than 40 ( P  = 0.009).

CONCLUSION

ATTR-CM patients showed an improvement and deterioration in the short-term and long-term follow-up, respectively, with a better prognosis for those with peak VO 2 above 14 ml/kg·min and for a VE/VCO 2 slope below 40.

Cardiopulmonary Exercise Testing in Children With Long COVID: A Case-controlled Study

BACKGROUND

Cardiopulmonary exercise testing (CPET) is a noninvasive and nonexpensive diagnostic tool, that provides a comprehensive evaluation of the pulmonary, cardiovascular, and skeletal muscle systems' integrated reactions to exercise. CPET has been extensively used in adults with Long COVID (LC), while the evidence about its role in children with this condition is scarce.

METHODS

Prospective, case-controlled observational study. Children with LC and a control group of healthy children underwent CPET. CPET findings were compared within the 2 groups, and within the LC groups according to main clusters of persisting symptoms.

RESULTS

Sixty-one children with LC and 29 healthy controls were included. Overall, 90.2% of LC patients (55 of 61) had a pathologic test vs 10.3% (3/29) of the healthy control. Children with LC presented a statistically significant higher probability of having abnormal values of peak VO2 ( P = 0.001), AT% pred ( P <0.001), VO2/HR % ( P = 0.03), VO2 work slope ( P = 0.002), VE/VCO2 slope ( P = 0.01). The mean VO2 peak was 30.17 (±6.85) in LC and 34.37 (±6.55) in healthy patients ( P = 0.007).

CONCLUSIONS

Compared with healthy controls, children with LC have objective impaired functional capacity (expressed by a low VO2 peak), signs of deconditioning and cardiogenic inefficiency when assessed with CPET. As such, CPET should be routinely used in clinical practice to objectify and phenotype the functional limitations of children with LC, and to follow-up them.

Persisting exercise ventilatory inefficiency in subjects recovering from COVID-19. Longitudinal data analysis 34 months post-discharge

BACKGROUND

SARS-CoV-2 infection has raised concerns about long-term health repercussions. Exercise ventilatory inefficiency (EVin) has emerged as a notable long-term sequela, potentially impacting respiratory and cardiovascular health. This study aims to assess the long-term presence of EVin after 34 months and its association with cardiorespiratory health in post-COVID patients.

METHODS

In a longitudinal study on 32 selected post-COVID subjects, we performed two cardiopulmonary exercise tests (CPETs) at 6 months (T0) and 34 months (T1) after hospital discharge. The study sought to explore the long-term persistence of EVin and its correlation with respiratory and cardiovascular responses during exercise. Measurements included also V̇O2peak, end-tidal pressure of CO2 (PETCO2) levels, oxygen uptake efficiency slope (OUES) and other cardiorespiratory parameters, with statistical significance set at p < 0.05. The presence of EVin at both T0 and T1 defines a persisting EVin (pEVin).

RESULTS

Out of the cohort, five subjects (16%) have pEVin at 34 months. Subjects with pEVin, compared to those with ventilatory efficiency (Evef) have lower values of PETCO2 throughout exercise, showing hyperventilation. Evef subjects demonstrated selective improvements in DLCO and oxygen pulse, suggesting a recovery in cardiorespiratory function over time. In contrast, those with pEvin did not exhibit these improvements. Notably, significant correlations were found between hyperventilation (measured by PETCO2), oxygen pulse and OUES, indicating the potential prognostic value of OUES and Evin in post-COVID follow-ups.

CONCLUSIONS

The study highlights the clinical importance of long-term follow-up for post-COVID patients, as a significant group exhibit persistent EVin, which correlates with altered and potentially unfavorable cardiovascular responses to exercise. These findings advocate for the continued investigation into the long-term health impacts of COVID-19, especially regarding persistent ventilatory inefficiencies and their implications on patient health outcomes.

Exercise Testing in Patients with Pulmonary Hypertension

Pulmonary hypertension (PH), defined by a mean pulmonary artery pressure of >20 mm Hg, often presents with non-specific symptoms such as dyspnea and exercise intolerance, making it difficult to diagnose early before the onset of right heart dysfunction. Therefore, exercise testing can be of great utility for clinicians who are evaluating patients with an unclear etiology of exercise intolerance by helping identify the underlying mechanisms of their disease. The presence of PH is associated with adverse clinical outcomes, with distinct differences and patterns in the cardiovascular and ventilatory responses to exercise across various PH phenotypes. We discuss the role of exercise-invasive hemodynamic testing, cardiopulmonary exercise testing, and exercise stress echocardiography modalities across the spectrum of PH.

Systemic Arterial Oxygen Levels Differentiate Pre- and Post-capillary Predominant Hemodynamic Abnormalities During Exercise in Undifferentiated Dyspnea on Exertion

BACKGROUND

Whether systemic oxygen levels (SaO2) during exercise can provide a window into invasively derived exercise hemodynamic profiles in patients with undifferentiated dyspnea on exertion is unknown.

METHODS

We performed cardiopulmonary exercise testing with invasive hemodynamic monitoring and arterial blood gas sampling in individuals referred for dyspnea on exertion. Receiver operator analysis was performed to distinguish heart failure with preserved ejection fraction from pulmonary arterial hypertension.

RESULTS

Among 253 patients (mean ± SD, age 63 ± 14 years, 55% female, arterial O2 [PaO2] 87 ± 14 mmHg, SaO2 96% ± 4%, resting pulmonary capillary wedge pressure [PCWP] 18 ± 4mmHg, and pulmonary vascular resistance [PVR] 2.7 ± 1.2 Wood units), there was no exercise PCWP threshold, measured up to 49 mmHg, above which hypoxemia was consistently observed. Exercise PaO2 was not correlated with exercise PCWP (rho = 0.04; P = 0.51) but did relate to exercise PVR (rho = -0.46; P < 0.001). Exercise PaO2 and SaO2 levels distinguished left-heart-predominant dysfunction from pulmonary-vascular-predominant dysfunction with an area under the curve of 0.89 and 0.89, respectively.

CONCLUSION

Systemic O2 levels during exercise distinguish relative pre- and post-capillary pulmonary hemodynamic abnormalities in patients with undifferentiated dyspnea. Hypoxemia during upright exercise should not be attributed to isolated elevation in left heart filling pressures and should prompt consideration of pulmonary vascular dysfunction.

Dysregulation of ventilation at day and night time in heart failure

Heart failure (HF) is characterized by an increase in ventilatory response to exercise of multifactorial aetiology and by a dysregulation in the ventilatory control during sleep with the occurrence of both central and obstructive apnoeas. In this setting, the study of the ventilatory behaviour during exercise, by cardiopulmonary exercise testing, or during sleep, by complete polysomnography or simplified nocturnal cardiorespiratory monitoring, is of paramount importance because of its prognostic value and of the possible effects of sleep-disordered breathing on the progression of the disease. Moreover, several therapeutic interventions can significantly influence ventilatory control in HF. Also, rest daytime monitoring of cardiac, metabolic, and respiratory activities through specific wearable devices could provide useful information for HF management. The aim of the review is to summarize the main studies conducted at Centro Cardiologico Monzino on these topics.

Tricuspid Valve Regurgitation: Current Understanding and Novel Treatment Options

Managing patients with severe symptomatic tricuspid regurgitation (TR) remains extremely challenging, with a lack of consensus on when and how to treat it. Tricuspid valve pathology has been disregarded for a very long time because of the established belief that treating left-sided heart diseases would lead to the resolution or significant improvement of TR. Initially considered benign, severe TR has been found to be a strong predictor of prognosis. Despite the increasing prevalence and the disabling nature of this disease, the great majority of patients with clinically significant TR have seldom been considered for structural interventions. Numerous surgical and transcatheter treatment options are now available; however, optimal timing and procedural selection remain crucial aspects influencing outcomes. According to recent evidence in the literature, early referral is associated with good short and long-term outcomes, and various predictors of favorable outcomes following either surgical or transcatheter treatment have been identified. Evaluation by a multidisciplinary heart team with expertise in tricuspid valve disease is of paramount importance to identify adequate treatment for every patient.

The Current Role of Cardiopulmonary Exercise Test in the Diagnosis and Management of Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is a progressive disease with a poor prognosis if left untreated. Despite remarkable achievements in understanding disease pathophysiology, specific treatments, and therapeutic strategies, we are still far from a definitive cure for the disease, and numerous evidences have underlined the importance of early diagnosis and treatment to improve the prognosis. Cardiopulmonary exercise testing (CPET) is the gold standard for assessing functional capacity and evaluating the pathophysiological mechanisms underlying exercise limitation. As effort dyspnea is the earliest and one of the main clinical manifestations of PAH, CPET has been shown to provide valid support in early detection, differential diagnosis, and prognostic stratification of PAH patients, being a useful tool in both the first approach to patients and follow-up. The purpose of this review is to present the current applications of CPET in pulmonary hypertension and to propose possible future utilization to be further investigated.

Chronic thromboembolic pulmonary hypertension and the post-pulmonary embolism (PE) syndrome

Over a third of patients surviving acute pulmonary embolism (PE) will experience long-term cardiopulmonary limitations. Persistent thrombi, impaired gas exchange, and altered hemodynamics account for aspects of the postpulmonary embolism syndrome that spans mild functional limitations to debilitating chronic thromboembolic pulmonary hypertension (CTEPH), the most worrisome long-term consequence. Though pulmonary endarterectomy is potentially curative for the latter, less is understood surrounding chronic thromboembolic disease (CTED) and post-PE dyspnea. Advances in pulmonary vasodilator therapies and growing expertise in balloon pulmonary angioplasty provide options for a large group of patients ineligible for surgery, or those with persistent postoperative pulmonary hypertension. In this clinical review, we discuss epidemiology and pathophysiology as well as advances in diagnostics and therapeutics surrounding the spectrum of disease that may follow months after acute PE.

Evaluation and Management of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a treatable form of pulmonary hypertension and right heart failure. CTEPH (group 4 pulmonary hypertension) is caused by persistent organized thromboembolic obstruction of the pulmonary arteries from incompletely resolved acute pulmonary embolism. CTEPH also may present without prior VTE history, which can contribute to its underrecognition. The true incidence of CTEPH is unclear, but is estimated to be approximately 3% after acute pulmonary embolism. V˙/Q˙ scintigraphy is the best screening test for CTEPH, with CT scan imaging and other advanced imaging methods now playing a larger role in disease detection and confirmation. Perfusion defects on V˙/Q˙ scintigraphy in the setting of pulmonary hypertension are suggestive of CTEPH, but pulmonary angiography and right heart catheterization are required for confirmation and treatment planning. CTEPH potentially is curative with pulmonary thromboendarterectomy surgery, with mortality rates of approximately 2% at expert centers. Advances in operative techniques are allowing more distal endarterectomies to be performed successfully with favorable outcomes. However, more than one-third of patients may be considered inoperable. Although these patients previously had minimal therapeutic options, effective treatments now are available with pharmacotherapy and balloon pulmonary angioplasty. Diagnosis of CTEPH should be considered in all patients with suspicion of pulmonary hypertension. Treatments for CTEPH have advanced with improvements in outcomes for both operable and inoperable patients. Therapy should be tailored based on multidisciplinary team evaluation to ensure optimal treatment response.

Cardiopulmonary Exercise Testing, Rehabilitation, and Exercise Training in Postpulmonary Embolism

Long-term exercise intolerance and functional limitations are common after an episode of acute pulmonary embolism (PE), despite 3 to 6 months of anticoagulation. These persistent symptoms are reported in more than half of the patients with acute PE and are referred as "post-PE syndrome." Although these functional limitations can occur from persistent pulmonary vascular occlusion or pulmonary vascular remodeling, significant deconditioning can be a major contributing factor. Herein, the authors review the role of exercise testing to elucidate the mechanisms of exercise limitations to guide next steps in management and exercise training for musculoskeletal deconditioning.

Risk Stratification in Pulmonary Arterial Hypertension, Update and Perspectives

Risk stratification in pulmonary arterial hypertension (PAH) is crucial in assessing patient prognosis. It serves a prominent role in everyday patient care and can be determined using several validated risk assessment scores worldwide. The recently published 2022 European Society of Cardiology (ESC)/European Respiratory Society (ERS) guidelines underline the importance of risk stratification not only at baseline but also during follow-up. Achieving a low-risk status has now become the therapeutic goal, emphasising the importance of personalised therapy. The application of these guidelines is also important in determining the timing for lung transplantation referral. In this review, we summarise the most relevant prognostic factors of PAH as well as the parameters used in PAH risk scores and their evolution in the guidelines over the last decade. Finally, we describe the central role that risk stratification plays in the current guidelines not only in European countries but also in Asian countries.

Role of cardiopulmonary exercise test in early diagnosis of pulmonary hypertension in scleroderma patients

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a severe, high mortality and progressive disease. Early diagnosis and treatment improves the prognosis. Patients with scleroderma disease presents high risk of developing PAH. Established screening strategies - echocardiogram and DETECT algorithm - recognize the disease when it is already advanced. Cardiopulmonary exercise testing (CPET) detects pulmonary vascular injury in earlier stages.

METHODS

Prospective study of 52 consecutive patients diagnosed of scleroderma in our health area, during 2 years (2018 and 2019). All of them undergo CPET, in addition to the annual systematic screening. Sensitivity of current PAH screening is compared to CPET. To confirm the presence of PAH, right heart catheterization (RHC) is performed. In case of suspected PAH in CPET, but non-confirmatory right heart catheterization at rest, patients carried out exercise RHC.

RESULTS

Fifty-two CPET were performed, of which 16 suggested PAH. Resting RHC confirmed PAH in 5 patients and exercise RHC in 7 (diagnostic sensitivity of CPET together with rest and exercise catheterization of 100%). Of these 16 patients, DETECT had identified 10, of whom resting RHC confirmed PAH in 3 and exercise RHC in 2 (guideline-based diagnostic algorithm sensitivity 70%).

CONCLUSIONS

CPET and exercise RHC could detect PAH earlier than established screening in patients with scleroderma disease, allowing early diagnosis.

Long-term exercise and pulmonary function outcomes in a contemporary cohort of children with congenital diaphragmatic hernia

OBJECTIVE

Congenital diaphragmatic hernia (CDH) survivors are at risk for long-term exercise impairment and pulmonary morbidity, but the generalizability of prior reported cohorts are limited by reduced disease severity and older surgical eras. We assessed the mid-childhood exercise and pulmonary function outcomes in a contemporary cohort of CDH survivors.

STUDY DESIGN

In this retrospective cohort study, we identified 36 consecutive pediatric CDH survivors who underwent cardiopulmonary exercise testing (CPET) and spirometry from 2014 to 2021. Inferential statistics compared survivors with age-, sex-, and size-matched healthy controls; univariate analyses identified factors associated with abnormal testing.

RESULTS

Maximal effort CPET and resting spirometry were completed by 27/36 (75%) and 31/36 (86%) subjects, respectively (median age: 8.1 years [interquartile range: 7.5, 10]; 16 females [44%]). Abnormal CPET (percent predicted [pp] peak VO₂  < 80%) was more common in the CDH cohort (12 vs. 1, p < 0.001) and associated with longer neonatal intensive care unit (NICU) stay (p = 0.02) and oxygen therapy at discharge (p = 0.03). Exercise impairment was mild (pp peak VO₂ 70%-80%), moderate (60%-70%), and severe (<60%) in 6, 4, and 2 survivors, respectively. Abnormal spirometry was more common in the CDH cohort (21 vs. 3, p < 0.001; obstructive [n = 15], restrictive [n = 6]) and associated with decreased gestational age (p = 0.046), longer mechanical ventilation in the NICU (p = 0.02), and orthopedic abnormalities (p = 0.03).

CONCLUSION(S)

Exercise capacity was normal or mildly impaired in most CDH survivors, however, approximately two-thirds demonstrated abnormal spirometry. Impaired exercise capacity and lung function were associated with severity of lung disease postnatally. These data support cardiopulmonary follow-up throughout childhood.

Incorporation of noninvasive assessments in risk prediction for pulmonary arterial hypertension

Risk assessment for pulmonary arterial hypertension (PAH) utilizing noninvasive prognostic variables could be more practical in real-world scenarios, especially at follow-up reevaluations. Patients who underwent comprehensive evaluations both at baseline and at follow-up visits were enrolled. The primary endpoint was all-cause mortality. Predictive variables identified by Cox analyses were further incorporated with the French noninvasive risk prediction approach. A total of 580 PAH patients were enrolled. During a median follow-up time of 47.0 months, 112 patients (19.3%) died. By multivariate Cox analyses, tricuspid annular plane systolic excursion (TAPSE), TAPSE/pulmonary arterial systolic pressure (PASP), and cardiopulmonary exercise testing-derived peak oxygen consumption (VO2) remained independent predictors for survival. Regarding the French noninvasive risk prediction method, substituting N-terminal pro-b-type natriuretic peptide (NT-proBNP) with the newly derived low-risk criteria of a TAPSE ≥ 17 mm or a TAPSE/PASP > 0.17 mm/mmHg, or alternating 6-min walking distance with a peak VO2 ≥ 44 %predicted retained the discrimination power. When recombining the low-risk criteria, the combination of World Health Organization functional class (WHO FC), TAPSE and peak VO2 at baseline, and the combination of WHO FC, NT-proBNP, and peak VO2 at follow-up showed better discriminative ability than the other combinations. In conclusion, Peak VO2, TAPSE, and TAPSE/PASP are significant prognostic predictors for survival in PAH, with incremental prognostic value when incorporated with the French noninvasive risk prediction approach, especially at reevaluations. For better risk prediction, WHO FC, at least one measurement of exercise capacity and one measurement of right ventricular function should be considered.

Emerging phenotypes of pulmonary hypertension associated with COPD: a field guide

PURPOSE OF REVIEW

Pulmonary hypertension (PH) is a common complication of chronic obstructive lung disease (COPD), but clinical presentation is variable and not always 'proportional' to the severity of the obstructive disease. This review aims to analyze heterogeneity in clinical features of PH-COPD, providing a guide for diagnosis and management according to phenotypes.

RECENT FINDINGS

Recent works have focused on severe PH in COPD, providing insights into the characteristics of patients with predominantly vascular disease. The recently recognized 'pulmonary vascular phenotype', characterized by severe PH and mild airflow obstruction with severe hypoxemia, has markedly worse prognosis and may be a candidate for large trials with pulmonary vasodilators. In severe PH, which might be best described by a pulmonary vascular resistance threshold, there may also be a need to distinguish patients with mild COPD (pulmonary vascular phenotype) from those with severe COPD ('Severe COPD-Severe PH' phenotype).

SUMMARY

Correct phenotyping is key to appropriate management of PH associated with COPD. The lack of evidence regarding the use of pulmonary vasodilators in PH-COPD may be due to the existence of previously unrecognized phenotypes with different responses to therapy. This review offers the clinician caring for patients with COPD and PH a phenotype-focused approach to diagnosis and management, aimed at personalized care.

Exercise Intolerance in Post-Acute Sequelae of COVID-19 and the Value of Cardiopulmonary Exercise Testing- a Mini-Review

Coronavirus disease (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with systemic organ damage in the most severe forms. Long-term complications of SARS-CoV-2 appear to be restricted to severe presentations of COVID-19, but many patients with persistent symptoms have never been hospitalized. Post-acute sequelae of COVID-19 (PASC) represents a heterogeneous group of symptoms characterized by cardiovascular, general, respiratory, and neuropsychiatric sequelae. The pace of evidence acquisition with PASC has been rapid, but the mechanisms behind it are complex and not yet fully understood. In particular, exercise intolerance shares some features with other classic respiratory and cardiac disorders. However, cardiopulmonary exercise testing (CPET) provides a comprehensive assessment and can unmask the pathophysiological mechanism behind exercise intolerance in gray-zone PASC. This mini-review explores the utility of CPET and aims to provide a comprehensive assessment of PASC by summarizing the current evidence.

Effect of pulmonary hypertension on exercise capacity and gas exchange in patients with chronic obstructive pulmonary disease living at high altitude

Background: Pulmonary hypertension (PH) is associated with decreased exercise tolerance in chronic obstructive pulmonary disease (COPD) patients, but in the altitude the response to exercise in those patients is unknown. Our objective was to compare exercise capacity, gas exchange and ventilatory alterations between COPD patients with PH (COPD-PH) and without PH (COPD-nonPH) residents at high altitude (2640 m). Methods: One hundred thirty-two COPD-nonPH, 82 COPD-PH, and 47 controls were included. Dyspnea by Borg scale, oxygen consumption (VO₂), work rate (WR), ventilatory equivalents (VE/VCO₂), dead space to tidal volume ratio (V_D/V_T), alveolar-arterial oxygen tension gradient (AaPO₂), and arterial-end-tidal carbon dioxide pressure gradient (Pa-ETCO₂) were measurement during a cardiopulmonary exercise test. For comparison of variables between groups, Kruskal-Wallis or one-way ANOVA tests were used, and stepwise regression analysis to test the association between PH and exercise capacity. Results: All COPD patients had a lower exercise capacity and higher PaCO₂, A-aPO₂ and V_D/V_T than controls. The VO₂ % predicted (61.3 ± 20.6 vs 75.3 ± 17.9; p < 0.001) and WR % predicted (65.3 ± 17.9 vs 75.3 ± 17.9; p < 0.001) were lower in COPD-PH than in COPD-nonPH. At peak exercise, dyspnea was higher in COPD-PH (p = 0.011). During exercise, in COPD-PH, the PaO₂ was lower (p < 0.001), and AaPO₂ (p < 0.001), Pa-ETCO₂ (p = 0.033), VE/VCO₂ (p = 0.019), and V_D/V_T (p = 0.007) were higher than in COPD-nonPH. In the multivariate analysis, PH was significantly associated with lower peak VO₂ and WR (p < 0.001). Conclusion: In COPD patients residing at high altitude, the presence of PH was an independent factor related to the exercise capacity. Also, in COPD-PH patients there were more dyspnea and alterations in gas exchange during the exercise than in those without PH.

The effect of medium-term recovery status after COVID-19 illness on cardiopulmonary exercise capacity in a physically active adult population

A failure to fully recover following coronavirus disease 2019 (COVID-19) may have a profound impact on high-functioning populations ranging from frontline emergency services to professional or amateur/recreational athletes. The aim of the study is to describe the medium-term cardiopulmonary exercise profiles of individuals with “persistent symptoms” and individuals who feel “recovered” after hospitalization or mild-moderate community infection following COVID-19 to an age, sex, and job-role matched control group. A total of 113 participants underwent cardiopulmonary functional tests at a mean of 159 ± 7 days (∼5 mo) following acute illness; 27 hospitalized with persistent symptoms (hospitalized-symptomatic), 8 hospitalized and now recovered (hospitalized-recovered); 34 community managed with persistent symptoms (community-symptomatic); 18 community managed and now recovered (community-recovered); and 26 controls. Hospitalized groups had the least favorable body composition (body mass, body mass index, and waist circumference) compared with controls. Hospitalized-symptomatic and community-symptomatic individuals had a lower oxygen uptake (V̇o₂) at peak exercise (hospitalized-symptomatic, 29.9 ± 5.0 mL/kg/min; community-symptomatic, 34.4 ± 7.2 mL/kg/min; vs. control 43.9 ± 3.1 mL/kg/min, both P < 0.001). Hospitalized-symptomatic individuals had a steeper V̇e/V̇co₂ slope (lower ventilatory efficiency) (30.5 ± 5.3 vs. 25.5 ± 2.6, P = 0.003) versus. controls. Hospitalized-recovered had a significantly lower oxygen uptake at peak (32.6 ± 6.6 mL/kg/min vs. 43.9 ± 13.1 mL/kg/min, P = 0.015) compared with controls. No significant differences were reported between community-recovered individuals and controls in any cardiopulmonary parameter. In conclusion, medium-term findings suggest that community-recovered individuals did not differ in cardiopulmonary fitness from physically active healthy controls. This suggests their readiness to return to higher levels of physical activity. However, the hospitalized-recovered group and both groups with persistent symptoms had enduring functional limitations, warranting further monitoring, rehabilitation, and recovery.

NEW & NOTEWORTHY At 5 mo postinfection, community-treated individuals who feel recovered have comparable cardiopulmonary exercise profiles to the physically trained and active controls, suggesting a readiness to return to higher intensity/volumes of exercise. However, both symptomatic groups and the hospital-recovered group have persistent functional limitations when compared with active controls, supporting the requirement for ongoing monitoring, rehabilitation, and recovery.

Prediction of peak oxygen uptake from 6-minute walk test in pulmonary hypertension

Maximal oxygen uptake (V′_O2max), assessed by cardiopulmonary exercise testing (CPET), is an important parameter for risk assessment in patients with pulmonary hypertension (PH). However, CPET may not be available for all PH patients. Thus, we aimed to test previously published predictive models of V′_O2max from the 6-min walk distance (6MWD) for their accuracy and to create a new model.

We tested four models (two by Ross et al. (2010), one by Miyamoto et al. (2000) and one by Zapico et al. (2019)). To derive a new model, data were split into a training and testing dataset (70:30) and step-wise linear regression was performed. To compare the different models, the standard error of the estimate (SEE) was calculated and the models graphically compared by Bland–Altman plots. Sensitivity and specificity for correct prediction into low-risk classification (V′_O2max >15 mL/min/kg) was calculated for all models.

A total of 276 observations were included in the analysis (194/82 training/testing dataset); 6MWD and V′_O2max were significantly correlated (r=0.65, p<0.001). Linear regression showed significant correlation of 6MWD, weight and heart rate response (HRR) with V′_O2max and the best fitting prediction equation was: V′_O2max = 1.83 + 0.031 × 6MWD (m) – 0.023 × weight (kg) – 0.015 × HRR (bpm). SEEs for the different models were 3.03, 3.22, 4.36 and 3.08 mL/min/kg for the Ross et al., Miyamoto et al., Zapico et al. models and the new model, respectively. Predicted mean V′_O2max was 16.5 mL/min/kg (versus observed 16.1 mL/min/kg).

6MWD and V′_O2max reveal good correlation in all models. However, the accuracy of all models is inadequate for clinical use. Thus, CPET and 6MWD both remain valuable risk assessment tools in the management of PH.

Although maximal oxygen uptake and the 6-min walk distance show good correlation in pulmonary hypertension, all predictive models are of inadequate accuracy for clinical use and cardiopulmonary exercise testing remains an irreplaceable toolhttps://bit.ly/33HBQFk

Circulating Blood-Based Biomarkers in Pulmonary Hypertension

Pulmonary hypertension (PH) is a serious hemodynamic condition, characterized by increased pulmonary vascular resistance (PVR), leading to right heart failure (HF) and death when not properly treated. The prognosis of PH depends on etiology, hemodynamic and biochemical parameters, as well as on response to specific treatment. Biomarkers appear to be useful noninvasive tools, providing information about the disease severity, treatment response, and prognosis. However, given the complexity of PH, it is impossible for a single biomarker to be adequate for the broad assessment of patients with different types of PH. The search for novel emerging biomarkers is still ongoing, resulting in a few potential biomarkers mirroring numerous pathophysiological courses. In this review, markers related to HF, myocardial remodeling, inflammation, hypoxia and tissue damage, and endothelial and pulmonary smooth muscle cell dysfunction are discussed in terms of diagnosis and prognosis. Extracellular vesicles and other markers with complex backgrounds are also reviewed. In conclusion, although many promising biomarkers have been identified and studied in recent years, there are still insufficient data on the application of multimarker strategies for monitoring and risk stratification in PH patients.

Skeletal muscle deficits are associated with worse exercise performance in pediatric pulmonary hypertension

BACKGROUND

Skeletal muscle deficits are associated with worse exercise performance in adults with pulmonary hypertension (PH) but the impact is poorly understood in pediatric PH.

OBJECTIVE

To study muscle deficits, physical inactivity, and performance on cardiopulmonary exercise test (CPET) and exercise cardiac magnetic resonance (eCMR) in pediatric PH.

METHODS

Youth 8-18 years participated in a prospective, cross-sectional study including densitometry (DXA) for measurement of leg lean mass Z-score (LLMZ), handheld dynamometer with generation of dominant and non-dominant handgrip Z-scores, Physical Activity Questionnaire (PAQ), CPET, and optional eCMR. CPET parameters were expressed relative to published reference values. CMR protocol included ventricular volumes and indexed systemic flow at rest and just after supine ergometer exercise. Relationships between LLMZ, PAQ score, and exercise performance were assessed by Pearson correlation and multiple linear regression.

RESULTS

There were 25 participants (13.7 ± 2.8 years, 56% female, 64% PH Group 1, 60% functional class I); 12 (48%) performed both CPET and eCMR. Mean LLMZ (-0.96 ± 1.14) was associated with PAQ score (r = 50, p = 0.01) and with peak oxygen consumption (VO₂) (r = 0.74, p = < 0.001), VO₂ at anaerobic threshold (r = 0.65, p < 0.001), and peak work rate (r = 0.64, p < 0.01). Higher handgrip Z-scores were associated with better CPET and eCMR performance. On regression analysis, LLMZ and PAQ score were positively associated with peak VO₂, while handgrip Z-score and PAQ score were positively associated with peak work rate.

CONCLUSION

Muscle mass and strength are positively associated with exercise performance in pediatric PH. Future studies should determine the effect of rehabilitation programs on muscle properties and exercise performance.

Respiratory system as the main determinant of dyspnea in patients with pulmonary hypertension

Dyspnea on exertion is a devastating symptom, commonly observed in patients with pulmonary hypertension (PH). The pathophysiology of dyspnea in these patients has been mainly attributed to cardiovascular determinants and isolated abnormalities of the respiratory system during exercise, neglecting the contribution of the control of the breathing system. The aim of this review is to provide a novel approach to the interpretation of dyspnea in patients with PH, focused on the impact of the control of the breathing system during exercise. Exercise through multiple mechanisms affects the (1) ventilatory demands, as dictated by respiratory center activity, (2) actual ventilation, and (3) metabolic hyperbola. In patients with PH, exertional dyspnea can be explained by exercise-induced alterations in these variables. Compared to healthy subjects, at a given CO2 production during exercise, ventilatory demands in patients with PH are higher due to metabolic acidosis (early reaching the anaerobic threshold), hypoxemia, and excessive upward movement of metabolic hyperbola owing to abnormal exercise response of dead space to tidal volume ratio. Simultaneously, dynamic hyperinflation and respiratory muscles weakness decreases the actual ventilation for a given respiratory center activity, creating a dissociation between demands and ventilation. Consequently, a progressive increase in ventilatory demands and respiratory center activity occurs during exercise. The forebrain projection of high respiratory center activity causes exertional dyspnea despite the relatively low ventilation and significant ventilatory reserve. This type of analysis suggests that the respiratory system is the main determinant of exertional dyspnea in patients with PH, with the cardiovascular system being an indirect contributor.

Validity of the ESC Risk Assessment in Idiopathic Pulmonary Arterial Hypertension in China

Background: The 2015 European pulmonary hypertension (PH) guidelines recommend a risk stratification strategy for pulmonary arterial hypertension (PAH). We aimed to investigate the validation and potential prognostic information in Chinese patients. Methods: The risk assessment variables proposed by the PH guidelines were performed by using the WHO function class, 6-min walking distance, brain natriuretic peptide or its N-terminal fragment, right arterial pressure, cardiac index, mixed venous saturation, right atrium area, pericardial effusion, peak oxygen consumption, and ventilatory equivalents for carbon dioxide. An abbreviated version also was applied. Results: A total of 392 patients with idiopathic PAH (IPAH) were enrolled between 2009 and 2018. After a median interval of 13 months, re-evaluation assessments were available for 386 subjects. The PAH guidelines risk tool may effectively discriminate three risk groups and mortality (p < 0.001) both at the baseline and re-evaluation. Meanwhile, its simplified risk version was valid for baseline and accurately predicted the risk of death in all the risk groups (p < 0.001). At the time of re-evaluation, the percentage of low-risk group has an increase, but a greater proportion achieved the high-risk group and a lesser proportion maintained in the intermediate-risk group. Conclusion: The 2015 European PH guidelines and its simplified version risk stratification assessment present an effective discrimination of different risk groups and accurate mortality estimates in Chinese patients with IPAH. Changes of risk proportion at re-evaluation implicated that natural treatment decisions may not be consistently with goal-oriented treatment strategy.

Cardiopulmonary exercise testing and pulmonary function testing for predicting the severity of CTEPH

Background

Cardiopulmonary exercise testing (CPET) and pulmonary function testing (PFT) are noninvasive methods to evaluate the respiratory and circulatory systems. This research aims to evaluate and monitor chronic thromboembolic pulmonary hypertension (CTEPH) noninvasively and effectively by these two methods. Moreover, the research assesses the predictive value of CPET and PFT parameters for severe CTEPH.

Methods

We used data from 86 patients with CTEPH (55 for test set, and 31 for validation set) at the Shanghai Pulmonary Hospital Affiliated to Tongji University. The clinical, PFT and CPET data of CTEPH patients of different severity classified according to pulmonary artery pressure (PAP) (mm Hg) were collected and compared. Logistic regression analysis was performed to appraise the predictive value of each PFT and CPET parameter for severe CTEPH. The performance of CPET parameters for predicting severe CTEPH was determined by receiver operating characteristic (ROC) curves and calibration curves.

Results

Data showed that minute ventilation at anaerobic threshold (VE @ AT) (L/min) and oxygen uptake at peak (VO₂ @ peak) (mL/kg/min) were independent predictors for severe CTEPH classified according to PAP (mm Hg). Additionally, the efficacy of VE @ AT (L/min) and VO₂ @ peak (mL/kg/min) in identifying severe CTEPH was found to be moderate with the area under ROC curve (AUC) of 0.769 and 0.740, respectively. Furthermore, the combination of VE @ AT (L/min) and VO₂ @ peak (mL/kg/min) had a moderate utility value in identifying severe CTEPH with the AUC of 0.843.

Conclusion

Our research suggests that CPET and PFT can noninvasively and effectively evaluate, monitor and predict the severity of CTEPH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01668-3.

Impact of cyanosis on ventilatory responses during stair climb exercise in Eisenmenger syndrome and idiopathic pulmonary arterial hypertension

Studies assessing exercise ventilatory responses during real-life exercise in pulmonary arterial hypertension (PAH) which include patients with cyanotic congenital heart disease are scarce. We assessed the ventilatory response to stairclimbing in patients with idiopathic PAH (IPAH) and congenital heart disease-associated PAH with Eisenmenger (EIS) physiology compared to healthy controls. Fifteen adults with IPAH, six EIS and 15 age and body mass index (BMI) matched controls were prospectively recruited. Participants completed spirometry and a self-paced stair-climb (48 steps) with portable cardiopulmonary exercise testing (CPET) equipment in-situ. Borg dyspnoea scores were measured at rest and on stair-climb cessation. Both IPAH and EIS groups had amplified ventilatory responses compared to Controls. The rate of increase in minute ventilation (VE) was exaggerated in EIS driven by an early increase in tidal volume (Tv) and more gradual increase in respiratory rate (RR). Peak Tv, RR, Tv: forced vital capacity (FVC) ratio, VE/VCO₂ slope and stairclimb duration were significantly higher in EIS and IPAH compared to controls despite similar baseline spirometry and change in oxygen uptake on exercise. A decline in end-tidal carbon dioxide (CO₂) and arterial oxygen saturations in early exercise distinguished EIS and IPAH patients. Significant correlations were observed between peak exercise Borg score and stair-climb time (r = 0.73, p = 0.002), peak end-tidal CO₂ (r = -0.73, p = 0.001), peak VE (r = 0.53, p = 0.008), peak RR (r = 0.42, p = 0.011) and VE/VCO₂ slope (r = 0.54, p = 0.001). Patients with IPAH and EIS have exaggerated ventilatory responses to stair-climbing compared to the controls with more severe levels of dyspnoea perception in Eisenmenger syndrome for equivalent oxygen uptake and work.

Oates K, J. Fletcher A, P. Sylvester K. The association of six-minute walk work and other clinical measures to cardiopulmonary exercise test parameters in pulmonary vascular disease

INTRODUCTION

In pulmonary vascular disease exercise, abnormalities can include reduced exercise capacity, reduced oxygen pulse and elevated VE/VCO2. The association of clinical measures such as six-minute walk work, haemodynamics, lung function and echocardiogram to peak VO2, O2 pulse and VE/VCO2 has not been fully investigated in pulmonary vascular disease.

AIMS

To determine the relationship of six-minute walk work and other clinical measures to peak VO2, peak O2 pulse and VE/VCO2. Additionally, to investigate the ability to predict peak VO2 from six-minute walk work and other clinical parameters.

METHODS

Clinical data was retrospectively analysed from 63 chronic thromboembolic pulmonary hypertension (CTEPH) and 54 chronic thromboembolic disease (CTED) patients. Six-minute walk test measures, haemodynamics, lung function and echocardiographic measures were correlated with peak VO2, peak O2 pulse and VE/VCO2. Predictive equations were developed to predict peak V̇O2 in both CTEPH and CTED cohorts and subsequently validated.

RESULTS

A number of clinical parameters correlated to peak VO2, peak O2 pulse and VE/VCO2. Six-minute walk work and transfer factor for carbon monoxide demonstrated the strongest correlation to peak VO2 and peak O2 pulse. The validation of the predictive equations showed a variable level of agreement between measured peak VO2 and calculated peak VO2 from the predictive equations.

CONCLUSION

Six-minute walk work and additionally a number of clinical test parameters were associated to peak VO2, peak O2 pulse and VE/VCO2. Six-minute walk work and transfer factor for carbon monoxide were particularly highly correlated to peak VO2 and similarly to peak oxygen pulse. The validation of the predictive equations showed a variable level of agreement and therefore may have limited clinical applicability.

Ventilatory efficiency in pulmonary vascular diseases

Cardiopulmonary exercise testing (CPET) is a frequently used tool in the differential diagnosis of dyspnoea. Ventilatory inefficiency, defined as high minute ventilation (V′_E) relative to carbon dioxide output (V′_CO2), is a hallmark characteristic of pulmonary vascular diseases, which contributes to exercise intolerance and disability in these patients. The mechanisms of ventilatory inefficiency are multiple and include high physiologic dead space, abnormal chemosensitivity and an altered carbon dioxide (CO₂) set-point. A normal V′_E/V′_CO2 makes a pulmonary vascular disease such as pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH) unlikely. The finding of high V′_E/V′_CO2 without an alternative explanation should prompt further diagnostic testing to exclude PAH or CTEPH, particularly in patients with risk factors, such as prior venous thromboembolism, systemic sclerosis or a family history of PAH. In patients with established PAH or CTEPH, the V′_E/V′_CO2 may improve with interventions and is a prognostic marker. However, further studies are needed to clarify the added value of assessing ventilatory inefficiency in the longitudinal follow-up of patients.

Ventilatory inefficiency is a hallmark feature of PH that reflects abnormal ventilation/perfusion matching, chemosensitivity and an altered CO₂ set-point. Minute ventilation/CO₂ production is useful in the diagnosis, management and prognostication of PH.https://bit.ly/3jnNdUG

Role of Selexipag in Chronic Obstructive Pulmonary Disease (COPD) Patients With Out-of-Proportion Pulmonary Hypertension

Pulmonary hypertension (PH) in patients with chronic obstructive pulmonary disease (COPD) is associated with an increase in the risk of COPD exacerbation, increased hospitalization, and worse survival in this patient population. No specific treatment is available for PH in COPD. However, reported out-of-proportion PH may benefit from a certain type of treatment. This study shows that the use of selexipag in the treatment of out-of-proportion PH in COPD patients was associated with an improvement in functional status evaluated by a six-minute walk test (6MWT) and a mean pulmonary artery pressure at 6 +/- 2 months of treatment.

Maximal Exercise Testing Using the Incremental Shuttle Walking Test Can Be Used to Risk-Stratify Patients with Pulmonary Arterial Hypertension

Rationale: Exercise capacity predicts mortality in pulmonary arterial hypertension (PAH), but limited data exist on the routine use of maximal exercise testing.

Objectives: This study evaluates a simple-to-perform maximal test (the incremental shuttle walking test) and its use in risk stratification in PAH.

Methods: Consecutive patients with pulmonary hypertension were identified from the ASPIRE (Assessing the Spectrum of Pulmonary hypertension Identified at a REferral centre) registry (2001–2018). Thresholds for levels of risk were identified at baseline and tested at follow-up, and their incorporation into current risk stratification approaches was assessed.

Results: Of 4,524 treatment-naive patients with pulmonary hypertension who underwent maximal exercise testing, 1,847 patients had PAH. A stepwise reduction in 1-year mortality was seen between levels 1 (≤30 m; 32% mortality) and 7 (340–420 m; 1% mortality) with no mortality for levels 8–12 (≥430 m) in idiopathic and connective tissue disease–related PAH. Thresholds derived at baseline of ≤180 m (>10%; high risk), 190–330 m (5–10%; intermediate risk), and ≥340 m (<5%; low risk of 1-yr mortality) were applied at follow-up and also accurately identified levels of risk. Thresholds were incorporated into the REVEAL (Registry to Evaluate Early and Long-Term Pulmonary Arterial Hypertension Disease Management) 2.0 risk score calculator and French low-risk approach to risk stratification, and distinct categories of risk remained.

Conclusions: We have demonstrated that maximal exercise testing in PAH stratifies mortality risk at baseline and follow-up. This study highlights the potential value of the incremental shuttle walking test as an alternative to the 6-minute walking test, combining some of the advantages of maximal exercise testing and maintaining the simplicity of a simple-to-perform field test.

Exercise intolerance in pulmonary arterial hypertension: insight into central and peripheral pathophysiological mechanisms

Exercise intolerance is a cardinal symptom of pulmonary arterial hypertension (PAH) and strongly impacts patients' quality of life (QoL). Although central cardiopulmonary impairments limit peak oxygen consumption (V' O2peak ) in patients with PAH, several peripheral abnormalities have been described over the recent decade as key determinants in exercise intolerance, including impaired skeletal muscle (SKM) morphology, convective O2 transport, capillarity and metabolism indicating that peripheral abnormalities play a greater role in limiting exercise capacity than previously thought. More recently, cerebrovascular alterations potentially contributing to exercise intolerance in patients with PAH were also documented. Currently, only cardiopulmonary rehabilitation has been shown to efficiently improve the peripheral components of exercise intolerance in patients with PAH. However, more extensive studies are needed to identify targeted interventions that would ultimately improve patients' exercise tolerance and QoL. The present review offers a broad and comprehensive analysis of the present literature about the complex mechanisms and their interactions limiting exercise in patients and suggests several gaps in knowledge that need to be addressed in the future for a better understanding of exercise intolerance in patients with PAH.

ERS statement on chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare complication of acute pulmonary embolism, either symptomatic or not. The occlusion of proximal pulmonary arteries by fibrotic intravascular material, in combination with a secondary microvasculopathy of vessels <500 µm, leads to increased pulmonary vascular resistance and progressive right heart failure. The mechanism responsible for the transformation of red clots into fibrotic material remnants has not yet been elucidated. In patients with pulmonary hypertension, the diagnosis is suspected when a ventilation/perfusion lung scan shows mismatched perfusion defects, and confirmed by right heart catheterisation and vascular imaging. Today, in addition to lifelong anticoagulation, treatment modalities include surgery, angioplasty and medical treatment according to the localisation and characteristics of the lesions.This statement outlines a review of the literature and current practice concerning diagnosis and management of CTEPH. It covers the definitions, diagnosis, epidemiology, follow-up after acute pulmonary embolism, pathophysiology, treatment by pulmonary endarterectomy, balloon pulmonary angioplasty, drugs and their combination, rehabilitation and new lines of research in CTEPH.It represents the first collaboration of the European Respiratory Society, the International CTEPH Association and the European Reference Network-Lung in the pulmonary hypertension domain. The statement summarises current knowledge, but does not make formal recommendations for clinical practice.

Postpulmonary embolism syndrome

PURPOSE OF REVIEW

It is now recognized that more than half of patients with acute pulmonary embolism (APE) will have persistent symptoms beyond 3 months after their initial event. Persistent symptoms are referred to as post-PE syndrome, an umbrella term that covers a spectrum of patient complaints and underlying pathologies. Data published over the last 5 years have added significantly to our understanding of this syndrome and its management.

RECENT FINDINGS

Underlying pathologies linked to post-PE syndrome include chronic thromboembolic pulmonary hypertension (CTEPH), chronic thromboembolic disease (CTED), cardiac dysfunction, and deconditioning. Treatment for post-PE syndrome will depend on the underlying causative pathologies found. Evaluation and treatment for CTEPH is well defined, but less than 10% of patients with post-PE syndrome will qualify as having this diagnosis.

SUMMARY

A large percentage of patients will experience post-PE syndrome following APE. Strategies for identification and treatment for some pathologies are well studied, but the majority of patients will have subtle abnormalities on imaging and functional testing for which diagnostic criteria and management are not well defined. A number of active studies are designed to help optimize the management of post-PE syndrome and should help us improve intermediate and long-term outcomes for patients following APE.

Exercise Ventilatory Inefficiency in Post-COVID-19 Syndrome: Insights from a Prospective Evaluation

Introduction: Coronavirus disease 2019 (COVID-19) is a systemic disease characterized by a disproportionate inflammatory response in the acute phase. This study sought to identify clinical sequelae and their potential mechanism. Methods: We conducted a prospective single-center study (NCT04689490) of previously hospitalized COVID-19 patients with and without dyspnea during mid-term follow-up. An outpatient group was also evaluated. They underwent serial testing with a cardiopulmonary exercise test (CPET), transthoracic echocardiogram, pulmonary lung test, six-minute walking test, serum biomarker analysis, and quality of life questionaries. Results: Patients with dyspnea (n = 41, 58.6%), compared with asymptomatic patients (n = 29, 41.4%), had a higher proportion of females (73.2 vs. 51.7%; p = 0.065) with comparable age and prevalence of cardiovascular risk factors. There were no significant differences in the transthoracic echocardiogram and pulmonary function test. Patients who complained of persistent dyspnea had a significant decline in predicted peak VO₂ consumption (77.8 (64–92.5) vs. 99 (88–105); p < 0.00; p < 0.001), total distance in the six-minute walking test (535 (467–600) vs. 611 (550–650) meters; p = 0.001), and quality of life (KCCQ-23 60.1 ± 18.6 vs. 82.8 ± 11.3; p < 0.001). Additionally, abnormalities in CPET were suggestive of an impaired ventilatory efficiency (VE/VC_O2 slope 32 (28.1–37.4) vs. 29.4 (26.9–31.4); p = 0.022) and high PET_CO2 (34.5 (32–39) vs. 38 (36–40); p = 0.025). Interpretation: In this study, >50% of COVID-19 survivors present a symptomatic functional impairment irrespective of age or prior hospitalization. Our findings suggest a potential ventilation/perfusion mismatch or hyperventilation syndrome.

Effect of pulmonary hypertension on exercise tolerance in patients with COPD: a prognostic systematic review and meta-analysis

Background

Pulmonary hypertension (PH) is a frequent complication in patients with COPD.

Objective

To determine if, in patients with COPD, the presence of PH decreases exercise tolerance.

Methods

We included studies that analysed exercise tolerance using a cardiopulmonary exercise test (CPET) in patients with COPD with PH (COPD-PH) and without PH (COPD-nonPH). Two independent reviewers analysed the studies, extracted the data and assessed the quality of the evidence.

Results

Of the 4915 articles initially identified, seven reported 257 patients with COPD-PH and 404 patients with COPD-nonPH. The COPD-PH group showed differences in peak oxygen consumption (V′_O2peak), −3.09 mL·kg⁻¹·min⁻¹ (95% CI −4.74 to −1.43, p=0.0003); maximum workload (W_max), −20.5 W (95% CI −34.4 to −6.5, p=0.004); and oxygen pulse (O₂ pulse), −1.24 mL·beat⁻¹ (95% CI −2.40 to −0.09, p=0.03), in comparison to the group with COPD-nonPH. If we excluded studies with lung transplant candidates, the sensitivity analyses showed even bigger differences: V′_O2, −4.26 mL·min⁻¹·kg⁻¹ (95% CI −5.50 to −3.02 mL·kg⁻¹·min⁻¹, p<0.00001); W_max, −26.6 W (95% CI −32.1 to −21.1 W, p<0.00001); and O₂ pulse, −2.04 mL·beat⁻¹ (95% CI −2.92 to −1.15 mL·beat⁻¹, p<0.0001).

Conclusion

Exercise tolerance was significantly lower in patients with COPD-PH than in patients with COPD-nonPH, particularly in nontransplant candidates.

The V′_O2peak, Wmax and O₂ pulse values were significantly lower in patients with COPD-PH than in patients with COPD-nonPH, particularly in nontransplant candidateshttps://bit.ly/3s5dtJ9

Outcomes of patients with decreased arterial oxyhaemoglobin saturation on pulmonary arterial hypertension drugs

RATIONALE

Drugs approved for the treatment of pulmonary arterial hypertension (PAH) improve long-term outcomes. These drugs have pulmonary vasodilator properties which may potentially cause a decrease in arterial oxyhaemoglobin saturation (SaO₂) in some patients.

OBJECTIVES

The present retrospective study of the French PAH Registry aimed to describe clinical characteristics and outcomes of patients showing a ≥3% decrease in SaO₂ while treated with PAH drugs.

METHODS

We reviewed 719 PAH patients. The exclusion criteria were PAH associated with congenital heart disease and PAH with overt features of venous/capillaries involvement.

MAIN RESULTS

One hundred and seventy-three (24%) patients had a ≥3% decrease in SaO₂. At diagnosis, they were older, with a lower diffusion capacity for carbon monoxide and a shorter 6-minute walk distance, when compared to those who did not display a ≥3% decrease in SaO₂. The percentage of patients meeting the ESC/ERS low risk criteria at re-evaluation was significantly lower in those with a ≥3% decrease in SaO₂ and more patients started long-term oxygen therapy in this group (16% versus 5%, p<0.001). A≥3% decrease in SaO₂ was associated with a poorer survival (Hazard Ratio 1.81:95% confidence interval 1.43-2.34; p<0.0001). In a multivariate Cox analysis, a ≥3% decrease in SaO₂ was a prognostic factor independent of age at diagnosis and ESC/ERS risk stratification at follow-up.

CONCLUSIONS

When treated with PAH drugs, a large subset of patients experience a≥3% decrease in SaO₂, which is associated with worst long-term outcomes and reduced survival.

Cardiopulmonary Exercise Testing in Combined Pulmonary Fibrosis and Emphysema

BACKGROUND

Combined pulmonary fibrosis and emphysema (CPFE) is a distinct entity among fibrosing lung diseases with a high risk for lung cancer and pulmonary hypertension (PH). Notably, concomitant PH was identified as a negative prognostic indicator that could help with early diagnosis to provide important information regarding prognosis.

OBJECTIVES

The current study aimed to determine whether cardiopulmonary exercise testing (CPET) can be helpful in differentiating patients having CPFE with and without PH.

METHODS

Patients diagnosed with CPFE in 2 German cities (Hemer and Greifswald) over a period of 10 years were included herein. CPET parameters, such as peak oxygen uptake (peak VO2), functional dead space ventilation (VDf/VT), alveolar-arterial oxygen difference (AaDO2), arterial-end-tidal CO2 difference [P(a-ET)CO2] at peak exercise, and the minute ventilation-carbon dioxide production relationship (VE/VCO2 slope), were compared between patients with and without PH.

RESULTS

A total of 41 patients with CPET (22 with PH, 19 without PH) were analyzed. Right heart catheterization was performed in 15 of 41 patients without clinically relevant complications. Significant differences in peak VO2 (861 ± 190 vs. 1,397 ± 439 mL), VO2/kg body weight/min (10.8 ± 2.6 vs. 17.4 ± 5.2 mL), peak AaDO2 (72.3 ± 7.3 vs. 46.3 ± 14.2 mm Hg), VE/VCO2 slope (70.1 ± 31.5 vs. 39.6 ± 9.6), and peak P(a-ET)tCO2 (13.9 ± 3.5 vs. 8.1 ± 3.6 mm Hg) were observed between patients with and without PH (p < 0.001). Patients with PH had significantly higher VDf/VT at rest, VT1, and at peak exercise (65.6 ± 16.8% vs. 47.2 ± 11.6%; p < 0.001) than those without PH. A cutoff value of 44 for VE/VCO2 slope had a sensitivity and specificity of 94.7 and 72.7%, while a cutoff value of 11 mm Hg for P(a-ET)CO2 in combination with peak AaDO2 >60 mm Hg had a specificity and sensitivity of 95.5 and 84.2%, respectively. Combining peak AaDO2 >60 mm Hg with peak VO2/body weight/min <16.5 mL/kg/min provided a sensitivity and specificity of 100 and 95.5%, respectively.

CONCLUSION

This study provided initial data on CPET among patients having CPFE with and without PH. CPET can help noninvasively detect PH and identify patients at risk. AaDO2 at peak exercise, VE/VCO2 slope, peak P(a-ET)CO2, and peak VO2 were parameters that had high sensitivity and, when combined, high specificity.

The predictive value of minute ventilation versus carbon dioxide production in pulmonary hypertension associated with left heart disease

Background

The aim of the present study was to investigate the role of key cardiopulmonary exercise testing (CPET) parameters in the identification of pre-capillary components in patients with pulmonary hypertension associated with left heart disease (PH-LHD), and to evaluate their correlations with hemodynamic parameters.

Methods

Ninety patients with PH-LHD underwent right-heart catheterization, echocardiography, and CPET. The differences in related indexes between a combined post- and pre-capillary PH (Cpc-PH) group (n=47) and an isolated post-capillary PH (Ipc-PH) group (n=43) were compared. Correlation analysis was performed. Logistic regression and receiver operator characteristic (ROC) analyses were performed to assess the ability of CPET variables to distinguish patients with Cpc-PH from those with Ipc-PH.

Results

The hemodynamics, hyperventilation and right ventricular function of Cpc-pH group were worse than those of Ipc-pH group. The parameters related to minute ventilation versus carbon dioxide production (VE/VCO₂) played a significant role in the differentiation of Cpc-PH and Ipc-PH, and had a moderate positive correlation with pulmonary vascular resistance (PVR). Univariate and multivariate logistic analyses showed that lowest percentage of VE/VCO₂ in predicted value (VE/VCO₂%pred) was the single best predictor of Cpc-PH, and the area under ROC curve also confirmed that lowest VE/VCO₂%pred (≥137%) could serve as a novel diagnostic marker for Cpc-PH. On the basis of this lowest VE/VCO₂%pred threshold, patients were divided into two groups. Most hemodynamic parameters were worse in patients with a lowest VE/VCO₂%pred ≥137%.

Conclusions

VE/VCO₂-related parameters are powerful prognosticators for the presence of pre-capillary components in patients with PH-LHD, especially lowest VE/VCO₂%pred.

Roles of periodic breathing and isocapnic buffering period during exercise in heart failure

In heart failure, exercise - induced periodic breathing and end tidal carbon dioxide pressure value during the isocapnic buffering period are two features identified at cardiopulmonary exercise testing strictly related to sympathetic activation. In the present review we analysed the physiology behind periodic breathing and the isocapnic buffering period and present the relevant prognostic value of both periodic breathing and the presence/absence of the identifiable isocapnic buffering period.

Exercise Capacity and Quality of Life in Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disease with a high mortality rate that can be divided into different groups according to etiology and prognosis. Few studies have investigated differences in the exercise capacity and quality of life (QOL) among the different groups of PAH patients. Therefore, we aimed to (1) compare the hemodynamic exercise responses between patients with idiopathic pulmonary arterial hypertension (IPAH) and PAH associated with other diseases (APAH), and (2) determine the factors associated with exercise capacity in patients with PAH.

METHODS

Six patients diagnosed with IPAH and eight with APAH [congenital heart disease (CHD)-dominant PAH] were included in this study. The main outcome measures included body composition, exercise capacity, hemodynamic measurements, physical activity levels, fatigue severity, and QOL.

RESULTS

The CHD-dominant PAH group had a significantly lower predicted peak oxygen consumption (VO2pred %), pressure of end-tidal carbon dioxide at the peak and at anaerobic threshold (PETCO2peak and PETCO2@AT), and significantly elevated ventilatory equivalent (VE/VCO2slope and VE/VCO2@AT) compared with the IPAH group. Multiple regression analysis indicated that PETCO2@AT was significantly associated with either VO2peak (β = 0.805, adjusted R2 = 0.619, p = 0.001) or 6-minute walk distance (β = 0.816, adjusted R2 = 0.638, p < 0.001).

CONCLUSIONS

Patients with CHD-dominant PAH had poor exercise capacity and exercise responses compared to those with IPAH. Evaluating exercise capacity and the patient response to exercise using cardiopulmonary exercise testing is increasingly important in view of the etiology of PAH.

The value of cardiopulmonary exercise testing in the diagnosis of pulmonary hypertension

Background

Cardiopulmonary exercise testing (CPET) continuously analyzes the gas exchange of patients during rest, exercise, recovery, and simultaneously records the response of the cardiopulmonary system. This study aimed to observe the characteristics of CPET in patients with pulmonary hypertension (PH) and to explore the cutoff value of CPET variables in detecting PH. The diagnostic value of CPET was also investigated in a subgroup of patients who had an incorrect or missed diagnosis of PH by echocardiography.

Methods

Treatment-naïve patients with suspected PH who were admitted to Fuwai Hospital from January 2017 to August 2018 were consecutively enrolled. The gold standard criterion for PH was defined as mean pulmonary artery pressure (mPAP) ≥25 mmHg at rest, measured by right heart catheterization. General clinical materials, echocardiography, hemodynamics, and CPET data of the patients were collected and compared between groups. Logistic regression analyses were performed to explore the CPET variables that were independently associated with PH. To further validate the value of CPET for diagnosing PH, the CPET cutoff values obtained from receiver operating characteristic (ROC) curve analysis were used in patients who had an incorrect or missed diagnosis by echocardiography.

Results

Five hundred and fifty-nine patients were included in the study. Among them, patients with PH had significantly poorer CPET variables. Multivariate logistic regression analysis showed that peak work rate (WR), peak oxygen uptake (VO₂), and end-tidal carbon dioxide partial pressure (PetCO₂) at the anaerobic threshold (AT) were independently associated with PH after adjustment for age, sex, and body mass index. The above three CPET variables were all negatively correlated with mPAP. The combined CPET variable including peak WR, peak VO₂ and PetCO₂ at AT had the largest area under the ROC curve for the diagnosis of PH (0.890, 95% CI: 0.852–0.927, P<0.001). The cutoff value was 0.86, and the sensitivity and specificity were 81.8% and 86.5%, respectively. Using this cutoff value, 83.7% of patients who were misdiagnosed and 67.9% of patients who had a missed diagnosis by echocardiography were identified.

Conclusions

PH patients have decreased cardiopulmonary reserve, lower exercise tolerance, and increased ineffective ventilation. The combination of peak WR, peakVO₂, and PetCO₂ at AT had increased sensitivity and specificity for the diagnosis of PH, and increased the specificity for identifying patients who had been misdiagnosed as PH by echocardiography.