Persistent exercise intolerance after pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension

An overview of balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension

INTRODUCTION

Chronic thromboembolic pulmonary hypertension (CTEPH) is a severe and progressive condition caused by unresolved pulmonary arterial obstructions, leading to secondary microvasculopathy and poor hemodynamics. Pulmonary endarterectomy (PEA) is the first-line treatment for operable patients. Balloon pulmonary angioplasty (BPA) has emerged as a promising treatment option for patients considered inoperable due to distal lesions, comorbidities, or residual pulmonary hypertension (PH) after PEA. Following the development of the BPA in safety and efficacy, it has been widely adopted and utilized across the globe.

AREAS COVERED

This review covers the historical development of BPA, its clinical role, and technical methodologies. Medical therapies as an adjunctive role in CTEPH management are also discussed. Finally, we present recent BPA experiences from our institution, highlighting hemodynamic outcomes and survival rates.

EXPERT OPINION

BPA is a transformative treatment for patients with CTEPH, particularly those ineligible for PEA. Procedural refinements have significantly improved safety and efficacy. However, challenges remain, including the standardization of decision-making processes for management and the establishment of optimal treatment goals. Ongoing research continues to refine the role of BPA to improve outcomes and enhance the quality of life for patients with CTEPH.

Long-term effects of pulmonary endarterectomy on pulmonary hemodynamics, cardiac function, and exercise capacity in chronic thromboembolic pulmonary hypertension

BACKGROUND

Long-term changes in exercise capacity and cardiopulmonary hemodynamics after pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH) have been poorly described.

METHODS

We analyzed the data from 2 prospective surgical CTEPH cohorts in Hammersmith Hospital, London, and Amsterdam UMC. A structured multimodal follow-up was adopted, consisting of right heart catheterization, cardiac magnetic resonance imaging, and cardiopulmonary exercise testing before and after PEA. Preoperative predictors of residual pulmonary hypertension (PH; mean pulmonary artery pressure >20 mm Hg and pulmonary vascular resistance ≥2 WU) and long-term exercise intolerance (VO2max <80%) at 18 months were analyzed.

RESULTS

A total of 118 patients (61 from London and 57 from Amsterdam) were included in the analysis. Both cohorts displayed a significant improvement of pulmonary hemodynamics, right ventricular (RV) function, and exercise capacity 6 months after PEA. Between 6 and 18 months after PEA, there were no further improvements in hemodynamics and RV function, but the proportion of patients with impaired exercise capacity was high and slightly increased over time (52%-59% from 6 to 18 months). Long-term exercise intolerance was common and associated with preoperative diffusion capacity for carbon monoxide (DLCO), preoperative mixed venous oxygen saturation, and postoperative PH and right ventricular ejection fraction (RVEF). Clinically significant RV deterioration (RVEF decline >3%; 5 [9%] of 57 patients) and recurrent PH (5 [14%] of 36 patients) rarely occurred beyond 6 months after PEA. Age and preoperative DLCO were predictors of residual PH post-PEA.

CONCLUSIONS

Restoration in exercise tolerance, cardiopulmonary hemodynamics, and RV function occurs within 6 months. No substantial changes occurred between 6 and 18 months after PEA in the Amsterdam cohort. Nevertheless, long-term exercise intolerance is common and associated with postoperative RV function.

Performance-based outcome measures for assessing physical capacity in patients with pulmonary embolism: A scoping review

INTRODUCTION

Up to 50 % of patients surviving a pulmonary embolism (PE) report persisting shortness of breath, reduced physical capacity and psychological distress. As the PE population is heterogeneous compared to other cardiovascular patient groups, outcome measures for assessing physical capacity traditionally used in cardiac populations may not be reliable for the PE population as a whole. This scoping review aims to 1) map performance-based outcome measures (PBOMs) used for assessing physical capacity in PE research, and 2) to report the psychometric properties of the identified PBOMs in a PE population.

METHODS

The review was conducted according to the Joanna Briggs Institute framework for scoping reviews and reported according to the PRISMA-Extension for Scoping Reviews guideline.

RESULTS

The systematic search of five databases identified 4585 studies, of which 243 studies met the inclusion criteria. Of these, 185 studies focused on a subgroup of patients with chronic thromboembolic pulmonary hypertension. Ten different PBOMs were identified in the included studies. The 6-minute walk test (6MWT) and cardiopulmonary exercise test (CPET) were the most commonly used, followed by the (Modified) Bruce protocol and Incremental Shuttle Walk test. No studies reported psychometric properties of any of the identified PBOMs in a PE population.

CONCLUSIONS

Publication of studies measuring physical capacity within PE populations has increased significantly over the past 5-10 years. Still, not one study was identified, reporting the validity, reliability, or responsiveness for any of the identified PBOMs in a PE population. This should be a priority for future research in the field.

[Update in the management of chronic thrombo-embolic pulmonary hypertension]

Chronic thrombo-embolic pulmonary hypertension (CTEPH) is a potentially curable form of pulmonary hypertension (PH) that develops in up to 3% of patients after pulmonary embolism (PE). In these patients, PE does not resolve, leading to organized fibrotic clots, with the development of precapillary PH as a result of the proximal obstruction of the pulmonary arteries. In addition, a distal microvasculopathy may also develop, contributing to the increase of pulmonary vascular resistance. Transthoracic echocardiography is the diagnostic tool that allows to establish the suspicion of PH. Ventilation-perfusion lung scintigraphy is the fundamental tool in the study of patients with suspected CTEPH; if it is normal, virtually rules out the diagnosis. Right heart catheterization is mandatory for the diagnosis of these patients. CTEPH is defined as the existence of symptoms, residual perfusion defects and precapillary PH after a minimum period of three months of anticoagulation. Pulmonary angiography helps determine the extent and surgical accessibility of thromboembolic lesions. CTEPH patients are candidates for long-term anticoagulation. Pulmonary endarterectomy is the treatment of choice, resulting in significant clinical and hemodynamic improvement. About 25% of patients have residual PH post-endarterectomy. Balloon pulmonary angioplasty is an endovascular technique that targets more distal lesions, being potentially useful for patients with inoperable CTEPH or persistent/recurrent PH post-endarterectomy. Both types of patients may also benefit from pharmacological treatment for PH. These three therapies are the cornerstone of CTEPH treatment, which has evolved towards a multimodal approach.

Meijboom L, Symersky P, Winkelman JA, Nossent EJ, Aman J, Bogaard HJ, Vonk Noordegraaf A, van Es J. Patients with CTEPH and mild hemodynamic severity of disease improve to a similar level of exercise capacity after pulmonary endarterectomy compared to patients with severe hemodynamic disease

The correlation between hemodynamics and degree of pulmonary vascular obstruction (PVO) is known to be poor in chronic thromboembolic pulmonary hypertension (CTEPH), which makes the selection of patients eligible for pulmonary endarterectomy (PEA) challenging. It can be postulated that patients with similar PVO but different hemodynamic severity have different postoperative hemodynamics and exercise capacity. Therefore, we aimed to assess the effects of PEA on hemodynamics and exercise physiology in mild and severe CTEPH patients. We retrospectively studied 18 CTEPH patients with a mild hemodynamic profile (mean pulmonary arterial pressure [mPAP] between 25 and 30 mmHg at rest) and CTEPH patients with a more severe hemodynamic profile (mPAP > 30 mmHg), matched by age, gender, and PVO. Cardiopulmonary exercise testing parameters were evaluated at baseline and 18 months following PEA. At baseline, exercise capacity, defined as oxygen uptake, was less severely impaired in the mild CTEPH group compared to the severe CTEPH group. After PEA, in the mild CTEPH group, ventilatory efficiency and oxygen pulse improved significantly (p < 0.05), however, the change in ventilatory efficiency and oxygen pulse was smaller compared to the severe CTEPH group. Only in the severe CTEPH group exercise capacity improved significantly (p < 0.001). Hence, in the present study, postoperative hemodynamic outcome and the CPET-determined recovery of exercise capacity in mild CTEPH patients did not differ from a matched group of severe CTEPH patients.

Right Ventricular Function During Exercise After Pulmonary Endarterectomy for Chronic Thromboembolic Pulmonary Hypertension

Background Pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension improves resting hemodynamics and right ventricular (RV) function. Because exercise tolerance frequently remains impaired, RV function may not have completely normalized after PEA. Therefore, we performed a detailed invasive hemodynamic study to investigate the effect of PEA on RV function during exercise. Methods and Results In this prospective study, all consenting patients with chronic thromboembolic pulmonary hypertension eligible for surgery and able to perform cycle ergometry underwent cardiac magnetic resonance imaging, a maximal cardiopulmonary exercise test, and a submaximal invasive cardiopulmonary exercise test before and 6 months after PEA. Hemodynamic assessment and analysis of RV pressure curves using the single-beat method was used to determine load-independent RV contractility (end systolic elastance), RV afterload (arterial elastance), RV-arterial coupling (end systolic elastance-arterial elastance), and stroke volume both at rest and during exercise. RV rest-to-exercise responses were compared before and after PEA using 2-way repeated-measures analysis of variance with Bonferroni post hoc correction. A total of 19 patients with chronic thromboembolic pulmonary hypertension completed the entire study protocol. Resting hemodynamics improved significantly after PEA. The RV exertional stroke volume response improved 6 months after PEA (79±32 at rest versus 102±28 mL during exercise; P<0.01). Although RV afterload (arterial elastance) increased during exercise, RV contractility (end systolic elastance) did not change during exercise either before (0.43 [0.32-0.58] mm Hg/mL versus 0.45 [0.22-0.65] mm Hg/mL; P=0.6) or after PEA (0.32 [0.23-0.40] mm Hg/mL versus 0.28 [0.19-0.44] mm Hg/mL; P=0.7). In addition, mean pulmonary artery pressure-cardiac output and end systolic elastance-arterial elastance slopes remained unchanged after PEA. Conclusions The exertional RV stroke volume response improves significantly after PEA for chronic thromboembolic pulmonary hypertension despite a persistently abnormal afterload and absence of an RV contractile reserve. This may suggest that at mildly elevated pulmonary pressures, stroke volume is less dependent on RV contractility and afterload and is primarily determined by venous return and conduit function.

Pulmonary endarterectomy and balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension: Comparison of changes in hemodynamics and functional capacity

The treatment of choice for chronic thromboembolic pulmonary hypertension (CTEPH) is pulmonary endarterectomy (PEA). Balloon pulmonary angioplasty (BPA) is an emerging option for inoperable patients. Comparisons of the hemodynamic and functional outcome between these treatments are scarce. In this single-center observational cohort study, we compared hemodynamics by right heart catheterization and peak oxygen consumption before and 5 months (±14 days) after either PEA or BPA. Comprehensive evaluation and selection for PEA or BPA was performed by an expert CTEPH team. Fourty-two and fourty consecutive patients were treated with PEA or BPA, respectively. Demographics were similar between groups. Both PEA and BPA significantly reduced mean pulmonary artery pressure (from 46 ± 11 mmHg at baseline to 28 ± 13 mmHg at follow-up; p < 0.001 and from 43 ± 12 mmHg to 31 ± 9 mmHg; p < 0.001) and pulmonary vascular resistance (from 686 ± 347 dyn s cm-5 at baseline to 281 ± 197 dyn s cm-5 at follow-up; p < 0.001 and from 544 ± 322 dyn s cm-5 to 338 ± 180 dyn s cm-5; p < 0.001), with significantly lower reductions for both parameters in the former group. However, cardiopulmonary exercise testing revealed no significant between group differences in exercise capacity. Diffusion capacity for carbon monoxide at baseline was the only follow-up predictor for peak VO2. In our study, PEA reduced pulmonary pressures more than BPA did, but similar improvements were observed for exercise capacity. Thus, while long term data after BPA is lacking, BPA treated CTEPH patients can expect physical gains in line with PEA.

EmPHasis-10 Health-Related Quality of Life and Exercise Capacity in Chronic Thromboembolic Pulmonary Hypertension After Balloon Angioplasty

Background

Whether pulmonary hemodynamic parameters and functional capacity are associated with quality of life in patients with chronic thromboembolic pulmonary hypertension remains unknown. This study aimed to evaluate disease‐specific quality of life using the emPHasis‐10 questionnaire and assess its determinants in patients with chronic thromboembolic pulmonary hypertension with normalized pulmonary hemodynamics.

Methods and Results

This cross‐sectional study included 187 health status assessments of 143 patients with chronic thromboembolic pulmonary hypertension (median age, 68 [58–75] years; men/women, 51/136; use of home oxygen therapy, 51 patients [27%]) after balloon pulmonary angioplasty with normalized mean pulmonary artery pressure <25 mm Hg at rest. Right heart catheterization was performed, followed by assessment of 6‐minute walk distance and the emPHasis‐10 questionnaire. The median pulmonary artery pressure and pulmonary vascular resistance were 18 (15–21) mm Hg and 2.2 (1.7–2.9) wood units, respectively. The median emPHasis‐10 score was 14 (8–24), whereas the median 6‐minute walk distance was 447 (385–517) m. Univariate linear regression analysis showed that the emPHasis‐10 score was associated with 6‐minute walk distance (β=−0.476 [95% CI −0.604, −0.348], P<0.001) and home oxygen therapy (β=0.214 [95% CI, 0.072, 0.356], P=0.003) but not with hemodynamic parameters. Multiple regression analysis revealed that a higher emPHasis‐10 score was associated with lower 6‐minute walk distance (β=−0.475 [95% CI, −0.631 to −0.319], P<0.001).

Conclusions

Health‐related quality of life was associated with exercise capacity and the use of home oxygen therapy, but not with hemodynamic parameters, in patients with chronic thromboembolic pulmonary hypertension and normalized hemodynamics after balloon pulmonary angioplasty. Improvements in exercise capacity may lead to further improvements in quality of life.

Cardiopulmonary exercise test: A 20-year (2002-2021) bibliometric analysis

Background

The clinical application value of cardiopulmonary exercise test (CPET) has increasingly attracted attention, and related research has been increasing yearly. However, there is no summary analysis of the existing CPET literature. This is the first bibliometric analysis of publications in the CPET.

Methods

CPET-related articles published between 2002 and 2021 were retrieved from the Web of Science Core Collection database. The search was limited to Articles and Reviews in English. CiteSpace software was used to conduct collaborative network analysis of countries/regions, institutions, authors, the co-occurrence of subject categories and keywords, and co-citation analysis of authors, journals, and references.

Results

A total of 4,426 publications were identified. During the study period, the number of published articles increased yearly. Developed countries from the Americas and Europe led the field. The University of Milan was the most prolific institution, with Ross Arena and Wasserman K being the most prolific and co-cited authors in the field, respectively. Cardiovascular System &amp; Cardiology and Respiratory System were the main areas involved. Moreover, heart failure, oxygen uptake, and prognostic value were the central themes.

Conclusions

CPET had attracted widespread attention, and the number of publications will increase substantially according to the current growth trends. In the future, CPET is expected to be further adopted in large-scale clinical studies as a means of assessing the functional ability of patients to verify the efficacy of related interventions. High-quality evidence-based medical CPET-related indicators is expected to be used in clinical diseases risk prediction.

Right ventricle remodeling in chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is an underdiagnosed, but potentially curable pulmonary vascular disease. The increased pulmonary vascular resistance in CTEPH is caused by unresolved proximal thrombus and secondary microvasculopathy in the pulmonary vasculature, leading to adaptive and maladaptive remodeling of the right ventricle (RV), eventual right heart failure, and death. Knowledge on the RV remodeling process in CTEPH is limited. The progression to RV failure in CTEPH is a markedly slower process. A detailed understanding of the pathophysiology and underlying mechanisms of RV remodeling may facilitate early diagnosis and the development of targeted therapy. While ultrasound, magnetic resonance imaging, right heart catheterization, and serum biomarkers have been used to assess cardiac function, the current treatment strategies reduce the afterload of the right heart, but are less effective in improving the maladaptive remodeling of the right heart. This review systematically summarizes the current knowledge on adaptive and maladaptive remodeling of the right heart in CTEPH from molecular mechanisms to clinical practice.

Non-invasive follow-up strategy after pulmonary endarterectomy for CTEPH

Background

The success of pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH) is usually evaluated by performing a right heart catheterisation (RHC). Here, we investigate whether residual pulmonary hypertension (PH) can be sufficiently excluded without the need for a RHC, by making use of early post-operative haemodynamics, or N-terminal pro-brain natriuretic peptide (NT-proBNP), cardiopulmonary exercise testing (CPET) and transthoracic echocardiography (TTE) 6 months after PEA.

Methods

In an observational analysis, residual PH after PEA measured by RHC was related to haemodynamic data from the post-operative intensive care unit time and data from a 6-month follow-up assessment including NT-proBNP, TTE and CPET. After dichotomisation and univariate analysis, sensitivity, specificity, positive predictive value, negative predictive value (NPV) and likelihood ratios were calculated.

Results

Thirty-six out of 92 included patients had residual PH 6 months after PEA (39%). Correlation between early post-operative and 6-month follow-up mean pulmonary artery pressure was moderate (Spearman rho 0.465, p<0.001). Early haemodynamics did not predict late success. NT-proBNP >300 ng·L⁻¹ had insufficient NPV (0.71) to exclude residual PH. Probability for PH on TTE had a moderate NPV (0.74) for residual PH. Peak oxygen consumption (V′_O2) <80% predicted had the highest sensitivity (0.85) and NPV (0.84) for residual PH.

Conclusions

CPET 6 months after PEA, and to a lesser extent TTE, can be used to exclude residual CTEPH, thereby safely reducing the number of patients needing to undergo re-RHC after PEA.

In approximately one-third to one-half of CTEPH patients, residual pulmonary hypertension after pulmonary endarterectomy can be excluded based on cardiopulmonary exercise testing or echocardiography, without the need for right heart catheterisationhttps://bit.ly/3pbj2Ge

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.

Exercise hyperventilation and pulmonary gas exchange in chronic thromboembolic pulmonary hypertension: Effects of balloon pulmonary angioplasty

BACKGROUND

Excessive ventilation (V̇E) and abnormal gas exchange during exercise are features of chronic thromboembolic pulmonary hypertension (CTEPH). In selected CTEPH patients, balloon pulmonary angioplasty (BPA) improves symptoms and exercise capacity. How BPA affects exercise hyperventilation and gas exchange is poorly understood.

METHODS

In this longitudinal observational study, symptom-limited cardiopulmonary exercise tests and carbon monoxide lung diffusion (DLCO) were performed before and after BPA (interval, mean (SD): 3.1 (2.4) months) in 36 CTEPH patients without significant cardiac and/or pulmonary comorbidities.

RESULTS

Peak work rate improved by 20% after BPA whilst V̇E at peak did not change despite improved ventilatory efficiency (lower V̇E with respect to CO₂ output [V̇CO₂]). At the highest identical work rate pre- and post-BPA (75 (30) watts), V̇E and alveolar-arterial oxygen gradient (P(Ai-a)O₂) decreased by 17% and 19% after BPA, respectively. The physiological dead space fraction of tidal volume (VD/VT), calculated from measurements of arterial and mixed expired CO₂, decreased by 20%. In the meantime, DLCO did not change. The best correlates of P(Ai-a)O₂ measured at peak exercise were physiological VD/VT before BPA and DLCO after BPA.

CONCLUSIONS

Ventilatory efficiency, physiological VD/VT, and pulmonary gas exchange improved after BPA. The fact that DLCO did not change suggests that the pulmonary capillary blood volume and probably the true alveolar dead space were unaffected by BPA. The correlation between DLCO measured before BPA and P(Ai-a)O₂ measured after BPA suggests that DLCO may provide an easily accessible marker to predict the response to BPA in terms of pulmonary gas exchange.

Experiences with pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension at multiple centers in Taiwan

BACKGROUND

Of the types of pulmonary hypertension, chronic thromboembolic pulmonary hypertension (CTEPH) may be cured through pulmonary endarterectomy (PEA). In this study, we investigated patient experiences with PEA for CTEPH treatment in Taiwan.

METHODS

We retrospectively reviewed the records of patients who underwent PEA in two medical centers between January 2005 and December 2019. We measured the following outcomes: in-hospital complications, improvements in cardiac function and exercise capacity, survival using Kaplan-Meier analysis after PEA.

RESULTS

Twenty-seven patients (female: 17) with a mean age of 52.6 years underwent PEA. Pre-operatively, most patients were New York Heart Association functional class (NYHA FC) III (n = 19) and IV (n = 7). The mean periods from the onset of symptoms to diagnosis and from diagnosis to operation were 22.6 and 22.3 months, respectively. After PEA, mean intubation time, and length of intensive care unit and hospital stay were 9, 11, and 20 days, respectively. Most patients' NYHA FCs improved to I (n = 15) and II (n = 10). The mean 6-min walk test (6MWT) result improved by 60.5%. The in-hospital mortality, mean follow-up period, and 5- and 10-year overall survival rates were 3.7%, 77.0 months, 96.3%, and 84.3%, respectively. Furthermore, 5- and 10-year disease-specific survival rates were both 96.3%.

CONCLUSION

When pre-operative and post-operative statuses were compared, we found a significant improvement in NYHA FC and 6MWT distance. Our study also found a lower in-hospital mortality rate compared to other published studies, except compared to the newer data provided by the University of California, San Diego group.