Use of supplemental oxygen in patients with pulmonary arterial hypertension in REVEAL

Pulmonary rehabilitation in lung transplant candidates with pulmonary arterial hypertension

BACKGROUND

Pulmonary rehabilitation (PR) guidelines support the efficacy and safety of supervised exercise training in mild-moderate pulmonary arterial hypertension (PAH). However, the exercise training response and safety of PR in PAH lung transplant (LTx) candidates has not been described.

OBJECTIVES

(1) characterize the clinical characteristics and illness trajectory of adult patients with severe PAH listed for LTx and participating in PR; (2) evaluate the change in exercise capacity, aerobic and resistance training volumes; (3) assess PR safety.

METHODS

Single-centre retrospective cohort study of PAH LTx candidates listed January 2014-December 2018 attending a supervised, facility-based outpatient program three times per week. Functional capacity was evaluated using 6-min walk distance (6MWD). Aerobic and muscle training volumes were evaluated with paired comparisons.

RESULTS

40 PAH LTx candidates (age 50 ± 12 years, 73% females, mean pulmonary artery pressure 53 ± 16 mmHg) were included. The median listing duration was 91 [IQR 43-232] days. Sixteen patients (40%) had ≥1 admission pre-transplant. Nine patients (56%) were discharged home and resumed outpatient PR. Baseline 6MWD was 330 ± 119 metres (n = 40) with the final 6MWD pre-LTx increasing by 18 metres 95% CI (-18 to 56), p-value = 0.31, n = 25) over a median duration of 225 [IQR 70-311] days. Modest gains were observed in aerobic and resistance training volumes in PR with no adverse safety events.

CONCLUSION

Despite progressive and severe disease in PAH LTx candidates, patients safely participated in PR and maintained exercise capacity. Given frequent admissions, physiotherapy during hospitalization should focus on preserving functional capacity and facilitating re-integration into outpatient PR post-discharge.

Effects of acetazolamide on sleep disordered breathing in pulmonary vascular disease: a randomised controlled trial

Background

Patients with pulmonary vascular disease (PVD) often suffer from nocturnal hypoxaemia, but also from sleep apnoea. Short-term use of acetazolamide increases ventilation due to metabolic acidosis and also reduces loop gain. We investigated whether prolonged use of acetazolamide improves sleep disordered breathing in PVD.

Methods

In a randomised controlled crossover trial, patients with PVD were randomly assigned to acetazolamide 250 mg and placebo twice daily for 5 weeks. Patients underwent respiratory polygraphy at baseline and at the end of each intervention phase. Outcomes of interest were the effect of acetazolamide on mean nocturnal oxygen saturation (S pO2 ), time with oxygen saturation <90% (t <90), apnoea-hypopnoea index (AHI) and sleep apnoea severity.

Results

In 20 patients with PVD (55% women, nine with pulmonary arterial hypertension, 11 with distal chronic thromboembolic pulmonary hypertension; mean±sd nocturnal S pO2 88.8±3.5%, obstructive AHI 12.6±12.3 events·h-1), 5 weeks of acetazolamide resulted in a significant improvement in nocturnal oxygenation compared to placebo (mean nocturnal S pO2 +2.3% (95% CI 1.3-3.3%); p<0.001 and t <90 -18.8% (95% CI -29.6- -8.0%); p=0.001). Acetazolamide increased the proportion of patients with mean nocturnal S pO2 ≥90% from 45% to 85%. The percentage of patients with AHI >5 events·h-1 was reduced from 75% to 60% and with AHI >15 events·h-1 from 30% to 15%. Two patients discontinued the study because of mild side-effects.

Conclusions

Acetazolamide given for 5 weeks reduces nocturnal hypoxaemia in PVD to a clinically relevant level and reduces the proportion of patients with obstructive sleep apnoea.

Epidemiology of supplemental oxygen in patients with pulmonary hypertension

BACKGROUND AND OBJECTIVE

Patients with pulmonary hypertension (PH) may present with hypoxaemia at rest or during daily activities. There is no epidemiological data on the prescription of long-term oxygen therapy (LTOT) in patients with PH. The study sought to analyse the prevalence and incidence of LTOT prescription among patients with pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH) in Spain and to determine predictors for this prescription.

METHODS

A retrospective analysis was performed from the Spanish Registry of Pulmonary Arterial Hypertension (REHAP). Collected data included demographics and anthropometric measurements, functional class (FC), arterial blood gases, pulmonary function tests, haemodynamic measurements, six-minute walking distance (6MWD) and LTOT prescription. In addition, we assessed the prevalence and incidence of LTOT prescription by PH group and subtype and potential predictors for LTOT initiation in the first 5 years after diagnosis.

RESULTS

We analysed 4533 patients (69.9% PAH and 30.1% CTEPH), mostly female (64.5%), with a mean age of 53.0 ± 18.3 years. The prevalence of LTOT was 19.3% for all patients. The incidence of LTOT prescriptions decreased from 5.6% to 1.6% between 2010 and 2019, respectively. Predictors for LTOT prescription, excluding those that represent the indication for oxygen therapy were: FC (HR: 1.813), 6MWD (HR: 1.002), mean pulmonary arterial pressure (mPAP) (HR: 1.014), cardiac index (CI) (HR: 1.253), pulmonary vascular resistance (PVR) (HR: 1.023) and diffusing capacity of carbon monoxide (DLCO) (HR: 1.294).

CONCLUSION

The prevalence of LTOT in PAH and CTEPH patients is close to 20%. FC, 6MWD, mPAP, CI, PVR and DLCO were predictors for LTOT prescription.

Obstructive Sleep Apnea, Obesity Hypoventilation Syndrome, and Pulmonary Hypertension: A State-of-the-Art Review

The pathophysiological interplay between sleep-disordered breathing (SDB) and pulmonary hypertension (PH) is complex and can involve a variety of mechanisms by which SDB can worsen PH. These mechanistic pathways include wide swings in intrathoracic pressure while breathing against an occluded upper airway, intermittent and/or sustained hypoxemia, acute and/or chronic hypercapnia, and obesity. In this review, we discuss how the downstream consequences of SDB can adversely impact PH, the challenges in accurately diagnosing and classifying PH in the severely obese, and review the limited literature assessing the effect of treating obesity, obstructive sleep apnea, and obesity hypoventilation syndrome on PH.

Prognostic analysis of pulmonary hypertension with lung parenchymal lesion: Comparison of mortality with and without connective tissue disease

BACKGROUND

The prognosis of pulmonary hypertension (PH) associated with connective tissue diseases related to interstitial pneumonia (CTD-IP PH) is relatively good among patients with PH and lung disease. However, the impact of pulmonary vasodilator treatment on the prognosis of CTD-IP PH compared with that of PH-induced chronic lung disease (group-3 PH) remains unclear.

METHODS

From 2012 to 2022, 50 patients with lung parenchymal lesions diagnosed with PH (mean pulmonary arterial pressure >20 mmHg) at Juntendo University Hospital were divided into two groups: CTD-IP PH (30 patients) and group 3-PH (20 patients). The impact of pulmonary vasodilator treatment and the use of long-term oxygen therapy (LTOT) on the prognosis of each group was examined retrospectively.

RESULTS

The prognosis of CTD-IP PH was significantly better compared to group-3 PH. While the treatment with pulmonary vasodilators did not affect the prognosis in group 3-PH, the prognosis of the patients treated with vasodilators in the CTD-IP PH group was significantly better than that of the non-treated patients. Treatment with multi-pulmonary vasodilators did not affect the prognosis in CTD-IP PH. Although the prognosis for the patients with LTOT was poor in all registered patients in the present study, treatment with pulmonary vasodilators improved the prognosis even under the use of LTOT in CTD-IP PH (P = 0.002). In a multivariate analysis of the CTD-IP PH group, pulmonary vasodilator treatment was an independent factor for better prognosis.

CONCLUSION

Treatment with a pulmonary vasodilator for CTD-IP PH may improve the prognosis, even in patients requiring LTOT.

Lung Transplantation for Pulmonary Arterial Hypertension

TOPIC IMPORTANCE

Even though patients with pulmonary arterial hypertension have multiple therapeutic options, the disease can be refractory despite appropriate management. In patients with end-stage pulmonary arterial hypertension, lung transplantation has the potential both to extend survival and improve health-related quality of life. Pulmonary arterial hypertension is the only major diagnostic indication for transplantation that is not a parenchymal pulmonary process, and thus the care of these patients is unique.

REVIEW FINDINGS

This review focuses on the complexities of lung transplantation for patients with pulmonary arterial hypertension, presents the updated referral and listing criteria, and discusses the inequities in the organ allocation process that impact this disease group and the strategies to optimize outcomes for patients with pulmonary arterial hypertension who require lung transplantation.

SUMMARY

Lung transplantation is an effective and lifesaving therapy for patients with end-stage lung disease. Sadly, patients with pulmonary arterial hypertension face many challenges as it relates to transplantation including higher perioperative risks, inequities in the allocation system, and less favorable long-term outcomes. This review covers the complexities of transplantation in patients with pulmonary vascular disease.

Pulmonary Hypertension in Interstitial Lung Disease: Updates in Disease, Diagnosis, and Therapeutics

Pulmonary hypertension is a debilitating condition that frequently develops in the setting of interstitial lung disease, likely related to chronic alveolar hypoxemia and pulmonary vascular remodeling. This disease process is likely to be identified more frequently by providers given recent advancements in definitions and diagnostic modalities, and provides practitioners with emerging opportunities to improve patient outcomes and quality of life. Despite years of data suggesting against the efficacy of pulmonary vasodilator therapy in patients with pulmonary hypertension due to interstitial lung disease, new data have emerged identifying promising advancements in therapeutics. The authors present to you a comprehensive review of pulmonary hypertension in interstitial lung disease, reviewing our current understanding of pathophysiology, updates in diagnostic approaches, and highlights of recent clinical trials which provide an effective approach for medical management.

Pulmonary Hypertension in Interstitial Lung Disease: Management Options to Move Beyond Supportive Care

Purpose of Review

This review delineates current diagnostic and management strategies for pulmonary hypertension due to interstitial lung disease (PH-ILD).

Recent Findings

The INCREASE trial, a phase III multicenter, randomized, placebo-controlled trial demonstrated both improved 6-min walk distance and decreased disease progression with inhaled treprostinil. This pivotal trial led to inhaled treprostinil becoming the first FDA approved medication for treatment of PH-ILD. The availability of this treatment has generated subsequent recommendations for the screening for PH in patients with ILD. As a result, it is becoming increasingly important for clinicians to gain awareness and familiarity with the evolving management options for PH-ILD.

Summary

The management of PH-ILD has its roots in goal-directed treatment of the underlying lung disease. However, recent medication advances and ongoing clinical studies are opening opportunities for more disease-specific treatment.

Oxygen Therapy in Pulmonary Vascular Disease: A Systematic Review, Meta-Analysis, and Comment

Main pulmonary vascular diseases (PVD) with precapillary pulmonary hypertension (PH) are pulmonary arterial and chronic thromboembolic PH. Guidelines recommend supplemental oxygen therapy (SOT) for severely hypoxemic patients with PH, but evidence is scarce. The authors performed a systematic review and where possible meta-analyses on the effects of SOT on hemodynamics and exercise performance in patients with PVD. In PVD, short-term SOT significantly improved mean pulmonary artery pressure and exercise performance. There is growing evidence on the benefit of long-term SOT for selected patients with PVD regarding exercise capacity and maybe even survival.

The Goldilocks Oxygen Principle: not too little and not too much

Nature has evolved creative ways to maintain oxygen homeostasis, but what happens when these adaptations are insufficient? Here we discuss biochemical failure points across the oxygen spectrum from 'too little' to 'too much' oxygen and their potential contributions to cardiovascular disease.

2022 Brazilian Thoracic Association recommendations for long-term home oxygen therapy

Some chronic respiratory diseases can cause hypoxemia and, in such cases, long-term home oxygen therapy (LTOT) is indicated as a treatment option primarily to improve patient quality of life and life expectancy. Home oxygen has been used for more than 70 years, and support for LTOT is based on two studies from the 1980s that demonstrated that oxygen use improves survival in patients with COPD. There is evidence that LTOT has other beneficial effects such as improved cognitive function, improved exercise capacity, and reduced hospitalizations. LTOT is indicated in other respiratory diseases that cause hypoxemia, on the basis of the same criteria as those used for COPD. There has been an increase in the use of LTOT, probably because of increased life expectancy and a higher prevalence of chronic respiratory diseases, as well as greater availability of LTOT in the health care system. The first Brazilian Thoracic Association consensus statement on LTOT was published in 2000. Twenty-two years later, we present this updated version. This document is a nonsystematic review of the literature, conducted by pulmonologists who evaluated scientific evidence and international guidelines on LTOT in the various diseases that cause hypoxemia and in specific situations (i.e., exercise, sleep, and air travel). These recommendations, produced with a view to clinical practice, contain several charts with information on indications for LTOT, oxygen sources, accessories, strategies for improved efficiency and effectiveness, and recommendations for the safe use of LTOT, as well as a LTOT prescribing model.

Hospital readmission in systemic sclerosis associated pulmonary hypertension: Results from the PHAROS registry

OBJECTIVE

To identify individual-level factors associated with hospital readmission among individuals with systemic sclerosis associated pulmonary hypertension (SSc-PH).

METHODS

Individuals enrolled in the Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma (PHAROS) registry contributed clinical data related to SSc-PH disease severity and hospital admissions. Readmission was defined as a subsequent hospitalization within 12 months of any hospital discharge. Characteristics were compared between individuals with and without readmissions using Fisher's exact test, Wilcoxon rank-sum test, or Kruskal Wallis test. Logistic regression was used to estimate associations between clinical predictors and likelihood of readmission.

RESULTS

Of 572 individuals with SSc-PH enrolled in PHAROS, 54% had ≥1 hospitalizations between 2005 and 2016. Among individuals ever-hospitalized, 34% had ≥1 readmission. Individuals with vs without readmissions had shorter median (IQR) time between index hospitalization date and next PHAROS visit (37 (3, 80) vs 81 (42, 136) days, p< 0.001). Index admissions related to PH or SSc (vs non-PH/SSc related) were associated with an increased odds of 12-month readmission (aOR 6.6 (95% CI 3.2, 13.6) and aOR 2.2 (95% CI 1.1, 4.5), respectively). Readmission was less likely among home oxygen users (vs non-users) (aOR 0.44; 95% CI 0.22, 0.89). Race, age, sex, disease duration, and disease subtype were not associated with readmission.

CONCLUSION

The strongest predictor for 12-month readmission was an index hospitalization reason related to PH. Home oxygen use was associated with lower odds of readmission. Future studies should determine whether testing for the need for home oxygen mediates the risk of readmission in SSc-PH.

The Role of Exercise Testing in Pulmonary Vascular Disease: Diagnosis and Management

Exercise intolerance is the dominant symptom of pulmonary hypertension (PH). The gold standard for the estimation of exercise capacity is a cycle ergometer incremental cardiopulmonary exercise test (CPET). The main clinical variables generated by a CPET are peak oxygen uptake (Vo2peak), ventilatory equivalents for carbon dioxide (VE/Vco₂), systolic blood pressure, oxygen (O2) pulse, and chronotropic responses. PH is associated with hyperventilation at rest and at exercise, and an increase in physiologic dead space. Maximal cardiac output depends on right ventricular function and critically determines a PH patient's exercise capacity. Dynamic arterial O2 desaturation can also depress the Vo2peak.

Sleep-Disordered Breathing and Nocturnal Hypoxemia in Precapillary Pulmonary Hypertension: Prevalence, Pathophysiological Determinants, and Clinical Consequences

BACKGROUND AND OBJECTIVE

The clinical relevance and interrelation of sleep-disordered breathing and nocturnal hypoxemia in patients with precapillary pulmonary hypertension (PH) is not fully understood.

METHODS

Seventy-one patients with PH (age 63 ± 15 years, 41% male) and 35 matched controls were enrolled. Patients with PH underwent clinical examination with assessment of sleep quality, daytime sleepiness, 6-minute walk distance (6MWD), overnight cardiorespiratory polygraphy, lung function, hypercapnic ventilatory response (HCVR; by rebreathing technique), amino-terminal pro-brain natriuretic peptide (NT-proBNP) levels, and cardiac MRI (n = 34).

RESULTS

Prevalence of obstructive sleep apnea (OSA) was 68% in patients with PH (34% mild, apnea-hypopnea index [AHI] ≥5 to <15/h; 34% moderate to severe, AHI ≥15/h) versus 5% in controls (p < 0.01). Only 1 patient with PH showed predominant central sleep apnea (CSA). Nocturnal hypoxemia (mean oxygen saturation [SpO2] <90%) was present in 48% of patients with PH, independent of the presence of OSA. There were no significant differences in mean nocturnal SpO2, self-reported sleep quality, 6MWD, HCVR, and lung and cardiac function between patients with moderate to severe OSA and those with mild or no OSA (all p > 0.05). Right ventricular (RV) end-diastolic (r = -0.39; p = 0.03) and end-systolic (r = -0.36; p = 0.04) volumes were inversely correlated with mean nocturnal SpO2 but not with measures of OSA severity or daytime clinical variables.

CONCLUSION

OSA, but not CSA, is highly prevalent in patients with PH, and OSA severity is not associated with nighttime SpO2, clinical and functional status. Nocturnal hypoxemia is a frequent finding and (in contrast to OSA) relates to structural RV remodeling in PH.

Outcomes and Risk Factors of Systolic Pulmonary Artery Pressure Progression in Patients with Systemic Rheumatic Diseases: Follow-up Results from a Korean Registry

Objectives

This study aims to investigate the outcomes and risk factors associated with the progression of systolic pulmonary artery pressure (sPAP) in patients with systemic rheumatic diseases.

Patients and methods

A total of 532 patients (73 males, 459 females; median age 49 years; interquartile range (IQR), 36 to 62 years) registered with the Registry of Pulmonary Hypertension Associated with Rheumatic Diseases were included. Mortality curves were constructed using the Kaplan- Meier method and comparisons were performed using the log-rank test. A paired t-test was performed to evaluate the patients with markedly elevated sPAP between baseline and follow-up.

Results

The average follow-up duration was 31 months (IQR, 9 to 60 months). Of the patients, 196 had follow-up echocardiographs at least one year later. We defined the sPAP over 60 mmHg as markedly elevated. Patients in the increased sPAP above 60 mmHg at follow-up and persistently markedly elevated sPAP were associated with worse outcomes in all-cause mortality and pulmonary arterial hypertension-related mortality (p<0.001). In patients with systemic sclerosis, the majority of patients remained static within their pressure group or rose progressively: the patients with markedly elevated sPAP at follow-up were higher than those at baseline (32% versus 15%, p<0.01). In patients with mixed connective tissue disease (MCTD) or rheumatoid arthritis (RA), the majority of patients remained static within their pressure group or gradually improved: the patients with markedly elevated sPAP at follow-up were lower than those at baseline (RA=14% versus 29%, MCTD=5% versus 16%, p<0.05).

Conclusion

Persistently high sPAP or increase of sPAP over 60 mmHg at follow-up was associated with increased mortality. There were some differences in the progression of sPAP according to the underlying rheumatic diseases.

Residence at moderately high altitude and its relationship with WHO Group 1 pulmonary arterial hypertension symptom severity and clinical characteristics: the Pulmonary Hypertension Association Registry

BACKGROUND

WHO Group 1 pulmonary arterial hypertension is a progressive and potentially fatal disease. Individuals living at higher altitude are exposed to lower barometric pressure and hypobaric hypoxemia. This may result in pulmonary vasoconstriction and contribute to disease progression. We sought to examine the relationship between living at moderately high altitude and pulmonary arterial hypertension characteristics.

METHODS

Forty-two US centers participating in the Pulmonary Hypertension Association Registry enrolled patients who met the definition of WHO Group 1 pulmonary arterial hypertension. We utilized baseline data and patient questionnaire responses. Patients were divided into two groups: moderately high altitude residence (home ≥4000 ft) and low altitude residence (home <4000 ft) based on zip-code. Clinical characteristics, hemodynamic data, patient demographics, and patient reported quality of life metrics were compared.

RESULTS

Controlling for potential confounders (age, sex at birth, body mass index, supplemental oxygen use, race, 100-day cigarette use, alcohol use, and pulmonary arterial hypertension medication use), subjects residing at moderately high altitude had a 6-min walk distance 32 m greater than those at low altitude, despite having a pulmonary vascular resistance that was 2.2 Wood units higher. Additionally, those residing at moderately high altitude had 3.7 times greater odds of using supplemental oxygen.

CONCLUSION

Patients with pulmonary arterial hypertension who live at moderately high altitude have a higher pulmonary vascular resistance and are more likely to need supplemental oxygen. Despite these findings, moderately high altitude Pulmonary Hypertension Association Registry patients have better functional tolerance as measured by 6-min walk distance. It is possible that a "high-altitude phenotype" of pulmonary arterial hypertension may exist. These findings warrant further study.

Is Structured Exercise Performed with Supplemental Oxygen a Promising Method of Personalized Medicine in the Therapy of Chronic Diseases?

Aim: This systematic review aimed to explore the literature to identify in which types of chronic diseases exercise with supplemental oxygen has previously been utilized and whether this type of personalized therapy leads to superior effects in physical fitness and well-being. Methods: Databases (PubMed/MEDLINE, CINHAL, EMBASE, Web of knowledge and Cochrane Library) were searched in accordance with PRISMA. Eligibility criteria included adult patients diagnosed with any type of chronic diseases engaging in supervised exercise training with supplemental oxygen compared to normoxia. A random-effects model was used to pool effect sizes by standardized mean differences (SMD). Results: Out of the identified 4038 studies, 12 articles were eligible. Eleven studies were conducted in chronic obstructive pulmonary disease (COPD), while one study included coronary artery disease (CAD) patients. No statistical differences were observed for markers of physical fitness and patient-reported outcomes on well-being between the two training conditions (SMD −0.10; 95% CI −0.27, 0.08; p = 0.26). Conclusions: We found that chronic exercise with supplemental oxygen has mainly been utilized for COPD patients. Moreover, no superior long-term adaptations on physical fitness, functional capacity or patient-reported well-being were found, questioning the role of this method as a personalized medicine approach. Prospero registration: CRD42018104649.

ACVIM consensus statement guidelines for the diagnosis, classification, treatment, and monitoring of pulmonary hypertension in dogs

Pulmonary hypertension (PH), defined by increased pressure within the pulmonary vasculature, is a hemodynamic and pathophysiologic state present in a wide variety of cardiovascular, respiratory, and systemic diseases. The purpose of this consensus statement is to provide a multidisciplinary approach to guidelines for the diagnosis, classification, treatment, and monitoring of PH in dogs. Comprehensive evaluation including consideration of signalment, clinical signs, echocardiographic parameters, and results of other diagnostic tests supports the diagnosis of PH and allows identification of associated underlying conditions. Dogs with PH can be classified into the following 6 groups: group 1, pulmonary arterial hypertension; group 2, left heart disease; group 3, respiratory disease/hypoxia; group 4, pulmonary emboli/pulmonary thrombi/pulmonary thromboemboli; group 5, parasitic disease (Dirofilaria and Angiostrongylus); and group 6, disorders that are multifactorial or with unclear mechanisms. The approach to treatment of PH focuses on strategies to decrease the risk of progression, complications, or both, recommendations to target underlying diseases or factors contributing to PH, and PH‐specific treatments. Dogs with PH should be monitored for improvement, static condition, or progression, and any identified underlying disorder should be addressed and monitored simultaneously.