The 6MWT as a prognostic tool in pulmonary arterial hypertension: results from the COMPERA registry

Effect of internet-based pulmonary rehabilitation on physical capacity and health-related life quality in patients with chronic obstructive pulmonary disease-a systematic review and meta-analysis

PURPOSE

Pulmonary rehabilitation (PR) is now recognized as the most effective treatments for individuals with chronic obstructive pulmonary disease (COPD), internet-based PR arises a promising method. The aim of this study was to conduct a systematic review and meta-analysis for assessing the effect of internet-based PR programs on physical capacity and health-related quality of life in patients with COPD.

MATERIALS AND METHODS

Randomized controlled trials were identified through systematically searches in PubMed, EMBASE, web of science, CENTRAL, Cochrane Library, and Google Scholar databases.

RESULTS

Twelve studies (1433 patients) were included. For physical capacity, there was no significant difference between groups was found according to the 6-min walk test (6MWT) (MD10.42, 95% CI -2.92 to 23.77, p = 0.13, I2 = 0%). For the health-related quality of life, no significant difference between groups was found regarding the St George's Respiratory Questionnaire (SGRQ) (MD -0.64, 95% CI -3.52 to 2.23, p = 0.66), COPD assessment test (CAT)(MD -0.34, 95% CI -1.62 to 0.94, p = 0.60), modified Medical Research Council scale (mMRC)(MD 0.17, 95% CI -0.06 to 0.39, p = 0.15) and Chronic Respiratory Questionnaire (CRQ)(MD 1.32 95% CI -5.88 to 8.53, p = 0.72).

CONCLUSIONS

This study has established the potential for delivery of PR via the internet in demonstrating non-inferiority of physical capacity and health-related quality of life (HRQoL) compared with conventional PR.IMPLICATIONS FOR REHABILITATIONLong-term rehabilitation training for patients with chronic obstructive pulmonary disease needs a more convenient and feasible way.In this study, internet-based rehabilitation showed similar effects as conventional rehabilitation on physical activity and health-related quality of life.Internet-based rehabilitation strategies would be helpful for this population.All internet-based rehabilitation strategies should be simple and sustainable.

Effects of virtual reality-based pulmonary rehabilitation in patients with chronic obstructive pulmonary disease: A meta-analysis

BACKGROUND

Virtual reality (VR)-based pulmonary rehabilitation has been used in the management of chronic obstructive pulmonary disease (COPD). The efficacy of VR-based pulmonary rehabilitation for improving lung function in patients with COPD is controversial. Therefore, the aim of this meta-analysis was to evaluate the efficacy of VR combined with pulmonary rehabilitation for lung function in patients with COPD.

METHODS

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The search was performed in the Cochrane Library, EMBASE, Web of Science, PubMed, and China National Knowledge Infrastructure databases from inception to February 1, 2023. All included studies were randomized controlled trials that assessed VR combined with pulmonary rehabilitation for COPD patients. The effect size was calculated with standardized mean difference (SMD) and its 95% confidence interval (CI). The Cochrane Collaboration tool was used to assess the risk of bias. Publication bias was assessed by Egger test.

RESULTS

A total of 11 studies met the inclusion criteria and were included in this study. The combined effect size showed that VR combined with pulmonary rehabilitation was more effective than pulmonary rehabilitation alone at improving forced expiratory volume in 1 second% (SMD: 0.51; 95% CI 0.19,0.82; P = .002), forced expiratory volume in 1 second/forced vital capacity (SMD: 0.71; 95% CI 0.49,0.93; P < .001), dyspnea (SMD: -0.44; 95% CI -0.66, -0.22; P < .001), and 6-minute walking test (SMD: 059; 95% CI 0.39, 0.79; P < .001). In addition, the VR combined with pulmonary rehabilitation improved depression (SMD: -0.34; 95% CI -0.05, -0.03; P = .033) and anxiety mood (SMD: -0.57; 95% CI -1.11, -0.04; P = .036) compared with the pulmonary rehabilitation group.

CONCLUSION

This meta-analysis indicated that VR regimens could be used to enhance the therapeutic effect of pulmonary rehabilitation in patients with COPD. However, as a rapidly evolving field, more well-designed randomized controlled trials are needed to determine the impact of VR-based pulmonary rehabilitation on COPD patients.

Pulmonary rehabilitation in sarcoidosis: A systematic review and meta-analysis

BACKGROUND

Exercise intolerance, muscle weakness, dyspnoea, and fatigue are frequent complications in symptomatic sarcoidosis patients. Pulmonary rehabilitation improves exercise capacity, symptoms, and quality of life in patients with chronic respiratory diseases. Our objective was to systematically determine the effects of pulmonary rehabilitation in patients with sarcoidosis.

METHODS

A systematic review was conducted in seven databases. Studies that applied pulmonary rehabilitation in patients with sarcoidosis were reviewed. Two independent reviewers analysed the studies, extracted the data and assessed the quality of evidence.

RESULTS

Of the 406 reports returned by the initial search, five articles reporting on 184 patients were included in the data synthesis. Two studies included multi-component exercise, one inspiratory muscle training, one a physical activity incentivisation programme, and one a telerehabilitation program. In the intervention group (IG), we found significant improvement in exercise capacity (SMD 1.65, 95%CI 0.45, 2.86 points, p = 0.006). If we only analyse the studies that performed the 6-min walking test, the IG walked 40.3 (CI95% 20.3, 60.2) m higher than the control group (CG) (p < 0.001). Additionally, dyspnoea score was reduced (MD -0.42 95%CI -0.75, -0.10, p = 0.002). However, fatigue, quality of life and pulmonary function did not show any change.

CONCLUSION

Pulmonary rehabilitation could improve exercise capacity and dyspnoea perception in patients with sarcoidosis.

Time to clinical improvement: an appropriate surrogate endpoint for pulmonary arterial hypertension medication trials

Background

Many retrospective studies suggest that risk improvement may be a suitable efficacy surrogate endpoint for pulmonary arterial hypertension (PAH) medication trials. This prospective multicenter study assessed the efficacy of domestic ambrisentan in Chinese PAH patients and observed risk improvement and time to clinical improvement (TTCI) under ambrisentan treatment.

Methods

Eligible patients with PAH were enrolled for a 24-week treatment with ambrisentan. The primary efficacy endpoint was 6-min walk distance (Δ6MWD). The exploratory endpoints were risk improvement and TTCI, defined as the time from initiation of treatment to the first occurrence of risk improvement.

Results

A total of 83 subjects were enrolled. After ambrisentan treatment, Δ6MWD was significantly increased at week 12 (42.2 m, P < 0.0001) and week 24 (53.4 m, P < 0.0001). Within 24 weeks, risk improvement was observed in 53 (64.6%) subjects (P < 0.0001), which is higher than WHO-FC (30.5%) and TAPSE/PASP (32.9%). Kaplan-Meier analysis of TTCI showed a median improvement time of 131 days and a cumulative improvement rate of 75.1%. Also, TTCI is consistent across different baseline risk status populations (log-rank P = 0.51). The naive group had more risk improvement (P = 0.043) and shorter TTCI (log-rank P = 0.008) than the add-on group, while Δ6MWD did not show significant differences between the two groups.

Conclusions

Domestic ambrisentan significantly improved the exercise capacity and risk status of Chinese PAH patients. TTCI has a relatively high positive event rate within 24-week treatment duration. Compared to Δ6MWD, TTCI is not affected by baseline risk status. Additionally, TTCI could identify better improvements in patients, which Δ6MWD does not detect. TTCI is an appropriate composite surrogate endpoint for PAH medication trials.

Clinical Trial Registration

NCT No. [ClinicalTrials.gov], identifier [NCT05437224].

Usefulness of the Duke Activity Status Index to Assess Exercise Capacity and Predict Risk Stratification in Patients with Pulmonary Arterial Hypertension

Exercise capacity is an important component of risk assessment for pulmonary arterial hypertension (PAH). We investigated the association of the Duke Activity Status Index (DASI) with peak oxygen consumption (peakVO₂) and explored whether the DASI can discriminate the high-risk individuals in patients with PAH, according to peakVO₂ < 11 mL/min/kg. A total of 89 patients were evaluated using cardiopulmonary exercise testing (CPET) and DASI. The correlation between the DASI and peakVO₂ was measured by univariate analysis, and a receiver operating characteristic (ROC) curve analysis was conducted. The DASI was correlated with peakVO₂ in the univariate analysis. The ROC curve analysis revealed that the DASI had a discriminative value for identifying the individuals with a high risk in PAH patients (p < 0.001), with an area under ROC curve (AUC) of 0.79 (95% CI: 0.67-0.92). Similar results were observed in patients with PAH associated with congenital heart disease (CHD-PAH), (p = 0.001), with an AUC of 0.80 (95% CI: 0.658-0.947). Therefore, DASI reflects exercise capacity in patients with PAH and has good ability to discriminate patients with a low risk and a high risk, and it may be included in the risk assessment of PAH.

Individually tailored home-based physiotherapy program makes sustainable improvement in exercise capacity and daily physical activity in patients with pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a rare, chronic, progressive, and life-threatening cardiopulmonary disease. This study investigated the impact of an individually tailored 12 weeks home-based physiotherapy program in PAH patients, with the aim to evaluate change in exercise capacity and daily physical activity level.

METHODS

This was an analysis of secondary outcomes from a prospective, randomized, controlled intervention study. Twenty-one participants were recruited from the Latvian PH registry based on inclusion criteria and randomized in a training group (TG) and control group (CG). Both groups continued a medical target therapy, but for TG, the individually tailored home-based physiotherapy program was added including physical exercises, relaxation, self-control, education, and supervision with telehealth elements. Outcomes included a 6-min walk test (6MWT) (m) and daily physical activity based on accelerometry results assessed at baseline, after 12 weeks, and at follow-up 6 months after commencement of intervention.

RESULTS

6MWT distance significantly (p < 0.05) and clinically (>33 m) increased within TG after 12 weeks (51.8 m, 95% CI = 25.7-77.9 m, Cohen's d = 1.7) and at follow-up (75.5 m, 95% CI = 46.1-104.8 m, Cohen's d = 2.1). A significant difference in 6MWT results between the groups at 12 weeks and follow-up was approved. In TG, low-intensity activities significantly (p < 0.05) increased both after 12 weeks (Cohen's d = 1.6) and at follow-up (Cohen's d = 1.2), moderate-intensity activities significantly (p < 0.05) increased at follow-up (Cohen's d = 1.3), and no significant improvements were present in CG.

CONCLUSION

The individually tailored 12 weeks home-based physiotherapy program comprising comprehensive physical exercise training, relaxation, self-control skills training, and education, added to stable medical target therapy and supervised by physiotherapist through telehealth elements, is effective in improving exercise capacity and increasing daily time in low or moderate physical activities 6 months after commencement of the intervention in patients with PAH.

Dynamics of 6-Minute Walk Distance as a Predictor of Efficiency Specific Pulmonary Vasodilators

Pulmonary hypertension is a severe and often rapidly progressive disease with a fatal outcome. Approved specific therapy with five classes of drugs – prostanoids, endothelin receptor antagonists, phosphodiesterase-5 inhibitors, soluble guanylate cyclase stimulators and prostacyclin receptor agonists has significantly improved the prognosis of patients. An accessible and reproducible criterion of exercise tolerance – a distance walked in six-minute walk test (6MXD) – occupies one of the central places among the performance indicators (clinical, echocardiographic and hemodynamic) of specific pulmonary vasodilators. Reflecting the clinical severity of pulmonary hypertension and, according to some data, its long-term prognosis, the dynamics of 6MXD is an integral component of the combined primary endpoints of randomized controlled trials. In the CHEST-2019 recommendations, the dynamics of the 6MXD was used to standardize the randomized controlled trials. The 6MXD is indispensable for dynamic observation and decisionmaking on further treatment tactics 

Carbon Monoxide Diffusion Capacity as a Severity Marker in Pulmonary Hypertension

Carbon monoxide diffusion capacity (DLCO) is negatively associated with patient survival in idiopathic pulmonary hypertension (PH), but is not included in the risk stratification score proposed by the 2015 European guidelines. Since 2015, several new stratification scores based on a 3- or 4-severity scale have been explored. This retrospective cohort single-center study sought to investigate the association between DLCO and PH severity and survival. We included 85 treatment-naive patients with precapillary PH and DLCO measurement at diagnosis. DLCO status, based on lower and upper quartiles ranges, was added to a 3- and a 4-strata modified-risk assessment. DLCO was strongly associated with transplant-free survival (HR 0.939, 95% CI: 0.908–0.971, p < 0.001). In the intermediate and high-risk categories, DLCO was associated with transplant-free survival, irrespective of the risk category (HR 0.934, 95% CI: 0.880–0.980, p = 0.005). The correlation between modified-risk category and transplant-free survival was significant (HR 4.60, 95% CI: 1.294–16.352, p = 0.018). Based on the Akaike information criterion (AIC) levels, the 3- and 4-strata modified-risk stratification fits our results better than the conventional stratification. Low DLCO is associated with patient transplant-free survival, independently of the risk category. Inclusion of DLCO into a PH risk stratification score seems promising and needs further investigation.

Effects of WeChat platform-based health management on health and self-management effectiveness of patients with severe chronic heart failure

BACKGROUND

Epidemiological studies have found that the prevalence of chronic heart failure in China is 0.9%, the number of people affected is more than 4 million, and the 5-year survival rate is even lower than that of malignant tumors.

AIM

To determine the impact of WeChat platform-based health management on severe chronic heart failure patients’ health and self-management efficacy.

METHODS

A total of 120 patients suffering from chronic heart failure with cardiac function grade III-IV, under the classification of the New York Heart Association, were admitted to our hospital in May 2017. In January 2020, they were divided into two groups: A control group (with routine nursing intervention) and an observation group (with WeChat platform-based health management intervention). Changes in cardiac function, 6-min walking distance (6MWD), high-sensitivity cardiac troponin (hs-cTnT), and N-terminal pro B-type natriuretic peptide (NT-proBNP) were detected in both groups. The Self-Care Ability Scale (ESCA) score, Minnesota Living with Heart Failure Questionnaire score, and compliance score were used to evaluate self-management ability, quality of life, and compliance of the two groups. During a follow-up period of 12 mo, the occurrence of cardiovascular adverse events in both the groups was counted.

RESULTS

The left ventricular ejection fraction, stroke output, and 6MWD increased, and the hs-cTnT and NT-proBNP decreased in both the groups, as compared to those before the intervention. Further, cardiac function during the 6MWD, hs-cTnT, and NT-proBNP improved significantly in the observation group after intervention (P < 0.05). The scores of self-care responsibility, self-concept, self-care skills, and self-care health knowledge in the observation group were higher than those of the control group before intervention, and their ESCA scores were significantly improved after intervention (P < 0.05). The Minnesota heart failure quality of life (LiHFe) scores of physical restriction, disease symptoms, psychological emotion, social relations, and other items were decreased compared to those of the control group before intervention, and the LiHFe scores of the observation group were significantly improved compared to those of the control group (P < 0.05). With intervention, the compliance scores of rational diet, regular medication, healthy behavior, and timely reexamination were increased, thereby leading to the compliance scores of the observation group being significantly improved compared to those of the control group (P < 0.05). During the 12 mo follow-up, the incidence rates of acute myocardial infarction and cardiogenic rehospitalization in the observation group were lower than those of the control group, and the hospitalization time in the observation group was shorter than that of the control group, but there was no significant difference between the two groups (P > 0.05).

CONCLUSION

WeChat platform-based health management can improve the self-care ability and compliance of patients with severe chronic heart failure, improve the cardiac function and related indexes, reduce the occurrence of cardiovascular adverse events, and enable the avoidance of rehospitalization.

[Current Aspects of Definition and Diagnosis of Pulmonary Hypertension]

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

Portopulmonary Hypertension: From Bench to Bedside

Portopulmonary hypertension (PoPH) is defined as pulmonary arterial hypertension (PAH) associated with portal hypertension and is a subset of Group 1 pulmonary hypertension (PH). PoPH is a cause of significant morbidity and mortality in patients with portal hypertension with or without liver disease. Significant strides in elucidating the pathogenesis, effective screening algorithms, accurate diagnoses, and treatment options have been made in past 20 years. Survival of PoPH has remained poor compared to IPAH and other forms of PAH. Recently, the first randomized controlled trial was done in this patient population and showed promising results with PAH specific therapy. Despite positive effects on hemodynamics and functional outcomes, it is unclear whether PAH specific therapy has a beneficial effect on long term survival or transplant outcomes. In this review, we will discuss the epidemiology, pathophysiology, clinical and hemodynamic characteristics of PoPH. Additionally, this review will highlight the lacunae in our current management strategy, challenges faced and will provide direction to potentially useful futuristic management strategies.

Obesity, estrogens and adipose tissue dysfunction - implications for pulmonary arterial hypertension

Obesity is a prevalent global public health issue characterized by excess body fat. Adipose tissue is now recognized as an important endocrine organ releasing an abundance of bioactive adipokines including, but not limited to, leptin, adiponectin and resistin. Obesity is a common comorbidity amongst pulmonary arterial hypertension patients, with 30% to 40% reported as obese, independent of other comorbidities associated with pulmonary arterial hypertension (e.g. obstructive sleep apnoea). An 'obesity paradox' has been observed, where obesity has been associated with subclinical right ventricular dysfunction but paradoxically may confer a protective effect on right ventricular function once pulmonary hypertension develops. Obesity and pulmonary arterial hypertension share multiple pathophysiological mechanisms including inflammation, oxidative stress, elevated leptin (proinflammatory) and reduced adiponectin (anti-inflammatory). The female prevalence of pulmonary arterial hypertension has instigated the hypothesis that estrogens may play a causative role in its development. Adipose tissue, a major site for storage and metabolism of sex steroids, is the primary source of estrogens and circulating estrogens levels which are elevated in postmenopausal women and men with pulmonary arterial hypertension. This review discusses the functions of adipose tissue in both health and obesity and the links between obesity and pulmonary arterial hypertension. Shared pathophysiological mechanisms and the contribution of specific fat depots, metabolic and sex-dependent differences are discussed.

Prognostic value of six-minute walk distance at a South American pulmonary hypertension referral center

Six-minute walk distance (6MWD) assessment is recommended for pulmonary arterial hypertension multidimensional risk stratification. However, current 6MWD cut-off values were mainly derived from North American and European pulmonary arterial hypertension registries. Therefore, it is unknown if such cut-off values broadly apply to other geographical populations. In this study, we aimed to identify 6MWD cut-off values for Brazilian pulmonary arterial hypertension patients and to contrast our findings to current international Pulmonary Hypertension guidelines recommendations. One-hundred four consecutive pulmonary arterial hypertension patients were allocated in groups according to their 6MWD, considering 50 m as a clinically relevant 6MWD difference. Next, patients were categorized into different 6MWD ranges based on similar survival rates in each group: < 250 m, 250–400 m, and >400 m. The study outcome was all-cause mortality and transplantation according to the 6MWD range. Survival was truncated at five years. Median follow-up period was 4.35 years (0.48–5.00). Survival rates at 1, 2, 3, and 5 years were 96%, 89%, 81%, and 73%, respectively. Cox analyses adjusted for age, sex, and pulmonary arterial hypertension etiology showed that 6MWD < 250 m and >400 m were associated with higher and lower risk of all-cause mortality and transplantation. According to Harrell's c-statistic, the prognostic discrimination of the 6MWD cut-off value identified by the current study was 0.70 while international Pulmonary Hypertension guidelines 6MWD cut-offs value was 0.61. In conclusion, our findings suggest that 6MWD geographical variations should be considered when assessing risk stratification in pulmonary arterial hypertension.

The prognostic value of DLCO and pulmonary blood flow in patients with pulmonary hypertension

Background

Cardiac output is a prognostic marker in patients with pulmonary hypertension. Pulmonary blood flow as a surrogate for cardiac output can be measured non-invasively by inert gas rebreathing. We hypothesized that pulmonary blood flow can predict outcome in patients with pulmonary hypertension.

Methods

From January 2009 to January 2012, we measured pulmonary blood flow by inert gas rebreathing in outpatients with pulmonary hypertension. Patients with pulmonary hypertension confirmed by right heart catheterization and a valid inert gas rebreathing maneuver were followed until January 2016. The investigated outcome was all-cause mortality.

Results

We included 259 patients (mean age 65 ± 13 years, 53% female) with pulmonary hypertension and classified into groups 1 (n = 103), 2 (n = 26), 3 (n = 80), and 4 (n = 50) according to the current pulmonary hypertension classification system. The median time between pulmonary hypertension diagnosis and inert gas rebreathing was 9 (IQR 0; 36) months. During a median follow-up time of 51 (IQR 20; 68) months, 109 patients (42%) died. Parameters significantly associated with survival (in order of decreasing statistical strength) were diffusion capacity of the lung for carbon monoxide (DLCO), 6-minute walk distance (6-MWD), age, NTpro-BNP, WHO functional class, group 3 pulmonary hypertension, and tricuspid annular plane systolic excursion (TAPSE), while baseline hemodynamics and pulmonary blood flow were not. In multivariable Cox regression analysis, DLCO, age, 6-MWD, and TAPSE remained significant and independent predictors of the outcome. DLCO as the strongest parameter also significantly predicted survival in aetiological subgroups except for group 4.

Conclusions

DLCO is a strong and independent predictor for survival in patients with pulmonary hypertension of different aetiologies, while pulmonary blood flow measured by inert gas rebreathing is not.

The Role of Noninvasive Endpoints in Predicting Long-Term Outcomes in Pulmonary Arterial Hypertension

Background

Until recently, many clinical trials in patients with pulmonary arterial hypertension (PAH) evaluated exercise capacity with 6-minute walk distance (6MWD) as the primary endpoint. Common secondary endpoints include PAH functional class (FC), which assesses symptoms, and either brain natriuretic peptide (BNP) or the inactive N-terminal cleavage product of its prohormone (NT-proBNP), which assesses cardiac function.

Objective

Examine the relationships among 6MWD, FC, and BNP/NT-proBNP measured at baseline or follow-up with long-term outcomes in PAH studies.

Methods

Relevant literature from January 1990 to April 2018 were obtained by searching PubMed, Embase, and Cochrane. Articles in English reporting on associations between 6MWD, FC, or BNP/NT-proBNP and outcomes in PAH were identified. Each endpoint was evaluated individually. Prespecified inclusion and exclusion criteria were applied at level 1 (titles/abstracts) and level 2 (full-text review).

Results

The database search yielded 836 unique records; 65 full-text articles were reviewed. Twenty-five studies were eligible for inclusion. Findings supported the importance of measuring PAH noninvasive endpoints in predicting long-term outcomes. Patients with shorter or decreased 6MWD, poor (III/IV) or declining FC (e.g., from II to III), or elevated or increasing BNP/NT-proBNP had a higher risk of death and costly events (e.g., hospitalization, lung transplant). FC also predicted health care resource utilization and costs. Collectively, these endpoints establish risk groups that predict likelihood of complications from PAH or death.

Conclusion

Assessment of 6MWD, FC, and BNP/NT-proBNP provides low-cost, efficient, and noninvasive means of predicting long-term health and economic outcomes in patients with PAH.

Selexipag in the management of pulmonary arterial hypertension: an update

Selexipag is a compound that was designed to overcome the issues associated with oral administration of prostanoid compounds, beraprost and treprostinil in the treatment of pulmonary hypertension (PAH). As a selective IP agonist, it was designed to avoid the off-target prostanoid effects especially in the gastrointestinal system. To place this compound in context, this paper briefly reviews the efficacy, tolerability, and safety of subcutaneous, inhaled, and oral prostanoid preparations and comparesthemto selexipag. Selexipag is the first agent targeting a prostanoid receptor where a reduction in the primary efficacy morbidity/mortality composite end-point has been demonstrated. While safety outcomes favor selexipag over placebo, tolerability issues remain. Efficacy in terms of improvement in effort tolerance, hemodynamic and mortality benefit is less than seen with IV therapy. This is the first prostanoid demonstrated in a clinical trial to have added benefit in those on background double combination therapy and the first non IV prostanoid to demonstrate outcome benefit in the connective tissue disease (CTD) population in a randomized controlled trial.

A focus on riociguat in the treatment of pulmonary arterial hypertension

Current treatment of pulmonary arterial hypertension (PAH) targets three signalling pathways: the nitric oxide (NO) pathway, the endothelin pathway and the prostacyclin pathway. Riociguat is a soluble guanylate cyclase stimulator, acting via the NO pathway in a new way: unlike other common drugs targeting this pathway (eg tadalafil and sildenafil), riociguat acts independently of endogenous NO. This MiniReview focuses on PAH treatment with riociguat and on its advantages and disadvantages compared with other drugs targeting the NO pathway. In the PATENT-1 trial (NCT00810693), riociguat improved significantly the 6-minute walking distance in patients suffering from PAH, with a mean difference (MD) of 36 m compared with a placebo group. The results are comparable to those found for its competitors tadalafil (MD of 33 m) and sildenafil (MD of 50 m) in the PHIRST-1 trial (NCT00125918) and the SUPER-1 trial (NCT00644605). No obvious advantages were found regarding pharmacokinetic features and adverse events. In the RESPITE study (NCT02007629), patients with PAH with insufficient response to treatment with tadalafil or sildenafil were switched to riociguat. These results indicate that riociguat might be superior regarding efficacy to PDE-5 inhibitors in a patient group, where endogenous NO production might be insufficient. This finding was further examined in the REPLACE study (NCT02891850). Moreover, riociguat has shown promising anti-proliferative, anti-inflammatory and anti-fibrotic effects in animal models. Further investigations are needed to determine whether this applies also to human beings. Taken together, riociguat induces vasodilation of the pulmonary arteries and leads to an improvement in the ability to carry out physical activity.

Long-term effects of device-guided slow breathing in stable heart failure patients with reduced ejection fraction

Background

Slow breathing (SLOWB) alleviates symptoms of chronic heart failure (HF) but its long-term effects are unknown. We examined the acute and long-term impact of device-guided breathing on hemodynamics and prognostic parameters in HF patients with reduced ejection fraction (HFrEF).

Methods and results

Twenty-one patients with HFrEF (23.9 ± 5.8%, SD ± mean) on optimal medical therapy underwent blood pressure (BP), heart rate (HR), HR variability, 6-min walk test (6MWT), cardiopulmonary exercise testing (CPET), and echocardiography measurements before and 3 months after SLOWB home training (30 min daily). After 3 months, all patients were assigned to continue SLOWB (Group 1) or no-SLOWB (Group 2). All tests were repeated after 6 months. Acute SLOWB (18 ± 5 vs 8 ± 2 breaths/min, P < 0.001) had no influence on BP and HR but improved saturation (97 ± 2 vs 98 ± 2%, P = 0.01). Long-term SLOWB reduced office systolic BP (P < 0.001) but not central or ambulatory systolic BP. SLOWB reduced SDNN/RMSSD ratio (P < 0.05) after 3 months. One-way repeated measures of ANOVA revealed a significant increase in 6MWT and peak RER (respiratory exchange ratio) from baseline to 6-month follow-up in group 1 (P < 0.05) but not group 2 (P = 0.85 for 6MWT, P = 0.69 for RER). No significant changes in echocardiography were noted at follow-up. No HF worsening, rehospitalisation or death occurred in group 1 out to 6-month follow-up. Two hospitalizations for HF decompensation and two deaths ensued in group 2 between 3- and 6-month follow-up.

Conclusions

SLOWB training improves cardiorespiratory capacity and appears to slow the progression of HFrEF. Further long-term outcome studies are required to confirm the benefits of paced breathing in HFrEF.