Prostacyclin for pulmonary hypertension in adults

Subcutaneous hydration and medications infusions (effectiveness, safety, acceptability): A systematic review of systematic reviews

OBJECTIVE

To synthesize the current evidence for subcutaneous hydration and medication infusions from systematic reviews and to assess their methodological quality.

INTRODUCTION

Peripheral intravascular cannula/catheter insertion is a common invasive procedure for administering fluids and medications. Venous depletion is a growing concern for several patient populations. Subcutaneous access for the administration of isotonic solutions and medications is an alternative; however, vascular access assessment and planning guidelines rarely consider this route.

METHODS

Systematic review of systematic reviews (PROSPERO CRD42018046504). We searched 6 databases published in English language from 1990 to June 2020, identifying subcutaneous infusions an alternate route for fluids or medication. Methodological quality was evaluated using AMSTAR 2 criteria and data for mechanisms of infusion and outcomes related to effectiveness, safety, efficiency and acceptability extracted. The Johanna Briggs Institute's grades of recommendation informed the strength of recommendation.

RESULTS

The search yielded 1042 potential systematic reviews; 922 were excluded through abstract and duplicate screen. Of the remaining articles, 94 were excluded, and 26 were included. Overall, evidence is strong for recommending subcutaneous hydration infusions for older adults, weak for pediatric patients and inconclusive for palliative patients. There is strong evidence for 10 medications; weak evidence supporting 28 medications; however, there are eight medications with inconclusive evidence to make a recommendation and four medications not appropriate for subcutaneous delivery.

CONCLUSION

Subcutaneous access should be considered alongside intravenous therapy for hydration in older adults, and several medications. There are additional benefits in terms of ease of use and cost-effectiveness of this mode. Inclusion of subcutaneous access in clinical guidelines may promote uptake of this route to help preserve vessel health of vulnerable patients. Further high-quality research is needed to inform subcutaneous infusion therapy in a variety of populations (including pediatrics and palliative care) and medications and clarifying the mechanism of delivery.

Evidence synthesis in pulmonary arterial hypertension: a systematic review and critical appraisal

BACKGROUND

The clinical landscape of pulmonary arterial hypertension (PAH) has evolved in terms of disease definition and classification, trial designs, available therapies and treatment strategies as well as clinical guidelines. This study critically appraises published evidence synthesis studies, i.e. meta-analyses (MA) and network-meta-analyses (NMA), to better understand their quality, validity and discuss the impact of the findings from these studies on current decision-making in PAH.

METHODS

A systematic literature review to identify MA/NMA studies considering approved and available therapies for treatment of PAH was conducted. Embase, Medline and the Cochrane's Database of Systematic Reviews were searched from database inception to April 22, 2020, supplemented by searches in health technology assessment websites. The International Society for Pharmacoeconomics and Outcomes Research (ISPOR) checklist covering six domains (relevance, credibility, analysis, reporting quality and transparency, interpretation and conflict of interest) was selected for appraisal of the included MA/NMA studies.

RESULTS

Fifty-two full publications (36 MAs, 15 NMAs, and 1 MA/NMA) in PAH met the inclusion criteria. The majority of studies were of low quality, with none of the studies being scored as 'strong' across all checklist domains. Key limitations included the lack of a clearly defined, relevant decision problem, shortcomings in assessing and addressing between-study heterogeneity, and an incomplete or misleading interpretation of results.

CONCLUSIONS

This is the first critical appraisal of published MA/NMA studies in PAH, suggesting low quality and validity of published evidence synthesis studies in this therapeutic area. Besides the need for direct treatment comparisons assessed in long-term randomized controlled trials, future efforts in evidence synthesis in PAH should improve analysis quality and scrutiny in order to meaningfully address challenges arising from an evolving therapeutic landscape.

Prostacyclin for pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is characterised by pulmonary vascular changes, leads to elevated pulmonary artery pressures, dyspnoea, a reduction in exercise tolerance, right heart failure, and ultimately death.Prostacyclin analogue drugs mimic endogenous prostacyclin which leads to vasodilation, inhibition of platelet aggregation, and reversal of vascular remodelling. Prostacyclin's short half-life theoretically enhances selectivity for the pulmonary vascular bed by direct (via central venous catheter) administration. Initial continuous infusion prostacyclins were efficacious, but use of intravenous access increases the risk of adverse events. Newer and safer subcutaneous, oral and inhaled preparations are now available, though possibly less potent.Selexipag is an oral selective prostacyclin receptor (IP receptor) agonist that works similarly to prostacyclin, potentially more stable, with less complex administration and titration.

OBJECTIVES

To determine the efficacy and safety of prostacyclin, prostacyclin analogues or prostacyclin receptor agonists for PAH in adults and children.

SEARCH METHODS

We performed searches on CENTRAL, MEDLINE, and Embase up to 16 September 2018. We handsearched review articles, clinical trial registries, and reference lists of retrieved articles.

SELECTION CRITERIA

We included any randomised controlled trials (RCTs) which compared prostacyclin, prostacyclin analogues or prostacyclin receptor agonists to control (placebo, any other treatment or usual care) for at least six weeks.

DATA COLLECTION AND ANALYSIS

We used standard methods specified by Cochrane. Primary outcomes included change in World Health Organization (WHO) functional class, six-minute walk distance (6MWD), and mortality.

MAIN RESULTS

Seventeen trials with 3765 mostly adult participants were included; median trial duration was 12 weeks. Fifteen trials used prostacyclin analogues: intravenous (N = 4); subcutaneous (N = 1); oral (N = 5); inhaled (N = 5); two used oral prostacyclin receptor agonists. Three intravenous and two inhaled trials were open-label.Participants using prostacyclin had 2.39 times greater odds of improving by at least one WHO functional class (95% confidence interval (CI) 1.72 to 3.32; 24 per 100 (95% CI 18.5 to 30.4) with prostacyclin compared to 12 per 100 with control; 8 trials, 1066 participants; moderate-certainty evidence). Improvement occurred with intravenous (odds ratio (OR) 14.96, 95% CI 4.76 to 47.04), and inhaled (OR 2.94, 95% CI 1.53 to 5.66), but not with oral preparations. Participants using prostacyclin increased their 6MWD by 19.50 metres (95% CI 14.82 to 24.19; 13 trials, 2283 participants; low-certainty evidence), which was clinically significant with intravenous (mean difference (MD) 91.76 metres; 95% CI 58.97 to 124.55), but not with non-intravenous preparations (subcutaneous: MD 16.00 metres, 95% CI 7.38 to 24.62; oral: MD 14.76 metres, 95% CI 7.81 to 21.70; inhaled: MD 26.97 metres, 95% CI 17.21 to 36.73). Mortality was reduced in the intravenous (OR 0.29, 95% CI 0.12 to 0.69; risk of death 6 per 100 (95% CI 2.38 to 12.31) with prostacyclin compared to 17 per 100 with control; 4 trials, 255 participants), but not in the non-intravenous studies (OR 0.82, 95% CI 0.48 to 1.40; risk of death 21 per 1000 (95% CI 12.00 to 34.20) with prostacyclin compared to 25 per 1000 with control; moderate-certainty evidence; 12 trials, 2299 participants). We reduced the certainty of evidence due to few studies per subgroup and use of open-label trials.Prostacyclins improved cardiopulmonary haemodynamics (reduction in mean pulmonary artery pressure by 3.60 mmHg (95% CI -4.73 to -2.48); pulmonary vascular resistance by 2.81 WU (95% CI -3.80 to -1.82); right atrial pressure by 1.90 mmHg (95% CI -2.58 to -1.22), and increase in cardiac index by 0.31 L/min/m² (95% CI 0.23 to 0.38); low-certainty evidence), improved dyspnoea (low-certainty evidence, and improved quality of life (moderate-certainty evidence), when compared to control. When only subcutaneous/inhaled trials were included the effect was still significant, but the magnitude was smaller. There was no difference across oral trials.Adverse events were increased in all prostacyclin preparations, including vasodilation (OR 5.03, 95% CI 3.84 to 6.58), headache (OR 3.16, 95% CI 2.62 to 3.80), jaw pain (OR 5.25, 95% CI 3.96 to 6.98), diarrhoea (OR 2.81, 95% CI 2.29 to 3.46), nausea/vomiting (OR 2.39, 95% CI 1.98 to 2.88), myalgias (OR 2.75, 95% CI 1.65 to 4.58), upper respiratory tract events (OR 1.61, 95% CI 1.22 to 2.13), extremity pain (OR 3.36, 95% CI 2.32 to 4.85), and infusion site reactions (OR 14.41, 95% CI 9.16 to 22.66). In the intravenous trials, there was a 12%-25% risk of serious non-fatal events including sepsis, haemorrhage, pneumothorax and pulmonary embolism.Two trials (1199 participants) compared oral selexipag to placebo; no trials compared selexipag with prostacyclin. There was a small 12.62 metre improvement in 6MWD (95% CI 1.90 to 23.34; high-certainty evidence), and weak evidence for haemodynamics. The effect was uncertain for WHO functional class. The risk of death with selexipag was five per 100 compared to three per 100 with placebo, though the CI crossed zero so the true effect is uncertain (risk difference (RD) 0.02 (95% CI -0.00 to 0.04). There was less clinical worsening with selexipag (OR 0.47, 95% CI 0.37 to 0.60), though more side effects, including vasodilation (OR 2.67, 95% CI 1.72 to 4.17), headache (OR 3.91, 95% CI 3.07 to 4.98), jaw pain (OR 5.33, 95% CI 3.64 to 7.81), diarrhoea (OR 3.11, 95% CI 2.39 to 4.05), nausea/vomiting (OR 2.92, 95% CI 2.29 to 3.73), pain in the extremities (OR 2.44, 95% CI 1.69 to 3.52), and myalgias (OR 3.05, 95% CI 2.02 to 4.58).

AUTHORS' CONCLUSIONS

This review demonstrates clinical and statistical benefit for intravenous prostacyclin (compared to control) with improved functional class, 6MWD, mortality, symptoms scores, and cardiopulmonary haemodynamics, but at a cost of adverse events. This may be due to a true effect, or may be overestimated due to the inclusion of small, short or open-label studies. There was a statistical and small clinical benefit in function and haemodynamics for inhaled prostacyclin, but the effect is uncertain for mortality. The effect of oral prostacyclins are less certain. Selexipag demonstrated less clinical worsening without discernable impact on survival, increased adverse events; and the effect on other outcomes is less certain. Real-world registry data may provide further information about clinical effect.

Review: Hemodynamic Characteristics and Outcomes of Sickle Cell Disease Associated Pulmonary Hypertension

Pulmonary hypertension (PH) is a leading cause of morbidity and early mortality in adults with sickle cell disease (SCD). However, the prevalence, hemodynamic profile and prognosis of SCD-PH remain controversial and need frequent updates. Pulmonary hypertension determined by right heart catheterization (RHC) occurs in 6% to 10% of adults with SCD. Hemodynamically, SCD-PH may be pre-capillary or post-capillary in nature. The exact etiology is unknown and often multifactorial; hence a thorough diagnostic evaluation following established PH guidelines is essential to determine disease prevalence, etiology and outcomes. Data on the efficacy and safety of pulmonary arterial hypertension (PAH) therapy are limited in SCD; clinical trials in these patients are urgently needed. This review provides an overview of RHC-determined hemodynamic characteristics, current management modality and outcomes; we also highlight recent advances and unmet research needs in SCD-PH.

Comparison of Treatment Response in Idiopathic and Connective Tissue Disease-associated Pulmonary Arterial Hypertension

RATIONALE

Studies suggest that patients with connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH) have a poorer treatment response to therapies for PAH compared with patients with idiopathic PAH (IPAH), but individual randomized controlled trials (RCTs) have been underpowered to examine differences within these subgroups.

OBJECTIVES

To compare the effect of therapy for PAH in CTD-PAH versus IPAH.

METHODS

We obtained individual participant data from phase III placebo-controlled RCTs of therapies for PAH submitted to the U.S. Food and Drug Administration for drug approval. A treatment-by-diagnosis interaction term evaluated differences in treatment response between CTD-PAH and IPAH. Outcomes included change in 6-minute-walk distance (∆6MWD) from baseline to 12 weeks, clinical worsening, and all-cause mortality.

MEASUREMENTS AND MAIN RESULTS

The study sample included 827 participants with CTD-PAH and 1,935 with IPAH from 11 RCTs. Patients with CTD-PAH had less improvement in 6MWD when assigned to active treatment versus placebo compared with patients with IPAH (difference in treatment effect on ∆6MWD in CTD-PAH vs. IPAH, -17.3 m; 90% confidence interval, -31.3 to -3.3; P for interaction = 0.043). Treatment was less effective in reducing the occurrence of clinical worsening in CTD-PAH versus IPAH (P for interaction = 0.012), but there was no difference in the placebo-adjusted effect of treatment on mortality (P for interaction = 0.65).

CONCLUSIONS

Treatment for PAH was less effective in CTD-PAH compared with IPAH in terms of increasing 6MWD and preventing clinical worsening. The heterogeneity of treatment response supports the need for identifying therapies that are more effective for CTD-PAH.

Exercise capacity and cardiac hemodynamic response in female ApoE/LDLR(-/-) mice: a paradox of preserved V'O2max and exercise capacity despite coronary atherosclerosis

We assessed exercise performance, coronary blood flow and cardiac reserve of female ApoE/LDLR^−/− mice with advanced atherosclerosis compared with age-matched, wild-type C57BL6/J mice. Exercise capacity was assessed as whole body maximal oxygen consumption (V’O_2max), maximum running velocity (v_max) and maximum distance (DIST_max) during treadmill exercise. Cardiac systolic and diastolic function in basal conditions and in response to dobutamine (mimicking exercise-induced cardiac stress) were assessed by Magnetic Resonance Imaging (MRI) in vivo. Function of coronary circulation was assessed in isolated perfused hearts. In female ApoE/LDLR^−/− mice V’O_2max, v_max and DIST_max were not impaired as compared with C57BL6/J mice. Cardiac function at rest and systolic and diastolic cardiac reserve were also preserved in female ApoE/LDLR^−/− mice as evidenced by preserved fractional area change and similar fall in systolic and end diastolic area after dobutamine. Moreover, endothelium-dependent responses of coronary circulation induced by bradykinin (Bk) and acetylcholine (ACh) were preserved, while endothelium-independent responses induced by NO-donors were augmented in female ApoE/LDLR^−/− mice. Basal COX-2-dependent production of 6-keto-PGF_1α was increased. Concluding, we suggest that robust compensatory mechanisms in coronary circulation involving PGI₂- and NO-pathways may efficiently counterbalance coronary atherosclerosis-induced impairment in V’O_2max and exercise capacity.

An official American Thoracic Society clinical practice guideline: diagnosis, risk stratification, and management of pulmonary hypertension of sickle cell disease

BACKGROUND

In adults with sickle cell disease (SCD), an increased tricuspid regurgitant velocity (TRV) measured by Doppler echocardiography, an increased serum N-terminal pro-brain natriuretic peptide (NT-pro-BNP) level, and pulmonary hypertension (PH) diagnosed by right heart catheterization (RHC) are independent risk factors for mortality.

METHODS

A multidisciplinary committee was formed by clinician-investigators experienced in the management of patients with PH and/or SCD. Clinically important questions were posed, related evidence was appraised, and questions were answered with evidence-based recommendations. Target audiences include all clinicians who take care of patients with SCD.

RESULTS

Mortality risk stratification guides decision making. An increased risk for mortality is defined as a TRV equal to or greater than 2.5 m/second, an NT-pro-BNP level equal to or greater than 160 pg/ml, or RHC-confirmed PH. For patients identified as having increased mortality risk, we make a strong recommendation for hydroxyurea as first-line therapy and a weak recommendation for chronic transfusions as an alternative therapy. For all patients with SCD with elevated TRV alone or elevated NT-pro-BNP alone, and for patients with SCD with RHC-confirmed PH with elevated pulmonary artery wedge pressure and low pulmonary vascular resistance, we make a strong recommendation against PAH-specific therapy. However, for select patients with SCD with RHC-confirmed PH who have elevated pulmonary vascular resistance and normal pulmonary capillary wedge pressure, we make a weak recommendation for either prostacyclin agonist or endothelin receptor antagonist therapy and a strong recommendation against phosphodiesterase-5 inhibitor therapy.

CONCLUSIONS

Evidence-based recommendations for the management of patients with SCD with increased mortality risk are provided, but will require frequent reassessment and updating.

Endothelin receptor antagonists for pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension is a devastating disease, which leads to right heart failure and premature death. Recent evidence suggests that endothelin receptor antagonists may be promising drugs in the treatment of pulmonary arterial hypertension.

OBJECTIVES

To evaluate the efficacy of endothelin receptor antagonists in pulmonary arterial hypertension.

SEARCH METHODS

We searched CENTRAL (Cochrane Central Register of Controlled Trials), MEDLINE, EMBASE, and the reference section of retrieved articles. Searches are current as of January 2012.

SELECTION CRITERIA

We included randomised trials (RCTs) and quasi-randomised trials involving patients with pulmonary arterial hypertension.

DATA COLLECTION AND ANALYSIS

Five review authors independently selected studies, assessed study quality and extracted data.

MAIN RESULTS

We included 12 randomised controlled trials involving 1471 patients. All the trials were of relatively short duration (12 weeks to six months). After treatment, patients treated with endothelin receptor antagonists could walk on average 33.71 metres (95% confidence interval (CI) 24.90 to 42.52 metres) further than those treated with placebo in a six-minute walk test. Endothelin receptor antagonists improved more patients' World Health Organization/New York Heart Association (WHO/NYHA) functional class status than placebo (odds ratio (OR) 1.60; 95% CI 1.20 to 2.14), and reduced the odds of functional class deterioration compared with placebo (OR 0.26; 95% CI 0.16 to 0.42). There was a reduction in mortality that did not reach statistical significance on endothelin receptor antagonists (OR 0.57; 95% CI 0.26 to 1.24), and limited data suggest that endothelin receptor antagonists improve the Borg dyspnoea score and cardiopulmonary haemodynamics in symptomatic patients. Hepatic toxicity was not common, and endothelin receptor antagonists were well tolerated in this population. However, several cases of irreversible liver failure caused by sitaxsentan have been reported that led to license holder for sitaxsentan to withdraw the product from all markets worldwide.

AUTHORS' CONCLUSIONS

Endothelin receptor antagonists can increase exercise capacity, improve WHO/NYHA functional class, prevent WHO/NYHA functional class deterioration, reduce dyspnoea and improve cardiopulmonary haemodynamic variables in patients with pulmonary arterial hypertension with WHO/NYHA functional class II and III. However, there was only a trend towards endothelin receptor antagonists reducing mortality in patients with pulmonary arterial hypertension. Efficacy data are strongest in those with idiopathic pulmonary hypertension. The irreversible liver failure caused by sitaxsentan and its withdrawal from global markets emphasise the importance of hepatic monitoring in patients treated with endothelin receptor antagonists.

Intra-abdominal bleeding during treprostinil infusion in a patient with pulmonary arterial hypertension

Medical treatment of pulmonary arterial hypertension (PAH) is increasingly common. Prostacyclins were introduced in the early 90s, and treprostinil is one of the most frequently used drugs of this class today, owing to its long half-life and to the possibility to administer the molecule through several routes. Treprostinil is considered a safe drug and is associated with a significant improvement of exercise capacity, especially in patients with idiopathic PAH (iPAH). Systemic sclerosis-associated PAH (sc-PAH) correlates to a worse prognosis compared with that of iPAH. Despite these considerations, safety data on treprostinil are still limited and mainly derived from randomised controlled trials and retrospective studies with relatively small and heterogeneous cohorts of patients with PAH. We report the occurrence of a severe intra-abdominal bleeding during treprostinil infusion in a patient with sc-PAH.

New approaches to the treatment of pulmonary hypertension: from bench to bedside

Pulmonary hypertension (PH) is a severe, life-threatening disease for which there are no effective curative therapies. A diverse group of agents such as prostacyclins, endothelin antagonists, phosphodiesterase inhibitors, calcium channel blockers, diuretics, inotropic agents, and anticoagulants are used to treat PH; however, none of these agents have a marked effect upon survival. Among the new agents that promise treatment of PH are rho-kinase inhibitors and soluble guanylate cyclase stimulators. Although these new classes of agents have beneficial effects in experimental animal models and clinical studies, they are not selective in their actions on the pulmonary vascular bed. This manuscript reviews the actions of rho-kinase inhibitors and soluble guanylate cyclase stimulators on the pulmonary vascular bed. It is our hypothesis that these new agents may be more effective than current therapies in the treatment of PH. Moreover, new methods in the delivery of these agents to the lung need to be developed so that their main effects will be exerted in the pulmonary vascular bed and their systemic effects can be minimized or avoided.

An integrative review of systematic reviews related to the management of breathlessness in respiratory illnesses

BACKGROUND

Breathlessness is a debilitating and distressing symptom in a wide variety of diseases and still a difficult symptom to manage. An integrative review of systematic reviews of non-pharmacological and pharmacological interventions for breathlessness in non-malignant disease was undertaken to identify the current state of clinical understanding of the management of breathlessness and highlight promising interventions that merit further investigation.

METHODS

Systematic reviews were identified via electronic databases between July 2007 and September 2009. Reviews were included within the study if they reported research on adult participants using either a measure of breathlessness or some other measure of respiratory symptoms.

RESULTS

In total 219 systematic reviews were identified and 153 included within the final review, of these 59 addressed non-pharmacological interventions and 94 addressed pharmacological interventions. The reviews covered in excess of 2000 trials. The majority of systematic reviews were conducted on interventions for asthma and COPD, and mainly focussed upon a small number of pharmacological interventions such as corticosteroids and bronchodilators, including beta-agonists. In contrast, other conditions involving breathlessness have received little or no attention and studies continue to focus upon pharmacological approaches. Moreover, although there are a number of non-pharmacological studies that have shown some promise, particularly for COPD, their conclusions are limited by a lack of good quality evidence from RCTs, small sample sizes and limited replication.

CONCLUSIONS

More research should focus in the future on the management of breathlessness in respiratory diseases other than asthma and COPD. In addition, pharmacological treatments do not completely manage breathlessness and have an added burden of side effects. It is therefore important to focus more research on promising non-pharmacological interventions.

No effect of epoprostenol on right ventricular diameter in patients with acute pulmonary embolism: a randomized controlled trial

BACKGROUND

Right ventricular dilatation in the setting of acute pulmonary embolism is associated with an adverse prognosis. Treatment with a pulmonary vasodilator has never been studied systematically. We evaluated the effect of epoprostenol on right ventricular diameter and function in patients with acute pulmonary embolism and right ventricular dilatation.

METHODS

In a randomized, single-blind study, 14 patients with acute pulmonary embolism received epoprostenol or placebo infusion for 24 hours on top of conventional treatment. Effects on right ventricular end-diastolic diameter, systolic pulmonary artery pressure, right ventricle fractional area change and tricuspid annular plane systolic excursion were assessed by serial echocardiography. Furthermore Troponin T and NT-proBNP were measured serially.

RESULTS

Compared to placebo, epoprostenol was associated with a relative change from baseline in right ventricular end-diastolic diameter of +2% after 2.5 hours and -8% after 24 hours. Epoprostenol did not have a significant effect on systolic pulmonary artery pressure, right ventricular fractional area change and tricuspid annular plane systolic excursion, nor on biochemical parameters.

CONCLUSION

In patients with acute pulmonary embolism and right ventricular overload, treatment with epoprostenol did not improve right ventricular dilatation or any other measured variables of right ventricular overload.

TRIAL REGISTRATION

REGISTRATION

URL: NCT01014156Medical ethical committee: Medisch-ethische toetsingscommissie (METc) from the VUmc (free university medical centre).

Exercise training in patients with pulmonary arterial hypertension: a case report

PURPOSE

To describe the benefits of a feasible, outpatient exercise training program on exercise tolerance and health-related quality of life (HRQL) in individuals with pulmonary arterial hypertension (PAH).

METHODS

Case report on two subjects recruited from a tertiary care pulmonary hypertension clinic. Subject 1 was a 50-year-old male with idiopathic PAH. Subject 2 was a 54-year-old female with a 20+ year history of scleroderma and 6-year history of PAH. Both subjects underwent exercise training 3 times per week for 6 weeks using a cycle ergometer at workloads progressing from 50% to 80% of peak workload. Outcomes were assessed using cardiopulmonary exercise testing, six-minute walk test (6MWT), and HRQL using the Chronic Respiratory Disease Questionnaire (CRQ) and the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR).

RESULTS

Both subjects made substantial improvements in oxygen consumption and workload at anaerobic threshold (improvements of 3.8 and 4.2 mL.kg(-1).min,(-1) 26 and 18 W, respectively) and 6MWT distance (from 496 to 586m and 416 to 517m, respectively). Only Subject 1 made substantial improvements in peak oxygen consumption (from 16.0 to 18.3 mL.kg(-1).min(-1)and from 15.0 to 15.6 mL.kg(-1).min,(-1) respectively) and peak work rate (from 112 to 130W and 66 to 69W, respectively). Both subjects demonstrated improved HRQL. No adverse events were noted.

CONCLUSIONS

A short and practical exercise training program can improve measures of workload, aerobic capacity, and HRQL in individuals with PAH with no adverse effects shown in these two case studies.

Endothelin receptor antagonists for pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension is a devastating disease, which leads to right heart failure and premature death. Recent evidence suggests that endothelin receptor antagonists may be promising drugs in the treatment of pulmonary arterial hypertension.

OBJECTIVES

To evaluate the efficacy of endothelin receptor antagonists in pulmonary arterial hypertension.

SEARCH STRATEGY

We searched CENTRAL (Cochrane Central Register of Controlled Trials), MEDLINE, EMBASE, and the reference section of retrieved articles. Searches are current as of Februray 2008.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-randomised controlled trials involving patients with pulmonary arterial hypertension.

DATA COLLECTION AND ANALYSIS

Five review authors independently selected studies, assessed study quality and extracted data.

MAIN RESULTS

Five new studies have been added to this updated review, which now includes 11 randomised controlled trials involving 1457 patients. All the trials were of relatively short duration (12 weeks to 6 months). After treatment, patients treated with endothelin receptor antagonists could walk on average 33.7 metres (95% confidence interval [CI] 24.9 to 42.5 metres) further than those treated with placebo in a 6 minute walk test. Endothelin receptor antagonists improved more patients' World Health Organization/New York Heart Association (WHO/NYHA) functional class status than placebo (odds ratio [OR] 1.6; 95% confidence interval [CI] 1.2 to 2.1), and reduced the odds of functional class deterioration compared to placebo (OR 0.26; 95% CI 0.16 to 0.42 ). There was a trend for endothelin receptor antagonists to reduce mortality (OR 0.48; 95% CI 0.21 to 1.09), and limited data suggest that endothelin receptor antagonists improve Borg dyspnoea score and cardiopulmonary haemodynamics in symptomatic patients. Hepatic toxicity was not common, and endothelin receptor antagonists were well tolerated in this population.

AUTHORS' CONCLUSIONS

Endothelin receptor antagonists can increase exercise capacity, improve WHO/NYHA functional class, prevent WHO/NYHA functional class deterioration, reduce dyspnoea and improve cardiopulmonary haemodynamic variables in patients with pulmonary arterial hypertension with WHO/NYHA functional class II and III. However, there was only a trend towards endothelin receptor antagonists reducing mortality in patients with pulmonary arterial hypertension. Efficacy data are strongest in those with idiopathic pulmonary hypertension.