Treatment of pulmonary hypertension secondary to connective tissue diseases

The obstetric implications of pulmonary hypertension and lung transplant

Pulmonary hypertension (PH) is present when the mean pulmonary artery pressure is elevated to >20 mmHg as determined by right heart catheterization. It is categorized into five groups according to the underlying causes. Its presence is considered a contraindication to pregnancy for which therapeutic termination is usually advised due to grave maternal prognosis and pregnancy outcome. Nevertheless, pregnancies in affected women are increasingly reported, about half of which were unplanned, and two-thirds resulted in live births without increased foetal anomalies, notwithstanding increased risks of preterm birth, low birth weight, pre-eclampsia, other obstetric complications, and medical comorbidities, when managed under a multidisciplinary team in specialized centres. Successful lung transplant, the ultimate treatment for PH and other progressive lung diseases, restores fertility, and pregnancy is increasingly encountered, but there is a higher risk of graft rejection and mortality, compared with recipients of other organs. Preconception assessment is vital in optimizing maternal and pregnancy outcomes.

Safety and Efficacy of B-Cell Depletion with Rituximab for the Treatment of Systemic Sclerosis-associated Pulmonary Arterial Hypertension: A Multicenter, Double-Blind, Randomized, Placebo-controlled Trial

Rationale: Systemic sclerosis (SSc)-pulmonary arterial hypertension (PAH) is one of the most prevalent and deadly forms of PAH. B cells may contribute to SSc pathogenesis. Objectives: We investigated the safety and efficacy of B-cell depletion for SSc-PAH. Methods: In an NIH-sponsored, multicenter, double-blinded, randomized, placebo-controlled, proof-of-concept trial, 57 patients with SSc-PAH on stable-dose standard medical therapy received two infusions of 1,000 mg rituximab or placebo administered 2 weeks apart. The primary outcome measure was the change in 6-minute-walk distance (6MWD) at 24 weeks. Secondary endpoints included safety and invasive hemodynamics. We applied a machine learning approach to predict drug responsiveness. Measurements and Main Results: We randomized 57 subjects from 2010 to 2018. In the primary analysis, using data through Week 24, the adjusted mean change in 6MWD at 24 weeks favored the treatment arm but did not reach statistical significance (23.6 ± 11.1 m vs. 0.5 ± 9.7 m; P = 0.12). Although a negative study, when data through Week 48 were also considered, the estimated change in 6MWD at Week 24 was 25.5 ± 8.8 m for rituximab and 0.4 ± 7.4 m for placebo (P = 0.03). Rituximab treatment appeared to be safe and well tolerated. Low levels of RF (rheumatoid factor), IL-12, and IL-17 were sensitive and specific as favorable predictors of a rituximab response as measured by an improved 6MWD (receiver operating characteristic area under the curve, 0.88-0.95). Conclusions: B-cell depletion therapy is a potentially effective and safe adjuvant treatment for SSc-PAH. Future studies in these patients can confirm whether the identified biomarkers predict rituximab responsiveness. Clinical trial registered with www.clinicaltrails.gov (NCT01086540).

Prevalence of pulmonary hypertension in systemic lupus erythematosus: a meta-analysis

BACKGROUND AND AIMS

Pulmonary hypertension (PH) has been suggested to be associated with systemic lupus erythematosus (SLE). However, the results of prevalence studies on PH in SLE vary substantially. To derive a more precise estimation on the prevalence of PH in SLE, a meta-analysis was performed.

METHODS

Relevant literatures were searched in PubMed and EMBASE until November 2017. A total of 1366 articles were obtained after searching databases, and 23 studies were finally included in the meta-analysis. Heterogeneity test was performed, and publication bias was evaluated.

RESULTS

The result of analysis in random effect model showed that the pooled prevalence was 8% (95%CI 5-12%). There was no evidence of publication bias (p = 0.51). To evaluate the stability of our results, sensitivity analyses were performed, and the results showed no significant change when any one study was excluded. Subgroup analyses demonstrated that there were significant differences in PH prevalence in SLE patients of different gender, age, regions, year of publication, and diagnostic methods.

CONCLUSIONS

PH is prevalent in SLE patients, but it was significantly different between different gender, age, regions, year of publication, and diagnostic methods.

Therapy with intermittent pulse cyclophosphamide for pulmonary hypertension associated with systemic lupus erythematosus

The aim of this study was to compare the efficacy of intravenouscyclophosphamide(IVCYC) versus oral enalapril in mild or moderate pulmonary hypertension (PH) in systemic lupus erythematosus (SLE). Thirty-four patients with SLE who had systolic pulmonary artery pressure (SPAP) > 30mmHg by Doppler echocardiography were randomized to receive IVCYC (0.5g/mt2 body surface area, monthly), or oral enalapril (10mg/day) for six months. The primary outcome was the significant decrease in SPAP. An additional outcome measure included the improvement in the heart functional class (NYHA). Sixteen patients received cyclophosphamide and 18 enalapril. IVCYC decreased the median values of SPAP from 41 to 28mmHg (P < 0.001), and enalapril from 35 to 27mmHg (P 0.02). IVCYC reduced more than twice as much SPAP than enalapril (P 0.04). In those patients with SPAP ≥35mmHg, cyclophosphamidedecreased from 43 to 27mmHg (P 0.003), but enalapril was not effective (P 0.14). The NYHA functional class improved only in those with cyclophosphamide (P 0.021). Also IVCYC had a higher frequency of side effects including infections (RR 1.6; 95% CI, 1.001-2.47), and gastrointestinal side effects (RR 14.6; 95% CI,2.15-99.68). We concluded that IVCYC was effective in mild and moderate PH associated with SLE. Further research is needed to evaluate its long-term efficacy.

Pulmonary arterial hypertension associated to connective tissue diseases

Pulmonary arterial hypertension is a well-known complication of connective tissue diseases such as systemic sclerosis, systemic lupus erythematosus, mixed connective tissue diseases, and to a lesser extent, rheumatoid arthritis, dermatopolymyositis and primary Sjögren’s syndrome. In these patients, pulmonary hypertension may occur in association with left heart disease, interstitial fibrosis or as a result of a isolated pulmonary arteriopathy. The incidence of pulmonary arterial hypertension in the limited form of systemic sclerosis is about 10%. The pathophysiologic mechanisms leading to pulmonary arterial hypertension remain unknown. Symptoms and clinical presentation are very similar to idiopathic pulmonary arterial hypertension but mortality was confirmed to be higher. Echocardiography is the reference investigation for the detection of pulmonary arterial hypertension but the results should be confirmed by right heart catheterization. Treatment appears more complex as compared to idiopathic pulmonary arterial hypertension. Intravenous epoprostenol therapy has been shown to be effective in a special trail. Also, the endothelin receptor antagonists bosentan and sitaxentan, the phosphodyesterase-type-5 sildenafil and subcutaneous treprostinil have shown favourable results.

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.

Adverse Events in Connective Tissue Disease-Associated Pulmonary Arterial Hypertension

OBJECTIVE

Patients with connective tissue disease (CTD)-associated pulmonary arterial hypertension (PAH) have a poorer prognosis compared to those with idiopathic PAH, but little is known about the differences in treatment-related adverse events (AEs) and serious adverse events (SAEs) between these groups. This study was undertaken to characterize these differences.

METHODS

Individual patient-level data from 10 randomized controlled trials of therapies for PAH were obtained from the US Food and Drug Administration. Patients diagnosed as having either CTD-associated PAH or idiopathic PAH were included. A treatment-by-diagnosis interaction term was used to examine whether the effect of treatment on occurrence of AEs differed between patients with CTD-associated PAH and those with idiopathic PAH. Studies were pooled using fixed-effect models.

RESULTS

The study sample included 2,370 participants: 716 with CTD-associated PAH and 1,654 with idiopathic PAH. In the active treatment group compared to the placebo group, the risk of AEs was higher among patients with CTD-associated PAH than among those with idiopathic PAH (odds ratio [OR] 1.57, 95% confidence interval [95% CI] 1.00-2.47 versus OR 0.94, 95% CI 0.69-1.26; P for interaction = 0.061), but there was no difference in the risk of SAEs in analyses adjusted for age, race, sex, hemodynamic findings, and laboratory values. Despite the higher occurrence of AEs in patients with CTD-associated PAH assigned to active therapy compared to those receiving placebo, the risk of drug discontinuation due to an AE was similar to that in patients with idiopathic PAH assigned to active therapy (P for interaction = 0.27).

CONCLUSION

Patients with CTD-associated PAH experienced more treatment-related AEs compared to those with idiopathic PAH in therapeutic clinical trials. These findings suggest that the overall benefit of advanced therapies for PAH may be attenuated by the greater frequency of AEs.

Dexamethasone induces apoptosis in pulmonary arterial smooth muscle cells

Background

Dexamethasone suppressed inflammation and haemodynamic changes in an animal model of pulmonary arterial hypertension (PAH). A major target for dexamethasone actions is NF-κB, which is activated in pulmonary vascular cells and perivascular inflammatory cells in PAH. Reverse remodelling is an important concept in PAH disease therapy, and further to its anti-proliferative effects, we sought to explore whether dexamethasone augments pulmonary arterial smooth muscle cell (PASMC) apoptosis.

Methods

Analysis of apoptosis markers (caspase 3, in-situ DNA fragmentation) and NF-κB (p65 and phospho-IKK-α/β) activation was performed on lung tissue from rats with monocrotaline (MCT)-induced pulmonary hypertension (PH), before and after day 14–28 treatment with dexamethasone (5 mg/kg/day). PASMC were cultured from this rat PH model and from normal human lung following lung cancer surgery. Following stimulation with TNF-α (10 ng/ml), the effects of dexamethasone (10⁻⁸–10⁻⁶ M) and IKK2 (NF-κB) inhibition (AS602868, 0–3 μM (0-3×10⁻⁶ M) on IL-6 and CXCL8 release and apoptosis was determined by ELISA and by Hoechst staining. NF-κB activation was measured by TransAm assay.

Results

Dexamethasone treatment of rats with MCT-induced PH in vivo led to PASMC apoptosis as displayed by increased caspase 3 expression and DNA fragmentation. A similar effect was seen in vitro using TNF-α-simulated human and rat PASMC following both dexamethasone and IKK2 inhibition. Increased apoptosis was associated with a reduction in NF-κB activation and in IL-6 and CXCL8 release from PASMC.

Conclusions

Dexamethasone exerted reverse-remodelling effects by augmenting apoptosis and reversing inflammation in PASMC possibly via inhibition of NF-κB. Future PAH therapies may involve targeting these important inflammatory pathways.

Pulmonary arterial hypertension: challenges in translational research and a vision for change

Pulmonary arterial hypertension (PAH) is a vascular remodeling disease with a relentless course toward heart failure and early death. Existing PAH therapies, all of which were developed originally to treat systemic vascular diseases, cannot reverse the disease or markedly improve survival and are expensive. Although there has been a recent increase in the number of potential new therapies emerging from animal studies, less than 3% of the active PAH clinical trials are examining such therapies. There are many potential explanations for the translational gap in this complex multifactorial disease. We discuss these challenges and propose solutions that range from including clinical endpoints in animal studies and improving the rigor of human trials to conducting mechanistic early-phase trials and randomized trials with innovative designs based on personalized medicine principles. Global, independent patient and tissue registries and enhanced communication among academics, industry, and regulatory authorities are needed. The diversity of the mechanisms and pathology of PAH calls for broad comprehensive theories that encompass emerging evidence for contributions of metabolism and inflammation to PAH to support more effective therapeutic target identification.

Life-threatening complications of adult-onset Still's disease

Adult-onset Still's Disease (AOSD) since its description in 1971 has proven to be a very complex and challenging disease entity. This rare auto-inflammatory disease is classically described by the "Still's triad" of fever, rash, and arthritis, although the atypical cases frequently outnumber the typical ones. The exact pathogenesis and etiologic factors responsible for the clinical features remain largely obscure, despite recent suggestive cytokine biology findings. Diagnosis is made on clinical grounds, following the exclusion of mimickers of infectious, autoimmune or neoplastic etiology, with the additional consideration of non-specific laboratory abnormalities such as peripheral leukocytosis and elevation of serum ferritin and other acute phase reactants. The disease manifestations are protean and can include diverse complications, affecting multiple organ systems. Moreover, the severity of the organ involvement can vary considerably, representing a wide spectrum from the self-limited to severe. The mainstay of therapy has evolved from the traditional use of corticosteroids and oral immunosupressants to the newer targeted treatments with biologic agents. The scope of this review is to alert the clinician to the existence of life-threatening AOSD complications, namely the macrophage activation syndrome, disseminated intravascular coagulopathy, thrombotic thrombocytopenic purpura, diffuse alveolar hemorrhage, and pulmonary arterial hypertension. Such knowledge may lead in earlier recognition, prompt treatment, and, ideally, improved patient outcomes.

Pulmonary Arterial Hypertension in Patients with Primary Sjögren's Syndrome

Introduction. Primary Sjögren's syndrome (pSS) is an autoimmune epithelitis. Pulmonary arterial hypertension (PAH) is an important and severe complication, which is encountered in many collagen tissue disorders. Early diagnostic strategies are required to define it at the asymptomatic stage. Doppler echocardiography is an important, noninvasive screening test for PAH diagnosis. Objective. The aim of this present study is to define the frequency of PAH in patients with pSS and to reveal correlations with laboratory and clinical findings. Material and Methods. A total of 47 patients, who were diagnosed with pSS according to American-European Study Group criteria were enrolled in the study. After all patients were evaluated clinically and by laboratory tests, Doppler echocardiography was performed in the cardiology outpatient clinic. Systolic pulmonary artery pressure (SPAP) >30 mm Hg values, which were measured at the resting state, were accepted as significant for PAH. Results. Forty-seven patients with pSS were included in the study. The mean age of patients was 48 years and the mean disease duration was 5.3 years. PAH was defined in 11 of the 47 patients (23.4%). The SPAP value was over 35 mm Hg in 5 out of 11 patients, whereas six patients had SPAP measuring 30–35 mm Hg. While pulmonary hypertension was related with earlier age and shorter duration of disease (P = 0.04), there was no statistically significant correlation between SPAP increase and clinical findings (P > 0.05). Conclusion. We have defined high PAH frequency in patients with pSS. Since there are different data in the literature, it is obvious that large scale, multicentre studies are required.

Long-term survival of Japanese patients with pulmonary arterial hypertension treated with beraprost sodium, an oral prostacyclin analogue

OBJECTIVE

Beraprost was developed as the first oral prostacyclin analog to treat patients with pulmonary arterial hypertension (PAH). Although this drug demonstrates improvements in the patient's exercise capacity and symptoms, it carries a weak recommendation in the PAH evidence-based treatment algorithm due to a lack of durability of effects. However, this therapy remains a major treatment method in Japan due to its availability and inexpensive cost. The purpose of this study was to elucidate whether this drug exhibits durable effects on sustained overall survival.

METHODS

A comparison of survival benefits was completed among patients undergoing treatment with beraprost (n=35) or conventional therapy (n=44). In addition, the estimated survival calculated using the equation developed by the National Institutes of Health Registry was used for the analysis.

RESULTS

Although no significant differences were observed between the two groups using the Kaplan-Meier survival curve, a statistical difference was observed between the patients receiving high-dose beraprost therapy (>120 μg) and those receiving conventional therapy (5- and 10-year survival: 71.1% and 49.4% vs. 37.7% and 21.2%, respectively; p=0.0466). Moreover, the cumulative survival rates in the patients receiving beraprost were slightly better than the estimated survival rates. In the PAH patients with connective tissue diseases, a tendency towards better survival outcomes was observed in the group treated with beraprost.

CONCLUSION

This study suggests the survival benefits of high-dose beraprost therapy for patients with PAH. The retrospective nature of this study, however, makes it difficult to conclude definitively that beraprost exerts significant beneficial effects on survival.

Severe Pulmonary Hypertension in Primary Sjögren's Syndrome

A 65 year-old female with a history of xerostomia and xerophthalmia was presented with dyspnea on exertion (New York Heart Association class III). Echocardiography and cardiac catheterization demonstrated severe pulmonary hypertension (PH). Laboratory examinations showed positive anti-nuclear and anti-Ro/SS-A antibodies. Schirmer's test was positive and salivary gland scintigraphy revealed severely decreased tracer uptakes in both parotid and submandibular glands. By excluding other possible causes of PH during further examinations, she was diagnosed with severe PH associated with primary Sjögren's syndrome. Her dyspnea symptom was much improved with endothelin receptor antagonist and azathioprine.

The emergence of new therapeutic targets in pulmonary arterial hypertension: from now to the near future

Pulmonary arterial hypertension (PAH) is a vascular remodeling disease that pathologically increases pulmonary vascular resistance. Ultimately, this leads to right ventricular failure and premature death. Current therapeutic strategies are mainly designed to induce relaxation of the pulmonary arteries, but are not directly aimed to improve vascular remodeling that characterize PAH. Although these treatments modestly improve patient symptoms, pulmonary hemodynamics and survival, none of them are curative and approximately 15% of patients die within 1 year of medical follow-up despite treatment. Within the last 5 years, tremendous advances in our understanding of the PAH pathophysiology have arisen. These advances have a high potential for the development of better patient care by providing novel therapeutic targets. The goal of this report is to review the current PAH treatments, as well as novel therapies that will pave the future in this devastating disease.

Pulmonary hypertension in rheumatic diseases: epidemiology and pathogenesis

The focus of this review is to increase awareness of pulmonary arterial hypertension (PAH) in patients with rheumatic diseases. Epidemiology and pathogenesis of PAH in rheumatic diseases is reviewed, with recommendations for early screening and diagnosis and suggestion of possible role of immunosuppressive therapy in treatment for PAH in rheumatic diseases. A MEDLINE search for articles published between January 1970 and June 2012 was conducted using the following keywords: pulmonary hypertension, scleroderma, systemic sclerosis, pulmonary arterial hypertension, connective tissues disease, systemic lupus erythematosus, mixed connective tissue disease, rheumatoid arthritis, Sjogren's syndrome, vasculitis, sarcoidosis, inflammatory myopathies, dermatomyositis, ankylosing spondylitis, spondyloarthropathies, diagnosis and treatment. Pathogenesis and disease burden of PAH in rheumatic diseases was highlighted, with emphasis on early consideration and workup of PAH. Screening recommendations and treatment were touched upon. PAH is most commonly seen in systemic sclerosis and may be seen in isolation or in association with interstitial lung disease. Several pathophysiologic processes have been identified including an obliterative vasculopathy, veno-occlusive disease, formation of microthrombi and pulmonary fibrosis. PAH in systemic lupus erythematosus is associated with higher prevalence of antiphospholipid and anticardiolipin antibodies and the presence of Raynaud's phenomenon. Endothelial proliferation with vascular remodeling, abnormal coagulation with thrombus formation and immune-mediated vasculopathy are the postulated mechanisms. Improvement with immunosuppressive medications has been reported. Pulmonary fibrosis, extrinsic compression of pulmonary arteries and granulomatous vasculitis have been reported in patients with sarcoidosis. Intimal and medial hyperplasia with luminal narrowing has been observed in Sjogren's syndrome, mixed connective tissue disease and inflammatory myopathies. Pulmonary arterial hypertension (PAH) associated with rheumatic diseases carries a particularly grim prognosis with faster progression of disease and poor response to therapy. Though largely associated with systemic sclerosis, it is being increasingly recognized in other rheumatic diseases. An underlying inflammatory component may explain the poor response to therapy in patients with rheumatic diseases and is a rationale for consideration of immunosuppressive therapy in conjunction with vasodilator therapy in treatment for PAH. Further studies identifying pathogenetic pathways and possible targets of therapy, especially the role of immunomodulatory medications, are warranted.

Pulmonary hypertension in parenchymal lung disease

Idiopathic pulmonary arterial hypertension (IPAH) has been extensively investigated, although it represents a less common form of the pulmonary hypertension (PH) family, as shown by international registries. Interestingly, in types of PH that are encountered in parenchymal lung diseases such as interstitial lung diseases (ILDs), chronic obstructive pulmonary disease (COPD), and many other diffuse parenchymal lung diseases, some of which are very common, the available data is limited. In this paper, we try to browse in the latest available data regarding the occurrence, pathogenesis, and treatment of PH in chronic parenchymal lung diseases.

Sildenafil Reduces Inflammation and Prevents Pulmonary Arterial Remodeling of the Monocrotaline - induced Disease in the Wistar Rats

OBJECTIVES

Pulmonary arterial hypertension (PAH) is a rare and severe disease with incompletely under stood pathogenesis. PAH is associated with pulmonary arterial remodeling and inflammation. We evaluated the effects of Sildenafil on the Monocrotaline (MCT) -induced disease in Wistar rats, for potential benefit in the early phases of inflammation and vascular remodeling.

MATERIAL AND METHODS

MCT-injected rats, MCT-injected sildenafil-treated rats (starting day 1 with 2 x 0.2 mg/day; total of 2 mg/kgc/day) and saline-injected control rats were evaluated at day 14 and day 28 following MCT for pulmonary morphological changes - lesions, inflammation (inflammator y index), arterial morphometry (hypertrophy index), immunohistochemistry for smooth muscle cell marker.

OUTCOMES

The administration of sildenafil following MCT significantly reduced the severity of inflammation in the acute stage of the disease (reduction of the inflammatory index by 6.038% (p <0.05)) and prevented pulmonary arterial remodeling (reduction of the hypertrophy index by 7.306% (p<0.001)). It also improved survival in the early phase with a mortality rate during the first 14 days of 4 in the MCT- exposed rats vs 1 in the MCT-exposed sildenafil-treated rate.

CONCLUSIONS

Early administration of sildenafil in the MCT experimental PAH improves inflammation and survival, and prevents pulmonary vascular remodeling. Our study suggests that one of the mechanisms involved, besides vasodilatation and anti-proliferative effect, could be a direct anti-inflammatory effect of sildenafil.

Asymptomatic pulmonary hypertension in systemic lupus erythematosus

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a serious and often fatal complication of systemic lupus erythematosus (SLE). Because the diagnosis of PAH often is made years after symptom onset, early diagnostic strategies are essential. Doppler echocardiography currently is considered the noninvasive screening test of choice for evaluating pulmonary hypertension.

AIM

Screening for asymptomatic pulmonary hypertension in systemic lupus erythematosus patients using Doppler echocardiography, and correlating it with inflammatory parameters of the disease.

PATIENTS AND METHODS

Doppler echocardiography was performed in 74 patients with systemic lupus erythematosus over one year (66 adult and 8 juvenile), adult SLE included 57 patients with adult-onset and 9 patients with childhood-onset. Pulmonary hypertension was diagnosed if the peak systolic pressure gradient at the tricuspid valve was more than 30 mmHg. All patients were subjected to full history taking, rheumatological examination, laboratory studies and chest x-ray.

RESULTS

In seventy four SLE patients, the pulmonary hypertension was detected in 8 patients (10.8%), 7 adult-onset SLE patients (aged from 19 to 30 years) and 1 juvenile SLE (aged 12 years). The range of pulmonary artery systolic pressure was 34-61.2 mmHg (43.19 ± 9.28). No significant differences between patients with and those without pulmonary hypertension as regard clinical features. Significantly higher frequencies of rheumatoid factor and anti-cardiolipin antibodies were found in patients with pulmonary hypertension versus those without (P = 0.02, P = 0.008 respectively). Positive rheumatoid factor and ACL were significantly associated with occurrence of PAH in SLE (P = 0.007, P = 0.006 respectively). No significant correlations were found between pulmonary artery pressure, disease duration, SLE Disease Activity Index (SLEDAI), ESR, and anti-ds DNA.

CONCLUSION

Patients with SLE have an increased risk of pulmonary arterial hypertension. Echocardiography should be used as a screening tool in patients at high risk for development of pulmonary hypertension. Positive anti-cardiolipin antibodies and rheumatoid factor were significant predictors of pulmonary hypertension in our study.

Dexamethasone attenuates development of monocrotaline-induced pulmonary arterial hypertension

Immunity and inflammation are well established factors in the pathogenesis of pulmonary arterial hypertension (PAH). We aimed to investigate whether dexamethasone (Dex), a potent immunosuppressant, could prevent the development of monocrotaline (MCT)-induced PAH in rats as compared with pyrrolidine dithiocarbamate (PDTC) and its effect on the immune mechanism. PAH in rats (n = 66) was induced by MCT (50 mg/kg) injected intraperitoneally. Two days after MCT treatment, Dex (1.0 mg/kg) and PDTC (100 mg/kg) were administered once daily for 21 days. Samples were collected at 7, 14, and 21 days. Dex effectively inhibited MCT-induced PAH and reduced the T-helper (Th) 1 dominant cytokine response (interferon-γ) but up-regulated the Th2 one (interleukin 4). It increased the number of CD4+ T cells and decreased the number of CD8+ T cells around pulmonary arteries, upregulated the mRNA expression of fractalkine and downregulated that of CX3CR1 in the lung. Serum levels of interferon γ and interleukin 4 did not significantly differ from that of controls. Dex attenuated the process of MCT-induced PAH through its immunomodulatory property. Dex could be an appropriate therapy for PAH, although more studies are needed to define the appropriate treatment regimen.

New therapies for pulmonary arterial hypertension: an update on current bench to bedside translation

IMPORTANCE OF THE FIELD

Treatments of pulmonary arterial hypertension (PAH) that have so far proven efficacious are all based on the restoration of endothelium control of pulmonary vascular tone and structure, by administration of prostacyclins, endothelin receptor antagonists and phosphodiesterase-5 inhibitors. However, results remain unsatisfactory, with persistent high mortality, insufficient clinical improvement and no convincing report of any reversal of the disease process.

AREAS COVERED IN THIS REVIEW

New antiproliferative approaches that aim to actively limit pulmonary vascular remodeling are being sought. Several such treatments have shown promise in experimental models and in preliminary clinical studies. Noteworthy among these are dichloroacetate, survivin antagonists, nuclear factor of activated T-cell inhibitors, PPAR-gamma agonists, tyrosine kinase inhibitors, Rho-kinase inhibitors, statins, vasoactive intestinal peptide, soluble guanylate cyclase stimulators/activators, adrenomedullin, elastase inhibitors, serotonin reuptake inhibitors, anti-inflammatory agents, and bone marrow-derived progenitor cells.

WHAT THE READER WILL GAIN

Update on various strategies targeting proliferative, inflammatory and regenerating processes currently under evaluation in patients with PAH.

TAKE HOME MESSAGE

In spite of favorable results in experimental models, none of these strategies has achieved the ultimate goal of curing PAH. Further developments will depend on progress made in our pathobiological understanding of the disease and carefully designed randomized, controlled trials.

Comparison of baseline characteristics and survival between patients with idiopathic and connective tissue disease-related pulmonary arterial hypertension

BACKGROUND

Both idiopathic pulmonary arterial hypertension (IPAH) and pulmonary arterial hypertension (PAH) related to connective tissue diseases (CPAH) are classified in the group of PAH disorders. However, CPAH has a particularly worse prognosis than IPAH. Few studies have compared the clinical, functional and hemodynamic profiles of IPAH and CPAH.

METHODS

We performed a retrospective cohort study of patients with IPAH or CPAH. Demographic characteristics, functional status (FE), pulmonary function test and hemodynamic values at the time of diagnosis were compared between the two etiologies. Global cumulative survival rates free from transplantation (SFT) and survival according to date of diagnosis were analyzed.

RESULTS

Despite similar PAH severity, patients with CPAH showed a more severe baseline impairment of 6-minute walking test (6MWT) (307 +/- 116 m vs 378 +/- 101 m) and diffusion capacity of the lung for carbon monoxide (DLCO) (57 +/- 25% vs 75 +/- 30% of predicted) than IPAH (p < 0.01). Survival rates at 1, 3 and 5 years of follow-up were 87%, 71% and 63% for IPAH, and 70%, 53% and 42% for CPAH, respectively (p < 0.05). IPAH showed better survival when treatment was started after Year 2000 (p = 0.01). However, CPAH showed a poorer prognosis than IPAH in the more recent era (p < 0.05). CPAH (hazard ratio [HR] = 2.03), DLCO <80% (HR = 1.98) and treatment before Year 2000 (HR = 2.27) were associated with an independent increased risk of death or transplantation.

CONCLUSIONS

Despite similar functional and hemodynamic severity, patients with CPAH showed a more severe baseline impairment of 6MWT and DLCO and worse overall prognosis than IPAH. Both IPAH and CPAH survival improved in the current era. Nevertheless, CPAH still showed a poorer prognosis than IPAH.

Early combined treatment with cilostazol and bone marrow-derived endothelial progenitor cells markedly attenuates pulmonary arterial hypertension in rats

We investigated whether early combined cilostazol and bone marrow-derived endothelial progenitor cell (BMDEPC) treatment offers synergistic benefit in ameliorating monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH) in rats. Male Sprague-Dawley rats (n = 10/group) were randomized to receive saline injection only (group 1), MCT (70 mg/kg) (group 2), and MCT plus cilostazol (20 mg/kg/day) (group 3), MCT plus BMDEPCs (2.0 x 10(6) cells) (group 4), and MCT plus combined cilostazol/BMDEPCs (group 5). Intravenous BMDEPCs and oral cilostazol were given on day 3 after MCT administration. By day 42, connexin43 protein expression in right ventricle (RV) was reduced in group 2 compared with other groups and also was decreased in groups 3 and 4 compared with groups 1 and 5 (all p < 0.05). In addition, mRNA expressions of matrix metalloproteinase-9, tumor necrosis factor-alpha, and caspase-3 were higher, whereas Bcl-2 and endothelial nitric-oxide synthase were lower in lung and RV in group 2 compared with the other groups (all p < 0.05). The number of alveolar sacs and lung arterioles was lower in group 2 than in other groups and lower in groups 3 and 4 than in group 5 (all p < 0.05). RV systolic pressure (RVSP) and weight were increased in group 2 compared with the other groups (all p < 0.0001). Moreover, RVSP and RV-to-left ventricle plus septum weight ratio were higher in groups 3 and 4 than in groups 1 and 5 (p < 0.001) but showed no difference between groups 1 and 5. In conclusion, early combined autologous BMDEPC/cilostazol treatment is superior to BMDEPC or cilostazol only for preventing MCT-induced PAH.

Cilostazol therapy attenuates monocrotaline-induced pulmonary arterial hypertension in rat model

BACKGROUND

Pulmonary arterial hypertension (PAH) is characterized by a progressive increase in pulmonary vascular resistance caused by a proliferation of vascular endothelial and smooth muscle cells, resulting in occlusion of the lumen of small pulmonary arteries. Cilostazol, with its antiproliferative effects on vascular endothelial and smooth muscle cells, may ameliorate monocrotaline (MCT)-induced PAH in rats.

METHODS AND RESULTS

Male Sprague - Dawley rats (n=10/each group) were randomized to receive MCT (75 mg/kg) only (group 1), MCT plus cilostazol (20 mg .kg(-1 ). day(-1)) (group 2) and saline injection only (group 3). Hemodynamic measurement on day 28 following MCT treatment indicated the development of significant PAH on MCT-treated groups (p<0.0001). Cilostazol was given to group 2 orally on days 28-90. By day 90 following MCT treatment, the right ventricular (RV) systolic blood pressure and RV hypertrophy were significantly higher in group 1 than in groups 2 and 3 (all values of p<0.01). Additionally, connexin43 and endothelial nitric oxide synthase gene expressions of lung and RV, and Bcl-2 protein expression of RV, were significantly lower in group 1 than in groups 2 and 3 (all values of p<0.01). Furthermore, the number of alveolar sac and small arterioles of the lung were significantly lower in group 1 than in groups 2 and 3 (all values of p<0.01).

CONCLUSION

Cilostazol therapy effectively attenuates of MCT-induced PAH.

Transition from IV epoprostenol to subcutaneous treprostinil in pulmonary arterial hypertension: a controlled trial

BACKGROUND

We determined the relative efficacy of subcutaneous (SC) treprostinil in stable World Health Organization class II and III patients transitioned from IV epoprostenol.

METHODS

This was an 8-week, multicenter, randomized study in which patients were transitioned from IV epoprostenol to SC treprostinil or placebo over a period of up to 14 days and monitored carefully during and after the transition period for signs of deterioration. Patients with clinical deterioration were returned promptly to epoprostenol. Placebo or SC treprostinil doses were titrated in response to symptoms. Time to adjudicated clinical deterioration was compared between treatment groups, and exercise capacity, symptoms of disease, and safety were assessed throughout the study.

RESULTS

Twenty-two patients were enrolled and completed the study. Seven of 8 patients (88%) [corrected] withdrawn to placebo had clinical deterioration, while only 1 of 14 patients (7%) [corrected] withdrawn to SC treprostinil had clinical deterioration (p = 0.00023 based on a treatment comparison of time to deterioration). Analyses of exercise capacity and symptoms strongly supported the efficacy of SC treprostinil in epoprostenol-treated patients. Adverse events consisted of painful infusion site reactions and anticipated prostacyclin side effects.

CONCLUSIONS

SC treprostinil is effective in pulmonary arterial hypertension and prevents clinical deterioration and maintains functional status in patients transitioned from epoprostenol.

Fibrous remodeling of the pulmonary venous system in pulmonary arterial hypertension associated with connective tissue diseases

Pulmonary arterial hypertension is a severe complication of connective tissue diseases. It is currently well established that pulmonary arterial hypertension associated with connective tissue diseases such as systemic sclerosis is frequently less responsive or even refractory to pulmonary vasodilator therapies. In that setting, pulmonary venoocclusive disease is believed to contribute to treatment failures. We therefore hypothesized that pulmonary arterial hypertension associated with connective tissue diseases may be associated with obstructive lesions of pulmonary veins. Lung samples from 8 patients with pulmonary arterial hypertension associated with connective tissue disease (4 limited systemic sclerosis, 2 systemic lupus erythematosus, 1 mixed connective tissue diseases, and 1 rheumatoid arthritis) were studied by light microscopy and analyzed by immunohistochemistry (5 postmortem samples, 3 explants after lung transplantation). Findings were compared with 29 pulmonary arterial hypertension cases from patients displaying neither connective tissue diseases nor associated conditions. We found that (a) 6 (75%) of 8 patients with pulmonary arterial hypertension associated with connective tissue diseases showed significant obstructive pulmonary vascular lesions predominating in veins/preseptal venules, as compared with 5 (17.2%) of 29 non-connective tissue diseases control pulmonary arterial hypertension; (b) lesions of small muscular arteries were consistently present in pulmonary arterial hypertension associated with connective tissue diseases, showing mostly intimal fibrosis and thrombotic lesions; and (c) 6 of 8 lung samples from patients with pulmonary arterial hypertension associated with connective tissue diseases revealed perivascular inflammatory infiltration. In conclusion, our study highlights the fact that pulmonary arterial hypertension complicating the course of connective tissue diseases may be characterized by a more frequent involvement of pulmonary veins and may thus explain why these patients are less prone to respond to specific pulmonary arterial hypertension treatment as compared with idiopathic pulmonary arterial hypertension.

Serum Uric Acid as a Prognostic Predictor in Pulmonary Arterial Hypertension With Connective Tissue Disease

BACKGROUND

Pulmonary arterial hypertension (PAH) has been identified as a life threatening complication of connective tissue disease. However, the association between serum uric acid (UA) levels and long-term outcome in PAH with connective tissue disease has not been evaluated. We therefore assessed whether serum UA levels are related to the mortality of such patients.

METHODS AND RESULTS

We investigated 90 consecutive patients with connective tissue disease who were initially diagnosed with PAH by echocardiography, and assessed the long-term clinical outcome in populations with higher (> or = 4.7 mg/dL) and lower serum UA levels. Kaplan-Meier analysis showed that patients with higher median serum UA values had a significantly worse survival rate for any cause of death (54.5% versus 84.7%, log-rank, P < 0.01) and PAH-related death (72.7% versus 93.4%, log-rank, P < 0.01) than those with low values. Multivariate analysis showed that an elevated serum UA level was an independent predictor for survival (hazard ratio, 1.88, 95% CI [1.24- 2.84], P < 0.01).

CONCLUSION

Elevated serum UA levels are associated with a poor prognosis and can serve as a prognostic predictor for patients with PAH secondary to connective tissue disease.

Mycophenolate mofetil attenuates pulmonary arterial hypertension in rats

Pulmonary arterial hypertension (PAH) is characterized by abnormal proliferation of smooth muscle cells (SMCs), leading to occlusion of pulmonary arterioles, right ventricular (RV) hypertrophy, and death. We investigated whether mycophenolate mofetil (MMF), a potent immunosuppresssant, prevents the development of monocrotaline (MCT)-induced PAH in rats. MMF effectively decreased RV systolic pressure and RV hypertrophy, and reduced the medial thickness of pulmonary arteries. MMF significantly inhibited the number of proliferating cell nuclear antigen (PCNA)-positive cells, infiltration of macrophages, and expression of P-selectin and interleukin-6 on the endothelium of pulmonary arteries. The infiltration of T cells and mast cells was not affected by MMF. In vitro experiments revealed that mycophenolic acid (MPA), an active metabolite of MMF, dose-dependently inhibited proliferation of human pulmonary arterial SMCs. MMF attenuated the development of PAH through its anti-inflammatory and anti-proliferative properties. These findings provide new insight into the potential role of immunosuppressants in the treatment of PAH.

Pulmonary arterial hypertension and rheumatic diseases—from diagnosis to treatment

Survival rates in pulmonary arterial hypertension (PAH) associated with rheumatic diseases, in particular connective tissue diseases such as systemic sclerosis, are even lower than in idiopathic PAH. These low survival rates highlight the need for early diagnosis and treatment in these patients. Transthoracic Doppler-echocardiography is most often used for diagnostic screening of patients at risk. Other screening tests are serum pro-brain-natriuretic peptide (pro-BNP) and diffusion capacity for carbon monoxide (DLCO), which appear to be changed early in the course of the PAH associated with connective tissue diseases. The diagnosis needs to be confirmed by right heart catheterization, which is recommended in all patients with suspected PAH. Besides the conventional background therapy, a number of specific therapies have been evaluated in randomized controlled trials in the recent years. These therapies include prostacyclins and prostacyclin analogues, endothelin-receptor antagonists and phosphodiesterase-5 inhibitors. Response to treatment can be measured by exercise capacity (e.g. 6 min walk distance) and pro-BNP, although certain aspects of validation for these outcome measures are lacking in PAH associated with connective tissue diseases.

Immunosuppressive therapy in connective tissue diseases-associated pulmonary arterial hypertension

STUDY OBJECTIVE

Immune and inflammatory mechanisms could play a significant role in pulmonary arterial hypertension (PAH) genesis or progression, especially in patients with connective tissue diseases. Immunosuppressive therapy should be better evaluated in this setting.

STUDY DESIGN

Monocentric retrospective study.

PATIENTS

We reviewed the clinical and hemodynamic effects of immunosuppressants administered as first-line monotherapy to 28 consecutive patients with connective tissue disease-associated PAH.

INTERVENTIONS

All patients received a monthly IV bolus of cyclophosphamide, 600 mg/m2, for at least 3 months, and 22 of 28 patients received systemic glucocorticosteroids. Responders to immunosuppressive therapy were defined as patients who remained in New York Heart Association (NYHA) functional class I or II with sustained hemodynamic improvement after at least 1 year of immunosuppressive therapy without addition of prostanoids, phosphodiesterase type 5 inhibitors, or endothelin receptor antagonists.

RESULTS

Eight of 28 patients (systemic lupus erythematosus [SLE], n = 5; mixed connective tissue disease [MCTD], n = 3) [29%] were responders. These patients had a significantly improved 6-min walking distance (available in five patients) and a significant improvement in hemodynamic function. No patients with systemic sclerosis responded, while 5 of 12 patients with SLE and 3 of 8 patients with MCTD did respond. Survival analysis indicated that responders had a better survival than nonresponders. Patients with a lower baseline NYHA functional class and better baseline pulmonary hemodynamics (p < 0.05) were more likely to benefit from immunosuppressive therapy.

CONCLUSION

PAH associated with SLE or MCTD might respond to a treatment combining glucocorticosteroids and cyclophosphamide.

Pulmonary hypertension in a patient with adult-onset Stills disease

Pulmonary manifestations of adult-onset Still's disease (AOSD) include aseptic pneumonitis, pleural effusions, rarely acute respiratory distress syndrome, and restrictive lung disease. Pulmonary arterial hypertension (PAH) occurs with several rheumatologic diseases, however, has only been reported once in AOSD. We describe a 29-year-old woman with a 9-year history of AOSD, who developed PAH without any other obvious cause. Therefore, we conclude that this is likely a result of pulmonary vascular changes related to AOSD.

Acute manifestations of autoimmune connective tissue diseases

Autoimmune connective tissue diseases are common conditions that often present non-specifically. Clinicians in emergency departments and acute medical assessment units may face these patients. This article provides an overview for the non-specialist clinician on the acute manifestations that may occur in these patients.

Safety and Efficacy of IV Treprostinil for Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a life-threatening disease for which both continuous IV epoprostenol and continuous subcutaneous treprostinil have proven effective. With continuous IV treprostinil having potential advantages over both of the above therapies, we investigated the safety and efficacy of this regimen in patients with PAH.

METHODS

We conducted a 12-week, prospective, open-label, uncontrolled, multicenter study of continuous IV treprostinil in 16 patients with PAH that was idiopathic (n = 8), related to connective tissue disease (n = 6), or related to congenital heart disease (n = 2). The primary end point was change from baseline to week 12 in exercise capacity assessed by the 6-min walk (6MW) test.

RESULTS

Continuous IV treprostinil increased 6MW distance (mean +/- SE) by 82 m from baseline (319 +/- 22 m) to week 12 (400 +/- 26 m) [n = 14; p = 0.001]. There were also significant improvements in the secondary end points of Naughton-Balke treadmill time (p = 0.007), Borg dyspnea score (p = 0.008), and hemodynamics (mean pulmonary artery pressure, p = 0.03; cardiac index, p = 0.002; pulmonary vascular resistance, p = 0.001) at week 12 compared with baseline. Side effects were mild and consistent with those reported with prostacyclin treatment. One death, unrelated to study drug, occurred during the 12-week study in a patient who received 3 days of treprostinil and died 2 weeks later.

CONCLUSIONS

Long-term IV infusion of treprostinil is safe and appears to be effective for the treatment of patients with PAH.

Clinical aspects of pulmonary hypertension in patients with systemic lupus erythematosus and in patients with idiopathic pulmonary arterial hypertension

Clinical aspects and pathology of pulmonary hypertension (PH) in patients with systemic lupus erythematosus (SLE) have been reported to be similar to those in patients with idiopathic pulmonary arterial hypertension (IPAH). To determine whether PH in these patients is similar, we compared the clinical characteristics, hemodynamics at diagnosis, and survival in groups of patients with SLE-PH and IPAH. We reviewed the case records of 20 patients with SLE-PH and 34 patients with IPAH, who had been assessed by echocardiography or right cardiac catheterization at Asan Medical Center, Seoul, Korea, from January 1995 to October 2003. Clinical features, laboratory data, chest X-rays, electrocardiogram results, pulmonary function tests, pulmonary perfusion scans, echocardiographic findings, serologic profiles, and survival were compared in the two groups of patients. The mean follow-up period was 18.1+/-20.6 months for patients with SLE-PH and 33.0+/-23.4 months for patients with IPAH. During follow-up, 12 SLE-PH (60%) and 11 IPAH (32%) patients died. For SLE-PH, the 3-year survival rate was 44.9% and the 5-year survival rate was 16.8%. For IPAH, the 3-year survival rate was 73.4% and the 5-year survival rate was 68.2% (p=0.02). There were no other significant differences in clinical characteristics and laboratory data between the two groups. In contrast to previous reports that the prognosis of patients with pulmonary arterial hypertension associated with collagen vascular disease was better than that of patients with IPAH, we found that the prognosis of patients with SLE-PH was much worse than that of patients with IPAH.

Transition from Intravenous Epoprostenol to Intravenous Treprostinil in Pulmonary Hypertension

RATIONALE

Intravenous epoprostenol improves exercise capacity and survival in patients with pulmonary arterial hypertension. The prostacyclin analog treprostinil is also efficacious by subcutaneous infusion, is easier to administer, and has a longer half-life. With the demonstration of bioequivalence between subcutaneous and intravenous treprostinil, intravenous treprostinil may have an overall better risk-benefit profile than intravenous epoprostenol.

OBJECTIVE

To evaluate the safety and efficacy of transitioning patients with pulmonary arterial hypertension from intravenous epoprostenol to intravenous treprostinil.

METHODS

Patients enrolled in a 12-wk prospective open label study were switched from intravenous epoprostenol to intravenous treprostinil over 24 to 48 h. The intravenous treprostinil dose was adjusted to minimize symptoms/side effects.

RESULTS

Thirty-one patients (mean age, 43 yr; 22 women) were enrolled. Twenty-seven patients completed the protocol; 4 patients transitioned back to epoprostenol. Six-minute walk distance (n = 27; baseline, 438 +/- 16 m; Week 12, 439 +/- 16 m), Naughton-Balke treadmill test time (n = 26; baseline, 582 +/- 50 s; Week 12, 622 +/- 48 s), functional class, and Borg score were maintained with intravenous treprostinil at Week 12 versus intravenous epoprostenol before transition. At Week 12, mean pulmonary artery pressure increased 4 +/- 1 mm Hg (n = 27, p < 0.01), cardiac index decreased 0.4 +/- 0.1 L/min/m2 (n = 27, p = 0.01), and pulmonary vascular resistance increased 3 +/- 1 Wood units x m2 (n = 26, p < 0.01). No serious adverse events were attributed to treprostinil.

CONCLUSIONS

These data suggest that transition from intravenous epoprostenol to intravenous treprostinil is safe and effective; whether the hemodynamic differences associated with intravenous treprostinil are clinically important requires longer follow-up.

Les traitements de l’hypertension artérielle pulmonaire à l’heure de la T2A. Recommandations du groupe de travail “Maladies vasculaires pulmonaires” de la Société de pneumologie de langue française

Activity-based financing (that is, casemix-based hospital payments, known as T2A) is intended to harmonize and improve the fairness of remuneration of public and private hospitals. T2A will ultimately rely mainly on a flat rate per admission, set according to the diagnosis-related group (DRG). Although payment for drugs is usually included in the DRG price, some expensive drugs will be reimbursed on an additional cost basis after implementation of a "best practices" agreement. Four drugs used for treatment of pulmonary arterial hypertension are eligible for this additional reimbursement: 3 prostacyclin derivatives (intravenous epoprostenol, inhaled iloprost, and subcutaneous treprostinil), and oral bosentan, an endothelin receptor antagonist. The Pulmonary Vascular Diseases working group of the French Society of Pulmonary Medicine has developed guidelines for the best practices in use of these drugs.

One-year follow-up of the effects of sildenafil on pulmonary arterial hypertension and veno-occlusive disease

We hypothesized that chronic oral administration of the phosphodiesterase-5 inhibitor sildenafil could improve the exercise capacity and pulmonary hemodynamics in patients with pulmonary arterial hypertension (PAH) on the basis of previous short-term studies. We tested this hypothesis in 14 subjects with PAH, including seven patients with the idiopathic form and seven patients with atrial septal defects, but no other congenital heart abnormalities. Patients were subjected to a 6-min walk test and dyspnea was graded according to the Borg scale. Pulmonary flow and pressures were measured by Doppler echocardiography. Patients were given sildenafil, 75 mg orally three times a day, and followed up for 1 year. Sildenafil therapy resulted in the following changes: increase in the 6-min walk distance from a median value of 387 m (range 0 to 484 m) to 462 m (range 408 to 588 m; P < 0.01), improvement of the Borg dyspnea score from 4.0 (median value) to 3.0 (P < 0.01), and increased pulmonary flow (velocity-time integral) from a median value of 0.12 (range 0.08 to 0.25) to 0.23 (range 0.11 to 0.40; P < 0.01) with no changes in pulmonary pressures. In one patient with pulmonary veno-occlusive disease diagnosed by a lung biopsy, sildenafil had a better effect on the pulmonary wedge pressure than inhaled nitric oxide (15 and 29 mmHg, respectively, acute test). He walked 112 m at baseline and 408 m at one year. One patient died at 11 months of treatment. No other relevant events occurred. Thus, chronic administration of sildenafil improves the physical capacity of PAH patients and may be beneficial in selected cases of veno-occlusive disease.