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Background: Excessive proliferation of pulmonary artery smooth muscle cells (PASMCs) plays an important role in the development of idiopathic pulmonary arterial hypertension (IPAH), whereas a rise in cytosolic Ca2+ concentration triggers PASMC contraction and stimulates PASMC proliferation. Recently, we demonstrated that upregulation of the TRPC6 channel contributes to proliferation of PASMCs isolated from IPAH patients. This study sought to identify single-nucleotide polymorphisms (SNPs) in the TRPC6 gene promoter that are associated with IPAH and have functional significance in regulating TRPC6 activity in PASMCs., Methods and Results: Genomic DNA was isolated from blood samples of 237 normal subjects and 268 IPAH patients. Three biallelic SNPs, -361 (A/T), -254(C/G), and -218 (C/T), were identified in the 2000-bp sequence upstream of the transcriptional start site of TRPC6. Although the allele frequencies of the -361 and -218 SNPs were not different between the groups, the allele frequency of the -254(C-->G) SNP in IPAH patients (12%) was significantly higher than in normal subjects (6%; P<0.01). Genotype data showed that the percentage of -254G/G homozygotes in IPAH patients was 2.85 times that of normal subjects. Moreover, the -254(C-->G) SNP creates a binding sequence for nuclear factor-kappaB. Functional analyses revealed that the -254(C-->G) SNP enhanced nuclear factor-kappaB-mediated promoter activity and stimulated TRPC6 expression in PASMCs. Inhibition of nuclear factor-kappaB activity attenuated TRPC6 expression and decreased agonist-activated Ca2+ influx in PASMCs of IPAH patients harboring the -254G allele., Conclusions: These results suggest that the -254(C-->G) SNP may predispose individuals to an increased risk of IPAH by linking abnormal TRPC6 transcription to nuclear factor-kappaB, an inflammatory transcription factor.

Background: The use of systemic prostanoids in severe pulmonary arterial hypertension (PAH) is often limited by patient/physician dissatisfaction with the delivery methods. Complications associated with external pump-delivered continuous therapy include IV catheter-related bloodstream infections and subcutaneous infusion site pain. We therefore investigated a fully implantable intravascular delivery system for treprostinil infusion.Methods: A multicenter, prospective, single-arm, clinical trial (DelIVery for Pulmonary Arterial Hypertension) was conducted by using an implantable intravascular delivery system. The implanted pumps were refilled percutaneously at least every 12 weeks. The primary end point was the rate of catheter-related complications using the new model 10642 catheter compared with a predefined objective performance criterion of 2.5 per 1,000 patient-days based on the literature.Results: Patients (n = 60) with severe PAH (World Health Organization group 1) receiving a stable dose of IV treprostinil for at least 4 weeks received an implant device and were followed up for 12.1 ± 4.4 months. Six catheter-related complications occurred, corresponding to a complication rate of 0.27 per 1,000 patient-days. The 97.5% upper one-sided confidence bound of 0.59 was less than the predefined criterion of 2.5 per 1,000 patient-days (P < .0001). Plasma treprostinil levels at 1 week postimplantation were highly correlated with baseline levels (r = 0.91; P < .0001). The delivery system management time as reported by the patients was 2.5 ± 1.7 hours per week preimplantation, and this time decreased to 0.6 ± 0.8 hour per week at 6 months' postimplantation (P < .0001). All patients rated overall satisfaction with the implantable system as good, very good, or excellent at 6 weeks and 6 months. There were no catheter-related bloodstream infections or catheter occlusions.Conclusions: The implantable intravascular delivery system delivered treprostinil to patients with PAH with a low rate of catheter-related complications and a high rate of patient satisfaction.Trial Registry: ClinicalTrials.gov; No.: NCT01321073; URL: www.clinicaltrials.gov. [ABSTRACT FROM AUTHOR]

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The article explores the long-term safety and tolerability of sildenafil treatment of pulmonary arterial hypertension (PAH). Results reveal that, in general, long-term treatment of PAH initiated as sildenafil monotherapy was well tolerated. After three years, 60% of patients who entered the Sildenafil Use in Pulmonary Arterial Hypertension (SUPER)-1 trial improved or maintained their functional status, and 46% kept or improved 6-min walk distance (6MWD).

The article states that worldwide physician education and training have not kept pace with the progressions in detection, management and understanding of pulmonary hypertension (PH). It discusses the status of physician education and training in pulmonary hypertension, the paradigm for worldwide education and training in PH and the core proficiencies for HP education and training. The steps necessary for worldwide education and training in PH to proceed are discussed.

Pulmonary vascular remodeling,a major cause for the elevated pulmonary vascular resistance in patients with pulmonary arterial hypertension (PAH), is partially due to increased proliferation of pulmonary arterial smooth muscle cells (PASMC) in the media, resulting in vascular wall thickening. Platelet-derived growth factor (PDGF) is a potent mitogen that may be involved in the progression of PAH. Blockade of PDGF receptors has been demonstrated to have therapeutic potential for patients with severe pulmonary hypertension. Prednisolone is an immunosuppressant shown to have anti-inflammatory and antiproliferative effects on PASMC. This study was designed to investigate whether PDGF and prednisolone affect human PASMC proliferation by regulating the nuclear translocation of NF-κB (a transcription factor composed of 2 subunits, p50 and p65). Treatment of human PASMC with PDGF (10 ng/ml) significantly increased nuclear translocation of p50 and p65 subunits. Inhibition of NF-κB activation or nuclear translocation of p50/p65 significantly attenuated PDGF-induced PASMC proliferation (determined by [³H]thymidine incorporation). In the presence of prednisolone (200 µM), the PDGF-induced nuclear translocation of p50 and p65 subunits was markedly inhibited (P < 0.05 vs. the cells treated with PDGF alone). These results indicate that PDGF-induced nuclear translocation of NF-κB may play an important role in stimulating PASMC proliferation (and/or enhancing PASMC survival), whereas prednisolone may exert anti-inflammatory and antiproliferative effects on PASMC by inhibiting NF-κB nuclear translocation. [ABSTRACT FROM AUTHOR]

The article presents a study on the health benefits of sitaxsentan on the treatment of pulmonary arterial hypertension. It aimed to provide 1-year observational data with the two endothelin antagonists sitaxsentan and bosentan. There were patients treated with sitaxsentan at 100 mg. who had 96% overall survival and a 34% risk for a clinical worsening event for 1 year.

The article offers a delphi-consensus study with cluster analysis to determine the appropriate outcome measures in pulmonary arterial hypertension related to systemic sclerosis (PAH-SSc). Sixty nine PAH-SSc experts rated a list of disease domains and measurement tools. In the study, the experts judged the domains and tools as the best measure for randomized controlled trials in PAH-SSc.

Significant advances in the treatment of pulmonary arterial hypertension (PAH) have occurred over the last 10 years, starting with the approval of epoprostenol in 1998. Subsequently, multiple additional medications have received approval, including a subcutaneous prostacyclin, an inhaled prostacyclin, and oral medications in 2 separate classes. Over this same period, the classification of pulmonary hypertension has been revised with changes including the substitution of the term idiopathic for primary PAH and an expanded list of conditions felt to be associated with the development of PAH. Long-term follow-up studies have provided better information on prognosis and expected outcomes with treatment, with particularly valuable data on reassessment of prognosis after treatment with epoprostenol. Combination therapy is more frequently being used, and limited data on novel therapies such as stem cell transplantation have been published. The purpose of this review is to describe the current state of evidence for the diagnosis, prognosis, and treatment of the patient with PAH. [Copyright &y& Elsevier]

Background: Reports have linked anorexigen intake to an increased risk of pulmonary arterial hypertension (PAH). With the rise in anorexigen use in the latter half of the last decade, we established a surveillance network within the United States to monitor temporal trends in the number of reported cases of PAH. We also studied whether use of anorexigens and other drugs differed among patients with pulmonary hypertension of different etiologies. Methods: Newly diagnosed subjects (N = 1335) at 13 tertiary pulmonary hypertension centers were enrolled between January 1998 and June 2001. Patient-reported medication use was obtained by a telephone interview. Patients were classified as to the type of pulmonary hypertension. Poisson regression models were fitted to monthly case counts, and logistic regression methods were used to assess the association between type of pulmonary hypertension and medication use. Results: The average monthly number of reported cases of PAH and other categories of pulmonary hypertension did not change over the study period. Fenfluramine or dexfenfluramine use during the 5 years before the time of the interview was preferentially associated with PAH. Fenfluramine/dexfenfluramine use was particularly common in cases referred but found not to have pulmonary hypertension. Conclusions: No epidemic of anorexigen-related PAH was evident during the study period. As persons who had taken fenfluramine or dexfenfluramine were particularly likely to be referred for evaluation of pulmonary hypertension, it is unlikely that the failure to detect an anorexigen-induced rise in primary pulmonary hypertension was because of underascertainment. The association between fenfluramine derivatives and PAH is consistent with the risk elevations previously reported. [Copyright &y& Elsevier]

Pulmonary vascular medial hypertrophy caused by excessive pulmonary artery smooth muscle cell (PASMC) proliferation is a major cause for the elevated pulmonary vascular resistance in patients with idiopathic pulmonary arterial hypertension (IPAH). Increased Ca2+ influx is an important stimulus for PASMC proliferation. Transient receptor potential (TRP) channel genes encode Ca2+ channels that are responsible for Ca2+ entry during cell proliferation. Normal human PASMC expressed multiple canonical TRP (TRPC) isoforms; TRPC6 was highly expressed and TRPC3 was minimally expressed. The protein expression of TRPC6 in normal PASMC closely correlated with the expression of Ki67, suggesting that TRPC6 expression is involved in the transition of PASMC from quiescent phase to mitosis. In lung tissues and PASMC from IPAH patients, the mRNA and protein expression of TRPC3 and -6 were much higher than in those from normotensive or secondary pulmonary hypertension patients. Inhibition of TRPC6 expression with TRPC6 small interfering RNA markedly attenuated IPAH-PASMC proliferation. These results demonstrate that expression of TRPC channels correlates with the progression of the cell cycle in PASMC. TRPC channel overexpression may be partially responsible for the increased PASMC proliferation and pulmonary vascular medial hypertrophy in IPAH patients. [ABSTRACT FROM AUTHOR]

Study objectives: To assess the efficacy and safety of continuous subcutaneous infusion of treprostinil, a stable prostacyclin analogue, for treating pulmonary arterial hypertension (PAH) in patients with connective tissue disease (CTD). Design: Two multicenter, randomized, double-blind, placebo-controlled, prospective trials of treprostinil vs placebo in 470 patients with PAH. Patients: A subset of 90 patients with PAH and CTD, including systemic lupus erythematosus, diffuse scleroderma, limited scleroderma, and mixed CTD/overlap syndrome. Interventions: Patients received either treprostinil (initiated at 1.25 ng/kg/min, and titrated upward) or placebo via continuous subcutaneous infusion. The maximum dose of treprostinil allowed was 22.5 ng/kg/min. Measurements: Six-minute walk (6MW) distance and dyspnea-fatigue scores were determined at baseline, and at 6 weeks and 12 weeks. Hemodynamic measures were obtained at baseline and at 12 weeks. Results: At baseline, most patients had New York Heart Association class III symptoms. The mean baseline 6MW distance was 289 m (range, 60 to 448 m). The mean dose of treprostinil at week 12 was 8.4 ng/kg/min (range, 1.25 to 17.5 ng/kg/min). After 12 weeks, the change in cardiac index from baseline was + 0.2 ± 0.08 L/min/m² in the treprostinil group and -0.07 ± 0.07 L/min/m² in the placebo group (p = 0.007). The pulmonary vascular resistance index decreased by 4 ± 2 U &time;s m² in the treprostinil group and increased by 1 ± 1 U × m² in the placebo group (p = 0.006). The placebo-corrected median improvement from baseline in 6MW distance was 25 m in treprostinil-treated patients (p = 0.055); this improvement appeared to be dose related. Dyspnea fatigue scores also improved in the treprostinil group compared with the placebo group (p = 0.014). Adverse events included infusion site pain and typical side effects related to prostaglandins, and were tolerated by most patients. Conclusions: Continuous subcutaneous infusion of treprostinil in patients with PAH associated with CTD improved exercise capacity, symptoms of PAH, and hemodynamics. [ABSTRACT FROM AUTHOR]

Study objectives: We report on the long-term safety and efficacy of bosentan treatment in patients with pulmonary arterial hypertension (PAH). Background: In a preceding study, bosentan was well tolerated and significantly improved the exercise capacity and hemodynamics of patients with PAH after. 12 weeks of treatment. Design: The present study was an open-label extension to the preceding double-blind, placebocontrolled study of 32 patients with PAH (primary or associated with scleroderma) who received bosentan or placebo at 125 mg bid for 3 to 7 months. Patients: Twenty-nine of the original 32 patients received bosentan for an additional year (62.5 mg bid for 4 weeks and then 125 mg bid). Interventions: Study end points included long-term safety, 6-min walk distance at week 4, modified New York Heart Association (NYHA) functional class of PAH at month 12, and the occurrence of withdrawal due to clinical worsening. Additional exploratory analyses included a walk test at month 6 for 19 patients and hemodynamic assessment at month 12 for 11 patients. Results: At month 6, assessed patients continuing bosentan treatment maintained the improvement in walk distance observed at the end of the previous study (mean ± SEM, 60 ± 11 m), and patients starting bosentan treatment improved their walk distance by 45 ± 13 m. Long-term treatment with bosentan for > 1 year was associated with an improvement in hemodynamic parameters and modified NYHA functional class. Overall, bosentan treatment was well tolerated. No patient underwent transplantation or died. Conclusions: Long-term treatment with bosentan is safe and has sustained benefits on exercise capacity and hemodynamics in patients with PAH. [ABSTRACT FROM AUTHOR]

Endothelin (ET) has been identified as playing a fundamental role in many disease processes. Therapeutic efforts at interrupting ET's pathologic effects have focused on endothelin receptor antagonists (ERAs), of which two, bosentan and sitaxsentan, have been evaluated for the treatment of both primary and secondary pulmonary arterial hypertension (PAH). We discuss the multiple actions of ET, its role in various disease states, and the effects of ET receptor stimulation and blockade. Current classification and management of PAH are reviewed, along with the promise of greatly improved treatment generated by recent and ongoing clinical trials using ERAs. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Very low birth weight infants are vulnerable to hypotension and its associated complications. Vasopressors are used to raise blood pressure (BP), but indications for use are uncertain. Our objectives were (1) to study variations in BP stability among NICUs, (2) to investigate inter-NICU differences in vasopressor use, and (3) to address the association between intraventricular hemorrhage (IVH) and abnormal BPs. STUDY DESIGN: A total of 1288 infants with birth weight <1500 g were admitted to six NICUs in Massachusetts and Rhode Island over 21 months. The lowest and highest mean BPs were collected within the first 12 hours. Also recorded were the use of vasopressors within the first 24 hours and the occurrence of IVH. Logistic regressions were used to model outcomes, controlling for gestational age and illness severity using the Score for Neonatal Acute Physiology. RESULTS: Two of the six NICUs had significantly higher percentages of infants with at least one hypotensive BP, with prevalences of 24% to 45%. Percentages of infants treated with vasopressors ranged from 4% to 39%. This range of vasopressor use could not be explained by inter-NICU differences in birth weight, illness severity, or rates of hypotension. We found a borderline association between severe IVH and hypotension (odds ratio 1.6, p=0.055), but not between severe IVH and hypertension. CONCLUSION: Wide differences exist in the prevalence of hypotension, hypertension, and vasopressor use among NICUs. We also found an association between hypotension and IVH, but not between hypertension and IVH. [ABSTRACT FROM AUTHOR]

An editorial is presented which focuses on clinical features and prognosis of pulmonary arterial hypertension (PAH). Topics discussed include impact of PAH-targeted therapies on long-term outcomes; variables that reflect right ventricular function, stroke volume index, and right atrial pressure; and importance of follow-up assessment of hemodynamic parameters in decision making.

No abstract available Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

An abstract of the article "FREEDOM-M: Efficacy and Safety of Oral Treprostinil Diethanolamine as Monotherapy in Patients With Pulmonary Arterial Hypertension" by Lewis Rubin et al. is presented.

Abstract: The Third World Symposium on Pulmonary Arterial Hypertension served not only as a forum for the presentation of state-of-the art overviews of the pathobiologic and clinical aspects of pulmonary arterial hypertension (PAH), but also afforded an opportunity to the international scientific community to explore future directions of research and collaboration. This summary provides a brief overview of future directions in the field. [Copyright &y& Elsevier]

Background: Endothelin-1 is a potent vasoconstrictor and smooth-muscle mitogen. In a preliminary study, the orally administered dual endothelin-receptor antagonist bosentan improved exercise capacity and cardiopulmonary hemodynamics in patients with pulmonary arterial hypertension. The present trial investigated the effect of bosentan on exercise capacity in a larger number of patients and compared two doses. Methods: In this double-blind, placebo-controlled study, we randomly assigned 213 patients with pulmonary arterial hypertension (primary or associated with connective-tissue disease) to receive placebo or to receive 62.5 mg of bosentan twice daily for 4 weeks followed by either of two doses of bosentan (125 or 250 mg twice daily) for a minimum of 12 weeks. The primary end point was the degree of change in exercise capacity. Secondary end points included the change in the Borg dyspnea index, the change in the World Health Organization (WHO) functional class, and the time to clinical worsening. Results: At week 16, patients treated with bosentan had an improved six-minute walking distance; the mean difference between the placebo group and the combined bosentan groups was 44 m (95 percent confidence interval, 21 to 67; P<0.001). Bosentan also improved the Borg dyspnea index and WHO functional class and increased the time to clinical worsening. Conclusions: The endothelin-receptor antagonist bosentan is beneficial in patients with pulmonary arterial hypertension and is well tolerated at a dose of 125 mg twice daily. Endothelin-receptor antagonism with oral bosentan is an effective approach to therapy for pulmonary arterial hypertension. (N Engl J Med 2002;346:896-903.) [ABSTRACT FROM AUTHOR]

Pulmonary arterial hypertension (PAH) is a disease characterized by increased pulmonary pressures and chronic right heart failure. Therapies for moderate and severe PAH include subcutaneous (SQ) and intravenous (IV) prostanoids that improve symptoms and quality of life. However, treatment compliance can be limited by severe side effects and complications related to methods of drug administration. Inhaled prostanoids, which offer the advantage of direct delivery of the drug to the pulmonary circulation without need for invasive approaches, may serve as an alternative for patients unable to tolerate SQ/IV therapy. In this retrospective cohort study we collected clinical, hemodynamic, and functional data from 18 clinically stable patients with World Health Organization group I PAH seen in 6 large national PAH centers before and after transitioning to inhaled treprostinil from IV/SQ prostanoids. Before transition 15 patients had been receiving IV or SQ treprostinil (mean dose 73 ng/kg/min) and 3 patients had been on IV epoprostenol (mean dose 10 ng/kg/min) for an average duration of 113 ± 80 months. Although most patients who transitioned to inhaled treprostinil demonstrated no statistically significant worsening of hemodynamics or 6-minute walk distance, a minority demonstrated worsening of New York Heart Association functional class over a 7-month period. In conclusion, although transition of patients from IV/SQ prostanoids to inhaled treprostinil appears to be well tolerated in clinically stable patients, they should remain closely monitored for signs of clinical decompensation. [ABSTRACT FROM AUTHOR]

BACKGROUND The multinational AMBITION study demonstrated a 50% risk reduction in time to first clinical failure event (TtCF, a composite of death, hospitalization for worsening pulmonary arterial hypertension [PAH], disease progression, or unsatisfactory long-term clinical response) in treatment-naive Functional Class II and III PAH patients initiated on combination therapy (ambrisentan and tadalafil) vs monotherapy. A post-hoc analysis of AMBITION data by risk stratification, as determined by baseline REVEAL risk score, was undertaken to better assess the impact of combination therapy. METHODS Patients were randomized 2:1:1 to initial combination therapy with ambrisentan 10 mg plus tadalafil 40 mg vs either drug plus placebo, respectively. Baseline REVEAL risk scores in the 605 patients were grouped by low, intermediate, or high risk. Adjudicated outcomes (TtCF and post-hoc composite end-point of time to first PAH hospitalization or death) were assessed by risk group and treatment assignment. RESULTS At baseline, risk groups were similarly represented across treatment assignments as low (16%), intermediate (46%), and high (38%) risk. Greater risk was associated with worse outcome. At each level of risk, patients on combination therapy had significantly fewer TtCF or PAH hospitalization/death events relative to those on monotherapy, and discontinuations due to adverse events were not higher on combination therapy. CONCLUSIONS This post-hoc analysis comparing outcomes by REVEAL risk group has shown that, at all levels of risk, patients enrolled in AMBITION receiving initial combination therapy have superior outcomes and, even in those assessed as low risk, initial combination therapy was clinically beneficial. [ABSTRACT FROM AUTHOR]

Background Detailed hemodynamic data from the phase III PATENT-1 study of riociguat in patients with pulmonary arterial hypertension (PAH) were investigated. Methods Patients with PAH who were treatment naïve or pre-treated with endothelin receptor antagonists or non-intravenous prostanoids were randomly assigned to riociguat up to 2.5 mg 3 times a day or placebo. Hemodynamic parameters were assessed at baseline and week 12. Results Riociguat significantly decreased pulmonary vascular resistance in treatment-naïve ( n = 221; least squares [LS] mean difference −266 dyne∙sec∙cm −5 [95% confidence interval (CI) −357 to −175; p < 0.0001]) and pre-treated ( n = 222; LS mean difference −186 dyne∙sec ∙cm −5 [95% CI −252 to −120; p < 0.0001]) patients and significantly increased cardiac index (LS mean difference +0.7 [95% CI 0.5 to 0.8] and +0.5 [95% CI 0.3 to 0.7], respectively [both p < 0.0001]). Mean pulmonary artery pressure ( p = 0.0056 and p = 0.0019 for treatment-naïve and pre-treated patients, respectively), mean arterial pressure (both p < 0.0001), and systemic vascular resistance (both p < 0.0001) were significantly reduced, and there was an increase in mixed venous oxygen saturation ( p < 0.0001 and p = 0.0004, respectively). Results were similar in patients pre-treated with endothelin receptor antagonists and patients pre-treated with non-intravenous prostanoids. Improvements in 6-minute walking distance correlated very weakly with improvements in pulmonary vascular resistance ( r = −0.21 [95% CI −0.30 to −0.11; p < 0.0001]) and cardiac index ( r = 0.16 [95% CI 0.06 to 0.25; p < 0.0016]). Conclusions Riociguat significantly improved hemodynamic parameters in pre-treated and treatment-naïve patients with PAH. [ABSTRACT FROM AUTHOR]

The article presents a study on the use of primary end point of mortality and morbidity to examine the efficacy of macitentan, a novel dual endothelin-receptor antagonist in pulmonary arterial hypertension. The authors assign patients with hypertension to receive placebo and macitentan. It mentions that the primary end point was the period from the start of treatment to the first occurrence of a composite end point of death.

The article discusses a study that investigated the efficacy and side-effect profile of riociguat in patients with symptomatic pulmonary arterial hypertension. Oral anticoagulant agents and diuretics were administered. A table outlining baseline demographic and clinical attributes of the patients is provided. A graph illustrating the mean change from baseline in the six-minute walk distance is also shown.

Objectives: This study evaluated the safety and efficacy of ambrisentan for a period of 2 years in patients with pulmonary arterial hypertension (PAH). Background: Ambrisentan is an oral, once-daily endothelin receptor antagonist that is selective for the endothelin type A receptor. The ARIES-1 (Ambrisentan in Pulmonary Arterial Hypertension, Randomized, Double-Blind, Placebo-Controlled, Multicenter, Efficacy Studies) and ARIES-2 trials were the pivotal 12-week, placebo-controlled studies that led to the regulatory approval of ambrisentan (5 and 10 mg) for the treatment of PAH. Methods: In the ARIES-1 and -2 studies, and the subsequent long-term extension protocol, the ARIES-E study, 383 patients received ambrisentan (2.5, 5, or 10 mg). Efficacy and safety assessments are presented from the time of the first dose of ambrisentan for all patients with post-baseline data. Results: After 2 years of ambrisentan exposure, the mean change from baseline in 6-min walk distance was improved for the 5-mg (+23 m; 95% confidence interval: 9 to 38 m) and 10-mg (+28 m; 95% confidence interval: 11 to 45 m) groups. Estimates of survival and freedom from clinical worsening for the combined dose group were 94% and 83%, respectively, at 1 year and 88% and 72%, respectively, at 2 years. The annualized risk of aminotransferase abnormalities >3× the upper limit of normal was ∼2% per year; most of these events were mild and did not lead to discontinuation of drug. Conclusions: Two years of ambrisentan treatment was associated with sustained improvements in exercise capacity and a low risk of clinical worsening and death in patients with PAH. Ambrisentan was generally well tolerated and had a low risk of aminotransferase abnormalities over the 2-year study period. (A Long Term Study of Ambrisentan in Pulmonary Arterial Hypertension Subjects Having Completed AMB-320 or AMB-321; NCT00578786) [Copyright &y& Elsevier]

Abstract: Background: The stable prostanoid analogue treprostinil is approved as continuous infusion for treatment of pulmonary arterial hypertension. Unique drug characteristics may render this prostanoid feasible for inhalation therapy with a metered dose inhaler. Methods and results: Randomised open label investigation of acute haemodynamic effects, safety and tolerability of inhaled treprostinil delivered in seconds by a metered dose inhaler (MDI-TRE). Inhaled nitric oxide (NO) and MDI-TRE were applied once during right heart catheter investigation to 39 consecutive patients with pre-capillary pulmonary hypertension. Doses of 30μg, 45μg and 60μg MDI-TRE were investigated in separate groups of patients. Haemodynamics and blood gases were measured for 2h following treprostinil application. Acute haemodynamic responses to NO and MDI-TRE were comparable. MDI-TRE significantly improved haemodynamics compared to placebo inhalation. MDI-TRE induced effects were comparable to a historical control group that inhaled treprostinil from an ultrasonic nebuliser. The 120min area under the curve for PVR changes due to placebo, 30μg, 45μg or 60μg MDI-TRE was 1114±998, −870±940, −2450±2070 and −2000±900min*%. Reduction of systemic vascular resistance and pressure were not clinically relevant. No significant side effects were observed. No impact on ventilation/perfusion matching by treprostinil was demonstrated in 5 patients with pre-existing gas exchange limitations by use of the multiple inert gas elimination technique. Conclusions: The application of inhaled treprostinil with a metered dose inhaler is feasible and well tolerated. It induced a sustained pulmonary selective vasodilatation. [Copyright &y& Elsevier]

In 1998, during the Second World Symposium on Pulmonary Hypertension (PH) held in Evian, France, a clinical classification of PH was proposed. The aim of the Evian classification was to individualize different categories sharing similarities in pathophysiological mechanisms, clinical presentation, and therapeutic options. The Evian classification is now well accepted and widely used in clinical practice, especially in specialized centers. In addition, this classification has been used by the U.S. Food and Drug Administration and the European Agency for Drug Evaluation for the labeling of newly approved medications in PH. In 2003, during the Third World Symposium on Pulmonary Arterial Hypertension held in Venice, Italy, it was decided to maintain the general architecture and philosophy of the Evian classification. However, some modifications have been proposed, mainly to abandon the term “primary pulmonary hypertension” and to replace it with “idiopathic pulmonary hypertension”; to reclassify pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis; to update risk factors and associated conditions for pulmonary arterial hypertension and to propose guidelines in order to improve the classification of congenital systemic-to-pulmonary shunts. [Copyright &y& Elsevier]

Objectives: This study sought to assess the risks associated with right heart catheter procedures in patients with pulmonary hypertension. Background: Right heart catheterization, pulmonary vasoreactivity testing, and pulmonary angiography are established diagnostic tools in patients with pulmonary hypertension, but the risks associated with these procedures have not been systematically evaluated in a multicenter study. Methods: We performed a multicenter 5-year retrospective and 6-month prospective evaluation of serious adverse events related to right heart catheter procedures in patients with pulmonary hypertension, as defined by a mean pulmonary artery pressure >25 mm Hg at rest, undergoing right heart catheterization with or without pulmonary vasoreactivity testing or pulmonary angiography. Results: During the retrospective period, 5,727 right heart catheter procedures were reported, and 1,491 were reported from the prospective period, for a total of 7,218 right heart catheter procedures performed. The results from the retrospective and the prospective analyses were almost identical. The overall number of serious adverse events was 76 (1.1%, 95% confidence interval 0.8% to 1.3%). The most frequent complications were related to venous access (e.g., hematoma, pneumothorax), followed by arrhythmias and hypotensive episodes related to vagal reactions or pulmonary vasoreactivity testing. The vast majority of these complications were mild to moderate in intensity and resolved either spontaneously or after appropriate intervention. Four fatal events were recorded in association with any of the catheter procedures, resulting in an overall procedure-related mortality of 0.055% (95% confidence interval 0.01% to 0.099%). Conclusions: When performed in experienced centers, right heart catheter procedures in patients with pulmonary hypertension are associated with low morbidity and mortality rates. [Copyright &y& Elsevier]

Objectives: This study sought to investigate the effects of inhaled treprostinil on pulmonary hemodynamics and gas exchange in severe pulmonary hypertension. Background: Inhaled iloprost therapy has a proven clinical efficacy in pulmonary arterial hypertension, but this therapy necessitates 6 to 9 inhalation sessions per day. Treprostinil has a longer plasma half-life and might provide favorable properties when applied by inhalation. Methods: Three different studies were conducted on a total of 123 patients by means of right heart catheterization: 1) a randomized crossover-design study (44 patients), 2) a dose escalation study (31 patients), and 3) a study of reduction of inhalation time while keeping the dose fixed (48 patients). The primary end point was the change in pulmonary vascular resistance (PVR). Results: The mean pulmonary arterial pressure of the enrolled patients was approximately 50 mm Hg in all studies. In study 1, both treprostinil and iloprost at an inhaled dose of 7.5 μg displayed a comparable PVR decrease, with a significantly different time course (p < 0.001), treprostinil showing a more sustained effect on PVR (p < 0.0001) and fewer systemic side effects. In study 2, effects of inhalation were observed for 3 h. A near-maximal acute PVR decrease was observed at 30 μg treprostinil. In study 3, treprostinil was inhaled at increasing concentrations with a pulsed ultrasonic nebulizer, mimicking a metered dose inhaler. A dose of 15 μg treprostinil was inhaled with 18, 9, 3, 2 pulses, or 1 pulse, each mode achieving comparable, sustained pulmonary vasodilation without significant side effects. Conclusions: Inhaled treprostinil exerts sustained pulmonary vasodilation with excellent tolerability at relatively low doses and may be inhaled in a few breaths. [Copyright &y& Elsevier]

Objectives: The purpose of this study was to examine the efficacy and safety of four doses of ambrisentan, an oral endothelin type A receptor-selective antagonist, in patients with pulmonary arterial hypertension (PAH). Background: Pulmonary arterial hypertension is a life-threatening and progressive disease with limited treatment options. Endothelin is a vasoconstrictor and smooth muscle cell mitogen that plays a critical role in the pathogenesis and progression of PAH. Methods: In this double-blind, dose-ranging study, 64 patients with idiopathic PAH or PAH associated with collagen vascular disease, anorexigen use, or human immunodeficiency virus infection were randomized to receive 1, 2.5, 5, or 10 mg of ambrisentan once daily for 12 weeks followed by 12 weeks of open-label ambrisentan. The primary end point was an improvement from baseline in 6-min walk distance (6MWD); secondary end points included Borg dyspnea index, World Health Organization (WHO) functional class, a subject global assessment, and cardiopulmonary hemodynamics. Results: At 12 weeks, ambrisentan increased 6MWD (+36.1 m, p &#60; 0.0001) with similar and statistically significant increases for each dose group (range, +33.9 to +38.1 m). Improvements were also observed in Borg dyspnea index, WHO functional class, subject global assessment, mean pulmonary arterial pressure (−5.2 mm Hg, p &#60; 0.0001), and cardiac index (+0.33 l/min/m2, p &#60; 0.0008). Adverse events were mild and unrelated to dose, including the incidence of elevated serum aminotransferase concentrations >3 times the upper limit of normal (3.1%). Conclusions: Ambrisentan appears to improve exercise capacity, symptoms, and hemodynamics in patients with PAH. The incidence and severity of liver enzyme abnormalities appear to be low. [Copyright &y& Elsevier]

: ObjectivesThe purpose of this study was to investigate the effects of bosentan (125 or 250 mg twice daily) on echocardiographic and Doppler variables in 85 patients with World Health Organization class III or IV pulmonary arterial hypertension (PAH).: BackgroundBosentan, an orally active dual endothelin-receptor antagonist, improves symptoms, exercise capacity, and hemodynamics in patients with PAH.: MethodsPatients had primary pulmonary hypertension (84%) or PAH associated with connective tissue disease. Of these, 29 patients received placebo and 56 received bosentan (1:2 randomization). Six-minute walk tests and echocardiograms were performed at baseline and after 16 weeks of treatment.: ResultsBaseline characteristics were similar in the placebo and bosentan groups, and echocardiographic and Doppler findings were consistent with marked abnormalities of right ventricular (RV) and left ventricular (LV) structure and function that were due to PAH. The treatment effect on 6-min walking distance was 37 m in favor of bosentan (p = 0.036). Treatment effects of bosentan compared with placebo on other parameters were as follows: Doppler-derived cardiac index = +0.4 l/min/m2 (p = 0.007), LV early diastolic filling velocity = +10.5 cm/s (p = 0.003), LV end-diastolic area = +4.2 cm2 (p = 0.003), LV systolic eccentricity index = −0.12 (p = 0.047), RV end-systolic area = −2.3 cm2 (p = 0.057), RV:LV diastolic areas ratio = −0.64 (p = 0.007), Doppler RV index = −0.06 (p = 0.03), and percentage of patients with an improvement in pericardial effusion score = 17% (p = 0.05).: ConclusionsBosentan improves RV systolic function and LV early diastolic filling and leads to a decrease in RV dilation and an increase in LV size in patients with PAH. [Copyright &y& Elsevier]

Background: Pulmonary arterial hypertension (PAH) is a deadly disease with limited treatment options.Objectives: The objectives of this study were to assess the effects of bosentan, an orally active dual endothelin receptor antagonist, on exercise capacity and cardiopulmonary hemodynamics, as well as to assess its safety and tolerability in patients with severe PAH.Methods: In this double-blind, placebo-controlled, multicenter study, 32 patients with PAH (primary or associated with scleroderma) were randomized to receive bosentan for a minimum of 12 weeks (62.5 mg BID for 4 weeks, then 125 mg BID) or placebo. The primary end point was the change in exercise capacity. Secondary end points included changes in cardiopulmonary hemodynamics, Borg dyspnea index, and modified New York Heart Association (NYHA) functional class, as well as withdrawal due to clinical worsening.Results: Patients treated with bosentan improved their 6-minute walking distance. Fifteen bosentan-treated patients (71%) improved their walking distance from baseline to week 12 by >30 m, which is considered a clinically relevant improvement. The difference between treatment groups in the mean (±SEM) change at week 12 was 76 ± 31 m in favor of bosentan (95% CI, 12 to 139; P = 0.021). The improvement was maintained for at least 20 weeks. For cardiac index, the difference was 1.0 ± 0.2 L/min/m2 in favor of bosentan (95% CI, 0.6 to 1.4; P < 0.001). Bosentan significantly decreased pulmonary vascular resistance, whereas it was increased with placebo (P ≤ 0.001). Bosentan improved both the Borg dyspnea index and the NYHA functional class. All 3 withdrawals due to clinical worsening were in the placebo group (P = 0.033). The number and nature of adverse events were similar in the 2 groups.Conclusions: In these patients with PAH, bosentan increased exercise capacity and improved hemodynamics. These results, which have been summarized previously in a brief report, include all data up to 28 weeks of treatment and support the potential clinical value of endothelin receptor antagonists in the treatment of patients with PAH. [Copyright &y& Elsevier]

Several letters to the editor are presented in response to the article "Riociguat For the Treatment of Chronic Thromboembolic Pulmonary Hypertension," by H. A. Ghofrani and colleagues in the July 25, 2013 issue.

Background: Sildenafil inhibits phosphodiesterase type 5, an enzyme that metabolizes cyclic guanosine monophosphate, thereby enhancing the cyclic guanosine monophosphate–mediated relaxation and growth inhibition of vascular smooth-muscle cells, including those in the lung. Methods: In this double-blind, placebo-controlled study, we randomly assigned 278 patients with symptomatic pulmonary arterial hypertension (either idiopathic or associated with connective-tissue disease or with repaired congenital systemic-to-pulmonary shunts) to placebo or sildenafil (20, 40, or 80 mg) orally three times daily for 12 weeks. The primary end point was the change from baseline to week 12 in the distance walked in six minutes. The change in mean pulmonary-artery pressure and World Health Organization (WHO) functional class and the incidence of clinical worsening were also assessed, but the study was not powered to assess mortality. Patients completing the 12-week randomized study could enter a long-term extension study. Results: The distance walked in six minutes increased from baseline in all sildenafil groups; the mean placebo-corrected treatment effects were 45 m (+13.0 percent), 46 m (+13.3 percent), and 50 m (+14.7 percent) for 20, 40, and 80 mg of sildenafil, respectively (P<0.001 for all comparisons). All sildenafil doses reduced the mean pulmonary-artery pressure (P=0.04, P=0.01, and P<0.001, respectively), improved the WHO functional class (P=0.003, P<0.001, and P<0.001, respectively), and were associated with side effects such as flushing, dyspepsia, and diarrhea. The incidence of clinical worsening did not differ significantly between the patients treated with sildenafil and those treated with placebo. Among the 222 patients completing one year of treatment with sildenafil monotherapy, the improvement from baseline at one year in the distance walked in six minutes was 51 m. Conclusions: Sildenafil improves exercise capacity, WHO functional class, and hemodynamics in patients with symptomatic pulmonary arterial hypertension. N Engl J Med 2005;353:2148-57. [ABSTRACT FROM AUTHOR]

The numerous controlled clinical trials performed recently in pulmonary arterial hypertension (PAH) can allow us to abandon a clinical-based treatment strategy and adopt an evidence-based therapy. Both uncontrolled and controlled clinical trials with different compounds and procedures are reviewed and compared in order to define the efficacy-to-side-effect ratio of each treatment. A grading system for the level of evidence of treatments based on the number of favorable controlled clinical trials performed with a given compound is adopted; a treatment algorithm based on the evidence derived by clinical trials is proposed. It includes drugs approved by regulatory agencies for the treatment of patients with PAH and/or drugs available on the market for other indications. The algorithm is restricted to patients in New York Heart Association (NYHA) functional class III or IV because they represent the largest population included in controlled clinical trials. In addition, the different treatments have been evaluated mainly in sporadic, idiopathic PAH and in PAH associated with scleroderma or to anorexigen use. Extrapolation of these recommendations to the other PAH subgroups should be done with caution. Oral anticoagulation is proposed for all patients, whereas diuretic treatment and supplemental oxygen are indicated in cases of fluid retention and hypoxemia, respectively. High doses of calcium channel blockers are indicated only in the minority of patients who are responders to acute vasoreactivity testing. Nonresponders to acute vasoreactivity testing, or responders who remain in NYHA functional class III, should be considered candidates for treatment with either an endothelin receptor antagonist or a prostanoid. Continuous intravenous administration of epoprostenol is proposed as rescue treatment in NYHA functional class IV patients. Phosphodiesterase-V inhibitors should be considered in patients who have failed or are not candidates to other therapies. Combination therapy can be attempted in selected cases. Both balloon atrial septostomy and lung transplantation are indicated for refractory patients or where medical treatment is unavailable. [Copyright &y& Elsevier]

Endothelin receptor antagonism has emerged as an important therapeutic strategy in pulmonary arterial hypertension (PAH). Laboratory and clinical investigations have clearly shown that endothelin (ET)-1 is overexpressed in several forms of pulmonary vascular disease and likely plays a significant pathogenetic role in the development and progression of pulmonary vasculopathy. Oral endothelin receptor antagonists (ERAs) have been shown to improve pulmonary hemodynamics, exercise capacity, functional status, and clinical outcome in several randomized placebo-controlled trials. Bosentan, a dual-receptor antagonist, is approved by the U.S. Food and Drug Administration for class III and IV patients with PAH, based on two phase III trials. In addition to its efficacy as sole therapy, bosentan may have a role as part of a combination of drugs such as a prostanoid or sildenafil. The selective endothelin receptor-A antagonists sitaxsentan and ambrisentan are currently undergoing investigation. [Copyright &y& Elsevier]