A survey of diagnostic practices and the use of epoprostenol in patients with primary pulmonary hypertension

Epoprostenol-associated ascites in pulmonary arterial hypertension

The development of ascites in pulmonary arterial hypertension (PAH) in the absence of pre-existing hepatic dysfunction is usually associated with decompensated right heart failure or cardiac cirrhosis. Ascites in PAH has rarely been associated with intravenous epoprostenol, a synthetic form of the prostaglandin PGI2.

Intravenous prostacyclin-analogue therapy in pulmonary arterial hypertension - A review of the past, present and future

Therapy with intravenous prostacyclin analogues in patients with pulmonary arterial hypertension (PAH) has been established for decades and is an integral component of the current guidelines for the treatment of pulmonary hypertension. Initially, these drugs were infused by external pump systems via tunnelled right atrial catheters with the need for cooling and frequent exchange of drug reservoirs. Associated complications included, among others, catheter-related infections. More recently, fully implantable pump systems have been developed with drug reservoirs that are filled transcutaneously, allowing intervals between refills of several weeks. This technique results in a low rate of infections. Epoprostenol, iloprost and treprostinil have all been used intravenously in PAH, but titration, dosing and dose escalation in long-term therapy are not standardized. Intravenous prostacyclin analogues are still under-used, despite available data suggesting that early and broad application of these therapies as part of risk-oriented, guideline-directed combination therapy for patients with PAH may lead to a survival benefit. This review provides a detailed overview of the drugs, infusion systems and dosing strategies used for intravenous therapy in patients with PAH.

Lung transplantation: indications and contraindications

The selection of appropriate recipients for lung transplantation is an evolving discipline. As experience with the procedure has developed over the last decades, the identification of transplant candidates has also changed as transplant centers strive to safely provide the therapy to as many patients possible. The International Society for Heart and Lung Transplantation (ISHLT) has developed three editions of recipient selection guidelines. Published in 1998, 2006, and 2015, these guidelines represented the best information relevant to the appropriate selection of lung transplant candidates. A discussion of areas supported by the most robust scientific data will be undertaken, but in many aspects of recipient selection, there is a paucity of data upon which to rely. Therefore, it is ultimately the prerogative and responsibility of individual centers to determine, after carefully weighing the best evidence available, whether a patient is deemed a suitable candidate at a specific program. All possible indications and contraindications for transplantation will be reviewed with attention also given to the appropriate timing of referral and listing of patients with advanced lung disease to a transplant center.

A consensus document for the selection of lung transplant candidates: 2014--an update from the Pulmonary Transplantation Council of the International Society for Heart and Lung Transplantation

The appropriate selection of lung transplant recipients is an important determinant of outcomes. This consensus document is an update of the recipient selection guidelines published in 2006. The Pulmonary Council of the International Society for Heart and Lung Transplantation (ISHLT) organized a Writing Committee of international experts to provide consensus opinion regarding the appropriate timing of referral and listing of candidates for lung transplantation. A comprehensive search of the medical literature was conducted with the assistance of a medical librarian. Writing Committee members were assigned specific topics to research and discuss. The Chairs of the Writing Committee were responsible for evaluating the completeness of the literature search, providing editorial support for the manuscript, and organizing group discussions regarding its content. The consensus document makes specific recommendations regarding the timing of referral and of listing for lung transplantation. These recommendations include discussions not present in previous ISHLT guidelines, including lung allocation scores, bridging to transplant with mechanical circulatory and ventilator support, and expanded indications for lung transplantation. In the absence of high-grade evidence to support decision making, these consensus guidelines remain part of a continuum of expert opinion based on available studies and personal experience. Some positions are immutable. Although transplant is rightly a treatment of last resort for end-stage lung disease, early referral allows proper evaluation and thorough patient education. Subsequent waiting list activation implies a tacit agreement that transplant offers a significant individual survival advantage. It is both the challenge and the responsibility of the transplant community globally to ensure organ allocation maximizes the potential benefits of a scarce resource, thereby achieving that advantage.

Pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a chronic and progressive disease leading to right heart failure and ultimately death if untreated. The first classification of PH was proposed in 1973. In 2008, the fourth World Symposium on PH held in Dana Point (California, USA) revised previous classifications. Currently, PH is devided into five subgroups. Group 1 includes patients suffering from idiopathic or familial PAH with or without germline mutations. Patients with a diagnosis of PAH should systematically been screened regarding to underlying mutations of BMPR2 gene (bone morphogenetic protein receptor type 2) or more rarely of ACVRL1 (activine receptor-like kinase type 1), ENG (endogline) or Smad8 genes. Pulmonary veno occusive disease and pulmonary capillary hemagiomatosis are individualized and designated as clinical group 1'. Group 2 'Pulmonary hypertension due to left heart diseases' is divided into three sub-groups: systolic dysfonction, diastolic dysfonction and valvular dysfonction. Group 3 'Pulmonary hypertension due to respiratory diseases' includes a heterogenous subgroup of respiratory diseases like PH due to pulmonary fibrosis, COPD, lung emphysema or interstitial lung disease for exemple. Group 4 includes chronic thromboembolic pulmonary hypertension without any distinction of proximal or distal forms. Group 5 regroup PH patients with unclear multifactorial mechanisms. Invasive hemodynamic assessment with right heart catheterization is requested to confirm the definite diagnosis of PH showing a resting mean pulmonary artery pressure (mPAP) of ≥ 25 mmHg and a normal pulmonary capillary wedge pressure (PCWP) of ≤ 15 mmHg. The assessment of PCWP may allow the distinction between pre-capillary and post-capillary PH (PCWP > 15 mmHg). Echocardiography is an important tool in the management of patients with underlying suspicion of PH. The European Society of Cardiology and the European Respiratory Society (ESC-ERS) guidelines specify its role, essentially in the screening proposing criteria for estimating the presence of PH mainly based on tricuspid regurgitation peak velocity and systolic artery pressure (sPAP). The therapy of PAH consists of non-specific drugs including oral anticoagulation and diuretics as well as PAH specific therapy. Diuretics are one of the most important treatment in the setting of PH because right heart failure leads to fluid retention, hepatic congestion, ascites and peripheral edema. Current recommendations propose oral anticoagulation aiming for targeting an International Normalized Ratio (INR) between 1.5-2.5. Target INR for patients displaying chronic thromboembolic PH is between 2–3. Better understanding in pathophysiological mechanisms of PH over the past quarter of a century has led to the development of medical therapeutics, even though no cure for PAH exists. Several specific therapeutic agents were developed for the medical management of PAH including prostanoids (epoprostenol, trepoprostenil, iloprost), endothelin receptor antagonists (bosentan, ambrisentan) and phosphodiesterase type 5 inhibitors (sildenafil, tadalafil). This review discusses the current state of art regarding to epidemiologic aspects of PH, diagnostic approaches and the current classification of PH. In addition, currently available specific PAH therapy is discussed as well as future treatments.

Design and delivery of an e-learning curriculum for physicians involved in the management of pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) is a condition that affects more than 25 million individuals worldwide and causes premature disability and death. Despite advances in our understanding of this condition, education and training of health professionals has not kept pace with the rapid changes in diagnosis and treatment. The net effects of this gap between advancing knowledge and limited educational opportunity likely include clinically significant delays in both the diagnosis and commencement of effective evidence-based treatment - an unacceptable outcome for patients with a lethal condition.

AIM

The Actelion Clinical Excellence Programme (ACEP) is an e-learning postgraduate curriculum, the purpose of which is to educate and mentor healthcare professionals, both theoretically and practically, in the diagnosis and treatment of patients with all forms of PH. This article reports on the development and delivery of the programme and outcomes from its first year of operation.

RESULTS

Forty-three healthcare professionals from 22 institutions were enroled in the first iteration of the programme. In the 6 months from May to October 2011, participants successfully completed 285 lectures and/or activities. Overall, the programme was considered easily accessible, comprehensive in terms of both quality and quantity, provided an efficient means of self-paced learning, and was a highly regarded as reference source. Ninety-five per cent of participants said that they intended to change their clinical practice as a result of the information presented in the programme.

CONCLUSION

ACEP represents a successful physician-industry partnership, which has resulted in a significant impact on clinical teaching and awareness of PH.

Pulmonary hypertension in systemic lupus erythematosus: a systematic review and analysis of 642 cases in Chinese population

Pulmonary hypertension (PH) is an increasingly recognized complication of systemic lupus erythematosus (SLE). To develop a more comprehensive understanding of the clinical and pathological characteristics of pulmonary hypertension associated with systemic lupus erythematosus (PH/SLE) in the Chinese population, a systematic review of the literature up to 2012 was conducted. Six hundred and forty-two Chinese PH/SLE cases from 22 studies were identified as well documented and further analyzed. Transthoracic echocardiography (TTE), X-ray, electrocardiogram and right heart catheterization (RHC) were performed to diagnose PH in SLE patients. The mean age of subjects was 35.5 years, the male to female ratio was 1:14, and the mean duration of SLE when PH was diagnosed was 10.7 years. The prevalence of PH in SLE was 2.8–23.3 %. Symptoms were usually nonspecific, and the observed clinical characteristics include Raynaud’s phenomenon (41.4 %), serous effusion (27.7 %), positive RNP (51.5 %) and positive ACL (46.6 %). Gold standard RHC is strongly recommended, especially for those who had resting pulmonary arterial systolic pressure >30 mmHg on TTE with the aforementioned clinical characteristics. Corticosteroids, immunosuppressants and vasodilators were the most common medications employed in treatment. Early identification and standard PH treatment with intensive SLE treatment can improve the prognosis.

Prostanoids for Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a severe condition that markedly reduces exercise capacity and survival in the affected patient population. PAH includes primary pulmonary hypertension (PPH) and pulmonary hypertension associated with collagen vascular diseases, congenital systemic-to-pulmonary shunts, portal hypertension and HIV infection. All these conditions share virtually identical obstructive pathologic changes of the pulmonary microcirculation and probably similar pathobiologic processes. The pathophysiology is characterized by a progressive increase in pulmonary vascular resistance, leading to right ventricular failure and death. Prostacyclin is an endogenous substance that is produced by vascular endothelial cells and induces vasodilatation, inhibition of platelet activity, and antiproliferative effects. A dysregulation of prostacyclin metabolic pathways has been shown in patients with PAH and this represents the rationale for the exogenous therapeutic administration of this substance. The clinical use of prostacyclin in patients with PAH has been made possible by the synthesis of stable analogs that possess different pharmacokinetic properties but share similar pharmacodynamic effects. Experience in humans has been initially collected with epoprostenol, which is a synthetic salt of prostacyclin. Epoprostenol has a short half-life in the circulation and requires continuous administration by the intravenous route by means of infusion pumps and permanent tunnelized catheters. In addition, epoprostenol is unstable at room temperature, and the complex delivery system required is associated with several adverse effects and potentially serious complications. For these reasons, alternatives to intravenous epoprostenol have been sought and this has led to the development of analogs that can be administered subcutaneously (treprostinil), orally (beraprost sodium) or by inhalation (iloprost). Three unblinded clinical trials and several uncontrolled trials have shown that treatment with epoprostenol improved symptoms and exercise capacity in New York Heart Association (NYHA) class III and IV PAH patients and also survival in patients with PPH. Subcutaneous treprostinil improved symptoms, exercise, hemodynamics and clinical events in the largest clinical trial ever performed in PAH, but local infusion site reactions limited efficacy in a proportion of patients. Oral beraprost sodium improved exercise capacity only in patients with PPH and is the only prostacyclin analog that has also been tested in NYHA class II patients. Inhaled iloprost has improved symptoms, exercise capacity and clinical events in patients with PAH and inoperable chronic thromboembolic pulmonary hypertension. The favorable effects of prostanoids observed in all studies coupled with different profiles of adverse events and tolerability for each prostacyclin analog allow the unique opportunity to select the most appropriate compound for the individual patient with PAH.

Pulmonary hypertension-"state of the art" management in 2012

Pulmonary artery hypertension (PAH) is a pathological condition of small pulmonary arteries, characterised by vascular proliferation and remodelling. The pulmonary artery pressure and pulmonary vascular resistance progressively rise, leading to right heart failure and death. Pulmonary artery hypertension may be secondary to various conditions, or it may be idiopathic where no underlying cause is identifiable. Earlier, only symptomatic treatment was available for such patients which did not change the natural history of the disease. However, over the years, improvement in understanding the pathogenesis has resulted in the development of targeted approaches to the treatment of PAH. Survival advantage has also been shown with some of the pharmacologic agents. This review article discusses the current management strategy for PAH with special emphasis on an idiopathic variety, in an Indian context.

The potential for inhaled treprostinil in the treatment of pulmonary arterial hypertension

Inhaled treprostinil is a safe and well-tolerated approved pharmaceutical for the treatment of pulmonary arterial hypertension. In a series of open-label studies and in the pivotal trial with 253 patients, this long-acting prostacyclin analogue demonstrated pronounced pulmonary selectivity of vasodilatory effects, improved physical capacity and excellent tolerability and safety following aerosol administration. For efficient treatment, only four daily inhalations of treprostinil are necessary compared with six to nine in iloprost aerosol therapy. This review describes in detail the development of inhaled treprostinil, starting with intravenous epoprostenol followed by inhaled iloprost and subcutaneous treprostinil, all three representing well-established and widely approved prostanoid therapies for pulmonary hypertension.

In order to circumvent the drawbacks of intravenous epoprostenol, stable prostacyclin analogues with similar pharmacological properties have been investigated. In addition, alternative routes of administration have been proposed and evaluated, mainly inhaled and subcutaneous delivery. The concept of inhaled treprostinil was to combine the pulmonary selectivity of an aerosolized vasodilator with the long-acting effects of a stable prostacyclin analogue.

Pulmonary arterial hypertension remains, however, a severe, life-threatening disease, in spite of the enormous progress in specific drug therapy over the last decade. Therefore, further improvement of drug therapy will be essential, with clear potential for inhaled treprostinil: a reduction of inhalation frequency and duration would markedly improve quality of life and compliance, and a longer-lasting local prostanoid effect might further enhance the efficacy of inhaled treprostinil. The advantageous pharmacological properties of treprostinil offer the opportunity to establish a convenient metered dose inhaler as a delivery system, to combine inhaled treprostinil with available or future drugs for pulmonary arterial hypertension, or to develop sustained release formulations of treprostinil suitable for inhalation based on liposomes or biodegradable nanoparticles.

ACUTE EFFECTS OF SILDENAFIL IN PATIENTS WITH PRIMARY PULMONARY HYPERTENSION RECEIVING EPOPROSTENOL

Epoprostenol therapy has improved survival in primary pulmonary hypertension; however, only two thirds of patients are alive 3 years after starting treatment. Combined therapy with sildenafil, a phosphodiesterase 5 inhibitor, may provide additional benefit. The authors prospectively evaluated the acute hemodynamic and biochemical effects of sildenafil and inhaled nitric oxide, alone and in combination, in 8 patients with primary pulmonary hypertension receiving chronic epoprostenol. Average duration of epoprostenol therapy was 2.9 +/- 1.6 years (mean +/- SD) and mean dose was 25.7 +/- 10.8 ng/kg/min. A single 50 mg dose of sildenafil decreased mean pulmonary arterial pressure 10% (P<.05), increased cardiac output 8%, and decreased pulmonary vascular resistance 24% (P<.005). Although nitric oxide led to a similar decrease in mean pulmonary arterial pressure of 10% (P<.05), cardiac output was unchanged, resulting in a decrease in pulmonary vascular resistance of only 13%, which was not statistically different from baseline. These results suggest that sildenafil has greater acute hemodynamic effects than nitric oxide and that it can further reduce pulmonary vascular resistance in patients already demonstrating a benefit from chronic epoprostenol.

[Thyroid dysfunction in patients with pulmonary arterial hypertension. A cohort study of 58 patients]

BACKGROUND AND OBJECTIVE

Thyroid disease (TD) is more prevalent in patients with pulmonary arterial hypertension (PAH) than in the general population. The frequency and the cause of this association are not well established. We aimed to quantify and analyze the incidence and characteristics of TD in a cohort of PAH patients (idiopathic or preferentially associated with systemic diseases) and review the literature.

PATIENTS AND METHOD

Fifty eight PAH patients were prospectively studied, according to a previously established protocol (that included right heart catheterization); TSH, T(4), and antithyroglobulin and antiperoxidase antibodies were determined. TD was defined as an abnormal TSH level and/or elevated antithyroid antibodies (TAbs). Clinical, biological and hemodynamic variables were compared between patients with and without TD.

RESULTS

TD was detected in 30 patients (51%): high TSH levels were observed in 21 (36,21%); hyperthyroidism in 2 (3,45%); and TAbs in 16 of 54 (27,59%), 7 of whom were euthyroid. In the TD group, PAH evolution time was longer (4,62 vs 2,61 years; P=.005, CI 95%, 0,63-3,38), more patients were in functional class IV (13;43,3% vs 5;15,8%, P=.046, CI 95% ,0,05-11,75), cardiac output was lower (P=.032, CI 95%, 3,16-4,89) and epoprostenol treatment was more frequently used (14;46,6% vs 4;14,3%, P=.008, CI 95%, 1,46-18,85; OR=5,25).

CONCLUSIONS

The frequency of TD detected in this PAH cohort reaches 51% and it was associated with a longer evolution time of PAH and worse hemodynamic situation. Although epoprostenol was used more frequently in TD patients, a causal relationship with TD could not be established.

Dosing considerations in the use of intravenous prostanoids in pulmonary arterial hypertension: an experience-based review

BACKGROUND

Intravenous (IV) prostanoid therapy remains arguably the most effective treatment of advanced pulmonary arterial hypertension (PAH) despite the introduction of newer molecules from different drug classes.

METHODS

Literature regarding the properties, efficacy, safety, dosing, and cost of IV prostanoids was reviewed. In addition, a survey of physicians who treat PAH in the United States was conducted to assess IV prostanoid use in clinical practice.

RESULTS

Clinical studies have demonstrated that the 2 prostanoids available for IV administration in the United States, epoprostenol and treprostinil, improve exercise capacity, dyspnea, and cardiopulmonary hemodynamics in patients with PAH. Furthermore, epoprostenol has been shown to improve quality of life, functional class, and survival. The safety profiles of epoprostenol and IV treprostinil during short-term therapy appear comparable. Potential differences in the biochemical properties of these 2 drugs may have clinical implications. Whereas long-term data with subcutaneous treprostinil have been published, such data for IV treprostinil are not currently available. The physician survey revealed differences in the common maintenance doses used for both drugs, with IV treprostinil dosing approximately twice that of epoprostenol. These differences in dose have a direct bearing on the cost of therapy.

CONCLUSIONS

The unique properties of epoprostenol and treprostinil translate into clinical differences, which can influence the amount of drug used to achieve satisfactory patient improvement in the acute and long-term settings.

Treprostinil for pulmonary hypertension

Treprostinil is a stable, long-acting prostacyclin analogue which can be administered as a continuous subcutaneous infusion using a portable miniature delivery system. Subcutaneous treprostinil has been shown in a large multicenter randomized controlled trial to improve exercise capacity, clinical state, functional class, pulmonary hemodynamics, and quality of life in patients with pulmonary arterial hypertension, an uncommon disease of poor prognosis. Side effects include facial flush, headache, jaw pain, abdominal cramping, and diarrhea, all typical of prostacyclin, and manageable by symptom-directed dose adjustments, and infusion site pain which may make further treatment impossible in 7%-10% of the patients. Long-term survival in pulmonary arterial hypertension patients treated with subcutaneous treprostinil is similar to that reported with intravenous epoprostenol. There are uncontrolled data suggesting efficacy of subcutaneous treprostinil in chronic thromboembolic pulmonary hypertension. Treprostinil can also be administered intravenously, although increased doses, up to 2-3 times those given subcutaneously, appear to be needed to obtain the same efficacy. Preliminary results of a randomized controlled trial of inhaled treprostinil on top of bosentan and sildenafil therapies have shown significance on the primary endpoint, which was exercise capacity as assessed by the distance walked in 6 minutes. Trials of oral formulations of treprostinil have been initiated.

Review: Therapeutic advances in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction, in situ thrombosis, and vascular remodeling of small pulmonary arteries inducing increased pulmonary arterial resistance. Conventional treatment is based on life style modification and nonspecific treatment (warfarine, diuretics, oxygen). Calcium channel blockers are vasodilatators that have been shown to be of great efficacy in a very specific subpopulation of patients with PAH. For the majority of patients, specific PAH therapies are still lacking. Numerous studies evaluating prostacyclin agonists, endothelin-receptor antagonists, and phosphodiesterase type 5 inhibitors are now available to guide therapeutic choices. Despite those important advances there is still no cure for PAH. Fortunately, research is ongoing and many drugs show promises.

Epidemiology of Pulmonary Arterial Hypertension

Progress in understanding the basic biology and the development of new therapies for pulmonary arterial hypertension have led to improvements in survival. This article reviews clinically important changes in the classification of the pulmonary hypertensive diseases, as well as the epidemiology of various forms of pulmonary hypertension. The risk factors for the development of pulmonary arterial hypertension, prognostic markers, and the effects of current therapies on survival are discussed.

Management of heart failure with pulmonary hypertension

Heart failure (HF) and pulmonary hypertension (PH) coexist frequently and contribute to each other. Because PH often is an insidious disease, the cornerstone of management is the early identification and treatment of its underlying causes, such as left-sided heart disease, left to right shunts, and pulmonary disorders. A practical clinical classification has been proposed by the Third World Symposium on Pulmonary Arterial Hypertension for the purpose of diagnosis and treatment of PH. Thromboembolic pulmonary hypertension should always be considered. Recent studies using vasodilators such as prostacyclins and endothelin antagonists give new hope in the otherwise poor prognosis of idiopathic pulmonary arterial hypertension and its related conditions. Despite optimum medical management, transplantation (lung/heart-lung) remains the choice in severely symptomatic patients.

Traitement de l’hypertension artérielle pulmonaire

Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction, in situ thrombosis, and vascular remodeling of small pulmonary arteries. It induces a fixed pulmonary arterial obstruction, persistent elevation of pulmonary arterial resistance, and eventually right heart failure. Conventional therapy is based on simple measures (exercise limitation) and nonspecific treatments (warfarin, diuretics, and oxygen). Pure vasodilators, such as calcium channel blockers, are effective only in a minority of patients who have an acute response to vasodilator testing. Intravenous prostacyclin (epoprostenol) and endothelin receptor blockers have vasodilator and antiproliferative properties. Epoprostenol therapy has significantly improved PAH prognosis and remains the first-line treatment for patients with the most severe disease. Bosentan is an interesting first-line treatment for NYHA functional class III patients. Availability of novel specific drugs (endothelin receptor type A antagonists, prostacyclin analogues, type 5 phosphodiesterase inhibitors) is opening new perspectives in PAH treatment. The long-term benefit of these drugs remains to be evaluated and their respective place in treatment of these patients is still uncertain. The evolution of therapy from vasodilators to antiproliferative agents reflects the advancement in our understanding of the mechanisms mediating pulmonary arterial hypertension.

Prednisolone inhibits proliferation of cultured pulmonary artery smooth muscle cells of patients with idiopathic pulmonary arterial hypertension

BACKGROUND

Idiopathic pulmonary arterial hypertension (IPAH) is associated with proliferation of smooth muscle cells (SMCs) in small pulmonary arteries. There is no therapy that specifically inhibits SMC proliferation. Recent studies reported that prednisolone (PSL) inhibits the postangioplasty proliferation of SMCs in atherosclerotic arteries. In this study, we tested the hypothesis that PSL has antiproliferative effects on pulmonary artery SMCs of patients with IPAH.

METHODS AND RESULTS

Pulmonary artery SMCs were harvested from the pulmonary arteries of 6 patients with IPAH who underwent lung transplantation. Control SMCs were obtained from 5 patients with bronchogenic carcinoma who underwent lung lobectomy. After incubation in the presence of platelet-derived growth factor (PDGF), PSL was added at different concentrations and cell proliferation was assessed by 3H-thymidine incorporation. PSL (2x10(-4) and 2x10(-3) mol/L) significantly inhibited PDGF-stimulated proliferation (P<0.05) of SMCs from patients with IPAH but did not affect cell viability of SMCs, as confirmed by trypan blue staining. In cell cycle analysis using a microscope-based multiparameter laser scanning cytometer, PSL inhibited the progression of SMCs from G(0)/G1 to the S phase. This inhibition was associated with increased p27 expression level. PSL (2x10(-4) mol/L) also inhibited PDGF-induced SMC migration.

CONCLUSIONS

Our results indicate that PSL has an antiproliferative effect on cultured SMCs of pulmonary arteries from patients with IPAH and suggest that PSL may be potentially useful therapeutically in patients with IPAH.

Hypertension artérielle pulmonaire

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a rare condition characterised by progressively elevated pulmonary arterial resistance leading to right heart failure.

STATE OF THE ART

A recent classification distinguishes idiopathic PAH, familial PAH and PAH secondary to other conditions (connective tissue disease, congenital heart disease, portal hypertension, human immunodeficiency virus infection or appetite suppressant exposure). Echocardiography is the initial investigation of choice for non-invasive detection of PAH but measurement of pulmonary pressures and cardiac output during right-heart catheterization are necessary to confirm the diagnosis of PAH. Conventional treatment includes non-specific drugs (warfarin, diuretics, oxygen). Intravenous epoprostenol is the first-line treatment for the most severely affected patients. In less severe cases, the first-line treatment may include bosentan or a prostacyclin analogue.

PERSPECTIVES AND CONCLUSIONS

Recent advances in the management of PAH have markedly improved prognosis. The avai-lability of novel specific drugs including type 5 phosphodiesterase inhibitors offers novel therapeutic perspectives but their exact role in the treatment of PAH is still uncertain. The evolution of therapy from vasodilators to antiproliferative agents reflects the advancement in our understanding of the mechanisms mediating pulmonary arterial hypertension.

Pulmonary and systemic hemodynamic responses to intravenous prostacyclin in broilers

The eicosanoid vasodilator prostacyclin (PGI2) reduces resistance to pulmonary blood flow and attenuates pulmonary hypertension in mammals. However, sparse information is available regarding the responsiveness of the avian pulmonary vasculature to PGI2. Accordingly, in 3 experiments we evaluated the pulmonary vascular responses to PGI2 in male broilers. In experiment 1, infusing PGI2 (10 microg/min) into clinically healthy broilers did not reduce their pulmonary vascular resistance (PVR) but did reduce their pulmonary arterial pressure (PAP) by lowering their cardiac output. Within 4 min after stopping the PGI2 infusion, the cardiac output and PAP returned to preinfusion levels. In experiment 2, the responses to PGI2 were evaluated after arachidonic acid (AA) had been infused to preconstrict the pulmonary vasculature. The AA infusion (400 microg/min) consistently triggered dramatic, sustained pulmonary vasoconstriction (increased PVR) and pulmonary hypertension (increased PAP). Concurrent PGI2 infusions did not reduce PVR but did reduce PAP by lowering cardiac output. Within 4 min after stopping the PGI2 infusion, PAP and cardiac output returned to their previous (hypertensive) levels attributable to the ongoing AA infusion. In experiment 3, PGI2 was infused (10 microg/min) into clinically healthy (PAP < or = 24 mmHg) or subclinically hypertensive (PAP > or = 27 mmHg) broilers. Throughout this experiment broilers in the hypertensive group had higher PAP values than broilers in the healthy group. The PGI2 infusion reduced PAP in both groups but did not reduce PVR. Instead, the pulmonary hypotensive response to PGI2 infusion was associated with a reduction in cardiac output in both groups. In all 3 experiments PGI2 reduced PAP by reducing cardiac output rather than by reducing PVR. There was no evidence that PGI2 acts as an effective pulmonary vasodilator in broilers regardless of whether their pulmonary vasculature was apparently normal (clinically healthy), had been pharmacologically preconstricted (AA infusion), or initially exhibited the vasoconstriction that is typical of the pathogenesis of pulmonary hypertension syndrome in broilers (PAP > or = 27 mmHg). The consistent failure of PGI2 to elicit pulmonary vasodilation in this study suggests fundamental differences in AA metabolism or the etiology of pulmonary hypertension may exist when broilers are compared with mammals.

[Treatments for pulmonary arterial hypertension]

PURPOSE

Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction, in situ thrombosis and vascular remodeling of small pulmonary arteries inducing a fixed pulmonary arterial obstruction and persistent elevation of pulmonary arterial resistance. Conventional treatment is based on simple measures (exercise limitation) and non-specific drugs (warfarine, diuretics, oxygen).

CURRENT KNOWLEDGE AND KEY POINTS

Pure vasodilators like calcium channel antagonists have little or no effect on the vast majority of patients, presumably because fixed pulmonary arteriopathy predominate over vasoconstriction. Intravenous prostacyclin (epoprostenol) and endothelin receptor antagonists have vasodilator and antiproliferative properties. Epoprostenol therapy has resulted in significant improvements in prognosis of this disease and this drug remains the first-line treatment of the most severe patients. Bosentan is an interesting first-line treatment for NYHA functional class III patients. Availability of novel specific drugs (endothelin receptor type A antagonists, prostacyclin analogues, type 5 phosphodiesterase inhibitors) open new perspectives in treatment of PAH. The long-term benefit of these drugs remains to be evaluated and their respective place in treatment of these patients is still uncertain. We here present the different therapeutic alternatives available in the PAH and propose an algorithm for treatment of these patients.

FUTURE PROSPECTS AND PROJECTS

The evolution of therapy from vasodilators to antiproliferative agents reflects the advancement in our understanding of the mechanisms mediating pulmonary arterial hypertension.

Effects of epoprostenol on right ventricular hypertrophy and dilatation in pulmonary hypertension

OBJECTIVES

To gain more knowledge of changes in main pulmonary artery flow and right ventricular mass and volumes in patients with pulmonary hypertension during epoprostenol therapy.

METHODS

Eleven patients (9 women) were evaluated before the start of therapy and every 4 months thereafter. Right and left ventricular volumes and masses were measured by cine MRI. Flow was measured with MRI velocity quantification. At the same times, 6-min walking tests were performed. Right-heart catheterizations were performed at baseline and after 1 year.

RESULTS

Right ventricular mass in the patient group was significantly higher from that in a control group of healthy volunteers (95 +/- 26 g vs 42 +/- 10 g, p < 0.05 [mean +/- SD]), whereas the stroke volume was lower (34 +/- 11 mL vs 81 +/- 11 mL, p < 0.05). The greatest improvement in right ventricular stroke volume (to 41 +/- 11 mL, p < 0.05) took place in the first 4 months. During the 1-year follow-up, right ventricular end-diastolic volume and mass did not change, and mean pulmonary artery pressure remained nearly stable at 55 mm Hg at baseline and 53 mm Hg after 1 year. Pulmonary vascular resistance decreased by 12.5% (p = 0.06).

CONCLUSIONS

From these data we conclude that epoprostenol lowers pulmonary vascular resistance, leading to an increase in pulmonary artery flow. This increase in pulmonary artery flow corresponds well with the increase in 6-min walking distance and can be noninvasively monitored by MRI (flow quantification). Right ventricular dilatation and hypertrophy are not reversed by epoprostenol therapy, but do not progress either.

[Ten years' experience in continuous intravenous epoprostenol therapy in severe pulmonary arterial hypertension]

INTRODUCTION

Primary pulmonary hypertension and its associated forms is a progressive and often fatal disease, the course of which has been favourably modified by prostacyclin therapy in the last decade.

OBJECTIVE

The aim of this study is to analize retrospectively the efficacy of continuous intravenous epoprostenol (synthetic prostacyclin) therapy in pulmonary arterial hypertension, and to compare it with conventional therapy (anticoagulants, digoxin and diuretics).

METHODS

Between 1990-2000, 31 patients with severe precapillary pulmonary hypertension in functional class III or IV went on continuous intravenous epoprostenol therapy, administered by a portable infusion pump through a Hickman catheter. We compared their survival with a group of 16 patients treated with conventional therapy alone.

RESULTS

Time of follow-up was 33.25 months in the prostacyclin group and 20 months in the conventional group. The one- three- and five- year survival rates were 86%, 50% and 38% respectively for patients treated with epoprostenol compared with 40%, 40% and 8% survival rates at idetical periods for patients treated conventionally (p = 0,02). Functional class and the mean distance walked in the 6 minutes test were improved in patients treated with prostacyclin (p < 0,01). Serious complications attributable to the delivery system included 3 deaths, mainly due to infection.

CONCLUSION

Continuous intravenous epoprostenol therapy improves survival and exercise capacity in patients with severe pulmonary arterial hypertension despite potentially serious complications attributable to the delivery system.

Primary pulmonary hypertension: Current therapy

Because the causes of primary pulmonary hypertension (PPH) remains unknown, the therapeutic approach of the disease can be only empirical, based on the pathology and pathobiology of pulmonary circulation. Despite the inability to cure the disease, therapeutic advances over the past 20 years have contributed to an improvement of quality of life and prolonged survival in PPH patients. Current therapeutic approach of PPH mostly includes limitation of physical activity, long-term anticoagulation, and vasodilator therapy. Among all tested oral vasodilators, calcium-channel blockers are the most efficient long-term therapies by improving symptoms and hemodynamics in a subset of PPH patients (10% to 15%) who acutely respond to such drugs. Acute pulmonary vasodilator response to inhalation of nitric oxide can predict acute and chronic responses to oral calcium-channel blockers. A better understanding of the pathogenesis of PPH has changed the focus of medical treatments from purely chronic vasodilator therapy to the evaluation of agents, such as prostaglandins, that may reverse the proliferation of pulmonary vascular cells and result in regression of the pulmonary vascular hypertrophy and remodeling. Long-term treatment with intravenous epoprostenol (prostaglandin I(2) or prostacyclin) improves exercise capacity, hemodynamics and survival in most patients with PPH in functional class NYHA III or IV, and may be currently considered as the "gold standard" therapy for severe patients. However, response to long-term epoprostenol therapy may be incomplete, adverse effects are common, and survival remains unsatisfactory (55% at 5 years). In such patients with severe pulmonary hypertension refractory to medical therapy, atrioseptostomy and lung transplantation can be indicated.

Cellular pathophysiology and therapy of pulmonary hypertension

The identification of several mutations of the bone morphogenetic protein receptor 2 (BMPR2) gene, a member of the transforming growth factor beta receptor family, gives hope for new insights into the pathophysiology of pulmonary hypertension. Genetic predisposition might dictate the responses of pulmonary artery fibroblasts, smooth muscle cells, and endothelial cells, as well as platelets and leukocytes, or their specific interactions with different extrinsic factors. These cells possess distinct subtypes and interact with each other. Pulmonary hypertension is associated with vasoconstriction, remodeling, and in situ thrombosis of the pulmonary arteries, but the initial events and their relationship to the genetic background are presently unknown. Current therapeutic approaches are based on our knowledge of the physiologic regulation of pulmonary artery tone, pathophysiologic changes, and our clinical experience with different treatment strategies. Beyond diuretics and anticoagulants, prostaglandins are generally accepted therapeutic agents for primary pulmonary hypertension and related diseases, whereas high-dose calcium-channel blockers are reserved for a small subset of patients, those who respond favorably to vasodilators in an acute test. Long-term intravenous prostacyclin infusion has become the most important specific therapy for primary pulmonary hypertension and associated diseases. However, this therapy is hampered by catheter complications and systemic side effects. Alternative application routes of prostacyclin or its stable analogs may avoid these problems. Inhaled application of the prostacyclin analog iloprost results in predominant pulmonary vasodilation with few systemic side effects and may possess clinical efficacy similar to that of intravenous prostacyclin. Inhaled nitric oxide is widely accepted as a screening agent for active responders to vasodilators and has a similar hemodynamic profile as inhaled iloprost, although the percentage of responders is considerably lower. However, there are unsolved toxicologic questions and practical difficulties concerning the safe long-term application of nitric oxide. Combining inhaled vasodilators with phosphodiesterase inhibitors may prolong the duration of the effects and improve the convenience of inhaled therapy for pulmonary hypertension. Therapeutic approaches in the future may aim at the transforming growth factor beta pathway and at the identification of early stages of the disease to prevent further disease progression.

Medical therapy of pulmonary hypertension. The prostacyclins

Prostacyclin is a substance produced by endothelial cells that induces vasodilation and inhibition of platelet aggregation and of vascular cell migration and proliferation. A dysregulation of the prostacyclin metabolic pathways has been shown in patients with pulmonary arterial hypertension. The clinical use of prostacyclin has been made possible by the synthesis of stable analogues that possesses different pharmacokinetic properties but share similar pharmacodynamic effects. The greatest experience has been collected with intravenous epoprostenol while other compounds like subcutaneous UT-15, inhaled iloprost and oral beraprost are currently in different stages of clinical development. Although favorable results have been reported for each compound, different benefit-to-side effects profiles characterize the various modalities of the administration.

Iatrogenic paradoxical air embolism in pulmonary hypertension

Paradoxical systemic air embolism (PAE) occurring as a complication of right-to-left intracardiac shunting during evaluation and treatment of pulmonary hypertension (PH) has not been previously reported. We report four cases of PH-associated PAE recently encountered at our center. Two patients with PH experienced transient neurologic deficits during agitated-saline contrast echocardiography (ASCE), and a patent foramen ovale was subsequently diagnosed in both patients. Two patients with Eisenmenger's syndrome (ES), while receiving epoprostenol via multilumen catheters, experienced transient neurologic deficits while flushing the unused port of the catheter. No patient experienced permanent neurologic deficits. We conclude that ASCE poses a risk for PAE in patients with PH and clinically silent, previously undetected, right-to-left intracardiac shunts, and that multilumen catheters used for long-term epoprostenol therapy in ES carry a risk of PAE.

One-year continuous inhaled nitric oxide for primary pulmonary hypertension

We describe a case of long-term administration of nitric oxide (NO) in a 32-year-old man who was admitted with exertional dyspnea and anasarca. A diagnosis of primary pulmonary hypertension was made. An acute vasodilator trial with inhaled NO showed a 5% reduction of the mean pulmonary artery pressure. Long-term NO inhalation therapy was initiated. Twenty days later, the dyspnea improved, the anasarca resolved, and the PaO(2) level increased. After 12 months of NO therapy, the patient remained stable and no signs of toxicity or tachyphylaxis were observed. To our knowledge, this is the first report of 1 year of continuously inhaled NO in an adult patient with primary pulmonary hypertension. These findings suggest that prolonged NO therapy might be an effective alternative, at a lower cost, to the continuous IV infusion of epoprostenol.

Comparison of the effects of nitric oxide, nitroprusside, and nifedipine on hemodynamics and right ventricular contractility in patients with chronic pulmonary hypertension

STUDY OBJECTIVES

The effects of inhaled nitric oxide (NO) on hemodynamics and right ventricular (RV) contractility were compared with those of nitroprusside and nifedipine in 14 patients with severe chronic pulmonary hypertension.

STUDY DESIGN

Micromanometer and balloon-tipped right heart catheterization were performed. Inhaled NO, IV nitroprusside, and sublingual nifedipine were administered sequentially while patients breathed > 90% oxygen.

SETTING

Cardiac catheterization laboratory in a tertiary care teaching hospital.

PATIENTS

Fourteen patients with severe pulmonary hypertension unrelated to left ventricular dysfunction.

MEASUREMENTS AND RESULTS

During NO inhalation, mean systemic arterial pressure (MAP) was unchanged, but pulmonary artery (PA) pressure ([mean +/- SEM] 49 +/- 2 mm Hg vs 44 +/- 2 mm Hg; p < 0.01), pulmonary vascular resistance (PVR; 829 +/- 68 vs 669 +/- 64 dyne x s x cm(-5); p < 0.01) and RV end-diastolic pressure (RVEDP; 12 +/- 1 vs 10 +/- 1 mm Hg; p < 0.01) decreased. Stroke volume index (SVI; 31 +/- 2 vs 35 +/- 3 mL/m(2); p < 0.05) increased, and the first derivative of RV pressure at 15 mm Hg developed pressure (RV +dP/dt at DP15) was unchanged. During nitroprusside administration, MAP decreased (105 +/- 5 vs 76 +/- 5 mm Hg; p < 0.01), PA was unchanged (48 +/- 2 vs 45 +/- 3 mm Hg; p = not significant), and PVR decreased (791 +/- 53 vs 665 +/- 53 dyne x s x cm(-5); p < 0.01). RV +dP/dt at DP15 increased (425 +/- 22 vs 465 +/- 29 mm Hg/s; p < 0.05), but SVI was unchanged. Nifedipine decreased MAP (103 +/- 5 vs 94 +/- 5 mm Hg; p < 0.01), PA and PVR were unchanged, RVEDP increased (12 +/- 1 vs 14 +/- 2 mm Hg; p < 0.01), and RV +dP/dt at DP15 decreased (432 +/- 90 vs 389 +/- 21 mm Hg/s; p < 0.05).

CONCLUSIONS

Inhaled NO is a selective pulmonary vasodilator in patients with chronic pulmonary hypertension that improves cardiac performance without altering RV contractility. Nitroprusside caused a similar degree of pulmonary vasodilation. In contrast to inhaled NO, nitroprusside caused systemic hypotension associated with an increase in RV contractility. Acute administration of nifedipine did not cause pulmonary vasodilation, but RVEDP increased and RV contractility decreased.

Hemodynamic effects of epoprostenol in patients with systemic sclerosis and pulmonary hypertension

STUDY OBJECTIVES

To determine the cause of pulmonary hypertension (PH) in systemic sclerosis (SSc) patients since PH can occur because of pulmonary arteriopathy, pulmonary parenchymal destruction, and left ventricular cardiac dysfunction.

DESIGN AND SETTING

Consecutive case series in a university hospital.

PATIENTS

Nine SSc patients with PH (mean pulmonary artery pressure, 41 mm Hg), with (n = 6) or without (n = 3) concomitant interstitial lung disease (ILD).

METHODS

Acute infusion of epoprostenol was begun at 2 ng/kg/min and was titrated upward at a rate of 2 ng/kg/min every 30 min until symptomatic complications developed or pulmonary artery vascular resistance (PVR) was reduced by 50%.

RESULTS

Eight of nine patients demonstrated a reduction of > or = 20% in PVR, suggesting that vasoreactivity is common despite the presence of significant ILD. A single patient had no response to infusion with unchanged hemodynamics and oxygenation. One patient developed hypoxemia as cardiac output increased, suggesting a worsening of ventilation/perfusion matching or the presence of an anatomic shunt. Acute pulmonary edema developed in one patient at an infusion rate of 6 ng/kg/min. The results of cardiac catheterization suggested that pulmonary edema was caused by SSc heart disease.

CONCLUSION

SSc patients with ILD have diverse and sometimes multiple causes of PH that can be determined by short-term epoprostenol infusion. Beneficial effects can be obtained from epoprostenol despite extensive ILD.

Epoprostenol for treatment of pulmonary hypertension in patients with systemic lupus erythematosus

OBJECTIVE

Pulmonary hypertension with pathological changes similar to those observed in primary pulmonary hypertension occurs in patients with systemic lupus erythematosus (SLE). The efficacy of chronic epoprostenol therapy in SLE has not been well described. The objective of this paper is to describe our experience with long-term epoprostenol therapy in patients with pulmonary hypertension associated with SLE.

DESIGN

Case series of six patients with SLE and associated pulmonary hypertension receiving chronic treatment with epoprostenol.

RESULTS

All 6 patients had severe pulmonary hypertension. Mean pulmonary artery pressure (mPAP) was 57 +/- 9 mm Hg (mean +/- SD), and pulmonary vascular resistance was 14 +/- 7 units before beginning therapy with epoprostenol. In 4 patients who underwent repeat hemodynamic evaluation (9 to 16 months after starting epoprostenol), mean pulmonary artery pressure decreased by 38 +/- 21% and pulmonary vascular resistance by 58 +/- 12%. Clinically, all patients improved from New York Heart Association class III or IV to class I or II. Doses of epoprostenol ranged from 4 to 46 ng/kg/min, and the longest duration of therapy has been 2.5 years. Side effects from epoprostenol have not differed from those seen in patients with primary pulmonary hypertension, and except for one patient, there has been no exacerbation of SLE.

CONCLUSION

Epoprostenol was effective for the treatment of pulmonary hypertension in this small group of patients with SLE. Further evaluation of epoprostenol therapy for patients with SLE and other diseases associated with pulmonary hypertension is warranted.