Sildenafil therapy in secondary pulmonary hypertension: Is there benefit in prolonged use?

Pulmonary hypertension in the setting of interstitial lung disease: Approach to management and treatment. A consensus statement from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative-Group 3 Pulmonary Hypertension

Pulmonary hypertension (PH) due to interstitial lung disease (ILD), a commonly encountered complication of fibrotic ILDs, is associated with significant morbidity and mortality. Until recently, the studies of pulmonary vasodilator therapy in PH-ILD have been largely disappointing, with some even demonstrating the potential for harm. This paper is part of a series of Consensus Statements from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative for Group 3 Pulmonary Hypertension, with prior publications covering pathogenesis, prevalence, clinical features, phenotyping, clinical trials, and impact of PH-ILD. It offers a comprehensive review of and a holistic approach to treatment of PH-ILD, including the management of underlying interstitial lung diseases, importance of treating the comorbidities, emphasis on importance of exercise and palliation of dyspnea, and review of the most up-to-date guidelines for referral for potential lung transplant work up. It also summarizes the prior, ongoing, and possibly future studies in treatment of the vascular derangement of this morbid condition.

Pulmonary Hypertension in Interstitial Lung Disease: Management Options to Move Beyond Supportive Care

Purpose of Review

This review delineates current diagnostic and management strategies for pulmonary hypertension due to interstitial lung disease (PH-ILD).

Recent Findings

The INCREASE trial, a phase III multicenter, randomized, placebo-controlled trial demonstrated both improved 6-min walk distance and decreased disease progression with inhaled treprostinil. This pivotal trial led to inhaled treprostinil becoming the first FDA approved medication for treatment of PH-ILD. The availability of this treatment has generated subsequent recommendations for the screening for PH in patients with ILD. As a result, it is becoming increasingly important for clinicians to gain awareness and familiarity with the evolving management options for PH-ILD.

Summary

The management of PH-ILD has its roots in goal-directed treatment of the underlying lung disease. However, recent medication advances and ongoing clinical studies are opening opportunities for more disease-specific treatment.

Combined Pulmonary Fibrosis and Emphysema With Pulmonary Hypertension: Cases Report

BACKGROUND

The combination of pulmonary fibrosis and emphysema (CPFE) has been recently defined as a syndrome, it is radiologically recognized and is characterized by the simultaneous coexistence of emphysema of superior pulmonary location and fibrosis predominantly in lower lobes.

CASE PRESENTATION

We present three patients with CPFE, who underwent right cardiac catheterization for pulmonary hemodynamic assessment, finding mean pulmonary artery pressure (mPAP) between 37-52 mm Hg (mean 45 mm Hg), who received treatment with specific vasodilators for pulmonary arterial hypertension (PAH).

DISCUSSION AND CONCLUSIONS

The three patients had higher mPAP than expected for Group III (Pulmonary hypertension due to lung disease and/or hypoxia) of the classification of pulmonary hypertension (PH) by the World Health Organization (WHO), in whom the use of Sildenafil was justified by the presence of progressive dyspnea, and no symptoms suggestive of infectious exacerbation associated with right ventricular failure.

Therapeutic sildenafil inhibits pulmonary damage induced by cigarette smoke exposure and bacterial inhalation in rats

Context: Clinical reports showed sildenafil beneficial therapy on severe chronic obstructive pulmonary disease (COPD) with pulmonary hypertension (PH) patients.Objective: The study investigated therapeutic effects of silenafil on pulmonary damage induced by cigarette smoke exposure and bacterial inhalation in rats.Materials and methods: Female Sprague-Dawley rats (200-250 g) were divided into control group (no exposure, n = 10) and exposure group (n = 50) suffered from cigarette smoke exposure and Klebsiella pneumonia inhalation for 8 weeks. Then rats were orally given normal saline (control group or model group), 2.0, 3.0, or 4.5 mg/kg sildenafil for 4 weeks, respectively. Pulmonary pressure, RVHI and morphological analysis of pulmonary vascular remodeling, respiratory functions assay, morphological analysis of pulmonary alveoli, and expression of PCNA and caspase-3 of epithelial cells in bronchioles wall were examined.Results: Compared to model rats, 2.0, 3.0, and 4.5 mg/kg sildenafil increased VT by -0.6 to 9.58%, PEF by 3.12 to 6.49%, EF50 by 0.81 to 6.50%, decreased mPAP by 4.43 to 25.58%, RVHI by 6.54 to 26.41%, showing a dose-dependent improvement. Furthermore, 4.5 mg/kg sildenafil significantly increased MAN by 39.70%, LA/CSA by 37.07%, decreased muscular pulmonary arteries by 48.00%, WT by 12.83%, MT by 22.89%, caspase-3 expression by 17.71%, and showed improvement on abnormality in lung interstitial and bronchioles by microscopy.Discussion and conclusion: Our results demonstrated that sildenafil decreased pathological changes in alveoli, bronchioles, interstitial tissue, and arterioles of rats with COPD and PH.

The Trouble With Group 3 Pulmonary Hypertension in Interstitial Lung Disease: Dilemmas in Diagnosis and the Conundrum of Treatment

Pulmonary hypertension (PH) due to interstitial lung disease (ILD; PH-ILD) can complicate a multitude of ILDs, including idiopathic pulmonary fibrosis, chronic hypersensitivity pneumonitis, and nonspecific interstitial pneumonia. Development of PH-ILD is associated with increased need for supplemental oxygen, reduced mobility, and decreased survival. A high index of suspicion is required to make the diagnosis, given the substantial overlap in symptoms with those of ILD without PH. Severely reduced diffusing capacity or 6-min walk test distance, prominent exertional desaturation, and impaired heart rate recovery after exercise are all suggestive of the development of PH-ILD. Traditional transthoracic echocardiography is the most commonly used screening test for PH-ILD, but it lacks sensitivity and specificity. Newer echocardiographic tools involving 3-dimensional assessment of the right ventricle may have a role in both prognosis and the monitoring of patients with PH-ILD. Right-sided heart catheterization remains the gold standard for confirming a diagnosis of PH-ILD. Although there is little debate about the use of supplemental oxygen and diuretic therapy in the treatment of PH-ILD, treatment with pulmonary vasodilator therapy remains controversial. Although several studies have been terminated prematurely for harm, the recently completed INCREASE trial of inhaled treprostinil appears to validate the concept of treating PH-ILD with pulmonary vasodilators and, we hope, will serve as a foundation from which future studies can be developed.

Secondary pulmonary arterial hypertension: to treat or not to treat?

PURPOSE OF REVIEW

The purpose of this review is to review recent literature related to mechanisms and treatment options for 'secondary' (i.e., WHO Groups 3 and 5) pulmonary arterial hypertension (PAH).

RECENT FINDINGS

Published randomized controlled trials, in general, do not support the use of approved therapies for 'primary' (i.e., WHO Group 1) PAH patients in patients with Group 3 PAH because of the small numbers of patients and inconsistent benefit. Therefore, we currently recommend against the use of these medications for Group 3 PAH. Similarly, there is limited evidence supporting the use of Group 1 PAH medications in Group 5 patients. In most patients with Group 5 PAH, treatment should be directed to the underlying disease.

SUMMARY

The utility of PAH-specific therapy in WHO Group 3 PAH is unclear because of the small numbers of patients evaluated and inconsistent beneficial effects observed. There is limited evidence supporting the use of PAH medications in Group 5 patients, and they may be harmful in some cases.

Phosphodiesterase 2 inhibition preferentially promotes NO/guanylyl cyclase/cGMP signaling to reverse the development of heart failure

Heart failure (HF) is a shared manifestation of several cardiovascular pathologies, including hypertension and myocardial infarction, and a limited repertoire of treatment modalities entails that the associated morbidity and mortality remain high. Impaired nitric oxide (NO)/guanylyl cyclase (GC)/cyclic guanosine-3',5'-monophosphate (cGMP) signaling, underpinned, in part, by up-regulation of cyclic nucleotide-hydrolyzing phosphodiesterase (PDE) isozymes, contributes to the pathogenesis of HF, and interventions targeted to enhancing cGMP have proven effective in preclinical models and patients. Numerous PDE isozymes coordinate the regulation of cardiac cGMP in the context of HF; PDE2 expression and activity are up-regulated in experimental and human HF, but a well-defined role for this isoform in pathogenesis has yet to be established, certainly in terms of cGMP signaling. Herein, using a selective pharmacological inhibitor of PDE2, BAY 60-7550, and transgenic mice lacking either NO-sensitive GC-1α (GC-1α^-/-) or natriuretic peptide-responsive GC-A (GC-A^-/-), we demonstrate that the blockade of PDE2 promotes cGMP signaling to offset the pathogenesis of experimental HF (induced by pressure overload or sympathetic hyperactivation), reversing the development of left ventricular hypertrophy, compromised contractility, and cardiac fibrosis. Moreover, we show that this beneficial pharmacodynamic profile is maintained in GC-A^-/- mice but is absent in animals null for GC-1α or treated with a NO synthase inhibitor, revealing that PDE2 inhibition preferentially enhances NO/GC/cGMP signaling in the setting of HF to exert wide-ranging protection to preserve cardiac structure and function. These data substantiate the targeting of PDE2 in HF as a tangible approach to maximize myocardial cGMP signaling and enhancing therapy.

Pulmonary Hypertension in Diffuse Parenchymal Lung Diseases

Pulmonary hypertension (PH) can be triggered by any number of disease processes that result in increased pulmonary vascular resistance. Although historically associated with idiopathic pulmonary arterial hypertension (PAH), most patients with PH do not have the idiopathic subtype, but rather PH associated with another underlying diagnosis, such as left heart or lung disease. The World Health Organization (WHO) classification of PH helps conceptualize the different categories based on presumed etiology. WHO group 3 is PH associated with lung disease. This review focuses on PH in diffuse parenchymal lung diseases (DPLDs), such as the idiopathic interstitial pneumonias and other more rare forms of DPLD. Although there are clear associations of PH with DPLD, the exact pathophysiologic mechanisms and full clinical significance remain uncertain. Treatment of PH related to DPLD remains investigational, but an area of great interest given the negative prognostic implications and the growing number of available pulmonary vasoactive agents.

Pulmonary hypertension and idiopathic pulmonary fibrosis: a dastardly duo

Pulmonary hypertension (PH) is a well-recognized complication of interstitial lung disease, including idiopathic pulmonary fibrosis (IPF). The underlying pathogenesis was initially hypothesized to be inflammatory but now is characterized as an over exuberant fibroproliferative process. The prevalence of PH in the setting of IPF has not been well described in the literature, with a reported occurrence from 32% to 85%. Diagnostically, recognizing underlying PH in the setting of IPF remains challenging because of nonspecific clinical symptoms and unrevealing ancillary testing. A high degree of clinical suspicion is paramount. The only reliable diagnostic tool for PH is right heart catheterization. The treatment of PH, in patients with IPF, is based on multiple factors, including disease severity, functional status and degree of hypoxemia. Medications currently approved to treat PH have been administered for PH in the setting of IPF, such as phosphodiesterase-5 inhibitors, nonselective endothelin receptor antagonists and prostacyclin analogues. The treatment of PH in the setting of IPF may also be difficult due to worsening ventilation-perfusion mismatch induced by selective pulmonary artery vasodilator therapy. Lung transplantation should be considered with patients refractory to pharmacological treatment. Identification of PH in IPF patients is crucial, as functional status and prognosis are greatly reduced. Given the high mortality rate and propensity for acute decompensation, IPF and PH patients should be evaluated for transplant early in their disease course.

Udenafil improves exercise capacity in patients with chronic obstructive pulmonary disease: a prospective study

Pulmonary hypertension (PH) is a serious complication of chronic obstructive pulmonary disease (COPD), and there is no effective pharmacological treatment for COPD-associated PH. We evaluated the effect of udenafil, a phosphodiesterase-5 (PDE-5) inhibitor, on the exercise capacity of patients with severe COPD. Patients with severe and very severe COPD (forced expiratory volume in one second (FEV(1)) <50% of predicted) received udenafil (50 mg daily) for 8 weeks. A 6-min walk test (6MWT), lung function test, Doppler echocardiography, and Saint George's Respiratory Questionnaire (SGRQ) were completed before and after therapy. The primary outcome was a change in the 6-min walk distance (6MWD). Thirty-eight patients were screened for eligibility, and 23 completed the study. After 8 weeks of udenafil treatment, the mean 6MWD increased from 315 to 348 m (p = 0.02), and median PASP decreased from 36 to 30 mmHg (p = 0.02). There were no changes in the SGRQ score, Borg dyspnea score, or pulmonary function parameters. The PDE-5 inhibitor udenafil improved exercise capacity and decreased pulmonary artery pressure in patients with severe COPD. However, due to the small sample size, uncontrolled design and high dropout rate, the efficacy of udenafil in severe COPD needs to be confirmed in a large-scale randomized controlled study. This study was registered at ClinicalTrials.gov (number: NCT01364181).

Pulmonary hypertension in idiopathic pulmonary fibrosis: a review

Idiopathic pulmonary fibrosis (IPF) is a progressive diffuse parenchymal disease with a poor prognosis. Pulmonary hypertension (PH) often complicates the course of IPF and may even be found in patients with preserved lung function. Possible pathogenetic mechanisms of PH in IPF include vascular destruction, pulmonary hypoxic vasoconstriction and vascular remodeling due to overexpression of cytokines and growth factors. PH in IPF patients is associated with decreased exercise capacity and a worse prognosis. Due to its prognostic significance, it seems important to investigate for PH in these patients. As the symptoms of PH in IPF are nonspecific, the development of PH in a patient with known IPF can be easily overlooked. Noninvasive methods provide clues for the diagnosis, but their sensitivity is limited. Doppler echocardiography is a useful tool for the detection of PH which also provides additional information regarding associated cardiac abnormalities. However, right heart catheterization remains the gold standard diagnostic test. Therapeutic options for PH in IPF are limited. Long-term oxygen administration for the correction of hypoxemia should be recommended. The availability of new pharmacological agents in the treatment of PH has raised the possibility of therapy in patients with IPF and associated PH. Whether these PH-targeted therapies may be of benefit in this patient group, in terms of improving functional outcomes and survival, remains uncertain.

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension is one of the few forms of pulmonary hypertension that is surgically curable. It is likely underdiagnosed and must be considered in every patient presenting with pulmonary hypertension to avoid missing the opportunity to cure these patients. This article discusses the epidemiology, risk factors, natural history, diagnosis, and preoperative evaluation of patients with this disorder. Also covered are putative mechanisms for the conversion of acute emboli into fibrosed thrombembolic residua. Mechanical obstruction of the central pulmonary vasculature is rarely the sole cause of the pulmonary hypertension, and a discussion of the small vessel arteriopathy present in these patients is offered. Technical aspects of pulmonary endartectomy and the data supporting its role are discussed, as are the limited data on pulmonary arterial hypertension specific medical therapies for patients deemed noncandidates for the operation.

Phosphodiesterase-5 inhibitors in management of pulmonary hypertension: safety, tolerability, and efficacy

Pulmonary arterial hypertension (PAH) is a progressive disease that causes severe disability and has no cure. Over the past 20 years, a variety of treatment options have evolved for the management of PAH. With an expanded therapeutic armamentarium come more complex decisions regarding treatment options. Agent selection depends upon several factors including efficacy, side effect profile, and cost, as well as convenience of administration. We have undertaken a review of phosphodiesterase-5 (PDE-5) inhibitors in PAH with a focus on efficacy and safety. A literature search was conducted using the Medline and Cochrane Central Register of Controlled Trials databases (1966-February 2010) for relevant randomized clinical studies. Overall, 10 studies met our inclusion criteria. Sildenafil was the most commonly studied agent, followed by tadalafil and vardenafil. Most trials found that the PDE-5 inhibitors significantly improved exercise capacity and lowered pulmonary pressures. However, there were conflicting results regarding these agents' impact on improving cardiac function and functional class. Overall, these medications were effective and well tolerated with a relatively benign side effect profile. The PDE-5 inhibitors are an important option in treating PAH. While most of the published clinical data involved sildenafil, the other PDE-5 inhibitors show promise as well. Further studies are needed to determine the optimal doses of this therapeutic drug class, as well as its effects as adjunctive therapy with other agents in PAH.