Management of pulmonary hypertension resulting from interstitial lung disease

The impact of FVC/DLCO ratio on diagnosis of pulmonary hypertension and disease prognosis in idiopathic pulmonary fibrosis

Introduction: Idiopathic pulmonary fibrosis is a chronic progressive fibrotic lung disease of unknown etiology that occurs most commonly in older adults. The presence of pulmonary hypertension in Idiopathic pulmonary fibrosis is associated with poor prognosis and mortality. Literature suggests that the forced vital capacity to diffusion capacity of the lung for carbon monoxide ratio has a positive predictive value for the diagnosis of pulmonary hypertension. Therefore, this study aimed to investigate the impact of forced vital capacity to diffusion capacity of the lung for carbon monoxide ratio on the diagnosis of pulmonary hypertension and disease prognosis in Idiopathic pulmonary fibrosis patients. MATERIAL AND METHOD: Forty-eight patients diagnosed with Idiopathic pulmonary fibrosis were included in the study. Patient records, echocardiographic and spirometric data were retrospectively reviewed. Results: The average pulmonary arterial pressure was observed to be 32.8 (±9) mmHg, with the second-year follow-up pulmonary arterial pressure at 40.8 (±17.2) mmHg and the fourth-year follow-up pulmonary arterial pressure at 51 (±23.6) mmHg. In those diagnosed as pulmonary hypertension, the forced vital capacity to diffusion capacity of the lung for carbon monoxide ratio was initially 1.54 (±0.72). By the second year, it was 1.61 (±0.45), and by the fourth year, it was 1.87 (±0.8). It was found that the forced vital capacity to diffusion capacity of the lung for carbon monoxide ratio tended to increase when pulmonary artery pressure increased during the follow-up period. Conclusion: We found that low six- minute walking test distance was an important marker for the diagnosis of pulmonary hypertension in patients with idiopathic pulmonary fibrosis and that the presence of desaturation was also significantly associated with survival in pulmonary hypertension. Although we did not find it statistically significant, we found that both pulmonary arterial pressure and the the forced vital capacity to diffusion capacity of the lung for carbon monoxide ratio increased with progressive disease duration after diagnosis in patients with IPF. We believe that the the forced vital capacity to diffusion capacity of the lung for carbon monoxide ratio is an important marker for early detection of pulmonary hypertension and prognosis in idiopathic pulmonary fibrosis.

Management of connective tissue disease-associated interstitial lung disease

A thorough, often multidisciplinary assessment to determine extrathoracic versus intrathoracic disease activity and degrees of impairment is needed to optimize the management of connective tissue disease (CTD)-associated interstitial lung disease (ILD). Pharmacologic intervention with immunosuppression is the mainstay of therapy for all forms of CTD-ILD, but should be reserved for those that show clinically significant and/or progressive disease. The management of CTD-ILD is not yet evidence based and there is a need for controlled trials across the spectrum of CTD-ILD. Nonpharmacologic management strategies and addressing comorbidities or aggravating factors should be included in the comprehensive treatment plan for CTD-ILD.

Pulmonary hypertension secondary to interstitial lung disease

Interstitial lung diseases (ILDs) may be complicated by the development of pulmonary hypertension (PH), which is associated with worse functional impairment and a poorer prognosis. This article reviews the current state of knowledge on the prevalence, pathogenesis, diagnosis and prognosis of ILD-related PH. Whether the treatment of ILD-related PH changes clinical outcomes is currently unknown, but the current studies are summarized and the authors' perspective is offered.

Evaluation of recently validated non- invasive formula using basic lung functions as new screening tool for pulmonary hypertension in idiopathic pulmonary fibrosis patients

BACKGROUND:

A prediction formula for mean pulmonary artery pressure (MPAP) using standard lung function measurement has been recently validated to screen for pulmonary hypertension (PH) in idiopathic pulmonary fibrosis (IPF) patients.

OBJECTIVE:

To test the usefulness of this formula as a new non invasive screening tool for PH in IPF patients. Also, to study its correlation with patients' clinical data, pulmonary function tests, arterial blood gases (ABGs) and other commonly used screening methods for PH including electrocardiogram (ECG), chest X ray (CXR), trans-thoracic echocardiography (TTE) and computerized tomography pulmonary angiography (CTPA).

MATERIALS AND METHODS:

Cross-sectional study of 37 IPF patients from tertiary hospital. The accuracy of MPAP estimation was assessed by examining the correlation between the predicted MPAP using the formula and PH diagnosed by other screening tools and patients' clinical signs of PH.

RESULTS:

There was no statistically significant difference in the prediction of PH using cut off point of 21 or 25 mm Hg (P = 0.24). The formula-predicted MPAP greater than 25 mm Hg strongly correlated in the expected direction with O₂ saturation (r = −0.95, P < 0.000), partial arterial O₂ tension (r = −0.71, P < 0.000), right ventricular systolic pressure measured by TTE (r = 0.6, P < 0.000) and hilar width on CXR (r = 0.31, P = 0.03). Chest symptoms, ECG and CTPA signs of PH poorly correlated with the same formula (P > 0.05).

CONCLUSIONS:

The prediction formula for MPAP using standard lung function measurements is a simple non invasive tool that can be used as TTE to screen for PH in IPF patients and select those who need right heart catheterization.

Endothelin: 20 years from discovery to therapy

Since its identification as an endothelial cell-derived vasoconstrictor peptide in 1988, endothelin-1, the predominant member of the endothelin peptide family, has received considerable interest in basic medical science and in clinical medicine, which is reflected by more than 20 000 scientific publications on endothelin research in the past 20 years. The story of endothelin is unique as the gene sequences of endothelin receptors and the first receptor antagonists became available within only 4 years of the identification of the peptide sequence. The first clinical study in patients with congestive heart failure was published only 3 years thereafter. Yet, despite convincing experimental evidence of a pathogenetic role for endothelin in development, cell function, and disease, many initial clinical studies on endothelin antagonism were negative. In many of these studies, study designs or patient selection were inadequate. Today, for diseases such as pulmonary hypertension, endothelin antagonist treatment has become reality in clinical medicine, and ongoing clinical studies are evaluating additional indications, such as renal disease and cancer. Twenty years after the discovery of endothelin, its inhibitors have finally arrived in the clinical arena and are now providing us with new options to treat disease and prolong the lives of patients. Possible future indications include resistant arterial hypertension, proteinuric renal disease, cancer, and connective tissue diseases.

Pulmonary hypertension in older adults

Pulmonary hypertension is a frequently encountered problem in older patients. True idiopathic pulmonary arterial hypertension can also be seen and requires careful exclusion in older patients. Institution of therapies must be tempered with an appreciation of individual comorbidities and functional limitations that may affect patients' ability to comply and benefit from the complex treatments available for pulmonary arterial hypertension. This article reviews the existing data on the various forms of pulmonary hypertension presenting in older patients and on appropriate therapy in this challenging population.

Does Sildenafil produce a sustained benefit in patients with pulmonary hypertension associated with parenchymal lung and cardiac disease?

BACKGROUND

Sildenafil may be of benefit for selected patients with pulmonary hypertension associated with parenchymal lung and cardiac diseases. However the medium term benefits of this treatment for such patients is unclear.

PATIENTS AND METHODS

16 consecutive patients with secondary pulmonary hypertension who had been on maximal appropriate therapy received Sildenafil 50 mg tds following assessment which included right heart catheter, 2D echocardiography and six minute walk test. Right heart catheterisation, 2D echocardiography and six minute walk test were performed after eight weeks treatment, at 12 months and at six monthly intervals thereafter. Baseline medications were continued.

RESULTS

16 patients with pulmonary hypertension associated with inoperable chronic pulmonary thromboembolism (6 patients), valvular heart disease (4), chronic obstructive pulmonary disease (3), idiopathic pulmonary fibrosis (2), and obstructive sleep apnoea (1) were studied. The age range was 42 to 81 (median 68) years and the period of follow up was 12 to 51 (median 22) months. Six minute walk increased significantly, p=0.002, from baseline to long term follow up. The improvement in 14 patients ranged from 14 m to 300 m with a percentage increase of 5% to 567% increase. In one patient there was no change and in one patient the six minute walk test fell as a consequence of progression of known arthritis. The mean pulmonary artery pressure was significantly reduced at long term follow up (p=0008). The pulmonary vascular resistance (PVR) fell in eleven patients, this reduction ranged from 0.2 woods units to 8.7 woods units (mean reduction 3.3 woods units). The percentage reduction in PVR ranged from 7% to 71% with a mean reduction of 43%. In five patients the pulmonary vascular resistance increased. 2D echocardiography showed a sustained improvement in right ventricular function in 11 patients. There were no deaths during follow up.

CONCLUSION

Sildenafil may have a role for selected patients with pulmonary hypertension associated with cardiac and pulmonary diseases. The medication seems well tolerated and for some patients is effective within 8 weeks and results in a sustained long term improvement in haemodynamics and exercise capacity.

Pulmonary hypertension in patients with interstitial lung diseases

Pulmonary hypertension (PH) in patients with interstitial lung diseases (ILDs) is not well recognized and can occur in the absence of advanced pulmonary dysfunction or hypoxemia. To address this topic, we identified relevant studies in the English language by searching the MEDLINE database (1966 to November 2006) and by individually reviewing the references of identified articles. Connective tissue disease-related ILD, sarcoidosis, idiopathic pulmonary fibrosis, and pulmonary Langerhans cell histiocytosis are the ILDs most commonly associated with PH. Pulmonary hypertension is an underrecognized complication in patients with ILDs and can adversely affect symptoms, functional capacity, and survival. Pulmonary hypertension can arise in patients with ILDs through various mechanisms, Including pulmonary vasoconstriction and vascular remodeling, vascular destruction associated with progressive parenchymal fibrosis, vascular inflammation, perivascular fibrosis, and thrombotic angiopathy. Diagnosis of PH in these patients requires a high index of suspicion because the clinical presentation tends to be nonspecific, particularly in the presence of an underlying parenchymal lung disease. Doppler echocardiography is an essential tool in the evaluation of suspected PH and allows ready recognition of cardiac causes. Right heart catheterization is needed to confirm the presence of PH, assess its severity, and guide therapy. Management of PH in patients with ILDs is guided by identification of the underlying mechanism and the clinical context. An increasing number of available pharmacologic agents in the treatment of PH allow possible treatment of PH in some patients with ILDs. Whether specific treatment of PH in these patients favorably alters functional capacity or outcome needs to be determined.

A potential role for sildenafil in the management of pulmonary hypertension in patients with parenchymal lung disease

BACKGROUND

Sildenafil offers potential to treat patients with pulmonary hypertension by selectively inhibiting phosphodiesterase type five pathways in the lung. It is recommended for selected patients with pulmonary arterial hypertension, but its role in the management of pulmonary hypertension associated with parenchymal lung disease is unclear.

PATIENTS AND METHODS

Seven patients (68-86 years) with end stage chronic obstructive pulmonary disease (COPD, 4) and idiopathic pulmonary fibrosis (IPF, 3) were referred to our unit. All patients had a long-term history of chronic lung disease and were on maximal appropriate therapy prescribed by their referring pulmonologist. Thromboembolic disease was excluded by pulmonary angiography and all patients had had high resolution thoracic CT scan. At assessment right heart catheterisation, 2D echocardiography and 6-min walk test were performed prior to commencement of sildenafil 50mg tds. Their medication was otherwise unchanged. After 8 weeks treatment, right heart catheterisation, 2D echocardiography and 6-min walk test were repeated.

RESULTS

The pulmonary vascular resistance was reduced in six patients (from 13, 3, 3, 6.5, 3.5 and 10.5 wood units to 9.7, 2.5, 2.8, 4.4, 2.5 and 5.4 wood units, respectively). Six-minute walk test increased in six patients (from 110 m, 210 m, 80 m, 30 m, 210 m and 80 m to 130 m, 312 m, 120 m, 82 m, 244 m and 100 m, respectively). One patient with COPD did not demonstrate a favourable response although their cardiac output increased on sildenafil therapy. 2D echocardiography showed a reduction in estimated PA pressure in six patients with an improvement in right ventricular systolic function in two COPD patients.

CONCLUSION

Our results suggest that sildenafil may have a role for selected patients with COPD and IPF who have pulmonary hypertension.

Pulmonary hypertension in patients with idiopathic pulmonary fibrosis

STUDY OBJECTIVES

To determine the impact on survival and clinical correlates of pulmonary hypertension (PH) occurring in patients with idiopathic pulmonary fibrosis (IPF).

DESIGN

Retrospective study.

SETTING

Tertiary care, referral medical center.

PATIENTS

Among 487 consecutive patients with IPF, we identified 136 patients who underwent transthoracic echocardiography within 3 months of their initial evaluation at our institution. Patients with left ventricular dysfunction, valvular heart disease, incomplete follow-up, and those in whom pulmonary artery pressures could not be assessed were excluded; the remaining 88 patients were included in this study. Correlations were performed between echocardiographic measures of PH and clinical variables including survival.

MEASUREMENTS AND RESULTS

The mean (+/- SD) estimated systolic pulmonary artery pressure (SPAP) for the 88 patients was 48 +/- 16 mm Hg (range, 28 to 116 mm Hg). Among pulmonary function parameters, SPAP correlated best with diffusing capacity of the lung for carbon monoxide (D(LCO)), to which it was inversely related. For survival analysis, patients were stratified into three groups: < or = 35 mm Hg (14 patients), 36 to 50 mm Hg (47 patients), and > 50 mm Hg (27 patients). Using the Kaplan-Meier method, the median survival rates for these three groups were 4.8 years, 4.1 years, and 0.7 years, respectively. Those patients with SPAP > 50 mm Hg had significantly worse survival compared to other subgroups (p = 0.009).

CONCLUSION

In patients with IPF, PH correlates inversely with D(LCO) and has a significant adverse impact on survival, particularly when SPAP is > 50 mm Hg.

Lung transplantation and interstitial lung disease

PURPOSE OF REVIEW

Interstitial lung disease includes a heterogeneous group of disorders that leads to respiratory insufficiency and death in a significant number of patients. Lung transplantation is a therapeutic option in select candidates.

RECENT FINDINGS

The indications, transplant procedure options, and outcomes continue to evolve. Various recipient comorbidities influence the choice of procedure in patients with interstitial lung disease. Single lung transplants are used as the procedure of choice and bilateral transplants are reserved for patients with suppurative lung disease and patients with pulmonary hypertension. Issues unique to patients with interstitial lung disease affect the morbidity, mortality and recurrence of the disease.

SUMMARY

Lung transplantation is an effective therapy for respiratory failure in interstitial lung disease with survival following transplant being similar to that achieved in transplant recipients with other diseases.

Lung transplantation for interstitial lung disease

Lung transplantation remains the only therapeutic option shown to improve survival for many end-stage interstitial lung diseases. Although idiopathic pulmonary fibrosis is the most common indication, transplantation has been performed for many other diseases. This article reviews the current indications and outcomes for the procedure and problems encountered in lung transplantation for interstitial lung diseases. The role of transplant for specific diseases also is discussed.

Sildenafil: Emerging Cardiovascular Indications

The discovery in 1989 of sildenafil, a highly selective inhibitor of phosphodiesterase-5 (PDE-5), was the result of extensive research on chemical agents targeting PDE-5 that might potentially be useful in the treatment of coronary heart disease. Initial clinical studies on sildenafil in the early 1990s were not promising with respect to its antianginal potential. However, the incidental discovery of its antiimpotence effect led to its approval of for the treatment of erectile dysfunction. Thereafter, several reports of adverse cardiac events in patients on sildenafil raised concerns about its safety in cardiovascular disorders. Novel therapeutic indications are emerging for sildenafil with the recent discovery that PDE-5 is expressed in various other tissues such as the arterial vasculature, including pulmonary and coronary arteries, venous vasculature, skeletal muscles, platelets, and visceral and tracheobronchial muscles. In this review we briefly summarize the pharmacology of sildenafil and the current available evidence on its potential therapeutic applications in cardiovascular disorders.

Advances in the treatment of rheumatic interstitial lung disease

PURPOSE OF REVIEW

Interstitial lung disease frequently complicates the rheumatic diseases. The purpose of this review is to outline recent advances and current concepts regarding the management of these interstitial lung diseases.

RECENT FINDINGS

Several histologic lesions cause interstitial lung disease in rheumatic diseases, including nonspecific interstitial pneumonia, usual interstitial pneumonia, organizing pneumonia, lymphocytic interstitial pneumonia, desquamative interstitial pneumonia, and acute interstitial pneumonia. Although the relative frequency of occurrence of these histopathologic lesions is not definitively established, it seems that nonspecific interstitial pneumonia accounts for a large proportion of rheumatic disease-associated interstitial lung diseases. Although usual interstitial pneumonia generally responds poorly to corticosteroid therapy, other forms of interstitial pneumonia are often steroid responsive and have a more favorable long-term prognosis. Pulmonary hypertension is increasingly recognized as a complication of these interstitial lung diseases. Treatment of pulmonary hypertension in these patients provides clinical benefit and may suppress pulmonary inflammation and fibrosis. Lung transplantation is a treatment option for selected patients with severe pulmonary involvement and limited life expectancy.

SUMMARY

Interstitial lung disease is common in the rheumatic diseases, may be caused by a variety of lesions that respond differently to treatment, and may lead to the development of pulmonary hypertension. Whether the prognosis of interstitial lung disease associated with rheumatic disease is similar to that associated with the idiopathic interstitial pneumonias is not known. Treatment of these interstitial lung diseases should take into account the specific histologic lesion, the activity of the underlying rheumatic disease, and associated pulmonary hypertension, if present. The diagnosis of a rheumatic disease is no longer an absolute contraindication to lung transplantation.