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Ongoing and Completed Clinical Trials in Pulmonary Hypertension Are Driving the Need for New Practice Guidelines: Presented at CHEST

By Amanda Strong

MONTREAL, CANADA -- November 4, 2005 -- It's been only a year since the last revision of the evidence-based practice guidelines for the diagnosis and management of pulmonary hypertension, but already much has changed.

"Because treatments have been evolving, we will be updating the treatment algorithm very soon," said Lewis J. Rubin, MD, professor of medicine, division of pulmonary and critical care medicine, University of California, San Diego, La Jolla, California, United States.

Dr. Rubin is chair of the international panel of experts who developed the guidelines. He said an update to the medical therapy section of the guidelines is expected to be available mid-2006.

"There is a recognized need to update those guidelines," echoed copresenter David S. Badesch, MD, professor of medicine, and clinical director of pulmonary hypertension center, division of pulmonary sciences and critical care medicine, University of Colorado Health Sciences Centre, Denver, Colorado, United States, in an interview. "It's an exciting field."

The 2 physicians discussed the current and anticipated changes to the guidelines here on November 2^nd at the American College of Chest Physicians Annual Meeting (CHEST).

In terms of treatment strategies, the current recommendations for patients with New York Heart Association (NYHA) functional class II and III are now outdated, Dr. Badesch said, and pointed to new data coming out of clinical trials driving the need to update this section of the current guidelines.

Current guidelines for NYHA class II or III recommend that patients who are not candidates for, or who have failed, calcium channel blocker (CCB) therapy might benefit from long-term therapy with endothelin-receptor antagonists (bosentan), IV epoprostenol, subcutaneous treprostinil, inhaled iloprost, or beraprost. IV treprostinil became available and was approved for use after the last set of guidelines were released, so this agent can also be added to the list of available treatment options.

The vasodilator epoprostenol remains the treatment of choice for patients with NYHA functional class IV. Sildenafil is currently recommended in patients with pulmonary hypertension who have failed or are not candidates for other available therapy, although this may change.

Combination therapy is a hot topic in the treatment of pulmonary hypertension, and information about combination therapy will hopefully be included in the revised guidelines, Dr. Rubin said during the session's question period. Several studies have looked at combining various available agents, and a number of other studies are being planned.

Proven combinations are bosentan and inhaled iloprost, evaluated in the STEP study (iloprost inhalation solution Safety and pilot efficacy Trial in combination with bosentan for Evaluation in Pulmonary arterial hypertension), as well as bosentan with epoprostenol, evaluated in 2 smaller studies.

Ongoing trials include a relatively large one looking at sildenafil in patients on stable epoprostenol, Dr. Rubin said. "There are a lot of unknowns at this point about the various combinations," he said.

In terms of diagnosis, exertional dyspnea is the most commonly presenting symptom of pulmonary hypertension. Fatigue, weakness, or complaints of general exertion intolerance are also common complaints.

Echocardiography is often the first test that is performed in patients suspected of having pulmonary hypertension, but it should not be the last, Dr. Rubin said during his presentation. The standard test, echocardiography, should be combined with a chest x-ray and pulmonary function test. Sleep study is not required but should be performed when there is a strong suspicion of sleep disorder, he said.

For diagnosis of chronic thromboembolic pulmonary hypertension, the ventilation-perfusion scan is the test of choice, and while computer tomography (CT) angiograms are also in the guidelines, they are not sufficient to exclude this condition.

An HIV test should also be performed for all patients with pulmonary hypertension, since sometimes HIV infection can present as pulmonary hypertension. Liver function tests should also be performed.

In approaching the diagnosis of unexplained pulmonary hypertension, the guidelines recommend that appropriate imaging studies should be performed to look for evidence of peripheral airways disease, such as a high resolution CT scan of the chest.

Based on the guidelines, Dr. Rubin recommends that specialists look particularly for disconnects such as haemodynamics that are out of proportion to gas exchange or lung function that might be clues to a diagnosis of pulmonary hypertension. He also advises to consider coexisting conditions, and to work through the diagnostic algorithm regardless of where in the patient's course the specialist is asked to intervene.

Dr. Rubin said he feels strongly about the role of the internist or local physician in patient management. "It's critical that the specialist and internist share responsibility," he said in an interview. "There are important roles in the day-to-day oversight and management that the internist, the GP, or the local physician has in concert with the specialist."

Citation: Treatment Guidelines: Rubin L and the American College of Chest Physicians. Diagnosis and management of pulmonary arterial hypertension: ACCP evidence-based clinical practice guidelines. Chest. 2004 Jul;126(1 Suppl).


[Presentation title: Pulmonary Hypertension]

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