Hormone brain natriuretic peptide can predict pulmonary hypertension

Measuring levels of a hormone called brain natriuretic peptide in individuals with serious lung disease can predict the presence of pulmonary hypertension and a patient's potential death or survival, regardless of clinical severity or the cause of illness.

These results appear in the first issue for April 2006 of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.

Juergen Behr, M.D., of the Division of Pulmonary Diseases in the Department of Internal Medicine at Ludwig Maximillians University in Munich, Germany, and six associates studied brain natriuretic peptide (BNP) in the circulation of 176 consecutive adult patients with a variety of pulmonary diseases. These patients also underwent right heart catheterization, lung function testing, and a 6-minute walk test.

BNP, a hormone produced by the heart, is activated by different cardiovascular diseases. Normally, the level of BNP in the blood is low. However, if the heart has to work harder over a longer period of time due to disease, the level of BNP rises.

The investigators noted that the purpose of their research was to uncover a safe, easy-to-perform method of identifying patients with increased probability of clinically significant pulmonary hypertension.

"In the absence of significant left heart disease, BNP serves as a marker of an increased workload in the right heart originating from idiopathic pulmonary arterial hypertension," Dr. Behr said.

During the 10 months following the study, 31 participants (18 percent) died of cardiopulmonary causes. "Patients who died during the follow-up period more frequently had elevated BNP levels and prominent pulmonary hypertension with significantly impaired right heart function," Dr. Behr continued.

The authors identified a pulmonary artery pressure greater than 35 mm Hg as a degree of significant pulmonary hypertension. Such measurements led to decreased 6-minute walk test distances and increased mortality. More than one-fourth of the patients in the study cohort showed pulmonary hypertension readings above that level.

"Despite the mixed nature of the study population, our data allows an estimation of the prevalence of pulmonary hypertension in a 'real life' setting of patients with advanced lung disease, because all participants underwent right heart catheterization as the reference diagnostic tool," said Dr. Behr.

The investigators concluded that BNP is a prognostic marker and a screening parameter for significant pulmonary hypertension in chronic lung disease.