ProBNP may help determine who should have echocardiograph

March 27, 2007

Natriuretic peptides are useful in the emergency setting to distinguish between acute pulmonary and cardiac causes of dyspnea. Additionally, results of the Copenhagen City Heart Study indicate that pro-B-type natriuretic peptide (proBNP) may be a useful screening tool in nonemergency settings, reported Rasmus Mogelvang, MD, during the American College of Cardiology's 56th annual scientific session.

Natriuretic peptides are useful in the emergency setting to distinguish between acute pulmonary and cardiac causes of dyspnea. Additionally, results of the Copenhagen City Heart Study indicate that pro-B-type natriuretic peptide (proBNP) may be a useful screening tool in nonemergency settings, reported Rasmus Mogelvang, MD, during the American College of Cardiology's 56th annual scientific session.

Dyspnea is a common symptom patients present to primary care physicians on a nonemergency basis, said Dr. Mogelvang, MD, University of Copenhagen, Denmark. "ProBNP is markedly elevated with left ventricular dilatation or hypertrophy, and with left systolic dysfunction and diastolic dysfunction while it remains unaffected by pulmonary status."

The study screened 2,929 general population participants and identified 959 patients reporting dyspnea of unknown etiology. They were evaluated with spirometry, oxygen saturation measurements, echocardiography, and proBNP testing. The researchers found that proBNP levels were significantly elevated by a median of 2.6-fold among patients found to have cardiac conditions compared with those without cardiac conditions.

Dr. Mogelvang said that since proBNP increases with age and is generally higher in women, after adjusting for age and gender researchers established a model to estimate the expected level of proBNP for men and women according to age. For example, a 20-year old male would have an expected proBNP of 4 pmol/L while an 80-year-old woman would have an expected proBNP of 33 pmol/L.

"If proBNP levels are higher than expected for a patient's age and gender then cardiac dysfunction can be suspected and the patient can then be referred for echocardiography," Dr. Movelvang said. Patients with dyspnea but expected proBNP levels should be pursued for a pulmonary diagnosis first, he added.

In addition, a proBNP measurement that is below half of the expected value for a patient's age and gender was found to rule out left ventricular systolic and diastolic dysfunction with 100% sensitivity and 15% specificity, Dr. Movelvang said.