Researchers have developed a simple, noninvasive way to measure right ventricular function in the heart to predict survival of adults who suffer from pulmonary hypertension. The research appears in the first issue for November 2006 of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.
Paul M. Hassoun, M.D., of the Divisions of Cardiology, Pulmonary and Critical Care Medicine at Johns Hopkins Hospital in Baltimore, and 11 associates studied 63 consecutive patients with pulmonary hypertension. After right heart catheterization, these patients underwent a transthoracic echocardiogram to assess right ventricular performance in the heart.
Study participants were mostly female, white and had an average age of 55. Seventy-five percent (47 patients) met the World Health Organization’s group 1 diagnostic classification of pulmonary hypertension.
In medicine, pulmonary hypertension (PH) is an increase in blood pressure in the pulmonary artery or lung vasculature, leading to shortness of breath, dizziness, fainting, and other symptoms, all of which are exacerbated by exertion. Depending on the cause, pulmonary hypertension can be a severe disease with a markedly decreased exercise tolerance and right-sided heart failure. It was first identified by Dr Ernst von Romberg in 1891. It can be one of five different types, arterial, venous, hypoxic, thromboembolic, or miscellaneous.
Pulmonary hypertension involves progressive narrowing of the blood vessels in the lungs, which can lead to death. In 2000, 163,000 patients discharged from U.S. hospitals had been diagnosed with primary pulmonary hypertension. Although the problem is difficult to detect in a routine medical exam, doctors see more rapid clinical deterioration in patients who have the greatest degree of right ventricular dysfunction.
To assess the problem, researchers performed a test called tricuspid annular plane systolic excursion (TAPSE), which measures echocardiographic abnormalities in the tricuspid valve. Located between the heart’s right atrium and right ventricle, the valve prevents the backflow of blood as it is pumped from the right atrium to the right ventricle.
“We found that a TAPSE of less than 1.8 cm was associated with a greater ventricular systolic dysfunction, as well as right heart remodeling,” said Dr. Hassoun. “In addition, survival estimates at one and two years for those with pulmonary arterial hypertension were 94 percent and 88 percent, respectively, for individuals with a TAPSE of 1.8 cm or greater. If the TAPSE was less, the survival rates were 60 percent at one year and 50 percent at two years.”
The researchers said that patients with a TAPSE of less than 1.8 cm, showing more advanced right ventricular dysfunction, had a dramatically reduced survival rate over the average follow-up time of 19 months. Patients with a TAPSE of less than 1.5 cm had an especially poor outcome.