Tracking Long-term Changes in PAH Patients’ Heart Conditions Could Help Reduce Deaths, Study Suggests

Tracking long-term changes in measurements associated with pulmonary hypertension patients’ death from heart disease can help doctors do a better job of identifying those at higher risk of such deaths, a study reports.

The hallmark of what doctors call pulmonary arterial hypertension due to congenital heart disease, or PAH-CHD, is increased pulmonary vascular resistance. This occurs when the pulmonary artery, which carries deoxygenated blood from the heart to the lungs, creates resistance against the blood flowing into it from the right ventricle, or heart chamber.

PAH-CHD can lead to remodeling of tissue in the ventricles, which collect and expel blood. In severe cases, PAH-CHD can lead to heart failure and death.

This means that the sooner doctors can identify those at higher risk of death from PAH-CHD, the sooner they can prescribe treatments that can prevent death.

Current guidelines recommend that doctors evaluate PAH-CHD patients twice a year with heart-function, biochemical, and heart-imaging measurements. They use those measurements to develop mortality-risk profiles.

Researchers have not studied the prognostic value of long-term changes in the measurements, however.

So a team decided to do just that. Their study, in the International Journal of Cardiology, was titled “Mortality in pulmonary arterial hypertension due to congenital heart disease: Serial changes improve prognostication.”

“This study was the first to extensively investigate the prognostic value of serial changes [changes over time] in standard clinical parameters in PAH-CHD,” the team wrote.

The study included 92 adults with CHD whom doctors treated for PAH.

Thirty-five, or 38 percent, of the patients died during the average follow-up time of six years. About 57 percent of the deaths were from right-side heart failure, 11 percent from sudden cardiac failure, 15 percent from infections, and 3 percent from stroke. About 14 percent of the deaths were from unknown causes.

Researchers discovered that long-term changes in a number of measurements were better predictors of a PAH patient dying of heart failure than initial readings of those measurements. The measurements they used were arterial oxygen saturation during the height of exercise; an exercise-capacity reading known as six-minute walking distance, or 6-MWD; levels of the biomarker NTproBNP, which evaluates the severity of heart decline; and an echocardiogram of right heart function.

Two factors were more highly correlated with death than the others, researchers found: increased levels of NTproBNP and decreased right heart function. In contrast, patients with a better prognosis were those whose 6-MWD test results changed by fewer than 50 meters or who had less than a 5 percent change in arterial oxygen saturation during the height of exercise.

Another finding was that death rates were higher among those whose PAH had deteriorated to Stage IV on the World Health Organization functional classification. With that scale, the higher the stage, the worse the symptoms.

“Mortality rates in adults with PAH-CHD remain significant,” the team wrote. “Current treatment decisions are based on the evaluation of baseline parameters [initial measurements] with an association with mortality, according to the PAH guidelines. We demonstrated the prognostic value of serial changes in standard clinical parameters in patients with PAH-CHD.

“Our results emphasize the importance of screening for serial changes in these parameters, since periodical assessment could guide treatment decisions” that delay the progression of the disease, the researchers concluded.