Right Ventricular Function Determines Survival in PAH Patients, Study Reports

Right ventricular function of the heart is the primary determining factor of survival in patients with pulmonary arterial hypertension (PAH) receiving specific treatments, a study suggests.

The study, “Predictors of poor outcome in patients with pulmonary arterial hypertension: A single center study,” was published in the journal PLOS ONE.

Despite the development of PAH-specific medical treatments, the disease’s prognosis remains challenging. In this observational study, researchers looked at the prognostic factors of poor outcome in a group of PAH patients from a single center in Poland. All 47 patients, which included 30 women, with a mean age of 39 years, were receiving PAH-specific medications.

The study also assessed if microvolt-level T-wave alternans (MTWA) testing — a noninvasive method to identify patients at greater risk of cardiac arrest and sudden cardiac death from ventricular arrhythmia — provides new valuable data for risk assessment in PAH.

All patients in the study underwent clinical assessments, laboratory measurements, electrocardiograms, echocardiographies, the six-minute walk test for exercise capacity, a cardiopulmonary exercise evaluation, and the 24-hour Holter monitoring to study heart activity at routine visits. The mean follow-up period was 2.6 years.

Eight patients died during follow-up. These patients had a concentration of brain natriuretic peptide (BNP) — a hormone released by cells in the heart muscle, and a marker of heart failure — of 330 pg/mL or higher. Their bilirubin levels — a substance generated from the breakdown of red blood cells and whose levels may indicate impaired liver function — were equal or higher than 1.2 mg/dL; and right atrial area, which reflects the function of the heart’s right ventricle, of 21 cm2 or greater.

They also had a right ventricular dimension higher than 47 mm — as determined by echocardiography — and right-to-left ventricular diastolic diameter ratio, which identifies patients at risk of heart failure, of 1.5 mm or higher.

Subsequent analysis revealed that higher BNP and bilirubin levels, higher right atrial area, and lower tricuspid annular plane systolic excursion (TAPSE, a measure of right ventricular function) were all independent predictors of mortality in PAH patients.

“Worse RV [right ventricular] function, as evidenced by lower TAPSE, higher BNP level, and enlarged right atrium, was associated with an increased mortality risk,” the researchers wrote.

However, the authors cautioned that the significance of individual parameters for PAH prognosis will be different depending on whether the patient just started a specialized treatment or is already under a combined therapeutic regimen.

Of note, no patient with a negative result on the MTWA test died during follow-up, which may indicate that negative MTWA results reflect better outcomes, the team hypothesized. Nonetheless, this finding requires confirmation in a larger PAH population.