Echocardiographic Grading System Could Better Risk Stratify People with PAH

New research suggests that mapping out the relationships between right heart function values can help clinicians better risk-stratify patients with pulmonary arterial hypertension (PAH).

The report aims to create consistency out of a number of observations about associations between echocardiographic values by analyzing them in the context of real-world patient outcomes.

Corresponding author Bettia E. Celestin, PhD, of Stanford University, and colleagues, said a number of biomarkers for right heart failure (RHF) have been identified in the past three decades. They noted that RHF is the most important cause of mortality in PAH. Those biomarkers include triscuspid annular plane systolic excursion (TAPSE), right ventricular (RV) free wall longitudinal strain, right ventricular end systolic dimension, and right atrial (RA) size and function.

“With the multiplicity of right heart parameters, ensuring consistency in grading systems becomes even more important,” Celestin and colleagues said, writing in the journal Pulmonary Circulation.

The team advises that one way to ensure consistency is to leverage the relationships between different right heart parameters.

They noted, among other relationships, that a 2020 study found links between RV free wall longitudinal strain and right ventricular ejection fraction in patients with pulmonary hypertension.

“These physiological relationships can help ensure consistency between thresholds for risk stratification,” they said. “In addition, they can help guide consistency between grading systems in PAH.”

Celestin and colleagues set out to evaluate those relationships by comparing them to patient outcomes. They constructed a cohort of patients with Group 1 PAH who underwent right heart catheterization and echocardiography within 2 weeks of each other at Stanford Hospital. The patients were all adults, and their diagnoses came between 2002 and 2021.

The authors evaluated a number of echocardiographic variables, and then tracked patients to see which patients experienced death or lung transplant over the course of 5 years.

Of the 223 patients who met inclusion criteria, 78% were female, and the group had an average age of 48.1 years. The patients had a mean pulmonary arterial pressure of 51.6 (13.8) mmHg and pulmonary vascular resistance index of 22.5(6.3) WU/m2, the authors found.

As with previous studies, the authors found correlations between right heart parameters. Specifically, they found RV free wall longitudinal strain and RV fractional area change were closely linked, though they found TAPSE and RV free wall longitudinal strain had a weaker relationship.

At 5 years, 35% of patients had experienced either death or a lung transplant. The authors then used those outcomes to create an echocardiographic grading system for PAH, and then used those thresholds to assess the Registry to Evaluate Early and Long-Term PAH Disease Management echocardiographic risk score (REVEAL-ECHO), which was published last year.

In the latter analysis, they found REVEAL-ECHO scores were associated with survival in their validation cohort. The authors also found that REVEAL Lite scores correlated with patient outcomes. Those with a score of at least 8 had a 20% risk of death or transplantation at 1 year, and a 50% risk at 5 years.

The investigators said the mathematical relationships they identified between right heart parameters have implications for clinical practice. For example, they said if a patient is found to have highly discordant RV fractional area change and RV free wall longitudinal strain values, further investigation is warranted to make sure the readings are accurate.

“In addition, the strong association between many variables will likely simplify the number of features needed for phenomapping and profiling,” they wrote. “Finally, these mathematical relationships may further verify consistency in grading between metrics.”

The investigators said there are limitations to their study, including factors related to its single-center setting. For instance, they said their measures were performed in a laboratory dedicated to right heart measures, and thus may not be reflective of usual clinical practice.