Noninvasive measure has prognostic value in PAH

By Eleanor McDermid, Senior medwireNews Reporter

Estimated right atrial pressure (eRAP), measured using echocardiography, may be a useful prognostic indicator in patients with pulmonary arterial hypertension (PAH), a study suggests.

In a retrospective analysis of 121 patients with PAH, an elevated eRAP was significantly associated with reduced transplant-free survival, report Brian Shapiro (Mayo Clinic Florida, Jacksonville, USA) and study co-authors in Chest.

High eRAP was defined as greater than 15 mmHg, according to the American Society of Echocardiography (ASE) 2005 guidelines, based on a maximum inferior vena cava (IVC) diameter greater than 1.7 cm and collapsibility index below 25%.

Across 3 years of follow-up, transplant-free survival ranged from 82% for patients with low eRAP to 13% for those with high eRAP.

None of the other echocardiography parameters assessed predicted mortality after accounting for confounders, including high eRAP as defined in the 2010 ASE guidelines (IVC maximum >2.1 cm and collapsibility index <50%).

The likelihood of death or transplant was increased 7.94-fold for patients with elevated eRAP according to the 2005 ASE definition (>15 vs ≤5 mmHg) and 2.61-fold according to the 2010 definition (high vs normal). But in multivariate analysis, only the 2005 definition was associated with death or transplant, at a 2.28-fold increased risk.

The superior predictive value of the 2005 definition was despite the 2010 definition being slightly more likely to produce an eRAP value within 5 mmHg of the right heart catheterisation value, at 68.6% versus 63.6% for the 2005 definition. The 2010 definition less frequently overestimated eRAP, at 9.1% versus 24.0%, but more often underestimated it.

The team also assessed the prognostic value of right atrial area (RAA) “since eRAP may be technically prohibitive in some patients”.

Patients with an enlarged RAA (>18 cm²) had a transplant-free survival rate of 50%, compared with 76% among those with a normal RAA, equating to a 2.56-fold increased risk among those with an enlarged RAA. However, this did not retain significance on multivariate analysis.

The researchers conclude that eRAP is an “inexpensive and easily obtained predictive measure” in PAH patients and should be “an essential component of the right heart evaluation.”

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