Prognostic dissociation between right atrial and right ventricular metrics in treated pulmonary hypertension
C Kocx, T Barlow, A Pearlman, S Lal, D S CelermajerAbstract
Background
Risk stratification in pulmonary hypertension (PH) relies heavily on right heart echocardiography. However, RA and RV parameters are typically analysed together, assuming they provide concordant prognostic information. Recent pressure-volume loop and cardiomyocyte data suggest that RA adaptation in PH is a compensatory response to RV diastolic stiffness rather than independent atrial failure (Wessels, JACC 2023). We investigated whether RA and RV metrics retain equivalent prognostic value in patients established on PH therapy.
Methods
Retrospective analysis of right heart echocardiography in 47 consecutive PH patients (94% on pulmonary vasodilator therapy) enrolled in care at a state wide referral centre was undertaken. RA metrics included geometry (area, area index, volume index), deformation (reservoir, conduit, and contractile strain), and function (emptying fraction). RV metrics included geometry (basal diameter, basal index, area index), conventional function (FAC, S', TAPSE), and deformation (RVFWSL, RV4CSL). Cox regression assessed association with all-cause mortality over median 2.9 years follow-up.
Results
Among 16 deaths (34%), a striking dissociation emerged between atrial and ventricular prognostic utility (See table). RA metrics uniformly failed regardless of assessment modality; geometry (0/3), deformation (0/3), and function (0/1). RV metrics showed selective prognostic value: geometry and conventional function (FAC, S') failed, while deformation-based metrics (RVFWSL, RV4CSL, TAPSE) predicted mortality. RA emptying fraction showed a paradoxical trend (HR >1, p=0.055), higher EF associated with worse survival. This findings concurs, that RA stroke work increases as compensation for RV diastolic stiffness. Thus, hypercontractility marks disease severity rather than physiological reserve.
Conclusion
In treated PH, prognostic information is compartmentalised to RV deformation metrics. The universal failure of RA parameters (geometry, phasic strain, and function) is consistent with cardiomyocyte data showing no intrinsic RA sarcomeric dysfunction in this population. The paradoxical RA EF signal further suggests that RA hypercontractility reflects compensatory stroke work against a stiff ventricle. Risk models in prevalent PH cohorts should prioritise RV strain over both atrial parameters and conventional RV indices.Table of ParametersFor image description, please refer to the figure legend and surrounding text.Forest Plot of ParametersFor image description, please refer to the figure legend and surrounding text.