Right ventricular function correlates of right atrial strain in pulmonary hypertension: a combined cardiac magnetic resonance and conductance catheter study

Abstract

The functional relevance of right atrial (RA) function in pulmonary hypertension (PH) remains incompletely understood. The purpose of this study was to explore the correlation of cardiac magnetic resonance (CMR) feature tracking-derived RA phasic function with invasively measured pressure-volume (P-V) loop-derived right ventricular (RV) end-diastolic elastance ( Eed) and RV-arterial coupling [ratio of end-systolic elastance to arterial elastance ( Ees/ Ea)]. In 54 patients with severe PH, CMR was performed within 24 h of diagnostic right heart catheterization and P-V measurements. RA phasic function was assessed by CMR imaging of RA reservoir, passive, and active strain. The association of RA phasic function with indexes of RV function was evaluated by Spearman’s rank correlation and linear regression analyses. Median [interquartile range] RA reservoir strain, passive strain, and active strain were 19.5% [11.0–24.5], 7.0% [4.0–12.0], and 13.0% [7.0–18.5], respectively. Ees/ Ea was 0.73 [0.48–1.08], and Eed was 0.14 mmHg/mL [0.05–0.22]. RV diastolic impairment [RV end-diastolic pressure (EDP) and Eed] was correlated with RA phasic function, but Ea and Ees were not. In addition, RA phasic function was correlated with inferior vena cava diameter. In multivariate linear regression analysis, adjusting for key P-V loop indexes, Eed and EDP remained significantly associated with RA phasic function. We conclude that RA phasic function is altered in relation to impaired diastolic function of the chronically overloaded right ventricle and contributes to backward venous flow and systemic congestion. These results call for more attention to RA function in the management of patients with PH. NEW & NOTEWORTHY There is growing awareness of the importance of the right atrial (RA)-right ventricular (RV) axis in pulmonary hypertension (PH). Our results uncover alterations in RA phasic function that are related to depressed RV lusitropic function and contribute to backward venous return and systemic congestion in chronic RV overload. Assessment of RA function should be part of the management and follow-up of patients with PH.

Cardiac Magnetic Resonance in Pulmonary Hypertension—an Update

“…Impaired right atrial (RA) strain and phasic function are a marker of disease severity. Reduced RA strain is associated with decompensated RV function and stiffness [ 48 , 49 ]. The advancement of fully automated myocardial strain analysis is likely to push its role in future research in the diagnosis and prognosis of PH [ 50 ].…”

MRI feature tracking strain in pulmonary hypertension: utility of combined left atrial volumetric and deformation assessment in distinguishing post- from pre-capillary physiology

“…In a canine PH model by PA banding, early compensation was characterised by preserved systolic but impaired RV diastolic function, and increased RA distensibility (increased reservoir strain) [26]. The latter would be counterpoise for RV diastolic dysfunction and avert clinical heart failure but with worsening PH severity/chronicity, RV-PA then RV-RA uncoupling would ensue with diminution of RA reservoir function causing symptoms [27,28]. Strain cut-points have been proposed to accompany this trajectory of maladaptation [27,29,30] with RV-PA decoupling occurring at RV GLS >-15.29% and later stage RV-RA decoupling corresponding to a RA reservoir strain < 16%.…”

“…The latter would be counterpoise for RV diastolic dysfunction and avert clinical heart failure but with worsening PH severity/chronicity, RV-PA then RV-RA uncoupling would ensue with diminution of RA reservoir function causing symptoms [27,28]. Strain cut-points have been proposed to accompany this trajectory of maladaptation [27,29,30] with RV-PA decoupling occurring at RV GLS >-15.29% and later stage RV-RA decoupling corresponding to a RA reservoir strain < 16%. In this cross-sectional work, precapillary PH patients had a mean RV GLS of -10.1% and peak RA strain of 18.8% suggesting uncoupled RV-PA but preserved RV-RA relationships and underlie our nding of lack of mortality prediction by peak RA strain.…”

Quantification of Myocardial Deformation Applying CMR-Feature-Tracking—All About the Left Ventricle?

“…An involvement of the right heart is often associated with more profound pulmonary vascular dysfunction and pulmonary hypertension as an expression of later stages of HF, therefore, contributes significantly to poor prognosis [112]. Indeed, CMR-FT RV and RA analyses were shown to correlate with invasively measured pressure-volume loops encouraging imaging specialists to attribute greater importance to the right heart involvement in HF patients for a more comprehensive understanding of right heart function and stiffness properties as well as a maladaptation to post-capillary pulmonary hypertension in HF [113]. Detecting functional impairments at early stages of HFpEF, recently, a study identified especially LA failure during exercise stress as a key feature in these patients [114].…”