Cardiac Magnetic Resonance Imaging-Based Right Ventricular Strain Analysis for Assessment of Coupling and Diastolic Function in Pulmonary Hypertension

Objectives: This study sought to compare cardiac magnetic resonance (CMR) imaging-derived right ventricular (RV) strain and invasively measured pressure-volume loop-derived RV contractility, stiffness, and afterload and RV-arterial coupling in pulmonary hypertension (PH).

Background: In chronic RV pressure overload, RV-arterial uncoupling is considered the driving cause of RV maladaptation and eventual RV failure. The pathophysiological and clinical value of CMR-derived RV strain relative to that of invasive pressure-volume loop-derived measurements in PH remains incompletely understood.

Methods: In 38 patients with PH, global RV CMR strain was measured within 24 h of diagnostic right heart catheterization and conductance (pressure-volume) catheterization. Associations were evaluated by correlation, multivariate logistic binary regression, and receiver operating characteristic analyses.

Results: Long-axis RV longitudinal and radial strain and short-axis RV radial and circumferential strain were -18.0 ± 7.0%, 28.9% [interquartile range (IQR): 17.4% to 46.6%]; 15.6 ± 6.2%; and -9.8 ± 3.5%, respectively. RV-arterial coupling (end-systolic [Eds]/arterial elastance [Ea]) was 0.76 (IQR: 0.47 to 1.07). Peak RV strain correlated with Ees/Ea, afterload (Ea), RV diastolic dysfunction (Tau), and stiffness (end-diastolic elastance [Eed]) but not with contractility (Ees). In multivariate analysis, long-axis RV radial strain was associated with RV-arterial uncoupling (Ees/Ea: <0.805; odds ratio [OR]: 5.50; 95% confidence interval [CI]: 1.50 to 20.18), whereas long-axis RV longitudinal strain was associated with increased RV diastolic stiffness (Eed: ≥0.124 mm Hg/ml; OR: 1.23; 95% CI: 1.10 to 1.51). The long-axis RV longitudinal strain-to-RV end-diastolic volume/body surface area ratio strongly predicted RV diastolic stiffness (area under receiver operating characteristic curve: 0.908).

Conclusions: In chronic RV overload, CMR-determined RV strain is associated with RV-arterial uncoupling and RV end-diastolic stiffness and represents a promising noninvasive alternative to current invasive methods for assessment of RV-arterial coupling and end-diastolic stiffness in patients with PH. (Right Ventricular Haemodynamic Evaluation and Response to Treatment [Rightheart I]; NCT03403868).