Right ventricular (RV) strain assessed via cardiac magnetic resonance (CMR) feature tracking is significantly associated with RV diastolic function, stiffness, and afterload, according to a study published in JACC Cardiovascular Imaging.
The study researchers analyzed consecutive patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension (PH) who underwent CMR imaging to measure pulmonary arterial stiffness, capacitance, and distensibility (N=38). Imaging was performed with a 1.5 Tesla scanner system and included axial, coronal, and sagittal thoracic survey images.
RV short axis radial strain was correlated with RV dilatation; RV longitudinal, radial, and circumferential strain showed significant decreases in patients with severely dilatated vs non-dilatated right ventricles. Short axis circumferential strain and long axis longitudinal strain were associated with pulmonary arterial stiffness (rho, 0.398; P =.024). Long axis longitudinal strain showed a significant correlation with distensibility (rho, -0.406, P =.019).
Multivariate logistic regression analysis showed that long axis RV radial strain remained independently associated with Ees/Ea dichotomized at 0.805 mm Hg/mL (multivariate odds ratio [OR], 5.50; 95% CI, 1.50-20.18; P =.010) and with Ea dichotomized at 0.66 mm Hg/mL (multivariate OR, 0.96; 95% CI, 0.92-0.995; P =.026).
This study was potentially limited by the single-beat method to estimate Eed, Ees, and Ea; it is not yet known whether the multiple-beat approach would produce the same results. Reference values for Ees, Ea, and Eed, as well as the Ees/Ea cut-off at which RV maladaptation begins have not yet been precisely determined and were estimated for this study. The sample size also prevented meaningful analysis of the effects of race and sex on the results.
Researchers found that, “Our data show that CMR RV strain is a promising indicator of RV-arterial uncoupling and diastolic RV stiffness, broadening the already substantial range of potential applications for CMR in the assessment of RV function during follow-up of patients with PH. Furthermore, our findings help to close the knowledge gap regarding the physiology of RV strain in chronic pressure overload.”
Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Tello K, Dalmer A, Vanderpool R, et al. Cardiac magnetic resonance imaging-based right ventricular strain analysis for assessment of coupling and diastolic function in pulmonary hypertension [published March 13, 2019]. JACC Cardiovasc Imaging. doi:10.1016/j.jcmg.2018.12.032