Assessment of right ventricular function in advanced heart failure with nonischemic dilated cardiomyopathy: insights of right ventricular elastance.

Background: The right ventriculoarterial coupling (R-V/A), a measure of right ventricular systolic dysfunction (RVSD) adaptation/maladaptation to chronic overload, and consequent pulmonary hypertension, has been little investigated in nonischemic dilated cardiomyopathy (NIDCM). We examined the correlates of R-V/A and traditional echocardiographic indices of RVSD, over the spectrum of pulmonary hypertension and tertiles of mean pulmonary artery pressures (PAPm).
Methods: In 2016-2017, we studied 81 consecutive patients for heart transplant/advanced heart failure. Inclusion criteria were NIDCM, reduced ejection fraction (≤40%) and sinus rhythm. R-V/A was computed as the RV/pulmonary elastances ratio (R-Elv/P-Ea), derived from a combined right heart catheterization/transthoracic- echocardiographic assessment [right heart catheterization/transthoracic-echocardiographic (RHC/TTE)].
Results: A total of 68 patients (mean age 64 ± 7 years, 82% men) were eligible. After adjustments, R-Elv and P-Ea were higher in isolated postcapillary-pulmonary hypertension (Ipc-PH) than combined-pulmonary hypertension (Cpc-PH) (P = 0.004 and P = 0.002, respectively), whereas R-V/A progressively decreased over Ipc-PH and Cpc-PH (P = 0.006). According to PAPm increment, P-Ea congruently increased (P-Trend = 0.028), R-Elv progressively decreased (P-Trend<0.00)1, whereas R-V/A significantly worsened (P-Trend = 0.045). At the multivariable analysis, a reduced RV longitudinal function (TAPSE<17 mm) was positively associated with R-V/A impairment (<0.8) [odds ratio 1.41, 95% confidence interval (CI) (1.07--1.87), P = 0.015]. R-Elv and P-Ea showed good interobserver reliability [interclass correlation (ICC) 0.84, 95% CI (0.32--0.99), P = 0.012 and ICC 0.98, 95% CI (0.93--99), P < 0.001, respectively].
Conclusion: Among NIDCM HF patients, in a small cohort study, RHC/TTE-derived R-V/A assessment demonstrated good correlations with pulmonary hypertension types and RV functional status. These data suggest that R-V/A encloses comprehensive information of the whole cardiopulmonary efficiency, better clarifying the amount of RVSD, with good reliability.