Baba, Nima

Background: A key determinant of prognosis in pulmonary hypertension (PH) is the right ventricle’s (RV) ability to adapt to increased pulmonary vascular resistance. Consequently, markers of RV-pulmonary artery (PA) coupling may improve prognostic prediction in PH. The ratio of tricuspid annular plane systolic excursion (TAPSE) to systolic PA pressure (sPAP) has been proposed as a surrogate for RV-PA coupling and a reliable prognostic marker, however, the existing data on the prognostic value of the ratio between RV longitudinal strain (RVLS) and sPAP as a surrogate for RV-PA coupling is scarce. Hypothesis: To evaluate the prognostic role of RVLS/RVSP in PH patients and to compare this novel marker with established markers of RV-PA coupling. Methods: This is a single-center study that included adult patients with PH classified as group I or IV, all of whom had undergone a transthoracic echocardiogram (TTE) within one year prior to the initiation of PH-specific treatment. Certified sonographers procured RV strain measurements using a specific software (Epsilon Imaging, Ann Arbor, MI). Receiver operating characteristic (ROC) analysis was used to determine the best cutoff for predicting all-cause mortality at one-year for RVLS/RVSP and TAPSE/RVSP. The association of RVLS/RVSP and TAPSE/RVSP with mortality at one year was assessed using the Kaplan-Meier analysis and multivariate Cox regression analysis (adjusted for REVEAL LITE 2.0 risk score). Results: A total of 160 patients were included with a median age of 67.2 (56.8, 73.7) years and 47 (29.2%) were male . ROC analysis revealed optimal cutoffs of 0.265 (AUC = 0.83) for RVLS/RVSP and 0.185 (AUC = 0.77) for TAPSE/RVSP to predict all-cause mortality at one year. One-year cumulative incidence of all-cause mortality was lower among patients with RVLS/RVSP ≥ 0.265 (0 % vs 13.7 %, p = 0.001) and patients with TAPSE/RVSP ≥ 0.185 (1.8 % vs 16.7 %, p = 0.001) (Figure 1) . In the multivariate analysis, RVLS/RVSP < 0.265 was associated with higher risk of mortality at one year (HR: 2.38, 95 % CI: 1.05 to 5.38, p = 0.036) while TAPSE/RVSP < 0.185 was not (HR: 2.01, 95 % CI: 0.93 to 4.31, p = 0.072). Conclusions: RVLS/ RVSP may be a valuable prognostic marker in PH patients and could outperform conventional TTE parameters as a surrogate for detecting RV-PA coupling.