[Two-dimensional speckle-tracking echocardiography in radiotherapy-related right heart dysfunction and analysis of associated risk factors].

Objective: To evaluate the impact of radiotherapy on right ventricular function using two-dimensional speckle-tracking echocardiography (2D-STE) in patients with thoracic tumors, and to identify factors associated with radiotherapy-induced right ventricular dysfunction. Methods: Patients who received thoracic radiotherapy at the Fourth Hospital of Hebei Medical University between May 2021 and May 2022 were enrolled in this study. 2D-STE examinations were performed before, during (upon completion of half of the prescribed radiotherapy dose), and after radiotherapy (1 to 2days after the end of radiotherapy). The 2D-STE evaluation parameters included left ventricular global longitudinal strain (LVGLS) and right ventricular free wall longitudinal strain (RVFWLS). The difference between post-treatment RVFWLS and the baseline value (ΔRVFWLS) and the percentage change in RVFWLS were calculated. Right ventricular dysfunction was defined as a right ventricular fractional area change (FAC)<35% or tricuspid annular systolic peak velocity at the right ventricular free wall<10 cm/s. Multiple linear regression analysis was performed to investigate the associations of age, cardiac volume, radiotherapy parameters, and other factors with ΔRVFWLS and the percentage change in RVFWLS. Receiver operating characteristic (ROC) curve analysis was used to assess the predictive performance of the relevant factors for right ventricular dysfunction, and the Kaplan-Meier method was adopted for survival analysis. Results: A total of 40 patients were enrolled in this study, including 22 males, with a median age of 61.0 years. Compared with baseline, right ventricular FAC ((45.48±4.67)% vs. (51.75±6.55)%, P<0.05), LVGLS ((-16.83±2.99)% vs. (-18.85±3.00)%, P<0.05), and RVFWLS ((-25.69±2.29)% vs. (-28.86±1.26)%, P<0.05) decreased during treatment. These parameters remained lower than the baseline levels after treatment (all P<0.05). Multiple linear regression analysis demonstrated that mean heart dose (MHD) and patient age were linearly correlated with ΔRVFWLS and the percentage change in RVFWLS (all P<0.05). ROC curve analysis revealed that the area under the curve (AUC) of MHD for predicting right ventricular dysfunction was 0.984, with a cut-off value of 2 020 cGy; the AUC for patient age was 0.766, with a cut-off value of 56.5 years. The median follow-up duration was 82days, and 11 (28%) patients developed right ventricular dysfunction. The Kaplan-Meier survival curve indicated that the cumulative incidence of endpoint events was higher in patients aged ≥56.5 years than in those aged <56.5 years (Plog-rank=0.020). The cumulative incidence of endpoint events was higher in patients with an MHD ≥2 020 cGy than in those with an MHD <2 020 cGy (Plog-rank<0.001). Conclusions: 2D-STE allows early detection of right ventricular dysfunction. Patient age and MHD are factors associated with radiotherapy-induced right ventricular dysfunction.