Evaluation of left ventricular systolic function and synchrony in patiests with early left breast cancer after breast conserving radiotherapy by layer-specific strain technique

Objective To evaluate the left ventricular systolic function and synchronization of patients with early left breast cancer after breast conserving radiotherapy by layer-specific strain technique. Methods Thirty-six patients with early left breast cancer who underwent breast surgery and radiotheraphy in Affiliated Tumor Hospital of Zhengzhou University from January 2018 to January 2019 were selected for this study. The layered strain technique was respectively applied to collect two-dimensional dynamic ultrasonic cardiograms one week before radiotherapy, one week after radiotherapy, and six months after radiotherapy. The EchoPAC 201 software was applied to analyze and obtain the global longitudinal peak strain(GLPS) and peak stain dispersion(PSD) of the epicardial layer(epi), the middle layer(mid) and endocardial layer(endo) of 17 left ventricular segments. The differences of every parameter before and after radiotherapy were compared, and the correlation of PSD and other parameters was analyzed. Results Compared with one week before radiotherapy, the absolute values of LPSepi, LPSmid, LPSendo, and GLPS all reduced significantly one week and six months after radiotherapy, and PSD increased significantly (P<0.05). Compared with one week after radiotherapy, the LPS absolute value of every layer and GLPS obviously reduced after six months, PSD obviously increased, the difference had statistical significance (P<0.05). PSD and GLPS displayed negative correlation one week after radiotherapy (r=-0.420, P<0.05), PSD and GLPS displayed negative correlation six months after radiotherapy (r=-0.641, P<0.05). Conclusions Layered strain technique can noninvasively and quantitatively evaluate the early changes of global and layered longitudinal peak strain and systolic synchrony of left ventricle in left breast cancer breast-conserving radiotherapy patients, and provides a new noninvasive test method for evaluating radioactive myocardial injury, and it has a certain guiding value to early clinical intervention and treatment of cardiovascular complications. Key words: Breast cancer, early; Radiotherapy; Layer-specific strain; Peak strain dispersion