3-Year Follow-Up of Radiation-Associated Changes in Diastolic Function by Speckle Tracking Echocardiography.

BACKGROUND

Radiation therapy (RT) results in myocardial changes consisting of diffuse fibrosis, which may result in changes in diastolic function.

OBJECTIVES

The aim of this study was to explore RT-associated changes in left ventricular (LV) diastolic function.

METHODS

Sixty chemotherapy-naive patients with left-sided, early-stage breast cancer were studied with speckle tracking echocardiography at 3 time points: prior to, immediately after, and 3 years after RT. Global and regional early diastolic strain rate (SRe) were quantified, as were parameters of systolic function.

RESULTS

Regional changes in SRe, particularly the apical and anteroseptal segments, were observed over time and were more evident than global changes. The apical SRe declined from a median of 1.24 (interquartile range: 1.01 to 1.39) s-1 at baseline to 1.02 (interquartile range: 0.79 to 1.15) s-1 at 3 years of follow-up (p < 0.001). This decline was associated with the left ventricular maximal radiation dose (β = 0.36, p = 0.007). The global SRe was <1.00 s-1 (SRedep) in 11 (18.3%) patients at baseline, 21 (35%) patients (p = 0.013) post-RT, and 17 (28.3%) patients (p = 0.051) at 3 years. SRedep post-RT was independently associated with baseline cardiac abnormalities (odds ratio: 0.26; 95% confidence interval: 0.08 to 0.84; p = 0.025); SRedep at 3 years of follow-up was associated with the baseline Charlson comorbidity index (odds ratio: 2.36; 95% confidence interval: 1.17 to 4.77; p = 0.017). Diastolic function abnormalities were evident even in patients with preserved global longitudinal strain at 3 years.

CONCLUSIONS

RT resulted in changes in the SRe in the apical and anteroseptal segments over 3 years of follow-up. Changes in SRe apical segments were present even in patients with preserved systolic function and were independently associated with RT dose and cardiovascular comorbidities.