Global longitudinal strain: an early marker for cardiotoxicity in patients treated for breast cancer.

Background: Patients treated with anthracyclines and trastuzumab are at increased risk of developing heart failure. Early diagnosis and treatment may prevent irreversible left ventricular (LV) dysfunction. This study investigates whether subclinical deterioration of global longitudinal strain (GLS) is a more reliable early predictor for LV dysfunction than three-dimensional (3D) LV ejection fraction (LVEF).

Methods: Adult patients receiving anthracyclines and trastuzumab for breast cancer who had serial echocardiographic follow-up were included in this retrospective study. The primary endpoint was the necessity to temporarily pause chemo- or immunotherapy due to declining LVEF (decline in 3D LVEF of > 10 percentage points to < 53%). Linear mixed-effects models were used to assess the longitudinal evolution of 3D LVEF and GLS over time.

Results: Fifty-one women were included, mean age 54 (50.5-57.6) years, with a total of 216 follow-up echocardiograms (mean follow-up 1.1 ± 0.45 years). GLS and 3D LVEF were significantly correlated (Spearman's rho: -0.36, p < 0.001). A decrease in GLS significantly predicted a lower LVEF on the subsequent echocardiogram [ß -0.6, 95% confidence interval (CI) (-1.0 to -0.2), p < 0.006]. Conversely, prior LVEF did not significantly predict GLS on the subsequent echocardiogram [ß -0.04, 95% CI -0.1 to -0.01, p = 0.12]. Nine patients reached the primary endpoint. On average, patients who reached the primary endpoint had a relative decrease of 15% GLS at day 205 and an absolute 10% decrease of LVEF to LVEF < 53% at day 235.

Discussion: GLS is able to identify subclinical LV dysfunction earlier than 3D LVEF measurement in women undergoing treatment for breast cancer with anthracyclines followed by trastuzumab.