Myocardial damage pattern in women with breast cancer who underwent chemotherapy: strain polar maps analysis

Purpose To confirm GLS diagnostic sensitivity as parameter for the evaluation of LV systolic function in women with breast cancer who underwent chemotherapy including anthracyclines and to identify a pattern of decreased 2D speckle tracking regional longitudinal strain through the analysis of polar maps obtained with AFI technology. Methods: We enrolled 40 female patients (age with 55.5±11 years) with breast cancer before the beginning of chemotherapy. The study protocol included clinical examination, ECG with QTc calculation, lab test (BNP and troponin I) and echocardiography with TDI and speckle tracking analysis (STI), that were performed before the beginning of the chemotherapy (basal) and after 3, 6 and 12 months. Echocardiography evaluation included the following parameters: LV end­diastolic and end­systolic volumes, LV ejection fraction (EF), average TDI S’ at the mitral annulus, Global Longitudinal Strain (GLS), regional longitudinal strain, E/A ratio, E/E’ ratio and sPAP. For each patient we analyzed the bull’s eye maps before the beginning of the therapy (basal value) and when GLS showed the lowest values during the FU (FU value), to identify the pattern of regional longitudinal strain alterations. We compared basal and FU strain values for each of the 17 LV segments and the difference between them (delta) was calculated according to the formula [(FU LS –basal LS, (%)]. ResultsDuring the FU, systolic blood pressure, systolic pulse pressure and BNP values increased from the basal assessment to the 3 and 6 months FU. Similarly, a progressive worsening of GLS values has been observed (basal ­20.4±2.6%, 3 months FU ­18.2 ±2.5%, 6 months FU ­17.7± 2.9, 12 months FU ­17.6± 3, p value <0.001). Through the analysis of polar maps, we observed that regional strain values worsened significantly in all the LV segments but the most evident impairment was reported in the apical cap (­22.8±3.9 vs ­17.1±3.8; p <0.001, ?=­5,78%) and in the apical segment of the anterior interventricular septum (­23.4±4.5 vs ­17±6.3; p<0.001, ?=­6,2%), as reported in Figure 1. Conclusion: GLS is able to identify LV systolic dysfunction that EF is not able to detect. However, since that it describes the global function of LV, GLS could result as normal (18­20%) when strain impairment of some LV segments is counterbalanced by the compensatory strain increase of other segments, determining an misdiagnosis of myocardial damage. Regional strain and particularly the ?­strain, seem to suggest that anthracyclines induce a damage more evident in the apical cap and in the apical segment of the interventricular septum and this pattern could be typical in these patients. Thus, polar maps analysis could be provide additional information about cardiac damage in this population.