Does the Presence of Pre-chemotherapy Left Ventricle Dysfunction Effect the Post-Chemotherapy Outcomes?

Background:
Although anthracyclines are effective in the treatment of pediatric cancers, their utility is limited by progressive cardiotoxicity, which can occur years after the completion of chemotherapy. Recent studies have reported abnormalities in left ventricular (LV) global endocardial longitudinal strain (GLS) in patients with cancer even prior to exposure to chemotherapy. The aim of our study was to assess the effect of abnormalities in pre-chemotherapy GLS on the GLS after completion of chemotherapy.

Methods:
This is a single centered retrospective analysis of echocardiograms and clinical chart of pediatric cancer patients before and after exposure to chemotherapy. Those with echocardiograms before and after chemotherapy were included for analysis. Patients who had undergone bone marrow transplantation and were still undergoing chemotherapy were excluded. Left ventricular peak LS was analyzed from apical 4, 3, and 2 chamber views using TomTech Imaging systems, a vendor independent software, as well the global LS. Abnormal LS was defined as less than -18.75, which is 2 standard deviations below the mean strain in a normal pediatric population. Statistical analysis was performed using SPSS version 22, and included student t-test and chi square test for comparison of the pre-chemotherapy and post-chemotherapy echocardiograms.

Results:
Our cohort (n=33) was 51% male; mean (SD) ages at time of pre- and post-chemotherapy echocardiograms were 9.1 (5.5) years and 12.6 (5.5) respectively. Peak LS and GLS significantly decreased following chemotherapy, compared to pre-chemotherapy baseline. Of the 13 patients with abnormal pre-chemotherapy LS, 9 (69%) continued to have abnormal LS after chemotherapy while 4 (31%) had normalization of strain. However, 9 (45%) patients with initial normal pre-chemotherapy LS strain developed abnormal strain after chemotherapy. One patient with normal GLS prior to chemotherapy developed LV systolic dysfunction requiring medical management.

Conclusion:
In patients undergoing chemotherapy for pediatric cancers, there was an overall decrease in peak and global LS, suggestive of changes in left ventricular modeling. More than two-thirds of patients with abnormal pre-chemotherapy GLS are at risk for developing abnormal LS post chemotherapy and should be monitored closely. A larger study is warranted to further confirm these findings.