Routine use of Global Longitudinal Strain Among Active Breast Cancer Patients: A Cardio-Oncology Registry

Background: Increased survival among breast cancer patients exposed a wide range of side effects, with cardiotoxicity being the most significant one. Cancer therapeutic related cardiac dysfunction (CTRCD) is defined as a left ventricular ejection fraction (LVEF) reduction of >10 % points, to a value below 50%. Unfortunately, a detectable drop in LVEF occurs only after the loss of a substantial amount of myocardial tissue, and in up to 58% of these patients the ventricular function will not recover. Therefore, according to the American and European Society of Echocardiography, global longitudinal strain (GLS) is the optimal parameter for early detection of subclinical LV dysfunction, with a relative reduction of ≥15% considered to be clinically significant. However, due to the lack of studies routine use of GLS has not been fully adopted.

Objectives: Evaluating the frequency of significant GLS reduction and whether it predicts CTRCD development among active breast cancer patients.

Methods: Data was collected as part of the International Cardio-Oncology Registry (ICOR), enrolling all patients evaluating in the cardio-oncology clinic in our institution. All patients performed at least two GLS examinations by the same vendor, technician and interpreting cardiologist.

Results: Among 103 consecutive patients, 5 (5%) developed CTRCD for which lower baseline GLS (18± 3 vs. 21±2, p=0.016) was a significant predictor. Among 79 patients, 9 (11%) developed significant GLS reduction, of which 44% had no concomitant EF reduction. Median time for GLS reduction was 93 days. There were no significant differences in the baseline cardiac risk factors and no predictors for GLS reductions were identified, including blood test or echocardiography parameters. (Table 1).

Conclusions: Our study demonstrates that GLS reduction is frequent among breast cancer patients, precedes LVEF reduction and cannot be anticipated by other echocardiographic parameters. Using GLS routinely may lead to an early diagnosis and prevention of cardiotoxicity.

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