Changes in ventricular function and myocardial deformation in patients treated with trastuzumab

Introduction

Trastuzumab is a cornerstone therapy for HER2-positive breast cancer, but it is associated with an increased risk of cardiotoxicity, mainly left ventricular (LV) dysfunction. Left ventricular ejection fraction (LVEF) is traditionally used for cardiac monitoring, although it may fail to detect early or subclinical myocardial impairment. Global longitudinal strain (GLS) has emerged as a more sensitive marker of early ventricular dysfunction. Data on right ventricular (RV) involvement and the role of cardiovascular risk factors and biomarkers remain limited.

Objectives

To evaluate the impact of trastuzumab treatment on left ventricular function assessed by LVEF and LV global longitudinal strain, to analyze right ventricular involvement, and to explore the association with cardiovascular risk factors and cardiac biomarkers.

Materials and Methods

We conducted a retrospective observational study including oncology patients treated with trastuzumab and followed in a cardio-oncology clinic. All patients had a baseline echocardiogram before treatment and at least one follow-up study. Clinical characteristics, cardiovascular risk factors, cardiac biomarkers (BNP/proBNP and troponin T), LVEF, LV-GLS, and RV longitudinal strain (when available) were analyzed.

Results

A total of 73 patients were included (97.3% women, mean age 60.8 ± 12.9 years). Baseline LVEF was 61.8 ± 5.3%. After treatment, LVEF decreased significantly to 57.6 ± 6.5%, with a mean reduction of 4.17 ± 6.65 percentage points (p < 0.001). LVEF decline was observed in 71.2% of patients and was ≥10% in 34.0%.

LV-GLS worsened significantly from −20.1 ± 3.1% to −17.4 ± 3.0% (mean reduction −2.68 ± 3.07%, p < 0.001), with GLS reduction in 57.8% of patients. No significant association was found between LVEF decline and GLS reduction (p = 0.756).

RV strain was available in 43 patients and remained within preserved ranges, with no significant correlation with post-treatment LVEF. Cardiac biomarkers shifted toward higher categories after treatment. Type 2 diabetes mellitus was associated with a lower incidence of LV-GLS reduction.

Conclusion

Trastuzumab treatment is associated with significant deterioration of left ventricular function assessed by both LVEF and GLS. GLS confirms its role as a sensitive marker of subclinical cardiotoxicity, complementary to LVEF. Right ventricular involvement appears limited in this cohort. Comprehensive cardiac monitoring remains essential in patients receiving trastuzumab.