Abstract 16399: Exercise Stress Testing With Strain Echocardiography is Superior to Resting Echocardiography in Identifying Doxorubicin-Induced Preclinical LV Dysfunction in Breast Cancer Patients
Introduction: In current clinical practice, the cardiovascular toxicity of chemotherapy is determined by resting LVEF which has limited ability to detect early-stage myocardial dysfunction. While recent advances in echo using strain imaging provide incremental value over LVEF, the prognostic value of VO2peak during cardiopulmonary exercise testing (CPET) suggests that exercise LV function may be an even more sensitive predictor of cardiac damage.
Hypothesis: We assessed the hypothesis that CPET in conjunction with echocardiographic strain imaging would improve the early identification of doxorubicin-induced myocardial dysfunction.
Methods: Thirty-eight asymptomatic breast cancer patients (post-doxorubicin, mean 35 ± 20 months) were studied with 11 age- and sex-matched healthy controls. All subjects completed a standard resting transthoracic echo (Vivid-7, GE Medical Systems) followed by symptom-limited treadmill CPET (to assess VO2peak) with immediate post-peak echo. Echo measurements included conventional indices of LV systolic and diastolic function and longitudinal and radial strain by speckle-tracking.
Results: There were no significant differences between patients and controls at rest and their rate-pressure products at peak exercise were similar. A trend towards lower VO2peak in patients was associated with a significant inability to augment LVEF and global longitudinal strain in response to exercise, as compared to healthy controls (table).
Conclusions: In comparison with age-matched healthy controls, breast cancer patients had impaired contractile reserve following maximal stress testing, despite lack of change in any resting parameter. In conclusion, exercise stress testing combined with echocardiographic speckle-based strain imaging may allow for earlier identification of doxorubicin-induced myocardial dysfunction not detectable under resting conditions.
- © 2011 by American Heart Association, Inc.