Exercise as a diagnostic and therapeutic tool for the prevention of cardiovascular dysfunction in breast cancer patients

• Published in: European journal of preventive cardiology Vol. 26; no. 3; pp. 305 - 315
• Main Authors: Howden, Erin J, Bigaran, Ashley, Beaudry, Rhys, Fraser, Steve, Selig, Steve, Foulkes, Steve, Antill, Yoland, Nightingale, Sophie, Loi, Sherene, Haykowsky, Mark J, La Gerche, André
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01-02-2019
• Subjects: survivorship; heart failure; cardiotoxicity; Exercise; cardiorespiratory fitness
• ISSN: 2047-4873; 2047-4881
• DOI: 10.1177/2047487318811181

Background
Anthracycline chemotherapy may be associated with decreased cardiac function and functional capacity measured as the peak oxygen uptake during exercise (
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peak). We sought to determine (a) whether a structured exercise training program would attenuate reductions in
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peak and (b) whether exercise cardiac imaging is a more sensitive marker of cardiac injury than the current standard of care resting left ventricular ejection fraction (LVEF).
Methods
Twenty-eight patients with early stage breast cancer undergoing anthracycline chemotherapy were able to choose between exercise training (mean ± SD age 47 ± 9 years, n = 14) or usual care (mean ± SD age 53 ± 9 years, n = 14). Measurements performed before and after anthracycline chemotherapy included cardiopulmonary exercise testing to determine
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peak and functional disability (
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peak < 18 ml/min/kg), resting echocardiography (LVEF and global longitudinal strain), cardiac biomarkers (troponin and B-type natriuretic peptide) and exercise cardiac magnetic resonance imaging to determine stroke volume and peak cardiac output. The exercise training group completed 2 × 60 minute supervised exercise sessions per week.
Results
Decreases in
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peak during chemotherapy were attenuated with exercise training (15 vs. 4% reduction, P = 0.010) and fewer participants in the exercise training group met the functional disability criteria after anthracycline chemotherapy compared with those in the usual care group (7 vs. 50%, P = 0.01). Compared with the baseline, the peak exercise heart rate was higher and the stroke volume was lower after chemotherapy (P = 0.003 and P = 0.06, respectively). There was a reduction in resting LVEF (from 63 ± 5 to 60 ± 5%, P = 0.002) and an increase in troponin (from 2.9 ± 1.3 to 28.5 ± 22.4 ng/mL, P < 0.0001), but no difference was observed between the usual care and exercise training group. The baseline peak cardiac output was the strongest predictor of functional capacity after anthracycline chemotherapy in a model containing age and resting cardiac function (LVEF and global longitudinal strain).
Conclusions
The peak exercise cardiac output can identify patients at risk of chemotherapy-induced functional disability, whereas current clinical standards are unhelpful. Functional disability can be prevented with exercise training.