Exercise training affects hemodynamics not cardiac function during anthracycline-based chemotherapy.

Introduction: Preclinical data demonstrate the potential for exercise training to protect against anthracycline-related cardiotoxicity, but this remains to be shown in humans.
Purpose: To assess whether exercise training during anthracycline-based chemotherapy for treatment of breast cancer affects resting cardiac function and hemodynamics.
Methods: In this prospective, non-randomized controlled study, 26 women who participated in aerobic and resistance training 3×/wk during chemotherapy were compared to 11 women receiving usual care. Two-dimensional echocardiography was performed before and 7-14 days after completion of anthracycline-based chemotherapy. Pre- and post-anthracycline cardiac function and hemodynamic variables were compared within each group with paired t-tests; the change was compared between groups using ANCOVA with adjustment for baseline values.
Results: Left ventricular longitudinal strain, volumes, ejection fraction, E/A ratio, and mass did not change in either group. Hemoglobin, hematocrit, and mean arterial pressure decreased significantly from baseline in both groups (all p < 0.05) with no differences between groups. Cardiac output increased in the usual care group only (+ 0.27 ± 0.24 L/min/m ² , p < 0.01), which differed significantly from the exercise group (p = 0.03). Systemic vascular resistance (SVR) decreased in both groups (usual care: - 444, p < 0.01; exercise: - 265, dynes/s/cm ⁵ , p = 0.01). However, the reduction in SVR was significantly attenuated in the exercise group (p = 0.03) perhaps due to a compensatory decrease in estimated vessel lumen radius.
Conclusion: Exercise training during anthracycline chemotherapy treatment had no effect on resting cardiac function but appeared to modify hemodynamic responses. Specifically, exercise training attenuated the drop in SVR in response to chemotherapy-related reductions in hematocrit potentially by increasing vessel lumen radius.