Objective: Cardiac toxicity remains an important side effect of anthracyclines. New drug formulations (eg, pegylated liposomal doxorubicin [PL-DOX]) seem to be a successful strategy for reducing it. Changes in cardiac function induced by early chemotherapy, however, are subtle and difficult to quantitate by conventional imaging methods. Doppler myocardial imaging-based velocity, strain, and strain rate measurements have been shown to sensitively quantify abnormalities in cardiac function in other settings.
Design: We evaluated the feasibility and sensitivity of strain rate imaging compared with conventional echocardiography in detecting cardiac effects of PL-DOX therapy in elderly patients with cancer. In a pilot study, we examined 16 elderly women (age 69.8 +/- 3.1 years) with breast cancer receiving 6 cycles of PL-DOX. Conventional and Doppler myocardial imaging echocardiography were obtained at baseline and after 3 and 6 cycles of treatment. Segmental peak systolic longitudinal and radial velocity, strain, and strain rate were measured.
Results: Left ventricular dimensions, ejection fraction, and systolic myocardial velocity did not change throughout the follow-up. In contrast, a significant reduction in longitudinal and radial strain and strain rate was found after 6 cycles (longitudinal strain -18.8% +/- 2.8% vs -22.7% +/- 2.8%, P < .001 vs baseline and P = .001 vs after 3 cycles; radial strain 32.3% +/- 8.1% vs 50.1% +/- 11.6%, P < .001 vs baseline). Changes in radial function appeared earlier and were more pronounced than in longitudinal direction.
Conclusion: In contrast with conventional echocardiography and myocardial velocity measurements, myocardial deformation parameters allowed detecting subtle changes in longitudinal and radial left ventricular function after 6 cycles of PL-DOX. We suggest that Doppler-based myocardial deformation imaging should be used for cardiac function monitoring during chemotherapy.