Objective: Long-term survivors of asymptomatic children treated with anthracycline may have cardiac toxicity without clinical findings. The subclinical cardiac toxicity could be evaluated by dobutamine stress echocardiography (DSE) with exploring effective and safe doses of dobutamine.
Methods: Twenty asymptomatic survivors (mean age: 19.2+/-4.0 years) treated with cumulative dose of 282.1+/-125.9 mg/m2 of anthracycline were compared with 18 age-matched healthy volunteers. Total time completed this treatment was 10.2+/-2.2 years. This was a cross-sectional case-controlled study and patient and control groups were evaluated at the time of routine appointments. Echocardiographic studies were performed before and after each dobutamine infusion of 5, 10, 15, 20 microg/kg/min.
Statistical analysis: Mann-Whitney U test was used to evaluate the difference between the groups. ANOVA for repeated measurements test was used to compare each measurement of control and patients groups and Bonferroni posthoc test was used for correction.
Results: Hemodynamic changes are observed at the dobutamine doses of 15 microg/kg/min in the patient group. Before dobutamine infusion in the patient group only isovolumic relaxation and contraction times values were prolonged comparing to the control group. After the infusion of dobutamine ejection fraction, shortening fraction, left ventricular posterior wall thickening (%LVPWt), end-systolic wall stress (ESS), interventricular septum systolic thickening, left ventricular end-systolic and end-diastolic diameters, mitral acceleration (AT) and deceleration times values were deteriorated in the patient group compared to the control group (p=0.05 for all). The highest differences between the groups were observed in the %LVPWt, ESS and AT values at the end of test.
Conclusion: The DSE is an effective and safe method to demonstrate the late anthracycline cardiotoxicity. Echocardiographic evaluation should be made at rest and dobutamine dose of 20 microg/kg/min. In the early diagnosis of late cardiac toxicity; assessment of %LVPWt, AT and ESS values in addition to standard echocardiographic examination could be the guidance for early diagnosis of late cardiac toxicity.