Clinical, serum cardiac troponin T and echocardiographic evaluation for prediction of late doxorubicin cardiotoxicity

Abstract

9536 Background: To evaluate whether clinical signs or symptoms of congestive heart failure, serial assessment of systolic and diastolic cardiac function by low dose dobutamine stress echo (LDSE) and serum cardiac troponin T (cTnT) can predict doxorubicin (DOXO) cardiotoxicity. Methods: Twenty five patients with osteosarcoma enrolled in the Brazilian osteosarcoma treatment group study 2000, from january 2000 to may 2004, were studied with LDSE (>5μg/kg/min) before chemotherapy, 160 mg/m2 DOXO and after 160 mg/m2 DOXO. cTnT were measured before and during DOXO infusion. Cardiotoxicity was defined as shortening fraction (SF) less than 30% assessed by rest echo 1 to 6 months off chemotherapy. Group A comprised those without cardiotoxicity (16 patients, 10 male, 14.3 ± 4.7 years) whereas group B included those with a SF < 30% (9 patients, 6 male, 15.4 ± 3 years). Elevated serum cTnT was defined as seric levels above 0.01ng/ml. Results: Patients were submitted to a mean 3.4 LDSE and a mean of 32.5 serum cTnT. One patient (group B) presented clinical manifestation of cardiotoxicity. There was no statistical difference of elevated serum cTnT between the group B and group A (87.5% vs 46.2%; p=0,06). Left ventricular dimensions by M- MODE and transmitral Doppler inflow diastolic parameters were not significantly different between the two groups. Resting SF showed comparable values in both groups until cumulative doses of DOXO reached 160mg/m2, then the resting SF in group B was significant lower than group A (27% ± 2 and 34.1% ± 2, p<0.01). During dobutamine infusion, SF and ΔSF (dobutamine-rest) were significantly lower in group B as compared to group A at a DOXO dose 160mg/m2 (SF 36.1%±3,4 and ΔSF 2.1±2.3 vs. SF 45.2%±4.9 and ΔSF 9.4±3; p< 0.01 and p < 0.01) as well as at a DOXO dose > 160mg/m2 (30.3%±3 and 3.1±1.9 vs. 40.8%±5.9 and 7.2±4.2;p<0.01 and p<0.01). Conclusions: This study suggests that LDSE is more reliable than cTnT and clinical evaluation for predicting future subclinical cardiotoxicity,even at lower doxorubicin dose. No significant financial relationships to disclose.