A method for detection of doxorubicin-induced cardiotoxicity: Flow-mediated vasodilation of the brachial artery

The cardiotoxicity of anthracyclin antibiotics such as doxorubicin (DOX) is a serious side effect in cancer therapy. Reduced antioxidant capacity may be a factor responsible for DOX-induced oxidative damage to the heart. The endothelial dysfunction that results from excessive free radicals can be easily detected by flow-mediated vasodilation (FMD) of the brachial artery.

To determine the change in endothelial function after intravenous DOX bolus; to determine the change in biochemical parameters, reflecting increased activity of free radicals or decreased endogenous antioxidant capacity, after intravenous DOX bolus; and to determine the relation between alteration of en-dothelial function after the first DOX bolus and the change in left ventricular function during follow-up.

Twenty-two patients, with either non-Hodgkin's lymphoma (18 patients) or Hodgkin's disease (four patients) were enrolled for the study (seven women and 15 men), with a mean age of 37.3+/-13.7 years. Each patient was treated with a DOX-containing regimen. The actual mean dose of DOX was 33+/-12 mg/m(2). FMD was evaluated before and after DOX administration. In nine patients more frequent measures were taken to determine the time course of change in FMD after DOX administration. FMD was measured 6, 12, 24 and 48 h after DOX. On average each patient was followed up for 18.6+/-8.1 months following the first DOX administration. The mean cumulative DOX dose was 229+/-112 mg/m(2) by the end of the follow-up period. Left ventricular ejection fraction was determined regularly during and at the end of the study.

FMD was normal (more than 5%) at baseline in each patient but decreased significantly after DOX bolus (9.9+/-4.4% versus 6.1+/-4.6%, P<0.02). Marked individual differences were found in FMD changes after DOX. Patients who had a more than 5% decrease in FMD after DOX bolus were pretreated with 1000 mg of vitamin C intravenously, just before the next intravenous bolus of DOX was given. The decrease in FMD was prevented. Stepwise multiple regression analysis showed that the decrease in left ventricular ejection fraction during follow-up significantly and independently correlated with the cumulative DOX dose and the value of FMD alteration after the first DOX bolus administration.

FMD in the brachial artery was significantly impaired after the first DOX bolus. The marked individual differences suggest different antioxidant capacities in these patients. The results suggest that alterations in FMD after DOX allows for detection of patients with insufficient antioxidant capacity and patients at a higher risk of DOX-induced cardiotoxicity.