Endothelial function in long-term survivors of childhood acute lymphoblastic leukemia: Effects of a home-based exercise program

Abstract

The risk for cardiovascular disease (CVD) is increased in long-term survivors of childhood acute lymphoblastic leukemia (ALL). Chemotherapy may have direct toxic effects on vascular endothelium, potentially increasing the significance of endothelial dysfunction in the development of CVD in ALL survivors. Endothelial structure and function can be measured with carotid intima media thickness (IMT) and brachial flow mediated dilation (FMD). IMT and FMD are intermediate markers of CVD. We studied endothelial function and the effects of an exercise program on vascular endothelium in long-term survivors of childhood ALL. Twenty-one 16-30 year old long-term survivors of ALL (age at diagnosis ≤16 years) and 21 healthy controls were studied at baseline, and 17 of the ALL survivors participated in a 16 week home-based exercise program. IMT and FMD were studied before and after the exercise program. At baseline, the ALL survivors had impaired overall FMD response (FMDauc, P = 0.02). FMDmax(%) was 22% lower (P = 0.06) and FMD at 40 seconds 44% lower (P = 0.01) compared to healthy controls. After the exercise program, FMD at 40 seconds (P < 0.01) and IMT (P = 0.02) improved. The mean overall FMD response increased by 25% after the exercise program, but this change was not statistically significant (P = 0.27). Our results show that the excess burden of CVD morbidity in this population may possibly be alleviated by simple means. The importance of physical activity on the health of childhood ALL survivors should be emphasized. Longer, controlled studies are needed to confirm our findings.