Longitudinal evaluation of cardiopulmonary performance during exercise after bone marrow transplantation in children

Objective: Abnormalities in cardiopulmonary performance during exercise hav e been reported in children after bone marrow transplantation (BMT). We sou ght to study changes in exercise performance over time in pediatric BMT sur vivors. Study design: We retrospectively reviewed the results of serial cardiopulmo nary exercise tests performed by patients who had undergone BMT at our inst itution. Four measurements of cardiopulmonary function are reported: maximu m cardiac index (MCI), maximal oxygen consumption (Max VO2), oxygen consump tion at ventilatory threshold (VO2 at VT), and maximum work (Max Work) perf ormed. A linear mixed-effects model was fitted to assess changes in these p arameters over time. Results: Thirty-three patients performed 96 cardiopulmonary exercise tests. MCI and VO2 at VT were depressed at initial testing and did not change ove r time. Max VO2 increased by 4% per year to 69% predicted, and Max Work inc reased to 77% predicted at 6 years after BMT. Conclusions: In spite of an impaired cardiovascular response to exercise as indicated by the persistently low MCI, aerobic and physical working capaci ty increase. Improved Max VO2 suggests that oxygen extraction at the muscul oskeletal level becomes more efficient with recovery from BMT, This may rep resent a compensatory response to an impaired ability to increase cardiac o utput.