Abstract 2424: Improvement Of Cardiopulmonary Exercise Capacity In Patients With Chronic Post-infarction Heart Failure (CHF) After Intracoronary Infusion Of Bone Marrow-derived Progenitor Cells (BMC)
Intracoronary (i.c.) infusion of BMC in patients (pts.) with CHF is associated with improvements in left ventricular ejection fraction (LVEF) and reduction of NT-proBNP serum-levels, especially in pts. with more severe heart failure. However, ist is unknown whether the modest improvements in cardiac function translate into an increase in cardiopulmonary exercise capacity. A total of 52 CHF-pts. performed cardiopulmonary exercise tests (CPET) according to a modified Bruce protocol before and 3 months after i.c. infusion of BMC into the infarct-related artery. Anaerobic threshold (AT) was determined by the v-slope method. Overall, pts. were 58±12 years old with a moderately impaired LVEF (mean 42±11%) and a median NYHA-class 2±0.75. NT-proBNP-serum levels were elevated (1007±154 pmol/ml). All pts. received chronic optimized medical therapy with betablockers, ACE-inhibitors and combined diuretics, which was kept constant during the study duration. Initial CPET revealed reduced peak oxygen uptake (peak VO2: 14.0 ml/min/kg), maximal oxygen Pulse (O2Pmax: 11.4 ml/beat) and oxygen uptake at AT (VO2AT: 10.9 ml/min/kg), whereas CO2-equivalents (EqCO2) were elevated (29.7). 3 months after therapy, repeated CPET showed an increase in peak VO2 (14.0±3.9 to 15.3±4.3 ml/min/kg, p=0.07), whereas VO2 AT (10.8±2.5 to 10.8±2.5 ml/min/kg, p= n.s.), O2Pmax (11.2 ± 3.1 to 12.0±3.3 ml/beat, p= n.s.) or EqCO2 (29.7±6.4 to 29.8±6.8, p= n.s.) remained unchanged. However, after dichotomizating the patient cohort according to the median of VO2max at baseline, pts. with lower initial VO2max showed a significant improvement in VO2max (12.8±1.5 to 13.5±2.7ml/min/kg, p= 0.03) and an improvement in VO2AT (9.1±1.8 to 9.5±2.2 ml/min/kg, p= ns), as well as a reduction of EqCO2 (34.7±7.1 to 33.8±8.0, p= ns). In contrast, pts. with initial VO2max > median did not show any significant improvements. These findings indicate that intracoronary BMC-therapy improves exercise capacity in CHF-patients with more advanced heart failure. Therefore, cardiopulmonary exercise testing might help to identify pts. more likely to derive functional benefit from intracoronary BMC administration.