Increased levels of basic fibroblast growth factor are found in the cross-clamped heart during cardiopulmonary bypass

BACKGROUND: High concentrations of fibroblast growth factors (FGFs) are fou nd in the heart. Even higher levels are measured during ischemia. Exogenous administration of FGF to ischemic myocardium promotes synthesis of collate ral coronary circulation and induces local myocardial hypertrophy. The kine tics and the contribution of the heart and lungs to circulating basic FGF ( bFGF) levels during cardiac surgery were characterized. PATIENTS AND METHODS: Plasma bFGF levels were measured in seven adults unde rgoing coronary artery bypass operations and 11 neonates undergoing congeni tal cardiac anomaly repair during cardiopulmonary bypass. RESULTS: In both the adult and the neonatal groups, bFGF plasma levels incr eased significantly immediately after removal of the aortic cross-clamp (ad ult group 15.43 +/- 6.3 aorta cross clamped versus 29 +/- 4.1 after release , P = 0.011; neonatal group 17.09 +/- 9.43 aorta cross-clamped versus 43.55 +/- 14.25 after release, P = 0.004) and declined thereafter. In the adult group, higher levels of bFGF were recorded in blood recovered from the coro nary sinus than in the aortic root during aortic cross clamping (63.14 +/- 14.42 versus 43.86 +/- 12.05, P = 0.011), and in both, levels were signific antly higher than the peripheral measurements. CONCLUSIONS: Plasma bFGF levels increase during cardiopulmonary bypass. The source of this elevation is the lungs and heart.