['High concentrations of fibroblast growth factors (FGFs) are found in the heart. Even higher levels are measured during ischemia. Exogenous administration of FGF to ischemic myocardium promotes synthesis of collateral coronary circulation and induces local myocardial hypertrophy. The kinetics and the contribution of the heart and lungs to circulating basic FGF (bFGF) levels during cardiac surgery were characterized.', 'Plasma bFGF levels were measured in seven adults undergoing coronary artery bypass operations and 11 neonates undergoing congenital cardiac anomaly repair during cardiopulmonary bypass.', 'In both the adult and the neonatal groups, bFGF plasma levels increased significantly immediately after removal of the aortic cross-clamp (adult 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 coronary 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 significantly higher than the peripheral measurements.'] Are increased levels of basic fibroblast growth factor found in the cross-clamped heart during cardiopulmonary bypass?