Plasma and urinary levels of heart fatty acid-binding protein in patients undergoing cardiac surgery

To evaluate the clinical significance of the plasma and urinary levels of h eart fatty acid-binding protein (H-FABP) in patients undergoing cardiac sur gery, a prospective study was conducted. Ten patients undergoing coronary a rtery bypass grafting were enrolled. Blood samples for determination of pla sma H-FABP (pH-FABP), the MB isoenzyme of creatine kinase (CK-MB) and tropo nin-T (TnT), and urine samples for determination of urinary H-FABP (uH-FABP ) were collected serially. None of the patients had perioperative myocardia l infarction. The time to reach the peak level after aortic declamping was significantly (p<0.05) shorter for pH-FABP (1.4 +/- 0.5 h) than for CK-MB ( 2.5 +/- 0.5 h), TnT (6.6 +/- 1.3 h) or uH- FABP (3.0 +/- 0.6 h). Peak level s of pH-FABP correlated with those of CK-MB (r=0.51, p=0.04), TnT (r=0.60, p=0.03) and uH-FABP (r=0.61, p=0.03), and peak levels of uH-FABP correlated with CK-MB (r=0.57, p=0.04). Postoperative uH-FABP levels correlated inver sely with the left ventricular stroke work index (r=-0.63, p=0.04). This st udy demonstrated that H-FABP appears rapidly in plasma after reperfusion an d reaches its peak earlier than other available biochemical markers; it app ears also in urine and the levels correlated with cardiac function. Plasma and urinary H-FABP may be an early and sensitive biochemical marker for the diagnosis of myocardial injury in patients undergoing cardiac surgery.