Assessment of cardiac and renal function in children immediately after open-heart surgery: the significance of a reduced radionuclide ejection fraction (postoperative ejection fraction).

Ventricular ejection fractions, calculated from radionuclide studies, and inulin clearance, were determined in 33 infants and children immediately after surgical repair of their congenital or rheumatic heart defects. Of these children, the seven whose surgery did not require a period of ischemic arrest served as controls. The immediate postoperative ejection fractions in the 26 children who did undergo a period of ischemic arrest were significantly less than their preoperative values (P less than or equal to 0.001), but this decline was not observed in the control group. Ejection fraction tended to be depressed, transiently, in children 3-5 h after open-heart surgery. Early postoperative ejection fraction was significantly related to aortic cross-clamp time even when controlling for preoperative ejection fraction (r = 0.74, n = 25, P less than or equal to 0.001). Some striking declines in ejection fraction were observed among children whose aortic cross-clamp time exceeded 42 min. The decline in ejection fraction was transient; late postoperative (greater than 1 week) ejection fraction was not significantly different from preoperative values. Though glomerular filtration rates (GFRs) were often above normal, they were significantly correlated with ejection fraction (r = 0.74, n = 19, P less than or equal to 0.01). The lower GFRs were associated with the lower early postoperative ejection fractions.