Renal effects of cardiopulmonary bypass in the elderly

Abstract

Cardiopulmonary bypass is widely believed to be injurious to renal function. The unknown consequences of renal dysfunction with modern techniques of bypass in the elderly caused us to examine creatinine clearance and the excretion of sensitive marker proteins in older adult patients undergoing CABG. Thirty male patients were divided into three groups: group I with an age up to 60 years, group II with an age between 61 and 70 years, inclusive and group III 71 years and over. Serum creatinine and urea, creatinine clearance, and α1-micro-globulin (α1-MG), N-acetyl-β-D-glucosaminidase (NAG), Tamm -Horsfall protein (TH) and immunoglobulin G (IgG) were all measured daily, pre- and postoperatively. Creatinine clearance remained lower in the older patients without significant differences. Raised excretion rates of α1-MG, and IgG were seen after CPB. The increase in α1- MG and NAG during the postoperative period revealed tubular damage in all elderly patients. Measurements of α1-MG, NAG and IgG represent useful supplements to standard clinical tests for recognizing early and differentiated changes in renal function.