URINARY-EXCRETION OF THROMBOXANE AND MARKERS FOR RENAL INJURY IN PATIENTS UNDERGOING CARDIOPULMONARY BYPASS

Urinary excretion of selected markers for renal injury, as well as uri nary excretion rates of the thromboxane metabolite, 11-keto-thromboxan e B-2 (11k-TXB(2)), was studied in 36 male patients undergoing coronar y bypass surgery using cardiopulmonary bypass (CPB). In all patients, excretion of both tubular (N-acetyl-beta-D-glucosaminidase [beta NAG]; alpha(1)-microglobulin [alpha(1)-MG]) and glomerular markers (albumin [Alb]; transferrin [Trf]; immunoglobulin G [IgG]) sharply increased o n Day 1 after CPB, and they remained elevated throughout the observati on period of 5 days. Urinary excretion rates of 11k-TXB(2) markedly in creased on Day 1 after surgery, and they rapidly decreased thereafter. In 12 of the 36 patients, a temporary increase of serum creatinine le vels (>1.30 mg/dl) was noted following surgery. A positive correlation was found between serum creatinine levels and excretion of the tubula r enzyme beta NAG (r = 0.36; p < 0.05), but not between creatinine lev els and alpha(1)-MG or the glomerular markers. Furthermore, no correla tion between urinary excretion of 11k-TXB(2) and any of the urinary ma rkers for renal injury could be detected. Our data do not strengthen t he hypothesis that acute renal injury observed during CPB is related t o exaggerated thromboxane biosynthesis in these patients. Monitoring o f urinary markers for incipient renal damage, particularly excretion o f beta NAG, might be of additional diagnostic value for detection of o therwise subclinical renal injury in patients undergoing CPB.