Kidney-specific proteins in elderly patients undergoing cardiac surgery with cardiopulmonary bypass.
In cardiac surgery, acute renal failure (ARF) is more likely in elderly patients than in younger patients. We assessed whether kidney function is different between elderly and younger cardiac surgery patients by measuring kidney-specific proteins. Forty consecutive patients aged <60 yr and 40 patients aged >70 yr without preoperative kidney dysfunction undergoing elective cardiac surgery with cardiopulmonary bypass (CPB) were included. Creatinine clearance and fractional excretion of sodium, as well as urine concentrations of N-acetyl-beta-D-glucosaminidase, alpha-1-microglobulin, glutathione transferase-pi (GST-pi), and glutathione transferase-alpha (GST-alpha) were measured after induction of anesthesia, at the end of surgery, and at the first and second postoperative days (PODs) on the intensive care unit. Patients' ages were 54 +/- 4 and 77 +/- 3 yr, respectively. Preoperative creatinine concentrations were without significant differences between the two groups. Fractional excretion of sodium was significantly higher after bypass in the elderly than in the younger patients. Urine concentrations of all kidney-specific proteins increased after CPB in the elderly (e.g., GST-pi from 16.2 +/- 3.4 to 27.7 +/- 3.9 microg/L), whereas they remained almost unchanged in the younger patients. Concentrations of all kidney-specific proteins were significantly larger in the elderly than in the younger patients even at the second POD. Although none of our patients suffered ARF requiring dialysis, increased post-CPB urine concentrations of kidney-specific proteins in the elderly suggest discrete and transient alterations in kidney integrity in comparison with a younger patient population undergoing cardiac surgery.


CONCLUSIONS
Measurement of kidney-specific proteins demonstrated that patients >70 yr (mean, 77 +/- 3 yr) undergoing cardiac surgery with cardiopulmonary bypass had moderate and transient alterations in kidney integrity compared with patients aged <60 yr (mean, 54 +/- 4 yr). These abnormalities were not detected with standard measures of kidney function (e.g., creatinine concentrations).
Boldt
Joachim
J
*Department of Anesthesiology and Intensive Care Medicine and the †Clinic of Cardiac Surgery, Klinikum der Stadt Ludwigshafen, Ludwigshafen, Germany.
Brenner
Torsten
T
Lang
Johannes
J
Kumle
Bernhard
B
Isgro
Frank
F
D000118:Acetylglucosaminidase / Q000097:blood; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism; D000510:Alpha-Globulins / Q000378:metabolism; D015415:Biomarkers; D002315:Cardiopulmonary Bypass; D003404:Creatinine / Q000097:blood; D005260:Female; D005982:Glutathione Transferase / Q000097:blood; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D007674:Kidney Diseases / Q000097:blood; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D011183:Postoperative Complications / Q000097:blood; D011506:Proteins / Q000378:metabolism*; D018570:Risk Assessment
D000510:Alpha-Globulins; D015415:Biomarkers; D011506:Proteins; C016001:alpha-1-microglobulin; D003404:Creatinine; D005982:Glutathione Transferase; D000118:Acetylglucosaminidase