Renal failure is a frequent event after cardiopulmonary by-pass. Hemodynamic alterations that occur during surgery, as well as factors depending on the host, are the main risk factors for renal dysfunction. To evaluate the frequency and risk factors for renal dysfunction in this setting, a cohort of fifty patients with preoperative serum creatinine under 1.5 mg/dL, submitted to cardiac surgery with cardiopulmonary by-pass was analyzed. Variables related to preoperative patient condition, intraoperative and postoperative periods were recorded. Renal function was assessed by clearances of creatinine, urea and free water, also by fractional excretion of sodium (FENa), at baseline, at anesthetic induction and during postoperative period. Patients were arbitrarily divided in two groups, according to the serum creatinine (S(Cr)) value at the end of the postoperative period: Group 1: S(Cr) < 2 mg/dL (n = 44 patients (88.5%)) and Group II: S(Cr) > 2 mg/dL (n = 6 patients (11.5%)). A decrease of renal function was observed in all patients: creatinemia raised from 1.04 +/- 0.2 to 1.55 +/- 0.4 mg/dL (33%), associated with a rise in FENa. Differences between group I and group II using univariate analysis were: baseline serum creatinine (1.01 +/- 0.23 mg/dL vs. 1.26 +/- 0.19 mg/dL, p = 0.03), FENa (0.99 +/- 0.8 vs. 2.2 +/- 2.1, p = 0.04), furosemide dose during surgery normalized to body surface area (93.2 +/- 23 mg/1.73 m2 BSA vs. 135 +/- 38 mg/1.73 m2 BSA, p < 0.001), and hemodilution index (17.3 +/- 4.3% vs. 22.8 +/- 3.2%, p < 0.01). In the multiple regression model, baseline creatinemia and furosemide dose were associated to renal dysfunction.

Xenografting is increasingly being developed as a response to the shortage of human tissues. However, antigenic components of bone material eliciting immune responses--particularly of cellular nature--are blamed for the reduction of the osteoinductive properties of bone and bone-derived implants. The aim of our study was to compare the immunologic response and osteogenesis induced by antigen-depleted allogeneic and xenogeneic bone-derived implants to that induced by partially antigen-depleted material heterotopically placed (muscular pouch) in rats. Wistar rats received bone-derived implants of different antigeneic condition, from both xenogeneic (rabbit) and allogeneic (rat) origin. After sacrifice, animals were evaluated for osteogenesis and immune response. New bone formation was observed around all bone-derived implants, whether fully or partially antigen-extracted, and from both xenogeneic and allogeneic origin. No significant humoral response resulted following bone implantation. Cellular response showed a similar pattern in partial and fully antigen-extracted bone of both allogeneic and xenogeneic origin. Xenogeneic antigen-extracted bone from safe donor sources could be a suitable solution to human tissue shortage in a near future.