Edward J. Alfrey

Randomized trial of tacrolimus + mycophenolate mofetil or azathioprine versus cyclosporine + mycophenolate mofetil after cadaveric kidney transplantation : Results at three years

Methods. Two hundred twenty-three recipients of first cadaveric kidney allografts were randomized to receive tacrolimus (TAC) + mycophenolate mofetil (MMF), TAC + azathioprine (AZA), or cyclosporine (Neoral; CsA) + MMF. All regimens contained corticosteroids, and antibody induction was used only in patients who experienced delayed graft function (DGF). Patients were followed-up for 3 years. Results. The results at 3 years corroborate and extend the findings of the 2-year results. Patients with DGF treated with TAC+MMF experienced an increase in 3-year allograft survival compared with patients receiving CsA+MMF (84.1% vs. 49.9%, P =0.02). Patients randomized to either treatment arm containing TAC exhibited numerically superior kidney function when compared with CsA. During the 3 years, new-onset insulin dependence occurred in 6, 3, and 11 patients in the TAC+MMF, CsA+MMF, and TAC+AZA treatment arms, respectively. Furthermore, patients randomized to TAC+MMF received significantly lower doses of MMF as compared with those who received CsA+MMF. Conclusion. All three immunosuppressive regimens provided excellent safety and efficacy. However, the best results overall were achieved with TAC+MMF. The combination may provide particular benefit to kidney allograft recipients with DGF. In patients who experienced DGF, graft survival was better at 3 years in those patients receiving TAC in combination with either MMF or AZA as compared with the patients receiving CsA with MMF.

Backleak, tight junctions, and cell- cell adhesion in postischemic injury to the renal allograft.

Postischemic injury in recipients of 3-7-d-old renal allografts was classified into sustained (n = 19) or recovering (n = 20) acute renal failure (ARF) according to the prevailing inulin clearance. Recipients of optimally functioning, long-standing allografts and living donors undergoing nephrectomy served as functional (n = 14) and structural controls (n = 10), respectively. Marked elevation above control of fractional clearance of dextrans of graded size was consistent with transtubular backleak of 57% of filtrate (inulin) in sustained ARF. No backleak was detected in recovering ARF. To explore a structural basis for backleak, allograft biopsies were taken intraoperatively, 1 h after reperfusion in all recipients, and again on day 7 after transplant in a subset (n = 10). Electron microscopy revealed disruption of both apical and basolateral membranes of proximal tubule cells in both sustained and recovering ARF, but cell exfoliation and tubule basement membrane denudation were negligible. Histochemical analysis of membrane-associated adhesion complexes confirmed an abnormality of proximal but not distal tubule cells, marked in sustained ARF but not in recovering ARF. Staining for the zonula occludens complex (ZO-1) and adherens complex (alpha, beta, and gamma catenins) revealed diminished intensity and redistribution of each cytoskeletal protein from the apico-lateral membrane boundary. We conclude that impaired integrity of tight junctions and cell-cell adhesion in the proximal tubule provides a paracellular pathway through which filtrate leaks back in sustained allograft ARF.

Mechanisms of filtration failure during postischemic injury of the human kidney. A study of the reperfused renal allograft.

Postischemic filtration failure in experimental animals results primarily from depression of the transcapillary hydraulic pressure difference (delta P), a quantity that cannot be determined in humans. To circumvent this limitation we determined the GFR and each of its remaining determinants in transplanted kidneys. Findings in 12 allografts that exhibited subsequent normofiltration (group 1) were compared with those in 11 allografts that exhibited persistent hypofiltration (group 2). Determinations were made intraoperatively in the exposed graft after 1-3 h of reperfusion. GFR (6 +/- 2 vs 29 +/- 5 ml/min) and renal plasma flow by Doppler flow meter (140 +/- 30 vs 315 +/- 49 ml/min) were significantly lower in group 2 than group 1. Morphometric analysis of glomeruli obtained by biopsy and a structural hydrodynamic model of viscous flow revealed the glomerular ultrafiltration coefficient to be similar, averaging 3.5 +/- 0.6 and 3.1 +/- 0.2 ml/(min.mmHg) in group 2 vs 1, respectively. Corresponding values for plasma oncotic pressure were also similar, averaging 19 +/- 1 vs 21 +/- 1 mmHg. We next used a mathematical model of glomerular ultrafiltration and a sensitivity analysis to calculate the prevailing range for delta P from the foregoing measured quantities. This revealed delta P to vary from only 20-21 mmHg in group 2 vs 34-45 mmHg in group 1 (P < 0.001). Further morphometric analysis revealed the diameters of Bowmans space and tubular lumens, as well as the percentage of tubular cells that were necrotic or devoid of brush border, to be similar in the two groups. We thus conclude (a) that delta P depression is the predominant cause of hypofiltration in this form of postischemic injury; and (b) that afferent vasoconstriction rather than tubular obstruction is the proximate cause of the delta P depression.

Successful transplantation of adult-sized kidneys into infants requires maintenance of high aortic blood flow.

BACKGROUND Nationally, results of renal transplantation in infants are inferior to those in older children and adults. Within the infant group, best results are obtained with adult-sized kidneys (ASKs) rather than size-compatible pediatric kidneys. However, transplantation of ASKs into infants has an increased risk of acute tubular necrosis and graft loss from vascular thrombosis and primary nonfunction. The aim of this study was to define and understand the hemodynamic changes induced by ASK transplantation, so that outcomes of transplantation in infants can be improved. METHODS Nine hemodynamically stable and optimally hydrated infants were studied under a controlled sedation with cine phase-contrast magnetic resonance at three time periods: before transplantation, 8-12 days after transplantation, and 4-6 months after transplantation. Cross-sectional images of both the infant aorta and the adult transplant renal artery were obtained and blood flow was quantitated. Renal volumes were also obtained, and expected renal artery blood flow based on early posttransplant volume was calculated. In addition, renal artery blood flow was determined in 10 in situ native adult kidneys prior to donor nephrectomy. Supplemental nasogastric or gastrostomy tube feeding was carried out during the blood flow study period to optimize intravascular volume. RESULTS Mean infant aortic blood flows were 331+/-148 ml/min before transplantation, 761+/-272 ml/ min at 8-12 days after transplantation (P=0.0006 with pretransplant flow), and 665+/-138 ml/min at 4-6 months after transplantation (P=0.0001 with pretransplant flow). Mean transplanted renal artery flows were 385+/-158 ml/min at 8-12 days and 296+/-113 ml/min at 4-6 months after transplantation. Transplanted renal artery flows were less than prenephrectomy in situ donor renal artery blood flow (618+/-130 ml/min; P=0.02 and P=0.0003) and expected normal renal artery blood flow (666+/-87 ml/min; P=0.003 and P=0.001) at both 8-12 days and 4-6 months after transplantation. A 26% reduction in renal volume (P=0.003) occurred between the two postoperative time periods, and this paralleled the decrease in posttransplant renal artery flow. One-year graft and patient survival in the nine infants was 100%. The mean serum creatinine levels at 3, 6, and 12 months were 0.43+/-0.10, 0.48+/-0.15, and 0.49+/-0.16 mg/dl. CONCLUSIONS This study is the first to quantitatively document the blood flow changes occurring after ASK transplantation in infants. There was a greater than two-fold increase in aortic blood flow after ASK transplantation, and this increase was sustained for at least 4 months and appeared to be driven by the blood flow demand of the ASK. However, actual posttransplant renal artery blood flow was significantly less than normal renal artery flow. Our study suggests that aggressive intravascular volume maintenance may be necessary to achieve and maintain optimum aortic blood flow, so as not to further compromise posttransplant renal artery flow and to avoid low-flow states that could induce acute tubular necrosis, vascular thrombosis, or primary nonfunction.

Evaluation of the older cadaveric kidney donor: the impact of donor hypertension and creatinine clearance on graft performance and survival.

Background. The use of older donors for cadaveric renal transplantation (CRT) remains controversial because older donors are associated with decreased graft survival, yet offer the opportunity for donor pool expansion.We investigated the impact of two age-related donor factors, hypertension and calculated creatinine clearance (C Cr), as predictors of graft outcome in recipients of CRTs from donors ≥55 years of age. Methods. We reviewed 33,595 recipients of CRTs reported to UNOS since 4/1/94, of which 4,732 were from donors aged ≥55 years. Outcome measures were graft survival, serum creatinine, and incidence of delayed graft function with 3 years of follow-up. We first analyzed the effect of hypertension on outcome from donors ≥55 years: 2679 donors had no hypertension, 1058 had hypertension ≤10 years, and 557 had hypertension >10 years. Next, the effect of donor C Cr as a risk predictor was investigated. Based on this analysis, recipients of older donors were grouped into two cohorts for comparison: 2570 donors with C Cr <80 ml/min and 2162 donors with C Cr ≥80 ml/min. Results. Actuarial graft survival from donors aged <55 years was 88.0, 83.4, and 78.5% at 1, 2, and 3 years, vs. 80.6, 73.5, and 65.3% from donors ≥55 years (P <0.0001). When stratified by hypertension, older donors hypertensive >10 years had survivals of 77, 66, and 57% vs. 81, 73, and 65% from donors without hypertension (P <0.017) and 80, 74, and 66% from donors hypertensive <10 years (P <0.017). When stratified by C Cr, older donors with C Cr <80 ml/min had survivals of 77, 69, and 62% vs. 83, 76, and 66% from donors with C Cr ≥80 (P <0.0001). Finally, older donors with both hypertension >10 years and C Cr <80 ml/min had survivals of 77, 61, and 53%. Conclusions. Long-standing hypertension and low calculated creatinine clearance are risk factors for decreased graft survival of CRTs from older donors. When both factors are present, graft survival is significantly decreased.

The use of bilateral adult renal allografts - a method to optimize function from donor kidneys with suboptimal nephron mass.

Alternatives to traditional organ donor usage has allowed expansion of the organ donor pool to help compensate for the increasing disparity between recipients and donors. The use of bilateral adult renal transplants is a novel idea to salvage older donor kidneys with suboptimal nephron mass that would otherwise be destined for discard. Ten renal transplants were performed utilizing both kidneys from adult cadaver donors with diminished nephron mass determined by calculated glomerular filtration rate or biopsy evidence of significant glomerulosclerosis (>10%). Nine of ten (90%) recipients have satisfactory renal function at a mean follow-up of 7 months. The single case of graft failure was due to documented medical non-compliance. Mean serum creatinine at 6 months was 1.5 mg/dl. Mean measured creatinine clearance was 43.2+/-3.4. These preliminary findings suggest that the use of bilateral renal transplants provide satisfactory early function and allows salvage of older donor kidneys with suboptimal nephron mass.

Resident versus no resident: a single institutional study on operative complications, mortality, and cost.

BACKGROUND Previous studies have demonstrated an increase in surgical morbidity, mortality, duration of stay, and costs in teaching hospitals. These studies are confounded by many variables. Controlling for these variables, we studied the effect of surgical residents on these outcomes during rotations with non-academic-based teaching faculty at a teaching hospital. METHODS Patients received care at a single teaching hospital from a group of 8 surgeons. Four surgeons did not have resident coverage (group 1) and the other 4 had coverage (group 2). Continuous severity adjusted complications, mortality, length of stay, cost, and hospital margin data were collected and compared. RESULTS Five common procedures were examined: bowel resection, laparoscopic cholecystectomy, hernia, mastectomy, and appendectomy. Comparing all procedures together, there were no differences in complications between the groups, although there was greater mortality, a greater duration of stay, and higher costs in group 2. When comparing the 5 most common procedures individually, there was no difference in complications or mortality, although a greater length of stay and higher costs in group 2. CONCLUSIONS Comparing the most common procedures performed individually, patients cared for by surgeons with surgical residents at a teaching hospital have an increase in duration of stay and cost, although no difference in complications or mortality compared to surgeons without residents.

When should expanded criteria donor kidneys be used for single versus dual kidney transplants

BACKGROUND To increase the utilization of cadaveric donor kidneys, we have recently expanded our acceptable criteria to include aged donors (frequently with a history of hypertension), by selectively using both donor kidneys (dual transplant) into a single recipient. METHODS To define when these expanded criteria donor (ECD) kidneys should be used as a single versus a dual kidney transplant, we retrospectively reviewed 52 recipients of ECD kidneys that had been turned down by all other local centers between 1/1/95 and 11/15/96. Fifteen patients received dual transplants, whereas the remaining 37 received single kidneys. Of the dual kidney recipients, 14 of 15 ECD were > or = 59 years of age, 10 of 15 were hypertensive, and 9 of 15 were both. Of the single recipients, 11 of 37 ECD were > or = 59 years of age, 11 of 37 were hypertensive, and 7 of 37 were both. All patients received cyclosporine-based triple-drug therapy. We compared seven donor (D) and sixteen recipient outcome variables in single versus dual kidney transplants as subgrouped by: (1) donor admission creatinine clearance (D-AdC(Cr)) < 90 ml/min; (2) D-age > or = 59 years; and (3) cold storage (Cld Stg) < or > 24 hr. RESULTS In the group with D-AdC(Cr) < 90, there was a significantly higher incidence of delayed graft function (DGF) in single versus dual recipients (9 of 20 [45%] vs. 1 of 11 [9%]; P=0.04) and worse early graft function based upon mean serum creatinine at 1 and 4 weeks (5.3+/-3.3 and 2.8+/-2.0 vs. 1.7+/-0.6 and 1.4+/-0.5 mg] dl; P<0.05). In the group with D-age > or = 59, recipients of single kidneys had significantly higher mean serum creatinine at 1, 4, and 12 weeks versus recipients of dual kidneys (5.1+/-3.3, 3.4+/-2.1, 2.8+/-1.5 versus 2.8+/-2.5, 1.5+/-0.6, 1.6+/-0.5 mg/dl; P<0.05). Cld Stg time also had an impact on DGF and early outcome. Recipients of dual kidneys stored less than 24 hr had a significantly lower incidence of DGF versus single kidneys stored more than 24 hr (10% vs. 46%; P<0.05) and better early graft function based on mean serum creatinine at 1, 4, and 12 weeks (1.9+/-0.8, 1.3+/-0.4, 1.5+/-0.2 vs. 6.6+/-3.4, 3.0+/-1.6, 2.9+/-1.9 mg/dl; P<0.05). The overall 1-year patient and graft survivals were 96% and 81% vs. 93% and 87% (P=NS) in recipients of single ECD versus dual ECD kidneys. CONCLUSIONS In conclusion, we believe that kidneys from ECD with D-AdC(Cr) < 90 ml/min and D-age > or = 59 should be used as dual kidney transplants, keeping the Cld Stg time at < 24 hr to minimize the effect of Cld Stg on early graft function.

Dual-kidney transplantation with organs from expanded criteria donors: a long-term follow-up.

Background. Since 1995, dual-kidney transplantation using organs from marginal donors has been used at our center to expand the organ donor pool and decrease the waiting time for deceased donor kidney transplantation. This approach has allowed for a shorter waiting period without compromising outcome in the early posttransplant period. We now have 8-year follow-up in the first recipients. Older individuals were offered this option preferentially, because we reasoned that they would stand to benefit most from the shorter waiting period. Methods. Patients aged 55 years or more who underwent either dual-kidney transplantation with expanded criteria donors or single-kidney transplantation with standard donors were included in this study. All expanded criteria donor organs were those that were refused by all other local transplant centers. The primary endpoints were recipient death and graft failure. Results. Waiting time for dual-kidney transplantation was 440±38 days versus 664±51 days for single-kidney transplantation (P<0.01). The 8-year actuarial patient survivals for the single- and dual-kidney transplants were 74.1% and 82.1%, respectively. The 8-year actuarial graft survivals for the single- and dual-kidney transplants were 59.4% and 69.7%, respectively. Conclusions. Eight-year actuarial patient and graft survivals in older individuals who underwent dual-kidney transplantation are equivalent to those who underwent standard single-kidney transplantation. With the continuing organ shortage and increasing waiting times for cadaver kidney transplantation, dual-kidney transplantation using organs that would otherwise be discarded offers a good option for older individuals who may not withstand a long waiting period.

A recent decrease in the time to development of monomorphous and polymorphous posttransplant lymphoproliferative disorder.

&NA; We have noted a decrease in the time to development of posttransplant lymphoproliferative disorder (PTLD) over the last two and one-half years in our multiorgan transplant program. From February 1965 until December 1990, 1622 transplants were performed including 1489 kidneys (KTxp), 87 livers (LTxp), and 46 pancreata. Between February 1965 and July 1988 (group 1), there were 1260 transplants performed and nine cases of either monomorphous PTLD (M-PTLD, n=8) or polymorphous PTLD (P-PTLD, n=1) were diagnosed. The mean time to development of PTLD was 163±128 weeks, all after KTxp. Five of these nine patients received haploidentical living-related grafts. All patients had presented with advanced disease, none had transplant nephrectomy, and all died of their disease. Between July 1988 and December 1990 (group 2), 362 transplants were performed, and four cases of M-PTLD and three cases of P-PTLD were recognized. Of the seven cases of PTLD in group 2, six developed within 90 days posttransplant (early PTLD). The mean time to development of PTLD was 11±16 weeks. This was significantly earlier than group 1 (P<.01). Four of the five cases after KTxp had a 1 or 2 DR-matched donor. Five of these seven patients had serological evidence of recent Epstein-Barr Virus infection, and four of these five had received OKT3 and then developed early PTLD. In group 2, three patients are alive 7–15 months after KTxp nephrectomy, the remaining four have died. We hypothesize that risk factors for the development of PTLD may include heavy immunosuppression, including the use of OKT3, good DR matching, and active EBV infection. Treatment should include graft removal, if applicable, and reduction or cessation of immunosuppression.