Mitigating Racial and Sex Disparities in Access to Living Donor Kidney Transplantation: Impact of the Nation's Longest Single-center Kidney Chain

OBJECTIVE

In this study, we sought to assess likelihood of living donor kidney transplantation (LDKT) within a single-center kidney transplant waitlist, by race and sex, after implementation of an incompatible program.

SUMMARY BACKGROUND DATA

Disparities in access to LDKT exist among minority women and may be partially explained by antigen sensitization secondary to prior pregnancies, transplants, or blood transfusions, creating difficulty finding compatible matches. To address these and other obstacles, an incompatible LDKT program, incorporating desensitization and kidney paired donation, was created at our institution.

METHODS

A retrospective cohort study was performed among our kidney transplant waitlist candidates (n = 8895). Multivariable Cox regression was utilized, comparing likelihood of LDKT before (era 1: 01/2007-01/2013) and after (era 2: 01/2013-11/2018) implementation of the incompatible program. Candidates were stratified by race [white vs minority (nonwhite)], sex, and breadth of sensitization.

RESULTS

Program implementation resulted in the nation's longest single-center kidney chain, and likelihood of LDKT increased by 70% for whites [adjusted hazard ratio (aHR) 1.70; 95% confidence interval (CI), 1.46-1.99] and more than 100% for minorities (aHR 2.05; 95% CI, 1.60-2.62). Improvement in access to LDKT was greatest among sensitized minority women [calculated panel reactive antibody (cPRA) 11%-49%: aHR 4.79; 95% CI, 2.27-10.11; cPRA 50%-100%: aHR 4.09; 95% CI, 1.89-8.82].

CONCLUSIONS

Implementation of an incompatible program, and the resulting nation's longest single-center kidney chain, mitigated disparities in access to LDKT among minorities, specifically sensitized women. Extrapolation of this success on a national level may further serve these vulnerable populations.

Landscape of ABO-Incompatible Live Donor Kidney Transplantation in the US

BACKGROUND

Widespread implementation of ABO-incompatible (ABOi) living donor kidney transplantation (LDKT) has been proposed as a means to partially ameliorate the national shortage of deceased donor kidneys. Acceptance of this practice has been encouraged by reports from experienced centers demonstrating acute rejection (AR) rates similar to those obtained with ABO-compatible (ABOc) LDKT. Acute rejection rate and graft survival after ABOi LDKT on a national level have yet to be fully determined.

STUDY DESIGN

We studied adult (>18 years) LDKT recipients, from 2000 to 2015, reported to the Scientific Registry of Transplant Recipients. Acute rejection rates in the first post-transplant year (modified Poisson regression) and graft survival (Cox proportional hazards) were assessed by ABO compatibility status (ABOi: 930; ABOc: 89,713).

RESULTS

Patients undergoing ABOi LDKT had an AR rate of 19.4% compared with 10.5% for ABOc recipients (p < 0.0001). After adjusting for recipient- and donor-related risk factors, patients undergoing ABOi LDKT were found to have a 1.76-fold greater risk for AR within 1 year of transplantation compared with ABOc LDKT recipients (adjusted relative risk [aRR] 1.76; 95% CI 1.54 to 2.01). Moreover, there was a 2.34-fold greater risk of death-censored graft loss at 1-year post-transplant among ABOi vs ABOc LDKT recipients (adjusted hazard ratio [aHR] 2.34; 95% CI 1.85 to 2.96).

CONCLUSIONS

Based on these findings, the low rates of AR and excellent short-term graft survival presented in single center series may not be sustainable on a national level. These findings highlight the potential utility for identification of centers of excellence and regionalization of ABOi LDKT.

Preoperative arterial microcalcification and clinical outcomes of arteriovenous fistulas for hemodialysis

BACKGROUND

Arteriovenous fistulas (AVFs) often fail to mature, but the mechanism of AVF nonmaturation is poorly understood. Arterial microcalcification is common in patients with chronic kidney disease (CKD) and may limit vascular dilatation, thereby contributing to early postoperative juxta-anastomotic AVF stenosis and impaired AVF maturation. This study evaluated whether preexisting arterial microcalcification adversely affects AVF outcomes.

STUDY DESIGN

Prospective study.

SETTING & PARTICIPANTS

127 patients with CKD undergoing AVF surgery at a large academic medical center.

PREDICTORS

Preexisting arterial microcalcification (≥1% of media area) assessed independently by von Kossa stains of arterial specimens obtained during AVF surgery and by preoperative ultrasound.

OUTCOMES

Juxta-anastomotic AVF stenosis (ascertained by ultrasound obtained 4-6 weeks postoperatively), AVF nonmaturation (inability to cannulate with 2 needles with dialysis blood flow ≥ 300mL/min for ≥6 sessions in 1 month within 6 months of AVF creation), and duration of primary unassisted AVF survival after successful use (time to first intervention).

RESULTS

Arterial microcalcification was present by histologic evaluation in 40% of patients undergoing AVF surgery. The frequency of a postoperative juxta-anastomotic AVF stenosis was similar in patients with or without preexisting arterial microcalcification (32% vs 42%; OR, 0.65; 95% CI, 0.28-1.52; P=0.3). AVF nonmaturation was observed in 29%, 33%, 33%, and 33% of patients with <1%, 1% to 4.9%, 5% to 9.9%, and ≥10% arterial microcalcification, respectively (P=0.9). Sonographic arterial microcalcification was found in 39% of patients and was associated with histologic calcification (P=0.001), but did not predict AVF nonmaturation. Finally, among AVFs that matured, unassisted AVF maturation (time to first intervention) was similar for patients with and without preexisting arterial microcalcification (HR, 0.64; 95% CI, 0.35-1.21; P=0.2).

LIMITATIONS

Single-center study.

CONCLUSIONS

Arterial microcalcification is common in patients with advanced CKD, but does not explain postoperative AVF stenosis, AVF nonmaturation, or AVF failure after successful cannulation.

Preoperative venous intimal hyperplasia, postoperative arteriovenous fistula stenosis, and clinical fistula outcomes

BACKGROUND AND OBJECTIVES

Arteriovenous fistulas often fail to mature, and nonmaturation has been attributed to postoperative stenosis caused by aggressive neointimal hyperplasia. Preexisting intimal hyperplasia in the native veins of uremic patients may predispose to postoperative arteriovenous fistula stenosis and arteriovenous fistula nonmaturation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This work explored the relationship between preexisting venous intimal hyperplasia, postoperative arteriovenous fistula stenosis, and clinical arteriovenous fistula outcomes in 145 patients. Venous specimens obtained during arteriovenous fistula creation were quantified for maximal intimal thickness (median thickness=22.3 μm). Postoperative ultrasounds at 4-6 weeks were evaluated for arteriovenous fistula stenosis. Arteriovenous fistula maturation within 6 months of creation was determined clinically.

RESULTS

Postoperative arteriovenous fistula stenosis was equally frequent in patients with preexisting venous intimal hyperplasia (thickness>22.3 μm) and patients without hyperplasia (46% versus 53%; P=0.49). Arteriovenous fistula nonmaturation occurred in 30% of patients with postoperative stenosis versus 7% of those patients without stenosis (hazard ratio, 4.33; 95% confidence interval, 1.55 to 12.06; P=0.001). The annual frequency of interventions to maintain arteriovenous fistula patency for dialysis after maturation was higher in patients with postoperative stenosis than patients without stenosis (0.83 [95% confidence interval, 0.58 to 1.14] versus 0.42 [95% confidence interval, 0.28 to 0.62]; P=0.008).

CONCLUSIONS

Preexisting venous intimal hyperplasia does not predispose to postoperative arteriovenous fistula stenosis. Postoperative arteriovenous fistula stenosis is associated with a higher arteriovenous fistula nonmaturation rate. Arteriovenous fistulas with hemodynamically significant stenosis frequently mature without an intervention. Postoperative arteriovenous fistula stenosis is associated with an increased frequency of interventions to maintain long-term arteriovenous fistula patency after maturation.

Correlation of pre-existing vascular pathology with arteriovenous graft outcomes in hemodialysis patients

BACKGROUND

Arteriovenous grafts (AVGs) are prone to neointimal hyperplasia leading to AVG failure. We hypothesized that pre-existing pathologic abnormalities of the vessels used to create AVGs (including venous intimal hyperplasia, arterial intimal hyperplasia, arterial medial fibrosis, and arterial calcification) are associated with inferior AVG survival.

STUDY DESIGN

Prospective observational study.

SETTING & PARTICIPANTS

Patients with chronic kidney disease undergoing placement of a new AVG at a large medical center who had vascular specimens obtained at the time of surgery (n = 76).

PREDICTOR

Maximal intimal thickness of the arterial and venous intima, arterial medial fibrosis, and arterial medial calcification.

OUTCOME & MEASUREMENTS

Unassisted primary AVG survival (time to first intervention) and frequency of AVG interventions.

RESULTS

55 patients (72%) underwent interventions and 148 graft interventions occurred during 89.9 years of follow-up (1.65 interventions per graft-year). Unassisted primary AVG survival was not associated significantly with arterial intimal thickness (HR, 0.72; 95% CI, 0.40-1.27; P = 0.3), venous intimal thickness (HR, 0.64; 95% CI, 0.37-1.10; P = 0.1), severe arterial medial fibrosis (HR, 0.58; 95% CI, 0.32-1.06; P = 0.6), or severe arterial calcification (HR, 0.68; 95% CI, 0.37-1.31; P = 0.3). The frequency of AVG interventions per year was associated inversely with arterial intimal thickness (relative risk [RR], 1.99; 95% CI, 1.16-3.42; P < 0.001 for thickness <10 vs. >25 μm), venous intimal thickness (RR, 2.11; 95% CI, 1.39-3.20; P < 0.001 for thickness <5 vs. >10 μm), arterial medial fibrosis (RR, 3.17; 95% CI, 1.96-5.13; P < 0.001 for fibrosis <70% vs. ≥70%), and arterial calcification (RR, 2.12; 95% CI, 1.31-3.43; P = 0.001 for <10% vs. ≥10% calcification).

LIMITATIONS

Single-center study. Study may be underpowered to demonstrate differences in unassisted primary AVG survival.

CONCLUSIONS

Pre-existing vascular pathologic abnormalities in patients with chronic kidney disease may not be associated significantly with unassisted primary AVG survival. However, vascular intimal hyperplasia, arterial medial fibrosis, and arterial calcification may be associated with a decreased frequency of AVG interventions.

Medial fibrosis, vascular calcification, intimal hyperplasia, and arteriovenous fistula maturation

BACKGROUND

Arteriovenous fistulas (AVFs) for hemodialysis frequently fail to mature because of inadequate dilation or early stenosis. The pathogenesis of AVF nonmaturation may be related to pre-existing vascular pathologic states: medial fibrosis or microcalcification may limit arterial dilation, and intimal hyperplasia may cause stenosis.

STUDY DESIGN

Observational study.

SETTING & PARTICIPANTS

Patients with chronic kidney disease (N = 50) undergoing AVF placement.

PREDICTORS

Medial fibrosis, microcalcification, and intimal hyperplasia in arteries and veins obtained during AVF creation.

OUTCOME & MEASUREMENTS

AVF nonmaturation.

RESULTS

AVF nonmaturation occurred in 38% of patients despite attempted salvage procedures. Preoperative arterial diameter was associated with upper-arm AVF maturation (P = 0.007). Medial fibrosis was similar in patients with nonmaturing and mature AVFs (60% ± 14% vs 66% ± 13%; P = 0.2). AVF nonmaturation was not associated with patient age or diabetes, although both variables were associated significantly with severe medial fibrosis. Conversely, AVF nonmaturation was higher in women than men despite similar medial fibrosis in both sexes. Arterial microcalcification (assessed semiquantitatively) tended to be associated with AVF nonmaturation (1.3 ± 0.8 vs 0.9 ± 0.8; P = 0.08). None of the arteries or veins obtained at AVF creation had intimal hyperplasia. However, repeated venous samples obtained in 6 patients during surgical revision of an immature AVF showed venous neointimal hyperplasia.

LIMITATIONS

Single-center study.

CONCLUSION

Medial fibrosis and microcalcification are frequent in arteries used to create AVFs, but do not explain AVF nonmaturation. Unlike previous studies, intimal hyperplasia was not present at baseline, but developed de novo in nonmaturing AVFs.

Secondary listing for deceased-donor kidney transplantation does not increase likelihood of engraftment at a large transplant center

The supply of donor organs has not increased as fast as has the number of patients awaiting kidney transplantation. Few organs are shared outside the areas of recovery. This trend has caused some ESRD patients to seek listing at multiple centers. We examined UNOS registry data and transplant registry data at the University of Alabama at Birmingham (UAB) for the 576 patients listed at multiple centers over an 8-year span ending December 31, 2005. We identified 72 multilisted patients who received a deceased-donor renal allograft at UAB and reviewed their records for demographics, HLA matching and transfer of listing time. The only predictors for transplantation at UAB were initial listing at UAB or transfer of waiting time. Fifty-one of the 72 patients had listed at UAB first; the other 21 had transferred waiting time. None of the 176 patients who listed elsewhere first and did not transfer waiting time had been transplanted at UAB. Aggregate cost of listing and evaluation for the 176 patients listed elsewhere first who did not transfer waiting time was $1 254 528. Secondary listing at UAB, with a large cohort awaiting transplantation, without transfer of waiting time from another center was an expensive and futile process.

Systolic dysfunction portends increased mortality among those waiting for renal transplant

Individuals waiting for a renal transplant experience excessive cardiovascular mortality, which is not fully explained by the prevalence of ischemic heart disease in this population. Overt heart failure is known to increase the mortality of patients with ESRD, but the impact of lesser degrees of ventricular systolic dysfunction is unknown. For examination of the association between left ventricular ejection fraction(LVEF) and mortality of renal transplant candidates, the records of 2718 patients evaluated for transplantation at one institution were reviewed. During 6355 patient-years (median 27 mo) of follow-up, 681 deaths occurred. Patients with systolic dysfunction (LVEF <or= 0.40) had significantly lower survival than those with higher systolic function (median 49 +/- 3.1 versus 72 +/- 4.0 mo; P 0.001) but had similar survival to patients with ischemia (48 +/- 2.5 mo). Multivariate modeling showed that those with systolic dysfunction were nearly twice as likely to die as those with normal systolic function, adjusted for risk factors including diabetes, left ventricular hypertrophy, and ischemia (adjusted hazard ratio 1.7; 95%confidence interval 1.43 to 2.07). In addition, a graded, reverse association between LVEF and mortality was identified. In conclusion, systolic dysfunction is strongly associated with mortality, in a graded manner, in renal transplant candidates.

Racial Disparities in Renal Allograft Survival: A Public Health Issue?

BACKGROUND

Racial disparities in renal transplantation outcomes have been documented with inferior allograft survival among African Americans compared with non-African Americans. These differences have been attributed to a variety of factors, including immunologic hyperresponsiveness, socioeconomic status, compliance, HLA matching, and access to care. The purpose of this study was to examine both immunologic and nonimmunologic risk factors for allograft loss with a goal of defining targeted strategies to improve outcomes among African Americans.

STUDY DESIGN

We retrospectively analyzed all primary deceased-donor adult renal transplants (n = 2,453) at our center between May 1987 and December 2004. Analysis included the impact of recipient and donor characteristics, HLA typing, and immunosuppressive regimen on graft outcomes. Data were analyzed using standard Kaplan-Meier actuarial techniques and were explored with nonparametric and parametric methods. Multivariable analyses in the hazard-function domain were done to identify specific risk factors associated with graft loss.

RESULTS

The 1-year allograft survival in recipients improved substantially throughout the study period, and 3-year allograft survival also improved. Risk factor analyses are shown by type of allograft and according to specific time periods. Risk of immunologic graft loss (acute rejection) was most prominent during the early phase. During late-phase, immunologic risk persists (chronic rejection), but recurrent disease, graft quality, and recipient's comorbidities have an increasingly greater role.

CONCLUSIONS

Advances in immunosuppression regimens have contributed to allograft survival in both early and late (constant) phases throughout all eras, but improvement in longterm outcomes for African Americans continues to lag behind non-African Americans. The disparity in renal allograft loss between African Americans and non-African Americans over time indicates that beyond immunologic risk, the impact of nonimmunologic variables, such as time on dialysis pretransplantation, diabetes, and access to medical care, can be key issues.

"High-risk" renal transplantation: evolving definitions at a single center

Characterization of renal transplant recipients as "high-risk" originated in the 1970's, although attributes that defined this category, such as diabetes mellitus, are no longer applicable. The changing paradigm of risk after renal transplantation reflects the impact of nonspecific advances in clinical care, specific interventions that address previously defined problems, changing demographics, and new issues that have arisen as a consequence of changes in clinical practice. In the current era, diabetes, retransplantation, and presensitization are no longer considered risk factors for poor outcomes after kidney transplantation. Significant risk factors influencing intermediate-term graft survival now include donor and recipient age over 60 years, DR mismatching (only in kidneys from deceased donors), time awaiting transplantation, and African-American race. Current clinical approaches to care of the renal transplant candidate/recipient focus on minimizing the impact of identified risk factors rather than avoiding transplantation altogether. For most ESRD patients, the greatest risk lies in not receiving a transplant.

Prognostic value of myocardial perfusion imaging in predicting outcome after renal transplantation

Cardiovascular disease is a significant cause of morbidity and mortality after renal transplantation. Pretransplant screening in a subset of these patients for occult coronary artery disease (CAD) may improve outcome. The objective of this study was to examine the outcome of 600 patients after renal transplantation for end-stage renal disease. Prospective outcome data were collected on 600 consecutive patients who had renal transplantation between 1996 and 1998 at our institution at 42 +/- 12 months after surgery. Stress single-photon emission computed tomographic (SPECT) myocardial perfusion imaging was performed in 174 patients before surgery, 136 (78%) of whom had diabetes mellitus. There were a total of 59 events: 17 cardiac deaths, 14 nonfatal myocardial infarctions, and 28 noncardiac deaths. There were 12 cardiac events and 11 noncardiac deaths among those who had SPECT myocardial perfusion imaging. In a multivariate analysis that included important risk factors, age (p = 0.03 and 0.003, respectively) and diabetes (p = 0.02 and 0.005, respectively) were the predictors of total events and cardiac events in patients who did not undergo stress SPECT perfusion imaging. In the subgroup who had stress perfusion imaging, an abnormal perfusion SPECT study was the only predictor of cardiac events (p = 0.006). The 42-month cardiac event-free survival rate was 97% in patients with normal SPECT images and 85% in patients with abnormal SPECT images (RR 5.04, 95% confidence interval 1.4 to 17.6, p = 0.006). Thus, there is a 2.8% event rate per year after renal transplantation, and approximately 50% of these events are noncardiac. In high-risk patients (most of whom had diabetes) with preoperative stress perfusion imaging, those with normal images had significantly lower cardiac events than those with abnormal images. These results have important implications in patient screening and postoperative management.

The report of a national conference on the wait list for kidney transplantation

In March, 2002, over 100 members of the transplant community assembled in Philadelphia for a meeting designed to address problems associated with the growing number of patients seeking kidney transplantation and added to the waiting list each year. The meeting included representatives of nine US organizations with interests in these issues. Participants divided into work groups addressing access to the waiting list, assigning priority on the list, list management, and identifying appropriate candidates for expanded criteria donor kidneys. Each work group outlined problems and potential remedies within each area. This report summarized the issues and recommendations regarding the waiting list for kidney transplantation addressed in the Philadelphia meeting.

Hemodialysis arteriovenous fistula maturity: US evaluation

PURPOSE

To compare various objective ultrasonographic (US) criteria for native arteriovenous fistula (AVF) maturation with subsequent fistula outcomes and clinical evaluation by experienced dialysis nurses.

MATERIALS AND METHODS

US fistula evaluation results were analyzed retrospectively in 69 patients within 4 months after AVF placement; adequacy for dialysis was known in 54. Measurements included minimum venous diameter and blood flow rate. Experienced dialysis nurses examined 30 fistulas clinically. Predictors of fistula adequacy were analyzed with univariate and multivariate logistic regression. Mean fistula diameters and blood flow rates were compared by using analysis of variance or unpaired Student t tests.

RESULTS

Fistula adequacy for dialysis doubled if the minimum venous diameter was 0.4 cm or greater (89% [24 of 27]) versus less than 0.4 cm (44% [12 of 27]; P <.001). Fistula adequacy for dialysis was nearly doubled if flow volume was 500 mL/min or greater (84% [26 of 31]) versus less than 500 mL/min (43% [nine of 21]; P =.002). Combining venous diameter and flow volume increased fistula adequacy predictive value: minimum venous diameter of 0.4 cm or greater and flow volume of 500 mL/min or greater (95% [19 of 20]) versus neither criterion met (33% [five of 15]; P =.002). Women were less likely to have an adequate fistula diameter of 0.4 cm or greater: 40% (12 of 30) of women versus 69% (27 of 39; P =.015) of men. No significant differences in blood flow or minimum venous diameter were found during 2-4 postoperative months. Experienced dialysis nurses' accuracy in predicting eventual fistula maturity was 80% (24 of 30).

CONCLUSION

US measurements of AVF at 2-4 months in patients undergoing hemodialysis are highly predictive of fistula maturation and adequacy for dialysis.

The number of amino acid residues mismatches correlates with flow cytometry crossmatching results in high PRA renal patients

Highly sensitized renal transplant candidates present a group at high risk for acute and chronic rejection. The probability of finding compatible donors for these recipients is significantly lower in comparison to those who have low PRA values. As a consequence, these patients spend longer time on the waiting list and become tethered to dialysis. The results of final cross match (XM) are critical for making a decision about whether such a candidate receives an organ or not. The degree of donor and recipient HLA compatibility predicts the results of XM. The goal of this study was to expand a variety of acceptable HLA-AB mismatches (MM) for high PRA kidney recipients using the HLAMATCHMAKER algorithm. This strategy focuses on the fine structural features of HLA polymorphism comprising amino acid residues or triplets (AAT), which are located in alpha-helical coils of HLA molecules and are available to antibodies. We analyzed serum samples from thirty-nine highly alloimmunized recipients (PRA > or = 85%). The level of sensitization was detected using FlowPRA Class I Screening Test. This group of transplant candidates included thirteen recipients who demonstrated negative results of final T/B FCXM and twenty-six, who were FCXM positive. The application of the HLAMATCHMAKER algorithm based on the HLA class I donor and recipient typing allowed us to detect the total number of AATMM as well as the number of immunogenic AAT in both FCXM negative and FCXM positive groups of recipients. Significantly greater numbers of both total and highly immunogenic AATMM have been emerged in the group of FCXM positive patients. Furthermore, the results of this analysis have shown a high degree of probability of positive FCXM if the number of highly immunogenic AATMM was > or = 1 (chi(2) = 22.9 Yate's correction; p = 0.000001). We did not observe overlapping between antibody specificity and permissible HLA-AB MM detected using the HLAMATCHMAKER strategy. Thus, the number of highly immunogenic AATMM can serve as a reliable predictive value for final FCXM results in highly sensitized renal transplant candidates. The HLAMATCHMAKER algorithm appears to be the proper strategy to find donors for high PRA recipients.

Effect of preoperative sonographic mapping on vascular access outcomes in hemodialysis patients

BACKGROUND

Current DOQI guidelines encourage placing arteriovenous (AV) fistulas in more hemodialysis patients. However, many new fistulas fail to mature sufficiently to be usable for hemodialysis. Preoperative vascular mapping to identify suitable vessels may improve vascular access outcomes. The present study prospectively evaluated the effect of routine preoperative vascular mapping on the type of vascular accesses placed and their outcomes.

METHODS

During a 17-month period, preoperative sonographic evaluation of the upper extremity arteries and veins was obtained routinely. The surgeons used the information obtained to plan the vascular access procedure. The types of access placed, their initial adequacy for dialysis, and their long-term outcomes were compared to institutional historical controls placed on the basis of physical examination alone.

RESULTS

The proportion of fistulas placed increased from 34% during the historical control period to 64% with preoperative vascular mapping (P < 0.001). When all fistulas were assessed, the initial adequacy rate for dialysis increased mildly from 46 to 54% (P = 0.34). For the subset of forearm fistulas, the initial adequacy increased substantially from 34 to 54% (P = 0.06); the greatest improvement occurred among women (from 7 to 36%, P = 0.06) and diabetic patients (from 21 to 50%, P = 0.055). In contrast, the initial adequacy rate of upper arm fistulas was not improved by preoperative vascular mapping (59 vs. 56%, P = 0.75). Primary access failure was higher for fistulas than grafts (46.4 vs. 20.6%, P = 0.001), but the subsequent long-term failure rate was higher for grafts than fistulas (P < 0.05). Moreover, grafts required a threefold higher intervention rate (1.67 vs. 0.57 per year, P < 0.001) to maintain their patency. The overall effect of this strategy was to double the proportion of patients dialyzing with a fistula in our population from 16 to 34% (P < 0.001).

CONCLUSIONS

Routine preoperative vascular mapping results in a marked increase in placement of AV fistulas, as well as an improvement in the adequacy of forearm fistulas for dialysis. This approach resulted in a substantial increase in the proportion of patients dialyzing with a fistula in our patient population. Fistulas have a higher primary failure rate than grafts, but have a lower subsequent failure rate and require fewer procedures to maintain their long-term patency.

Tolerance in renal transplantation after allogeneic bone marrow transplantation-6-year follow-up

Despite significant advancements in clinical transplantation, very few reports describe the long-term acceptance of transplanted solid organs without indefinite immunosuppression. The immunosuppressive agents used are nonspecific and have serious potential side effects. We present a patient who received a living-donor renal allograft from the same person who had donated bone marrow to her several years earlier. Tolerance was expected based on previous acceptance of full-thickness skin grafts from the donor. Indeed, there has been no evidence of rejection during a 6-year follow-up period, and no induction or maintenance immunosuppression has been given. All noninvasive parameters of graft function remain normal. This and similar reports prove that genetically disparate solid organs can coexist without pharmacological immunosuppression.

Risk and benefit of coronary revascularization in renal transplant candidates

The field of transplantation along with all of medicine has made tremendous progress in the past 30 years. Patients with end-stage renal disease are managed more effectively despite increasing chronic multisystemic comorbidities, particularly involving their cardiovascular system. These same patients are also undergoing renal transplant surgery with better short- and long-term results than any era previous. We will present some of the changing demographics encountered in today's renal transplant candidates along with the processes our institution is undertaking to optimize the patient's success with the renal allograft, particularly with respect to the diagnosis and therapeutics used to manage coronary artery disease.

Specificity of preformed alloantibodies causing B cell positive flow crossmatch in renal transplantation

The specificity of alloantibodies (alloAb) and their clinical significance in association with T-/B+ flow cytometry crossmatch (FCXM) in kidney transplantation are not clearly defined. This study was undertaken to examine the HLA specificity and clinical relevance of Ab causing B+ FCXM in pre-transplant (final XM) recipients' serum samples. Final FCXM serum samples were analyzed from 457 renal transplant patients followed for 10 months post-transplantation. Two hundred and sixty patients had T-/B+ final FCXM. The control group included 197 recipients with T-/B- FCXM at time of transplantation. Class I/class II PRA and specificity of anti-HLA class I and class II Ab in final FCXM serum samples were analyzed by FlowPRA Class I Screening Test and FlowPRA Class II Screening Test. We found no correlation between graft outcome and pre-transplant T-/B- and T-/B+ FCXM status. Additionally, we observed no clinical relevance of B+ FCXM in retransplant patients. However, MCS > or =200 in B+ FCXM retransplant recipients was associated with anti-class II Ab to previous mismatches in regrafted patients (n = 46). This finding was confirmed by specificity analysis of anti-DR/DQ Ab in patients with high ( > or =15%) class II PRA. In 63% (12 of 19) of retransplants having T-/B+ FCXM, we defined the specificity of alloAb to first graft mismatched class II antigens. In contrast, anti-class II Ab was detected in only 5.7% (2 of 35) of single-graft recipients with different PRA values. Significantly greater MCS (240 +/- 61 vs. 163 +/- 48; p = 0.022) was observed in retransplant patients having short ( < or =5 m) previous graft survival time (PGST) than in those with long PGST ( > or =5 m). Only 2% of retransplant recipients with B + FCXM had non-HLA Ab. In contrast, the overwhelming majority of primary recipients had no detectable alloAbs. No significant difference in class I PRA was found between B- and B+ FCXM recipients. However, class II PRA was significantly higher in patients having B + FCXM (p = 0.028). Collectively, these data show that MCS intensity is not always a reliable criterion for anti-HLA Ab detection because of the presence of non-HLA Ab. These results can be explained by low titers of anti-class II Ab, at which concentration these Ab cannot produce a deleterious effect. FlowPRA and Flow screen beads appeared to be reliable and sensitive methods for detection and specificity analysis of anti-class II alloAb.

Improved outcomes in cadaveric renal allografts with pulsatile preservation

BACKGROUND

Early immunologic and non-immunologic injury of renal allografts adversely affects long-term graft survival. Some degree of preservation injury is inevitable in cadaveric renal transplantation, and, with the reduction in early acute rejection, this non-immunologic injury has assumed a greater relative importance. Optimal graft preservation will maximize the chances of early graft function and long-term graft survival, but the best method of preservation pulsatile perfusion (PP) versus cold storage (CS) is debated.

METHODS

Primary cadaveric kidney recipients from January 1990 through December 1995 were evaluated. The effects of implantation warm ischemic time (WIT) ( < or = 20 min, 21-40 min, or > 40 min) and total ischemic time (TIT) ( < or > or = 20 h) on death-censored graft survival were compared between kidneys preserved by PP versus those preserved by CS. The effect of preservation method on delayed graft function (DGF) was also examined.

RESULTS

There were 568 PP kidneys and 268 CS kidneys. Overall death-censored graft survival was not significantly different between groups, despite worse donor and recipient characteristics in the PP group. CS kidneys with an implantation WIT > 40 min had worse graft survival than those with < 40 min (p = 0.0004). Survival of PP kidneys and those transplanted into 2 DR-matched recipients was not affected by longer implantation WIT. Longer TIT did not impact survival. DGF was more likely after CS preservation (20.2% versus 8.8%, p = 0.001).

CONCLUSIONS

Preservation with PP improves early graft function and lessens the adverse effect of increased warm ischemia in cadaveric renal transplantation. This method is likely associated with less preservation injury and/or increases the threshold for injury from other sources and is superior to CS.

Review of select transplant subpopulations at high risk of failure from standard immunosuppressive therapy

Despite improvements in short-term graft and patient survival rates for solid organ transplants, certain subgroups of transplant recipients experience poorer clinical outcome compared to the general population. Groups including pediatrics, African-Americans, diabetics, cystic fibrosis patients, and pregnant women require special considerations when designing immunosuppressive regimens that optimize transplant outcomes. Problems specific to pediatric transplant recipients include altered pharmacokinetics of immunosuppressive drugs, such as cyclosporine (CsA) and tacrolimus (poor absorption, increased metabolism, rapid clearance), the need to restore growth post-transplantation, and a high incidence of drug-related adverse effects. African-Americans have decreased drug absorption and bioavailability, high immunologic responsiveness, and a high incidence of post-transplant diabetes mellitus. Diabetics and cystic fibrosis patients exhibit poor absorption of immunosuppressive agents, which may lead to underimmunosuppression and subsequent graft rejection. Pregnant women undergo physiologic changes that can alter the pharmacokinetics of immunosuppressives, thus requiring careful clinical management to minimize the risks of either under- or overimmunosuppression to mother and child. To achieve an optimal post-transplant outcome in these high-risk patients, the problems specific to each group must be addressed, and immunosuppressive therapy individualized accordingly. Drug formulation greatly impacts upon pharmacokinetics and the resultant level of immunosuppression. Thus, a formulation with improved absorption (e.g., CsA for microemulsion), higher bioavailability, and less pharmacokinetic variability may facilitate patient management and lead to more favorable outcomes, especially in groups demonstrating low and variable bioavailability. Other strategies aimed at improving transplant outcome include the use of higher immunosuppressive doses, different combinations of immunosuppressive agents, more frequent monitoring, and management of concurrent disease states.

US vascular mapping before hemodialysis access placement

PURPOSE

To prospectively assess the effect of preoperative ultrasonographic (US) mapping on surgical selection, placement of arteriovenous fistulas (AVFs) and grafts, and negative surgical exploration rates.

MATERIALS AND METHODS

US assessment of the upper extremity arterial and venous anatomy was performed in 70 patients with chronic renal failure before surgical evaluation. The surgeon documented the planned access procedure, which was based on physical examination results, and then reviewed the US preoperative mapping report. The surgical procedure and outcome were recorded.

RESULTS

Fifty-two of the 70 patients who underwent mapping had vascular access placement. Preoperative US mapping resulted in a change in the planned surgical procedure in 16 (31%) of the 52 patients. An AVF rather than the planned graft was placed in eight (15%) patients. The AVF placement rate increased from 32% (126 of 395 patients) to 58% (30 of 52 patients). Unsuccessful surgical explorations decreased from 11% (28 of 256) to 0%.

CONCLUSION

Preoperative US mapping before hemodialysis access placement can result in a change in surgical management, with an increased number of AVFs placed and an improved likelihood of selecting the most functional vessels preoperatively. Further study is needed to determine longer term outcomes.

Natural history of arteriovenous grafts in hemodialysis patients

Most hemodialysis patients in the United States have an arteriovenous graft as their vascular access. Grafts have a relatively short life span and are prone to recurrent stenosis and thrombosis, requiring multiple salvage procedures to maintain their patency. There is little information in the literature regarding the clinical factors that determine graft survival and complications. We evaluated prospectively the outcomes of 256 grafts placed at a single institution during a 2-year period. A salvage procedure to maintain graft patency (thrombectomy, angioplasty, or surgical revision) was required in 29% of the grafts at 3 months, 52% at 6 months, 77% at 12 months, and 96% at 24 months. Thus, primary graft survival (time from graft placement to the first intervention) was only 23% at 1 year and 4% at 2 years. Primary graft survival was significantly less among patients with hypoalbuminemia compared with patients with a normal serum albumin level (P = 0.003). Secondary graft survival (time from graft placement to permanent graft failure) was 65% at 1 year and 51% at 2 years. Neither primary nor secondary graft survival was significantly correlated with patient age, sex, diabetic status, body mass index, or graft site. A mean of 1.22 interventions per graft-year were required to maintain access patency, including 0.51 thrombectomies, 0.54 angioplasties, and 0.17 surgical revisions. In conclusion, hypoalbuminemia is a strong predictor of the requirement for an early graft intervention. Patients with hypoalbuminemia may require a heightened index of suspicion in monitoring their grafts for evidence of stenosis.

Postransplant lymphoproliferative disorder localized near the allograft in renal transplantation

BACKGROUND

Posttransplant lymphoproliferative disorder (PTLD), a complication of immunosuppression, develops in approximately 1% of renal allograft recipients. Typically, PTLD is a proliferation of B-cells associated with Epstein-Barr virus (EBV) infection; it is said to be most often a systemic disease. Involvement occasionally is localized near the allograft.

METHODS

This is a retrospective analysis of all cases of PTLD in recipients of 1474 renal transplants performed at University of Alabama at Birmingham between 1993 and 1997.

RESULTS

Of 14 patients developing PTLD, 10 had disease localized near the allograft. The mean interval from transplantation to diagnosis was 221 +/- 70 days. All patients presented with renal dysfunction; an ultrasound examination revealed a hilar mass, with hydronephrosis in five and stenosis of renal vessels in eight. No patient had lymphadenopathy, according to computerized tomographic or magnetic resonance imaging findings. After reduction of immunosuppressive therapy, seven required a nephrectomy because of rejection, progressive dysfunction, or mass enlargement. Tissue recovered in four patients was consistent with PTLD; the tumors in the remaining three patients were unresectable and regressed. One patient died 1 month after a nephrectomy, and another died 4 years after surgery; neither had evidence of PTLD when they died. Three patients retain functional grafts without clinical or radiographical evidence of progression. All patients with disseminated disease died.

CONCLUSIONS

In a large cohort of renal allograft recipients, PTLD affected 1%. Disease localized near the allograft was the most common variant. For most patients with localized disease, the outcome was graft loss, and the mortality was low. Localized PTLD should be considered in the differential diagnosis of allograft dysfunction in the 1st posttransplant year.

Renal retransplantation at the University of Alabama at Birmingham: incidence and outcome

Only half the patients who lost a renal allograft either returned to the waiting list (32%) or were retransplanted (17%). One fifth died soon after allograft loss. Patients did not return to the waiting list for multiple reasons including patient choice, worsened medical condition and most commonly, interest but non-referral. Diabetics had a significantly diminished chance for survival on dialysis after graft loss. African-Americans had a better chance of survival after graft loss but a much worse opportunity to be retransplanted. The use of CellCept in triple immunosuppressive therapy, along with a flow cytometry crossmatch, has improved retransplant allograft survival commensurate with primary graft outcome. The incidence of retransplantation is decreasing at our institution even though the number of potential candidates for retransplantation remains stable.

Predictors of adequacy of arteriovenous fistulas in hemodialysis patients

BACKGROUND

Dialysis access procedures and complications represent a major cause of morbidity, hospitalization, and cost for chronic dialysis patients. To improve the outcomes of hemodialysis access procedures, recent clinical guidelines have encouraged attempts to place an arteriovenous (A-V) fistula, rather than an A-V graft, whenever possible in hemodialysis patients. There is little information, however, about the success rate of following such an aggressive strategy in the prevalent dialysis population.

METHODS

We evaluated the adequacy of all A-V fistulas placed in University of Alabama at Birmingham dialysis patients during a two-year period. A fistula was considered adequate if it supported a blood flow of >/=350 ml/min on at least six dialysis sessions in one month. Fistula adequacy was correlated with clinical and demographic factors.

RESULTS

The adequacy could be determined for 101 fistulas; only 47 fistulas (46.5%) developed sufficiently to be used for dialysis. The adequacy rate was lower in older (age >/= 65) versus younger (age < 65) patients (30.0 vs. 53.5%, P = 0.03). It was also marginally lower in diabetics versus nondiabetics (35.0 vs. 54.1%, P = 0.061) and in overweight (BMI >/= 27 kg/m2) versus nonoverweight patients (34.5 vs. 55.2%, P = 0.07). The adequacy rate was not affected by patient race, smoking status, surgeon, serum albumin, or serum parathyroid hormone. The adequacy rate was substantially lower for forearm versus upper arm fistulas (34.0 vs. 58.9%, P = 0.012). The adequacy of forearm fistulas was particularly poor in women (7%), patients age 65 or older (12%), and diabetics (21%). In contrast, upper arm fistulas were adequate in 56% of women, 54% of older patients, and 48% of diabetics.

CONCLUSIONS

An aggressive approach to the placement of fistulas in dialysis patients results in a less than 50% early adequacy rate, which is considerably lower than that reported in the past. Moreover, the success rate of fistulas is even lower for certain patient subsets. To achieve an optimal outcome with A-V fistulas, we recommend that they be constructed preferentially in the upper arm in female, diabetic, and older hemodialysis patients.

A multidisciplinary approach to hemodialysis access: prospective evaluation

Dialysis access procedures and complications represent a major cause of morbidity, hospitalization and cost for chronic dialysis patients. To improve outcomes and reduce the cost of hemodialysis access procedures we developed a multidisciplinary approach, involving nephrologists, access surgeons, and radiologists. A full-time dialysis access coordinator scheduled all access procedures with the surgeons and radiologists, and tracked outcomes. A computerized database was developed for prospective documentation of procedures and complications. Confidential, detailed analyses and recommendations for improvements were provided periodically to the surgeons and radiologists. The major changes arising from the multidisciplinary approach were as follows: (1) The approach to clotted grafts evolved from an inpatient surgical procedure to an outpatient radiologic procedure. The immediate technical success rate of graft declots increased from 48% to 69%. (2) Elective placement of arteriovenous (A-V) grafts evolved from a three-day inpatient hospitalization to a largely outpatient procedure. The proportion of A-V grafts placed as same day surgery or outpatient surgery increased from 16% to 81%. (3) Surgical complications of new A-V graft surgery decreased from 25% to 11%. (4) Aggressive detection and correction of graft stenosis decreased the incidence of graft thrombosis by 60%, from 0.70 to 0.28 events per patient-year. (5) The proportion of native A-V fistula construction in new dialysis patients increased from 33% to 69%. In conclusion, an integrated multidisciplinary approach markedly reduced surgical complications of access surgery and decreased access failures. These improvements occurred despite a marked decrease in hospitalization for access procedures, with a substantial cost saving.

A comparison of tacrolimus (FK506) and cyclosporine for immunosuppression after cadaveric renal transplantation. FK506 Kidney Transplant Study Group

BACKGROUND

Tacrolimus (FK506), a macrolide molecule that potently inhibits the expression of interleukin 2 by T lymphocytes, represents a potential major advance in the management of rejection following solid-organ transplantation. This randomized, open-label study compared the efficacy and safety of tacrolimus-based versus cyclosporine-based immunosuppression in patients receiving cadaveric kidney transplants.

METHODS

A total of 412 patients were randomized to tacrolimus (n=205) or cyclosporine (n=207) after cadaveric renal transplantation and were followed for 1 year for patient and graft survival and the incidence of acute rejection.

RESULTS

One-year patient survival rates were 95.6% for tacrolimus and 96.6% for cyclosporine (P=0.576). Corresponding 1-year graft survival rates were 91.2% and 87.9% (P=0.289). There was a significant reduction in the incidence of biopsy-confirmed acute rejection in the tacrolimus group (30.7%) compared with the cyclosporine group (46.4%, P=0.001), which was confirmed by blinded review, and in the use of antilymphocyte therapy for rejection (10.7% and 25.1%, respectively; P<0.001). Impaired renal function, gastrointestinal disorders, and neurological complications were commonly reported in both treatment groups, but tremor and paresthesia were more frequent in the tacrolimus group. The incidence of posttransplant diabetes mellitus was 19.9% in the tacrolimus group and 4.0% in the cyclosporine group (P<0.001), and was reversible in some patients.

CONCLUSIONS

Tacrolimus is more effective than cyclosporine in preventing acute rejection in cadaveric renal allograft recipients, and significantly reduces the use of antilymphocyte antibody preparations. Tacrolimus was associated with a higher incidence of neurologic events, which were rarely treatment limiting, and with posttransplant diabetes mellitus, which was reversible in some patients.

Benefits of continued cyclosporine through an indigent drug program

Financial circumstances force some stable renal transplant recipients to discontinue cyclosporine (CsA). Previous results from our center document a subgroup of these patients at increased risk for acute rejection and allograft loss, namely, those of African ancestry. After 1988, such disadvantaged recipients have been able to receive CsA at no charge through the National Organization for Rare Disorders (NORD). At the University of Alabama at Birmingham, 54 patients were enrolled in the NORD program between 1988 and 1994. Acute rejection, allograft survival, and patient survival in these patients were compared with those in 42 patients who, prior to 1988, were withdrawn from CsA for financial reasons. Both groups were similar socioeconomically. The mean follow-up was 69 +/- 33 months (+/-SD) in the withdrawal group and 45 +/- 14 months in those entering the NORD program. Acute rejections occurred with similar frequency in both groups before CsA withdrawal (45%) or NORD enrollment (48%). In contrast, acute rejections were more common in patients after the onset of CsA withdrawal (38%) than after NORD enrollment (11%) (P < 0.01). Black patients withdrawn from CsA experienced more acute rejections than their counterparts in the NORD program (57% v 15%) (P < 0.01). White NORD recipients also experienced fewer acute rejections, although the difference was not statistically significant (withdrawal group 16% v NORD group 4%; P = 0.29). Rejection episodes were accompanied by reduced graft survival in black patients withdrawn from CsA, while significant improvement was seen in those remaining on CsA-based therapy (P < 0.05). No difference in allograft survival was seen among white patients in either group (withdrawal group 74% v NORD group 82%; P = 0.33). Thus, long-term access to CsA through the NORD program reduced acute rejections and improved allograft survival in an economically disadvantaged subgroup of renal transplant recipients. These findings emphasize the importance of continued access to CsA in black renal transplant recipients and its influence on long-term allograft survival.

A multicenter trial of FK506 (tacrolimus) therapy in refractory acute renal allograft rejection. A report of the Tacrolimus Kidney Transplantation Rescue Study Group

A multicenter trial was conducted to evaluate the efficacy and safety of tacrolimus in the treatment of refractory renal allograft rejection. Renal transplant recipients experiencing biopsy-proven recurrent acute allograft rejection were eligible if the current rejection episode was refractory to corticosteroids. A total of 73 patients were enrolled, of whom 59 (81%) had previously received at least one course of antilymphocyte antibody as rejection therapy. One-year follow-up was available in 93% of patients. Median time to tacrolimus rescue therapy was 75 days after transplantation (range, 18-1448 days). Therapeutic responses to tacrolimus included improvement in 78% of patients, stabilization in 11%, and progressive deterioration in 11%. The risk of experiencing progressive deterioration was related to the pretacrolimus serum creatinine level: serum creatinine < or = mg/dl, 3%; 3.1-5 mg/dl, 16% (P < 0.04); > 5 mg/dl, 23% (P < 0.02). Twelve-month (from the time of initiation of tacrolimus therapy) actuarial patient and graft survival rates were 93% and 75%. Graft loss occurred in 19 patients (25%) at a median time of 108 days. Fourteen episodes of recurrent rejection were diagnosed in 10 patients (14%), at a median time of 101 days. Eleven episodes of recurrent rejection were treated (three patients underwent transplant nephrectomy), with resolution achieved in nine patients. Antilymphocyte antibody therapy was not used to treat recurrent rejection. Serum creatinine values improved during tacrolimus therapy: median serum creatinine level before tacrolimus, 3.2 mg/dl; median at 1 year after tacrolimus, 1.8 mg/dl. Twelve infections were documented in 11 patients (15%), including cytomegalovirus infection in three patients (4%). Posttransplant lymphoproliferative disorder was diagnosed in a single patient. Tacrolimus whole blood levels averaged 15.0 +/- 9.9 ng/ml at day 7 of tacrolimus therapy and 9.4 +/- 5.1 ng/ml at 1 year, and were consistent among individual centers. Treatment outcome did not correlate with tacrolimus blood levels. The most commonly observed adverse events were neurological and gastrointestinal. Seventy-four percent of patients received tacrolimus for at least 1 year. Tacrolimus therapy was discontinued in 18% of patients for rejection (11% for progressive, unrelenting rejection, and 7% for recurrent rejection). Tacrolimus therapy was discontinued in 8% of patients due to adverse events. In conclusion, tacrolimus rescue therapy provides (1) prompt, effective reversal of refractory renal allograft rejection, (2) good long-term renal allograft function, (3) a low incidence of recurrent rejection, and (4) an acceptable safety profile in renal allograft recipients experiencing refractory rejection.

Impact of donor/recipient size matching on outcomes in renal transplantation

Interest in nonimmunologic factors affecting longterm graft survival has focused on adequacy of nephron dosing. Body surface are (BSA) is a reliable surrogate for nephron mass. In a retrospective study of 378 primary recipients of paired kidneys from 189 cadaveric donors, we assessed the impact of matching donor and recipient BSA on outcome over 7 years. BSA of donors was 1.82 +/- 0.26 m2. Initially, paired recipients of kidneys from a single donor were divided into two groups. Group 1 included the recipient with the larger BSA of the pair (1.97 +/- 0.17 m2), while group 2 consisted of smaller BSA recipients (1.69 +/- 0.19 m2). Although early function was better in group 2 patients, graft survival at 1 year (77% vs. 79%) and 5 years (54% vs. 55%) was identical between groups, as were most recent serum creatinine levels (2.0 +/- 0.1 vs. 2.1 +/- 0.1 mg/dl). A second analysis divided patients with a functioning allograft at discharge from initial transplant hospitalization (n = 345) into three groups based solely on donor to recipient BSA ratio: the ratio of group A (n = 30) was < or = 0.8, that of group B (n = 255) was between 0.81 and 1.19, and that of group C (n = 51) was > or = 1.2. Graft survival and kidney function over 5 years did not differ among groups. In multivariate analysis of 17 variables, donor:recipient BSA, independent of other risk factors, did not affect risk allograft loss. These data indicate that including nephron mass as a criterion for cadaveric organ allocation is unlikely to improve long-term results in renal transplantation.

Risk factors affecting second renal transplant outcome, with special reference to primary allograft nephrectomy

Removal of a failed primary renal allograft was found by some groups to adversely affect the outcome of a second kidney transplant. Recent data does not support this view and fail to show any such effect. Such data, however, are limited by small numbers or univariate analysis. The records of 192 patients receiving a primary and a subsequent kidney transplant between January 1980 and July 1992 were retrospectively reviewed. Immunosuppression initially included azathioprine and prednisone; cyclosporine was introduced in December 1983 with Minnesota antilymphocyte globulin (MALG) added for induction in May 1987. Regraft survival rates were 66% at one year and 60% at two years. Using Kaplan-Meier survival analysis patients having primary transplant nephrectomy had a worse second allograft outcome than patients who kept their failed grafts (P = 0.0003). Multivariate analysis showed a significant relationship between primary allograft survival and retransplant outcome. To eliminate this influence, patients whose first graft failed within six months of transplantation were excluded from the analysis. This resulted in 90 patients whose first graft functioned for more than 6 months. Graft survival was 80% at one year and 73% at 2 years in this select population. Patients with prior transplant nephrectomy still had a worse retransplant outcome than those who kept their failed grafts (P = 0.05). Multivariate analysis identified primary allograft nephrectomy, older donor age, longer interval from nephrectomy to retransplant, and lack of MALG at induction as negative risk factors. In conclusion, primary allograft nephrectomy may have a negative influence on second renal transplant outcome. This result may be improved by reducing donor age and the time interval from nephrectomy to retransplantation, and using MALG at induction.

Progress in renal transplantation. A single center study of 3359 patients over 25 years

OBJECTIVE

The study analyzed 3359 consecutive renal transplant operations for patient and graft survival, including living related, cadaveric, and living unrelated patients. The analysis was separated into three groups according to immunosuppression and date of transplant.

SUMMARY BACKGROUND DATA

Improvements in renal transplantation in the past 25 years have been the result of better immunosuppression, organ preservation, and patient selection.

METHODS

A single transplant center's experience over a 25-year period was analyzed regarding patient and graft survival. Potential risk factors included patient demographics, tissue typing, donor characteristics, number of transplants, acute and chronic rejection, acute tubular necrosis, primary disease, and malignancy.

RESULTS

The primary cause of graft loss was rejection. Improvement in cadaveric graft survival since 1987 with quadruple therapy was not apparent in living donor patients. Race continued to be a negative factor in graft survival. Avoiding previous mismatched antigens and the use of flow cytometry improved allograft survival. The leading cause of death in the past 7 years in cadaveric recipients was cardiac (52%).

CONCLUSIONS

Improved graft survival in the past 25 years was related to 1) advances in immunosuppression, 2) better methods of cytotoxic antibody detection, and 3) human lymphocyte antigen match.

A rapid flow cytometry assay for HLA antibody detection using a pooled cell panel covering 14 serological crossreacting groups

Many studies have demonstrated the usefulness of flow cytometry crossmatching (FC-XM) for selection of regraft recipients, and more recently this assay has been shown to correlate with allograft survival in primary cadaveric transplant patients. The need now exists for a practical antibody screening procedure which uses the same methodology. We describe here a simple and sensitive method to screen for HLA antibodies by FC using a pool of 6 cells selected to cover the 14 serological crossreacting groups defined by Rodey. Screenings of 367 sera (255 primary transplant sera, 112 regraft sera) received for monthly antibody testing were performed by both pooled cell FC and complement-dependent cytotoxicity (CDC) assays. Forty of these sera were also FC-screened using a panel of 16 individual cells for comparison with the pooled cell FC screenings. Analysis indicated a strong correlation between the pooled FC-PRA and the individual cell panel FC-PRA (P = .0001) with mean values of 60% and 73%, respectively. Only 2 of the 40 sera screened by both FC methods resulted in PRAs that differed by > 40%. The majority (82%) of the primary patients did not exhibit HLA antibodies by CDC--however, 22% of the CDC negative patients were positive by flow cytometry. Females were more likely to be positive by FC (35%) than males (16%) (P = .0001). Similarly, black patients were more likely to have FC-demonstrable antibodies (28%) than white candidates (14%) (P = .014). The regraft patients who tested positive by either or all methods had a mean PRA for CDC, pooled FC-PRA, and individual cell FC-PRA of 40, 75, and 85, respectively. FC-PRA proved to be a more sensitive technique in both primary and regraft patients.

Treatment of recurrent heart rejection with mycophenolate mofetil (RS-61443): initial clinical experience

Mycophenolate mofetil (RS-61443), a derivative of mycophenolic acid, is a new immunosuppressive agent that inhibits de novo purine synthesis in activated lymphocytes. In a clinical trial of mycophenolate mofetil in the treatment of recurrent or persistent heart rejection, 17 patients 0.6 to 104 months (median 5.4 months) after transplantation received a daily oral dose of mycophenolate mofetil of 3000 mg, with seven patients increasing to 3500 mg daily. Azathioprine was routinely discontinued at the start of mycophenolate mofetil treatment. One patient in shock from acute rejection required retransplantation before starting mycophenolate mofetil and died 68 days later of cytomegalovirus sepsis. Another patient died 72 days after mycophenolate mofetil of protracted multisystem failure (present before mycophenolate mofetil). One patient required early cessation of mycophenolate mofetil, and the other 14 patients were alive and well 5 to 10 months after initiating mycophenolate mofetil treatment. Three patients required transient dose reduction and one patient required discontinuation of mycophenolate mofetil because of nausea, diarrhea, or abdominal cramps. No other clinical side effects were noted. Frequency of rejection decreased from 0.67 rejection episodes per patient per month before mycophenolate mofetil to 0.27 rejection episodes per patient per month after mycophenolate mofetil (p < 0.0001). Frequency of infection was unchanged after mycophenolate mofetil (p = 0.9). Renal function was not affected by mycophenolate mofetil (creatinine clearance 1.8 mg/dl before mycophenolate mofetil vs 1.7 mg/dl after mycophenolate mofetil; p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Renal retransplantation: the role of race, quadruple immunosuppression, and the flow cytometry cross-match

To assess the impact of quadruple immunosuppression in black and white recipients of cadaver kidney retransplants, we reviewed data from 178 second or subsequent renal allografts performed at our center between 1985 and 1991. Sixty-six black and 102 white recipients were divided into 3 groups: groups 1 and 2 consisted of patients with a negative complement-dependent cytotoxicity (CDC) T cell cross-match, receiving triple drug therapy (CsA-AZA-prednisone) and quadruple immunosuppressive therapy (quad therapy; Minnesota antilymphoblast globulin-CsA-AZA-prednisone), respectively. Group 3 patients also received quad therapy, but, in addition to a negative CDC cross-match, had a negative T cell flow cytometry cross-match (FCXM). Black and white patients in groups 1 and 2 experienced similar graft survival at 1 year, ranging from 47% to 63% (P = NS). In group 3, 1-year graft survival in whites, but not blacks, improved to 82%, with fewer grafts lost to immunologic causes in the first 90 days after transplant. A parametric analysis of potential risk factors identified a significant effect of better HLA-DR matching (P = 0.0005) on improved graft survival, with previous mismatched antigens (P = 0.04), female donor (P = 0.002), and short duration of previous graft (P = 0.05) as risk factors for graft loss. Race and immunosuppressive protocol did not affect graft survival. In group 3, blacks received fewer well-matched kidneys than whites (P = 0.05), which may have contributed to poorer outcomes for black recipients. Nine of 10 patients undergoing retransplantation with a negative CDC cross-match and a positive T cell FCXM suffered graft loss at a median of 26 days after transplant. Thus, quad therapy did not enhance graft survival for either black or white patients undergoing cadaveric retransplantation. Immunologic considerations, including HLA-DR matching and the FCXM, continue to exert a strong influence on outcomes in these high-risk recipients.

Experience with mycophenolate mofetil (RS61443) in renal transplantation at a single center

OBJECTIVE

Mycophenolate mofetil (MM) is a new immunosuppressive agent that reversibly inhibits guanine nucleotide synthesis and DNA replication. Its activity is highly selective for T and B lymphocytes. Two open-label multicenter trials of MM in renal transplantation have been performed. This report summarizes the results from one center involved in these two trials.

METHODS AND RESULTS

The initial trial of MM was an open-label dose-ranging trial in primary cadaveric renal transplantation. Mycophenolate mofetil was included in the maintenance immunosuppression regimen from the day after transplantation. Of the 21 patients enrolled in this trial, one (5%) was withdrawn for side effects. There was one graft loss due to recurrent renal disease and two patients were withdrawn for difficulty with follow-up. Mean follow-up is 26 months, and patient and graft survival at 2 years are 100 and 95% respectively. The second trial was designed to study the efficacy of mycophenolate in reversing refractory renal allograft rejection. Patients enrolled in the trial had biopsy-proven acute rejection and had previously received at least one course of high-dose corticosteroids and/or OKT3. Of the 26 patients enrolled in this trial, one (4%) was withdrawn for side effects. There were two deaths. Mean follow-up is 20 months, and patient and graft survival at 12 months was 91 and 54%. The incidence of infections in the two groups was 38% and there were no deaths in either group attributable to infection.

CONCLUSIONS

The results of these two studies indicate that mycophenolate mofetil could be administered safely to renal allograft recipients for periods up to 2 years. It appears to be effective in reversing acute rejection in a high percentage of patients refractory to other forms of therapy.

Tapering or discontinuing cyclosporine for financial reasons--a single-center experience

In patients with primary cadaveric renal transplants and stable allograft function, we assessed the impact of tapering or discontinuing cyclosporine A (CsA) for financial reasons. Forty-two patients whose CsA was discontinued ("no-dose") and 29 patients whose CsA was tapered to 100 to 150 mg/d ("low-dose"; mean, 1.7 mg/kg/d) were examined. Results were compared with 70 age- and race-matched control patients maintained on at least 200 mg/d of CsA (mean, 3.9 mg/kg/d). Follow-up time for all patients averaged 55 +/- 18 months. Late acute rejection episodes occurred more frequently in no-dose than in low-dose (P = 0.017) or control (P = 0.001) patients. In the no-dose group, blacks experienced a greater number of late acute rejections than whites. These late acute rejections often coincided with the discontinuation of CsA and contributed to an increased rate of allograft loss in blacks in the no-dose group compared with black and white controls (P = 0.011). In contrast, no increase in late acute rejection episodes occurred in blacks tapered to low doses of CsA. Black patients who remained on low doses of CsA also exhibited a trend toward allograft survival that was intermediate between that of control and no-dose patients. In those patients who retained functional allografts, mean serum creatinine concentration did not differ between the study groups at the beginning and end of the follow-up period. These findings support continuance of CsA in black primary cadaveric renal transplant patients, even if dosages must be reduced to 100 to 150 mg/d.(ABSTRACT TRUNCATED AT 250 WORDS)

RS-61443 (mycophenolate mofetil). A multicenter study for refractory kidney transplant rejection

RS-61443 (mycophenolate mofetil) inhibits a key enzyme of the de novo synthesis of purine nucleotides in T and B lymphocytes. The purpose of this study was to evaluate the efficacy of RS-61443 in patients with refractory renal allograft rejection. Patients eligible for the study had previously undergone anti-rejection therapy with high-dose steroids or OKT3 monoclonal antibody. All rejection episodes were proven by renal biopsy. Successful rescue was achieved in 52 (69%) patients. Rescue was more successful when patients were entered with a creatinine of 4 mg/dL or lower (79%), versus a 52% rescue rate in patients entered with a creatinine of 4 mg/dL or above. Major side effects were predominantly gastrointestinal, but there was no overt nephrotoxicity, hepatotoxicity, or bone marrow suppression. The overall infection rate was 40%, with the spectrum of infections characteristic for the highly immunocompromised patient. The conclude that this pilot study suggests that RS-61443 is effective in refractory kidney allograft rejection. Based on this study, prospectively randomized multi-center trails have been planned and are in progress.

Benefits of quadruple immunosuppressive therapy in recipients of living related donor kidneys. A review of 855 operations

Eight hundred fifty-five living related donor transplant recipients were analyzed according to 15 potential risk factors with regard to patient and graft survival according to immunosuppression. Group I, 1968 to 1983, (n = 440 patients) received azathioprine and prednisone; group II, 1984 to 1987, (n = 229 patients) received triple therapy--azathioprine, prednisone, and cyclosporine; and group III, 1988-1991, (n = 186 patients), quadruple therapy--azathioprine, prednisone, cyclosporine, and Minnesota antilymphocyte globulin. Three important risk factors included immunosuppression, tissue typing, and race. Groups II and III had improved allograft survival over group I (p = 0.03). Patients with two haplotype matches had similar survival in all three groups. Kidney survival in one-haplotype-matched recipients improved in group II and was equal to that of the two-haplotype-matched patients in group III. Cyclosporine improved allograft survival in both races when combined with azathioprine and prednisone. Quadruple therapy improved early survival in one-haplotype black patients, even though long-term results remained better in whites. Cyclosporine did not improve graft survival in two-haplotype recipients. The addition of cyclosporine and quadruple therapy did not increase morbidity and mortality rates.

The impact of the UNOS mandatory sharing policy on recipients of the black and white races--experience at a single renal transplant center

The impact of the United Network for Organ Sharing mandatory sharing policy on a large transplant center procuring kidneys primarily from caucasians while serving a pool of prospective recipients composed mainly of blacks is described. This policy requires that all 6-antigen-matched and phenotypically identical donor kidneys be shipped to the appropriately matched recipients. The study consisted of 49 kidneys from 25 cadaveric donors; one kidney was unusable. In general, the 33 recipients of the mandatorily shared kidneys were caucasian (94%), unsensitized (70%), and first-time transplants (73%). Allograft survival for the 24 first-time recipients was 100% (mean graft survival = 11.3 months). Of the 9 regraft kidneys, 2 have failed (mean graft survival = 11.9 months) due to chronic rejection. In comparison, the 16 paired kidneys transplanted into non-6-antigen-matched recipients exhibited a 1-year graft survival of 80% versus 92% for the 33 recipients of mandatorily shared kidneys (P = 0.01). These 16 recipients were composed of more blacks (38%), fewer regrafts (6%), and most were unsensitized (75%). All 25 cadaveric donors were caucasians with very common HLA types. Thus, kidneys provided by the UNOS mandatory sharing policy had excellent allograft survival, and the recipients were largely unsensitized caucasians receiving their first kidney. The low number of blacks receiving allografts under this policy may be due to two factors. First, the histocompatibility differences between black recipients and the primarily caucasian cadaveric donor pool limit the number of kidneys available to blacks. Secondly, blacks do not have access to the best-matched kidneys, in part due to few black donors, their best source for well-matched kidneys. Thus, the mandatory sharing program is of clear benefit to the recipients of these well-matched kidneys; however, for a local program servicing a waiting list composed of 64% blacks the policy has been of limited value. In contrast, over 50% of local cadaveric transplants are into black recipients in a waiting time of 197 days, one third the national average for blacks. In conclusion, this study supports efforts to improve graft survival through matching but emphasizes the need to broaden our efforts in all areas of research and organ procurement to serve the entire recipient population, regardless of race.

RS-61443--a phase I clinical trial and pilot rescue study

RS-61443, a morpholinoethyl ester of mycophenolic acid, inhibits the synthesis of guanosine monophosphate, which plays a pivotal role in lymphocyte metabolism. The drug blocks proliferative responses of T and B lymphocytes, and inhibits antibody formation and the generation of cytotoxic T cells. In vivo, RS-61443 prolongs the survival of islet allografts in mice, heart allografts in rats, and kidney allografts in dogs. Reversal of ongoing acute rejection was demonstrated in rat heart allografts and kidney allografts in dogs. Preliminary evidence suggests that the drug prevents chronic rejection. The purpose of this study was to test the safety and tolerance in patients receiving primary cadaver kidneys. RS-61443 in doses from 100 mg/day p.o. to 3500 mg/day p.o. was given to patients in combination with cyclosporine and prednisone. Further study goals were to evaluate the pharmacokinetics of RS-61443, watch for the occurrence of opportunistic infections and acute rejection, and establish dosages for further clinical trials. Forty-eight patients were entered, with six patients in each dose group. RS-61443 was well tolerated in all dose groups, with only one adverse event possibly related to the drug (hemorrhagic gastritis). There was a statistically significant correlation between rejection episodes and dose (P = 0.022), patients with rejection episodes versus dose (P = 0.038), and number of OKT3/prednisone courses versus dose (P = 0.008). There was no overt nephrotoxicity or hepatotoxicity. Preliminary results of a rescue trial in 20 patients with kidney transplants will also be presented.

The effect of erythropoietin and blood transfusions on highly sensitized patients on a single cadaver renal allograft waiting list

The effects of EPO on transfusion requirements and HLA allosensitization were studied in a group of 145 sensitized patients on a single cadaveric renal allograft waiting list. All patients included in the study had PRA levels greater than 40% and at least six months of follow-up after the general availability of EPO. A total of 108 (74%) of these patients received EPO during the study period while 37 (26%) did not. The EPO patients had a much higher incidence of prior transfusions than the non-EPO patients (64% vs. 39% P less than 0.05). During the follow-up period, there was a marked reduction in transfusion incidence in the patients who received EPO from 64% to 14% (P less than 0.05). A lesser and nonsignificant reduction in incidence of transfusions was seen in the non-EPO-EPO patients. Analysis of PRA levels in the EPO and non-EPO groups demonstrated a reduction in PRA levels over time but there was no difference between the two groups. When the patients were divided by the need for transfusions in the follow-up period, a comparison of these two groups demonstrated significant differences. At the six-month follow-up point, patients in the nontransfused group had a significantly lower mean PRA than the transfused patients (49% vs. 62%, respectively, P less than 0.05). Furthermore, a greater number of patients in the nontransfused group had PRA declines greater than or equal to 15% compared with the nontransfused group (56/46% vs. 4/15%, respectively; P = .007). Stepwise logistic regression analysis of possible risk factors for persistent high PRA levels demonstrated that continued transfusion was the only significant factor. This study suggests that the institution of EPO therapy in sensitized patients on a single cadaveric waiting list can result in substantial reduction in the need for on-going transfusions. However, the decline in PRA levels appears to be more closely tied to the avoidance of transfusion rather than to the specific institution of EPO therapy.