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.