Deceased-donor characteristics and the survival benefit of kidney transplantation

CONTEXT

Transplantation using kidneys from deceased donors who meet the expanded criteria donor (ECD) definition (age > or =60 years or 50 to 59 years with at least 2 of the following: history of hypertension, serum creatinine level >1.5 mg/dL [132.6 micromol/L], and cerebrovascular cause of death) is associated with 70% higher risk of graft failure compared with non-ECD transplants. However, if ECD transplants offer improved overall patient survival, inferior graft outcome may represent an acceptable trade-off.

OBJECTIVE

To compare mortality after ECD kidney transplantation vs that in a combined standard-therapy group of non-ECD recipients and those still receiving dialysis.

DESIGN, SETTING, AND PATIENTS

Retrospective cohort study using data from a US national registry of mortality and graft outcomes among kidney transplant candidates and recipients. The cohort included 109,127 patients receiving dialysis and added to the kidney waiting list between January 1, 1995, and December 31, 2002, and followed up through July 31, 2004.

MAIN OUTCOME MEASURE

Long-term (3-year) relative risk of mortality for ECD kidney recipients vs those receiving standard therapy, estimated using time-dependent Cox regression models.

RESULTS

By end of follow-up, 7790 ECD kidney transplants were performed. Because of excess ECD recipient mortality in the perioperative period, cumulative survival did not equal that of standard-therapy patients until 3.5 years posttransplantation. Long-term relative mortality risk was 17% lower for ECD recipients (relative risk, 0.83; 95% confidence interval, 0.77-0.90; P<.001). Subgroups with significant ECD survival benefit included patients older than 40 years, both sexes, non-Hispanics, all races, unsensitized patients, and those with diabetes or hypertension. In organ procurement organizations (OPOs) with long median waiting times (>1350 days), ECD recipients had a 27% lower risk of death (relative risk, 0.73; 95% confidence interval, 0.64-0.83; P<.001). In areas with shorter waiting times, only recipients with diabetes demonstrated an ECD survival benefit.

CONCLUSIONS

ECD kidney transplants should be offered principally to candidates older than 40 years in OPOs with long waiting times. In OPOs with shorter waiting times, in which non-ECD kidney transplant availability is higher, candidates should be counseled that ECD survival benefit is observed only for patients with diabetes.

Determinants of discard of expanded criteria donor kidneys: impact of biopsy and machine perfusion

We examined factors associated with expanded criteria donor (ECD) kidney discard. Scientific Registry of Transplant Recipients (SRTR)/Organ Procurement and Transplantation Network (OPTN) data were examined for donor factors using logistic regression to determine the adjusted odds ratio (AOR) of discard of kidneys recovered between October 1999 and June 2005. Logistic and Cox regression models were used to determine associations with delayed graft function (DGF) and graft failure. Of the 12,536 recovered ECD kidneys, 5139 (41%) were discarded. Both the performance of a biopsy (AOR = 1.21, p = 0.02) and the degree of glomerulosclerosis (GS) on biopsy were significantly associated with increased odds of discard. GS was not consistently associated with DGF or graft failure. The discard rate of pumped ECD kidneys was 29.7% versus 43.6% for unpumped (AOR = 0.52, p < 0.0001). Among pumped kidneys, those with resistances of 0.26-0.38 and >0.38 mmHg/mL/min were discarded more than those with resistances of 0.18-0.25 mmHg/mL/min (AOR = 2.5 and 7.9, respectively). Among ECD kidneys, pumped kidneys were less likely to have DGF (AOR = 0.59, p < 0.0001) but not graft failure (RR = 0.9, p = 0.27). Biopsy findings and machine perfusion are important correlates of ECD kidney discard; corresponding associations with graft failure require further study.

Diabetes mellitus after renal transplantation: as deleterious as non-transplant-associated diabetes?

BACKGROUND

Despite use of lower doses of corticosteroid hormones after renal allotransplantation in the era of cyclosporine and tacrolimus, posttransplant diabetes mellitus remains a common clinical problem.

METHODS

We prospectively investigated the effect of posttransplant diabetes on long-term (mean follow-up, 9.3+/-1.5 years) graft and patient survival in the 11.8% of our renal transplant population (n = 40) who developed diabetes after kidney transplantation, and we compared outcome in 38 randomly chosen nondiabetic control patients who had received transplants concurrently.

RESULTS

Twelve-year graft survival in diabetic patients was 48%, compared with 70% in control patients (P = 0.04), and Cox's regression analysis revealed diabetes to be a significant predictor of graft loss (P = 0.04, relative risk = 3.72) independent of age, sex, and race. Renal function at 5 years as assessed by serum creatinine level was inferior in diabetic patients compared to control patients (2.9+/-2.6 vs. 2.0+/-0.07 mg/dl, P = 0.05). Two diabetic patient who experienced graft loss had a clinical course and histological features consistent with diabetic nephropathy; other diabetes-related morbidity in patients with posttransplant diabetes included ketoacidosis, hyperosmolar coma or precoma, and sensorimotor peripheral neuropathy. Patient survival at 12 years was similar in diabetic and control patients (71% vs. 74%).

CONCLUSIONS

Posttransplant diabetes mellitus is associated with impaired long-term renal allograft survival and function, complications similar to those in non-transplant-associated diabetes may occur in posttransplant diabetes, and, hence, as in non-transplant-associated diabetes, tight glycemic control may also be warranted in patients with posttransplant diabetes.

Effect of changing the priority for HLA matching on the rates and outcomes of kidney transplantation in minority groups

BACKGROUND

HLA typing and the time a patient has spent on the waiting list are the primary criteria used to allocate cadaveric kidneys for transplantation in the United States. Candidates with no HLA-A, B, and DR mismatches are given top priority, followed by candidates with the fewest mismatches at the HLA-B and DR loci; this policy contributes to a higher transplantation rate among whites than nonwhites. We hypothesized that changing this allocation policy would affect graft survival and the racial balance among transplant recipients.

METHODS

We estimated the relative rates of kidney transplantation according to race resulting from the current allocation policy and racial differences in HLA antigen profiles, using a Cox model for the time from placement on the waiting list to transplantation. Another model, also adjusted for HLA-B and DR antigen profiles, estimated the relative rates of kidney transplantation that would result if the distribution of these antigen profiles were identical among the racial and ethnic groups. We also investigated the effect of HLA matching on the risk of graft failure, using a Cox model for the time from the first transplantation to graft failure. The results of the two analyses were used to estimate the change in the racial balance of transplantation and graft-failure rates that would result from the elimination of HLA-B matching or HLA-B and DR matching as a means of assigning priority.

RESULTS

Eliminating the HLA-B matching as a priority while maintaining HLA-DR matching as a priority would decrease the number of transplantations among whites by 4.0 percent (166 fewer transplantations over a one-year period), whereas it would increase the number among nonwhites by 6.3 percent and increase the rate of graft loss by 2.0 percent.

CONCLUSIONS

Removing HLA-B matching as a priority for the allocation of cadaveric kidneys could reduce the existing racial imbalance by increasing the number of transplantations among nonwhites, with only a small increase in the rate of graft loss.

The effect of kidney size on cadaveric renal allograft outcome

Chronic rejection is the commonest cause of long-term renal allograft loss. Though immunologic factors are thought dominant in its pathogenesis, nonimmunologic factors, in particular, hyperfiltration damage related to reduced renal mass, have also been proposed as factors in the causation of chronic allograft rejection. We assessed the influence of renal size on graft survival and function in all cyclosporine-treated cadaver donor adult renal allograft recipients engrafted at a single center between June 1989 and July 1994, whose grafts functioned for > or = to 3 months (n=169). Patients were divided into 4 groups based on the ratio of kidney volume to recipient body surface area (volume/BSA) (ml/m2), and outcome in groups compared by methods including Cox's proportional hazards and Kaplan-Meier analysis. No significant differences between groups existed for serum creatinine levels, presence of significant proteinuria, or 1- and 5-year graft survival. There was no correlation between volume/BSA and either serum creatinine or degree of proteinuria at 3, 6, 12, 36, and 60 months posttransplant. Volume/BSA was similar in patients with good or poor renal function (58 +/-21 vs. 56 +/- 28 ml/m2), with or without significant proteinuria (57 +/- 24 vs. 60 +/- 25 ml/m2) or in patients who lost their grafts to chronic rejection compared with those with stable allograft function (64 +/- 34 vs. 59 +/- 24 ml/m2). Volume/BSA was not a predictor of graft survival on multivariate regression. We conclude that donor kidney size has no apparent effect on cadaveric renal allograft outcome in the short and intermediate-term, suggesting that close matching of donor kidney size to recipient size is not presently indicated.

The kidney in liver transplantation

Renal dysfunction often complicates the course of liver transplant recipients. Preoperative renal dysfunction, including hepatorenal syndrome (HRS) may be present. Assessment of renal function in the pretransplant patient with end-stage liver disease is fraught with pitfalls. Direct measurement of GFR by a method other than creatinine clearance is recommended wherever possible. Preoperative renal biopsy should also be considered in those patients with renal dysfunction in whom the diagnosis of HRS is not definite. With the routine use of veno venous bypass, renal perfusion is maintained and intraoperative events generally do not play a significant role in the development of postoperative dysfunction. Postoperatively immunosuppressive medications such as CsA or FK506 account for most of the renal dysfunction that is observed. Other factors such as graft dysfunction, sepsis, and nephrotoxic drugs may also participate in renal impairment. The exact mechanism of cyclosporine or FK506 nephrotoxicity remains unknown. In liver transplant recipients, no convincing therapeutic strategies exist to combat nephrotoxicity other than dose reduction of immunosuppressive therapy. Patients with HRS can be successfully treated by liver transplantation with recovery of renal function and with patient survival rates comparable to recipients without HRS, despite increased morbidity.

Unemployment in inner-city renal transplant recipients: predictive and sociodemographic factors

Studies of dialysis patients report unemployment rates of 60% to 75%; however, it is generally believed that following transplantation, improvement in well-being and removal of time constraints imposed by the dialytic regimen afford improvement in employment status. We studied 58 stable renal transplant recipient attending an outpatient transplant clinic by questionnaire, administered anonymously. Only 25 (43%) of the patients were currently employed. Employed and unemployed patients did not differ when compared for age, gender, race, cause of renal disease, type of transplant or prior dialysis, time on dialysis or time since transplantation, years of education, or prestige score or classification ("blue collar" v "white collar") of prior job. In the employed group, 24 (96%) patients had worked before developing kidney disease compared with 23 (70%) patients in the unemployed group (P < 0.05). While on dialysis, 19 (79%) of the employed patients continued working compared with 10 (30%) of the unemployed patients (P < 0.005). Major reasons for discontinuing work after starting dialysis for both groups were subjective illness (feeling too sick, 51%), followed by interference of the dialysis regimen with time necessary for work (32%). Only 15% of the previously employed patients did not work after transplantation because of feeling too sick. By multiple logistic regression, the strongest predictors of employment posttransplant were being more than 1 year posttransplant (odds ratio, 2.35; 95% confidence interval, 1.01 to 5.5) and having been employed before transplantation (odds ratio, 3.79; 95% confidence interval, 1.60 to 9.02). Over half of the unemployed patients (20 [61%]) expressed interest in job training. Eighty percent to 90% of patients in both groups were insured by Medicare, with the second greatest number insured by Medicaid. Of the 15 unemployed patients insured by Medicaid, 67% reported that their decision not to work was related to fear of losing Medicaid benefits because they could not afford medications without it. Despite no difference in actual type of insurance carried, 17 (51%) of the unemployed patients believed their health insurance coverage was inadequate compared with four (12%) of the employed patients (P = 0.005, chi-squared test). Unemployment remains a significant problem for our population of inner-city renal transplant recipients. Attention to job retention or retraining during the early renal disease and dialysis therapy period may promote better rehabilitation following transplantation. However, for this population, with limited employment opportunities, removal of disincentives to work, including loss of Insurance and Inability to pay for medications, will be necessary before we can provide optimal rehabilitation for renal transplant recipients from all social strata.

First Report on the OPTN National Variance: Allocation of A2 /A2 B Deceased Donor Kidneys to Blood Group B Increases Minority Transplantation

In 2002, the Organ Procurement and Transplantation Network (OPTN) Minority Affairs Committee (MAC) implemented a national, prospective, "variance of practice" to allow deceased donor, ABO blood group incompatible, A2 antigen, kidney transplantation into blood group B recipients; outcomes of this cohort were compared to ABO compatible recipients. The goal of the variance was to increase the number of transplants to B candidates without negatively impacting survival or compromising system equity. Only B recipients with low anti-A IgG titers (<1:8) were eligible to receive these kidneys. Across eight participating Donation Service Areas (DSA), there were 101 A2 /A2 B to B transplants through 12/31/11, of which the majority of the recipients (61%) were ethnic minorities. At 12, 24, and 36 months, Kaplan-Meier graft survival rates for the B recipients of A2 /A2 B kidneys were 95.0%, 90.6%, and 85.4%, respectively, comparable to outcomes for B recipients of B kidneys, 92.6%, 87.9%, and 82.5%, respectively (p-value = 0.48). Five DSAs increased the proportion of B transplants during 41 months postvariance, with a lesser proportional decrease in blood group A transplants. The data support the proposition that this allocation algorithm may provide a robust mechanism to increase access of blood group B minority candidates to kidney transplantation.

Kidney and pancreas transplantation

Data from the Scientific Registry of Transplant Recipients offer a unique and comprehensive view of US trends in kidney and pancreas waiting list characteristics and outcomes, transplant recipient and donor characteristics, and patient and allograft survival. Important findings from our review of developments during 2002 and the decade's transplantation trends appear below. The kidney waiting list has continued to grow, increasing from 47,830 in 2001 to 50,855 in 2002. This growth has occurred despite the increasing importance of living donor transplantation, which rose from 28% of total kidney transplants in 1993 to 43% in 2002. Policies and procedures to expedite the allocation of expanded criteria donor (ECD) kidneys were developed and implemented during 2002, when 15% of deceased donor transplants were performed with ECD kidneys. Unadjusted 1- and 5-year deceased donor kidney allograft survivals were 81% and 51% for ECD kidney recipients, and 90% and 68% for non-ECD kidney recipients, respectively. Although more patients have been placed on the simultaneous kidney-pancreas waiting list, the number of these transplants dropped from a peak of 970 in 1998 to 905 in 2002. This decline may be due to competition for organs from increasing numbers of isolated pancreas and islet transplants.

Prevalence of Central Vein Stenosis in Patients Referred for Vein Mapping

BACKGROUND AND OBJECTIVES

Central vein stenosis is considered to be common in patients on hemodialysis but its exact prevalence is not known. In this study, we report the prevalence of central vein stenosis in patients with CKD referred for vein mapping.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a retrospective study of adult patients who had bilateral upper extremity venographic vein mapping from September 1, 2011 to December 31, 2015. Patients with and without stenosis were compared for differences in clinical or demographic characteristics. Multiple logistic regression was used to identify independent associations between patient characteristics and central vein stenosis.

RESULTS

There were 525 patients who underwent venographic vein mapping during the study period, 27% of whom were referred before initiation of hemodialysis. The mean age (±SD) and body mass index were 59 (±15) years and 28 (±7), respectively. Women accounted for 45% of patients; 82% were black. The prevalence of central vein stenosis was 10% (95% confidence interval [95% CI], 8% to 13%) for the whole group, and 13% (95% CI, 10% to 17%) among patients with tunneled central venous dialysis catheters. Current use of tunneled hemodialysis catheters (odds ratio [OR], 14.5; 95% CI, 3.25 to 65.1), presence of cardiac rhythm devices (OR, 5.07; 95% CI, 1.82 to 14.11), previous history of fistula or graft (OR, 3.28; 95% CI, 1.58 to 6.7), and history of previous kidney transplant (OR, 18; 95% CI, 4.7 to 68.8) were independently associated with central vein stenosis.

CONCLUSIONS

In this population, the prevalence of central vein stenosis was 10% and was clustered among those with tunneled hemodialysis catheters, cardiac rhythm device, and previous history of dialysis access or transplant.

Factors limiting the rate of living-related kidney donation to children in an inner city setting

A recent review of our center experience revealed that only 38% of our pediatric renal transplants come from living-related donors (LRD), which is 11% lower than the national average. The present study was designed to identify factors that limit the availability of LRD in our population pool. Retrospective chart reviews and subsequent telephone interviews were conducted with parents of all children who received renal replacement therapy (RRT) at our institution from 1990 to 1999. The availability of parents and their willingness to donate a kidney were noted. Self-reported willingness was defined as the verbal expression of a desire to donate. Firm willingness was defined as the completion of the steps necessary for donation, unless excluded by the medical team. Factors that may impact the ability to donate, such as donor age, ethnicity, religion, educational attainment, employment, and presence of other siblings younger than 18 yr of age, were evaluated. Statistical analyses were performed using the Student's t-test and chi-square analysis. Significant results were entered into a single-step multiple regression analysis. Sixty children were identified with RRT, of whom 60% were Blacks, 30% Hispanics, 7% Caucasians, and 3% Asian. Fifty-five mothers were available for interview. Forty-four mothers reported a desire to donate, nine were unwilling to donate, and two were undecided. However, only 35 attended for screening. Only 30 fathers were available and, of these, 27 reported willingness to donate, yet only 20 attended for screening. Seventy-four per cent (26 out of 35) of mothers screened and 55% (11 out of 20) of fathers screened were medically unsuitable for kidney donation. Nineteen potential donors had hypertension, diabetes and/or obesity, seven had renal disease, four had anemia, two had hepatitis C, and five had other conditions. Expressed unwillingness to donate was associated with a greater number of children (3.1 compared to 1.5 children in addition to the child with end-stage renal disease [ESRD]) (odds ratio 2.91, p < 0.05) and employment (26.3% vs. 4.0%, p < 0.05) (odds ratio 31.2, p = 0.05). Comparing mothers who were firmly willing to donate with mothers who did not complete screening and evaluation, unwilling mothers had, likewise, a greater number of children (2.9 vs. 1.2 in addition to the child with ESRD) (odds ratio 3.23, p < 0.01) and a greater number of years of education (12.4 vs. 10.4) (odds ratio 2.14, p < 0.05). Hence, the availability of living kidney donors for our inner city children is severely limited by a high rate of single parenthood and a high rate of comorbid conditions in the parental donor pool. Furthermore, there is a diminished capacity of the available parent, particularly the mother, to donate as she tends to have numerous other dependents.

Successful treatment of post-renal transplant Kaposi's sarcoma with paclitaxel

Kaposi's sarcoma (KS) is a complication of immunosuppressive therapy for renal transplant recipients. Treatment is usually withdrawal of immunosuppression; nonresponders often receive chemotherapy. Successful treatment with single agent paclitaxel (PTX) has been documented in only one patient. We report two patients with generalized cutaneous, and visceral KS, which progressed despite withdrawal of immunosuppressive therapy, and were treated with weekly PTX. Both patients' KS regressed completely after four courses of PTX, and remained in remission for > 1 year. PTX may be important in the treatment of post-transplant KS resistant to withdrawal of immunosuppressive therapy.

Determinants of type of initial hemodialysis vascular access

Vascular access thrombosis is more common with polytetrafluoroethylene (PTFE) grafts than with native arteriovenous fistulae (AVF). Recent studies report an unexplained excess vascular access morbidity in women on hemodialysis. We studied 92 consecutive end-stage renal disease (ESRD) patients receiving their first permanent hemodialysis vascular access at initiation of hemodialysis to identify variables that determine assignment of either a PTFE graft or a native AVF. Independent variables included: age, gender, race, etiology of ESRD, and whether or not access surgery was electively planned before need for dialytic therapy. The 51 women and 41 men included 65 blacks, 13 Hispanics, 11 whites, and 3 Orientals aged 50 +/- (SD) 16 years. Of the 92 subjects, 54 (59%) received an AVF, while 38 (41%) received a PTFE graft. 36 (94%) of 38 PTFE grafts were placed in the upper arm as compared with 9 (17%) of 54 AVF (p = 0.0001). Also, 45 (83%) of 54 AVF were placed in the forearm as compared with only 2 (6%) of 38 PTFE grafts (p = 0.0001). Women were more likely to receive a PTFE graft - 28 (55%) of 51 - than men - 10 (24%) of 41 (p = 0.003). By contrast, men were more likely to get an AVF - 31 (76%) of 41 - than women - 23 (45 %) of 51 (p = 0.003). The log linear analysis confirmed that this finding was significant (p = 0.0018) for the coefficient of interaction between gender and type of vascular access. No other independent variable had a significant relationship with type of vascular access. We conclude that women with ESRD are more likely to receive a PTFE graft for hemodialysis, while men are more likely to get an AVF. These findings may explain, in part, the reported excess vascular access morbidity in women on hemodialysis.

Poor kidney allograft survival associated with positive B cell - Only flow cytometry cross matches: a ten year single center study

The presence of donor specific antibody (DSA) to class 1 or class 2 HLA as detected respectively in T cell or B cell - only flow cytometry cross matches (FCXMs) are risk factors for renal allograft survival, though the comparative risk of these XMs has not been definitively established. Allograft survival and FCXM data in 624 microcytotoxicity (CDC) XM negative kidney transplants were evaluated. Short and long term allograft survival was significantly less in recipients with T(-) B(+) FCXMs (1 year, 74%, 10 year, 58%) compared to T(+) B(+) FCXMs (1 year, 84%, 10 year, 68%) and to T(-) B(-) FCXM (1 year, 90%, 10 year, 85%). Risk factors were positive FCXM, deceased donor (DD) transplantation and donor age, but not race, gender, recipient age or previous transplant. Recipients with T(-) B(+) and T(+) B(+) FCXMs were at 4.5 and 2.5 fold greater risk, respectively, of DD allograft failure compared to patients with T(-) B(-) FCXMs. The quantitative value of FCXM did not correlate with the duration of graft survival. We conclude that patients with DSA to class 2 HLA have a greater risk of early and late allograft failure compared to patients with DSA to class 1 HLA.

Aminoguanidine prolongs survival in azotemic-induced diabetic rats

Toxic effects of hyperglycemia-induced advanced glycosylated end products (AGEs) may explain some vasculopathic complications of diabetes. Aminoguanidine, a known inhibitor of AGE formation, was administered by gavage to Sprague-Dawley streptozotocin-induced diabetic rats made azotemic by surgical reduction of renal mass. All rats became hyperglycemic. Renal ablation caused renal insufficiency, as evidenced by markedly reduced endogenous creatinine clearances at days 7 and 14. Aminoguanidine-treated rats had significantly (P < 0.04) superior survival to that of untreated azotemic diabetic rats. We infer from the extended life in a rat model of uremia in diabetic nephropathy that aminoguanidine may prove beneficial in human diabetes.

Effects of diabetes and uremia on mesenteric vascular reactivity

BACKGROUND

Diabetes and uremia are comorbid conditions that have significant effects on cardiovascular physiology. These studies were designed to examine the effects of diabetes and uremia on vascular reactivity.

METHODS

Sprague-Dawley rats were divided into control (C), diabetic (D), uremic (U), and diabetic/uremic (D + U) groups. Diabetes (D, D + U groups) was induced with an injection of streptozotocin. Uremic (U, D + U groups) was produced by seven-eighths nephrectomy. Serum glucose, blood urea nitrogen, creatinine, creatinine clearance, and protein excretion were measured at baseline and before microvascular studies at 4 or 8 weeks after injection. Vascular reactivity was studied in isolated, pressurized, and superfused segments of mesenteric arterioles (300 microns). Changes in internal vessel diameter were measured in response to phenylephrine (10(-8) to 10(-4) mol/L), acetylcholine (10(-9) to 10(-5) mol/L), and nitroprusside (10(-9) to 10(-2) mol/L).

RESULTS

Results at 4 and 8 weeks were similar in all groups. Vasoconstrictor responses to phenylephrine and endothelium-independent vasodilator responses to nitroprusside were not altered in any experimental group. Endothelium-dependent vasodilator responses to acetylcholine were significantly depressed in both diabetic groups (D and D + U, p < 0.01 versus control), and there were no differences between the two diabetic groups.

CONCLUSIONS

Streptozotocin-induced diabetes results in impairment of endothelial-dependent (nitric oxide mediated) vasodilator responses in mesenteric resistance vessels, which are unaffected by coexisting uremia. Uremia has little effect on mesenteric vascular reactivity in this model.

Impact of human leukocyte antigen-DR mismatch status on kidney graft survival in a predominantly African-American population under the newer immunosuppressive era

BACKGROUND

Human leukocyte antigen (HLA)-DR has been shown to be immunogenic and associated with poor long-term graft function. However, under potent induction immunosuppression with antithymocyte globulin, the impact of the HLA-DR remains unclear.

METHOD

We reviewed 672 renal transplant recipients who received their transplants between 1998 and 2007. All patients received antithymocyte globulin as induction therapy followed by tacrolimus + prednisone + mycophenolate mofetil for maintenance immunosuppression. We divided the patients into three groups according to HLA-DR mismatch status (zero, one, or two mismatches).

RESULTS

The three groups were different in total number of mismatches, deceased donor transplant, and delayed graft function, respectively. By Kaplan-Meier survival analysis, actuarial graft survival was significantly lower in the HLA-DR two mismatches group (72%) compared to HLA-DR zero mismatches group (78.5%) or HLA-DR one mismatch group (78.5%; P = .05, by log-rank test). Using Cox regression analysis, the risk of graft failure with two HLA-DR mismatches as compared with zero HLA-DR mismatches was 1.6 (95% confidence interval = 1.0-2.44, P = .049). When adjusted for age, wait time, race, type of transplant, retransplant status, T-cell flow crossmatch, delayed graft function, acute rejection, HLA-A and HLA-B, the effect of HLA-DR on survival was not significant (P = .55).

CONCLUSION

The independent effect of HLA-DR mismatches on adverse graft survival is diminished under potent antibody induction and maintenance immunosuppression in our predominantly African-American population.

Delayed thromboembolectomy for subacute limb ischemia

Arterial embolization frequently requires immediate operative intervention. Occasionally, embolic events produce subacute limb ischemia that may not be recognized as thromboembolic in origin. In October 1988, a prospective policy to attempt thromboembolectomy rather than infrainguinal bypass in all patients with delayed presentation of lower limb thromboembolism was initiated at our institution. Seven limbs in five patients were identified by history, physical examination, noninvasive study, and/or angiography as ischemic due to thromboembolism, which occurred from 3 to 10 weeks prior to presentation. Six of seven limbs were studied angiographically, and all seven were treated by femoral and/or popliteal thromboembolectomy with limb salvage. Six of seven limbs were restored to normal arterial hemodynamics as assessed by intra- and postoperative noninvasive study. One limb in a patient continued to have minimal residual occlusive disease that was recognized preoperatively. In all cases, chronic and fresh thromboemboli were found at surgery and confirmed by pathology. Chronic thromboembolism seems to be an underrecognized event. Limb salvage can be achieved readily even if extensive delay in diagnosis is present. Using preoperative angiography and intraoperative noninvasive techniques to measure the success of revascularization, as well as avoiding, when possible, complex infrainguinal reconstruction in these high-risk patients allows for an aggressive approach to limb salvage with gratifying results.