Walter K. Kremers

Hyponatremia and mortality among patients on the liver-transplant waiting list.

BACKGROUND Under the current liver-transplantation policy, donor organs are offered to patients with the highest risk of death. METHODS Using data derived from all adult candidates for primary liver transplantation who were registered with the Organ Procurement and Transplantation Network in 2005 and 2006, we developed and validated a multivariable survival model to predict mortality at 90 days after registration. The predictor variable was the Model for End-Stage Liver Disease (MELD) score with and without the addition of the serum sodium concentration. The MELD score (on a scale of 6 to 40, with higher values indicating more severe disease) is calculated on the basis of the serum bilirubin and creatinine concentrations and the international normalized ratio for the prothrombin time. RESULTS In 2005, there were 6769 registrants, including 1781 who underwent liver transplantation and 422 who died within 90 days after registration on the waiting list. Both the MELD score and the serum sodium concentration were significantly associated with mortality (hazard ratio for death, 1.21 per MELD point and 1.05 per 1-unit decrease in the serum sodium concentration for values between 125 and 140 mmol per liter; P<0.001 for both variables). Furthermore, a significant interaction was found between the MELD score and the serum sodium concentration, indicating that the effect of the serum sodium concentration was greater in patients with a low MELD score. When applied to the data from 2006, when 477 patients died within 3 months after registration on the waiting list, the combination of the MELD score and the serum sodium concentration was considerably higher than the MELD score alone in 32 patients who died (7%). Thus, assignment of priority according to the MELD score combined with the serum sodium concentration might have resulted in transplantation and prevented death. CONCLUSIONS This population-wide study shows that the MELD score and the serum sodium concentration are important predictors of survival among candidates for liver transplantation.

Identifying Specific Causes of Kidney Allograft Loss

The causes of kidney allograft loss remain unclear. Herein we investigated these causes in 1317 conventional kidney recipients. The cause of graft loss was determined by reviewing clinical and histologic information the latter available in 98% of cases. During 50.3 ± 32.6 months of follow‐up, 330 grafts were lost (25.0%), 138 (10.4%) due to death with function, 39 (2.9%) due to primary nonfunction and 153 (11.6%) due to graft failure censored for death. The latter group was subdivided by cause into: glomerular diseases (n = 56, 36.6%); fibrosis/atrophy (n = 47, 30.7%); medical/surgical conditions (n = 25, 16.3%); acute rejection (n = 18, 11.8%); and unclassifiable (n = 7, 4.6%). Glomerular pathologies leading to failure included recurrent disease (n = 23), transplant glomerulopathy (n = 23) and presumed nonrecurrent disease (n = 10). In cases with fibrosis/atrophy a specific cause(s) was identified in 81% and it was rarely attributable to calcineurin inhibitor (CNI) toxicity alone (n = 1, 0.7%). Contrary to current concepts, most cases of kidney graft loss have an identifiable cause that is not idiopathic fibrosis/atrophy or CNI toxicity. Glomerular pathologies cause the largest proportion of graft loss and alloinmunity remains the most common mechanism leading to failure. This study identifies targets for investigation and intervention that may result in improved kidney transplantation outcomes.

Liver Transplantation with Neoadjuvant Chemoradiation is More Effective than Resection for Hilar Cholangiocarcinoma

Objective:Compare survival after neoadjuvant therapy and liver transplantation with survival after resection for patients with hilar CCA. Summary Background Data:We developed a protocol combining neoadjuvant radiotherapy, chemosensitization, and orthotopic liver transplantation for patients with operatively confirmed stage I and II hilar CCA in 1993. Since then, patients with unresectable CCA or CCA arising in the setting of PSC have been enrolled in the transplant protocol. Patients with tumors amenable to resection have undergone excision of the extrahepatic duct with lymphadenectomy and liver resection. Methods:We reviewed our experience between January 1993 and August 2004 and compared patient survival between the treatment groups. Results:Seventy-one patients entered the transplant treatment protocol and 38 underwent liver transplantation. Fifty-four patients were explored for resection. Twenty-six (48%) underwent resection, and 28 (52%) had unresectable disease. One-, 3-, and 5-year patient survival were 92%, 82%, and 82% after transplantation and 82%, 48%, and 21% after resection (P = 0.022). There were fewer recurrences in the transplant patients (13% versus 27%). Conclusions:Liver transplantation with neoadjuvant chemoradiation achieved better survival with less recurrence than conventional resection and should be considered as an alternative to resection for patients with localized, node-negative hilar CCA.

Terminal complement inhibition decreases antibody-mediated rejection in sensitized renal transplant recipients.

Sensitized renal transplant recipients with high levels of donor‐specific alloantibody (DSA) commonly develop antibody‐mediated rejection (AMR), which may cause acute graft loss or shorten allograft survival. We examined the efficacy of terminal complement inhibition with the humanized anti‐C5 antibody, eculizumab, in the prevention AMR in renal transplant recipients with a positive crossmatch against their living donor. The incidence of biopsy‐proven AMR in the first 3 months posttransplant in 26 highly sensitized recipients of living donor renal transplants who received eculizumab posttransplant was compared to a historical control group of 51 sensitized patients treated with a similar plasma exchange (PE)‐based protocol without eculizumab. The incidence of AMR was 7.7% (2/26) in the eculizumab group compared to 41.2% (21/51) in the control group (p = 0.0031). Eculizumab also decreased AMR in patients who developed high levels of DSA early after transplantation that caused proximal complement activation. With eculizumab, AMR episodes were easily treated with PE reducing the need for splenectomy. On 1‐year protocol biopsy, transplant glomerulopathy was found to be present in 6.7% (1/15) eculizumab‐treated recipients and in 35.7% (15/42) of control patients (p = 0.044). Inhibition of terminal complement activation with eculizumab decreases the incidence of early AMR in sensitized renal transplant recipients (ClincalTrials.gov number NCT006707).

Evolution of Causes and Risk Factors for Mortality Post-Liver Transplant: Results of the NIDDK Long-Term Follow-Up Study

Although mortality rates following liver transplantation (LT) are well described, there is a lack of detailed, prospective studies determining patterns of and risk factors for long‐term mortality. We analyzed the multicenter, prospectively obtained The National Institute of Diabetes and Digestive and Kidney Diseases LT Database of 798 transplant recipients from 1990 to 1994 (follow‐up 2003). Overall, 327 recipients died. Causes of death >1 year: 28% hepatic, 22% malignancy, 11% cardiovascular, 9% infection, 6% renal failure. Renal‐related death increased dramatically over time. Risk factors for death >1 year (univariate): male gender, age/decade, pre‐LT diabetes, post‐LT diabetes, post‐LT hypertension, post‐LT renal insufficiency, retransplantation >1 year, pre‐LT malignancy, alcoholic disease (ALD) and metabolic liver disease, with similar risks noted for death >5 years. Hepatitis C, retransplantation, post‐LT diabetes, hypertension and renal insufficiency were significant risk factors for liver‐related death. Cardiac deaths associated with age, male gender, ALD, cryptogenic disease, pre‐LT hypertension and post‐LT renal insufficiency. In summary, the leading causes of late deaths after transplant were graft failure, malignancy, cardiovascular disease and renal failure. Older age, diabetes and renal insufficiency identified patients at highest risk of poor survival overall. Diligent management of modifiable post‐LT factors including diabetes, hypertension and renal insufficiency may impact long‐term mortality.

Addition of serum sodium into the MELD score predicts waiting list mortality better than MELD alone

In this study, we investigated the prognostic value of serum sodium and hyponatremia (≤130 mEq/L) in 262 cirrhotic patients consecutively listed, 19 of which died (7%), 175 survived (67%), and 68 underwent liver transplantation (26%) during 3 months of follow‐up. Hyponatremia was present in 63% of patients who died, compared to 13% of those who survived (P < .001), whereas the proportion with elevated creatinine (≥1.4 mg/dL) was low and similar in both groups (10.5 vs. 3%). Prevalence of hyponatremia was higher than that of elevated serum creatinine across all model for end‐stage liver disease (MELD) categories. Using logistic regression, hyponatremia and serum sodium were significant predictors of mortality with concordance statistics (c‐statistics) .753 for hyponatremia, .784 for sodium, .894 for MELD, .905 for MELD plus hyponatremia (P = .006 vs. MELD alone), and .908 for MELD plus serum sodium (P = .026 vs. MELD alone). Risk of death across all MELD scores was higher for patients with hyponatremia than without hyponatremia. Cox regression considering data within 6 months of follow‐up yielded qualitatively similar results, with hyponatremia being a significant predictor of greater mortality risk with an odds ratio of 2.65 (P = .015). Each increase of 1 mEq/L of serum sodium level was associated with a decreased odds ratio of .95 (P = .048). Our results indicate that hyponatremia appears to be an earlier and more sensitive marker than serum creatinine to detect renal impairment and / or circulatory dysfunction in patients with advanced cirrhosis. In conclusion, addition of serum sodium to MELD identified a subgroup of patients with poor outcome in a more efficient way than MELD alone and significantly increased the efficacy of the score to predict waitlist mortality. (Liver Transpl 2005;11:336–343.)

Complete avoidance of calcineurin inhibitors in renal transplantation : A randomized trial comparing sirolimus and tacrolimus

Calcineurin inhibitors have decreased acute rejection and improved early renal allograft survival, but their use has been implicated in the development of chronic nephrotoxicity. We performed a prospective, randomized trial in kidney transplantation comparing sirolimus‐MMF‐prednisone to tacrolimus‐MMF‐prednisone. Eighty‐one patients in the sirolimus group and 84 patients in the tacrolimus group were enrolled (mean follow‐up = 33 months; range 13–47 months). At 1 year, patient survival was similar in the groups (98% with sirolimus, 96% with tacrolimus; p = 0.42) as was graft survival (94% sirolimus vs. 92% tacrolimus, p = 0.95). The incidence of clinical acute rejection was 10% in the tacrolimus group and 13% in the sirolimus group (p = 0.58). There was no difference in mean GFR measured by iothalamate clearance between the tacrolimus and sirolimus groups at 1 year (61 ± 19 mL/min vs. 63 ± 18 mL/min, p = 0.57) or 2 years (61 ± 17 mL/min vs. 61 ± 19 mL/min, p = 0.84). At 1 year, chronicity using the Banff schema showed no difference in interstitial, tubular or glomerular changes, but fewer chronic vascular changes in the sirolimus group. This study shows that a CNI‐free regimen using sirolimus‐MMF‐prednisone produces similar acute rejection rates, graft survival and renal function 1–2 years after transplantation compared to tacrolimus‐MMF‐prednisone.

Wound-healing complications after kidney transplantation: a prospective, randomized comparison of sirolimus and tacrolimus.

Background. Sirolimus has been associated with an increased risk of wound-healing complications in several retrospective analyses. The authors compared the rates of wound-healing complications in renal allograft recipients in a prospective, randomized trial of sirolimus-mycophenolate mofetil-prednisone versus tacrolimus-mycophenolate mofetil-prednisone. Methods. All patients received antithymocyte globulin induction. In the first phase of the study, patients (n=77) were included regardless of body mass index (BMI). In the second phase (n=46 patients), the authors excluded patients with a BMI greater than 32 kg/m2, and the target trough sirolimus level was lowered to 10 to 15 ng/mL (previously 15–20 ng/mL). Multivariate logistic regression analyses were performed to identify predictors of wound complications. Results. Fifty-nine patients received tacrolimus and 64 received sirolimus and were included in subsequent analyses. The incidence of complications was 8% (5 of 59) in the tacrolimus group and 47% (30 of 64) in the sirolimus group (P <0.0001). Rates of perigraft fluid collections, superficial wound infections, and incisional herniae were significantly higher in the sirolimus group. Multivariate logistic regression showed only sirolimus (P =0.0001) and BMI (P =0.0021) to independently correlate with complications. In the first phase of the study, the wound complication rate in the sirolimus group was 55% (21 of 38 patients). After excluding obese recipients and decreasing the target sirolimus level, the wound complication rate in the sirolimus group was 35% (9 of 26 patients; P =0.1040). Conclusions. The use of sirolimus-based immunosuppressive regimens leads to a higher incidence of wound-healing complications and will require new approaches to patient selection and management to decrease their incidence.

The association between age and nephrosclerosis on renal biopsy among healthy adults.

BACKGROUND Chronic kidney disease is common with older age and is characterized on renal biopsy by global glomerulosclerosis, tubular atrophy, interstitial fibrosis, and arteriosclerosis. OBJECTIVE To see whether the prevalence of these histologic abnormalities in the kidney increases with age in healthy adults and whether histologic findings are explained by age-related differences in kidney function or chronic kidney disease risk factors. DESIGN Cross-sectional study. SETTING Mayo Clinic, Rochester, Minnesota, from 1999 to 2009. PATIENTS 1203 adult living kidney donors. MEASUREMENTS Core-needle biopsy of the renal cortex obtained during surgical implantation of the kidney, and medical record data of kidney function and risk factors obtained before donation. RESULTS The prevalence of nephrosclerosis (> or =2 chronic histologic abnormalities) was 2.7% (95% CI, 1.1% to 6.7%) for patients aged 18 to 29 years, 16% (CI, 12% to 20%) for patients aged 30 to 39 years, 28% (CI, 24% to 32%) for patients aged 40 to 49 years, 44% (CI, 38% to 50%) for patients aged 50 to 59 years, 58% (CI, 47% to 67%) for patients aged 60 to 69 years, and 73% (CI, 43% to 90%) for patients aged 70 to 77 years. Adjustment for kidney function and risk factor covariates did not explain the age-related increase in the prevalence of nephrosclerosis. LIMITATION Kidney donors are selected for health and lack the spectrum or severity of renal pathologic findings in the general population. CONCLUSION Kidney function and chronic kidney disease risk factors do not explain the strong association between age and nephrosclerosis in healthy adults. PRIMARY FUNDING SOURCE National Institutes of Health, U.S. Public Health Service.

Baseline Donor‐Specific Antibody Levels and Outcomes in Positive Crossmatch Kidney Transplantation

Renal transplant candidates with donor‐specific alloantibody (DSA) have increased risk of antibody‐mediated allograft injury. The goal of this study was to correlate the risk of antibody‐mediated rejection (AMR), transplant glomerulopathy (TG) and graft survival with the baseline DSA level (prior to initiation of pretransplant conditioning). These analyses include 119 positive crossmatch (+XM) compared to 70 negative crossmatch (−XM) transplants performed between April 2000 and July 2007. Using a combination of cell‐based crossmatch tests, DSA level was stratified into very high +XM, high +XM, low +XM and −XM groups. In +XM transplants, increasing DSA level was associated with increased risk for AMR (HR = 1.76 [1.51, 2.07], p = 0.0001) but not TG (p = 0.18). We found an increased risk for both early and late allograft loss associated with very high DSA (HR = 7.71 [2.95, 20.1], p = 0.0001). Although lower DSA recipients commonly developed AMR and TG, allograft survival was similar to that of −XM patients (p = 0.31). We conclude that the baseline DSA level correlates with risk of early and late alloantibody‐mediated allograft injury. With current protocols, very high baseline DSA patients have high rates of AMR and poor long‐term allograft survival highlighting the need for improved therapy for these candidates.