Dual Kidney Transplantation Involving Organs From Expanded Criteria Donors: A Review of Our Series and an Update on Current Indications J. Medina-Poloa,*, M. Pamplona-Casamayora, N. Miranda-Utreraa, E. González-Monteb, J.B. Passas-Martíneza, and A. Andrés Belmonteb a Department of Urology, Hospital Universitario 12 de Octubre, Madrid, Spain; bDepartment of Nephrology and Transplant Coordination, Hospital Universitario 12 de Octubre, Madrid, Spain
ABSTRACT Background. Our purpose was to review our kidney transplantation program based on the use of expanded criteria donors, and to determine current indications for dual kidney transplantation (DKT). In 1996, a program was initiated to transplant kidneys from donors of over 60 years performing single or dual transplantation. Methods. In 1996, a program was initiated to transplant kidneys from donors of over 60 years performing single or dual transplantation. DKT were performed with donors >75 and donors between 60 and 74 years of age and glomerulosclerosis of >15%. The kidneys of donors between 60 and 74 years of age and with glomerulosclerosis of 15%, taking into account donor and recipient characteristics. Results. From 1996 to 2004, 222 SKTs and 88 DKTs were performed. Graft survival after 1 and 4 years was, respectively, 91% and 78% for SKT and 95% and 79% for DKT. In 2005, we started to perform SKT despite glomerulosclerosis being >15%, taking into account donor and recipient characteristics. From 2005 to 2011, 328 SKT and 32 DKT were performed. During this period most kidneys used for DKT were from female donors >75 years old, weighing 1 mg/dL and glomerulosclerosis of >15%. The recipients for DKT were mostly male, 75 kg. Conclusion. DKT from expanded criteria donors shows good outcomes. However, in many cases SKT may fulfill the need of the recipient. The archetype for DKT is an older female weighing 60 years old, with 21% >70 [3]. In 2002, the Organ Procurement and Transplantation Network/United Network for Organ Sharing adopted a new ECD allocation policy, establishing a definition of ECD based on donors >60 years of age, donors aged between 50 and 59 with a risk factor, or those 60 years of age into elderly recipients, after assessing their functional and anatomical viability. SKT or DKT is performed, depending on donor age and the percentage of glomerulosclerosis. Kidneys underwent macroscopic inspection in which the anatomy of the artery and renal veins are evaluated, as well as the macroscopic appearance of the parenchyma after perfusion with preservation solution. A renal biopsy was obtained and processed using freezing techniques, and the percentage of glomerulosclerosis assessed. When the kidney biopsy shows >50% glomerulosclerosis, the kidney was discarded. From 1996 to 2004, DKT were performed with donors >75 and donors between 60 and 74 years of age and a glomerulosclerosis of >15%. The kidneys of donors between 60 and 74 and with glomerulosclerosis 15%. The updated protocol also takes into account the previous history of the donor, and kidney recipient characteristics such as age, weight, sex, and comorbidities. These parameters were used to adjust the nephron mass, which hypothetically would be needed to cover the majority of the life expectancy of the recipient. In the case of DKT, each kidney was normally implanted extraperitoneally in each iliac fossae, using an end-to-side vascular anastomosis to the iliac vessels. Urinary tract reconstruction was performed by bilateral transvesical ureterocystostomy. Our immunosuppression regimen usually consisted of corticosteroids, cyclosporine or tacrolimus, and mycophenolate mofetil. The following variables were assessed: Clinical characteristics of donors and recipients, graft and recipient survival, and serum creatinine at followup after 1 and 4 years. Donor and recipient characteristics were described using mean values standard deviation or frequencies. For statistical analysis, the association between variables was estimated by the c2 test for categorical variables and by the Student t test for continuous variables. P < .05 were regarded as significant. Data were analyzed using the Statistical Package for Social Sciences version 17.0 (SPSS, Inc., Chicago, IL).
RESULTS
From December 1996 to 2004, 310 transplants using ECD were performed at our centerd222 SKTs and 88 DKTs. Average donor age was 68 5 years for SKT and 75 5 years for DKT. Recipient age was 64 7 years for SKT and 62 6 years for DKT. Patient survival on follow-up after 1 and 4 years was 94% and 87%, respectively, for SKT, and 96.5% and 88% for DKT. Graft survival after 1 and 4 years was 91%
3413
and 78%, respectively, for SKT, and 95% and 79% for DKT. Serum creatinine on follow-up after 1 year was 1.8 0.8 mg/ dL for SKT and 1.6 0.6 mg/dL for DKT (Table 1). Between 2005 and 2011, 360 transplants using ECD were performed at our center, with 328 SKT and 32 DKT. The number of DKTs has fallen over the years: Analysis of the percentage of DKT carried out involving ECDs shows that 28.4% were performed between 1996 and 2004, and only 8.9% between 2005 and 2011. In the final years included in our study, there were only 2 cases of DKT in 2009, and 1 in 2010 and 2011 each. Figure 1 shows the evolution in the number of DKTs performed at our center and in our country [3]. Most kidneys used for DKT were from female donors >75 years of age, whose weight was 15%. Recipients for DKT were male and 75 kg. The characteristics of donors and recipients for DKT performed at our center between 2007 and 2011 are summarized in Table 2. DISCUSSION
Over the years the pool of ECD has increased, and the number of patients waiting for kidney transplants has grown. Although kidneys from older donors have shown lower survival rates, these grafts are usually transplanted into older recipients, most of whom died with a functioning graft [1]. Furthermore, kidney transplantation is associated in all age ranges with a higher quality of life and better survival rates than dialysis. Annual mortality among patients on dialysis is 23%, and the risk of dying on dialysis is proportional to age [8,9]. Recipients of kidneys from ECD are estimated to live 5 years longer than dialysis patients awaiting transplantation, and both DKT and SKT entail lower costs than dialysis [10]. In concordance with previous data, our series shows that DKT with elderly donor kidneys offers an acceptable option for kidney transplantation, despite the greater complexity of surgery [6,9]. Several transplant groups have recently reported long-term outcomes with DKT [11], although kidneys from donors >60 years of age are more often discarded, the main causes for the discarding of these grafts being arteriosclerosis or microscopic kidney abnormalities which may make transplantation impossible, and a lack of elderly recipients on waiting lists [5]. The general discard rate for kidneys from donors of >60 years of age is approximately 50% [1], and at our center the percentage of kidneys from ECD discarded is 46% [5]. Although DKT does offer acceptable outcomes, the main question to answer is whether grafts from ECD should be used for DKT or SKT, and how many patients might as a consequence be able to discontinue dialysis [7]. Grafts from ECD usually have a low nephron mass, which is a risk factor for the development of glomerular hyperfiltration and hypertension, which in turn lead to progressive glomerulosclerosis. Moreover, cold ischemia time and immunosuppressive therapy may also exert deleterious effects [12].
3414
MEDINA-POLO, PAMPLONA-CASAMAYOR, MIRANDA-UTRERA ET AL Table 1. Simple Kidney Transplantation (SKT) and Dual Kidney Transplantation (DKT) Between 1996 and 2004
Donor age (y) Recipient age (y) Graft survival (y) 1 4 Recipient survival (y) 1 4 Follow-up serum creatinine (mg/dL) 1 Year 4 Year
SKT (n ¼ 222), Mean SD
DKT (n ¼ 88), Mean SD
P
68.4 5.35 (60e74) 64.3 7.22 (28e80)
75.5 5.81 (61e89) 62.0 6.07 (42e73)
20% Recipient Age 75 years of age, with a body weight of 15% on kidney biopsy. All of these factors are associated with reduced glomerular mass. Most of the recipients for DKT, on the other hand, are overweight males,
ABSTRACT Background. Our purpose was to review our kidney transplantation program based on the use of expanded criteria donors, and to determine current indications for dual kidney transplantation (DKT). In 1996, a program was initiated to transplant kidneys from donors of over 60 years performing single or dual transplantation. Methods. In 1996, a program was initiated to transplant kidneys from donors of over 60 years performing single or dual transplantation. DKT were performed with donors >75 and donors between 60 and 74 years of age and glomerulosclerosis of >15%. The kidneys of donors between 60 and 74 years of age and with glomerulosclerosis of 15%, taking into account donor and recipient characteristics. Results. From 1996 to 2004, 222 SKTs and 88 DKTs were performed. Graft survival after 1 and 4 years was, respectively, 91% and 78% for SKT and 95% and 79% for DKT. In 2005, we started to perform SKT despite glomerulosclerosis being >15%, taking into account donor and recipient characteristics. From 2005 to 2011, 328 SKT and 32 DKT were performed. During this period most kidneys used for DKT were from female donors >75 years old, weighing 1 mg/dL and glomerulosclerosis of >15%. The recipients for DKT were mostly male, 75 kg. Conclusion. DKT from expanded criteria donors shows good outcomes. However, in many cases SKT may fulfill the need of the recipient. The archetype for DKT is an older female weighing 60 years old, with 21% >70 [3]. In 2002, the Organ Procurement and Transplantation Network/United Network for Organ Sharing adopted a new ECD allocation policy, establishing a definition of ECD based on donors >60 years of age, donors aged between 50 and 59 with a risk factor, or those 60 years of age into elderly recipients, after assessing their functional and anatomical viability. SKT or DKT is performed, depending on donor age and the percentage of glomerulosclerosis. Kidneys underwent macroscopic inspection in which the anatomy of the artery and renal veins are evaluated, as well as the macroscopic appearance of the parenchyma after perfusion with preservation solution. A renal biopsy was obtained and processed using freezing techniques, and the percentage of glomerulosclerosis assessed. When the kidney biopsy shows >50% glomerulosclerosis, the kidney was discarded. From 1996 to 2004, DKT were performed with donors >75 and donors between 60 and 74 years of age and a glomerulosclerosis of >15%. The kidneys of donors between 60 and 74 and with glomerulosclerosis 15%. The updated protocol also takes into account the previous history of the donor, and kidney recipient characteristics such as age, weight, sex, and comorbidities. These parameters were used to adjust the nephron mass, which hypothetically would be needed to cover the majority of the life expectancy of the recipient. In the case of DKT, each kidney was normally implanted extraperitoneally in each iliac fossae, using an end-to-side vascular anastomosis to the iliac vessels. Urinary tract reconstruction was performed by bilateral transvesical ureterocystostomy. Our immunosuppression regimen usually consisted of corticosteroids, cyclosporine or tacrolimus, and mycophenolate mofetil. The following variables were assessed: Clinical characteristics of donors and recipients, graft and recipient survival, and serum creatinine at followup after 1 and 4 years. Donor and recipient characteristics were described using mean values standard deviation or frequencies. For statistical analysis, the association between variables was estimated by the c2 test for categorical variables and by the Student t test for continuous variables. P < .05 were regarded as significant. Data were analyzed using the Statistical Package for Social Sciences version 17.0 (SPSS, Inc., Chicago, IL).
RESULTS
From December 1996 to 2004, 310 transplants using ECD were performed at our centerd222 SKTs and 88 DKTs. Average donor age was 68 5 years for SKT and 75 5 years for DKT. Recipient age was 64 7 years for SKT and 62 6 years for DKT. Patient survival on follow-up after 1 and 4 years was 94% and 87%, respectively, for SKT, and 96.5% and 88% for DKT. Graft survival after 1 and 4 years was 91%
3413
and 78%, respectively, for SKT, and 95% and 79% for DKT. Serum creatinine on follow-up after 1 year was 1.8 0.8 mg/ dL for SKT and 1.6 0.6 mg/dL for DKT (Table 1). Between 2005 and 2011, 360 transplants using ECD were performed at our center, with 328 SKT and 32 DKT. The number of DKTs has fallen over the years: Analysis of the percentage of DKT carried out involving ECDs shows that 28.4% were performed between 1996 and 2004, and only 8.9% between 2005 and 2011. In the final years included in our study, there were only 2 cases of DKT in 2009, and 1 in 2010 and 2011 each. Figure 1 shows the evolution in the number of DKTs performed at our center and in our country [3]. Most kidneys used for DKT were from female donors >75 years of age, whose weight was 15%. Recipients for DKT were male and 75 kg. The characteristics of donors and recipients for DKT performed at our center between 2007 and 2011 are summarized in Table 2. DISCUSSION
Over the years the pool of ECD has increased, and the number of patients waiting for kidney transplants has grown. Although kidneys from older donors have shown lower survival rates, these grafts are usually transplanted into older recipients, most of whom died with a functioning graft [1]. Furthermore, kidney transplantation is associated in all age ranges with a higher quality of life and better survival rates than dialysis. Annual mortality among patients on dialysis is 23%, and the risk of dying on dialysis is proportional to age [8,9]. Recipients of kidneys from ECD are estimated to live 5 years longer than dialysis patients awaiting transplantation, and both DKT and SKT entail lower costs than dialysis [10]. In concordance with previous data, our series shows that DKT with elderly donor kidneys offers an acceptable option for kidney transplantation, despite the greater complexity of surgery [6,9]. Several transplant groups have recently reported long-term outcomes with DKT [11], although kidneys from donors >60 years of age are more often discarded, the main causes for the discarding of these grafts being arteriosclerosis or microscopic kidney abnormalities which may make transplantation impossible, and a lack of elderly recipients on waiting lists [5]. The general discard rate for kidneys from donors of >60 years of age is approximately 50% [1], and at our center the percentage of kidneys from ECD discarded is 46% [5]. Although DKT does offer acceptable outcomes, the main question to answer is whether grafts from ECD should be used for DKT or SKT, and how many patients might as a consequence be able to discontinue dialysis [7]. Grafts from ECD usually have a low nephron mass, which is a risk factor for the development of glomerular hyperfiltration and hypertension, which in turn lead to progressive glomerulosclerosis. Moreover, cold ischemia time and immunosuppressive therapy may also exert deleterious effects [12].
3414
MEDINA-POLO, PAMPLONA-CASAMAYOR, MIRANDA-UTRERA ET AL Table 1. Simple Kidney Transplantation (SKT) and Dual Kidney Transplantation (DKT) Between 1996 and 2004
Donor age (y) Recipient age (y) Graft survival (y) 1 4 Recipient survival (y) 1 4 Follow-up serum creatinine (mg/dL) 1 Year 4 Year
SKT (n ¼ 222), Mean SD
DKT (n ¼ 88), Mean SD
P
68.4 5.35 (60e74) 64.3 7.22 (28e80)
75.5 5.81 (61e89) 62.0 6.07 (42e73)
20% Recipient Age 75 years of age, with a body weight of 15% on kidney biopsy. All of these factors are associated with reduced glomerular mass. Most of the recipients for DKT, on the other hand, are overweight males,
