The Effect of Kidney Size on Cadaveric Renal Allograft Outcome1

The effect of nephronic mass reduction of kidney transplants has not been analyzed specifically in a large cohort. Transplant injuries in cadaver kidney graft may have led to an underestimation of the magnitude of this factor. The aim of this study was to analyze the consequences of kidney mass reduction on transplantation outcome. The weights of 1142 kidney grafts were collected prospectively immediately before grafting. Donors and recipients <15 yr of age, simultaneous kidney/pancreas grafts, and technical failures before day 7 were excluded from the analysis. The analysis was performed on Cockroft-calculated creatinine clearance and proteinuria in 964 patients for whom all of the necessary information was available. This study reports that the smallest kidneys transplanted into the largest recipients (donor kidney weight/recipient body weight [DKW/RBW] <2 g/kg, n ‫؍‬ 88) increased their clearance by 2.38 ml/min every month for 6 mo (P < 0.0001) and by 0.27 ml/min thereafter (P < 0.0001). Conversely, creatinine clearance did not change for the largest kidneys transplanted into the smallest recipients (DKW/RBW ratios >4 g/kg). Next, using a Cox model analysis, it was shown that the risk of having a proteinuria >0.5 g/kg was significantly increased for the low DKW/RBW ratios <2 g/kg with 50% of patients having a proteinuria, compared with DKW/RBW ratios >4 g/kg (P < 0.001). In cadaver transplant recipients, graft mass has a rapid impact on graft filtration rate and proteinuria. Avoiding major kidney/recipient inadequacy should have a significant influence on long-term transplant function.

Section: Discussionmentioning

confidence: 99%

Impact of Graft Mass on the Clinical Outcome of Kidney Transplants

Giral¹,

Nguyen²,

Karam³

et al. 2005

“…There were 8 single-center studies, (10 -17) and it is likely that many of these single-center studies lacked adequate statistical power to test the hypothesis. Indeed, 4 studies included fewer than 200 patients (10,14,15,17). Many of the studies failed to use a multivariate analysis to eliminate possible confounding from the effects of other variables (Table 2).…”

Section: Discussionmentioning

confidence: 99%

“…Some investigators have reported reduced graft survival in situations in which the size of the donor kidney would be expected to be reduced in proportion to the size of the recipient (10,11). Other single-center studies found no effect of donor-recipient size mismatching on graft survival (12)(13)(14)(15)(16)(17). However, many of these studies may have lacked adequate statistical power to test the hypothesis rigorously.…”

mentioning

confidence: 99%

Inadequate Donor Size in Cadaver Kidney Transplantation

Kasiske¹,

Snyder²,

Gilbertson³

2002

118

Abstract. There have been conflicting reports that kidneys from small donors may be at increased risk for late graft failure if they are transplanted into large recipients. Data from the United States Renal Data System was used to study all first cadaver kidney transplantations performed during the years 1994 to 1999. Donor and recipient body surface area (BSA) combinations were included along with other patient and transplant characteristics in a Poisson analysis of factors associated with early (in the first 4 mo) and late (Ն4 mo) graft failure. The numbers of large (BSA Ͼ2.2 m 2 ) and medium size (BSA 1.6 to 2.2 m 2 ) recipients that received kidneys from small (BSA Ͻ1.6 m 2 ) donors are less than expected ( 2 ϭ 118.09; P Ͻ 0.0001), suggesting that transplant centers may be refusing some kidneys on the basis of donor-recipient size differences. Large recipients who received kidneys from small donors made up 1.5% of the population and had a 43% (95% CI, 17 to 75%; P ϭ 0.0004) increased risk of late graft failure compared with medium-size recipients who received kidneys from mediumsize donors (53.4% of the population). Medium-size recipients who received kidneys from small donors made up 12.0% of the population and had a 16% (95% CI, 6 to 26%; P ϭ 0.0012) increased risk of late graft failure. Disparities in recipient and donor size had similar adverse affects on mortality. Effects of recipient obesity (body mass index) and donor gender on late graft survival were no longer statistically significant after the effects of donor and recipient body size were taken into account. In conclusion, the relative size of the donor and recipient should possibly be taken into account when choosing kidneys for transplantation.

“…7,16 -19 The effect of kidney graft size and recipient weight (Rw) 20,21 has also been studied; however, the direct impact of matching the Kw itself (which correlates with both glomerular volume and nephron number) 15 to the Rw has been studied only in relatively small cohorts of Ͻ300 patients and only in living donors, 22,23 where the graft does not incur the same accumulating injuries as those from deceased donors.…”

mentioning

confidence: 99%

Kidney and Recipient Weight Incompatibility Reduces Long-Term Graft Survival

Giral¹,

Foucher²,

Karam³

et al. 2010

116

102

Long-term function of kidney allografts depends on multiple variables, one of which may be the compatibility in size between the graft and the recipient. Here, we assessed the long-term consequences of the ratio of the weight of the kidney to the weight of the recipient (KwRw ratio) in a multicenter cohort of 1189 patients who received a transplant between 1995 and 2006. The graft filtration rate increased by a mean of 5.74 ml/min between the third and sixth posttransplantation months among patients with a low KwRw ratio (Ͻ2.3 g/kg; P Ͻ 0.0001). In this low KwRw ratio group, the graft filtration rate remained stable between 6 months and 7 years but then decreased at a mean rate of 3.17 ml/min per yr (P Ͻ 0.0001). In addition, low KwRw ratios conferred greater risk for proteinuria, more antihypertensive drugs, and segmental or global glomerulosclerosis. Moreover, a KwRw ratio Ͻ2.3 g/kg associated with a 55% increased risk for transplant failure by 2 years of follow-up. In conclusion, incompatibility between graft and recipient weight is an independent predictor of long-term graft survival, suggesting that avoiding kidney and recipient weight incompatibility may improve late clinical outcome after kidney transplantation.