Abstract
Background
Impact of organ quality in long-term graft function in living kidney transplantation is less well understood. Potential markers of donor organ quality in living kidney donation may include donor kidney volume and weight. There have been some studies done which correlated individually graft volume with its outcome. Trials have also explored in the fact that graft mass also influences the recipient eGFR. But no study so far has combined these two variables and correlated with the graft outcome.
Aims
To study the association between baseline graft kidney volume and weight matched with recipient body surface area and graft function by serum creatinine. Secondarily the association with proteinuria, graft survival at 1 year and episodes of acute rejection was also studied.
Method
Prospective observational single centre study conducted at our centre. Total 60 live donor renal transplants from period of October 2018 to December 2018 were assessed for the donor kidney volume and its weight and then correlated with creatinine at post-transplant day 7 and 1 year after transplant. Cadaveric, paediatric and second transplants were excluded. Whole renal parenchymal volume was obtained from the delayed phase CT data excluding the renal sinus fat using Syngo Volume Calculation. According to common procedure recommendations, kidney grafts were prepared first then weighed by the surgeon.
Results
45 were female donors and 15 were male donors. Mean donor age was 46.60 +/- 12.04 years with minimum donor age of 19 years and maximum donor age of 75 years. The donated graft GFR was 48.86 ml/min/1.73 m2 with a S.D. of 42.77 ml/min/1.73 m2. .Mean transplanted graft volume (donated kidney volume X 1.73 m2/ recipient BSA) was 137.49 mm3/1.73m2 with a S.D. of 28.34 mm3/1.73m2 (Minimum 95 mm3/1.73 m2 and maximum 227.23 mm3 /1.73 m2). Mean total kidney volumes of females was 254.45 +/- 46.57 mm3 and males was 293.37 +/- 42.99 mm3 (p value < 0.05). Donor kidney volume and donor age showed negative co-relation (r-0.25) (p-0.08.) Donor kidney volume and donor GFR showed a positive co-relation (r 0.38) and it was statistically significant p < 0.001. Graft volume and serum creatinine on post-transplant day 7 had negative co-relation (r=-0.19), not statistically significant. Graft volume had negative co-relation with creatinine at 1 year (r= -0.49), statistically significant (p < 0.01). Hence lower the graft volume, higher the creatinine. Mean transplanted graft weight was 170 grams (+/- 34 grams)- Minimum 119.5grams, maximum 204 grams. Donor kidney weight showed a positive correlation with the donor’s body surface area. No correlation with age was seen. Donor kidney weight and donor GFR showed a positive correlation (r 0.26). Graft weight and serum creatinine on post-transplant at 7 day showed negative co-relation(r=-0.25) but it was not statistically significant. Graft weight and creatinine at 1 year (r= -0.49) had negative co-relation and it was statistically significant (p < 0.01). Hence higher the transplanted graft volume and weight, better is the e-GFR at one year post-transplant. No significant association was found with proteinuria at 1 year with either graft volume or weight (p-0.07). In present study 3 patients had an acute cellular rejection. There was no statistically significant co-relation found between kidney volume and acute cellular rejection. None of the patients had an acute humoral rejection till 1 year of follow up period. None of the patients had graft loss till 1 year follow up.
Conclusion
The present study shows that during pre-operative donor evaluation, the donor kidney volume and weight estimation helps us in predicting the outcome of the renal transplant. Better kidney volumes matched to the body surface area of recipient predict better outcomes. Hence kidneys with higher graft volume and weight that is matched to recipient have better e-GFR at 1year post-transplant. This will help us in finding the suitable donors wherever feasible.
The correlation between preoperative volumetry and actual graft weight of liver according to the donor age
