Renal transplants from older deceased donors: Is pre-implantation biopsy useful? A monocentric observational clinical study

Table 1 Histologic score in use for kidney allocation to single kidney transplant or dual kidney transplants of “high-risk” donors

Glomerular global sclerosis	0 = no glomeruli globally sclerosed
	1 = less than 20%
	2 = 20%-50%
	3 = > 50%
Arteries/arterioles wall thickness1	0 = normal appearance
	1 = less than lumen diameter
	2 = equal/slightly higher than lumen diameter
	3 = higher than lumen diameter/severe lumen reduction
Tubular atrophy	0 = absent
	1 = less than 20% tubuli affected
	2 = 20%-50%
	3 = > 50%
Interstitial fibrosis	0 = absent
	1 = less than 20% parenchymal tissue substituted
	2 = 20%-50% tissue
	3 = > 50% tissue

¹The most severe lesion determines the score. The final score is the sum of 4 individual scores: With final score up to 4 (included) organs are allocated to solitary kidney transplantation; from 5 to 7 organs are allocated to dual kidney transplantation; higher than 7 organs are discarded.

Table 2 Baseline characteristics of donors and recipients in the 3 transplant categories

Transplant category1	SKT(1-4)	SKT(> 4)	DKT
n	102	30	53
Donors, M/F	54/48	16/14	29/24
Donor age, yr (mean, SD)	68.9 ± 5.7	66.9 ± 6.7	75.3 ± 5.0b
Score of transplanted graft, median (IQR)	3 (3-4)d	5 (5-6)a	5 (4-5)
Donor comorbidities
Donor age > 70 yr, n (%)	47 (46)	8 (27)	47 (89)b
Arterial hypertension	40 (39)	21 (70)	34 (64)
Diabetes	9 (9)	6 (20)	7 (13)
Cerebrovascular cause of death	33 (32)	17 (57)	29 (55)
KDPI1	89.4 ± 8.0	89.9 ± 9.2	96.9 ± 3.4b
KDRI1	1.65 ± 0.27	1.7 ± 0.33	2.02 ± 0.31b
Recipients, M/F	68/34	20/10	37/16
Recipient age (mean ± SD, yr)	61.0 ± 7.2	60.2 ± 6.0	67.3 ± 4.6b
Years on dialysis, median (IQR)	3.5 (0.1-13.5)	3.4 (0.8-9.5)	2.1 (0.3-8.5)b
Dialysis mode, n (%)
Hemodialysis	84 (82)	25 (83)	40 (75)
Peritoneal dialysis	16 (16)	5 (17)	12 (23)
Pre-emptive	2 (2)	0	1 (2)
Renal disease n (%)1
GN/systemic	35 (34)	10 (34)	19 (36)
ADPKD	24 (23)	4 (13)	6 (11)
Vascular/hypertension	10 (10)	3 (10)	3 (6)
Diabetes	11 (11)	4 (13)	7 (13)
Other	14 (14)	6 (20)	12 (23)
Unknown	8 (8)	3 (10)	6 (11)
1st-2nd-3rd Tx	95-6-1	28-2-0	51-2-0
HLA-MM (median, IQR)	4 (3-5)	4 (3-5)	4 (4-5)
CITa (mean ± SD, h)	15.0 ± 3.6	15.9 ± 4.2	16.1 ± 3.1

¹SKT_(1-4), solitary kidney transplant, histologic score 1 to 4; SKT_{(> 4)}: Solitary kidney transplant, histological score 5 or higher; DKT: Dual kidney transplant, histological score 5 to 7; KDPI and KDRI: Kidney Donor Profile Index and Kidney Donor Risk Index; GN/systemic: Glomerulonephritis or systemic immunological disorder; CIT: Cold ischemia time.

^bP < 0.01 vs SKT (both categories);

^dP < 0.001 vs SKT_{(> 4)} and DKT;

^aP < 0.039 vs DKT.

Table 3 Summary of main post-transplant characteristics and events in the 3 transplant categories

Transplant category1	SKT(1-4)	SKT(> 4)	DKT
n	102	30	53
Initial immunosuppression, n (%)
rATG	95 (93)	25 (83)	53 (100)
Basilix imab	8 (8)	3 (10)	0
Cyclosporin	91 (89)	25 (83)	50 (94)
Tacrolimus	9 (9)	2 (7)	3 (6)
Mycophenolate	91 (89)	27 (90)	50 (94)
Everolimus	9 (9)	4 (13)	3 (6)
Sirolimus	1 (1)	1 (3)	0
Belatacept	2 (2)	1 (3)	0
Steroids	84 (82)	28 (93)	50 (94)
Tx duration2, yr (median, IQR)	4.1 (1.6-7.4)	7.0 (2.6-9.9)	2.7 (1.4-4.8)a
Total follow-up, pt-years	467.8	180.5	161.7
DGF3, %	42.1	56.6c	24.5
EGL3, n (%)
All	8 (7.8)	1 (3.3)	2 (3.8)
PNF3	4 (3.9)	1 (3.3)	0
Surgical	4 (3.9)	0	2 (3.8)
BPAR3, n (%)	10 (9.8)	3 (10.0)	3 (5.6)
Graft failure4, n (n/100 pt-yr)	10 (2.1)	6 (3.3)	3 (1.8)
Pt-death, n (n/100 pt-yr)	16 (3.4)	4 (2.0)	6 (3.5)

¹SKT_(1-4), solitary kidney transplant, histologic score 1 to 4; SKT_{(> 4)}: Solitary kidney transplant, histological score 5 or higher; DKT: Dual kidney transplant, histological score 5 to 7;

²Right-censored at 6 (DKT) and 10 (SKT) years;

³DGF: Need of dialysis in the first post-transplant week; EGL: Graft loss within 3 mo; PNF: Primary non-function from unknown cause; BPAR: Biopsy-proven acute rejection;

⁴Censored for death with functioning graft;

^aP < 0.03 vs SKT (both categories);

^cP < 0.05 vs DKT.

Table 4 Mean ± SD of plasma creatinine and GFR (Cockcroft-Gault formula in donors or 24 h-creatinine clearance in recipients) in donors (D) and recipients (R; at 3 and 12 mo after transplantation) in each transplant category

Transplant category1	SKT(1-4)	SKT(> 4)	DKT
D-Pcr, mg/dL	0.88 ± 0.31	0.92 ± 0.28	0.81 ± 0.23
D-eGFR	83.9 ± 27.7	87.1 ± 26.0	79.1 ± 21.8
n	102	30	53
R-Pcr 3 mo	1.92 ± 0.98	2.12 ± 1.12	1.56 ± 0.75a
R-CCr 3 mo	45.0 ± 19.3	43.4 ± 21.8	49.6 ± 19.6
n	94	28	49
R-Pcr 12 mo	1.71 ± 0.69	1.69 ± 0.63	1.46 ± 0.57c
R-CCr 12 mo	49.6 ± 18.5	52.6 ± 18.8	55.4 ± 20.4
n	83	25	45

¹SKT_(1-4): Solitary kidney transplant, histologic score 1 to 4; SKT_{(> 4)}: Solitary kidney transplant, histological score 5 or higher; DKT: Dual kidney transplant, histological score 5 to 7;

^aP < 0.02 vs SKT_(1-4) and SKT_{(> 4)};

^cP < 0.04 SKT_(1-4). Pcr: Plasma creatinine; D: Donors; R: Recipients.

Table 5 Restricted number (95%CI) of functioning graft years at 1, 3 and 6 years post-transplantation, and projected number of total dialysis-free life years in recipients for every 100 transplants or 100 donors in each transplant category. Differences indicated in bold indicate a statistically significant difference (P < 0.05)

		1 yr	3 yr	6 yr
RNFGY (× 100 Tx)	SKT(1-4)	93.3 (86.9-99.7)	261.0 (253.3-268.7)	499.6 (490.5-508.7)
	SKT(> 4)	93.8 (85.2-102.4)	279.5 (266.9-292.1)	499.9 (482.5-517.2)
	DKT	97.7 (91.4-104.1)	275.0 (264.1-285.8)	507.3 (496.0-524.3)
TDFLY (× 100 donors)	SKT(1-4)	149.3 (139.1-159.6)	417.6 (405.4-429.9)	799.3 (784.7-813.9)
	SKT(> 4)	150.1 (136.2-163.9)	447.2 (427.1-467.4)	799.8 (772.1-827.6)
	DKT	97.7 (91.4-104.1)	275.0 (264.1-285.8)	507.3 (496.0-524.3)
Vs DKT, difference
	SKT(1-4)	51.6 (35.0-68.2)	142.7 (119.5-165.8)	292.0 (260.4-317.9)
	SKT(> 4)	52.3 (32.2-72.5)	172.3 (141.2-203.3)	292.5 (247.8-331.6)

RNFGY: Restricted number (95%CI) of functioning graft years; TDFLY: Total dialysis-free life years; DKT: Dual kidney transplant.