Developing a donation after cardiac death risk index for adult and pediatric liver transplantation

Table 1 Summary of the descriptive statistics for donor (d) and the recipient (r) that form the study donor after cardiac death cohort from which the donor after cardiac death risk index score was developed

DCD donor and recipient variables			All (n = 261)
Donor	dAge (yr)		46.1 ± 17.9
	dBMI		26 ± 4.9
	ITU Stay (d)		3.9 ± 5.8
	COD (CVA: Other: HBI: Trauma)		52.5:13.8:16.9:16.9
	dSodium (mmol/L)		144.51 ± 11.8
	dBilirubin (μmol/L)		9.81 ± 6.88
	Split/reduced (%)		2.30%
	WIT (min)		16.7 ± 9.8
	dHepT (min)		24.3 ± 10.6
	Liver Weight (g)		1518.28 ± 397.507
	CIT (min)		431 ± 118
Recipient	rAge (yr)		49.45 ± 15.36
	rGender		70.1%M/39.9%F
	rBMI		25.9 ± 4.7
	ALF (%)		1.50%
	rBilirubin (mmol/L)		89.36 ± 116.38
	rINR		1.89 ± 1.88
	MELD		14.8 ± 6.4
	Location (inpatient/home)		20.3%/79.6%
	Prior abdominal surgery (yr)		13.40%
	reTPL (yr)		5.70%
	Indication for TPL	Low	68 (26%)
		Standard	176 (67.5%)
		High	17 (6.5%)

Data presented as mean ± SD or % where appropriate. Primary indication for transplant has been divided into three risk groups of low, standard and high risk, as defined by their survival curves. BMI: Body mass index; COD: Cause of death; CVA: Cerebrovascular accident; HBI: Hypoxic brain injury; WIT: Warm ischemic time; CIT: Cold ischemic time; dHepT: Donor hepatectomy time; ALF: Acute liver failure; MELD: Model for end stage liver disease; reTPL: Retransplantation; TPL: Transplant.

Table 2 Point allocation system for the donor after cardiac death risk index score

Donor/recipient predictor variables	HR (CI)	Points
Primary indication for transplant
Low (P = 0.07)
Standard (P = 0.05)	2 (1-4.04)	2
High (P = 0.04)	2.83 (1.04-7.24)	3
reTPL (P = 0.26)	1.87 (0.63-5.58)	2
MELD > 25 (P = 0.04)	2.75 (1.04-7.24)	3
CIT > 10 h (P = 0.6)	1.37 (0.4-4.04)	1
WIT > 25 min (P = 0.4)	1.48 (0.6-3.63)	1
dHepT
40-60 min (P = 0.5)	1.36 (0.53-3.53)	1
> 60 min (P = 0.05)	4.4 (1.02-19.04)	4

Points were given to each variable in proportion to their calculated hazard ratio (HR). Primary indication for liver transplant has been divided into three risk groups of low, standard and high, as defined by their survival curves. Low DCD risk indications for transplant include autoimmune hepatitis, primary sclerosing cholangitis, primary biliary cirrhosis, non-alcoholic steatohepatitis, Hepatitis B virus and cholestatic liver disease (primary familial intrahepatic cholestasis, extrahepatic biliary atresia and Crigler Najjar). Standard risk indications were metabolic diseases that included Wilson’s, Hemochromatosis and Familial Amyloid Polyneuropathy. High risk indications for DCD transplant were alcohol related liver disease; HCV: Hepatitis C virus, cryptogenic and Budd Chiari. reTPL: Retransplantation; MELD: Model for end stage liver disease; CIT: Cold ischemic time; WIT: Warm ischemic time; dHepT: Donor hepatectomy time; HCC: Hepatocellular carcinoma.

Table 3 Internal validation of the donor after cardiac death risk index in predicting donor after cardiac death graft survival

DCD Graft Survival (mo)	DCD-RI class
	DCD-RI ≤ 1, low (n = 10/27%)	DCD-RI 2-4, standard (n = 8/21.6%)	DCD-RI ≥ 5, high (n = 19/51.4%)
3
Actual	100	92.6	75
Predicted	96 (100-83.8)	90 (100-76.8)	80 (96.2-63.8)
6
Actual	100	85.2	75
Predicted	95 (100-83.7)	90 (100-83.8)	75 (91.2-58.8)
12
Actual	100	77.8	75
Predicted	93 (100-76.8)	87 (100-70.8)	40 (56.2-23.8)
60
Actual	100	63	50
Predicted	86 (100-83.8)	78 (94.2-61.8)	34 (50.2-17.8)

The DCD-RI was calculated for an earlier DCD transplant cohort (2001 - 2004). The table summarizes actual and predicted graft survival as calculated with the DCD-RI. The DCD-RI predicted survival showed good correlation with actual graft survival, as actual graft survival fell within the confidence interval of DCD-RI predicted graft survival. DCD: Donor after cardiac death; DCD-RI: Donor after cardiac death risk index.