Rabbit Antithymocyte Globulin Induction in Heart Transplant Recipients at High Risk for Rejection

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Figure 1.
High immunologic risk criteria. cPRA, calculated panel reactive antibodies; HLA, human leukocyte antigen.
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Figure 2.
Study participation. rATG, rabbit antithymocyte globulin.

Table 1.

Demographic and Clinical Characteristics

Variable	No-Induction Group (n=29)	rATG Induction Group (n=21)	P Value
Age, years, mean ± SD	46.7 ± 13.63	46.3 ± 17.77	0.941
Age <40 years	11 (37.9)	9 (42.9)	0.775
Female	17 (58.6)	7 (33.3)	0.093
African American	19 (65.5)	15 (71.4)	0.763
Ischemic cardiomyopathy	8 (27.6)	3 (14.3)	0.318
Pretransplant diabetes	9 (31.0)	3 (14.3)	0.201
Triglyceride level, mg/dL, mean ± SD	124.7 ± 73.32	99.5 ± 39.22	0.124
Prednisone
6 months posttransplant	25 (86.2)	19 (90.5)	0.999
12 months posttransplant	20 (69.0)	16 (76.2)	0.708
Cytomegalovirus donor seropositive/recipient seronegative	4 (13.8)	8 (38.1)	0.047
Left ventricular assist device implantation	16 (55.2)	12 (57.1)	0.889
≥4 HLA mismatches	28 (96.6)	18 (85.7)	0.296
Pretransplant donor-specific antibody	11 (37.9)	11 (52.4)	0.309
cPRA 1%-10%	3 (10.3)	0	0.254
cPRA 11%-25%	3 (10.3)	2 (9.5)	0.999
cPRA >25%	3 (10.3)	8 (38.1)	0.035
cPRA >50% within previous year	5 (17.2)	6 (28.6)	0.491
History of transplant	0	0
History of desensitization	0	1 (4.8)	0.420
Positive flow crossmatch	4 (13.8)	4 (19.0)	0.705

Note: Data are presented as n (%) unless otherwise indicated.
cPRA, calculated reactive panel antibody; HLA, human leukocyte antigen; rATG, rabbit antithymocyte globulin.

Table 2.

Drug Levels and Doses

Drug	No-Induction Group (n=29)	rATG Induction Group (n=21)	P Value
Tacrolimus level, ng/mL, mean ± SD
1 month	10.65 ± 3.090	10.14 ± 2.948	0.596
3 months	11.58 ± 4.741	11.23 ± 2.254	0.710
6 months	12.03 ± 3.505	10.81 ± 2.975	0.207
12 months	9.11 ± 3.227	8.19 ± 2.622	0.336
Mycophenolate daily dose, mg, mean ± SD
1 month	2,740.7 ± 712.1	2,952.3 ± 218.2	0.389
3 months	2,192.3 ± 1,059	2,119.0 ± 960.5	0.938
6 months	1,907.5 ± 1,042.5	1,547.6 ± 1,011.2	0.183
12 months	1,773.5 ± 1,077.3	1,261.9 ± 956.8	0.056
Prednisone daily dose, mg, mean ± SD
1 month	35.18 ± 16.95	24.04 ± 13.74	0.014
3 months	13.51 ± 8.35	12.09 ± 8.31	0.551
6 months	8.14 ± 7.89	4.78 ± 3.64	0.077
12 months	2.51 ± 2.09	3.28 ± 2.68	0.266

Table 3.

Composite Primary Outcome and Secondary Outcomes

Outcome	No-Induction Group (n=29)	rATG Induction Group (n=21)	P Value
Composite primary outcome	14 (48.3)	8 (38.1)	0.474
>2R rejection^a	3 (10.3)	2 (9.5)	0.999
Any treated rejection	9 (31.0)	3 (14.3)	0.171
Graft loss	0	0
Cardiac allograft vasculopathy^b	7 (33.3)	5 (25.0)	0.557
Secondary outcomes
Posttransplant lymphoproliferative disorder	0	0
Infusion reactions	0	0
Infections	14 (48.3)	10 (47.6)	0.963
All-cause mortality	1 (3.4)	0	0.999

↵^aRejection as defined by the International Society for Heart and Lung Transplantation.
↵^bCardiac allograft vasculopathy is a composite outcome defined angiographically or by intravascular ultrasound. Complete data were available for 21 patients in the no-induction group and 20 patients in the rATG induction group.
Note: Data are presented as n (%).
rATG, rabbit antithymocyte globulin.