Thrombocytopenia in liver transplant recipients - Predictors, impact on fungal infections, and role of endogenous thrombopoietin

Background. Thrombocytopenia is a frequent and potentially serious complica tion in liver transplant recipients. The role of endogenous thrombopoietin level in posttransplant thrombocytopenia, has not been fully defined in liv er transplant recipients. Additionally, there is accumulating evidence to s uggest that platelets play a important role in antimicrobial host defense. Methods, There were 50 consecutive Liver transplant recipients studied. Var iables predictive of thromobocytopenia, its impact on infections morbidity and outcome, and serial thrombopoietin (TPO) serum concen-; tration were as sessed. Results, The median pretransplant platelet count was 67x10(3)/cmm, After th e liver transplantation, the median nadir platelet count was 33x10(3)/cmm a nd was reached a mean of 6 days after the transplant, A lower pretransplant platelet count (r = +.068, P = .0001), lower serum albumin before the tran splants (r = +0.39, P = .014), longer operation time (r = 0.27, P = .05), h igher intraoperative packed red cells (r = 0.28, P = .049) and fresh frozen plasma transfusions (r = 0.42, P = .004), higher bilirubin at Day 7 (r = - .386, P = .005), and higher serum creatinine at Day 7 after the transplants (r = -.031, P = .025) correlated significantly with a lower nadir in plate lets after the transplant. Nadir in platelet count was significantly lower in nonsurvivors compared with survivors (16 vs, 366x10(3)/cmm, P = .0001). Forty-three percent (9 of 21) of the patients with nadir platelet counts of less than or equal to 30x10(3)/cmm had a major infection within 30 days of the transplant compared with 17% (5 of 29) with nadir platelet counts > 30 x10(3)/cmm (P = .04). Fungal infections occurred in 14% of the patients wit h nadir platelet counts of less than or equal to 30x10(3)/cmm versus 0% in those with nadir platelet counts of > 30x103/cmm (P = .06); all patients wi th fungal infections had nadir platelet counts of less than or equal to 30x 10(3)/ cmm before fungal infection, Nadir in platelet count preceded the fi rst major infection by a median of 7 days. Pretransplant TPO level did not differ between survivors (mean 103 pg/ml) or nonsurvivors (mean 144 pg/ml), After the transplantation, TPO levels increases in both groups. TPO level peaked at Day 7 and subsequently declined in survivors. Nonsurvivors had pe rsistent thrombocytopenia despite a progressive rise in TPO level; TPO leve l was significantly higher at Day 7 (P = .02), Day 9 (P = .0019), and Day 1 4 (P = .04) in nonsurvivors compared with survivors. Conclusion. Persistent thrombocytopenia portended a poor outcome in liver t ransplant recipients and was not related to low TPO levels, Thrombocytopeni a preceded infections and identified a subgroup of liver transplant patient s susceptible to early major infections; its precise role in fungal infecti ons warrants validation in larger studies.