Thrombocytopenia following liver transplantation

Background/Aims: Thrombocytopenia after orthotopic liver transplantation is a recognized early post-operative complication, the etiology and the outcomes of this phenomenon are, however, still vague. The aims of this study were to identify contributing factors to thrombocytopenia and to ascertain any correlation with early rejection and survival. Methods: This study includes 541 orthotopic liver transplantations (541 grafts in 494 patients), that took place in University of Miami, during the 3-year period June 1994-Sep 1997. Tacrolimus and steroids were used as baseline immunosuppressive therapy. Donor bone marrow cells (DBMC) were infused in 264 of the patients, were not available in 275 of them (controls) and the rest two received donor peripheral blood cells (living related donors). The pre-transplant and the lowest platelet count (nadir) during the first two weeks and during the third and the fourth post-transplant weeks were used for analysis. The cross match, the recipient and donor CMV serology and the early rejection episodes (1 st post-transplant month) were factors that were considered for analysis (t-test for independent samples and multiple regression analysis). Short (< 1 month) and long term survival were analyzed (Cox Regression analysis) to identify any correlation with the nadir platelet count. Results. In 90.8 % of the patients there was a 56.5 % fall of the platelets. The 4 th post-transplant day was the mean day of the nadir platelet count. The mean pre-operative platelet count fell from 100,640 / mm 3 to a mean nadir of 44,660 / mm 3, in the total group of the patients, during the first two post-transplant weeks and rose to 145,430 / mm 3 and 197,780 / mm 3 in the third and fourth post-operative week, respectively. There was no statistically significant difference in the percentage fall of the platelets between the group of patients that received DBMC infusion versus control group. The recipient CMV status, the cross match and the pre-operative platelet count were independent predictive factors of the nadir platelet count (r = 0.16, r = 0.13 and r = 0.49, respectively). Also the cross match and the pre-operative platelet count were found to be correlated, as independent factors, with the percentage fall of the platelets (r = -0.13 and r = 0.31, respectively). The nadir platelet count and the percentage of their fall were found to be significantly correlated with early rejection (p <0.01 and p < 0.05, respectively). Both the nadir platelet count and the percentage of their fall were found to be independent predictive factors of short and long-term survival (p < 0.001 and p < 0.05, respectively), while the pre-operative platelet count was not correlated with the survival. Conclusions: Thrombocytopenia in the immediate post-transplant period is correlated with early rejection and survival and it is affected by a positive cross match, the positive recipient CMV serology, and the low pre-operative platelet count, which is consistent with advanced stage liver disease. The rise of the mean platelet count in the third and fourth post-operative week reflects a proper function of the graft.