The prevalence, natural history, and implications of reactive
thrombocytosis after
liver transplantation (LT) are unknown. Prospectively collected data from July 2000 to February 2006 were analyzed. Post-LT
thrombocytosis was defined as a platelet count of > 450 x 10(3)/microL lasting for >7 days and starting within 8 weeks of
transplantation. In patients who survived >8 weeks, graft and patient outcomes were compared with
liver transplant recipients who survived >8 weeks and did not develop any
thrombocytosis. Post-LT
thrombocytosis was seen in 92 (14.7%) of 627 patients. The median onset was on day 13 (range, days 1-44) and the peak platelet count was seen on day 17 (range, days 3-110). The median duration of
thrombocytosis was 25 days (range, 7-1,253 days), with a median peak platelet count of 625 x 10/microL (range, 472-1,381 x 10/microL). Seronegative
fulminant hepatic failure was the indication for
transplantation in 18% of patients with post-LT
thrombocytosis compared with 3% of controls (P < 0.001). There was a lower proportion of patients transplanted for
hepatitis C-related
cirrhosis in the
thrombocytosis group (10% vs. 18%, P = 0.04). The occurrence of hepatic arterial
thrombosis was similar in the 2 groups (5% vs. 4%, P = NS). None of the 4 patients with platelet count higher than 1,000 x 10/microL developed thrombotic complications. Post-LT
thrombocytosis is more often associated with seronegative
fulminant hepatic failure, and there is a negative association with
hepatitis C-related
cirrhosis. Post-LT
thrombocytosis does not increase the risk of hepatic artery
thrombosis, and patients without thrombotic complications should not be treated.