Postsplenectomy thrombocytosis: its association with mesenteric, portal, and/or renal vein thrombosis in patients with myeloproliferative disorders.

During the past two years, postoperative thromboses of parts or all of the splanchnic venous circulation have developed in four of 30 patients with myeloproliferative disorders who have undergone splenectomy at our institution. The patients' courses were marked by platelet abnormalities, both quantitative and qualitative. In an attempt to avoid this complication, aspirin and low-dose heparin sodium have been administered and there has been no evidence of thrombosis in the four patients so managed.