Influence of splenectomy on platelet morphometry and function.

Functional and morphometric platelet abnormalities may be influenced by splenectomy and thus contribute to postoperative thrombohaemorrhagic complications, especially in patients with splenomegaly and/or platelet defects. We investigated platelet function, platelet secretion, and platelet morphometry before and one week after splenectomy in seven patients with normal platelet production and normal spleen size (Hodgkin's disease) and five patients with splenomegaly and platelet abnormalities (4 with myeloproliferative disorders and 1 with chronic myelomonocytic leukemia). Severe postoperative thrombohaemorrhagic complications occurred only in patients with myeloproliferative disorders, although platelet count and mean platelet volume increased in almost all patients after splenectomy. Four patients with myeloproliferative disorders had impaired platelet aggregation before splenectomy that improved in only one patient after surgery. Platelet buoyant density in this patient group was decreased before splenectomy and normalised thereafter. Concomitantly, intraplatelet concentrations of alpha-granular proteins increased. Before splenectomy, there was a positive correlation between platelet density and platelet volume in patients with Hodgkin's disease (r = 0.59, p less than 0.001), but not in patients with myeloproliferative disorders. There was no correlation between platelet density and platelet volume after splenectomy in either patient group. In conclusion, morphometric platelet abnormalities were found in all patients after splenectomy. In patients with myeloproliferative/myelodysplastic disorders, decreased platelet buoyant density normalised and intraplatelet concentrations of alpha-granule proteins were elevated after splenectomy. However, platelet function defects in this patient group were not corrected and may have been a major cause of thrombohaemorrhagic complications in the postoperative period.