Perioperative changes in platelet count in patients with atrial septal defect.

BACKGROUND Platelet count and function change following atrial septal defect (ASD) closure with the Amplatzer septal occluder (ASO). However, the clinical significance of these changes remains unclear. We examined changes in platelet count, mean platelet volume (MPV) before and after ASO placement and the association between platelet count, MPV and various factors. We discussed the mechanism and clinical significance of changes in platelet count and MPV. METHODS We evaluated 109 patients with ASD who underwent ASO placement and performed various analyses of platelet count and MPV. RESULTS Younger patients typically had higher platelet counts and lower MPV on admission. They also had large ASDs relative to their body constitution; therefore, larger devices were used. Rates of change in platelet count were higher in younger patients. There were no significant associations between platelet count or MPV before placement and mean pulmonary artery pressure (MPAP), and Qp/Qs, and between the number of thrombocytopenia and presence or absence of headache or residual ASD. Platelet counts decreased on an average by 21.3% for the first 3 days after ASO placement. One month after placement, platelet counts were slightly improved but remained lower than before placement. Conversely, MPV increased significantly after ASO placement and remained high one month after placement. ASO size was the most influential factor in platelet count reduction after ASD closure by ASO. CONCLUSIONS One month after ASO placement, platelet counts decreased and MPVs continued to increase, suggesting that platelet consumption and new production were still occurring one month after placement.