Abstracts

The use of valproic acid has been associated to bleeding in some centers and reports. On the other hand, there is no consensus on if valproate should be withdrawn before major surgical procedures, such as neurosurgical operations or not. This paper reviews our experience with refractory epileptic patients who underwent neurosurgical procedures and who were under high dosage of valproate which has not been withdrawn before surgery. One hundred consecutive refractory epileptic patients (children and adults) who have been receiving at least 1500mg of valproate daily (mean = 2250mg / day) and who have been submitted to epilepsy surgery have been retrospectively reviewed. All patients have been submitted to standard preoperative coagulation tests including platelet function and have no formal abnormal findings (patients with clear preoperative coagulopathies have been excluded from this analysis). Six patients presented with extensive, clearly abnormal, bleeding during surgery; the mean transfusion volume was 3,0 liters. Only 1 patient presented with clinically significant postoperative hemathoma (epidural) that had to be evacuated. These 6 patients had more transfusions and longer hospital permanence, but no difference regarding long-term outcome. All these patients have been receiving at least 2500mg of valproate daily (mean 3000mg/day) and had platelet counts at the lower normal range. The other patients did not differ from patients not receiving valproate regarding intraoperative bleeding, hospital stay, transfusion or outcome. Although not statistically significant, patients receiving 2500mg/day or more of valproic acid and low (although within normal range) platelet counts might be in risk for intraoperative bleeding during major surgical procedures. Considering the potential risk for major neurological complications, we recommend that valproate should be withdrawn in this selected patient population.