ABSENCE OF BLEEDING COMPLICATIONS IN PATIENTS UNDERGOING CORTICAL SURGERY WHILE RECEIVING VALPROATE TREATMENT

Valproate (VPA) is associated with a variety of idiosyncratic hematolo gical effects including thrombocytopenia, inhibition of platelet aggre gation, and fibrinogen depletion. This has led some investigators to r ecommend discontinuation of VPA therapy prior to elective surgical pro cedures. However, administration of VPA therapy is not altered prior t o surgery at the authors' center and no VPA-associated bleeding compli cations have been observed. Therefore, a retrospective chart review wa s conducted to verify the clinical observations in patients who had un dergone cortical resection while receiving antiepileptic drugs (AEDs). Baseline, surgical, and postoperative laboratory data were available for a total of 313 patients, 111 of whom were receiving VPA and 202 of whom were receiving AEDs without VPA (control patients). Eighty-seven percent of the patients receiving VPA were also being treated with at least one other AED. The control group was approx imately equally div ided between monotherapy (55%) and polytherapy (45%) treatments. Plate let counts were significantly lower in the control polytherapy (284 +/ - 74 X 10(9)/L) and both VPA groups (279 +/- 113 X 10(9)/L) as compare d with the control monotherapy group (314 +/- 85 X 10(9)/L). Baseline fibrinogen levels were significantly lower in the VPA than in the cont rol groups (223 +/- 91 g/dl vs. 278 +/- 95 g/dl). Both pre- and postop eratively, the VPA group had lower red blood cells counts, hematocrit, and hemoglobin levels. There was no significant difference between gr oups in estimated blood loss during surgery or qualitative wound disch arge postsurgery. There was only one case of a bleeding complication, which occurred 14 days postoperatively in a patient receiving carbamaz epine monotherapy. The results of this study confirm the clinical obse rvations of an absence of bleeding complications in patients receiving VPA therapy at the time of surgery, despite differences in laboratory parameters.