[Two Cases of Convulsive Seizures after Cardiac Surgery Suspiciously Caused by Tranexamic Acid Administration in Patients on Chronic Hemodialysis].

Tranexamic acid (TA), an antifibrinolytic agent, is commonly used in cardiac surgery with cardiopulmo- nary bypass to reduce bleeding. We report two cases of convulsive seizures after cardiac surgery with chronic kidney disease on hemodialysis. The two patients underwent aortic valve replacement, one for aortic valve regurgitation and another for aortic valve stenosis, with cardiopulmonary bypass uneventfully. A total dose of 8 g of TA was administered intravenously; 4 g during and 4 g after cardiopulmonary bypass. Both patients developed two episodes of gener- alized convulsive seizures post-operative day 1, which were suppressed by administration of diazepam intra- venously. The blood test, brain CT and electroenceph- alogram revealed no significant abnormalities. They were discharged without any neurological complica- tions. The high dose of TA was considered to have caused the seizures, since in previous reports the use of TA during surgery was associated with increased risk for postoperative seizures. It was demonstrated that approximately 40 to 70% of TA is excreted in the urine following intravenous administration. We posit that this might have led to excessive serum concen- tration of TA in our patients. Therefore, the dosage of TA should be decreased judiciously in patients with chronic kidney disease especially on hemodialysis to prevent postoperative seizures.