Sustained high-dose thiamine supplementation in high-risk cardiac patients undergoingsurgery under cardiopulmonary bypass (apply trial): a pilot study

Introduction Numerous studies showed that relative thiamine depletion in critically ill patients and in patients undergoing cardiac surgery may contribute to cardiac dysfunction and hyperlactatemia leading to adverse outcomes. Thus, in preparation for a larger trial, we performed a pilot, randomized, placebo-controlled feasibility trial of sustained thiamine supplementation in high-risk patients undergoing cardiac surgery under CPB. Methods Forty patients who underwent high-risk cardiac surgery under CPB were randomly assigned to receive either 200 mg of Thiamine or placebo intravenously after anesthesia induction; after CPB; on the evening of the day of surgery; on three postoperative days (twice a day). Primary endpoints were successful compliance with protocol and successful recruitment of patients. Secondary endpoints included: vasoinotropic score and norepinephrine equivalent dose, postoperative peak lactate and creatinine levels, incidence of acute kidney injury, daily SOFA score, rate of postoperative complications, incidence of adverse events, 7-day and 30-day mortality. Results The mean recruitment rate was 6.6 patients per month (1.6 patients per week). Compliance with protocol was excellent as all patients enrolled into the study received all assigned intervention. No patients develop allergic reactions to the study drug. All patients completed the 30-day follow-up. There were no differences in secondary endpoints. Statistical analysis performed with the Stata Statistical Software using Mann-Whitney U test, T test of Student and ANOVA. Discussion The rationale for thiamine administration in patients undergoing cardiac surgery comes from results of several studies that showed a high incidence of thiamine deficiency postoperatively. Our study implies that it is feasible to achieve an acceptable recruitment rate in a typical tertiary institution with full compliance with the protocol and it's not associated with major safety concerns in patients receiving complex cardiac surgery.