Objective: To test the feasibility and investigate possible cardiovascular effects of a sustained high-dose intravenous thiamine protocol in patients undergoing combined valvular and coronary artery bypass graft surgery.
Design: Randomized, placebo-controlled, pilot feasibility trial.
Setting: Cardiac surgery department of a tertiary hospital.
Participants: Forty patients undergoing combined valvular and coronary artery bypass surgery.
Interventions: Intravenous thiamine (600 mg on the day of surgery, and 400 mg/day on postoperative days 1, 2, and 3) or placebo.
Measurements and main results: The primary feasibility endpoints were recruitment rate and protocol compliance. Secondary endpoints included markers of possible biological and physiological effects. The mean recruitment rate was 8 patients per month and protocol compliance was 97.5%. There were no differences in median peak postoperative lactate (2.7 mmol/L [interquartile range [IQR] 1.4-4.6] for thiamine v 2.5 mmol/L [IQR 1.4-3.6] for placebo; p = 0.53), median peak postoperative creatinine (104 µmol/L [IQR 92.5-129] for thiamine v 99 µmol/L [IQR 86.5-109.5] for placebo; p = 0.53), median nadir postoperative cardiac index (1.8 L/min/m2 [IQR 1.5-2.1] for thiamine v 2.2 L/min/m2 [IQR 1.5-2.5] for placebo; p = 0.25), or the number of patients on vasopressor/inotropic agents (thiamine, 12 [63%]; placebo, 12 [60%]; p = 0.80), or in the total inotrope/vasopressor dose 0.14 µg/kg for thiamine v 0.12 µg/kg for placebo; p = 0.88).
Conclusions: A double-blind trial of sustained high-dose intravenous thiamine supplementation in higher-risk cardiac surgery patients was feasible and appeared to be safe. However, such treatment did not demonstrate evidence of biological or physiological effects.
Keywords: cardiac index; cardiopulmonary bypass; feasibility; mean arterial pressure; open-heart surgery; thiamine.
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