Thiamine Supplementation in High Risk Cardiac Surgery Patients

Thiamine has a pivotal role and is an essential cofactor for pyruvate dehydrogenase activity. Widely known wet beri-beri is developed due to thiamine deficiency and characterized by vasodilatory shock and despaired oxygen extraction leading to kidney, heart and central nervous system dysfunction. Thiamine deficiency is often underestimated and even in primary absence of vitamin B1 deficiency, high-consumptive state of many critical illness and cardiac surgery itself can lead to its lack. Reported that in patients on chronic dialysis and patients with AKI requiring RRT thiamine deficiency is a usual finding. In cross-sectional observational study it has been shown that up to 33% of patients with a diagnosis of congestive heart failure (CHF) had thiamine deficiency due to chronic loop diuretic use. Also reported that 96% of patients (21 of 23) with heart failure receiving loop diuretic therapy (daily dose: 80-240 mg furosemide) developed thiamine deficiency. In prospective observational trial it has been shown that plasma thiamine levels were decreased after CABG surgery.

In a secondary analysis of a randomized, double-blind, placebo-controlled trial conducted in septic patients, thiamine supplementation showed highly-promising renal protective effect. Need for RRT was 8 patients (21%) in placebo group and 1 patient (3%) in thiamine group (p=0.04).

On the other hand it was unable to show any benefit of thiamine supplementation in patients undergoing CABG surgery. Although, postoperative oxygen consumption was significantly increased among patients receiving thiamine.

Nevertheless, existing evidence suggests that thiamine supplementation might be an attractive strategy in counteracting organ dysfunction and thus morbidity and mortality in high-risk cardiac surgical patients.

Inclusion criteria

• Valve surgery + CABG that required cardiac surgery with CPB
• Aged 18 years or older
• Signed informed consent

Exclusion criteria

• Emergency surgery
• Chronic kidney disease of G4-G5 categories according to KDIGO criteria (at least one of the following present for > 3 months: glomerular filtration rate ≤ 29 ml/min/1.73 m2, history of kidney transplantation)
• Known allergy to thiamine
• Pregnancy
• Current enrollment into another RCT (in the last 30 days)
• Previous enrollment and randomisation into the APPLY trial
• Administration of thiamine in the previous 30 day