Thiamine Intervention and Coronary Artery Bypass Grafting

Inclusion Criteria: * Patients with Coronary Heart Disease (CHD) scheduled for Bypass Grafting (CABG) * Thiamine deficiency before CABG * European System for Cardiac Operative Risk Evaluation II (EuroSCORE II) \>1.5% * Off-pump surgery Exclusion Criteria: * Dementia at baseline \[Montreal Cognitive Assessment (MoCA) \<21 within 5 days before CABG\] * Current in-take of thiamine * Known thiamine allergy * Uncontrolled blood glucose levels * Unable to give consent due to illness * History of hyperlactatemia * Recent (within several years and/or up to the judgment of the PI/co-PIs) cerebral incidents (seizure or head trauma resulting in loss of consciousness and/or concussion) * Stroke * Diagnosed psychiatric diseases (clinical depression, schizophrenia, manic-depression) * Patients with history of alcohol or substance abuse * Acute or chronic infections (tuberculosis, hepatitis, or encephalopathy) * Diagnosed neuro-degenerative diseases (Alzheimer's or Parkinson's disease) * Chronic immunodeficiency (including HIV) * Congenital brain deficits will also be excluded