Hydroxychloroquine and Cognitive Function After Surgery

Inclusion Criteria: 1. Male or female, age ≥ 50 years old. 2. Patients scheduled to undergo cardiac surgery (CABG, CABG + Valve, Valve) with CPB. 3. Patient has voluntarily signed and dated the study-specific informed consent form approved by Duke University Health System Institutional Review Board (DUHS IRB) Exclusion Criteria: 1. Cardiac surgery scheduled to be performed without cardiopulmonary bypass 2. Patients requiring emergent operation 3. Patients with a history of myocardial infarction within 7 days of surgery 4. Patients with a history of porphyria, psoriasis, chronic dermatitis, or retinal disease 5. Patients receiving preoperative digoxin 6. Patients with symptomatic cerebrovascular disease with substantial residual deficit 7. Patients with a history of alcohol abuse within 2 years of screening 8. Patients with a history of psychiatric illness and/or anxiety requiring medical treatment. 9. Patients with impaired liver and/or kidney functions (AST, ALT 2 times the upper limit of normal) 10. Patients with impaired renal functions (GFR \< 30ml/min) 11. Patients with less than a 7th-grade education or unable to read and thus unable complete the neuropsychological testing 12. Patients scoring \< 26 on a baseline Mini Mental State examination (MMSE) or scoring \>27 on the Center for Epidemiological Studies - Depression (CES-D) scale 13. Female subjects of childbearing potential who have had menstrual period within the past two years 14. Patients with bodily implants unsafe for MRI use 15. Patients with a history of claustrophobia 16. Known or suspected hypersensitivity to quinine (chloroquine or hydroxychloroquine) 17. Patient with pre-existing diagnosis of G6PD deficiency 18. Patients who have participated in another interventional clinical study within the previous 30 days 19. Any other concurrent disease or illness that, in the opinion of the investigator, makes the patient unsuitable for the study 20. Major ophthalmologic comorbidities (ex: ruptured globe, retinal vascular occlusive disease, retinal artery occlusion, anterior ischemic optic neuropathy, media opacification due to corneal abnormalities or cataract that prevent ocular and optical coherence tomography examination, glaucoma, age-related macular degeneration, history of intravitreal injections, and macular edema) 21. Patients who have received chemotherapy in the last 12 months 22. Patient with a QTc of 450 msec or greater (or 500 msec or greater in those with known IVCD, RBBB, or LBBB) at baseline will be excluded.