Patients will have blood drawn (total of 1-2 teaspoons over 3 days). We will take these samples before their surgery, when their surgery is completed, and 24, 48, and 72 hours after surgery. We will be checking their troponin I and troponin T, homocysteine, Vitamin B12, and folate levels. We will also take a blood sample to determine their MTHFR genotype and perform a 12-lead EKG. Before and after surgery for patients in Arm A or B, will receive either vitamin B12 (1 mg) and folic acid (5 mg) (or placebo) added to their IV infusion. We also plan to use a non-invasive test known as a nerve conduction study to measure the function of their nerve system. Briefly, 2 small electrodes are attached to their skin over a nerve and, like an EKG, faint electrical pulses are generated and recorded. A typical nerve conduction measurement lasts about 10 minutes.