To examine the effects of supplemental magnesium on the neurocognitive function of patients undergoing coronary artery bypass graft (CABG) surgery.

BACKGROUND: Cognitive impairment occurs frequently after surgery in the approximately 400,000 patients who undergo cardiac operations each year. An increasing number of these patients are elderly, and this patient population is particularly susceptible to cognitive dysfunction after cardiac surgery. Cognitive impairment is most notable in the early phases after cardiac surgery, but persistence occurs in an important percentage of patients. While adjectives such as "subtle," "transient," and "subclinical" have been used due to the apparent transient nature of decline, perioperative decline is associated with five year cognitive deterioration and reduced quality of life. Multiple strategies, both clinical and pharmacological, have been proposed to reduce the central nervous system dysfunction associated with cardiac surgery. However, most have been unsuccessful, met with very limited success, or are unrealistic from a cost or risk-benefit ratio to be applied to the majority of patients. The trial tests the ability of supplemental magnesium to prevent the decline.

DESIGN NARRATIVE: The randomized trial examines the effects of supplemental magnesium on the neurocognitive function of patients undergoing CABG surgery. The hypotheses to be tested are: Therapeutic levels of magnesium reduce post-operative neurocognitive dysfunction after cardiac surgery; Therapeutic magnesium levels protect quality of life through reduced cognitive dysfunction after cardiac surgery. This clinical trial will enroll 400 patients and randomly assign them to one of two groups: treatment (100 mg/kg of magnesium) or control group with all the investigators and assessors blinded to group assignment. Anesthesia management will be standardized to minimize any impact that anesthesia may have on neurologic or neuropsychologic outcome. Neurocognitive testing will be conducted preoperatively (baseline), six-weeks and one year post-surgery.

Genders Eligible for Study:  Both

Criteria