Effects of Magnesium on Individuals Undergoing Coronary Artery Bypass Graft Surgery

Phase 2

Completed

Conditions: Coronary Disease
Heart Diseases
Cardiovascular Diseases
Neurologic Manifestations

Interventions: Drug: 0.9% saline
Drug: Magnesium

Registration Number: NCT00041392

Lead Sponsor: Duke University

Brief Summary: The purpose of this study is to examine the effects of supplemental magnesium on the neurocognitive function of individuals undergoing coronary artery bypass graft (CABG) surgery.

Detailed Description: BACKGROUND:

Approximately 400,000 individuals undergo heart operations each year and cognitive impairment occurs frequently following surgery. An increasing number of these individuals are elderly and are particularly susceptible to cognitive dysfunction following surgery. Cognitive impairment is most notable in the early stages following heart surgery, but it may persist in some individuals. While many people think cognitive impairment is subtle, transient, or subclinical, perioperative decline is associated with 5-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 heart surgery. However, most strategies have been unsuccessful, met with limited success, or are unrealistic from a cost or risk-benefit ratio for the majority of people. This study will examine the effectiveness of supplemental magnesium at preventing the cognitive decline associated with heart surgery.

DESIGN NARRATIVE:

This study will examine the effect of supplemental magnesium on the neurocognitive function of individuals undergoing CABG surgery. The two hypotheses to be tested include the following: 1) therapeutic levels of magnesium reduce post-operative neurocognitive dysfunction after heart surgery; and 2) therapeutic magnesium levels protect quality of life through reduced cognitive dysfunction after heart surgery. This double-blind study will enroll 400 individuals and randomly assign them to either the treatment group, which will receive 100 mg/kg of magnesium, or to the control group. Anesthesia management will be standardized to minimize any impact that anesthesia may have on neurologic or neuropsychologic outcome. Neurocognitive testing will be conducted prior to surgery, and 6 weeks and 1 year following surgery.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 389

Inclusion Criteria

Coronary heart disease

Exclusion Criteria

Early dementia
History of psychiatric illness

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
0.9 % saline	0.9% saline	100 mg/kg 0.9 % saline
Magnesium	Magnesium	100 mg/kg magnesium

Primary Outcome Measures

Name	Time	Method
Cognitive Function	Measured at baseline and 6 weeks	To characterize cognitive function over time, while minimizing potential redundancy in the cognitive measures, a factor analysis was performed on the cognitive test scores from baseline. We chose a four-factor solution, which represents 4 cognitive domains: verbal memory, abstraction and visuo-spatial orientation (executive function), visual memory and attention and concentration. To quantify overall cognitive function, a baseline cognitive index was first calculated as the mean of the 4 preoperative domain scores. The cognitive index score has a mean of zero and standard deviation of 0.5. Thus, any positive score is above the mean, any negative score is below the mean, and a score of 0.5 represents 1 SD above the mean. A continuous change score was then calculated by subtracting the baseline from the 6-week cognitive index. Negative scores indicate decline and positive scores indicate improvement.

Secondary Outcome Measures