NEW YORK (Reuters Health) - In the year following coronary artery bypass grafting (CABG), bone mineral content declines significantly, according to findings published in the March issue of the American Journal of Cardiology.

Dr. Larry E. Miller, of Virginia Polytechnic Institute and State University, and colleagues examined changes in bone mineral and body composition in 26 men (between the ages of 50 and 79 years) who underwent CABG for multivessel coronary disease. The investigators performed dual-energy x-ray absorptiometry before surgery and at 3 months and 1 year after treatment.

Bone mineral density decreased in the total body, arms, and pelvis through 3 months after treatment. Bone mineral content of the arms decreased 4.9% and losses in the legs and total body approached significance.

There were decreases in fat-free mass in the arms (-0.3 kg; p = 0.002) and total body (-0.7 kg; p = 0.07). No decrease in fat-free mass in the legs was observed. There were no changes in total body or regional fat mass.

Of the 26 subjects, 15 returned for dual-energy x-ray absorptiometry at the 1-year follow-up. Compared to pre-treatment values, bone mineral density of the total body and legs was decreased at 1 year. Losses at the arms approached significance. Bone mineral content of the arm decreased 7.6%.

There were no changes observed in total body or regional body composition over the 1-year post-treatment period.

"Because there is a strong correlation between bone mineral and fracture risk, CABG patients may be at increased risk for osteoporotic fractures unless preventative steps are taken to minimize bone losses," Dr. Miller commented to Reuters Health. "Cardiac rehabilitation, which includes upper body flexibility exercises, should be undertaken as soon as possible post-CABG surgery in appropriate patients," he advised.

"Formalized low-intensity resistance training regimens should be initiated later (approximately 3 to 4 months) in low-moderate risk patients and only after the sternum is fully healed," Dr. Miller recommended. "This regimen may prevent or slow the dramatic bone mineral losses that were observed in our study."