Heart Bypass Surgery May Increase Bone Fracture / Osteoporosis Risk
When one or more of the coronary arteries becomes partially or totally blocked, the heart does not get an adequate blood supply. This is called ischemic heart disease or coronary artery disease (CAD). It can cause chest pain ( angina ). Heart bypass surgery creates a detour or "bypass" around the blocked part of a coronary artery to restore the blood supply to the heart muscle. The surgery is commonly called Coronary Artery Bypass Graft, or CABG .
However,coronary bypass surgery is a common procedure used to divert blood around blocked arteries in the heart. Coronary bypass surgery remains one of the gold standard surgical treatments for coronary artery disease.Coronary bypass surgery uses a healthy blood vessel harvested from your leg, arm, chest or abdomen and connects it to the other arteries in your heart so that blood is bypassed around the diseased or blocked area.
In coronary artery bypass graft surgery, blood vessels are taken from other parts of your body and attached to the blocked coronary arteries on either side of the blockage. The blood is then able to flow around, or bypass, the blockages. You will likely stay in the hospital about 1 week, and then recover at home for several weeks.
Coronary artery bypass surgery is performed by a team of surgeons. The operation takes 4 to 6 hours, depending on how many blood vessels need to be bypassed. Pieces of veins or arteries are taken from the legs and sewn into the arteries of the heart to bring blood past a blockage and increase the blood flow to the heart. Bypass surgery is usually done when angioplasty isn't possible or when your doctor feels it's a better choice for you.Your surgeon will make a cut in your chest and divide your sternum, which is the flat bone in the center of the chest. He or she will connect you to a heart-lung machine that will take over the work of your heart and lungs during the operation.
Neurological dysfunction is a common complication after cardiac surgery. A history of diabetes, hypertension, increased age, preoperative neurological event, aortic atheromatous / calcific disease, bilateral carotid artery disease, intermittent aortic cross clamping and evidence of mural thrombi are all co-related with increased risk of neurological damage after CABG. When analyzed in a stepwise logistic regression model, diabetes mellitus, aortic disease increased age and mural thrombi carried a higher probability that the patient would have a postoperative neurological deficit.
Some people experience a decline in memory and other cognitive functions after undergoing coronary bypass surgery. Predictors include older age, high blood pressure, lung disease and excessive alcohol consumption. Of those people who do lose some cognitive ability, most gradually regain their intellectual abilities within six to 12 months. Bypass surgery doesn't cause dementia, but it may worsen any pre-existing mental decline, including early dementia.
Another risk of coronary bypass surgery is that plaques — the fatty deposits that accumulate on the inner walls of coronary arteries and other vessels in atherosclerosis — may break loose from the walls of the aorta when it's clamped shut for the heart-lung machine. Debris from the ruptured plaques may lodge in the brain, causing a stroke. By using new imaging techniques, however, surgeons have a better chance of placing the clamps in areas of the aorta that are free of plaques.
In the year following coronary artery bypass grafting (CABG), bone mineral content declines significantly in men, according to findings published in the American Journal of Cardiology. Declines in bone mineral have been shown to increase the risk of fracture.
Dr. Larry E. Miller, of Virginia Polytechnic Institute and State University, and colleagues evaluated changes in bone mineral and body composition in 26 men, between the ages of 50 and 79 years, who underwent CABG. In each patient, blockages were removed in more than one coronary artery, the blood vessels that pass through the heart to provide oxygen-infused blood to the rest of the body.
The investigators performed dual-energy X-ray absorptiometry, a method of measuring bone mineral content, before surgery and at 3 months and 1 year after treatment.
Bone mineral density had decreased in the arms, pelvis and the total body by 3 months after treatment. The bone mineral content was also reduced by 4.9 percent in the arms, and losses in the legs and total body approached statistical significance.
There were also statistically significant decreases in fat-free mass in the arms and total body, but not in the legs. No changes in total body or regional fat mass were detected.
Of the 26 subjects, 15 returned for 1-year follow-up. Bone mineral density in the total body and the legs was still significantly decreased, and it was also decreased in the arms.
There were no changes observed in total body or regional body composition by the 1 year after 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," 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," Miller recommended. The sternum, or breast bone, is the flat bone in the chest that the heart surgeon must cut through to get to the damaged arteries.
"This regimen may prevent or slow the dramatic bone mineral losses that were observed in our study."