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First performed in 1985, cardiomyoplasty is an experimental surgery used to treat heart failure. The surgery is performed through an incision between the ribs. During cardiomyoplasty, the surgeon carefully frees up one end of a muscle from the back or abdomen (usually the latissimus dorsi muscle from the back), without disturbing the muscle’s major nerves or blood supply. The surgeon then rotates this “flap” of muscle into the chest and wraps it around the heart. A mechanical device similar to a pacemaker stimulates the muscle to contract in sync with the heart’s own rhythm, helping the heart to beat. This mechanical device has not been approved by the Food and Drug Administration, and no research trials are currently underway in the United States.
Cardiomyoplasty was initially met with enthusiasm because it used the patient’s own tissue, avoiding many of the risks associated with a heart transplant. However, recent research suggests that the procedure may not improve patients’ circulation as much as was originally hoped and only certain patients may qualify for cardiomyoplasty. Studies have shown that the patients with the most advanced heart failure are unable to withstand the surgery. In addition, among patients who could withstand the surgery, the latissimus dorsi muscle is prone to degenerate within a few years, resulting in the need for a heart transplant or additional therapy. In essence, the patients who needed help the most couldn't tolerate the procedure, while those who could benefit from it didn't need to undergo such a traumatic surgery.
Because of these results, the largest American research trial was suspended and the surgery is rarely, if ever, performed in the United States today. The procedure is still being performed in limited numbers in Europe and Japan.
Cardiomyoplasty was developed by Dr. Alain Carpentier, who is also known for two major contributions to the field of cardiology. First, he pioneered surgical techniques to repair rather than replace the mitral valve of the heart. Second, he developed techniques for replacing a human heart valve with that of a pig (a xenograft, using tissue from another species).
While dynamic cardiomyoplasty has largely been abandoned, it did provide physicians with valuable lessons. One such lesson was the value of preventing left-ventricle remodeling. This occurs when the left ventricle expands and weakens, which worsens heart failure. One promising method to slowing remodeling is the use of a heart jacket. This mesh-like net, known as the Acorn device, is still being studied in the United States, but early results have been promising.
Remodeling is most notably characterized by enlargement and thinning of the heart’s left ventricle. There is an increased use of oxygen, greater degree of regurgitation, and decreased ejection fraction. The process is a complex one. Contributing factors include the release of hormones in response to inflammation brought on by heart failure, or the extent to which a person’s genes determine how the heart adapts after it is injured or diseased. Whatever the causes, left ventricular remodeling sets in motion an unhealthy domino effect, as progressive damage to heart cells leads to reduced cardiac output and more severe heart disease.
The mesh-like material of the heart jacket supports the ventricles (the heart’s lower chambers), providing a snug fit without constricting the heart, while supporting function of the mitral valve. In pre-clinical studies, the support device demonstrated that it did more than keep the left ventricle from enlarging. It can actually reshape and restore it to a more normal form. This led to a significant decrease in the process of self-destruction of heart muscle cells – another hallmark of heart failure. There was a rise in cardiac output as well as improved ejection fraction and a reduced need for heart transplant.
However, the device has not been approved for use in humans by the Food and Drug Administration (FDA). In 2005, the device was denied approval in the United States after the FDA recommended that more studies were needed.
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