What is bypass surgery?

Indications and Procedures

Coronary artery bypass surgery
is needed when angiography reveals a narrowing or blockage in heart
arteries causing angina that cannot be controlled by medication or relieved by angioplasty. The traditional method of open chest
bypass surgery, which first became popular in the 1970s, requires that the patient be fully anesthetized. The surgeon cuts open the patient’s chest, saws through the breastbone, and spreads the halves of the ribcage to expose the heart. The heart is stopped and cooled, and the major heart vessels are attached to a heart-lung machine, which oxygenates and circulates the blood. At the same time, another surgeon removes a leg vein and prepares grafts to be sewn around blockages in the heart arteries. Mammary arteries are also employed to redirect blood flow around obstructed arteries. After the bypasses are satisfactorily implanted, the heart-lung machine is disconnected and the heart resumes pumping on its own. The two halves of the breastbone are reattached with stainless steel wire, and the incision is sewn closed. Patients are taken to a cardiac intensive care unit overnight and are normally discharged from the hospital within a week. They recover fully in one to three months.

Bypass surgery of the peripheral arteries, usually those of the legs, is indicated when ischemia
causes severe pain. Sections of leg veins and grafts made of synthetic material, such as Dacron, are used to bypass obstructions and to open blood flow to the legs.

An obstruction in the intestines can be treated surgically by removing the blocked region and sewing together the healthy portions of the gut. Severe problems may require creating an opening for the digestive tract through the abdominal wall, called a stoma, through which its contents can empty into a removable plastic bag. The procedure may be permanent or temporary, to allow the affected gut to heal. After successful healing, the bypass and bag are removed and the intestine segments are reattached.

Removal of part of the stomach or small intestine is sometimes used to treat cases of extreme obesity. The operation improves the patient’s quality of life and may also extend its duration.

Uses and Complications

Traditional coronary artery bypass surgery is profoundly invasive. The heart-lung machine can create problems, even though newer machines are less stressful than the original models. The action of the pump is more powerful than that of a normal heart and can generate turbulence that damages blood cells and other organs. The machines have been blamed for blood clot formation, causing strokes and heart attacks during an operation. Patients, especially the elderly, often experience memory loss and confusion following surgery; though usually temporary, the problem can last for years. Surgeons, therefore, have been seeking less stressful and invasive methods of treating coronary artery disease.

Neither peripheral artery surgery nor intestinal bypass surgery involves using heart-lung machines, but the large incisions commonly used in such operations can also lead to complications by exposing extensive body areas to possible infection. Although traditional surgery is highly successful, innovators continue to seek the development of less invasive procedures.

Perspective and Prospects

The goal of research is minimally invasive surgery. Intestinal surgeons led the way with the development of laparoscopic
gallbladder and kidney stone surgery in the 1980s. Only small circular incisions are needed to insert a fiber-optic instrument that transmits enlarged images of the surgical site to a screen. Laparoscopic tools are introduced though several additional small incisions. Segments of bowel can then be removed though tubes and their ends joined without opening the abdomen. The use of laparoscopic techniques reduces the tissue damage caused by traditional surgery. The patient feels less pain after the operation, experiences a shorter hospitalization, returns to normal activity sooner, and develops a smaller scar.

To avoid use of the heart-lung machine, and its medical complications, cardiac surgeons have experimented with open chest surgery on a beating heart. This very delicate operation involves temporarily immobilizing the area of the heart where the surgeon intends to attach a graft, slowing the heartbeat with drugs, and stitching the bypass into place between heartbeats. Only the most skilled surgeons succeed in mastering this difficult technique.

In the 1990s, cardiac surgeons, following intestinal surgeons, adopted the use of fiber-optic tubes that permit so-called keyhole surgery. Incisions of 3.0 inches in the chest and holes 0.5 inch in diameter under the armpit are sufficient to gain entry to the heart, thereby eliminating any need to open the chest cavity. Immobilizing segments of the heart and sewing grafts to the rhythm of the heartbeat, however, is considerably more difficult when done through a tube while viewing a television screen. In the twenty-first century, surgeons have begun using computer-controlled robots to carry out the intricate maneuvers needed to repair ailing hearts.

In May 2013, a study published in the Annals of Thoracic Surgery
suggested that short-term use of antidepressant medications aid in mental and emotional recovery following bypass surgery.

Bibliography

"Coronary Artery Bypass Grafting." Health Library, September 26, 2012.

Doherty, Gerard M., and Lawrence W. Way, eds. Current Surgical Diagnosis and Treatment. 12th ed. New York: Lange Medical Books/McGraw-Hill, 2006.

Emery, Robert W., ed. Techniques for Minimally Invasive Direct Coronary Artery Bypass (MIDCAB) Surgery. Philadelphia: Hanley & Belfus, 1997.

Klaidman, Stephen. Saving the Heart: The Battle to Conquer Coronary Disease. New York: Oxford University Press, 2000.

Pittman, Genevra. "Heart bypass surgery or stents? Depends on patient." MedlinePlus, April 22, 2013.

Preidt, Robert. "Antidepressants May Hasten Bypass Recovery, Study Finds." MedlinePlus, May 1, 2013.

Youngson, Robert. The Surgery Book: An Illustrated Guide to Seventy-three of the Most Common Operations. New York: St. Martin’s Griffin, 1997.