Better equipment, techniques improve heart surgery results

Machines that mimic the chemical reactions found inside your arteries are among the latest innovations in cardiac surgery. Such machines are part of a growing arsenal of new techniques and equipment that surgeons can mix and match for individual patients with individual problems.

Cardiac surgeons are accustomed to change and improvements. The first open-heart surgeries with a heart-lung machine were performed less than 50 years ago.

“This is a fairly young specialty. There has been a tremendous amount of innovation, particularly in the last 10 years,” says Dr. Gabriel Aldea, associate professor of surgery at the School of Medicine and chief of adult cardiac surgery at UW Medical Center.

Aldea and his colleagues at the UW can call on a variety of new techniques that are now tailored to individual patients. As recently as five years ago, patients who needed heart surgery had only a few options. Today, doctors have new knowledge, medications and operating techniques.

One innovation involves biocompatible machinery. To understand how it helps, you have to know a little more about the surgery. During bypass surgery, a machine performs the role of the heart and lungs so the heart can be stopped during the operation. The machine pumps the patient’s blood in and out and gives it oxygen. But the blood doesn’t react naturally in plastic tubes. Blood does the same thing that it does when it senses a wound. It begins to clot. It causes inflammation.

As a result, doctors must give patients anti-clotting medicine during the operation to thin the blood. This process creates a small percentage of risk to the patient. Organs such as the lung may be injured when the blood flow is resumed under these conditions: what doctors call ‘reperfusion’ injuries. Most injuries are temporary and self-limited, but some lead to a delayed recuperation. The process also requires transfusions of blood. In general, the more transfusions, the more possibility of complications.

What doctors would rather do is fool the blood into thinking it hasn’t left the body. One biocompatible machine uses heparin. Heparin is an anti-clotting factor found in many tissues, such as the liver and lungs. A heart and lung bypass machine, pump parts and all, can be lined with chemically bonded heparin. This is part of an improved method that has cut the need for transfusions by 40 percent, and decreased complications in all categories by at least 50 percent. Inventors constantly approach doctors with the newest machinery, which will continue to cut rates of transfusion and inflammation, Aldea predicts.

Research at the UW by Dr. Edward Verrier and colleagues, meanwhile, looks at what’s going on at the cellular level with reperfusion injuries. Verrier is professor and chief of cardiothoracic surgery at UW Medical Center. Their work allows surgeons to better evaluate the effects of different medications and surgical techniques, and to avoid the inflammation associated with reperfusion, Aldea says.

Another technique used by surgeons allows them to perform heart surgery without having to use bypass machinery at all. They can use a small platform that stops motion in the area where they’re working. The heart still beats. This “off-pump” technique is often used on people at risk from the use of bypass machinery, but it may someday replace many bypass surgeries, Aldea says.

In other operations, doctors often use a group of techniques collectively known as minimally invasive surgery. Instead of cutting open the breastbone, doctors use small incisions between the ribs to insert their equipment. These techniques are still relatively new, Aldea says, and they’ve been tried mostly in less serious cases. Patients recover from their surgery more quickly than with traditional methods, and go on to lead normal lives.

“The end result is that the patients are doing better, and they’re getting out of the hospital faster. Surgeons not only use individualized approaches to minimize complications for each specific patient, but are leaders in developing the evolution of varied approaches to make very successful open heart procedures even safer,” Aldea says. ¶

Walter Neary