When surgeons devised ways to operate on a beating heart, many believed this approach would phase out the use of the heart-lung machine, the device that paved the way for life-saving open heart surgery. Not so, reports the March 2013 Harvard Heart Letter.

The heart-lung machine, first used in 1953, adds oxygen to blood and circulates it around the body. This lets doctors stop the heart, making it safer and easier to bypass cholesterol-clogged coronary arteries or fix other cardiac problems. While the machine helped save and improve countless lives, some experts blamed the heart-lung machine (also known as the pump) for the foggy thinking and memory loss that sometimes follows bypass surgery. In an effort to avoid this problem, surgeons developed ways to operate on the heart while it continued to beat, avoiding the pump.

Yet "off-pump" bypass surgery hasn't eliminated use of the heart-lung machine. In fact, it is still used in three-quarters of bypass operations. Most experts agree that off-pump bypass surgery makes sense for people who are at high risk for developing complications from the heart-lung machine, like those who have had a stroke or have a fragile aorta, the body's largest blood vessel. But among people at normal risk, surgeons remain divided on the use of off-pump bypass.

Dr. Kamal Khabbaz, chief of cardiac surgery at Harvard-affiliated Beth Israel Deaconess Medical Center, uses this approach only when he feels he must. At the other end of the spectrum, Dr. John Byrne, the new chief of cardiac surgery at Harvard-affiliated Brigham and Women's Hospital, performs nearly all bypass operations off pump.

Both methods are remarkably safe when performed by an experienced surgeon backed by a skilled team, reports the Harvard Heart Letter. And so far, there isn't solid evidence that the heart-lung machine is what's behind the loss of memory and thinking skills that sometimes follows bypass surgery. So how should a person needing the operation choose between the two?

"Find a good cardiologist who refers to a good surgeon. The surgeon is the captain of the ship and will choose whether an operation should be performed on- or off-pump," advises Dr. Byrne.

Read the full-length article: "Should bypass surgery be done off pump?"