A New Technique For Coronary Bypass Surgery
16 Feb 2003
How would you like to stitch together two small vessels the size of a piece of spaghetti while riding a bucking bronco? And realize that if you failed the patient would die? This is a tedious task under the best of circumstances. That’s why cardiovascular surgeons have shied away from performing coronary bypass operations on a beating heart. Now, a new technique is being used for some bypass cases without the heart skipping a beat.
This year over 500,000 coronary artery bypass grafts (CABGs) will be performed in North America. The majority will be done by placing patients on a heart-lung machine during the operation. This allows surgeons to suture tiny vessels onto motionless hearts while the heart-lung machine pumps well oxygenated blood to the rest of the body. But stopping the heart and passing blood through the heart-lung machine has a downside. And I was acutely aware of this risk five years ago as I myself faced bypass surgery.
The big risk? Stroke. A recent report from Johns Hopkins University claims that three percent of patients on the heart-lung machine have confronted this problem. It happens because the aorta, the main artery of the body has to be clamped during this procedure. But squeezing an often old, atherosclerotic aorta demands a price. On occasion the pressure dislodges a chunk of fatty plaque which travels to the brain, causing stroke.
One other concern bothered me. Would I be as sharp mentally after the CABGs? A report in the New England Journal of Medicine claims that conventional bypass surgery causes a decline in mental sharpness that may persist for years. 50 percent of patients suffer short-term memory loss and 40 percent show some degree of mental impairment five years later.
Another report claims that seven percent of patients suffer seizures, delirium, confusion and coma. The suspicion lurks as well, that the heart-lung machine triggers inflammation that can affect other organs resulting in kidney failure.
I may be living in a fool’s paradise but I believe I was lucky and escaped these problems. My wife and others might think otherwise!
What is known as "off-pump" bypass surgery has been available for just a few years. During this procedure surgeons immobilize only a small part of the heart’s muscle using a stabilizing device.
Off-pump bypass surgery is also being done in select centers with the help of robots. In this procedure two robotic arms along with a flexible viewing tube are inserted into the chest through tiny incisions. This allows the surgeon to carry out the operation without opening the chest.
An unopened chest and off-pump surgery mean less postoperative pain, decreased risk of infection and patients can be discharged earlier. This technique also removes the potential problems associated with the pump.
Are the results better when operating on a beating heart? A report in The Annals of Thoracic Surgery compared 8,069 patients who had their surgery performed the conventional way using the pump with 2,320 who had their surgery while the heart was beating. The study showed that patients who had the conventional surgery were twice as likely to suffer postoperative stroke.
But not all patients are suitable candidates for either off-pump or robot surgery. Some patients have coronary arteries that are not easily accessible. And women often have small, narrow blood vessels requiring conventional surgery. And when several coronary arteries are involved the pump is necessary.
Good sense indicates that if you can eliminate the pump so much the better. So it’s reasonable to assume that in the future, bypass surgery will be done more often on the beating heart with the help of robotic hands.
But new techniques are not learned overnight. Rather, there is a steep learning curve before surgeons become adept at this procedure. So today I would still prefer a surgeon who had done a thousand conventional bypass operations to one who has done 10 off-pump procedures. "Practice makes perfect" and technical expertise is the first requirement in this type of delicate surgery.
