Difficulty in thinking is a widespread problem following bypass surgery, reported at many institutions. Since 1992, the Wake Forest research team has been investigating these cognitive complications following bypass surgery which normally employs the heart-lung machine. They developed methods to track the causes of the complications and test techniques to reduce the complications. They have also been developing methods for doing coronary artery bypass without using the heart-lung machine.

In the new study of 237 patients, the team compared the standard method of coronary artery bypass using the heart-lung machine with surgical techniques that minimized movement of the aorta while still using the machine. Movement was reduced by using a single clamp that exerted significantly less force on the aorta than the standard cross clamp. Surgery without the machine was also compared.

The researchers gave the patients a battery of 11 psychological tests before surgery, then at three to five days after surgery, again between three and six weeks and again at six months. The tests measured such things as fine motor function, verbal and nonverbal memory, attention and concentration.

In the week after surgery, at least 60 percent of the patients in all three groups showed neurological deficits. The number of patients with deficits declined steadily in both the group without the heart-lung machine, and the group with minimal movement of the aorta. By six months, only 32 percent of the patients who didn't use the machine and 30 percent of the patients who had minimal aortic movement had deficits, suggesting less permanent injury in both groups. But 57 percent of the patients who had the traditional surgery still had deficits at six months, the researchers reported.

MEDICA.de; Source: Wake Forest University Baptist Medical Center