Does routine use of aortic ultrasonography decrease the stroke rate in coronary artery bypass surgery?

PURPOSE

The purpose of this study is to determine whether the routine use of intraoperative surface aortic ultrasonography decreases the stroke rate in coronary artery bypass graft surgery (CABG).

METHODS

One hundred ninety-five consecutive patients undergoing CABG between July 1, 1992, and June 30, 1993 (study group), were evaluated by intraoperative surface aortic ultrasonography. Based on information obtained, changes in the operative technique were made in an effort to decrease the incidence of embolic stroke from unsuspected atherosclerotic disease of the ascending aorta. The outcome of these patients was compared with that of 164 consecutive patients who underwent CABG between July 1, 1991, and June 30, 1992 (control group), in whom the ascending aorta was assessed by inspection and palpation only.

RESULTS

Significant disease was detected in three (2.0%) of 164 patients in the control group. Modifications in their operative technique consisted of hypothermic fibrillatory arrest with no cross-clamping of the aorta and left ventricular venting in two patients and single cross-clamping in one patient. There were five strokes overall in this group (3.0%), and six patients died (3.6%), one in whom the stroke contributed directly to the cause of death. In the study group the ultrasonic findings were normal to mild in 168 patients, moderate in 20 patients, and severe in seven patients. These results led to a modification of the technique in 19 patients, (10%): hypothermic fibrillatory arrest with no cross-clamping of the aorta and left ventricular venting in 14 patients, modification in the aortic cannulation site or single cross-clamping in three patients, and modification in placement of proximal anastomoses or all arterial grafts in two patients. No strokes occurred in this group (p < 0.02, Fisher's exact test). Five patients died, for an operative mortality rate of 2.6%.

CONCLUSION

These data indicate that intraoperative ultrasonography of the ascending aorta with simple modifications in operative technique reduces the stroke rate in CABG.