Ultrasonic plaque density of aortic atheroma and stroke in patients undergoing on-pump coronary bypass surgery.

OBJECTIVE

The purpose of this study was to determine the relationship between the aortic atheromatous plaque echo density and the incidence of postoperative stroke or embolic events in patients undergoing on-pump coronary artery bypass grafting (CABG).

PATIENTS AND METHODS

Three hundred and fourteen patients who received on-pump CABG alone were studied. Images of the aortic plaques obtained using transesophageal echocardiography were transferred to a computer. Using an image analysis program, a histogram for plaques more than 3 mm in thickness was obtained through the gray tone frequency distribution of the pixels (0-225). The gray scale median (GSM) was used as a measure of plaque echo density.

RESULTS

Fifty-eight plaques in patients not associated with postoperative stroke or embolic events had GSM ranging from 58 to 241 (151.0+/-38.2), while 9 plaques in patients associated with stroke or embolic events had GSM ranging from 67 to 130 (90.6+/-21.3, p<0.001). The incidence of stroke or embolism was 58.3% when GSM of plaque was less than 100, while it was 3.6% when plaque GSM was more than 100 (p<0.001).

CONCLUSION

This study indicated that computer analysis of aortic atheromatous plaque was useful for selecting patients who had a high risk of postoperative stroke or embolism when receiving on-pump CABG, and for decreasing the incidence of them.