Reduction in brain embolization using the aegis aortic cannula during bypass in swine

Background. Cerebral embolization during cardiopulmonary bypass (CPB) is an important cause of neurologic injury. This study determined whether a new aortic cannula (Cardeon Aegis) could substantially reduce brain embolization in a swine CPB model. Methods. Fourteen 70-kg pigs underwent normothermic CPB, 7 animals with the Aegis device and 7 with a control cannula. Cerebral blood flow was determined using 15-μm fluorescent microspheres before bypass and twice during CPB. After the second bypass CBF measurement, animals were embolized with 120,000 78-μm fluorescent microspheres at normothermia. At the end of the experiment the brain, eyes, kidneys, myocardium, and small bowel were removed and the microspheres isolated. Results. Cerebral blood flow was equivalent between groups before bypass and during both bypass periods. While the two groups were equivalent with regard to pump flow, temperature, hemoglobin, and PaCO2, use of the Aegis cannula markedly reduced embolization to three of four brain regions. Deployment of the baffle reduced total brain embolization by 91% from a mean of 22 ± 21 emboli per gram in the control animals to 2 ± 6 emboli per gram in animals receiving the Aegis device. Conclusions. Cerebral blood flow with the Aegis device is equal to or greater than that observed under nonbypass conditions and that seen with conventional aortic cannulas. However, cerebral embolization is profoundly reduced by use of the Aegis device. The application of this cannula may reduce postcardiac surgical neurologic injury.