Diagnosis and management of cerebral malperfusion phenomena during aortic dissection repair by transesophageal Doppler echocardiographic monitoring

BACKGROUND:
Early diagnosis and surgical decision making are the key for survival in acute type A aortic dissection (AAD-A). As such, transesophageal echocardiography (TEE) is widely accepted tool in the diagnosis of AAD-A.

METHODS:
We used TEE in 49 cases as the sole diagnostic examination of AAD-A since November 1989. It was particularly useful intraoperatively to detect cerebral malperfusion during AAD-A repair. We were able to accurately monitor the blood flow of the aortic arch by using TEE for all patients throughout the operation. Only two patients developed severe cerebral malperfusion after the distal anastomosis was finished under deep hypothermic circulatory arrest. TEE showed that the malperfusion after the bypass was re-established. In both cases the expanded false lumen blocked the true lumen. We immediately switched the perfusion cannula from the femoral artery to the ascending aortic graft to create antegrade flow.

RESULTS:
The subsequent TEE showed only the flow in the true lumen. One patient recovered without any complication while the other suffered mild, temporary neurological defects. Cerebral malperfusion is a potential catastrophic complication of AAD-A, which may exist before surgery or be caused by the operation itself.

CONCLUSIONS:
We recommend continuous intraoperative TEE to monitor aortic arch flow during these operations. This allows immediate detection of cerebral malperfusion and prompt action can be taken to prevent irreversible brain damage.