Intraoperative Malperfusion Events

Abstract

It is important to call attention to two situations of intraoperative malperfusion. These require speedy recognition and remedy in order to avoid lethal outcome.

Questions and Answers

• SP: When would you consider an emergent TEVAR vs. open repair of an intra-operative type B dissection ?

• JAE: That is a great question, Shamini. Endovascular techniques provide a considerable arsenal of potential solutions for perfusion-related descending dissections. We have employed stents for such situations. It is important to keep stenting in mind. I do believe that most descending dissection phenomena incurred via retrograde perfusion will settle down once native antegrade flow has been re-established.

• SP: If you are on pump and a dissection occurs, will there be change in line pressures?

• JAE: Yes, this will usually occur, as the blood cannot flow as freely as before through the freshly dissected aorta. Retrograde dissection should be in everyone’s mind in case of rise in line pressures. It is important to check for this. The intraoperative TEE provides a sensitive method for ruling out intraoperative descending aortic dissection from retrograde perfusion. Of course, and thankfully, usually the cause of elevation of line pressure is more mundane, such as a kink in the line, or your assistant’s leaning on the line.

• SP: If the patient is not able to wean quickly off CPB, how would this change your strategy in treating the malperfusion event?

• JAE: As mentioned, I have usually weaned bypass quickly and the problem has gone away. However, if you are too cold to wean, or if myocardial performance does not permit weaning, you should switch to antegrade perfusion. Probably your new ascending/arch graft is the best site to cannulate.

• SP: What are some proactive measures one can take to prevent this from happening intra-operatively?

• JAE: Most importantly, do not perfuse through a compromised ileo-femoral system. Imagine how high the intraluminal pressure will rise if the perfusionist is trying to pump the entire cardiac output through a stenosed iliac artery. Dissection or rupture, or both, is likely to occur. Always be sure you have felt the femoral pulses before you cannulate and that you have checked the aortoiliac system on your CT scan.

• SP: Why do you keep both cannulas in place when you have a dissection from femoral perfusion? That is, why do you have second arterial cannula and not remove previous femoral cannula?

• JAE: You could probably remove the femoral cannula, but you have other fish to fry at that time.