P184. Isolated Cerebral Perfusion to Protect the Brain during Complex Cardiac Operations

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Isolated Cerebral Perfusion To Protect The Brain During Complex Cardiac Operations

Objective: To demonstrate that single vessel cannulation of the innominate artery or either carotid, prior to and until the cessation of systemic cardiopulmonary bypass, prevents neurological injury in complex cardiac cases.

Methods:
We used separate perfusion circuits for the body and the brain in 41 consecutive patients (Age range 48-82 years) between 2020-2022.

The technique:
• Direct single vessel cannulation of the innominate or either carotid artery with a 12 or 14 F catheter.
• Flow of 1 L/m via this catheter provides adequate brain perfusion at temperatures between 200 and 370C.
• Perfusion of the brain is begun before perfusion of the body and maintained until after cessation of systemic CPB.
• A vascular clamp placed below the cannula assures that all flow goes cephalad.
• We have learned that when we maintain cerebral flow at 1L/minute, flow up the other vessels is negligible and irrelevant.
• This approach essentially isolates the cerebral circulation from the rest of the body and thereby deters antegrade cerebral embolism.
• We manage systemic circulation with standard cannulation (central or peripheral as required).
• We use separate heat exchangers for each circulation to meet the separate metabolic requirements of body and brain.

For instance, in a typical Type A dissection, we begin brain perfusion first. A minute later we start systemic perfusion. The isolated brain perfusion prevents embolization of debris from the layers of the dissected aorta. We then cool the brain to 20-240C the body to 320C.

When we restart systemic circulation, we are rewarming from 320C. Compared to cooling the body to 18-200 C, our technique saves 60-90 minutes of CPB rewarming time and decreases bypass hematological perturbations. We continue cerebral perfusion until CPB to the body is discontinued.

In some of our cases the brain required protection but not hypothermia. The commonest reasons were proximal arch aneurysm repair where the clamp is placed between the innominate and left carotid artery (n=18). Another reason is dangerous sternal re-entry (n=4) where the aorta was adherent to the back of the sternum. Cannulating either carotid artery in the neck and perfusing the brain at 1L/min before opening the sternum eliminates the danger of cerebral injury. In patients with grade 5 atheromata in the arch (n=5) using this technique the brain is protected.

Our case mix is listed in Table below.

Underlying Diagnosis #patients
Acute Type A Dissection 7
Total Arch Reconstruction 6
Dangerous Re-entry Operations 4
Grade V Arch Atheromata 5
Proximal Arch Aneurysm 18
Aortic cannulation error 1

Results:
We have used this technique in 41 consecutive patients in the past three years. There were no strokes, encephalopathy or need for mechanical circulatory support.
There were two late deaths due to respiratory failure and failure to thrive.

Conclusion:
In this cohort, isolated single vessel brain perfusion begun before cardiopulmonary bypass to the body and extended until the operation is complete, provides excellent neurological protection and shortens overall cardiopul

Authors
Salim Aziz (1), Vincent Gaudiani (2), Pei Tsau (3), Keith Korver (4), Paul Shuttleworth (5), Jenna Aziz (6), Salim Aziz (7)
Institutions
(1) George Washington University Hospital, Washington, DC, (2) El Camino Hospital, Mountain View, CA, (3) El Camino Health, Mountain View, CA, (4) N/A, N/A, (5) N/A, San Francisco, (6) Ohio State Wexner Medical Center, Columbus, OH, (7) N/A, United States

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