Jacob Ede- Institutionen för kliniska vetenskaper, Lund

Title: Neurological injury in acute type A aortic dissection

Main supervisor: Igor Zindovic

Reviewers: Johan Nilsson, Arash Mokhtari

Abstract

Background

Acute type A Aortic dissection is a life-threatening disease, with up to 50% of patients dying before reaching the hospital. Even when surgical repair is performed, 15-20% of patients do not survive the early postoperative period. In patients with acute type A aortic dissection, 10-20% present with neurological symptoms, and after surgery 10-15% have symptom of stroke and 3-9% are rendered comatose. In patients with neurological injury following surgical repair, mortality and morbidity is increased.

Research questions

• Does air embolism account for neurological injury following surgical repair, and can it be prevented using carbon dioxide flooding in the surgical field?
• What are the radiological properties of neurological injury following ATAAD surgery?
• Does retrograde cerebral perfusion protect against neurological injury?
• Which of the patients who present with neurological symptoms, suffer a permanent neurological injury after ATAAD repair?

Preliminary results

The first article was a methods and objectives manuscript describing the CARTA trial. 

In our second study we showed that radiological features of cerebral injury may be as important as clinical manifestations in understanding the pathophysiology of neurological injuries following ATAAD repair. Embolic lesions more often occurred in the right hemisphere. Basilar artery obstruction and watershed lesions were associated with postoperative coma. Preoperative cerebral malperfusion predisposes postoperative neurological injury.

The third study (manuscript) showed that retrograde cerebral perfusion reduces the risk of clinical neurological injury, embolic lesions, and watershed lesions compared to hypothermic circulatory arrest only. The results suggest that the effect of retrograde cerebral perfusion may partially be the consequence of washout of air and other embolic material, while the reduced risk of watershed lesions may be related to retrograde cerebral perfusion having some metabolic effect on the cerebral parenchyma.

Significance

We have provided a better understanding of the pathophysiology causing neurological injuries following ATAAD, 

Large international databases show that up to 30% of repairs are performed without selective cerebral perfusion and our study may further encourage the use of RCP for reducing neurological injuries following ATAAD repair.

If carbon dioxide flooding would prove to reduce neurological injury it would be widely implemented by cardiothoracic surgeons. 

Published studies

1. Ede J, Teurneau-Hermansson K, Moseby-Knappe M, Ramgren B, Bjursten H, Ederoth P, Larsson M, Mattsson-Carlgren N, Sjögren J, Wierup P, Nozohoor S, Zindovic I. Carbon dioxide flooding to reduce postoperative neurological injury following surgery for acute type A aortic dissection: a prospective, randomised, blinded, controlled clinical trial, CARTA study protocol - objectives and design. BMJ Open. 2023 May 25;13(5):e063837.
   
    
2. Ede J, Teurneau-Hermansson K, Ramgren B, Moseby-Knappe M, Larsson M, Sjögren J, Wierup P, Nozohoor S, Zindovic I. Radiological properties of neurological injury following acute type A aortic dissection repair. JTCVS Open. 2023 Jun 16;15:38-60.

Manuscript under review:

1. Ede J, Teurneau-Hermansson K, , Ramgren B, Moseby-Knappe M Åström DO, Larsson M, Sjögren J, Wierup P, Nozohoor S, Zindovic I. Retrograde cerebral perfusion reduces embolic and watershed lesions after acute type A aortic dissection repair with hypothermic circulatory arrest