Karl Teurneau-Hermansson- Institutionen för kliniska vetenskaper, Lund

Title: Prognostic considerations in Acute type A aortic dissection

Main supervisor: Igor Zindovic

Reviewers: Torsten Malm, Sigurdur Ragnarsson 

Abstract

Background

Acute type A aortic dissection (ATAAD) is a highly emergent condition with an incidence of 2-16 cases per 100,000 patient years. The gold standard of care is immediate surgical repair but up to 50% of the patients die before even reaching a hospital. It has been classically accepted that the hourly mortality rate during the first 24 hours after symptom onset for patients that do not receive surgical treatment is 1-2%. 

The propagation of the false lumen in an ATAAD can cause end organ ischemia leading to symptoms that may mimic several other conditions more commonly seen in the Emergency Department (ED) such as acute coronary syndrome, stroke, and pulmonary embolism. This makes misdiagnosis a big clinical concern occurring in 16-78% of the cases. 

Even with adequate surgical treatment and intensive care mortality and morbidity remains high. The in-hospital mortality for surgically treated ATAAD is about 18%, while 10-15% suffer strokes postoperatively and 3-9% end up in postoperative coma. Studies suggest that neurological injuries account for 15% of the in-hospital mortality.

Research questions

1. Can the astrocytic biomarker S100B be used to predict neurological injuries in surgically treated ATAAD patients (study 1)?
2. What is the mortality rate in non-surgically treated ATAAD-patients (study 2)?
3. What is the frequency of misdiagnosis of ATAAD and does initial misdiagnosis cause a delay of treatment leading to increased mortality? Is it possible to identify independent predictors of misdiagnosis (study 3)?
4. Is it possible to use readily available biomarkers, primarily D-dimer and Fibrinogen, to predict ATAAD in patients at the ED (study 4)?

Preliminary results

Study 1 demonstrated that S100B 24 hours after surgery was a strong independent predictor for neurological injury with an OR of 4.71 in multivariable logistic regression.

Study 2 showed an hourly mortality rate of 2.6% in non-surgically treated ATAAD during the first 24 hours after symptom onset as compared to the previously accepted 1-2%.

Significance

Although rare, ATAAD remain a clinical dilemma as the condition is often misdiagnosed but require swift management and immediate surgical treatment to avoid excess mortality and morbidity. 

Published studies

Teurneau-Hermansson K, Ede J, Larsson M, Moseby-Knappe M, Bjursten H, Nozohoor S, Sjögren J, Zindovic I. S100B predicts neurological injury and 30-day mortality following surgery for acute type A aortic dissection: an observational cohort study. J Cardiothorac Surg. 2023 Feb 6;18(1):62. doi: 10.1186/s13019-023-02151-2.