This is a prospective, randomized, non-inferiority clinical trial designed to compare the efficacy and safety of two surgical strategies for acute type A aortic intramural hematoma (TAIMH): (1) ascending aorta replacement or ascending aorta plus hemiarch replacement (AAR/AAR+HAR), and (2) ascending aorta replacement with total arch replacement and frozen elephant trunk implantation (AAR+TAR+FET). Patients will be enrolled based on CTA confirmation of a completely thrombosed false lumen in the ascending aorta and aortic arch. Eligible participants will be randomized in a 1:1 ratio to either group. The primary endpoint is the rate of reintervention on the aortic arch or descending aorta from 6 to 12 months after surgery. Secondary endpoints include circulatory arrest time, aortic cross-clamp time, major adverse cardiovascular events, other perioperative complications, and total hospitalization cost. A total of 400 participants will be enrolled.

This is a prospective, randomized, controlled, non-inferiority study comparing two surgical strategies for acute type A aortic intramural hematoma (TAIMH). Patients with acute TAIMH will be screened and enrolled based on CTA confirmation of a completely thrombosed false lumen in the ascending aorta and aortic arch. Participants will be randomly assigned in a 1:1 ratio to receive either AAR/AAR+HAR or AAR+TAR+FET, with 200 participants in each group. Postoperative CTA will be performed before discharge, and follow-up CTA will be performed at 6 to 12 months after surgery.

The surgical procedure will be performed through a median sternotomy or upper partial sternotomy. Cardiopulmonary bypass will be established through right axillary/femoral arterial and bicaval venous cannulation, or femoral arteriovenous cannulation and superior vena cava cannulation. Left ventricular venting will be achieved via the right superior pulmonary vein. Antegrade HTK or cold blood cardioplegia will be administered under direct vision and repeated every 30 minutes. During circulatory arrest, bilateral selective antegrade cerebral perfusion will be provided via the right axillary artery and left common carotid artery.

The primary endpoint is the rate of reintervention on the aortic arch or descending aorta from 6 to 12 months after surgery. Secondary endpoints include circulatory arrest time, aortic cross-clamp time, major adverse cardiovascular events, other perioperative complications, and total hospitalization cost. The trial is designed to test whether the less extensive AAR/AAR+HAR strategy is non-inferior to AAR+TAR+FET with respect to the primary endpoint, while potentially offering advantages in operative burden, perioperative safety, and hospitalization cost.

Inclusion Criteria:

1. Age ≥ 18 years and ≤ 80 years.
2. Diagnosis of type A aortic intramural hematoma (TAIMH).
3. Ability to understand the study procedure and provide written informed consent.

Exclusion Criteria:

1. Preoperative CTA shows an open or partially thrombosed (mixed) false lumen in the ascending aorta or arch.
2. Primary tear located on the greater curvature of the aortic arch, necessitating total arch replacement.
3. Planned concomitant major cardiac surgery (e.g., CABG, valve replacement, atrial fibrillation ablation).
4. Previous history of aortic arch or distal aortic surgery.
5. Severe peripheral vascular disease or cerebrovascular anatomy abnormality.
6. Active systemic infection, malignancy, severe hepatic or renal dysfunction, or other major comorbidities with life expectancy < 1 year or deemed unfit for complex cardiovascular surgery.
7. Pregnancy or lactation.
8. Severe psychiatric or cognitive disorders affecting compliance or follow-up.

De-identified individual participant data (IPD) that underlie the results reported in the published article will be shared. This includes baseline demographic data, clinical characteristics, operative details, and all primary and secondary outcome measures collected during the study. Additionally, the study protocol, statistical analysis plan (SAP), and clinical study report (CSR) will be made available to provide context for the data.

Beginning 6 months after the publication of the primary results and for a period of 5 years.

Researchers with a methodologically sound proposal, approved by an independent review committee. Data requestors will be required to sign a data access agreement.

Participant Blinding: The patient will not be informed of whether they received a Ascending Aorta/Hemiarch or Total Arch Replacement procedure. This is maintained through consistent post-operative communication that does not disclose the specific surgical technique.

Outcome Assessor Blinding: Members of the independent clinical event adjudication/imaging review team who assess reintervention-related outcomes are blinded to treatment allocation.

Care Provider (Surgeon) Blinding: The operating surgeons cannot be blinded due to the nature of the surgical interventions.