Total Arch Replacement With Frozen Elephant Trunk Versus Hemiarch Replacement in the Management of Acute Type A Aortic Dissection

Acute Type A aortic dissection (ATAAD) and its complications are life-threatening conditions that cause more than 1400 hospital admissions and 300 deaths every year in Hong Kong and cause 172,927 deaths globally in 2019. There is an increasing trend in recent years.

Given the hyperacute presentation and complexity of the clinical manifestation with various mal-perfusion syndromes, the mortality of ATAAD remained high in all international reported registries and published series.

Conventional Hemiarch (HAR) replacement has been the gold standard procedure for ATAAD in most of cardiac surgical centers around the world because of the relative simplicity of the procedure. However, around 50-70% of patients were reported to develop distal anastomosis new entry after hemiarch procedure and for those with entry tear over aortic arch and distal mal-perfusion, hemiarch alone might not be able to solve the downstream problem. On the other hand, total arch replacement and frozen elephant trunk procedure (TARFET) is more complex, technically demanding procedure that could potentially cover/resect the arch entry tear and exclude tear over proximal descending thoracic aorta and, hence, solve the distal mal-perfusion syndrome. To date, there is no randomized control trial to answer whether HAR or TARFET procedure is superior in patients with ATAAD and entry tear is over the aortic arch or proximal descending thoracic aorta.

We plan to conduct a multi-center trial to recruit consecutive patients with ATAAD with entry tear beyond ascending aorta and randomized them, after informed consent, into either the conventional hemiarch replacement group (HAR) or total arch replacement and frozen elephant trunk (TARFET). The participating centers will collect pre- operative, intra-operative and post-operative clinical parameters for two groups of patients via REDCap system. Written informed consent, specifically allowing the use of clinical records for this randomized study, will be obtained from every patient prior to data collection. The primary outcome is the 30-day mortality of the ATAAD patients with surgically treated by HAR versus TARFET approach. The secondary outcomes are the major adverse cardiovascular and cerebral events, post-op renal replacement therapy, re-exploration for bleeding and re-intervention within 30-days.

This study will be the world's first multi-center randomized control trial in ATAAD to compare the 30-day mortality of patients treated with HAR and TARFET. It could be a guideline-changing study for the treatment of ATAAD and its impact on the surgical approach to patients suffering from ATAAD.