The sixteenth-century French surgeon Ambroise Paré remarked, “aneurysms which happen in the internal parts are incurable”,1,2 underscoring the historical challenges of managing aortic disease. Frank Nicholls’ autopsy report of King George II of England (1760) was the first to describe aortic arch dissection.3 It was not until 1944 that Crafoord and Nylin reported the first end-to-end aortic anastomosis for coarctation resection,4 and shortly after, Gross set the stage for rapid aortic repair advancements by replacing a coarctation segment with an arterial homograft.5
In 1952, Cooley and DeBakey utilised homografts for thoraco-abdominal aortic aneurysm repair,6 and by 1954 they introduced aortic dissection surgery. In 1957, homografts had been used to replace ascending aorta7 and arch.8
During the 1970s, Crawford pioneered thoraco-abdominal aneurysm repair, employing an anatomic endovascular graft-inclusion technique. His innovations improved early survival rates, achieving a remarkable 92%.9 Rather than fully resecting the aneurysm, the retained aneurysmal wall was wrapped around the replacement graft. In contemporary practice, open aortic repair remains the standard of care for the majority of patients.
Discussion
Acute type A aortic dissection (ATAAD) represents a life-threatening condition requiring urgent surgical intervention. Management strategy is determined by the location of the intimal tear, which may involve the root, ascending aorta, or arch. The Stanford classification (A and B) has been extended by the TEM system adding ‘non-A and non-B’ (Type), location of primary entry tear (E) and malperfusion (M).10
In aortic root dissection and aneurysmal dilatation syndromes, valve-sparing root reconstruction has emerged as a safe and effective alternative to traditional root replacement using valved conduit (Bentall procedure). The aortic valve is inspected for normal structure, confirming no calcifications, fenestrations, or tears. By preserving the native valve, advantages include physiological haemodynamics, reduced prosthetic valve dysfunction and infection risk. The primary challenge lies in achieving durable valve function and minimising re-intervention.
A meta-analysis of seven studies (n=858) comparing valve-sparing root replacement (n=367) with composite aortic valve graft replacement (n=491) in ATAAD revealed no difference in survival over time between the two approaches. Valve-sparing procedures were associated with a higher risk of re-operation.11 Findings are corroborated by prospective studies,12 and the Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) valve-sparing root replacement data indicate favourable long-term survival rates of 85.3% and 72.7% at five and 10 years, respectively.13 The German Aortic Root Repair Registry identified conversion factors: aortic valve/root asymmetry; aortic regurgitation severity; safety; and bicuspid valves.14 Interestingly, the long-term durability of re-implanted bicuspid valves is comparable with tricuspid valves.15
The choice of approach for valve-sparing root replacement is influenced by centre and surgeon expertise. A systematic review and meta-analysis of 21 studies comparing re-implantation (n=1,283) and remodelling (n=1,150) demonstrated comparable 30-day mortality (3% vs. 4%), stroke rates (3%), and re-operation for bleeding, with no difference in early or late aortic valve re-intervention rates. Long-term survival was similar between the two techniques.16,17
In recent developments, the Ascyrus Medical Dissection Stent (AMDS; Artivion Inc., USA) has been introduced as a treatment for DeBakey type 1 ATAAD where the entry tear is in the ascending aorta at least 1 cm proximal to the innominate artery; no arch tear; normal arch and proximal descending aortic dimensions; in a patient with no connective tissue disorder. The AMDS consists of proximal polytetrafluoroethylene cuff and distal uncovered nitinol stent. It is deployed antegrade into the arch and descending thoracic aorta during hypothermic circulatory arrest. The device serves as an alternative to hemi-arch replacement, promoting positive aortic remodelling, false lumen thrombosis, and preventing organ malperfusion.
Following conventional aortic dissection repair, the presence of intimal flap at the distal anastomosis can result in distal anastomotic new entry, leading to pressurisation of the false lumen, true lumen collapse, and complications such as increased mortality, malperfusion, aortic growth, and re-interventions. The AMDS addresses these challenges by sealing and depressurising the false lumen at the distal anastomosis, promoting true lumen expansion, restoring branch vessel perfusion, and enhancing aortic remodelling.
The international, prospective, non-randomised Dissected Aorta Repair Through Stent Implantation trial evaluated the safety and efficacy of AMDS in 47 patients undergoing emergent surgical repair for acute DeBakey type I dissections. The study reported true lumen expansion in over 95% of cases, resolution of vessel malperfusion and positive remodelling of the aortic arch in all cases, with complete obliteration or thrombosis of the false lumen in 74%. In the proximal descending thoracic aorta, positive remodelling occurred in 77% of cases, with false lumen obliteration or thrombosis in 53%. Thirty-day and one-year mortality rates were 13.0% and 19.6%, respectively, with a new stroke rate of 6.5%.18 A retrospective cohort study of ATAAD (n=57) from two German centres confirmed lower in-hospital mortality with AMDS (16%) compared with the German registry ATAAD mortality risk (22%).19 Early results from the prospective PERSEVERE (A ProspEctive, Single ARm, Multi-center Clinical InveStigation to EValuatE the Safety and Effectiveness of AMDS in the TREatment of Acute DeBakey Type I Dissection) study has shown reduced major adverse events and distal anastomostic new entry tears using AMDS for DeBakey type I dissection with pre-operative malperfusion.20
For aortic arch involvement in ATAAD, total arch replacement remains the primary surgical approach. The frozen elephant trunk (FET) prosthesis, which integrates a stent-graft for the descending aorta with a non-stented fabric graft for proximal grafting, has gained favour due to its ability to promote false lumen thrombosis and reduce the need for second-stage operations. The FET technique is indicated as an adjunct to total arch replacement in the presence of distal aortic malperfusion; complex primary and re-entry tears affecting the distal arch and proximal descending aorta (non-A, non-B); aneurysms of the distal arch or proximal descending aorta; complicated type B aortic dissection with unsuitable anatomy for endovascular option; rupture of the distal arch or descending aorta; and severe arch disruption precluding safe anastomosis.21 A systematic review of 37 studies (n=4,178) reported overall survival rates of 89.6% at one year and 85.2% at three years following FET implantation, with freedom from re-intervention rates of 93.9% and 89.3% at the same time points. Mortality, permanent neurological deficits, and spinal cord injury rates were 10.2%, 7.7%, and 6.5%, respectively.22
Long-term outcomes with FET have been encouraging. A single-centre study reported five-year survival rates of 64.1 ± 5.9% and freedom from distal aortic re-intervention at 74.2 ± 1.5% in patients with acute (n=32) and chronic (n=65) dissections. Another series from Vienna (n=187) reported a 10-year survival rate of 53.0 ± 5.5%.23,24 Despite the growing use of FET, its benefits over the conventional elephant trunk (CET) technique remain under investigation. A meta-analysis of five comparative studies (FET n=292, CET n=313) showed lower peri-operative mortality and improved one-year survival with FET, though overall or open re-intervention rates were similar. However, FET demonstrated a higher rate of endovascular re-interventions, with comparable rates of postoperative stroke, spinal cord injury, and renal failure.25
Currently, two FET devices dominate the Western market: E-vita Neo (Jotec, Hechingen, Germany) and Thoraflex™ (Vascutek, Terumo, Inchinnan, Scotland). In Asia, Sun’s tetrafurcate graft (Cronus®) is commonly utilised.26 A comparison of outcomes with Thoraflex and E-vita grafts in an Italian single-centre study (n=367) found comparable survival rates at one, two, and five years (73.2%, 70.7%, and 64.1%, respectively).27
The ExoVasc Personalised External Aortic Root Support (PEARS; Exstent Limited, UK) has recently emerged as a viable option for preventing aortic root and ascending aorta dilatation in aortopathies. A propensity score-matched comparison of PEARS and valve-sparing root replacement demonstrated similar five-year survival rates (98% vs. 99%), comparable freedom from re-intervention and preservation of valve function.28
Advances in endovascular techniques have influenced the treatment of distal aortic aneurysms. The NEXUS Aortic Arch Stent Graft System, a novel transcatheter device, has high procedural success and favourable one-year safety and performance outcomes.29 Future progress in the management of complex aortic pathologies will be closely tied to advancements in endovascular technologies.
Conflicts of interest
None declared.
Funding
None.
References
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