Aortic Proximalisation -- Zone 0 vs. Zone 2. A Concept or True Challenge?

Abstract

Background Use of the Frozen Elephant Trunk (FET) device to manage complex surgical pathologies of the aorta (e.g. acute Type A aortic dissection) has gained popularity since its introduction in the early 2000s. Though the distal anastomosis was traditionally performed at Zone 3 (Z-3-FET), preference gradually shifted towards Zone 2 (Z-2-FET) in favour of improved surgical access and outcomes. This review seeks to elucidate whether proximalisation of arch repair to Zone 0 (Z-0-FET) would further improve postoperative outcomes. Methods We performed a review of available literature to evaluate the comparative efficacies of Z-2-FET versus Z-0-FET, in terms of surgical technique, clinical outcomes, and incidence of adverse events. Results Z-0-FET seems to be associated with a more accessible surgical approach, and shorter cardiopulmonary bypass, antegrade cerebral perfusion, and cardioplegia durations than Z-2-FET. Further, Z-0-FET is could potentially be associated with a lower incidence of neurological, renal, and recurrent laryngeal nerve injury, as well as mortality and reintervention rates than Z-2-FET. This said, Z-0-FET is itself associated with significant challenges, and efficacy in terms of postoperative true lumen integrity and false lumen thrombosis is mixed. Conclusion Current literature seems to suggest that Z-0-FET procedures are more straightforward and associated with lower rates of certain adverse events, however, the majority of data reviewed is retrospective. This review therefore recommends prospective research into the comparative strengths and limitations of Z-0-FET and Z-2-FET to better substantiate whether proximalisation of arch repair represents a concept, or a true challenge to advance surgical intervention for arch pathologies.

What Is the Long-Term Clinical Efficacy of the Thoraflex™ Hybrid Prosthesis for Aortic Arch Repair?

“…Furthermore, the inclusion of the fourth arch branch (a feature unique to Thoraflex Hybrid™) allows lower body perfusion to be restored immediately after distal anastomosis. This may greatly reduce the duration for which the viscera, spinal cord, and lower limbs are exposed to circulatory arrest, and thereby mitigate the risk of ischaemic complications ( 8 , 9 ).…”

“…and spinal cord manifestations (paraplegia, spinal deficit etc.) may result ( 9 ). The pathogenesis of aortic surgery-induced neurological injury is varied and complex; attributing neurological complications to the chosen aortic device, cerebral perfusion technique, device sizing, CPB/HCA duration, or device positioning is therefore challenging.…”

“…Though it is challenging to attribute the discrepancy in rates of neurological complications to aortic device alone, it is worth noting that Thoraflex Hybrid's™ unique design—which includes a 4th arch branch to enable early lower body perfusion after distal anastomosis—may help to reduce the risk of spinal cord (and end-organ) ischaemia by reducing the duration of HCA needed ( 8 , 9 ). Indeed, HCA duration (as well as minimum core temperature and stent graft length) have been identified as predictors of SCI risk, and interestingly, Berger et al multicentre investigation reported at patients implanted with Thoraflex Hybrid™ underwent substantially shorter HCA durations than those treated with E-Vita™ Open (51 min [41–59], vs. 60 min [51–69], P = 0.007) ( 9 , 16 ). Shrestha et al highlight that their patients implanted with Thoraflex Hybrid™ underwent HCA for a median of 47 min (36–61) ( 7 ).…”

Favorable neurological outcomes in thoracic endovascular aortic repair with RELAY™ branched—An international perspective

“…Unsurprisingly, given the invasiveness of surgical aortic arch repair, which necessitates cardiopulmonary bypass (CPB) and hypothermic circulatory arrest (HCA), many patients are declared unfit for surgical intervention 2 . Though the frozen elephant trunk (FET) technique for arch reconstruction provides a hybrid open‐endovascular option for aortic arch repair and has been associated with improved perioperative outcomes relative to techniques such as conventional elephant trunk (cET), it remains highly invasive and debilitating complications such as stroke, bleeding, and visceral ischemia continue to be omnipresent risks 3,4 . The enduringly high turn‐down rate (up to 40%) for open surgical aortic arch reconstruction exemplifies this growing issue 5 …”

“…2 Though the frozen elephant trunk (FET) technique for arch reconstruction provides a hybrid open-endovascular option for aortic arch repair and has been associated with improved perioperative outcomes relative to techniques such as conventional elephant trunk (cET), it remains highly invasive and debilitating complications such as stroke, bleeding, and visceral ischemia continue to be omnipresent risks. 3,4 The enduringly high turn-down rate (up to 40%) for open surgical aortic arch reconstruction exemplifies this growing issue. 5 There is therefore a need for a less invasive approach to the management of aortic arch pathologies, particularly in patients for whom the risks of surgical intervention may outweigh the benefits thereof.…”