Frozen Elephant Trunk in Aortic Arch Disease: Different Devices for Different Pathologies

Hybrid Treatment of Complex Diseases of the Aortic Arch and Descending Thoracic Aorta by Frozen Elephant Trunk Technique

The surgical management of acute and chronic complex diseases involving the aortic arch and the descending thoracic aorta remains challenging. Hybrid procedures associating total open arch replacement and stent-grafting of the proximal descending aorta were developed to allow a potential single-stage treatment, promote remodeling of the downstream aorta, and facilitate a potential second-stage thoracic endovascular aortic repair by providing an ideal landing zone. While these approaches initially used various homemade combinations of available conventional prostheses and stent-grafts, the so-called frozen elephant trunk technique emerged with the development of several custom-made hybrid prostheses. The aim of this study was to review the contemporary outcomes of this technique in the management of complex aortic diseases, with a special focus on procedural planning, organ protection and monitoring, refinements in surgical techniques, and long-term follow-up.

Zone proximalization in frozen elephant trunk: what is the optimal zone for open intervention? A systematic review and meta-analysis

INTRODUCTION

The treatment of complex aortic lesions involving the ascending, arch, and proximal descending aorta, remains challenging for surgeons despite the evolution of surgical techniques and aortic prostheses over decades. The frozen elephant trunk (FET) approach offers a one-stage repair of this entity of aortic pathologies. The main scope of this systematic review and meta-analysis is to evaluate the clinical outcomes and effectiveness of FET.

EVIDENCE ACQUISITION

In a systematic review, multiple electronic databases including EMBASE, Scopus, and PubMed/MEDLINE were searched from inception to June 2021 to identify relevant studies reporting on outcomes of total arch replacement (TAR) with FET.

EVIDENCE SYNTHESIS

Eighty-five studies met inclusion criteria, encompassing 10960 patients. Meta-analysis was conducted using the R-studio (RStudio, Boston, MA, USA) and STATA software (StataCorp LLC, College Station, TX, USA). The pooled in-hospital mortality rate was 7% (95% CI 0.05-0.09; I²=76%) and 12% for renal failure (95% CI 0.09-0.15; I²=88%), while the rates for paraplegia and cerebrovascular accidents were 3% (95% CI 0.02-0.04; I²=0%) and 6% (95% CI 0.05-0.08; I²=73%), respectively. Lower heterogeneity was attained after the stratification by the aortic pathologies, except for the renal failure. The distal anastomosis of the stent in zone 2 was significantly correlated with a lower renal failure development compared to zone 3 (odds ratio 0.52; 95% CI 0.33-0.82; P=0.069; I²=0%).

CONCLUSIONS

Our results indicate that the morbidities and mortality following TAR with FET were acceptable. We also associated the distal anastomosis in zone 2 with fewer renal failure development compared to that in zone 3.

“Why is frozen elephant trunk better than classical elephant trunk?”

The treatment of complex aortic arch disease, in chronic or acute setting, has always represented a fascinating challenge for the heart surgeon also because, often, the involvement of the aortic arch is associated with a simultaneous involvement of the ascending aorta and of the proximal portion of the descending thoracic aorta. In recent years, there have been many surgical and/or endovascular techniques and approaches in a single step or multiple steps proposed with the aim of treating and simplifying these complex conditions. The first procedure available for this purpose was the conventional elephant trunk technique, proposed by the German surgeon Hans Borst, back in 1983. In the following years, the technique has undergone modifications, up to what is nowadays considered its most modern evolution, represented by the frozen elephant trunk which allows managing the proximal descending thoracic aorta using the antegrade release of a self-expandable stent graft. In this review article, we try to analyze the advantages and drawbacks of both techniques from clinical and practical points of view.

BioGlue and E-Vita Open NEO graft oozing: Long-term solution or band aid?

BACKGROUND

The introduction of the single-step total arch replacement (TAR) with frozen elephant trunk (FET) has revolutionised the field of aortic surgery. TAR is indicated when the aortic arch is involved in aortic pathologies such as Type A aortic dissection and thoracic aortic aneurysms. Several FET devices are available commercially for global use, and example is the E-Vita Open NEO hybrid prosthesis (HP) developed by CryoLife-JOTEC. Unlike other FET devices available, this HP in particular features a design that puts it at a disadvantage as it does not incorporate gelatine or collagen in its structure, which makes it permeable to blood. Several studies have reported incidence of post-anastomotic blood oozing through the E-Vita Open NEO right after weaning from cardiopulmonary bypass.

AIMS

This commentary aims to discuss the recent study by Tan et al. which investigated E-Vita NEO device oozing as well as the implications of using BioGlue to overcome this serious complications.

METHODS

We carried out a literature search on multiple electronic databases including PUBMED and Scopus in order to collate research evidence on E-Vita NEO device oozing, BioGlue health risks, and other commercially available and globally used FET devices such as Thoraflex Hybrid.

RESULTS

It is proven fact that the E-Vita NEO excessively oozes blood, and while BioGlue is a safe and effective agent when used in small amounts, the amount needed to coat the E-Vita Open NEO and achieve haemostasis exceeds this by a wide margin which poses patients to great potential health risks. The Thoraflex Hybrid Prosthesis developed by Terumo Aortic is a commercially available and globally used FET device with long-standing favourable outcomes.

DISCUSSION

Tan et al. recently conducted an interesting study which proved that the E-Vita NEO HP does excessively ooze blood and tackled the issue of pre-emptive BioGlue use to tackle this complication as suggested by Ho et al. This leads on to the main question, is the use of BioGlue with E-Vita Open NEO to overcome oozing a long-term sustainable solution or is it merely a band aid?

CONCLUSION

In the face of fierce commercial competition, the choice of design and material of the E-Vita Open NEO HP would benefit from reconsideration.