The frozen elephant trunk (FET) technique, introduced in 1996 as an evolution of the classical elephant trunk approach, is a therapeutic alternative for complex aortic arch pathology. This intricate surgical method involves replacing the aortic arch and reimplanting the supra-aortic branches into the FET prosthesis. Continuous improvements in both the prosthesis design and surgical technique have led to widespread use and favorable postoperative outcomes. Nevertheless, one of the many challenges surgeons face during the implantation of these hybrid prostheses is the anastomosis of the left subclavian artery (LSA). Depending on its origin from the aortic arch and patient anatomy, this reimplantation can be technically demanding and may increase the risk of neurological complications due to prolonged cardiopulmonary bypass and selective cerebral perfusion times. This preliminary report highlights their experience with a novel prosthesis (E-vita Open NEO-LSA®, Jotec®) designed to enable fully endovascular LSA management alongside FET implantation, aiming to address this challenge. 

This prospective observational study, conducted from 2020 to 2021, included four patients diagnosed with aortic arch and proximal descending aorta aneurysms or dissections, with a mean follow-up of 35 months. Exclusion criteria encompassed LSA anomalies (aneurysms, dissections, and kinking), separate vertebral artery origin from the arch, hemodynamic instability, and cardiac or renal dysfunction. Outcomes assessed included hospital mortality, stroke, paraplegia, paraparesis, and the need for permanent dialysis (<90 days). 

All four patients (two women) underwent implantation of the custom-made hybrid prosthesis. Diagnoses included one case of penetrating aortic ulcer, one case of subacute non-A non-B dissection, and two cases of aortic arch and proximal descending aorta aneurysms. Two patients required coronary artery bypass grafting to the left anterior descending artery. Mean cardiopulmonary bypass and antegrade cerebral perfusion times were 195.75 ± 24 minutes and 111 ± 10 minutes, respectively. All patients were extubated within 48 hours, had a mean ICU stay of 4.8 days, and were discharged without major complications after an average of 25.6 days. Despite the prosthesis customization, all cases required endovascular extension of the LSA branch due to endoleaks. The main procedural complication was a brachial artery pseudoaneurysm in one patient, secondary to percutaneous LSA access for endoleak resolution using telescopic stent grafting. Over a mean follow-up of 35 months, patients maintained good health, with significant aneurysm reduction in two cases and false lumen occlusion in the dissection case. 

COMMENTARY:

The FET technique for total aortic arch replacement is a widely accepted alternative recommended in clinical guidelines for acute and chronic aortic conditions. However, it has faced criticism for prolonged cardiopulmonary bypass and circulatory arrest times, as well as higher rates of neurological complications. Continuous innovations aim to optimize this technique. This initial study seeks to demonstrate the feasibility of a novel prosthesis for the FET technique, potentially simplifying total aortic arch replacement by proximalizing the distal anastomosis to zone 2 and enabling endovascular LSA management through a lateral stented branch tailored to the patient. By reducing the number of anastomoses—particularly the LSA, one of the most complex—the technique could shorten hypothermic circulatory arrest times, avoiding open LSA anastomosis, which can be challenging when located distally or posteriorly. 

In this small cohort, all patients were discharged in good clinical condition without immediate complications and demonstrated favorable postoperative recovery. Additionally, over a 35-month mean follow-up, patients maintained good clinical outcomes with positive aortic remodeling results. However, the high frequency of LSA branch endoleaks and the need for additional procedures underscore a prosthesis design limitation in its early clinical use, requiring further refinement. 

The custom-made E-vita Open NEO-LSA® prosthesis appears to be a safe and viable option for selected indications. Nevertheless, the high rate of endoleaks and the necessity for reinterventions highlight the importance of larger studies to evaluate long-term clinical outcomes and potential design modifications. Comparative studies with other techniques would also be valuable to assess whether it offers additional clinical benefits over the conventional FET approach. The results are encouraging regarding short- and medium-term clinical outcomes with this device. However, the high rate of reinterventions for endoleaks and the small sample size necessitate further research before considering it a standard treatment or replacing devices with more established clinical experience. 

REFERENCE:

Folkmann S, Arnold Z, Geisler D, Lenz V, Miosga D, Harrer M et al. First-in-men experience with a novel frozen elephant trunk prosthesis featuring an endovascular side branch for left subclavian artery connection. Eur J Cardiothorac Surg. 2024 Aug 2;66(2):ezae302. doi: 10.1093/ejcts/ezae302.