The frozen elephant trunk technique: impact of proximalization and the four-sites perfusion technique

First-in-men experience with a novel frozen elephant trunk prosthesis featuring an endovascular side branch for left subclavian artery connection

OBJECTIVES

The objective of this study was to enhance the efficiency of aortic arch replacement through the development of a novel frozen elephant trunk (FET) prosthesis with an endovascular side branch for left subclavian artery (LSA) connection. After successful pre-clinical testing, the feasibility and safety of implementing this innovative prosthesis in human subjects were investigated.

METHODS

Between September 2020 and September 2021, 4 patients (mean age 67) with conditions such as penetrating ulcer, non A-non B aortic dissection and chronic arch aneurysm underwent surgery utilizing the customized device. Surgeries were performed under high moderate hypothermia (27°C), employing bilateral selective antegrade cerebral perfusion (SACP) and distal aortic perfusion. Anastomosis of the FET prosthesis with the aortic arch occurred in zone 1, followed by separate reimplantation of the left common carotid artery and the brachiocephalic artery.

RESULTS

All patients were discharged in good clinical condition. The mean aortic cross-clamp, antegrade selective cerebral perfusion and distal aortic perfusion times were 111, 71 and 31 min, respectively. Endovascular extension of the side branch for the LSA was required in all cases to prevent endoleak formation. One patient received a stent graft extension at the end of the operation, while 2 others underwent the procedure during their hospital stay. One patient was diagnosed with an endoleak at the first follow-up after 3 months, and endoleak sealing was achieved via the brachial artery with an extension stent graft.

CONCLUSIONS

Preliminary clinical outcomes suggest that the newly designed FET prosthesis shows promise in simplifying total arch replacement. These initial findings provide a foundation for planned clinical studies to further assess the effectiveness of this modified surgical hybrid graft, with particular attention to the length and diameter of the LSA sidearm.

Surgical Strategies in Reoperation of the Proximal Aorta and Arch for Patients with Previous Frozen Elephant Trunk

Background: The frozen elephant trunk (FET) technique is increasingly utilized for aortic arch replacement in cases of aortic dissections and aneurysms. This rise in usage has led to more patients needing redo aortic surgeries due to progression of existing conditions, FET-related complications, or new valvular/coronary diseases. This article aims to evaluate surgical techniques to minimize risks during these reoperations, including a case study of a complex redo surgery. Methods: A comprehensive examination of surgical strategies was conducted, focusing on preoperative preparation, cannulation site identification, cerebral and cardiac protective measures, and pitfalls to avoid. The importance of adapting to the modified anatomical landscape post-FET is emphasized. A detailed case study of a patient undergoing complex redo FET surgery is included. Results: The article identified key surgical strategies for reoperation in patients with prior FET, highlighting the importance of meticulous preoperative planning and execution. Techniques to minimize risks include detailed imaging for planning, strategic cannulation for optimal perfusion, multidisciplinary approaches as well as careful fail-safe measures. The case study demonstrates the practical application of these strategies in a high-risk scenario. The evidence underscores the necessity for individualized patient management and the development of standardized protocols. Conclusions: The FET technique, while effective for initial aortic arch repairs, often necessitates complex reoperations. Adopting advanced surgical strategies and multidisciplinary planning can significantly mitigate risks associated with these procedures. Future research should focus on refining these techniques and establishing standardized protocols to improve patient outcomes.

Open aortic arch repair without circulatory arrest by frozen elephant trunk in Ishimaru zone 0

BACKGROUND

Open arch surgery is technically demanding for the surgeon and surgically and biologically invasive for the patient, requiring a variably long period of hypothermic circulatory arrest.

CASE PRESENTATION

Here we present a case of an elderly patient with chronic renal failure and multiple splanchnic artery disease successfully treated for a rupturing pseudoaneurysm of the aortic arch with a technique that we developed for particularly frail patients. The procedure includes: triple supra-aortic vessel perfusion; distal thoracic aorta antegrade perfusion; balloon endo-clamping of the descending aorta; and anastomosis of an off-the-shelf hybrid arch prosthesis in Ishimaru zone 0. These maneuvers allowed to maintain an extracorporeal circulation in the phase of distal anastomosis, instead of a period of circulatory arrest, employing just mild hypothermia: technical details are depicted and discussed also in comparison with other methods proposed in the literature.

CONCLUSIONS

Being able to take advantage of both open surgery advancements and endovascular methods is the key to cardiovascular surgery success today in front of complex pathologies of the aorta: increasing safety and reducing invasiveness of therapeutic options may progressively extend surgical candidacy to the frailest patients.

Trilateral versus Bilateral Antegrade Cerebral Perfusion in Frozen Elephant Trunk: A Propensity Score Analysis

OBJECTIVE

 Spinal cord injury (SCI) with subsequent paraplegia and/or stroke after arch repair with frozen elephant trunk (FET) remain the most devastating complications. In this study, we aim to examine the impact of different cerebral perfusion strategies on the neurological outcome comparing bilateral antegrade cerebral perfusion (bACP) and trilateral antegrade cerebral perfusion (tACP).

METHODS

 Between 2009 and 2021, 88 patients underwent total arch replacement using a hybrid prosthesis in FET technique for acute (40.4%) and chronic (59.6%) aortic pathologies. After excluding 14 patients who underwent FET with unilateral ACP the remaining 74 patients were divided into two groups. Propensity score matching was performed based on pre- and perioperative patient characteristics resulting in 22 patients in each group. The primary endpoint was a combination of major cerebral event and SCI. Secondary end point was all-cause mortality.

RESULTS

 Major cerebral events occurred in 9% of the patients in bACP versus 13.6% in tACP group (p = 0.63). No postoperative SCI was observed in patients with bACP and only one patient suffered SCI with tACP (p = 0.31). There was no significant difference in 30-day mortality between the two groups (22.7% in bACP vs. 13.6% in tACP; p = 0.43).

CONCLUSION

 In patients undergoing total aortic arch repair using FET technique, both perfusion strategies (bilateral and trilateral ACP) are safe and effective. The rates of neurological complications as well as mortalities are acceptably low in both groups. Further studies with larger patient cohorts are warranted.

Standardized in vitro bleeding tests in a non-coated novel hybrid prosthesis for frozen elephant trunk demonstrates minimal oozing during full heparinization, supported by clinical data

Introduction

Recent reports have questioned the blood impermeability of the novel frozen elephant trunk (FET) device E-vita Open NEO© (EO-NEO). Therefore, standardized in vitro bleeding tests using porcine heparinized blood were performed, as well as stress testing on the blood tightness of the collar suture line, to investigate this observation.

Material and methods

EO-NEO prostheses were examined in vitro for blood permeability in three test series. Initially, antegrade perfusion with heparinized porcine blood [activated clotting time (ACT) of 500 s, with a 60 min duration] was performed, followed by ante/retrograde testing via the EO-NEO side port. Testing of the collar suture line under a tension of 10 Newton (N) within a suspension device (blood pressure 120 mmHg, ACT of 560 s, 1 min duration) was carried out with the suture material force fiber white (FFWs) yarn, using standard fixation (5 stitches/cm), FFWh yarn in hemostatic fixation (15 stitches/cm), and flow weave yarn (FWYh).

Results

Blood permeability testing of EO-NEO through the prosthetic lumen or via the side port demonstrated minor leakage without statistical difference between the standard and hemostatic suture lines or suture materials used, or positioning on the crimped or tapered portion (p > 0.05). The specific collar anastomosis testing demonstrated leakage volumes of 140 ml/min for FFWs vs. 16 ml/min for FFWh (p = 0.02), vs. 9 ml/min with the FWYh (p = 0.01).

Conclusion

Different blood leakage tests showed minimal oozing and no difference in blood loss through the fabric and different collar suture lines, but unphysiological pressurized retrograde perfusion of the collar region showed significantly less leakage using FWYh and FFWh, prompting production modification of EO-NEO. Clinical results confirmed low blood loss using this novel FET device.

Treatment of right-sided aortic arch aneurysms with aberrant left subclavian artery with Kommerell's diverticulum using the frozen elephant trunk technique

OBJECTIVES

The ideal treatment for aneuryms of aberrant left subclavian arteries with Kommerell's diverticulum arising from right aortic arches remains open.

METHODS

Between January 2015 and December 2020, 5 patients with aneurysms from a right-sided aortic arch with aberrant left subclavian artery and Kommerell's diverticulum underwent repair by using the frozen elephant trunk technique in 3 aortic centres. Patients' characteristics were retrospectively reviewed and the surgical procedure and outcomes are presented.

RESULTS

The median age of the 2 male and 3 female patients was 59 (range from 49 to 63) years. The median operative times were as follows: surgery 405 min (range from 335 to 534), cardiopulmonary bypass time 244 min (range from 208 to 280) and aortic clamp time 120 min (from 71 to 184). The mean core temperature was 25.94°C (from 24 to 28). The intensive care unit stay was 4 days (range from 1 to 8) and the in-hospital stay 21 days (from 16 to 34). All patients were discharged and we observed no stroke or spinal cord ischaemia postoperatively. During the median follow-up time of 1003 days (range from 450 to 2306), 3 patients required subsequent thoracic endovascular distal stent graft extension.

CONCLUSIONS

The frozen elephant trunk technique is a good treatment option for patients with aneuryms of an aberrant left subclavian artery with Kommerell's diverticulum arising from right aortic arches. Secondary stent graft extension is a frequently needed component of the treatment concept.

The Thoraflex hybrid approach using a zone 0 proximal landing site for first-stage elective treatment of a thoracoabdominal aneurysm

A 67-year-old woman was referred to the cardiothoracic outpatient clinic with a long-standing asymptomatic type 2 thoracoabdominal aneurysm. Her CT aorta showed extensive disease in the distal arch with no safe landing zone for total endovascular aneurysm repair (TEVAR). An acute bend preceding the descending aorta also made using a conventional elephant trunk challenging. A multi-disciplinary team decision was made to perform an aortic arch replacement using a frozen elephant trunk at zone 0. Utilizing a zone 0 approach in an elective case can result in quicker organ perfusion and successful TEVAR if necessary.

Extra-anatomical left common carotid and subclavian artery bypass followed by aortic arch replacement with frozen elephant trunk

BACKGROUND

Total arch replacement (TAR) using a frozen elephant trunk (FET) allows for simultaneous treatment of the aortic arch and descending aortic pathology via median sternotomy. In addition, an extra-anatomical bypass performed between the left common carotid artery (CCA) and subclavian artery (SCA) prior to TAR allowed further proximalisation of the FET prosthesis, facilitated distal anastomosis of the TAR and spared the demanding left subclavian artery (LSA) anastomosis in the deep thorax. We investigated the efficacy of this debranching-first technique, followed by TAR using a frozen elephant trunk, as a two-stage operation for extensive thoracic aortic aneurysms in high-risk patients.

METHODS

Forty-nine consecutive patients with diffuse degenerative aneurysms from the aortic arch to the descending aorta or chronic aortic dissection who underwent left common carotid to subclavian artery bypass followed by TAR using a frozen elephant trunk and subsequent thoracic endovascular aortic repair between 2016 and 2021 were analysed. The baseline characteristics and clinical outcomes were assessed. The estimated overall survival, 5-year aortic event-free survival, and aortic reintervention rates were analysed.

RESULTS

The average European System for Cardiac Operative Risk Evaluation (EuroSCORE II) was 4.7 ± 2.5. The operative mortality rate was 4.1%, with no paraplegia events. The estimated 5-year overall survival, cumulative aortic-related mortality rates were 76.8% and 2%, respectively. The estimated 5-year overall cumulative aortic reintervention rate, including the intended intervention, was 31.3%. The estimated 5-year cumulative rate of non-intended reintervention was 4.5%.

CONCLUSIONS

The assessed technique enables a less technically demanding surgery with reasonable outcomes. The estimated 5-year aortic event-free survival and reintervention rates were acceptable, suggesting that multiple stages of alternative open and endovascular interventions, such as this technique, may reduce the morbidity and mortality rates of high-risk patients with diffuse thoracic aortic aneurysm. UMIN-CTR (University hospital Medical Information Network-Clinical Trial Registry) https://center6.umin.ac.jp/cgi-open-bin/ctr_e/index.cgi Clinical registration number: UMIN000051531.

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.

Analysing debranching techniques in Frozen Elephant Trunk procedures: a narrative literature review

Background and Objective

Since 2003, the Frozen Elephant Trunk (FET) technique has attained rising popularity for treating extensive aortic arch pathologies such as acute and chronic aortic dissection, as well as thoracic aortic aneurysm. Conventionally, the FET procedure included a complete resection of the aortic arch and, subsequently, a distal aortic anastomosis of the prosthetic part of the hybrid graft in arch zone 3. Simultaneous to the introduction of the FET technique, the traditional Elephant Trunk technique was simplified by adding debranching techniques which allows for proximalization of the distal aortic anastomosis. Nowadays, modern concepts of aortic arch surgery combine the FET technique with proximalization of the distal anastomosis in arch zone 2 or further proximal, achieved by using different debranching techniques. This review describes different debranching techniques to facilitate arch reconstruction, and aims to critically assess the outcomes and potential clinical advantages of proximalization using debranching in FET surgery.

Methods

We conducted a search using the PubMed and Google Scholar electronic databases to evaluate published outcomes of different debranching techniques. An overview of the data synthesis of 21 included studies is reported.

Key Content and Findings

Most studies report numeric, but not statistically significant improved outcomes after debranching in FET surgery for mortality, neurological complications, spinal cord injury, kidney failure, bowel ischemia and recurrent nerve palsy. Some studies report statistically significant improved results in isolated endpoints such as neurological, bowel ischemia, and recurrent nerve palsy. Most studies report debranching to be technically easier, but this is difficult to objectively assess and measure.

Conclusions

There is an improved numeric outcome of different debranching techniques with proximalization of the distal anastomosis, but without reaching statistical significance. This review shows marked heterogeneity across included studies and highlights the scarce use of existing guidelines in clinical research of open aortic arch surgery as proposed by the International Aortic Arch Surgery Study Group. Furthermore, this review demonstrates the urgent need for multicenter registries or studies to be able to compare the outcome of different surgical techniques for various aortic arch pathologies.

Case report: Multi-site perfusion strategy for type A acute aortic dissection complicated with cerebral malperfusion

Acute type A dissection presenting with cerebral malperfusion has high morbidity and mortality. Given the complexity of underlying vascular involvement, it is a challenging clinical scenario. Many of these patients are not deemed surgical candidates. If surgery is considered, it often requires complex aortic arch and neck vessel reconstruction. We present a 48-year-old male with an acute type A aortic dissection that presented with paraplegia and decreased level of consciousness. A Computed Tomography showed occlusion of both common carotid arteries. He was successfully treated with a multi-site perfusion strategy and a Hybrid Frozen Elephant Trunk graft to achieve fast restoration of the cerebral circulation and minimize brain ischemia and permanent neurological damage. From this case, we learn that aggressive arch and neck vessel reconstruction supported by multi-site perfusion could help improve mortality and neurological outcomes in selected patients.

Normothermic frozen elephant trunk: our experience and literature review

BACKGROUND AND OBJECTIVE

The frozen elephant trunk (FET) technique has undoubtable advantages in treating complex and extensive disease of the aortic arch and the thoracic descending aorta. Despite several improvements in cardiopulmonary bypass conduction and surgical strategy, operative times and the institution of systemic circulatory arrest remain the main determinants of early mortality, cerebral/spinal cord injury and visceral organs dysfunction. We have conducted this review to highlight the recent technical advances in arch and FET surgery aiming at the reduction/avoidance of systemic circulatory arrest, and their impact on early outcomes.

METHODS

A literature search (from origin to January 2022), limited to publications in English, was performed on online platforms and database (PubMed, Google, ResearchGate). After a further review of associated or similar papers, we found 4 experiences, described by 11 peer-reviewed published papers, which focused on minimising or avoiding systemic circulatory arrest during total arch replacement plus stenting of the descending thoracic aorta.

KEY CONTENT AND FINDINGS

Recent experiences reported the use of an antegrade endoaortic balloon, advanced and inflated into the stent graft, to provide an early systemic reperfusion soon after the deployment of the stented portion of the FET prosthesis and minimize the circulatory arrest time (down to a mean of 5 minutes), thus avoiding the need of moderate or deep hypothermia (mean systemic temperature 28-30 °C) while allowing a complete arch and FET repair. Our approach, based on off-pump retrograde vascular stent graft deployment in distal arch/descending thoracic aorta, and the use of a retrograde endoballoon, allows the repair of extensive aortic pathologies during uninterrupted normothermic cerebral and lower body perfusion.

CONCLUSIONS

The use of endoballoon occlusion has emerged in recent years as a safe and effective strategy to allow distal perfusion during FET repair. This technique minimizes or avoids the detrimental effects of hypothermia and systemic circulatory arrest and significantly reduces the operative times.

Single-Center Experience With the Thoraflex™ Hybrid Prosthesis: Indications, Implantation Technique and Results

Objective

The aim of this study was to evaluate the early and mid-term results after the frozen elephant trunk (FET) procedure for the treatment of complex arch and proximal descending aortic disease in a single-center institution.

Methods

From April 2015 to July 2021, 72 patients (25 women, 60.4 ± 10.3 years) underwent Thoraflex™ Hybrid implantation at our institution. The indications were thoracic aortic aneurysm (TAA) (n = 16, 22.2%), post-dissection aneurysm (n = 21, 29.2%), and acute aortic dissection (AAD) (n = 35, 48.6%). Antegrade cerebral perfusion under moderate hypothermia (28°C) was employed in all cases. Eighteen patients (25%) have already been operated due to heart or aortic disease.

Results

Overall in-hospital mortality was 12.5% (9 patients). Rates of permanent neurological dysfunction and spinal cord injury were 9.7 and 5.5%, respectively. The in-hospital mortality rate among patients operated on AAD, TAA, and post-dissection aneurysm were 8.6, 6.2, and 23.8%, respectively. At a mean follow-up of 26 ± 20 months, mortality was 9.7%. Furthermore, 23 patients (31.9%) required a subsequent procedure in distal aorta: endovascular stentgraft extension in 19 patients (26.4%) and open aortic surgery in 4 patients (5.5%). The mid-term survival of patients with type A aortic dissection was 97%.

Conclusions

Our experience with the Thoraflex Hybrid prosthesis demonstrates its surgical applicability for different types of aortic pathologies with promising outcomes during early and midterm follow-up. Our technique and perioperative management lead to comparable or even superior neurological outcomes and mortality in urgent cases considering other high-volume centers.

Partial aortic arch replacement without circulatory arrest: A case study

Hypothermic circulatory arrest is commonly used during aortic arch surgery. However, it is associated with high risk of visceral organ and lower limb ischemia. There may be advantages to reduction duration of hypothermic circulatory arrest to prevent ischemic complications. We present a case of partial aortic arch replacement without use of hypothermic circulatory arrest.

NEO E-vita—NEO era!

In this review article, the history of the first commercially available thoracic aortic hybrid graft, the E-vita Open, later modified to the blood-impermeable E-vita Open Plus, is reported from its beginning in 2005 until its newest variation, the E-vita Open NEO, European conformity (CE) marked in 2020. Besides the background of its design and clinical experience in Essen, concomitant evolutionary steps in surgery as well as in strategic approaches like the hybrid operating room concept are displayed, finally leading to a well-rounded surgical package with a device that can be applied in all elective as well as emergency situations with complex arch involving aortic pathologies. With the E-vita Open NEO, now, surgery has been facilitated to convenient anastomosing in any of the arch zones, with the opportunity to use the island technique with a straight graft variation as well as individual head vessel anastomosing with either a trifurcated graft for zone 0 or the branched graft for zone 2 or 3 implantation. With its proven long-term stability, the surgical armamentarium to cope with complex multisegmental thoracic aortic pathologies has been significantly improved.