The Frozen Elephant Trunk Technique: European Association for Cardio-Thoracic Surgery Position and Bologna Experience

The frozen elephant trunk: an overview of hybrid prostheses

INTRODUCTION

Thoracic aortic pathologies implicating the aortic arch and the descending thoracic aorta (DTA) are primarily managed with total aortic arch replacement (TAR). This can be performed as a single-procedure hybrid fashion using the frozen elephant trunk technique (FET), which utilizes hybrid prosthesis. Nevertheless, FET presents certain challenges such as distal stent graft-induced new entry (dSINE), negative aortic remodeling, and reintervention.

AREAS COVERED

The narrative review provides an overview of the four majors FET prosthesis, highlighting their design features, mechanical properties, configurations, and variants, and evaluating their clinical outcomes reported in the literature. The leading prosthesises were compared through their mortality and survival rates, neurological outcomes, dSINE, aortic remodeling, and reintervention rates.

EXPERT OPINION

Four FET devices can be considered the main option on the global market; Thoraflex, E-Vita, Cronus, and Frozenix J Graft. Each hybrid prosthesis (HP) features unique design characteristics, resulting in varying clinical outcomes. Thoraflex and E-Vita are the most widely used and investigated HPs, whilst the use of Cronus and Frozenix is geographically confined to mainly manufacturers' countries. The rates of early mortality, stroke, SCI, dSINE, and reintervention rates were found to be comparable among the four devices, yet, Thoraflex seemed to offer the most optimal clinical profile.

Outcomes of Secondary Endovascular Aortic Repair After Frozen Elephant Trunk

OBJECTIVE

The aim of this study was to evaluate the midterm outcomes of secondary extension of frozen elephant trunk (FET) by means of thoracic endovascular aortic repair (TEVAR).

METHODS

This single-center prospective study was conducted in a tertiary aortic center on consecutive patients having undergone TEVAR with an endograft covering most of the 10 cm FET module with 2 to 4 mm oversizing. All patients were monitored by computerized tomography angiography (CTA) at sixth month and yearly thereafter.

RESULTS

From January 2015 to July 2022, among 159 patients who received FET, 30 patients (18.8%) underwent a TEVAR procedure (13 for a thoracoabdominal aneurysm, 11 for a chronic aortic dissection and 6 for an emergency procedure). All connections were successfully achieved with 2 postoperative deaths (6.6%) and 1 paraplegia (3.3%). At a median follow-up of 21 months (interquartile range [IQR], 4.2-34.7), 5 patients (25%) required a fenestrated-branched endovascular aortic repair (F-BEVAR) extension followed by 4 patients with 5 reinterventions, 3 for a Type 3 endoleak due to disconnection between FET and TEVAR endograft, and 2 unrelated to the FET for a secondary Type 1C endoleak. All reinterventions were successful, without mortality or morbidity.

CONCLUSIONS

In this series, FET connection with a TEVAR endograft was effective with low postoperative morbidity but with a risk of aortic reintervention related to disconnection between the FET and TEVAR endograft. These results suggest the need for annual CTA monitoring with no time limit in patients following connection of the FET with a TEVAR endograft.

CLINICAL IMPACT

In this series of 30 patients, midterm outcomes of secondary extension of frozen elephant trunk (FET) by thoracic endovascular repair (TEVAR) showed 3 disconnections (10%) with a Type 3 endoleak between FET and TEVAR. These findings suggest the need for annual CTA monitoring with no time limit. But so far, only a few studies provide some information after one year while the risk of disconnection increases over time and becomes a concern after 3 years. This is the new message brought by our study.

Preliminary and Intermediate-Term Results of the Novel Modification of Frozen Elephant Trunk: A Single-Center Study

Objectives: We evaluate the preliminary and intermediate-term results of Viet Duc modification of the frozen elephant trunk (FET) technique. Methods: During December 2019 and May 2023, 47 patients underwent surgery using our modification of the FET at Viet Duc University Hospital. The mean age of the patients was 56.8 years (±9.4, range 31-72). In all, 34 (72.3%) of the patients were men. Results: There were 5 (10.6%) perioperative deaths. The duration of cardiopulmonary bypass, cross-clamping, circulatory arrest, and total operation were 165 (±49.1 range 94-330), 100 (±37, range 46-205), 32.6 (±8, range 20-58), and 366 (±60.6, range 270-540) minutes, respectively. In complications, tracheotomy, temporal hemodialysis, cerebral shock, and type 1A endoleak were noted in 3 (6.4%), 4 (8.5%), 4 (8.5%), and 3 (6.4%) patients, respectively. The mean follow-up time was 25.8 months (±11.7, range 3-42). One case was dead in the follow-up period. Three patients (6.3%) had successful reoperation for type 1A endoleak, and 4 patients (8.5%) underwent a second intervention. One (2.1%) patient had a second intervention and an infrarenal abdominal aortic replacement. Conclusions: Our modification of the FET technique was feasible, effective, and safe, with good early and intermediate-term outcomes.

Aortic arch registry of type a aortic dissection (AoArch) - rationale, design and definition criteria

BACKGROUND

Type A acute aortic dissection (TAAAD) is a deadly condition that demands immediate surgery, because it involves a critically. The mortality and morbidity associated with it are significant, and it is vital that the patient's conditions and treatment strategies are fully understood to ensure the appropriate management of TAAAD. This study aims to ascertain whether hemiarch repair (HAR) versus extended arch repair (EAR) with or without descending aortic intervention results in better perioperative and late outcomes for patients with TAAAD.

METHODS

Four leading centers of cardiac surgery from two European countries have joined forces to create a groundbreaking multicenter observational registry (AoArch). This study was approved by the institutional review board (IRB 202201173). We conducted a retrospective review (NCT00591263) of our prospectively maintained database for patients who underwent operative repair of DeBakey type I or type II dissection from January 1, 2005 to March 2024 (NCT05927090). We will analyze how patient co-morbidities, referral conditions, and surgical strategies involving hemi-arch repair (HAR) and extended arch repair (EAR) impact early and late adverse events. We have developed a procedure urgency algorithm based on the severity of preoperative hemodynamic conditions and malperfusion due to TAAAD, and we will use it to assess the primary clinical outcomes: in-hospital mortality, late mortality, and reoperations on the aorta. We will define secondary outcomes as permanent neurologic deficit, the need for new dialysis, respiratory failure, a composite of major adverse events (myocardial infarction, cerebrovascular accidents, the need for dialysis, or the need for tracheostomy), and a composite of major adverse pulmonary events (intubation over 48 h, pneumonia, reintubation, tracheostomy), and reoperation due to bleeding.

DISCUSSION

This multicenter registry will definitively determine the prognostic significance of critical preoperative conditions and the efficacy of extended arch interventions and hemiarch repair in reducing the risk of early adverse events after surgery for TAAAD. This registry will provide insights into the long-term durability of different strategies of surgical repair for TAAAD.

Three-Dimensional-Evaluation of Aortic Changes after Frozen Elephant Trunk (FET) in Zone 0 vs. Zone 2 in Acute Type A Aortic Dissection

Introduction: The management of aortic dissection has evolved significantly over the decades, with the frozen elephant trunk (FET) procedure emerging as a key technique for treating complex aortic pathologies. Recent practices involve deploying the FET prosthesis more proximally in the aorta (Zone 0) to reduce complications, leading to questions about its impact on long-term aortic remodeling compared to traditional Zone 2 deployment. Methods: This retrospective analysis utilized 3D segmentation software to assess the volumetric changes in aortic remodeling after acute Type A aortic dissections, comparing FET stent graft deployment in Zone 0 and Zone 2. The study included 27 patients operated on between 2020 and 2022, with volumetric measurements taken from postoperative and 6-month follow-up CT scans. Statistical analyses were performed to evaluate the differences in the aortic true lumen (TL) and the perfused false lumen (PFL) between the two groups. Results: Both Zone 0 and Zone 2 deployments resulted in significant true lumen (TL) increases (Z0 p = 0.001, Z2 p < 0.001) and perfused false lumen (PFL) decreases (Z0 p = 0.02, Z2 p = 0.04), with no significant differences in volumetric changes between the groups (p = 0.7 post op and p = 0.9 after 6 months). The distal anastomosis in Zone 0 did not compromise the aortic remodeling outcomes and was associated with reduced distal ischemia and cerebral perfusion times (p = 0.041). The angle measurements in Zone 0 did not show any significant changes after the 6-month control (p = 0.2). However, in Zone 2, a significant change was detected. (p = 0.022). The part comparison analyses did not indicate significant differences in aortic deviation between the groups (p = 0.62), suggesting comparable effectiveness in aortic remodeling. Conclusions: Performing the distal anastomosis more proximally in Zone 0 offers technical advantages without compromising the effectiveness of aortic remodeling compared to the traditional Zone 2 deployment. This finding supports the continued recommendation of Zone 0 deployment in the management of acute Type A aortic dissections, with ongoing studies being needed to confirm the long-term outcomes and survival benefits.

Total aortic arch replacement using a frozen elephant trunk device: Results of a 1-year US multicenter trial

OBJECTIVE

In this prospective US investigational device exemption trial, we assessed the safety and 1-year clinical outcomes of the Thoraflex Hybrid device (Terumo Aortic) for the frozen elephant trunk technique to repair the ascending aorta, aortic arch, and descending thoracic aorta.

METHODS

For the trial, which involved 12 US sites, 65 patients without rupture were recruited into the primary study group, and 9 patients were recruited into the rupture group. All patients underwent open surgical repair of the ascending aorta, aortic arch, and descending thoracic aorta in cases of aneurysm and/or dissection. The primary end point was freedom from major adverse events (MAE), defined as permanent stroke, permanent paraplegia/paraparesis, unanticipated aortic-related reoperation (excluding reoperation for bleeding), or all-cause mortality.

RESULTS

In the primary study group, 2 patients were lost to follow-up at 1 year. Freedom from MAE at 1 year was 81% (51/63). Seven patients (11%) died (including 2 before 30 days or discharge), 3 patients (5%) suffered permanent stroke, and 3 (5%) developed permanent paraplegia/paraparesis. Twenty-six patients (41%) underwent planned extension procedures, including 22 endovascular procedures within a median of 122 (interquartile range, 64-156) days. In the aortic rupture group, 2 patients were lost to follow-up at 1 year. Freedom from MAE at 1 year was 71% (5/7). One patient (14%) died, 2 patients (29%) had permanent stroke, and none had permanent paraplegia/paraparesis. No extension procedures were performed in the rupture group.

CONCLUSIONS

One-year results with the Thoraflex Hybrid device are acceptable. Long-term data are necessary to assess the durability of these repairs.

Frozen elephant trunk versus conventional proximal repair of acute aortic dissection type I

Objective

The extent of surgery and the role of the frozen elephant trunk (FET) for surgical repair of acute aortic dissection type I are still subjects of debate. The aim of the study is to evaluate the short- and long-term results of acute surgical repair of aortic dissection type I using the FET compared to standard proximal aortic repair.

Methods

Between October 2009 and December 2016, 172 patients underwent emergent surgery for acute type I aortic dissection at our center. Of these, n = 72 received a FET procedure, while the other 100 patients received a conventional proximal aortic repair. Results were compared between the two surgery groups. The primary endpoints included 30-day rates of mortality and neurologic deficit and follow-up rates of mortality and aortic-related reintervention.

Results

Demographic data were comparable between the groups, except for a higher proportion of men in the FET group (76.4% vs. 60.0%, p = 0.03). The median age was 62 years [IQR (20), p = 0.17], and the median log EuroSCORE was 38.6% [IQR (31.4), p = 0.21]. The mean follow-up time was 68.3 ± 33.8 months. Neither early (FET group 15.3% vs. proximal group 23.0%, p = 0.25) nor late (FET group 26.2% vs. proximal group 23.0%, p = 0.69) mortality showed significant differences between the groups. There were fewer strokes in the FET patients (FET group 2.8% vs. proximal group 11.0%, p = 0.04), and the rates of spinal cord injury were similar between the groups (FET group 4.2% vs. proximal group 2.0%, p = 0.41). Aortic-related reintervention rates did not differ between the groups (FET group 12.1% vs. proximal group 9.8%, p = 0.77).

Conclusion

Emergent FET repair for acute aortic dissection type I is safe and feasible when performed by experienced surgeons. The benefits of the FET procedure in the long term remain unclear. Prolonged follow-up data are needed.

Hemiarch versus extended arch repair for acute type A dissection: Results from a multicenter national registry

OBJECTIVE

We compared perioperative outcomes of patients with acute type A aortic dissection undergoing hemiarch (HA) versus extended arch (EA) repair with or without descending aortic intervention.

METHODS

Nine hundred twenty-nine patients underwent acute type A aortic dissection repair (2002-2021, 9 centers) including open distal repair (HA) with or without additional EA repair. EA with intervention on the descending aorta (EAD) included elephant trunk, antegrade thoracic endovascular aortic replacement, or uncovered dissection stent. EA with no descending intervention (EAND), included unstented suture-only methods. Primary outcomes were in-hospital mortality, permanent neurologic deficit, computed tomography malperfusion resolution, and a composite. Multivariable logistic regression was also performed.

RESULTS

Mean age was 66 ± 18 years, 30% (278 out of 929) were women, and HA was performed more frequently (75% [n = 695]) than EA (25% [n = 234]). EAD techniques included: dissection stent (39 out of 234 [17%]), thoracic endovascular aortic replacement (18 out of 234 [7.7%]), and elephant trunk (87 out of 234 [37%]). In-hospital mortality (EA: n = 49 [21%] and HA: n = 129 [19%]; P = .42), and neurological deficit (EA: n = 43 [18%] and HA: n = 121 [17%]; P = .74) were similar. EA was not independently associated with death (EA vs HA odds ratio, 1.09; 95% CI, 0.77-1.54; P = .63) or neurologic deficit (EA vs HA odds ratio, 0.85; 95% CI, 0.47-1.55; P = .59). Composite adverse events differed significantly (EA vs HA odds ratio, 1.47; 95% CI, 1.16-1.87; P = .001). Malperfusion resolved more frequently after EAD (EAD: n = 32 [80%], EAND: n = 18 [56%], HA: n = 71 [50%]; P = .004), although multivariable analysis was not significant (EAD vs HA odds ratio, 2.17; 95% CI, 0.83-5.66; P = .10).

CONCLUSIONS

Extended arch interventions pose similar perioperative mortality and neurologic risks as Hemiarch. Descending aortic reinforcement may promote malperfusion restoration. Extended techniques should be approached with caution in acute dissection due to increased risk of adverse events.

Evidence-based frozen elephant trunk practice: a narrative review

Background and Objective

The frozen elephant trunk (FET) allows a single-stage repair of complex arch pathologies due to its stented and non-stented hybrid prosthesis (HP) features. FET inherently has its own related complications including distal stent graft-induced new entry (dSINE), failure of aortic remodelling, endoleak, reintervention, and kinking of the stent. The aim of this narrative review is to discuss the latest evidence regarding the postoperative clinical outcomes of the FET procedure. Another aim is to provide an overview of results achieved using different FET devices on the global arch prostheses market.

Methods

A comprehensive literature search was conducted using multiple electronic databases to identify and extract the relevant data and information.

Key Content and Findings

This review found that the literature reported a 5-12% mortality rate post-FET, with varying figures depending on the prosthesis type. Between 0-18.2% of patients developed dSINE, while 0.1-28% developed endoleak. Reintervention occurred in 0-28% of patients and the incidence of kinking has been quoted between 0-8% in the literature. Reporting aortic remodelling rates was challenging due to the lack of standardisation and various measurements reported; however, all studies included in this review reported relative increase in true lumen diameter, reduction in the false lumen diameter, and/or false lumen thrombosis.

Conclusions

In conclusion, FET can achieve a favourable postoperative profile in terms of survival, complications and aortic remodelling, and remains the gold-standard treatment for thoracic aortic pathologies implicating the arch and descending thoracic aorta.

Management of the left subclavian artery during aortic arch replacement using a frozen elephant trunk approach: a review

The frozen elephant trunk (FET) technique for total aortic arch replacement extends repair into the proximal portion of the descending thoracic aorta. Several techniques and modifications of total arch replacement have been described in the literature, and many of these iterations are related to facilitating the distal anastomosis while preserving flow to the left subclavian artery (LSCA), as well as maintaining posterior circulation of the brain via the vertebral artery, by reducing the circulatory arrest time during reconstruction. Because of the LSCA's posterior and deep anatomic location in the chest, particularly in obese patients, this revascularization is often challenging; additional concerns regarding LSCA revascularization include patients with large aortic arch aneurysms, those with dissected or calcified arteries, and reoperation. A careful plan for reconstruction is necessary. Whether revascularization is performed preoperative, intraoperative, or postoperatively, every effort should be made to include the left subclavian artery as part of the operational approach. Revascularization techniques include reimplantation as part of the island patch or direct anastomosis, stenting, bypass, transposition or a hybrid approach. The importance of maintaining circulation of the LSCA cannot be overstated. Preserving flow to the spinal cord via collaterals minimizes the risk of cord injury during FET procedure. In patients with a patent left internal mammary artery bypass, left arm arteriovenous fistula for hemodialysis, dominant circulation, or direct aortic origin of the left vertebral artery, revascularization is necessary as well. In the case of initial sacrifice, arm claudication or steal syndrome usually dictates delayed extra-anatomic revascularization in the postoperative period.

Emergent hybrid surgical approaches for non-dissecting ruptured Kommerell's aneurysm: a case report series

BACKGROUND

Kommerell's aneurysm is a saccular or fusiform dilatation found in 3-8% of Kommerell's diverticulum cases. A non-dissecting rupture rate of 6% has been reported. If ruptured, emergent surgical correction is usually granted. However, evidence regarding the optimal surgical approach in this acute setting is scarce. In this case report series, we aim to describe our experience managing type-1 non-dissecting ruptured Kommerell's aneurysm with hybrid emergent surgical approaches.

CASES PRESENTATION

From January 2005 to December 2020, three cases of type-1 non-dissecting ruptured Kommerell's aneurysm requiring emergent surgical repair were identified. The mean age was 66.67 ± 7.76 years, and 3/3 were male. The most common symptoms were atypical chest pain, dyspnoea, and headache (2/3). The mean aneurysm's diameter was 63.67 ± 5.69 mm. Frozen Elephant Trunk was the preferred surgical approach (2/3). The Non-Frozen Elephant Trunk patient underwent a hybrid procedure consisting of a supra-aortic debranching and a zone-2 stent-graft deployment. We found a mean clamp time of 140 ± 60.75 min, cardiac arrest time of 51.33 ± 3.06 min, and a hospital stay of 13.67 ± 5.51 days. The most common complications were surgical-site infection and shock (2/3). Only one patient died (1/3).

CONCLUSION

Evidence of management for non-dissecting ruptured Kommerell's aneurysms is scarce. Additional, robust, and more extensive studies are required. The selection of the appropriate surgical approach is challenging, and each patient should be individualized. Frozen Elephant Trunk was feasible for patients requiring emergent surgical repair in our centre. However, other hybrid or open procedures can be performed.

Initial Asian experience of the branched E-vita open NEO in complex aortic pathologies

Background

Aortic arch pathology often requires staged segmental repairs. Total aortic arch replacement with frozen elephant trunk (FET) offers surgical options for these pathologies. The Jotec E-vita Open NEO™ branched prosthesis was introduced in 2020; we sought to share our initial experience focusing on the prosthesis selection strategies, surgical techniques, anastomosis-bleeding and graft-oozing control methods, and early clinical outcomes from two Asian centers.

Methods

We performed a retrospective cohort study in patients with aortic arch pathologies who underwent total arch replacement using the FET procedure with Jotec E-vita Open NEO™ branched prosthesis from two Asian centers between October 2020 and August 2021. The primary outcome was overall 30-day mortality, and the secondary outcomes were operative complications.

Results

Twenty-five consecutive patients underwent total arch replacement with FET with the novel hybrid prosthesis. Overall 30-day mortality from both centers was 0%. Overall mean operative, cardiopulmonary bypass, hypothermic circulatory arrest, and selective antegrade cerebral perfusion times were 353.4±80.5, 183.2±39.6, 57.2±14.7, and 138.2±28.6 minutes, respectively. No patient developed stroke. Permanent spinal cord injury (SCI) was recorded in one patient (4%) and one (4%) had transient lower limb weakness that resolved after spinal drainage. There was no requirement of re-sternotomy for hemostasis.

Conclusions

We reported a multicenter Asian case series with the novel FET hybrid prosthesis demonstrating the feasibility and safety of promising initial clinical outcomes. The technique of circumferential reinforcement of vascular anastomosis for hemostasis may be one of the methods for lowering the rates of re-sternotomy for hemostasis, and proper surgical or transfusion strategies would overcome the excessive oozing of the prosthesis. Long-term follow-up is required for further evaluation of aortic pathology progression and device-related outcomes.

Systematic total arch replacement with thoraflex hybrid graft in acute type A aortic dissection: A single centre experience

Introduction

In the last two decades, a more aggressive approach has been encouraged to treat patients with acute type A aortic dissection (ATAAD), extending the repair to the aortic arch and proximal descending thoracic aorta with the frozen elephant trunk (FET) implantation. Here, we report our single-centre experience with the FET technique for the systematic treatment of emergency type A aortic dissection.

Materials and methods

Between December 2017 and January 2022, 69 consecutive patients were admitted with ATAAD; of those, 66 patients (62.9 ± 10.2 years of age, 81.8% men) underwent emergency hybrid aortic arch and FET repair with the multibranched Thoraflex hybrid graft and were enrolled in the study. Primary endpoints were 30 days- and in-hospital mortality. Secondary endpoints were postoperative morbidity and follow-up survival. To better clarify the impact of age on surgical outcomes, we have divided the study population into two groups: group A for patients <70 years of age (47 patients), and group B for patients ≥70 years (19 patients). Time-to-event analysis has been conducted using the Log-rank test and is displayed with Kaplan-Meier curves. A multiple Cox proportional Hazard model was developed to identify predictors of long-term survival with a stepwise backward/forward selection process.

Results

30-days- and in-hospital mortality were 10.6 and 13.6%, respectively. Stroke occurred in three (4.5%) patients. Two (3.0%) patients experienced spinal cord ischemia. We did not find any statistically significant difference between the two groups in terms of main post-operative outcomes. The multivariable Cox proportional hazard model showed left ventricular ejection fraction (HR: 0.83, 95% CI: 0.79–0.92, p < 0.01), peripheral vascular disease (HR: 15.8, 95% CI: 3.9–62.9, p < 0.01), coronary malperfusion (HR: 0.10, 95% CI: 0.01–0.77, p =0.03), lower limbs malperfusion (HR: 5.1, 95% CI: 1.10–23.4, p = 0.04), and cardiopulmonary bypass time (HR: 1.02, 95% CI: 1–1.04, p = 0.01) as independent predictors of long term mortality.

Conclusions

Frozen elephant trunk repair to treat emergency type A aortic dissection appears to be associated with good early and mid-term clinical outcomes even in the elderly.

Aortic remodeling, distal stent-graft induced new entry and endoleak following frozen elephant trunk: A systematic review and meta-analysis

BACKGROUND

The introduction of the frozen elephant trunk (FET) technique for total arch replacement (TAR) has revolutionized the field of aortovascular surgery. However, although FET yields excellent results, the risk of certain complications requiring secondary intervention remains present, negating its one-step hybrid advantage over conventional techniques. This systematic review and meta-analysis sought to evaluate controversies regarding the incidence of FET-related complications, with a focus on aortic remodeling, distal stent-graft induced new entry (dSINE) and endoleak, in patients with type A aortic dissection (TAAD) and/or thoracic aortic aneurysm.

MATERIALS AND METHODS

A comprehensive literature search was conducted using multiple electronic databases including EMBASE, Scopus, and PubMed/MEDLINE to identify evidence on TAR with FET in patients with TAAD and/or aneurysm. Studies published up until January 2022 were included, and after applying exclusion criteria, a total of 43 studies were extracted.

RESULTS

A total of 5068 patients who underwent FET procedure were included. The pooled estimates of dSINE and endoleak were 2% (95% confidence interval [CI] 0.01-0.06, I²  = 78%) and 3% (95% CI 0.01-0.11, I²  = 89%), respectively. The pooled rate of secondary thoracic endovascular aortic repair (TEVAR) post-FET was 7% (95% CI 0.05-0.12, I²  = 89%) while the pooled rate of false lumen thrombosis at the level of stent-graft was 91% (95% CI 0.75-0.97, I²  = 92%). After subgroup analysis, heterogeneity for distal stent-graft induced new entry (dSINE) and endoleak resolved among European patients, where Thoraflex Hybrid (THP) and E-Vita stent-grafts were used (both I²  = 0%). In addition, heterogeneity for secondary TEVAR after FET resolved among Asians receiving Cronus (I²  = 15.1%) and Frozenix stent-grafts (I²  = 1%).

CONCLUSION

Our results showed that the FET procedure in patients with TAAD and/or aneurysm is associated with excellent results, with a particularly low incidence of dSINE and endoleak as well as highly favorable aortic remodeling. However the type of stent-graft and the study location were sources of heterogeneity, emphasizing the need for multicenter studies directly comparing FET grafts. Finally, THP can be considered the primary FET device choice due to its superior results.

Endovascular reintervention after frozen elephant trunk: where is the evidence?

The introduction of the single-step hybrid frozen elephant trunk (FET) procedure for total arch replacement has revolutionized the field of aortovascular surgery. FET has proven to achieve excellent results in the repair of complex thoracic aorta pathologies. However, there remains a risk of reintervention post-FET for a variety of causes. This secondary intervention can either be performed endovascular, with thoracic endovascular aortic repair (TEVAR), or via open surgery. Multiple FET hybrid prosthesis are commercially available, each requiring different rates of endovascular reintervention. The current review will focus on providing an overview of the reintervention rates for main causes in relation to the FET grafts on the market. In addition, strategies to prevent reintervention will be highlighted. A comprehensive literature search was conducted on multiple electronic databases including PubMed, Ovid, Scopus and Embase to highlight the evidence in the literature on endovascular reintervention after FET. The main causes for secondary intervention are distal stent graft-induced new entry (dSINE), endoleak and negative aortic remodeling, and to a much lesser extent, graft kinking and aorto-esophageal fistulae. In addition, it is clear that the Thoraflex Hybrid (Terumo Aortic, Inchinnan, UK) is the superior FET device, showing excellent reintervention rates for all the above causes. Interestingly, the choice of FET device as well as its size and length can help prevent the need for reintervention. The FET procedure is indeed associated with excellent clinical outcomes, however, the need for reintervention may still arise. Importantly, the Thoraflex Hybrid prosthesis has shown excellent results when it comes to endovascular reintervention. Finally, several strategies exist that can prevent reintervention.

The great vessel freeze-out: A meta-analysis of conventional versus frozen elephant trunks in aortic arch surgery

Background

The optimal treatment strategy for complex aortic arch and proximal descending aortic pathologies remains controversial. Despite the frozen elephant trunk (FET) technique's increasing popularity, its use over the conventional elephant trunk (CET) remains a matter of physician preference and outcomes are varied.

Methods

This meta‐analysis of available comparative studies of FET versus CET sought to examine differences in survival, reintervention, and adverse events. The following databases were searched from inception—May 2020: Ovid MEDLINE, Ovid EMBASE, and The Cochrane Library. Studies retrieved were then screened for eligibility against predefined inclusion/exclusion criteria with a protocol registered on Open Science Framework at https://osf.io/hrfze/.

Results

The search identified 1911 citations, with five studies included. The resultant meta‐analysis included 313 CET and 292 FET cases. FET had lower perioperative mortality (risk ratio [RR]: 0.50, 95% confidence interval [CI]: [0.42; 0.60], p < .001) and improved 1‐year survival compared to CET (hazard ratio: 0.63, 95% CI: [0.42; 0.95], p = .03). There were no significant differences in rates of overall or open reinterventions following FET versus CET, but FET did yield a significantly higher rate of endovascular reintervention (RR: 2.32, 95% CI: [1.17; 4.61], p = .03). No significant differences were observed in the incidences of postoperative stroke, spinal cord injury, or renal failure between groups.

Conclusions

The FET technique yields superior rates of perioperative and medium‐term survival with no significant increase in overall reinterventions. There was no significant difference in the rate of spinal cord injury between groups, providing further large‐scale evidence that the FET is an acceptable, safe alternative to the CET.

Rapid enlargement of pulmonary benign metastasizing leiomyoma with fluid-containing cystic change: a case report

Background

Pulmonary benign metastasizing leiomyoma (PBML) is a rare disease that can occur in women with a history of uterine leiomyoma. Despite its benign histological features, like a malignancy, leiomyomas can on rare occasion spread to the lung. Typically, PBML presents with asymptomatic multiple solid lung nodules with slow tumor progression, following hysterectomy. Here, we present an atypical case with rapid enlargement of PBML with fluid-containing cystic change.

Case presentation

We experienced a case of a 49-year-old woman with bilateral lung nodules following hysterectomy. Two nodules in the right lung had cystic change with fluid in the tumors. Hormone therapy was initiated after surgical biopsy of the left lung confirmed a diagnosis of PBML. However, the cystic component of right upper lobe lesion enlarged rapidly over the following 7 months, and, considering the risk of malignant transformation or tumor rupture, right upper lobectomy was performed. Pathologically, the fluid-containing tumor was diagnosed as PBML.

Conclusion

Given the risk of rapid progression, we should carefully consider the surgical indications of fluid-containing PBML.

“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.

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

Background

The widespread adoption of the frozen elephant trunk (FET) technique for total arch reconstruction (TAR) in aortic arch aneurysm and dissection has led to the development of numerous commercial single-piece FET devices, each with its own unique design features. One such device, Thoraflex™ Hybrid (Terumo Aortic, Glasgow, Scotland), has enjoyed widespread use since its introduction. We present and appraisal of its long-term clinical efficacy, based on international data.

Materials and Methods

Pre-, intra-, and postoperative data associated with Thoraflex™ Hybrid implantations for aortic arch dissection, aneurysm, and penetrating atherosclerotic ulcer (PAU) up to April 2019 was gathered and is presented herein. Follow-up data at discharge, 3-, 6-, 12-, 24-, 36-, 48-, 60-, 72-, and 84- months post-implantation are included.

Results

Data associated with 931 cases of Thoraflex™ Hybrid implantation are included. Mean age at implantation was 63 ± 12 years. 55% of patients included were male. Aortic dissection accounted for 48% (n = 464) of cases. Mean cardiopulmonary bypass and circulatory arrest durations were 202 +72 and 69 ± 50 min, respectively. 30-day mortality was 0.6% (n = 6), while overall mortality was 14 (1.5%). Freedom from adverse events at 84 months was 95% (n = 869). Postoperative complications included neurological deficit, multi-organ failure, cardiorespiratory compromise, and infection.

Discussion

Thoraflex™ Hybrid's unique design is advantageous in comparison to market alternatives. Our data is consistent with that reported in literature and suggests Thoraflex™ Hybrid is associated with favourable rates of mortality and morbidity.

Conclusion

Thoraflex™ Hybrid remains a central player in the aortic arch prosthesis market. Its use it widespread and is associated with favourable design features and clinical outcomes relative to market alternatives.

Total Endovascular Aortic Arch Repair: From Dream to Reality

The gold-standard therapy for the treatment of aortic arch pathologies is conventional open surgery. Recently, total endovascular aortic arch replacement with branched stent-grafts has been introduced into clinical practice with the aim of reducing invasiveness especially in selected high-risk patients. The aim of this review is to describe the two most commonly used branched devices for endovascular arch stent-grafting: Nexus (Endospan, Herzlia, Israle) and RelayBranch (Terumo Aortic, Glasgow, United Kingdom). Nexus is a CE-certified off-the-shelf, single branch, double stent graft system. It consists of two different components: a main module for the aortic arch and the descending aorta with a side-branch for the brachiocephalic artery (BCA), and a curved module for the ascending aorta that lands into the sino-tubular junction and connects to the main module through a side-facing self-protecting sleeve. Nexus may be used in urgent-emergency cases and also in patients with only one suitable supra-aortic target vessel but, on the other hand, it makes cerebral blood flow dependent on one source vessel only. The RelayBranch Thoracic Stent-Graft System is a custom made, double branched endograft with a wide window on its superior portion to accommodate two inner tunnels for BCA and left common carotid artery connection; bilateral cervical accesses are generally used to advance guidewires for catheterization of the inner tunnels in a retrograde fashion. RelayBranch can be customized on every patient’s specific anatomy and provides a double blood source for the brain, but it cannot be used in urgent-emergency conditions. Therefore, in order to optimize outcomes, the choice of the most appropriate device should be made considering pros and cons of each system and patient’s anatomy by an experienced aortic team. In conclusion, total endovascular aortic arch exclusion is a promising reality in selected high-risk patients.

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.

“Branch-First total arch replacement”: a valuable alternative to frozen elephant trunk in acute type A aortic dissection?

The "Branch-First total arch replacement" technique has been used extensively in both elective and acute situations, including in type A aortic dissection. The focus of the Branch-First technique is to reduce the risk of neurological and end-organ dysfunction associated with arch replacement by optimising neuroprotection, distal organ perfusion and myocardial protection. The Branch-First technique is a valuable alternative to the frozen elephant trunk (FET) technique in type A aortic dissection, providing a stable landing zone for subsequent interventions on the distal aorta should they be required. Combining the Branch-First technique with FET in appropriate cases can further improve outcomes. We discuss the merits of the Branch-First technique, and contrast them to those of FET techniques for repair of type A aortic dissection.

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

The frozen elephant trunk technique (FET) requires the use of a pre-assembled hybrid prosthesis consisting of a standard Dacron vascular portion to replace the aortic arch and a stent graft component, which is placed into the proximal descending thoracic aorta (DTA) anterogradely in the proximal descending thoracic aorta. In Europe, two hybrid prostheses are available: the E-evita Open Plus hybrid stent graft system provided by JOTEC (Hechingen, Germany) and the ThoraflexTM Hybrid (Vascutek, Inchinnan Scotland). Recommendations for use are extensive pathologies of the arch in case of acute and chronic aortic dissection, degenerative aneurysm and intramural hematoma. The FET approach allows the replacement of the whole arch in one stage with the option of direct treatment of the proximal descending thoracic aorta based on the stent component, creating a safe landing zone for further endovascular treatment more distally. The remarkable feature of this technique is the possibility to perform more proximally (from zone 3 to zone 0) the distal anastomosis in to the arch. This allows for an easier distal anastomosis, reduced hypothermic circulatory arrest time and decreased risk of paraplegia (<5%). Early results are promising and according to the most recent series the rate of developing post-operative renal insufficiency ranges from 3 to 10%, the risk of stroke from 3% to 8% and mortality from 8-15%. The aim of the article will be to provide some knowledge about the use and application of FET procedures in different aortic situations.

Frozen Elephant Trunk Technique in Acute Type A Aortic Dissection: Is It for All?

Acute type A aortic dissection (ATAAD) is an indisputable emergency with very poor outcomes without surgical treatment. Although the aortic arch is often involved in the aortic dissection, its optimal management during surgical therapy remains uncertain. A conservative tear-oriented approach has traditionally been adopted, limiting the procedure to the ascending aorta (or hemiarch) replacement. However, dilation of the residual dissected aorta and subsequent rupture may occur, requiring further intervention in the future. In the last two decades, the frozen elephant trunk (FET) technique has become a valid and attractive option to treat aortic disease when the arch and the thoracic aorta are involved, both in elective and in emergency settings. Here, we report a review of the contemporary literature regarding the short- and long-term outcomes of the FET technique in ATAAD repair.

Frozen Elephant Trunk in Right Aberrant Subclavian Artery

Aberrant right subclavian artery (ARSA) is a relatively rare congenital anomaly of the aortic arch. A 74-year-old woman was referred to our Cardiac Surgery Department for chest pain. Angio-CT scan showed an acute aortic dissection and revealed an ARSA routed behind the trachea. We performed supra-coronary ascending aorta and total arch replacement with Frozen Elephant Trunk (FET) technique. The ARSA was then termino-terminal anastomosed to one branch of the Thoraflex arch graft. Postoperative CT-scan indicated a successful reconstruction of the aortic arch, proving the open stent-grafting technique as a useful and effective approach for aortic disease with ARSA.

Frozen Elephant Trunk for Aortic Arch Reconstruction is Associated with Reduced Mortality as Compared to Conventional Techniques

To examine the perioperative outcomes following aortic arch repair using frozen elephant trunk (FET) vs conventional elephant trunk (ET) techniques. Between 2002 and 2018, 390 patients underwent aortic repair with elephant trunk reconstruction at 9 centers: 172 patients received a FET (mean age: 65+/-13 years, 30% female, 37% aortic dissection) and 218 patients received an ET (mean age: 63+/-13 years, 37% female, 43% aortic dissection). Outcomes of interest included in-hospital mortality; stroke; and spinal cord injury (SCI). In-hospital mortality rate was 11% (n = 43) overall, 9% (n = 15) for FET and 13% (n = 28) for ET. Post-operative stroke occurred in 13% (n = 49) overall, 13% (n = 22) for FET and 12% (n = 27) for ET. The rate of post-operative SCI was 3% (n = 13) overall, 5.0% (n = 9) for FET and 2.0% (n = 4) for ET. When compared to ET, the propensity score analysis confirmed FET to be associated with lower mortality (adjusted risk difference -7.0% (95% CI -13.0 to -1.0), P = 0.02). There was no significant difference in the propensity score-adjusted risk difference for stroke between FET and ET (-0.7%, 95% CI -7.4% to 6.1%, P = 0.85), nor for SCI (3.3%, 95% CI -0.4% to 7.0%, P = 0.085) On multivariable analysis, FET was associated with lower odds of mortality (OR 0.44, 95% CI 0.21-0.95, P = 0.04), and had similar odds of stroke (OR 0.83, 95% CI 0.41-1.70, P = 0.62) and SCI (OR 2.83, 95% CI 0.83-9.60, P = 0.1). FET repair is associated with lower in-hospital mortality as compared to conventional ET, and results in similar risk of stroke and spinal cord injury. Further investigation is warranted.

"Proximalization is Advancement"-Zone 3 Frozen Elephant Trunk vs Zone 2 Frozen Elephant Trunk: A Literature Review

Over the decades, the Frozen Elephant Trunk (FET) technique has gained immense popularity allowing simplified treatment of complex aortic pathologies. FET is frequently used to treat aortic conditions involving the distal aortic arch and the proximal descending aorta in a single stage. Surgical preference has recently changed from FET procedures being performed at Zone 3 to Zone 2. There are several advantages of Zone 2 FET over Zone 3 FET including reduction in spinal cord injury, visceral ischemia, neurological and cardiovascular sequelae. In addition, Zone 2 FET is a technically less complicated procedure. Literature on the comparison between Zone 3 and Zone 2 FET is scarce and primarily observational and anecdotal. Therefore, further research is warranted in this paradigm to substantiate current surgical treatment options for complex aortic pathologies. In this review, we explore literature surrounding FET and the reasons for the shift in surgical preference from Zone 3 to Zone 2.

[Quo vadimus? Fundamental problems of developing hybrid prostheses of thoracic aorta]

This article is a review briefly characterizing the state of the art of hybrid surgery of the thoracic aorta using the frozen elephant trunk technique worldwide and in Russia, also discussing unsolved problems of fundamental science, being key issues in creation of new models of hybrid prostheses of the thoracic aorta. The main attention is paid to the problem of radial stiffness of the stent-graft portion of the prosthesis. Performed is a detailed analysis of the factors influencing this characteristic of the sent graft: shape, size and number of cells of the stent element, thickness of the nitinol wire it is made of, method of edge connection, nitinol properties depending on the alloy grade and methods of thermoforming. It is shown that excessive stiffness leads to the development of d-SINE syndrome. This is followed by discussing the problem of optimal stiffness of stent grafts, based on the design of stent graft elements and elastic properties of the wall of the true channel of a dissecting aortic aneurysm. Also proposed is an approach to solving the problem of d-SINE, consisting in creation of conical stent grafts and/or a gradual decrease of radial stiffness of stent elements in the direction of the distal portion. Comprehensively addressed are disadvantages of the graft portion of the prosthesis, in 95% of items made of polyethylene terephthalate fiber: susceptibility to degradation associated with manufacturing defects and intraoperative microdamages, abrasive effect in the zone of contact with stent elements, partial postoperative hydrolysis and an inflammatory reaction to a foreign body, often being clinically pronounced. Also touched upon are certain aspects of creating hermetic coatings of the graft portion, with the use of vancomycin possessing low cytotoxicity as part of an antibacterial component being promising. As a whole, it is demonstrated that advances in creating a novel generation of hybrid prostheses should be associated with new approaches and materials, to be obtained at the junction of medicine and fundamental sciences.

Zone 1 Debranching for Frozen Elephant Trunk and Whole-Body Perfusion

A 65-year-old man with chronic type A aortic dissection underwent zone 1 debranching and frozen elephant trunk with whole-body perfusion. This approach has the potential to improve technical feasibility of the frozen elephant trunk procedure and reduce its ischemic complications.

Aortic arch aneurysms and dissection-open repair is the gold standard

The aortic arch repair is one of the most complex surgeries and carries a high risk of complications as well as mortality. Since 1975, when the arch repair was first done by Randall B. Griepp using hypothermic circulatory arrest, many new technologies were introduced. But even with the use of antegrade and retrograde perfusion techniques and improvement of surgical techniques and grafts, the rate of mortality, cerebral, spinal, and visceral damage was much higher as compared to any other cardiac surgeries. With further developments aimed at less invasive approaches, thoracic endovascular aortic repair (TEVAR) along with de-branching of supra-aortic vessels or the frozen elephant trunk was introduced. Here, in this article, we review the myriad of approaches to the aortic arch and have come to a conclusion that while traditional open surgery is considered as the gold standard for treatment of extensive aortic arch pathologies, one school of thought suggests hybrid techniques such as the frozen elephant trunk and aortic arch vessel de-branching as more appropriate procedures for high-risk patients, where co-morbidities may contraindicate cardiopulmonary bypass and longer operative times required for traditional repair. No randomized trials are present to compare between open and hybrid or endovascular procedure in normal or high-risk patients. The meta-analysis of most of the studies defines open surgery as the gold standard for arch pathology because the hybrid procedures did not provide any proven survival benefits or decrease in stroke rate and spinal ischemia when compared to open surgery in early, mid, or long-term results.

Total aortic arch replacement using elephant trunk or frozen elephant trunk technique: a case-control matching study

Background

Surgical management of aortic arch diseases is one of the most challenging issues in cardiovascular surgery. The aim of this study was to compare the outcome after frozen elephant trunk (FET) with conventional elephant trunk (ET) technique.

Methods

Out of a total of 551 patients after thoracic aortic surgery, we analyzed 70 consecutive patients, who underwent aortic arch replacement with ET or FET technique between 2001 and 2017 in our institution. The patients were case-control matched in regard to such variables as age, sex, presence of an acute aortic dissection and necessity for concomitant procedures. The analysis included 25 patient pairs.

Results

Among the 25 FET patients, eleven patients were female, the median age was 69, 15 (60%) patients had an aortic dissection and thirteen needed various concomitant procedures. In the second group, treated with conventional ET technique, 10 (40%) patients were female, the median age was 66 years, thirteen presented with an aortic dissection and 16 (64%) underwent concomitant procedures. These and other characteristics did not differ significantly between the groups. In-hospital mortality was statistically similar: 5 (20%) in the FET group vs. 8 (32%) for ET group (P=0.52). The incidence of stroke, acute renal failure and postoperative bleeding was comparable. The length of stay in the intensive care unit did not differ between the cohorts (P=0.258). Predictors of in-hospital mortality were length of the operation, bleeding postoperatively, and acute renal failure. The one-year survival rates were higher in the FET cohort compared to the conventional approach (60% vs. 38%), however without statistical significance.

Conclusion

In regard to the short- and mid-term outcome, there were only slight differences between both techniques. In patients with extensive aneurysmal aortic disease, conventional ET and FET procedures seem to be associated with acceptable satisfactory mid-term outcome.

Aortic Arch Reconstructive Surgery With Conventional Techniques vs Frozen Elephant Trunk: A Systematic Review and Meta-Analysis

BACKGROUND

Frozen elephant trunk (FET) surgery offers a new alternative in the management of complex thoracic aortic aneurysms and dissections. We performed a systematic review and meta-analysis of comparator observational studies evaluating the efficacy of FET compared with conventional aortic arch surgery, primarily focusing on mortality and stroke as well as the secondary outcomes of spinal cord ischemia, major bleeding, and operative time.

METHODS

We searched MEDLINE, EMBASE, PubMed, and the Cochrane Library for trials and studies comparing the FET technique with conventional surgery in patients with aortic aneurysms or dissections, or both. The overall quality of evidence was low, as assessed by Grading of Recommendations, Assessment, Development, and Evaluation, based primarily on the risk of bias secondary to study design, plausible confounding, and imprecision.

RESULTS

Meta-analysis revealed a significant reduction in mortality (12 studies, 1803 patients: odds ratio [OR], 0.55; 95% CI, 0.39-0.78) and a nonsignificant reduction in stroke (12 studies, 1803 patients: OR, 0.78; 95% CI, 0.52-1.15) favouring FET; however, FET was associated with a significant increase in spinal cord ischemia (9 studies, 1476 patients: OR, 2.20; 95% CI, 1.10-4.37). No significant differences between groups were observed regarding major bleeding, cardiopulmonary bypass time, or cross-clamp time.

CONCLUSIONS

Current evidence suggests that FET surgery is associated with lower mortality in patients with thoracic aneurysmal disease and dissections, without a significant increase in stroke, bleeding, or operative times. However, the risk of spinal cord ischemia is increased in patients who undergo FET. A well-powered randomized trial is needed to evaluate this evolving field.