Clinical outcomes of a fenestrated frozen elephant trunk technique for acute type A aortic dissection

Computed Tomography Imaging Measurements as a Surrogate for Clinical Outcomes After Surgical Management of Acute Type A Aortic Dissection: A Systematic Review

BACKGROUND

Postoperative computed tomography imaging surveillance is an essential component of care after acute type A aortic dissection (ATAAD) repair. Prognostic imaging factors after ATAAD repair have not been systematically reviewed.

METHODS AND RESULTS

We performed a systematic review to summarize postoperative computed tomography measurements including aortic diameter, cross-sectional area, volume, growth rate, and false lumen thrombosis in addition mid- to long-term clinical outcomes after ATAAD repair. Searches were conducted in Medline, Embase, and CENTRAL in October 2022. Studies were included if they reported clinical outcomes such as mortality or aortic reintervention after 1 year and included aforementioned computed tomography findings. Studies of chronic aortic dissection and studies of exclusive patient populations such as those with connective tissue diseases were excluded. Risk of bias was assessed with the Newcastle-Ottawa Scale. Searches retrieved 6999 articles. Sixty-eight studies met inclusion criteria (7885 patients). Extended repairs were associated with improved false lumen thrombosis, decreased aortic growth rate, and decreased rates of reintervention but not improved survival. Growth rates of the aorta post-ATAAD repair were highest in the descending thoracic aorta. The most frequent prognostic imaging factors reported were a patent/partially thrombosed false lumen and postoperative aortic diameter >40 to 45 mm.

CONCLUSIONS

Established measurements of positive aortic remodeling, including complete false lumen thrombosis and stabilization of postoperative aortic diameter and growth are the most studied prognostic indicators for improved clinical outcomes after ATAAD repair. Growth rate of the aorta remains significant after ATAAD repair. Future studies should prospectively evaluate and compare prognostic factors for improved surveillance and management.

Frozen elephant use in type a dissection: fundamentals, innovations, and pitfalls

INTRODUCTION

Type A acute aortic dissection (TA-AAD) is a great challenge for aortic surgeons. The establishment of a standardized surgical approach, particularly the determination of whether and when to address the aortic arch and the distal aorta in the same operation as the proximal aorta, is still unclear.

AREAS COVERED

Frozen elephant trunk (FET) has emerged as a valuable treatment for TA-AAD over the last decade. Here, we discuss the fundamentals and pitfalls of frozen elephant trunk procedures and present the latest innovations.

EXPERT OPINION

FET has the potential to simplify arch reconstruction in patients with complex arch tears and rupture, optimize perfusion in the distal true lumen for those with a compressed true lumen and malperfusion, address distal reentry tears, and promote false lumen thrombosis and late aortic remodeling. Nevertheless, FET is still associated with non-negligible mortality and morbidity rates. Patient selection, surgical expertise, and postoperative care remain crucial determinants in ensuring successful outcomes. Recent innovations in FET surgery involve the development of techniques to minimize or avoid hypothermic circulatory arrest and new FET devices with different arch branch configurations aiming to facilitate subsequent aortic reinterventions. We believe that both these advancements have the potential to improve patient outcomes.

Comparison between Zone 2 and Zone 3 distal anastomoses for aortic arch replacement in terms of invasiveness

OBJECTIVES

Zone 2 anastomosis with total cervical branch reconstruction for acute type A aortic dissection and aortic arch aneurysms became possible after stent-graft introduction. This may be an easier procedure and reduce the risk of recurrent laryngeal nerve palsy. Therefore, this study aimed to compare the outcomes between Zone 2 and Zone 3 distal anastomoses.

METHODS

After evaluating the patient data in our institute between April 2016 and April 2022, the patients in whom distal anastomosis was performed at Zone 2 with a stent-graft were defined as the Zone 2 group (n = 70). The patients in whom distal anastomosis was performed at Zone 3 were defined as the Zone 3 group (n = 24).

RESULTS

The incidence of new-onset recurrent nerve palsy was one patient (1.4%) in the Zone 2 group and six patients (25.0%) in the Zone 3 group (p < 0.001). The lower body perfusion arrest time was 44.3 ± 9.1 min in the Zone 2 group and 52.9 ± 12.8 min in the Zone 3 group (p = 0.005). There were no significant differences in in-hospital mortality and morbidities. Multivariable analysis showed that only age was an independent predictor of overall mortality.

CONCLUSIONS

Performing distal anastomosis at Zone 2 with a frozen elephant trunk or stent-graft reduced the lower body perfusion arrest time and possibly prevented recurrent nerve palsy.

Endoleak after use of the fenestrated frozen elephant trunk technique to treat acute type A aortic dissection

Several studies have indicated that the fenestrated frozen elephant trunk (FET) technique enhances early outcomes in cases of acute aortic dissection, although long-term outcomes remain unclear. A case involving a 62-year-old male who experienced endoleak from a fenestration site following total arch replacement using the fenestrated FET technique for a DeBakey type I aortic dissection is reported. The patient underwent successful reoperation involving total arch replacement and reinsertion of the FET. Postoperatively, there was an absence of endoleak from the fenestration, and a noteworthy reduction in the diameter of the aortic arch was observed. It is imperative to recognize that endoleak from a fenestration poses a risk for prompt aortic expansion, thus necessitating vigilant postoperative monitoring. Furthermore, when adopting fenestrated FET, it is crucial to ensure firm fixation around the fenestration to prevent endoleak.

Type 1a Endoleak after Fenestrated Frozen Elephant Trunk Technique

The patient was a 48-year-old man who had undergone fenestrated frozen elephant trunk (FET) technique for acute type A aortic dissection. Postoperative enhanced computed tomography (CT) imaging revealed a type 1a endoleak from the fenestration. Nevertheless, the stented portion of the FET exhibited circular expansion. However, 2 months after surgery, enhanced CT imaging revealed the flattening of the FET due to the persistent endoleak and we performed an urgent zone 2 thoracic endovascular aortic repair (TEVAR). When type 1a endoleak from the fenestration is observed, the FET can be flattened, as in this patient, additional intervention should be considered.

Overview of acute type A dissection in Japan

Acute type A aortic dissection is a relatively uncommon but devastating disease and usually requires emergency surgery. Based on the several database projects, a large amount of perioperative patient data has now been accumulated and is expected to be useful in clinical practice. Especially in Japan, the number of surgeries for acute type A aortic dissection has been gradually increasing recently, and the overall mortality rate has stabilized at less than 10%. One of the keys to further improvement in outcomes will be to improve the results of aortic root replacement. In addition, strategies need to be established for very elderly patients, comatose patients, and patients with malperfusion as preoperative conditions. The use of a relatively new device, the frozen elephant trunk, is also increasing and might be changing the surgical outcome. In this report, we describe the current status of acute type A aortic dissection in Japan, with reference to recent guidelines and literature.

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.

Case report: Total arch replacement with a frozen elephant trunk utilizing open hybrid in-situ fenestration technique for thoracic aortic arch aneurysm

Introduction

The frozen elephant trunk technique is a surgical procedure developed for concomitant repair of downstream descending thoracic aorta as a first stage operation for arch resections. Proximalization of the sutured anastomosis reduces technical difficulty of total arch replacement. In this procedure, an anastomosis is performed more proximally using a stent graft. Connect the head and neck vessels are created using in-situ fenestration method.

Case presentation

This study presents the case of a 78-year-old woman with a large thoracic aortic arch aneurysm that was successfully treated with a modified frozen elephant trunk technique (open in situ fenestration). For this method, a hole was created in the neck branches (the left subclavian artery and left common carotid artery), and peripheral stent grafts were placed to simplify neck branch reconstruction. This minimized the risk of recurrent laryngeal nerve injury and bleeding and shortened the procedure time.

Conclusion

The outcomes of this study showed a safe alternative total arch replacement procedure.

Management of noncerebral malperfusion complicating acute type A dissection

Vital organ malperfusion in acute type A aortic dissection is associated with worse outcomes, especially when multiple organ systems are involved, and when coronary or mesenteric malperfusion is present. To achieve the two goals of central aortic repair and adequate and timely reperfusion, mechanism and organ-specific strategy in the methods and sequence of repair should be considered. For dynamic aortic malperfusion, reperfusion can be quickly achieved by femoral artery perfusion, and the fenestrated frozen elephant trunk operation, in which the proximal end of device is secured to zone 1 or 2 and distal 1 or 2 supra-aortic vessels are preserved by fenestration of the fabric, seems optimal as a method of central aortic repair. For coronary malperfusion, percutaneous coronary intervention before central aortic repair may have a role. However, it should be kept in mind that the door-to-unloading time is also important to reduce the area of myocardial infarction, and retrograde cardioplegia is not distributed to most of the right ventricle, which can be critical when right coronary malperfusion is present. Static mesenteric malperfusion should be addressed first, and second-look laparotomy should not be hesitated after central aortic repair. The use of a hybrid operating room may be an optimal solution to achieve both goals.

Fenestrated and covered frozen elephant trunk technique for management of chronic aortic dissection

BACKGROUND

Reintervention for residual dissection after repaired type A aortic dissection remains challenging. When a frozen elephant trunk (FET) is used, the incidence of distal stent graft-induced new entry (d-SINE) is reportedly high in chronic dissection.

AIMS

We report a case of successful redo arch repair using fenestrated and covered FET techniques for chronic residual aortic dissection.

METHODS

After the arch was transected proximal to the left subclavian artery (LSCA), and a modified FET prosthesis, in which the distal edge of the FET was covered, was deployed. A fenestration was created in the FET on the LSCA aspect.

RESULTS

The postoperative course was uneventful.

DISCUSSION

The distal edge of the FET was covered to prevent d-SINE. Creation of a fenestration on the FET eliminates the need to reconstruct the LSCA.

CONCLUSION

The fenestrated FET technique simplifies redo arch repair and the covered FET technique can potentially prevent d-SINE.

Endovascular treatment after the fenestrated frozen elephant trunk technique

Recently, several centers have performed total arch replacement using the fenestrated frozen elephant trunk technique for acute Stanford type-A aortic dissection. However, the long-term results and need for additional treatment following this procedure are unclear. We report a case of a 54-year-old man who underwent endovascular therapy for endoleaks after total arch replacement using the fenestrated frozen elephant trunk technique for acute type-A aortic dissection with an isolated left vertebral artery. After the surgery, the endoleak was resolved, and the patient was asymptomatic with no neurological deficits. This strategy might be effective in similar cases.

Postoperative results of the in situ fenestrated open stent technique for acute aortic dissection type A

OBJECTIVE

Total arch replacement is commonly used for acute aortic dissection type A at some facilities, especially since open stent grafting became commercially available in Japan. Left subclavian artery (LSCA) reconstruction involves deep view manipulation, is difficult to expose and anastomose, and involves the risk of complications and surrounding vascular injury.

METHODS

We evaluated 137 patients (mean age 73.8 ± 15.6 years) who underwent total arch replacement for acute aortic dissection type A, at our hospital between September 2014 and March 2022, and divided them into two groups: 70 patients for total arch replacement with fenestrated open stent technique (FeneOS), and 67 for conventional total arch replacement with the reconstruction of three-branch cerebral vessels. We performed FeneOS by deploying the graft from the entry of the left subclavian artery into the descending aorta and fenestrating the LSCA side of the stenting portion. The four-branched artificial vessel was then anastomosed between the left common carotid artery and LSCA.

RESULTS

The surgical results of FeneOS were satisfactory and enabled significant reductions in operative time, selective cerebral perfusion time, cardiopulmonary bypass time, and lower body circulatory arrest time. Long-term observation (mean follow-up = 5.5 years) showed no left recurrent laryngeal nerve palsy or postoperative problems with left subclavian artery blood flow.

CONCLUSIONS

FeneOS can minimize LSCA exposure because there is no need for LSCA reconstruction, reducing operation time and avoiding the risk of left recurrent laryngeal nerve injury and bleeding problems associated with LSCA exposure and anastomosis during left subclavian artery exposure.

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.

Effects of a frozen elephant trunk on postoperative renal dysfunction in acute type A aortic dissection extending into the renal artery

BACKGROUND

We investigated the effects of frozen elephant trunk (FET) implantation on clinical outcomes in patients with acute type A aortic dissection (ATAAD) extending into the renal artery (RA).

METHODS

Between May 2016 and April 2021, 136 patients underwent surgery for ATAAD at our hospital. Patients who died within 7 days postoperatively and those without preoperative contrast-enhanced computed tomography (CT) data were excluded from the study. The remaining 125 patients were included in this study. A preoperative CT-documented RA abnormality was found in 53 patients. Clinical outcomes, including renal dysfunction and CT findings, were compared between 29 patients with and 24 patients without the FET prosthesis.

RESULTS

Among the 53 patients with RA abnormalities, origin of the RA from the false lumen was the most common type of abnormality. The percentage of men and rate of arch repair were higher, and the operation, cardiopulmonary bypass, and lower body hypothermic circulatory arrest times were longer in the FET than in the non-FET group. Early mortality rates were similar between groups. The incidence of postoperative acute kidney injury (AKI) was lower in the FET group (35% vs. 67%, p = 0.028). Multivariable analysis showed that FET implantation was associated with a low incidence of AKI (odds ratio: 0.28, 95% confidence interval: 0.08-0.96; p = 0.043). Among the 125 patients with or without RA abnormalities, no predictor of AKI was identified.

CONCLUSION

FET implantation protected against postoperative AKI in patients with ATAAD extension into the RA.

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.

OUP accepted manuscript

Distal stent graft-induced new entry is not rare after frozen elephant trunk implantation. We report a case of covered frozen elephant trunk placement for prevention of distal stent graft-induced new entry. Coverage of the rigid distal stent edge using a graft reduces mechanical stress on the intima and radial force of the distal stent; therefore, this technique can potentially prevent distal stent graft-induced new entry.