A systematic review and meta-analysis on the safety and efficacy of the frozen elephant trunk technique in aortic arch surgery

Long-term outcomes of frozen elephant trunk for aortic dissection: a single-center experience

BACKGROUND

To date a number of papers analysing outcomes of the frozen elephant trunk (FET) in acute aortic dissection has been published. However, there are limited comparative studies on long-term outcomes of FET in acute and chronic aortic dissection. The objective of the study was to analyze the long-term outcomes after FET procedure for aortic dissection (AD).

METHODS

Between March 2012 and December 2022, a total of 123 FET had been performed for thoracic aortic disease. Patients with aortic dissection (n = 97) were divided into 2 groups: acute (n = 32, 33%) and chronic aortic dissection (n = 65, 67%). Pre-, intra- and postoperative data were retrospectively collected from electronic patient's records, including follow-up data of the analyzed patients.

RESULTS

The incidence of stroke was 3.1%. The delirium rate was up to 9.3% in both groups with a prevalence in chronic aortic dissection (CAD) group without significant differences (P = 0.494). Paraplegia was diagnosed only in CAD patients (n = 2). Respiratory failure and the rate of renal replacement therapy were similar in the studied groups. Re-sternotomy was required in one (3.1%) patient with acute AD and 5 (7.7%) patients with chronic AD (P = 0.416). Overall 30-day mortality in the entire cohort, acute and chronic AD was 13 (13.4%), 7 (21.9%) and 6 (9.2%), respectively (P = 0.097). The overall survival rate at 60 months for the entire cohort, acute and chronic AD was 64.1 ± 5.9%, 62.3 ± 9.1%, 66.5 ± 7%, respectively (P = 0.265). Freedom from unintended distal aortic re-intervention at 60 months for the entire cohort of patients, acute and chronic AD was 74.2 ± 1.5%, 100%, 65.3 ± 2%, respectively (P = 0.355).

CONCLUSIONS

Our experience showed acceptable long-term outcomes after the FET procedure including mortality and re-intervention rate in patients with aortic dissection regardless of acuity of the dissection.

TRIAL REGISTRATION

The study has been registered in Australian and New Zealand Clinical Trial Registry (ACTRN 12618001329257) on August 7, 2018.

Physician-modified endograft for symptomatic zone 2 penetrating ulcer of the aortic arch without bridging stenting of the left subclavian artery for vertebral preservation

We report the case of a 65-year-old male patient who was deemed unfit for open surgery and underwent zone 0 endovascular repair with a physician-modified fenestrated endograft for a symptomatic penetrating ulcer. A thoracic stent graft was modified creating a large fenestration for the innominate artery and the left common carotid artery, and a second small fenestration for the left subclavian artery and the left vertebral artery, which had a common origin. No bridging stent was used for the left subclavian artery to avoid coverage of the left vertebral artery. The postoperative course was uneventful, and no leaks nor other complications were detected on postoperative computed tomography angiography. Although long-term durability needs to be better assessed, our experience suggests that physician-modified fenestrated endografts are a feasible option for the emergent treatment of aortic arch lesions in unfit patients and provide satisfactory results in the short term.

Safety and effectiveness of the sutureless integrated stented graft prosthesis in an animal model

BACKGROUND

Prolonged circulatory arrest time is an independent risk factor for postoperative adverse events of type A aortic dissection (TAAD) surgery. Further reduction of the circulatory arrest time is essential to improve surgical outcomes. This study aimed to evaluate the safety and effectiveness of the novel Sutureless Integrated Stented (SIS) graft prosthesis in an animal experiment.

MATERIALS AND METHODS

Straight type of the SIS graft prosthesis was implanted into the descending aorta of 10 adult male sheep, and the use of the device was scored on a scale of 1-10. Aortic digital subtraction angiography (DSA) was performed at 4, 14, and 26 weeks to investigate the prostheses. After 26 weeks, the animals were sacrificed for histological analysis.

RESULTS

The immediate success rate of the surgery was 100 %, and the overall mean score of the use of the device was 9.65 ± 0.99. Three animals died from non-device-related causes during follow-up. Aortic DSA showed filling defects in 5 animals. Histological analysis revealed that all prostheses were intact. Except for 2 early deaths, the other 8 prostheses were endothelialized with mild inflammation, foreign body reactions, and intimal fibrosis. The mean cross-sectional area of the sutureless region was reduced by 26.4 % (range, 1.3-39.1 %).

CONCLUSIONS

The safety and effectiveness of the novel SIS graft prosthesis were acceptable, and the delivery system exhibited a promising performance. Using the SIS graft prosthesis in TAAD surgery was expected to simplify the procedures and shorten the circulatory arrest time. Further large-scale clinical trials are required to verify these findings.

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.

The role of intraoperative extensor digitorum brevis muscle MEPs in spinal surgery

PURPOSE

Intraoperative muscle motor evoked potentials (m-MEPs) are widely used in spinal surgery with the aim of identifying a damage to spinal cord at a reversible stage. Generally, lower limb m-MEPs are recorded from abductor hallucis [AH] and the tibialis anterior [TA]. The purpose of this work is to study an unselected population by recording the m-MEPs from TA, AH and extensor digitorum brevis (EDB), with the aim of identifying the most adjustable and stable muscles responses intraoperatively.

METHODS

Transcranially electrically induced m-MEPs were intraoperative recorded in a total of 107 surgical procedures. m-MEPs were recorded by a needle electrode placed in the muscle from TA, AH and EDB muscles in the lower extremities.

RESULTS

Overall monitorability (i.e., at least 1 Lower Limb m-MEP recordable) was 100/107 (93.5%). In the remaining 100 surgeries in 3 cases, the only muscle that could be recorded at baseline was one AH, and in other 2 the EDB. Persistence (i.e., the recordability of m-MEP from baseline to the end of surgery) was 88.7% for TA, 89.8% for AH and 93.8% for EDB.

CONCLUSION

In our series, EDB m-MEPs have demonstrated a recordability superior to TA and a stability similar to AH. The explanations may be different and range from changes in the excitability of the cortical motor neuron to the different sensitivity to ischemia of the spinal motor neuron. EDB can be used alternatively or can be added to TA and AH as a target muscle of the lower limb in spinal surgery.

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.

Early and midterm results of frozen elephant trunk operation with Evita open stent-graft in patients with Marfan syndrome: results of a multicentre study

BACKGROUND

Endovascular treatment of patients with Marfan syndrome (MFS) is not recommended. Hybrid procedures such as frozen elephant trunk (FET), which combines stent-graft deployment with an integrated non-stented fabric graft for proximal grafting and suturing, have not been previously evaluated. The aim of this study was to assess the safety and feasibility of FET operation in patients with MFS.

METHODS

Patients enrolled in the International E-vita Open Registry (IEOR) who underwent FET procedure between January 2001 and February 2020 meeting Ghent criteria for MFS were included in the study. Early and midterm results were retrospectively analyzed. Preoperative, postoperative and follow-up computed tomography angiography scans were analysed.

RESULTS

We analyzed 37 patients [mean age 38 ± 11 years, 65% men]. Acute or chronic aortic dissection was present in 35 (95%) patients (14 and 21 patients respectively). Two (5%) patients had an aneurysm without dissection. Malperfusion syndrome was present in 4 patients. Twenty-nine (78%) patients had history of aortic surgical interventions. The 30-day and in-hospital mortality amounted to 8 and 14% respectively. False lumen exclusion was present in 73% in stented segment in last postoperative CT. The overall 5-year survival was 71% and freedom from reintervention downstream was 58% at 5 years. Of the nine patients who required reintervention for distal aortic disease, one patient died.

CONCLUSIONS

FET operation for patients with MFS can be performed with acceptable mortality and morbidity. In long-term follow-up no reinterventions on the aortic arch were required. FET allows for easier second stage operations providing platform for surgical and endovascular reinterventions.

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.

Kinking of Frozen Elephant Trunk Hybrid Prostheses: Incidence, Mechanism, and Management

Introduction

Kinking of the Frozen Elephant Trunk (FET) stent graft is one of the most devastating complications of the FET procedure. It can present post-operatively with reduced arterial pressures in the lower limbs and intermittent claudication. However, it can also be visualized intra-operatively by the surgeons. Unresolved kinking of the stent graft can result in intraluminal thrombus formation and subsequent multi-organ septic emboli.

Aims

The main scope of this review is to collate, summarize and present all the evidence in the literature on kinking of FET stent grafts.

Methods

We carried out a comprehensive literature search on multiple electronic databases including PubMed, EMBASE, Ovid, and Scopus to collate all research evidence on the incidence, mechanism, and management of FET graft kinking.

Results

Incidence of kinking is variable, ranging from 0% to 8% in the literature, with varying rates associated with each stent graft type. The Thoraflex Hybrid^TM prosthesis seemed to be the most commonly used and superior graft, and out of all the 15 cases of kinking reported in the literature, 5 (33.3%) were associated with just the Frozenix graft which had the highest incidence. There are multiple theories regarding the mechanism of kinking, including the direction of blood flow, the length of the stent grafts used, and the position of the prosthesis in relation to the flexure of the aorta. Multiple reparative management techniques have been suggested in the literature and include total endovascular repair, open repair, balloon dilatation, and deploying a second stent graft.

Conclusion

Graft kinking is one of the most critical complications of the FET technique. Its life-threatening sequelae warrant appropriate follow-up of these patients post-operatively, in addition to time management if kinking is suspected. Given the limited evidence in the literature, future studies should incorporate graft kinking into their outcomes reporting.

“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.

A Novel Sutureless Integrated Stented (SIS) Graft Prosthesis for Type A Aortic Dissection: A Pilot Study for a Prospective, Multicenter Clinical Trial

AIMS

Various kinds of surgical strategies and prostheses have been advocated to improve short-term and long-term outcomes in type A aortic dissection (TAAD). Large-scale repair of the pathological aorta is hard to generalize due to complex procedures. We aimed to investigate the performance, effectiveness and safety of a novel Sutureless Integrated Stented (SIS) graft prosthesis in TAAD patients undergoing total arch replacement (TAR) and frozen elephant trunk (FET) implantation surgery.

METHODS

All patients admitted to Fuwai Hospital were prospectively screened. Urgent or scheduled surgery was arranged for eligible patients. The primary endpoint was operative mortality. Key secondary endpoints included stroke, spinal cord injury, unexpected aortic reoperation, and 1-year survival. Discharged patients were followed up with computed tomography angiography and transthoracic echocardiography at 3 months, 6 months, and 1 year after surgery. Performance, effectiveness and safety analyses were performed in those patients.

RESULTS

Between August 1 and September 3, 2020, ten TAAD patients were enrolled in this study and successfully implanted with the SIS graft prosthesis. The median (IQR) age was 56.50 (43.75, 66.75) years (range from 31 to 75), and seven patients were male (70.0%). All patients underwent ascending aorta replacement + TAR + FET and additional procedures when necessary. The median (IQR) operation time, cardiopulmonary bypass time and cross clamp time were 270.50 (218.50, 312.50), 110.00 (88.00, 125.75), 69.50 (51.25, 82.75) min, respectively. Of note, the median (IQR) circulatory arrest time was 9.00 (8.00, 9.00) min (range from 4 to 12). The median (IQR) lowest nasopharyngeal temperature was 26.75 (25.98, 27.67) °C. Follow-up was 100% completed. During the 1-year follow-up, no patients died, no severe adverse events occurred, and rate of freedom from aortic reintervention was 100%.

CONCLUSIONS

The SIS graft prosthesis was implanted in a novel sutureless way, which simplified the surgical procedure, shortened the circulatory arrest time and avoided deep hypothermia. The preliminary clinical outcomes and follow-up outcomes demonstrated the effectiveness and safety of this prosthesis. A large-scale trial is being conducted to further assess these findings.

A single-center experience in the use of hybrid techniques for thoracic aortic pathology

The hybrid method of treating thoracic aortic pathology is devoid of the disadvantages of traditional open surgery and, at the same time, has a broader range of applications than the endovascular method. From 2014 to 2019, we researched 122 patients with thoracic aortic pathology treated with the hybrid method (open surgery with thoracic endovascular aortic repair (TEVAR) at the National M. Amosov Institute of Cardiovascular Surgery National Academy of Medical Science of Ukraine. In the general group, 34 patients had a descending aortic aneurysm without dissection or rupture; 71 patients had an aortic dissection (10 - acute, 9 - subacute, 52 - chronic), penetrating aortic ulcer (PAU) - 7, thoracoabdominal aneurysm (Crawford I-II) - 4, isolated aortic arch aneurysm - 2, residual enlargement aorta after previous ascending aortic grafting causing type A acute aortic dissection (TAAD) - 3, primary aortic thrombosis - 1. Patients admitted as elective surgery candidates had switched aortic arch vessels (debranching) in the first stage and TEVAR in the second stage. For emergencies (aortic rupture with uncontrolled bleeding, malperfusion syndrome), TEVAR operation was performed first. Long-term results of treatment after three and six months are satisfactory. The hybrid technique of aortic arch treatment using modern minimally invasive technologies can eliminate the pathology in the most dangerous segment of the main artery of the body, providing a reasonable level of hospital mortality - 4.2%, and a small number of neurological complications.

Successful one-stage operation for type B acute intramural hematoma with descending aortic rupture

A 76-year-old man who complained of back pain was referred to our hospital. Computed tomography revealed an intramural hematoma with a descending aortic rupture. Total arch replacement with the frozen elephant trunk technique and thoracic endovascular aortic repair was performed emergently in one stage. The patient was discharged without symptoms.

Early and Long-Term Follow-Up for Chronic Type B and Type Non-A Non-B Aortic Dissection Using the Frozen Elephant Trunk Technique

Background: This study aimed to evaluate the early and long-term outcomes of a single center using a frozen elephant trunk (FET) procedure for chronic type B or non-A non-B aortic dissection.

Methods: From February 2009 to December 2019, 79 patients diagnosed with chronic type B or non-A non-B aortic dissection who underwent the FET procedure were included in the present study. We analyzed operation mortality and early and long-term outcomes, including complications, survival and interventions.

Results: The operation mortality rate was 5.1% (4/79). Spinal cord injury occurred in 3.8% (3/79), stroke in 2.5% (2/79), and acute renal failure in 5.1% (4/79). The median follow-up time was 53 months. The overall survival rates were 96.2, 92.3, 88.0, 79.8, and 76.2% at 1/2, 1, 3, 5 and 7 years, respectively. Moreover, 79.3% of patients did not require distal aortic reintervention at 7 years. The overall survival in the subacute group was superior to that in the chronic group (P = 0.047).

Conclusion: The FET technique is a safe and feasible approach for treating chronic type B and non-A non-B aortic dissection in patients who have contraindications for primary endovascular aortic repair. The technique combines the advantages of both open surgical repair and endovascular intervention, providing comparable early and long-term follow-up outcomes and freedom from reintervention.

Risk factor analysis of clinical outcomes of total aortic arch replacement and frozen elephant trunk with aortic balloon occlusion

Background

Total aortic arch replacement (TAR) with frozen elephant trunk (FET) requires hypothermic circulatory arrest (HCA) for 20 min, which increases the surgical risk. We invented an aortic balloon occlusion (ABO) technique that requires 5 min of HCA on average to perform TAR with FET and investigated the possible merit of this new method in this study.

Methods

This retrospective study included consecutive patients who underwent TAR and FET (consisting of 130 cases of ABO group and 230 cases of conventional group) in Fuwai Hospital between August 2017 and February 2019. In addition to the postoperative complications, the alterations of blood routine tests, alanine transaminase (ALT) and aspartate transaminase (AST) during in-hospital stay were also recorded.

Results

The 30-day mortality rates were similar between ABO group (4.6%) and conventional group (7.8%, P = 0.241). Multivariate analysis showed ABO reduced postoperative acute kidney injury (23.1% vs. 35.7%, P = 0.013) and hepatic injury (12.3% vs. 27.8%, P = 0.001), and maintained similar cost to patients (25.5 vs. 24.9 kUSD, P = 0.298). We also found that AST was high during intensive care unit (ICU) stay and recovered to normal before discharge, while ALT was not as high as AST in ICU but showed a rising tendency before discharge. The platelet count showed a rising tendency on postoperative day 3 and may exceed the preoperative value before discharge.

Conclusions

The ABO achieved the surgical goal of TAR with FET with an improved recovery process during the in-hospital stay.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-021-01643-3.

Clinical Efficacy of Hybrid Surgery for Stanford Type A Aortic Dissection

INTRODUCTION

To evaluate the clinical efficacy of hybrid surgery for Stanford type A aortic dissection.

METHODS

Twenty-two patients with Stanford type A aortic dissection were selected. All patients had completed or undergone hybrid surgery, including extracorporeal circulation, treatment of proximal anastomosis of ascending aorta and the distal anastomosis of the ascending aorta, management of the branch vessels on the arch, aortic endovascular repair. This study analyzed the time of surgery and awake, blood transfusion during surgery, patient's drainage, complications and CTA of aorta was re-examined about one month after operation during patients follow-up.

RESULTS

All patients underwent the operation successfully. One patient died of renal failure after the operation. Two patients experienced postoperative neurological complications (anxiety and delirium). Renal function was abnormal in two patients, and one patient needed bedside blood filtration. The serum creatinine levels temporarily increased in seven patients. No stent migration was found during patient follow-up. There was no shift in the stents. The near end of the interlayer was well sealed, without leakage of contrast agent, and the false lumen near the stent was completely thrombosed. Compared with the pre-operative CTA, the true lumen was enlarged and the false lumen was reduced, and the false lumen was completely thrombosed in the proximal end and near the stent. Contrast media was seen in the false lumen.

CONCLUSION

One-stage hybrid surgery for Stanford type A aortic dissection can avoid deep hypothermic circulatory arrest, shorten operation time, reduce operation trauma, and reduce the incidence of postoperative complications. This treatment has a effective treatment effect in the short term. However, the limitations imposed by covered stent materials mean that the treatment's long-term effect is not yet clear, and further research is needed.

Spinal cord monitoring using collateral network near-infrared spectroscopy during extended aortic arch surgery with a frozen elephant trunk

The true incidence of spinal cord injury associated with modern hybrid extended arch/descending aortic procedures utilizing a frozen elephant trunk (fET) remains unclear, and it is estimated with ~5-8%. Prolonged distal arrest without sufficient hypothermic protection as well as extended coverage of segmental arteries have been suggested to cause this complication, previously uncommon in open arch surgery. Recently, extensive clinical and experimental research led to the implementation of a new method of collateral network near-infrared spectroscopy (cnNIRS) to non-invasively monitor spinal cord oxygenation in the setting of extensive thoracoabdominal aortic repair. To date, limited experience with this method during arch procedures exists. Based on recent experiments regarding the optimal cnNIRS optode placement, we used this method for the first time during an fET procedure to document mid-thoracic paraspinous oxygenation levels.

PIV Analysis of Haemodynamics Distal to the Frozen Elephant Trunk Stent Surrogate

PURPOSE

The Frozen Elephant Trunk (FET) stent is a hybrid endovascular device that may be implemented in the event of an aneurysm or aortic dissection of the aortic arch or superior descending aorta. A Type 1B endoleak can lead to intrasaccular flow during systole and has been identified as a known failure of the FET stent graft. The purpose was to develop in-vitro modelling techniques to enable the investigation of the known failure.

METHODS

A silicone aortic phantom and 3D printed surrogate stent graft were manufactured to investigate the haemodynamics of a Type 1B endoleak. Physiological pulsatile flow dynamics distal to the surrogate stent graft were investigated in-vitro using Particle Image Velocimetry (PIV).

RESULTS

PIV captured recirculation zones and an endoleak distal to the surrogate stent graft. The endoleak was developed at the peak of systole and sustained until the onset of diastole. The endoleak was asymmetric, indicating a potential variation in the phantom artery wall thickness or stent alignment. Recirculation was identified on the posterior dorsal line during late systole.

CONCLUSIONS

The identification of the Type 1B endoleak proved that in-vitro modelling can be used to investigate complex compliance changes and wall motions. The recirculation may indicate the potential for long term intimal layer inflammatory issues such as atherosclerosis. These results may aid future remediation techniques or stent design. Further development of the methods used in this experiment may assist with the future testing of stents prior to animal or human trial.

An elephant trunk stent graft strayed into the false lumen leading to a death during the Sun's operation: A case report

Type A aortic dissection (AD) is a critical and severe disease with high mortality. The Sun's operation is a standard surgical method for this kind of disease at present. For the procedure, an elephant trunk stent is inserted into the true lumen of the descending aorta and the aortic arch is replaced. A patient was admitted to the First Hospital of Lanzhou University due to sudden chest and back pain for 6 days. Computed tomography angiography (CTA) showed type A AD. Ascending aorta replacement, Sun's operation, and ascending aorta to right femoral artery bypass grafting were performed. After surgery, the patient's condition was worsened. The digital subtraction angiography (DSA) showed the elephant trunk stent was inserted into the false lumen of AD, leading to the occlusion of the large blood vessel at the distal part of the abdominal aorta and below. Although we performed intima puncture and endovascular aortic repair, the patient was still dead.

Comparison between Arch Zones in Modified Frozen Elephant Trunk Procedure for Complex Thoracic Aortic Diseases

Introduction

The aim of this study is to compare postoperative outcomes and follow-up of two different modifications facilitating surgical technique of frozen elephant trunk (FET) procedure for complex thoracic aortic diseases - zone 0 (fixation with total arch debranching) and zone 3 (fixation with islet-shape arch repair).

Methods

From May 2012 to December 2018, data were collected from 139 patients who had been treated with FET procedure for complex thoracic aortic diseases. According to Ishimaru arch map, patients with proximal anastomotic site of hybrid graft at zone 0 and zone 3 were grouped as Group A (n=58, 41.7%) and Group B (n=81, 58.3%), respectively. Mean age of study population was 54.7±11.4 years, and 111 patients were male (79.9%).

Results

In-hospital mortality was observed in 20 (14.4%) patients (n=12, acute type A aortic dissection, and n=4, previous aortic dissection surgery). There was no significant difference between both groups in terms of in-hospital mortality. Four patients from Group A and three patients from Group B had permanent neurological deficit (P=0.32). Three patients from both groups had transient spinal cord ischemia (P=0.334). Although mean total perfusion time was longer in Group A, duration of visceral ischemia, when compared with Group B, was shorter (P<0.001). Five-year survival rate was 82.8% in Group A and 81.5% in Group B (P=0.876).

Conclusion

FET procedure is a feasible repair technique in the treatment of complex aortic diseases, providing satisfactory early results. Because of its advantageous aspects, zone 0 fixation with debranching is the preferred technique in our clinic.

Early and mid-term outcome of frozen elephant trunk using spinal cord protective perfusion strategy for acute type A aortic dissection

OBJECTIVE

This study aimed to evaluate the prevalence of spinal cord injury in total arch replacement with frozen elephant trunk for acute type A aortic dissection using our spinal cord protection technique.

METHODS

Between January 2013 and December 2017, 33 patients underwent total arch replacement with frozen elephant trunk for acute type A aortic dissection (mean age 67.9 ± 13.3 years). Our spinal cord protection technique involved maintaining extracorporeal circulation through the left subclavian artery in all procedures, using aortic occlusion balloon during distal anastomosis, and inserting frozen elephant trunk above Th 8 with transesophageal echocardiographic guidance. Computed tomography was performed within 1-2 weeks, 12 months, and 36 months postoperatively. We compared the degree of thrombosis of the descending aorta between preoperation and early postoperative period by Fisher's exact test. Moreover, we evaluated postoperative mortality and mobility (including spinal cord injury) at follow-up.

RESULTS

The operative mortality within 30 days was 6.1%. Neither paraplegia nor paraparesis was noted. We observed significant thrombosis of the false lumen at the distal arch and aortic valve level of the descending aorta in postoperative early term period (p < 0.01). At mid-term follow-up (mean 33.9 months), survival probability and 3-year freedom from reoperation rates were 93.9 ± 4.1% and 95.0 ± 4.9%, respectively.

CONCLUSIONS

The frozen elephant trunk technique with our spinal protection strategy provides good postoperative outcomes. Our strategy can maintain spinal cord perfusion without complete ischemia time even during lower body ischemia time. Implementation of our spinal protection strategy will help prevent spinal cord injury and dilated downstream aorta.

Which is the Optimal Frozen Elephant Trunk? A Systematic Review and Meta-Analysis of Outcomes in 2161 Patients Undergoing Thoracic Aortic Aneurysm Surgery Using E-vita OPEN PLUS Hybrid Stent Graft versus Thoraflex™ Hybrid Prosthesis

Objective

To systematically review the rate of morbidity and mortality associated with the use of E-vita hybrid stent graft and ThoraflexTM in patients undergoing complex aortic surgery.

Methods

A comprehensive search was undertaken among the four major databases to identify published data about E-vita or Thoraflex™ in patients undergoing repair of thoracic aortic aneurysms.

Results

In total, 28 papers were included in the study, encompassing a total of 2,161 patients (1,919 E-vita and 242 Thoraflex™). Patients undergoing surgery with E-vita or Thoraflex™ were of similar age and sex. The number of patients undergoing non-elective repair with Thoraflex™ was higher than with E-vita (35.2% vs. 28.7%, respectively). Cardiopulmonary bypass time was associated with increasing mortality in E-vita patients, however a meta-analysis of proportions showed higher 30-day mortality, permanent neurological deficit, and one-year mortality for Thoraflex™ patients. Direct statistical comparisons between E-vita and Thoraflex™ was not possible due to heterogeneity of studies.

Conclusion

Although there are limited studies available, the available data suggests that mortality and morbidity are lower for the E-vita device in thoracic aortic aneurysm surgery than for Thoraflex™. Long-term data of comparative studies do not yet exist to assess viability of these procedures.

The strategy of cardiopulmonary bypass for total aortic arch replacement and the frozen elephant trunk technique with aortic balloon occlusion

Objective

To investigate the use of the aortic balloon occlusion technique to assist total aortic arch replacement (TAR) with frozen elephant trunk (FET) to shorten the lower body circulatory arrest (CA) time and raise the nadir temperature during cardiopulmonary bypass.

Methods

This retrospective study reviewed consecutive patients that underwent aortic balloon occlusion to assist TAR with FET and patients that received conventional TAR with FET procedures. Preoperative characteristics, perioperative characteristics and postoperative outcomes were compared between the two groups.

Results

The study included130 patients treated with aortic balloon occlusion and 230 patients treated with conventional TAR with FET. The 30-day mortality rate was similar between the aortic balloon occlusion and conventional groups (4.62% versus 7.83%, respectively). Multivariate analysis showed that aortic balloon occlusion reduced the incidence of acute kidney injury, hepatic injury and red blood cell transfusion. The application of aortic balloon occlusion reduced the mean ± SD CA time from 17.24 ± 4.36 min to 6.33 ± 5.74 min, with the target nadir nasal temperature being increased from 25°C to 28°C.

Conclusion

The aortic balloon occlusion technique achieved significant improvements in reducing complications, but this did not translate into lower 30-day mortality.

Frozen elephant trunk with Frozenix prosthesis

This paper presents the clinical applications of the Japanese-made frozen elephant trunk (FET, Frozenix®). The historical aspects of FET development, manufacture and structure of Frozenix, video images of a representative case, and a summary of a multi-centre Japanese Frozenix study, J-ORCHESTRA, are discussed.

Hybrid arch frozen elephant trunk repair: evidence from the Canadian Thoracic Aortic Collaborative

Background

The frozen elephant trunk (FET) technique has become an increasingly popular strategy for aortic reconstruction in the setting of extensive thoracic aortic aneurysms or dissections. The objective of this study is to report on the Canadian experience with the FET technique in both the elective and emergent settings.

Methods

A total of 167 consecutive patients (mean age 65±13 years, 30% female, 25% re-operation) underwent elective (70%) and non-elective (30%) aortic arch reconstruction with the FET technique between May 2008 and October 2019 in six centers of the Canadian Thoracic Aortic Collaborative (CTAC). In-hospital clinical endpoints and early imaging endpoints were prospectively collected and analyzed.

Results

All 167 patients underwent successful FET implantation. In-hospital mortality occurred in 14 patients (8%), stroke occurred in 22 patients (13%) and temporary and permanent spinal cord ischemia (SCI) occurred in 6 (3.6%) and 3 (1.8%) patients, respectively. Prolonged mechanical ventilation was required in 35 patients (21%), renal failure requiring dialysis in 14 patients (8%) and atrial fibrillation in 59 patients (36%). The median hospital and intensive care unit (ICU) lengths of stay were 3 [interquartile range (IQR): 1, 6] and 10 (IQR: 7, 17) days, respectively. The rate of type 1A endoleak was 3.6%, with the lowest rate in patients who underwent a total arch replacement with a hybrid FET graft (0%) and the highest among patients who had a hemiarch with antegrade thoracic endovascular aortic repair (TEVAR) deployment (25%). The rate of other types of endoleak and stent complications was comparatively low.

Conclusions

The early CTAC experience with the FET operation demonstrates technical feasibility and good early clinical outcomes in elective and emergent patients. Further analysis is required to explore variations in technique and their potential impact on early and late outcomes.

Risk factors for spinal cord injury in patients undergoing frozen elephant trunk technique for acute aortic dissection

BACKGROUND

The purpose of this study was to evaluate the risk factors for spinal cord injury (SCI) in patients with acute aortic dissection undergoing surgery with frozen elephant trunk technique (FET).

METHODS

From December 2014 to February 2018, 17 patients with acute aortic dissection underwent surgical treatment of the aortic arch with FET. SCI occurred in 3 patients. Risk factors for SCI were evaluated.

RESULTS

Mean age of the patients was 56 years and 88.2% were male. The ratio of true lumen to total aortic diameter at the level of carina (before: 0.48 vs. after: 0.75, P < 0.001), aortic valve (before: 0.47 vs. after: 0.67, P = 0.001), and celiac artery (before: 0.48 vs. after: 0.68, P = 0.003) increased after surgery. There were no significant differences in perioperative minimum hemoglobin level and postoperative mean arterial pressure between patients with and without SCI. However, patients with SCI had higher creatinine level before surgery (SCI: 1.32 mg/dL vs. no SCI: 0.81 mg/dL, P = 0.023). Although there was no difference in number of patent intercostal arteries before surgery, those originating from the true lumen were fewer in patients with SCI (SCI: 2.7 vs. no SCI: 8.6, P = 0.021). Furthermore, with entry closure, significant decrease in patency was observed in intercostal arteries originating from the false lumen (before: 3.1 vs. after: 1.0, P < 0.001).

CONCLUSION

FET was useful in entry closure. However, FET in patients with higher creatinine level and those who may have significant spinal cord perfusion from the false lumen could be a risk factor for postoperative SCI.

Off pump hybrid extra-anatomic techniques for aortic arch repair-own experience

Background

Treatment of the aortic arch pathologies is technically challenging. In this study we assess early and late outcomes of hybrid aortic arch repairs that comprise extra-anatomic surgical procedures completed by thoracic endovascular interventions [thoracic endovascular aortic repair (TEVAR)].

Methods

Since 2007, 21 patients (8 women and 13 men) with a median age of 48 years have undergone hybrid procedures for aortic arch pathologies. All of them were treated without cardio-pulmonary bypass. All survivors were followed up regularly and imaging examination were performed. A technical success, procedural complications as well as the early and late mortality and morbidity rates were evaluated.

Results

All patients survived surgery and TEVAR was technically successful in all of them. However, 2 individuals died (in-hospital mortality rate 9.5%) during in-hospital stay, both due to multi-organ failure (MOF). Additionally, one patient developed symptoms of cerebral stroke, another one of spinal cord ischemia. During the follow-up that ranged from 6 to 118 months and was completed by 100% of the survivors, one patient died 3 years after procedure because of sepsis (aorto-oesophageal fistula prior to intervention) and late vascular graft occlusions were noted in three cases.

Conclusions

Hybrid procedures on the aortic arch that comprise surgical and endovascular interventions has become an attractive and safe therapeutic option with acceptable mortality and morbidity rate. They may be considered as a method of choice in treatment of the elderly and high-risk patients.

Aortic arch replacement with frozen elephant trunk technique - a single-center study

BACKGROUND

The frozen elephant trunk (FET) technique was developed to facilitate the two-stage surgery of extensive pathologies of the thoracic aorta and is now routinely applied in acute and chronic aortic syndromes.

METHODS

From 11/2006 to 07/2017, 68 patients underwent aortic arch repair using the FET technique. Patients received either the Jotec E-vita Open graft (n = 57) or the Vascutek Thoraflex hybrid prosthesis (n = 11). Both, group 1 (acute aortic dissection type A and B; symptomatic penetrating aortic ulcer) and group 2 (aortic aneurysm; chronic aortic dissection) included 34 patients each.

RESULTS

Early mortality was 13.2% (14.7% in group 1 vs. 11.7% in group 2, p = 0.720). Neurological complications occurred in 12 patients (17.6%) (stroke: 8.8 vs. 11.7%; p = 0.797 and spinal cord injury: 8.8 vs. 5.9%; p = 0.642 in groups 1 vs. 2 respectively). Cardiopulmonary bypass time and cross clamp time were significantly longer in group 1 (252.2 ± 73.5 and 148.3 ± 34 min vs. 189.2 ± 47.8 and 116.3 ± 34.5 min; p <  0.001). The overall 1-, 3- and 7-year-survival was 80.9, 80.9 and 74.2% with no significant differences between groups 1 and 2. Expansion of true lumen after FET implantation was significant at all levels in both groups for patients with aortic dissection. One-, 3-, and 7-year-freedom from secondary (re-)intervention for patients for aortic dissection was 96.9, 90.2 and 82.7% with no significant differences between groups 1 and 2; p = 0.575.

CONCLUSION

The FET technique can be applied in acute aortic syndromes with similar risks regarding adverse events or mortality when compared to chronic degenerative aortic disease. Postoperative increase in true lumen diameter mirrors decrease of false lumen diameter, goes along with favorable midterm outcome and prolongs freedom from secondary interventions in acute aortic dissection.

Spinal cord injury following aortic arch replacement

PURPOSE

Postoperative spinal cord injury is a devastating complication after aortic arch replacement. The purpose of this study was to determine the predictors of this complication.

METHODS

A group of 254 consecutive patients undergoing aortic arch replacement via median sternotomy, with (n = 78) or without (n = 176) extended replacement of the upper descending aorta, were included in a risk analysis. The frozen elephant trunk technique was used in 46 patients. The patients' atherothrombotic lesions (extensive intimal thickening of > 4 mm) were identified from computed tomography images.

RESULTS

Complete paraplegia (n = 7) and incomplete paraparesis (n = 4) occurred immediately after the operation (permanent spinal cord injury rate, 1.97%; transient spinal cord injury rate, 2.36%). A multivariable logistic regression analysis identified the use of the frozen elephant trunk technique (odds ratio 36.3), previous repair of thoracoabdominal aorta or descending aorta (odds ratio 29.4), proximal atherothrombotic aorta (odds ratio 9.6), chronic obstructive lung disease (odds ratio 7.1) and old age (odds ratio 1.1) as predictors of spinal cord injury (p < 0.0001, area under curve 0.93).

CONCLUSIONS

Spinal cord injury occurs with a non-negligible incidence following aortic arch replacement. The full objective assessment of the morphology of the whole aorta and the recognition of the risk factors are mandatory.

Mini open stent grafting with half sternotomy for aortic arch aneurysm

BACKGROUND

Open stent grafting is an alternative of graft replacement and thoracic endovascular aortic repair for aortic arch aneurysm. We have performed open stent grafting with half sternotomy (mini-OSG) to reduce in-hospital stay and recovery time of patients and herein report seven cases of mini-OSG for aortic aneurysm and dissection.

CASE PRESENTATION

The patients' mean age was 66 years. Cardiopulmonary bypass was performed conventionally, and an open stent graft was inserted via an aortotomy on the aortic arch during circulatory arrest. No mortality occurred. The mean operation time was 387 min, and the mean blood loss was 587 ml. The patients were weaned from the ventilator 7.1 h postoperatively. No pseudoaneurysm or endoleakage was observed during the 2- to 20-month follow-up.

CONCLUSIONS

Mini-OSG might be less invasive, although further studies and intensive follow-up are needed.

Single Low-Volume Center Experience with Frozen Elephant Trunk in Acute Type A Aortic Dissections

BACKGROUND

 Acute Type A aortic dissection (AAAD) is a surgical emergency. In patients with arch and descending aorta involvement (DeBakey Type I), a total aortic arch replacement with frozen elephant trunk (FET) could favor false lumen thrombosis and improve long-term results. The authors hereby present their experience with this technique in a single low-volume center, to assess whether the technique is feasible to treat such disease.

METHODS

 From January 2011 to December 2016, 43 patients with AAAD were operated on in the authors' institution, which carries out 300 to 350 annual procedures. Among these, 12 patients with an intimal tear in the aortic arch and/or proximal descending aorta received a FET procedure (10 males, age 57 years). Concomitant procedures were aortic valve replacement (42%), Bentall (25%), and aortic valve repair (17%).

RESULTS

 Cardiopulmonary bypass, cardiac arrest, and circulatory arrest times were 235 ± 43, 171 ± 33, and 75 ± 20 minutes, respectively. The operative mortality was 16.7% (n = 2). Stroke and re-thoracotomy for bleeding occurred in 8% (n = 1) and 8% (n = 1), respectively. There was no spinal cord injury. Follow-up was 36.1 months. During follow-up, no patients died or required a reoperation on the downstream aorta.

CONCLUSION

 Although all patients were operated on in a low-volume center, the results with FET in AAAD are acceptable. Even though this technique demands high technical skills, it is a promising approach in patients with acute aortic dissection.

Early and mid-term results of frozen elephant trunk procedure for acute type A aortic dissection

BACKGROUND

This study aims to investigate the early and mid-term results of total thoracic aorta repair with E-vita OPEN PLUS stent graft, which we used to remove the residual false lumen and prevent late-term complications in patients with acute type A aortic dissections.

METHODS

The study included 41 patients (29 males, 12 females; mean age 51.9±10.4 years; range, 30 to 77 years) who underwent total thoracic aorta repair with frozen elephant trunk stent graft for acute type A aortic dissection between November 2013 and November 2017. The reduction in false lumen size and thrombosis were evaluated by repeated computed tomographyangiography on 10th day and third, sixth, and 12th months.

RESULTS

Six patients (14.6%) were lost during hospital stay and one patient (2.4%) was lost during the follow-up period. Frozen elephant trunk stent graft"s distal end at descending aorta ended at T6, T7, and T8 levels in 15 (36.6%), 21 (51.2%), and five (12.2%) patients, respectively. The supra-aortic vessels were re-implanted separately in 21 (51.2%) or as island in 20 (48.8%) patients. Transient paraparesis (spinal cord ischemia) was observed in only one patient (2.4%), while permanent neurologic deficit (stroke or coma) was observed in two patients (4.9%). Mean duration of follow-up was 26.5±20.5 months. Computed tomography-angiography at first month showed that false lumen became thrombosed at rates of 93.9% and 54.5% at pulmonary trunk and diaphragmatic level, respectively.

CONCLUSION

We believe that total arcus repair in acute type A aortic dissection treatment with single-session frozen elephant trunk technique by ensuring early false lumen thrombosis is safe and successful.

One-stage hybrid aortic repair using the frozen elephant trunk in acute DeBakey type I aortic dissection

Background

The extent of emergent surgery for acute DeBakey type I aortic dissection is discussed controversial. The frozen elephant trunk (FET) technique in addition to ascending and arch repair promotes aortic remodelling in the descending aorta and thus may provide superior long-term results in terms of less secondary re-interventions and reduced mortality linked to the downstream aorta.

Methods

Between October 2009 and December 2016, a total of 72 patients underwent emergent hybrid aortic repair using the FET for acute DeBakey type I aortic dissection at our centre. Data were analysed from our prospectively collected database and clinical and imaging mid-term follow-up was obtained.

Results

Implant success was 98.6% with an overall 30-day-mortality of 15.3%. New postoperative stroke was seen in 2.8%, new spinal cord injury in 4.2%. In follow-up (mean 37.8±21.2 months) cumulative survival was 75.0% with freedom from distal reintervention in 96.7% and aortic remodelling rate in the descending aorta in 96.5%.

Conclusions

Hybrid aortic repair using the FET in acute DeBakey type I aortic dissection does not elevate the perioperative risk of mortality and provides excellent aortic remodelling with low distal re-intervention rate in mid-term follow-up.

Long-term survival and related outcomes for hybrid versus traditional arch repair-a meta-analysis

Background

Surgical interventions for aortic aneurysm and dissection remain associated with high risk of mortality and morbidity. Advances in operative techniques have led to a variety of options for the cardiac surgeon, including endovascular and hybrid approaches. Debate remains over which of these techniques provide optimal outcomes for the patient. The present systematic review and meta-analysis aims to evaluate long term patient survival and identify short-term outcomes for conventional (open) aortic arch repair and hybrid aortic arch repair (HAR).

Methods

An electronic literature search was conducted according to predefined inclusion criteria for hybrid and conventional aortic arch repair surgery. Digitized survival data was extracted from identified studies' Kaplan-Meier curves and used to re-create individual patient data for aggregated survival analysis. Post-operative morbidity and mortality were analyzed using random-effects model meta-analysis.

Results

Nine studies were included, containing 841 hybrid arch repair and 1,182 conventional arch repair patients. Pooled Kaplan-Meier analysis of all patients demonstrated higher survival in hybrid arch repair patients than conventional arch repair patients, however, this was noted to be sensitive to results from a particular study. Overall results showed for the hybrid repair cohort, survival at 1, 2, 3, 5 and 7 years was 87%, 85%, 83%, 78% and 75%, respectively. Survival in the conventional repair cohort at 1, 2, 3, 5 and 7 years was 84%, 82%, 80%, 75% and 71%, respectively. Statistically significant findings from meta-analysis showed hybrid arch repair was associated with lower risk of re-operation for bleeding, while conventional arch repair was associated with reduced risk of spinal cord injury.

Conclusions

Pooled Kaplan-Meier analysis of all studies showed long-term survival outcomes for hybrid and conventional aortic arch repair patients are heterogeneous and sensitive to the results of particular studies. Superior results from particular centres and the low number of comparative studies mean that more data is required to make definitive findings with regards to the long-term survival outcomes of either procedure. Hybrid arch repair was associated with lower risk of re-operation for bleeding, while conventional arch repair was associated with lower risk of spinal cord injury. Surgeons should consider their own center's experience and patient suitability when deciding between hybrid or conventional aortic repair techniques.

Subcellular Energetics and Metabolism: Potential Therapeutic Applications

Part I of this review discussed the similarities between embryogenesis, mammalian adaptions to hypoxia (primarily driven by hypoxia-inducible factor-1 [HIF-1]), ischemia-reperfusion injury (and its relationship with reactive oxygen species), hibernation, diving animals, cancer, and sepsis, and it focused on the common characteristics that allow cells and organisms to survive in these states. Part II of this review describes techniques by which researchers gain insight into subcellular energetics and identify potential future tools for clinicians. In particular, P nuclear magnetic resonance to measure high-energy phosphates, serum lactate measurements, the use of near-infrared spectroscopy to measure the oxidation state of cytochrome aa3, and the ability of the protoporphyrin IX-triplet state lifetime technique to measure mitochondrial oxygen tension are discussed. In addition, this review discusses novel treatment strategies such as hyperbaric oxygen, preconditioning, exercise training, therapeutic gases, as well as inhibitors of HIF-1, HIF prolyl hydroxylase, and peroxisome proliferator-activated receptors.

Hybrid repair of aortic arch aneurysms: a comprehensive review

Open total arch replacement (TAR) has become safer with refinements in cerebral protection techniques. The frequent extension of aortic arch aneurysms into the descending thoracic aorta customarily requires a two-staged conventional elephant trunk procedure, carrying relatively high mortality and morbidity risks and high rates of rupture in the interval between the two open surgeries. The technical demands and invasive nature of TAR has therefore precluded many high-risk patients from being surgical candidates for aneurysm repair. As a result, hybrid techniques and approaches to the aortic arch have become common since the adoption of thoracic endovascular aortic repair (TEVAR) and advancement in the commercial grafts that are available. The results of hybrid aortic arch repairs have been encouraging, though with higher rates of re-interventions than TAR and variable reported rates of stroke and spinal cord ischemia. The aim of this publication is to review the current literature on hybrid repair of aortic arch aneurysms.

Radiopaque Ruler-Guided Frozen Elephant Trunk Technique

Frozen elephant trunk (FET) technique combines open surgery and endovascular repair for extensive thoracic aortic aneurysms. When a FET is inserted into the descending thoracic aorta, it is difficult to confirm its proper positioning. Here we report a radiopaque ruler-guided FET technique. On the basis of preoperative computed tomography, we create a roadmap which shows the relationship between the descending thoracic aorta and vertebrae. During surgery, a radiopaque ruler placed beneath the patient's back provides the accurate target position under fluoroscopy. Our technique is effective to prevent spinal cord injury because it avoids an overly deep implantation of a FET.

Outcome of frozen elephant trunk technique for acute type A aortic dissection: as systematic review and meta-analysis

Acute aortic dissections of Stanford type A require emergency surgery repair and present challenges to surgeons. The frozen elephant technique is one of several approaches used to treat aortic arch dissection. The purpose of this meta-analysis was to investigate the clinical effectiveness of the frozen elephant technique for treating acute type A aortic dissection.Medline, Cochrane, Google Scholar, and ClinicalTrials.gov databases were searched up to March 31, 2014, for studies that assessed the use of frozen elephant trunk technique for treating acute type A aortic dissection. The primary outcome was in-hospital mortality. Secondary outcomes included rate of stroke, spinal cord injury, renal failure, and reoperations for bleeding.Eleven studies were included in the analysis that encompassed 881 patients. The mean age ranged from 45.4 to 66.8 years, and the proportion of the population that was male ranged from 45 to 85%. The overall in-hospital mortality rate was 8%. The rate of stroke, spinal cord injury, renal failure, and frequency of reoperations for bleeding were 3, 4, 5, and 5, respectively. Sensitivity analysis indicates that the findings are robust and there was no publication bias.These findings indicate that the frozen elephant techniques does not bring unacceptable mortality or morbidity risk for treating acute type A aortic dissection.

Open surgical repair for chronic type B aortic dissection: a systematic review

BACKGROUND

The treatment of chronic type B aortic dissection (CBAD) remains complicated. Thoracic endovascular aortic repair (TEVAR) has supplanted open surgical repair (OSR) as the preferred surgical treatment for CBAD. Despite TEVAR's superior short-term results, much less is understood about its long-term outcomes. As much of the understanding of OSR originates from historical report, contemporary series, with modern surgical techniques and technologies, may present an alternative to TEVAR. The present systematic review will assess the short- and long-term outcomes of historic and contemporary series of OSR for CBAD.

METHODS

Electronic searches were performed using six databases from their inception to March 2014. Relevant studies with OSRs for chronic type B dissection were identified. Data were extracted by two independent reviewers and analyzed according to predefined clinical endpoints. Studies were sub-classified into the pre-endovascular (historic series) and endovascular era (contemporary series) depending on whether the majority of cases were performed after 1999.

RESULTS

Nineteen studies were identified for inclusion for quantitative analysis. Pooled short-term mortality was 11.1% overall, and 7.5% in the nine contemporary studies. Stroke, spinal cord ischemia, renal dysfunction, and reoperation for bleeding were 5.9%, 4.9%, 8.1%, and 8.1%, respectively, for the contemporary series. Absolute late reintervention was identified in 13.3% of patients overall, and in 11.3% of patients in the contemporary series. Aggregated survival at 1-, 3-, 5-, and 10-years of all patients were 82.1%, 74.1%, 66.3%, and 50.8%, respectively.

CONCLUSIONS

OSR for chronic type B dissection in the contemporary era offers acceptable results. Management approaches should be considered carefully, taking into account both short-term and long-term complications. More research is required to clarify specific indications for OSR and TEVAR in chronic type B dissections.

Aortic arch replacement with frozen elephant trunk-when not to use it

Current scientific evidence suggests the frozen elephant trunk (FET) technique plays an important role in modern aortic arch repair operations, both for aneurysmal disease and acute aortic dissection. Its use in extended aneurysm is generally therapeutic, aiming for complete exclusion of the diseased descending thoracic aorta. In acute aortic dissection type A, the application of FET is more prophylactic in nature, with the aim of preventing late dilatation of the proximal descending thoracic aorta. This review will present the journey of the elephant trunk from its conception to the current available technology. By tracing the historical evolution of the FET technique and prosthesis development, we explore the challenges and limitations of evidence-based surgical research. We present data from our growing experience in aortic arch reconstruction, the results from our latest 27 patients undergoing the 4-branch FET indicating substantially reduced morbidity and mortality (0%) in this complex patient cohort.