Aortic Outcome After Implementation of a Treatment Strategy for Type B Aortic Dissection Involving the Aortic Arch

OBJECTIVE

To evaluate outcomes achieved after implementing a treatment strategy for non-A non-B (NANB) (B 1-2 D according to the latest consensus document of the Society of Vascular Surgery (SVS) and Society of Thoracic Surgeons (STS) acute aortic dissection (AAD).

METHODS

This retrospective observational study adhered to the STROBE checklist. All cases of NANB AAD (B 1-2 D) treated at our Institution between January 2016 and December 2022 were reviewed. Morbidity, mortality, aortic-related reintervention, and remodelling were analysed.

RESULTS

Among 519 cases of acute aortic syndrome, n=22 (4.2%) patients presented with NANB AAD (B 1-2 D) (n=16,72.7% men, mean age 61.5 years+/14.7). Eleven cases were managed with best medical treatment (BMT) alone. Among them, one patient (9.1%) died suddenly two days after diagnosis for aortic rupture. Frozen elephant trunk procedure (FET) was required in the remaining 11 patients: 7(31.8%) needed emergent operation for risks of impending aortic rupture/retrograde AD extension and 4(26.7%) underwent delayed surgery within a month from initial presentation. Overall, in-hospital mortality was 9.1% with both FET and BMT. At a median follow-up of 40 months (range 2 days-200 months) no other deaths occurred. A statistically significant differences in the rate of FL thrombosis (100% vs 55.5%, p=.033) and a significant positive aortic remodelling in zone 3 (p<.001) and 4 (p=0.038) were reported in operated versus medically managed patients.

CONCLUSION

The best treatment for NANB is not established. We advocate for medical stabilisation with an operative approach that favours open surgery in the acute post dissection period, promotes aortic remodelling and carries acceptable risk in centres where FET is performed routinely.

Two-Stage Surgery Using FROZENIX Partial ET for Frozen Elephant Trunk Technique and Open Descending Aortic Replacement in a Patient With Recurrent Type B Aortic Dissection and Microscopic Polyangiitis: A Case Report

The frozen elephant trunk (FET) technique, initially developed as a one-stage procedure to treat extensive thoracic aortic aneurysms, has since been adapted to address acute and chronic aortic dissections by closing entry tears and expanding the true lumen. It has become widely adopted due to its effectiveness in managing aortic diseases. We present the case of a 39-year-old female with microscopic polyangiitis (MPA) who developed recurrent type B aortic dissection accompanied by rapid expansion. The patient, a compromised host with multiple comorbidities such as glomerulonephritis, chronic renal failure, alveolar hemorrhage, and acute pancreatitis, required urgent surgical intervention. Given the complexity of her condition and the high risks associated with direct surgery, a staged approach was selected. The first stage involved using a novel FET prosthesis, the FROZENIX Partial ET (FPET), inserted via median sternotomy, followed by a left thoracotomy for non-deep hypothermic circulatory arrest (non-DHCA) descending aortic replacement. The surgery led to favorable outcomes without any major complications or sequelae. FPET offers distinct advantages in this complex scenario. Its design features a 2 cm stent-free distal section, which reduces the risk of distal stent graft-induced new entries (dSINEs) and simplifies anastomosis during the second stage of surgery. For patients with severe comorbidities and anatomical challenges that make the thoracic endovascular aortic repair (TEVAR) unsuitable, a staged open surgical approach is a viable alternative, mitigating the risks linked to DHCA. This case underscores the utility of a staged surgical approach using FPET in managing complicated chronic type B aortic dissection in patients with significant comorbidities. The FPET prosthesis facilitates effective lesion control while minimizing the risk of dSINEs and streamlining subsequent surgical procedures, presenting a promising strategy for similar complex cases.

The frozen elephant trunk technique in acute aortic dissection: the ultimate solution? An institutional experience

Objective

Acute aortic dissection remains a serious emergency in the field of cardiovascular medicine and a challenge for cardiothoracic surgeons. In the present study, we seek to compare the outcomes of different surgical techniques in the repair of type A acute aortic dissection.

Methods

Between April 2015 and May 2023, 213 patients (82 women, aged: 63.9 ± 13.3 years) with acute aortic dissection (205 type A and 8 non-A-non-B dissections) underwent surgical treatment in our department. A total of 45 patients were treated with the frozen elephant trunk (FET) technique supported by the Thoraflex™ Hybrid prosthesis, 33 received total aortic arch replacement (TAR)-standard or conventional elephant trunk-treatment, and 135 were treated with hemiarch replacement (HR). Aortic arch surgery was performed in most patients under moderate hypothermic (28°C on average) circulatory arrest, with selective antegrade cerebral perfusion through the right axillary artery.

Results

The rates of early mortality were 17.8% (38 perioperative deaths) in the whole population, 8.9% in the FET group of patients, and 33% and 17% in the TAR and HR group of patients, respectively (P-value 0.025). The rate of spinal cord injury was 2.3% (five patients), and a paresis of recurrent laryngeal occurred in 3.7% of patients (seven patients, four were treated with FET). Permanent neurological dysfunction occurred in 27 patients (12.7%). After a mean follow-up of 3 years, the rate of mid-term mortality of discharged patients was 19.4% (34 deaths: 7 FET, 4 TAR, and 23 HR) and the overall mortality rate was 33.8% [72 deaths: 11 FET (24.4%); 15 TAR (45.4%); 46 HR (34.1%)]. A total of 8 patients (17.8%) in whom FET was applied received additional endovascular treatment in the descending aorta.

Conclusions

In our institutional experience, we found that the frozen elephant trunk technique with a high-end Thoraflex Hybrid prosthesis proved its surgical suitability in the treatment of acute aortic dissection with favorable outcomes. The FET technique and our perioperative management led to comparable neurological outcomes and reduced mortality rates in these emergency cases.

Thoracic endovascular aortic repair completion following frozen elephant trunk: how it's done and device selection

INTRODUCTION

Since its introduction in the mid-1990s the frozen elephant trunk (FET) technique has quickly evolved into an effective hybrid treatment option for patients with various thoracic aortic pathologies, acute and chronic. However, a notable incidence of and risk for distal aortic reinterventions persists after the implementation of the FET device. In this review, the authors analyze the indications and outcomes of thoracic endovascular aortic repair completion following FET.

AREAS COVERED

For this review we looked not only at our own data but also searched PubMed for relevant studies, comments and current recommendations of the European Association for Cardio-Thoracic Surgery (EACTS) and the European Society for Vascular Surgery (ESVS). Additionally, we outline our approach in this 2-stage-treatment plan.

EXPERT OPINION

The treatment of acute or chronic aortic pathologies involving the aortic arch frequently requires a 2-stage treatment approach. Sometimes, a tertiary procedure is needed to fix the entire aortic pathology. Thoracic endovascular aortic repair completion following FET needs careful planning to achieve the excellent clinical outcomes that we and numerous other aortic centers have shown. Only a dedicated aortic clinic provides the long-term continuous follow-up required to identify the few patients in need of a tertiary procedure.

Frozen Elephant Trunk Procedure for Acute Type a Aortic Dissection: Analysis of Distal Aortic Remodeling According to the Society for Vascular Surgery (SVS)/Society of Thoracic Surgeons (STS) Reporting Standard

BACKGROUND

To investigate impact of frozen elephant trunk (FET) on long-term distal aortic remodeling in acute A aortic dissection (AAD) according to the latest recommended standards from the Society for Vascular Surgery (SVS)/Society of Thoracic Surgeons (STS).

METHODS

Clinical data and imaging of patients who underwent FET to treat acute AAD over the last 8 years were retrospectively reviewed. Patients were included if a pre and postoperative computed angio tomographies at least 30 days from surgery was available for comparison. Contrasted postprocessed imaging were analyzed with Aquarius iNtuition (TeraRecon Inc., Foster City, CA, USA) to analyze long-term positive aortic remodeling, false lumen thrombosis, and aortic expansion according to the SVS or STS recommendations. Secondary endpoints were the rate of in-hospital and long-term mortality, spinal cord ischemia (SCI), and aortic-related reinterventions.

RESULTS

Out of 75 patients who underwent FET for type A AAD, n = 41 (54.6%) were included. Significant positive aortic remodeling was reported in Ishimaru zone 1-4 but not in visceral or infrarenal aorta (P < 0.001), and the overall rate of false lumen thrombosis was 95.1% (n = 39). Aortic expansion rates were as follows: 4.9% in zones 1-4, 8.3% in zones 5-6, and 15% in zone 7. The rates of in-hospital mortality and long-term mortality were 7.3% (n = 3) and 9.7% (n = 4), respectively. At a median follow-up of 11 months (range 1-141, reintervention rate was 17.1%.

CONCLUSIONS

We report positive aortic remodeling of the distal thoracic aorta in patients who underwent FET for acute AAD according to the SVS or STS reporting standards. The positive effect on the distal aorta is limited to the thoracic segments but not in the visceral aorta.

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

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

Hemodynamic predictors of negative false lumen remodeling after frozen elephant trunk for acute aortic dissection

OBJECTIVE

We evaluated the blood flow within the downstream aortic false lumen after frozen elephant trunk repair for acute aortic dissection and identified hemodynamic predictors of false lumen expansion and negative false lumen remodeling using four-dimensional flow magnetic resonance imaging.

METHODS

Thirty-one patients (Stanford type A, n = 28; Stanford type B, n = 3) with patent false lumen who underwent frozen elephant trunk procedures for acute aortic dissection were included in this observational study. Each patient underwent computed tomography during the follow-up period and four-dimensional flow magnetic resonance imaging within 3 postoperative months. The false lumen volumetric expansion rate was calculated using computed tomography data. The direction and the rate of flow in the lower descending aortic false lumen were analyzed. Negative false lumen remodeling was defined as a volumetric increase of > 10% from the baseline volume.

RESULTS

Negative false lumen remodeling had developed in 6 of the 31 patients during the observation period. Most of the false lumen flows were biphasic during systole. The range between peak and nadir flow rates was associated with the false lumen volumetric expansion rate (β coefficient = 6.77; p < 0.01, R2 = 0.43).

CONCLUSIONS

The range between peak and nadir flow rates may serve as a hemodynamic predictor of negative false lumen remodeling, enabling further treatment for patients at risk of expansion in the downstream aorta.

The frozen elephant trunk: seeking a more definitive treatment for acute type A aortic dissection

OBJECTIVES

Conventional treatment for type A aortic dissection includes replacement of the ascending aorta with an open distal anastomosis in the hemiarch position. The frozen elephant trunk (FET) is a hybrid technique that extends the repair to the descending thoracic aorta. The goal is to improve resolution of malperfusion syndrome and to induce positive aortic remodelling and reduce the need for reintervention on the downstream aorta. We aim to summarize the data on the short and long-term outcomes of this technique.

METHODS

A thorough search of the literature was conducted isolating all articles dealing with aortic remodelling after the use of FET in case of type A acute aortic dissection. Keywords 'aortic dissection', 'frozen elephant trunk', 'aortic remodelling' and 'false lumen thrombosis' were used. Data for type B and chronic aortic dissections were excluded.

RESULTS

FET use favourably influences aortic remodelling. The main advantages lie in the exclusion of distal entry tears in either the aortic arch or descending aorta thus restoring antegrade blood flow in the true lumen and inducing false lumen thrombosis. False lumen thrombosis is not only induced at the level of the stent deployment but also lower in the distal descending aorta. Moreover, it offers an adequate landing zone in the mid-descending aorta for second-stage endovascular or open surgical aortic repair, if needed.

CONCLUSIONS

FET can be advantageous in the treatment of acute type A aortic dissection dealing with extended aortic pathology.

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.

Thoraflex Hybrid Prosthesis (THP): the profile

INTRODUCTION

With the incidence of thoracic aortic disease on the rise, total arch replacement (TAR) with frozen elephant trunk (FET) remains the gold-standard management strategy due to optimal results. Several FET devices exist commercially on the global market. However, the mainstay and most commonly used and reported device is the Thoraflex Hybrid Prosthesis (THP), with several recent reports suggesting its superiority.

AREAS COVERED

This review aims to collate and summarize the evidence in the literature on the clinical outcomes of TAR with FET using THP, with a focus on mortality, neurological complications, endoleak, distal stent-induced new entry (dSINE), aortic remodeling, coagulopathy, and graft kinking. In addition, the design features of THP is discussed, and an overview of market competitors is also highlighted.

EXPERT OPINION

THP consistently demonstrates its effectiveness in treating complex thoracic aortic pathology through favorable clinical outcomes, which can be attributed to its unique and innovative design. Rates of early mortality ranged 0.6-14.2%, neurological complications 0-25%, endoleak 0-8.4% and dSINE 0-14.5%, with minimal incidence of graft kinking and coagulopathy. Aortic remodeling is favorable and comparable to competitors. All this evidence solidifies THP as the leading FET device, particularly when combined with appropriate patient selection and surgical planning.

The Fate of Conventional Elephant Trunk in the Frozen Elephant Trunk Era

Conventional elephant trunk (cET) and frozen elephant trunk (FET) are two distinct approaches to the surgical treatment of thoracic aortic aneurysms and dissections. With the advent and growing uptake of endovascular technologies, FET is becoming increasingly popular for its potential to be performed as a single-stage operation with better aortic remodeling and less risk of graft kinking than the traditional two-stage cET procedure. However, FET has been associated with a higher risk of spinal cord ischemia and its use in patients with connective tissue disorder remains controversial. The current review aimed to reflect on recent evidence surrounding the application of cET and FET to different types of aortic pathology in both acute and elective settings. Another scope of this review was to compare the characteristics of the currently available FET commercial devices on the global market. Our findings highlight that when the pathology is confined to the proximal descending aorta, such as in Dsine, intervention is often single-staged and false lumen (FL) thrombosis is achieved with good effect. FET remains limited by spinal cord injury and applicability in patients with connective tissue disorder, although some groups have started to circumvent associated complications, likely due to growing surgical expertise. Many other aortic diseases do require second-stage intervention, and even in these cases, there appears to be lower in-hospital mortality when using FET over cET. This is possibly due to the higher rate of endovascular completion facilitated by the completed landing zones created during FET. FET is trending toward becoming the universal treatment modality for extending repair to the descending aorta.

Distal Stent Graft-Induced New Entry After Frozen Elephant Trunk Procedure for Aortic Dissection

BACKGROUND

The purpose of this study was to evaluate the risk factors of distal stent graft-induced new entry (dSINE) after frozen elephant trunk (FET) procedure for aortic dissection (AD) and to consider strategies to prevent this complication.

METHODS

This retrospective review included 52 patients who had undergone aortic arch repair for AD with the FET procedure using J Graft FROZENIX from 2014 to 2020 at a single center. Baseline characteristics, aortic characteristics and mid-term outcomes were compared between patients with and without dSINE. The extent of unfolding of the device and movement of the distal edge of the device were analyzed by multidetector computed tomography. The primary endpoints were survival and freedom from reintervention.

RESULTS

dSINE was the most prevalent complication after FET procedure, with an incidence of 23%. Eleven of 12 patients with dSINE underwent secondary interventions. dSINE was common in chronic aortic dissection (P = 0.001) and was associated with the residual false lumen area (P < 0.001) and movement distance of the distal edge of the device in the cranial direction (P < 0.001).

CONCLUSIONS

The distal edge of the FET is more likely to move in the cranial direction, and this movement may cause dSINE.

Comparison of Short and Midterm Aortic Reinterventions in Acute Type A Aortic Dissection Treated by Frozen Elephant Trunk or Conventional Arch Repair

BACKGROUND

Long-term outcomes after acute type A aortic dissection (ATAAD) are related to remodelling of the descending thoracic aorta and aortic reinterventions. We compared the impact of an extensive repair at the index procedure using the Frozen Elephant Trunk (FET) technique, versus a conventional arch repair, on long-term remodelling of the descending thoracic and reintervention related to the aorta.

METHODS

Consecutive patients who underwent conventional arch repair (conventional group) or FET repair (FET group) for an ATAAD from September 2018 to November 2021 were included. Patients who died before discharge or were lost to follow-up prior to the first appointment were excluded from the analysis. Preoperative and postoperative computed tomography angiography was reconstructed and diameter of the true/false lumen of the remaining aorta was compared up to 1 year. Negative (increased total diameter ≥ 5 mm) aortic remodelling was collected for each computed tomography angiography, as well as aortic reinterventions. Comparison of demographic, anatomical, and perioperative complications data were performed using Wilcoxon test for continuous variables or Chi-square test for categorical covariates. The Kaplan-Meier method estimator was used to assess survival rates. The Log rank test was used to compare survival curves between the 2 groups.

RESULTS

Thirty nine patients were included, 22 in the conventional group and 17 in the FET group (82% males, mean age 60 ± 12 years). In the FET group, distal anastomosis was performed in zone 0 or 1 for 82% of patients using the simplified delivery technique. Median maximum preoperative descending aortic diameter was larger in the FET group (33 mm [30; 37] vs. 30 mm [28; 32] [P = 0.0172]). At 30 days, the rate of negative remodelling on the descending thoracic aorta was significantly higher in the conventional group (50%) than in the FET group (8%, P = 0.02). At 1 year, Kaplan-Meier analysis shown a freedom from descending aortic negative remodeling of 35.1% (95% confidence interval (CI) 18.7-66.1%) in conventional group and 44.9% (CI 95% 26.1-77.2%) in FET group with no significant difference. However, early negative remodelling was observed for the conventional group. Within a year, freedom from reintervention was observed for 74.4% (95% CI 57.1-97%) of patients in the conventional group and 75.5 (95% CI 57.1-99.7%) of patients in the FET group with no significant difference.

CONCLUSIONS

Negative evolution of descending aorta remains a challenge after ATAAD. An extensive repair using the FET technique during the index procedure seems to be associated with satisfying short-term remodelling of descending aorta.

Aortic shape variation after frozen elephant trunk procedure predicts aortic events: Principal component analysis study

Objective

The frozen elephant trunk procedure is a well-established technique for the repair of type A ascending aortic dissection and complex aortic arch pathology. The ultimate shape created by the repair may have consequences in long-term complications. The purpose of this study was to apply a machine learning technique to comprehensively describe 3-dimensional aortic shape variations after the frozen elephant trunk procedure and associate these variations with aortic events.

Methods

Computed tomography angiography acquired before discharge of patients (n = 93) who underwent the frozen elephant trunk procedure for type A ascending aortic dissection or ascending aortic arch aneurysm was preprocessed to yield patient-specific aortic models and centerlines. Aortic centerlines were subjected to principal component analysis to describe principal components and aortic shape modulators. Patient-specific shape scores were correlated with outcomes defined by composite aortic event, including aortic rupture, aortic root dissection or pseudoaneurysm, new type B dissection, new thoracic or thoracoabdominal pathologies, residual descending aortic dissection with residual false lumen flow, or thoracic endovascular aortic repair complications.

Results

The first 3 principal components accounted for 36.4%, 26.4%, and 11.6% of aortic shape variance, respectively, and cumulatively for 74.5% of the total shape variation in all patients. The first principal component described variation in arch height-to-length ratio, the second principal component described angle at the isthmus, and the third principal component described variation in anterior-to-posterior arch tilt. Twenty-one aortic events (22.6%) were encountered. The degree of aortic angle at the isthmus described by the second principal component was associated with aortic events in logistic regression (hazard ratio, 0.98; 95% confidence interval, 0.97-0.99; P = .046).

Conclusions

The second principal component, describing angulation at the region of the aortic isthmus, was associated with adverse aortic events. Observed shape variation should be evaluated in the context of aortic biomechanical properties and flow hemodynamics.

Current knowledge and contemporary management of non-A non-B aortic dissections

Non-A non-B aortic dissection (AAD) is an infrequently documented condition, comprising of only a small proportion of all AADs. The unique anatomy of the aortic arch and the failure of the existing classifications to adequately define individuals with non-A non-B AAD, have led to an ongoing controversy around the topic. It seems that the clinical progression of acute non-A non-B AAD diverges from the typical type A and B dissections, frequently leading to serious complications and thus mandating early intervention. Currently, the available treatment methods in the surgical armamentarium are conventional open, endovascular techniques and combined hybrid methods. The optimum approach is tailored in every individual case and may be determined by the dissection’s location, extent, the aortic diameter, the associated complications and the patient’s status. The management of non-A non-B dissections still remains challenging and a unanimous consensus defining the gold standard treatment has yet to be reached. In an attempt to provide further insight into this perplexing entity, we performed a minireview of the literature, aiming to elucidate the epidemiology, clinical course and the optimal treatment modality.

Intervention rates and outcomes in medically managed uncomplicated descending thoracic aortic dissections

OBJECTIVE

To evaluate the long-term incidence and outcome of aortic interventions for medically managed uncomplicated thoracic aortic dissections.

METHODS

Between January 2012 and December 2018, 91 patients were discharged home with an uncomplicated, medically treated aortic dissection (involving the descending aorta with or without aortic arch involvement, no ascending involvement). After a median period of 4 (first quartile: 2, third quartile: 11) months, 30 patients (33%) required an aortic intervention. Patient characteristics, radiographic, treatment, and follow-up data were compared for patients with and without aortic interventions. A competing risk regression model was analyzed to identify independent predictors of aortic intervention and to predict the risk for intervention.

RESULTS

Patients who underwent aortic interventions had significantly larger thoracic (P = .041) and abdominal (P = .015) aortic diameters, the dissection was significantly longer (P = .035), there were more communications between both lumina (P = .040), and the first communication was significantly closer to the left subclavian artery (P = .049). A descending thoracic aortic diameter exceeding 45 mm was predictive for an aortic intervention (P = .001; subdistribution hazard ratio: 3.51). The risk for aortic intervention was 27% ± 10% and 36% ± 11% after 1 and 3 years, respectively. Fourteen patients (47%) underwent thoracic endovascular aortic repair, 11 patients (37%) thoracic endovascular aortic repair and left carotid to subclavian bypass, 3 patients (10%) total arch replacement with the frozen elephant trunk technique, and 2 patients (7%) thoracoabdominal aortic replacement. We observed no in-hospital mortality.

CONCLUSIONS

The need for secondary aortic interventions in patients with initially medically managed, uncomplicated descending aortic dissections is substantial. The full spectrum of aortic treatment options (endovascular, hybrid, conventional open surgical) is required in these patients.

How to Treat Type B Aortic Dissections in the Presence of an Aberrant Right Subclavian Artery: A Systematic Review

An aberrant right subclavian artery (ARSA) is the most common congenital variant of the aortic arch. Usually, this variation is largely asymptomatic, but sometimes it may be involved in aortic dissection (AD). Surgical management of this condition is challenging. The therapeutic options have been enriched in recent decades by establishing individualized endovascular or hybrid procedures. Whether these less invasive approaches bear advantages, and how they have changed the treatment of this rare pathology, is still unclear. Therefore, we conducted a systematic review. We performed a review of literature from the past 20 years (from January 2000 until February 2021) complying with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. All reported patients treated for Type B AD in the presence of an ARSA were identified and classified into three groups according to the received therapy (open, hybrid, and total endovascular). Patient characteristics, as well as in-hospital mortality, and major and minor complications were determined and statistically analyzed. We identified 32 relevant publications comprising 85 patients. Open arch repair has been offered to younger patients, but significantly less often in symptomatic patients needing urgent repair. Therefore, the maximum aortic diameter was also significantly larger in the open repair group compared with that in the hybrid or total endovascular repair group. Regarding the endpoints, we did not find significant differences. The literature review revealed that open surgical therapies are preferred in patients presenting with chronic dissections and larger aortic diameters, most likely because they are unsuitable for endovascular aortic repair. Hybrid and total endovascular approaches are more often applied in emergency situations, where aortic diameters remain smaller. All therapies demonstrated good, early, and midterm outcomes. But, these therapies carry potential risks in the long term. Therefore, long-term follow-up data are urgently needed to validate that these therapies are sustainable.

Automatic segmentation of thrombosed aortic dissection in post-operative CT-angiography images

PURPOSE

The thrombus in the false lumen (FL) of aortic dissection (AD) patients is a meaningful indicator to determine aortic remodeling but difficult to measure in clinic. In this study, a novel segmentation strategy based on deep learning was proposed to automatically extract the thrombus in the FL in post-operative computed tomography angiography (CTA) images of AD patients, which provided an efficient and convenient segmentation method with high accuracy.

METHODS

A two-step segmentation strategy was proposed. Each step contained a convolutional neural network (CNN) to segment the aorta and the thrombus, respectively. In the first step, a CNN was used to obtain the binary segmentation mask of the whole aorta. In the second step, another CNN was introduced to segment the thrombus. The results of the first step were used as additional input to the second step to highlight the aorta in the complex background. Moreover, skip connection attention refinement (SAR) modules were designed and added in the second step to improve the segmentation accuracy of the thrombus details by efficiently using the low-level features.

RESULTS

The proposed method provided accurate thrombus segmentation results (0.903 ± 0.062 in dice score, 0.828 ± 0.092 in Jaccard index, and 2.209 ± 2.945 in 95% Hausdorff distance), which showed improvement compared to the methods without prior information (0.846 ± 0.085 in dice score) and the method without SAR (0.899 ± 0.060 in dice score). Moreover, the proposed method achieved 0.967 ± 0.029 and 0.948 ± 0.041 in dice score of true lumen (TL) and patent FL (PFL) segmentation, respectively, indicating the excellence of the proposed method in the segmentation task of the overall aorta.

CONCLUSIONS

A novel CNN-based segmentation framework was proposed to automatically obtain thrombus segmentation for thrombosed AD in post-operative CTA images, which provided a useful tool for further application of thrombus-related indicators in clinical and research application.

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.

When endoleak occur after TAR using the fenestrated frozen elephant trunk technique in patients with rare anatomical subtypes, collaboration with other experts facilitates additional treatment.

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.

Volume Changes in the Descending Aorta after Frozen Elephant Trunk and Conventional Hemi-Arch Repair after Acute Type A Aortic Dissection

The aim of this study was to compare the mortality rates, re-intervention rates, and volumetric changes in aortas following surgery, in terms of the true lumen and false lumen changes, using conventional hemi-arch repair (CET) and frozen elephant trunk (FET) techniques. During the period from 2015 to 2018, 66 patients underwent surgical treatment for acute aortic dissection (Debakey type 1). Demographic and procedure-related data were evaluated. We measured volumetric change before surgical treatment, at discharge, and at 12- and 24-month time points based on computed tomography angiography. The study cohort was divided into two groups (FET vs. CET). The mean age of the patients was 56.9 ± 9.4 years in the FET group versus 63.6 ± 11 years in the CET group (p = 0.063). The mean follow-up time was 24 ± 6 and 25 ± 5 months for the FET and CET groups, respectively. There were no significant differences between the two groups in terms of the medical histories of the cohorts. The results showed a significant increase in true lumen volume after the FET procedure (within 24 months postoperatively; p = 0.005), and no significant changes in total (p = 0.392) or false lumen (p = 0.659) volumes were noted. After the CET procedure, there were significant increases in total and false lumen volumes (p = 0.013, p = 0.042), while no significant change in true lumen was observed (p = 0.219). The volume increase in true lumen after the FET procedure was higher compared to the CET group at all postoperative time points (at discharge, 12 months, and 24 months) without significant evidence (p = 0.416, p = 0.422, p = 0.268). At two years, the volume increase in false lumen was significantly higher among the CET group compared to the FET group (p = 0.02). The Kaplan–Meier curve analysis showed that patients who underwent the CET procedure underwent significantly more re-interventions due to false lumen expansion of the descending aorta (p = 0.047). Present study results indicate that the true and false lumen changes in the aorta following the FET and CET procedures were different. FET led to a significant increase in true lumen volume, while false lumen volume remained stable; however, after the CET procedure, significant false lumen enlargement was noted at mid-term follow-up time points. The re-intervention rate after CET was higher due to false lumen expansion.

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.

Aortic remodeling in aortic dissection after frozen elephant trunk: overcoming the challenges

The introduction of the single-step hybrid frozen elephant trunk (FET) procedure expanded the surgeon's armamentarium in managing aortic dissection (AD). This is evident by the reduction in mortality and complication rates associated with conventional techniques used to repair ADs. Although FET still carries a risk of certain complications, it has been associated with excellent aortic remodeling following the procedure. The main scope of this review is to evaluate aortic remodeling in aortic dissection after FET as well as to highlight the challenges that may arise and ways to overcome them. A comprehensive literature search was conducted on multiple electronic databases including PubMed, Ovid, Scopus and Embase to highlight the evidence in the literature on aortic remodeling in aortic dissection after FET. The FET procedure promotes excellent long-term remodeling, this is seen in the substantial increase in the size of the true lumen along with the decrease in that of the false lumen (FL), in addition to significant FL thrombosis. However, this occurs to a lesser extent more distally at the level of the abdominal aorta. Negative remodeling may present a major challenge to the process of aortic remodeling, nevertheless, this can be overcome with endovascular reintervention which has demonstrated highly favorable results. Additionally, the choice of FET graft, in terms of type and length, seems to influence outcomes. Namely, the Thoraflex™ Hybrid graft can be considered the superior graft on the global market. On the other hand, there seems to be a debate in the literature on the optimal FET graft length. The FET procedure has revolutionized the field of aortovascular surgery and promotes excellent long-term aortic remodeling. Negative remodeling can occur but can also be favorably overcome with endovascular reintervention. Finally, the choice of FET graft may also influence results, thus, should be taken with great care.

Aortic remodeling, reintervention, and survival after zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection: Midterm results

Objectives

To investigate the midterm results after zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection.

Methods

Between October 2014 and April 2021, 196 patients underwent zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection. The true lumen area, aortic lumen area, and false lumen status were assessed at four aortic levels, the proximal and distal descending thoracic aorta (level A and level B, respectively), celiac artery branching (level C), and terminal aorta (level D). Aortic remodeling (postoperative area as a percentage of the preoperative area) was classified into 3 groups, positive (true lumen area ≥120% with aortic lumen <120% or true lumen area ≥80% with aortic lumen <80%), minimal (80% ≤ true lumen area and aortic lumen area <120%), and negative remodeling (all other changes).

Results

In-hospital mortality was 13 (6.6%) patients. The overall survival rate was 85.1% at 5 years. The freedom from distal aortic reintervention was 89.9% at 5 years. The prevalence of completely thrombosed or obliterated false lumen at 2 years was 96.8% at level A, 88.4% at level B, 47.2% at level C, and 27.6% at level D. The prevalence of positive aortic remodeling at 2 years was 84.7% at level A, 75.0% at level B, 29.2% at level C, and 16.7% at level D.

Conclusions

Zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection can avoid invasive aortic arch resection and facilitate aortic remodeling of the descending thoracic aorta. The FET effect on aortic remodeling is limited at the aortic level below the FET stent end.

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.

Volumetric Measurements Improve the Accuracy of Aortic Remodeling Prediction in Aortic Dissection

Accessing aortic remodeling status through regular follow-ups is essential for acute type A aortic dissection patients undergone surgical treatment. Aortic remodeling status was usually determined using diameter or area measurements of the true and false lumen in specific anatomical slices of medical images. However, these indicators only represent partial information about the aorta and can hardly characterize the overall aorta situation. In this study, we included two types of morphology features collected from computed tomography angiography images to predict the aortic remodeling. One type is the volumetric measurements of the true and false lumen, which provide a better overall description of the aorta, and the other type is the volumetric measurements of the thrombus in false lumen and the patent false lumen, which present more detailed information of the dissection. Through progressively incorporating these measurements into the construction of the remodeling prediction model, we investigated the importance of the features that describe the overall situation and that characterize aortic internal details in remodeling prediction, especially the effect of quantitative thrombosis features. The results showed that with the inclusion of the two types of volume features, the prediction accuracy of the model increased, which proves that volumetric measurements of aortic dissection, especially the volume of thrombus, are of significant value in aortic remodeling prediction, and should be paid more attention on in clinical practice and research areas. Clinical Relevance-Demonstrating the importance of volumetric measurements of true and false lumen thrombus in false lumen and patent false lumen in the prediction of aortic remodeling.

Distal Aortic Failure Following the Frozen Elephant Trunk Procedure for Aortic Dissection

Background

Aim of this study was to report and to identify risk factors for distal aortic failure following aortic arch replacement via the frozen elephant trunk (FET) procedure.

Methods

One hundred eighty-six consecutive patients underwent the FET procedure for acute and chronic aortic dissection. Our cohort was divided into patients with and without distal aortic failure. Distal aortic failure was defined as: (I) distal aortic reintervention, (II) aortic diameter dilatation to ≥ 6 cm or > 5 mm growth within 6 months, (III) development of a distal stent-graft-induced new entry (dSINE) and/or (IV) aortic-related death. Preoperative, intraoperative, postoperative and aortic morphological data were analyzed.

Results

Distal aortic failure occurred in 88 (47.3%) patients. Forty-six (24.7%) required a distal reintervention, aortic diameter dilatation was observed in 9 (4.8%) patients, a dSINE occurred in 22 (11.8%) patients and 11 (6.4%) suffered an aortic-related death. We found no difference in the number of communications between true and false lumen (p = 0.25) but there were significantly more communications between Ishimaru zone 6–8 in the distal aortic failure group (p = 0.01). The volume of the thoracic descending aorta measured preoperatively and postoperatively within 36 months afterward was significantly larger in patients suffering distal aortic failure (p < 0.001; p = 0.011). Acute aortic dissection (SHR 2.111; p = 0.007), preoperative maximum descending aortic diameter (SHR 1.029; p = 0.018) and preoperative maximum aortic diameter at the level of the diaphragm (SHR 1.041; p = 0.012) were identified as risk factors for distal aortic failure.

Conclusion

The incidence and risk of distal aortic failure following the FET procedure is high. Especially those patients with more acute and more extensive aortic dissections or larger preoperative descending aortic diameters carry a substantially higher risk of developing distal aortic failure. The prospective of the FET technique as a single-step treatment for aortic dissection seems low and follow-up in dedicated aortic centers is therefore paramount.

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.

Normothermic frozen elephant trunk: our experience and literature review

BACKGROUND AND OBJECTIVE

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

METHODS

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

KEY CONTENT AND FINDINGS

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

CONCLUSIONS

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

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

Objective

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

Methods

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

Results

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

Conclusions

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

“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.

NEO E-vita—NEO era!

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

A New Era of Diagnosis and Therapy in Acute Aortic Syndromes: The Mainz-Essen Experience (Part II)-Management and Outcomes

Over the years, the cardiovascular department of Johannes Gutenberg University in Mainz-West-German Heart Centre in Essen (Germany) designed and implemented the hybrid operating room (2003) along with advanced endovascular and surgical procedures, including the frozen elephant trunk technique. For the study purpose, the Mainz-Essen experience on acute aortic syndromes was summarized by considering original articles from single-center or multicenter studies performed at West German Heart Centre, Essen, Germany, or at the cardiovascular department of Johannes Gutenberg University, Mainz, Germany. We present the 35-year-long Mainz-Essen research, education, and patient management journey in creating an integrated multidisciplinary "Aortic Center" in the heart of Europe.

False lumen thrombosis after frozen elephant trunk procedure in acute and chronic aortic dissection

BACKGROUND

The clinical significance of the false lumen (FL) thrombosis after the thoracic aortic surgery consists in the correlation with aortic remodeling. The aim of the study was to analyze the incidence of the FL thrombosis of the thoracoabdominal aorta after the frozen elephant trunk (FET) procedure in acute and chronic aortic dissection.

METHODS

A total of 57 consecutive patients with type A and B aortic dissection (AD) underwent the FET procedure between March 2012 and December 2020 were included in a retrospective study. All of the patients were divided in two groups: acute (n=18) and chronic (n=39) AD. Early and 2-year outcomes were evaluated in both groups. Computed tomography scans were obtained along the entire aorta for the aortic status assessment.

RESULTS

There were no statistically significant differences in early mortality and postoperative outcomes in both groups. The 2-year survival rate in acute and chronic AD was 74.7%±10% vs. 71.4%±7% (p=0.573), respectively. In the follow-up, the FL thrombosis rate, changes of the true lumen and total aortic diameters did not differ significantly between the analyzed groups of patients. The freedom from negative aortic remodeling was 62.2%±26% in acute AD versus 76.2%±11% in chronic AD (p=0.853). One (5.6%) and 4 (10.3%) distal aortic re-interventions were performed in acute and chronic AD, respectively.

CONCLUSIONS

False lumen thrombosis rate after the FET procedure did not differ significantly in acute and chronic AD.

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.

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

 

OBJECTIVES

To improve organ protection with the frozen elephant trunk (FET) procedure, a so-called four-sites perfusion in combination with proximalization for the distal aortic anastomosis was performed. The impact of these techniques on patient outcome is reported.

METHODS

Between February 2005 and April 2020, a total of 357 patients underwent the FET procedure for acute (54%) or chronic (22%) aortic dissection or aneurysmal disease (24%). The level of the distal FET anastomosis was defined according to aortic arch zones 0–3. Patients were divided into 3 groups according to the intraoperative perfusion strategy: (i) selective antegrade cerebral perfusion (SACP) alone (N = 96, 2 sites); (ii) SACP plus left subclavian artery or distal aorta (N = 84, 3 sites) and (iii) SACP plus left subclavian artery plus distal aorta (N = 177, 4 sites). Early outcome was addressed by a composite end point: occurrence of either a disabling stroke, a disabling spinal cord injury, extracorporeal circulatory support, kidney dialysis or death within 90 days.

RESULTS

Preoperative characteristics were similar among the groups. Surgery in group C was characterized by FET proximalization in arch zone ≤2, moderate hypothermia at 28°C and shorter periods of extracorporeal circulation, SACP, hypothermic circulatory arrest and cardioplegic arrest (P < 0.001, respectively). Occurrence of the composite end point was reduced in group C (P = 0.008). The combination of FET proximalization and four-sites perfusion was a protective factor for the composite outcome in multivariable analysis (P = 0.009). The 5-year survival was improved in patients who underwent FET proximalization in zone ≤2 (hazard ratio 0.7, 95% confidence interval 0.4–1.0; P = 0.036).

CONCLUSIONS

FET proximalization in combination with four-sites perfusion has the potential to improve patient outcomes in terms of survival and major events.

Subject collection

120; 161.

Distal Aortic Remodeling after Type A Dissection Repair: An Ongoing Mirage

Remodeling is a commonly encountered term in the field of cardiothoracic surgery that is often used to describe various pathophysiological changes in the dimension, structure, and function of various cardiac chambers, including the aorta. Stanford type A or DeBakey type 1 aortic dissection (TAAD) is a perplexing pathologic condition that can present surgical teams with the need to navigate a maze of complex decision-making. Ascending or hemi-arch replacement leaves behind a significant amount of distal diseased aortic tissue, which might have a persistent false lumen or primary or secondary intimal tears (or communications between lumina), which can lead to dilatation of the aortic arch. Unfavorable aortic remodeling is a major cause of distal aortic deterioration after the index surgery. Cardiac surgeons are aware of post-surgical cardiac chamber remodeling, but the concept of distal aortic remodeling is still idealized. The contemporary literature from established aortic centers supports aggressive management of the residual aortic pathology during the index surgery, and with continuing technical advancements, endovascular stenting options are readily available for patients with TAAD or for complicated type B aortic dissection cases. This review discusses the pathophysiology and treatment options for favorable distal aortic remodeling, as well as its impact on mid- to long-term outcomes following TAAD repair.

Changes of stent-graft orientation after frozen elephant trunk treatment in aortic dissection

OBJECTIVES

Our goal was to evaluate the extent of stent-graft (SG) elastic recoil in the descending aorta after the frozen elephant trunk procedure in acute (AAD) and chronic (CAD) aortic dissection as well as the impact of SG movement on distal stent graft-induced new entry (d-SINE).

METHODS

We retrospectively analysed 149 (105 AAD, 44 CAD) of 259 aortic dissection patients after the frozen elephant trunk procedure between January 2005 and April 2019. Inclusion criteria were at least 1-year computed tomography angiography (CTA) aortic examinations during a follow-up time of 3.8 ± 2.7 years and absence of open or endovascular reintervention. Multiplanar reconstruction of CTA scans was used to define the SG vector position and movement in a virtual Cartesian coordinate system. The angle φ of vector movement and changes of aortic areas at the distal landing zone were analysed.

RESULTS

The distal SG position changed over time in the cranial (10.06 ± 11.12 mm), dorsal (8.45 ± 11.12 mm) and lateral (4.96 ± 9.89 mm) directions (P < 0.001). The total change of φ (4.08 ± 7.03°) was greater in AAD than in CAD (P = 0.026). d-SINE was more common in CAD (P < 0.001) and was associated with the size of the aortic area, aortic area enlargement and continuous SG unfolding (P < 0.001).

CONCLUSIONS

With the frozen elephant trunk technique, movement and change of SG orientation in the descending aorta were observed over time. Elastic recoil was greater in AAD than in CAD. The incidence of d-SINE was particularly dependent on the size of the aortic lumen and SG radial expansion and less on elastic recoil.

Short- and mid-term outcomes of the frozen elephant-trunk procedure for degenerative aortic arch aneurysm

PURPOSE

The frozen elephant-trunk (FET) procedure is used widely in total aortic arch replacement (TAR) surgery; however, its safety, effectiveness, and long-term outcomes compared with those of the conventional elephant trunk (cET) procedure for degenerative aneurysms are unclear.

METHODS

Between July, 2011 and August, 2019, 126 patients underwent elective total aortic arch replacement at our institution. We compared the short- and mid-term outcomes of 60 patients who underwent the FET procedure (FET group) with those of 66 patients who underwent cET (cET group).

RESULTS

The in-hospital mortality rate tended to be lower in the FET group than in the cET group (p = 0.12). There were two cases of paraplegia (3.3%) in the FET group and in none in the cET group. The all-cause mortality at the 3-year follow-up did not differ significantly between the groups (p = 0.31). The FET group required more unexpected interventions at the surgical site in the mid-term period.

CONCLUSIONS

FET was associated with a shorter operative time and lower surgical mortality than cET. Although the mid-term total aortic arch replacement outcomes of FET were acceptable, careful imaging observation is necessary because reinterventions were required more frequently.

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

OBJECTIVES

We investigated the outcomes of a fenestrated frozen elephant trunk (FET) technique performed without reconstruction of one or more supra-aortic vessels for aortic repair in patients with acute type A aortic dissection.

METHODS

We investigated 22 patients who underwent the fenestrated FET technique for acute type A aortic dissection at our hospital between December 2017 and April 2020. The most common symptom was chest pain and/or back pain. Nine patients presented with malperfusion and 1 with cardiac arrest, preoperatively. A FET was deployed under hypothermic circulatory arrest and manually fenestrated under direct vision. Single fenestration was made in the FET in 15 patients, 2 fenestrations in 5 patients and a total fenestrated technique in 2 patients. Concomitant procedures were performed in 5 patients.

RESULTS

The cardiopulmonary bypass, aortic cross-clamp and hypothermic circulatory arrest times were 181 ± 49, 106 ± 43 and 37 ± 7 min, respectively. In-hospital mortality, stroke, or recurrent nerve injury did not occur in any patient. One patient developed paraparesis, which completely recovered at discharge. During the follow-up period (mean 18 ± 7 months), 1 patient died of heart failure. Fenestration site occlusion did not occur. Follow-up computed tomography (mean 12 ± 6 months postoperatively) revealed that the maximal aortic diameter remained unchanged at the levels of the distal end of the FET, the 10th thoracic vertebra and the coeliac artery; however, the aortic diameter was significantly reduced at the level of the pulmonary artery bifurcation.

CONCLUSIONS

The fenestrated FET technique is a simple, safe and effective procedure for selected patients with acute type A aortic dissection.

Outcomes of long versus short stent cronus hybrid prosthesis in type A aortic dissection: A single centre experience

OBJECTIVES

The frozen elephant trunk (FET) technique has become an important tool in the treatment of acute type A aortic dissection. The aim of this study was to evaluate the effect of long FET on spinal cord injury (SCI) and distal aortic remodeling after acute type A aortic dissection based on clinical and radiological outcomes.

METHODS

From January 2018 to November 2019, 158 patients (mean age 51.8 years [range: 32-78 years], 88.6% male) with acute type A aortic dissection were treated by FET with 100 mm (n = 113) or 150 mm (n = 45) open hybrid stent graft prosthesis. Patients were divided into two groups according to the length of FET. The clinical and radiological outcomes of the patients were reviewed retrospectively.

RESULTS

Postoperative outcomes did not differ significantly: in-hospital mortality (9.7% vs. 6.7%, p = .758) and SCI (5.3% vs. 2.2%, p = .674). Aortic remodeling, which was evaluated by aortic diameter, true lumen diameter, false lumen (FL) diameter and the rate of FL complete thrombosis, was more positive in long FET group in the descending thoracic aorta during the follow-up period. At the abdominal level, there was no statistically significant difference between the two groups.

CONCLUSIONS

The long version of FET does not increase the risk of SCI in patients with acute type A aortic dissection. The application of long FET can achieve better results in terms of remodeling of the thoracic aorta in the short- and medium-term follow-up.

Aortic proximalization-Zone 0 versus Zone 2: A concept or true challenge?

BACKGROUND

The use of the Frozen Elephant Trunk (FET) device to manage complex surgical pathologies of the aorta (such as acute type A aortic dissection) has gained popularity since its introduction in the early 2000s. Though the distal anastomosis was traditionally performed at aortic Zone 3 (Z-3-FET), preference gradually shifted towards Zone 2 (Z-2-FET) in favor of improved surgical access and clinical outcomes. This review seeks to elucidate whether proximalization of arch repair to Zone 0 (Z-0-FET) would further improve postoperative outcomes.

METHODS

We performed a review of available literature to evaluate the comparative efficacies of Z-2-FET versus Z-0-FET, in terms of surgical technique, clinical outcomes, and incidence of adverse events.

RESULTS

Z-0-FET seems to be associated with a more accessible surgical approach, and shorter cardiopulmonary bypass, antegrade cerebral perfusion, and cardioplegia durations than Z-2-FET. Further, Z-0-FET is could potentially be associated with a lower incidence of neurological, renal, and recurrent laryngeal nerve injury, as well as mortality and reintervention rates than Z-2-FET. This said, Z-0-FET is itself associated with significant challenges, and efficacy in terms of postoperative true lumen integrity and false lumen thrombosis is mixed.

CONCLUSION

Current literature seems to suggest that Z-0-FET procedures are more straightforward and associated with lower rates of certain adverse events, however, the majority of data reviewed is retrospective. This review, therefore, recommends prospective research into the comparative strengths and limitations of Z-0-FET and Z-2-FET to better substantiate whether proximalization of arch repair represents a concept, or a true challenge to advance surgical intervention for arch pathologies.

Non-A non-B aortic dissection: A literature review

Non-A non-B aortic dissections are an infrequent occurrence and represent a small proportion of aortic dissections. Treating this life-threatening medical emergency often requires surgeons to undertake some one of the most challenging surgical or endovascular cases in medicine. This literature review aims to define and classify non-A non-B dissections, describe their epidemiology as well as their pathology. This review also aims to discuss the range of surgical techniques employed in their treatment and management and to investigate the patient outcomes associated with each technique.

Is the classical elephant trunk better than the frozen elephant trunk?

Aortic diseases located in the ascending aorta, aortic arch or proximal descending aorta often require more than one surgical intervention depending on the type of pathology and its extent as well as future anticipated aortic problems. These obstacles were tackled in 1983 by Hans Borst with the introduction of the classic elephant trunk (cET). This was an outstanding and straightforward procedure. Since then, the cET was very often the first surgical approach for patients with extensive aortic pathology of the ascending aorta and arch extending into the downstream aorta. Thirteen years later, Suto and Kato introduced the frozen elephant trunk (fET) which was later on perfectionized by industry and applied in various ways by many surgical groups worldwide. Comparing the cET with the fET raises a lot of difficulties. The lack of randomization and the presence of procedural and complication-related limitations for each technique do not allow for definitive conclusions about the ideal procedure to treat complex aortic pathology. It would be very short-sighted to close all future discussions about the subject with this statement of the Hannover group made in 2011. Since both techniques and its results cannot be compared statistically due to the heterogeneity of patient groups, the lack of randomization, the difference in type and extent of pathology, the differences in surgical techniques, the learning curve in gaining experience in both techniques, and the lack of reporting standards, no scientific conclusion can be drawn as to which technique is most successful. Comparisons may even be considered futile. It is the purpose of this paper merely to make a descriptive observation of both techniques, to discuss some important elements of interest and to give some constructive and useful criticism.

Thoraflex hybrid as frozen elephant trunk in chronic, residual type A and chronic type B aortic dissection

OBJECTIVES

The frozen elephant trunk technique is an increasingly common treatment for extensive disease of the thoracic aorta. The objective of the study was to evaluate the outcomes of frozen elephant trunk specifically in chronic (residual) aortic dissections, focusing on downstream aortic remodelling.

METHODS

Between 2013 and 2019, a total of 28 patients were treated using the Vascutek Thoraflex hybrid graft at our institution for chronic dissections/post-dissection aneurysms. Immediate and follow-up outcomes were studied, as well as the changes in total aortic diameter, true lumen and false lumen diameter and the status of the false lumen at 3 different levels of the thoraco-abdominal aorta.

RESULTS

No in-hospital or 30-day mortality was observed, temporary paraparesis rate was 7% and disabling stroke incidence was 14.3%. Freedom from all-cause mortality at 2 years was 91.6 ± 5.7%, while freedom from reintervention on the downstream aorta at 2 years was 59.1 ± 10.8%. Positive aortic remodelling was achieved in 50.0%, with an enlargement in the true lumen and a reduction of the false lumen not only at the level of the proximal descending aorta with 73.1% of complete thrombosis but also at the level of the distal descending thoracic aorta, with 41.7% of complete thrombosis.

CONCLUSIONS

The frozen elephant trunk is a good solution in chronic (residual) downstream aortic dissections inducing positive aortic remodelling and preventing from II stage operations or allowing an endovascular approach.

The frozen elephant trunk technique for acute retrograde type A aortic dissection: preliminary results

OBJECTIVES

Our goal was to determine the early and midterm outcomes after total arch replacement with the frozen elephant trunk (FET) technique compared to those of the conventional elephant trunk (ET) technique for acute retrograde type A aortic dissection.

METHODS

Between 2012 and 2019, a total of 49 patients had total arch replacement for acute retrograde type A aortic dissection. Patients were divided into the conventional ET (n = 17) and FET (n = 32) groups. The false lumen status was evaluated using enhanced computed tomography (CT) 1 week postoperatively. The diameter of the downstream aorta was evaluated annually using CT. The median follow-up period was 29 months.

RESULTS

Preoperative data and neurological complications were not significantly different in the 2 groups. The diameter and length of the ET prosthesis were significantly larger and longer in the FET group. The overall early mortality rate was 10.2% (5/49) with no differences between the 2 groups. The mean follow-up period was significantly longer in the conventional ET group. The rates of freedom from aortic events at 3 years were significantly lower in the FET group. At the level of the distal arch, postoperative false lumen patency was significantly lower and the follow-up aortic diameter was significantly smaller in the FET group.

CONCLUSIONS

The FET technique facilitates false lumen thrombosis and aortic remodelling at the distal arch level, with fewer adverse aortic events during the follow-up period with acceptable early outcomes; however, these findings are exploratory and require investigation.

The frozen elephant trunk technique in an emergency: THORAFLEX French National Registry offers new insights

OBJECTIVES

Our goal was to study the immediate outcome after an emergency frozen elephant trunk procedure with a Thoraflex™ Hybrid prosthesis (THP) in patients included in the EPI-Flex national registry and operated on in 21 French centres.

METHODS

All patients operated on in France between April 2016 and April 2019 for acute aortic syndromes and who had an frozen elephant trunk procedure with a THP were included in the study. The main end point was in-hospital mortality. The secondary end point was neuromorbidity, including paraplegia. The evolution of the main end point was monitored using a variable life-adjusted display graph with cumulative sum derivatives in order to stop inclusions in case the observed mortality became out of range compared to an expected mortality between 15% and 20%.

RESULTS

Enrolment ended on the scheduled date and included 109 patients. Most cases (54%) were performed at 3 centres, where more than 10 THP each were implanted (10-26). The observed mortality in the large-volume centres (22%) was comparable to that observed in the low-volume centres (20%). The individually risk-adjusted cumulative sum revealed that observed in-hospital mortality was statistically in line with that predicted by the log EuroSCORE. Analysis of the secondary end point revealed 8% cases of paraplegia, all of which appeared after treatment of the thoracic type A aortic dissection.

CONCLUSIONS

In France, THP for emergency frozen elephant trunk surgery outside high-volume centres did not result in excessive in-hospital deaths. However, a word of caution must be expressed regarding the prevention of medullar ischaemia even in emergency aortic surgery.