Aortic diameter remodelling after the frozen elephant trunk technique in aortic dissection: results from an international multicentre registry†

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.

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

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSIONS

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

Next-Generation Frozen Elephant Trunk Technique in the Era of Precision Medicine

The frozen elephant trunk (FET) technique can be applied to extensive aortic pathology, including lesions in the aortic arch and proximal descending thoracic aorta. FET is useful for tear-oriented surgery in dissections, managing malperfusion syndrome, and promoting positive aortic remodeling. Despite these benefits, complications such as distal stent-induced new entry and spinal cord ischemia can pose serious problems with the FET technique. To prevent these complications, careful sizing and planning of the FET are crucial. Additionally, since the FET technique involves total arch replacement, meticulous surgical skills are essential, particularly for young surgeons. In this article, we propose several techniques to simplify surgical procedures, which may lead to better outcomes for patients with extensive aortic pathology. In the era of precision medicine, the next-generation FET device could facilitate the treatment of complex aortic diseases through a patient-tailored approach.

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

OBJECTIVE

To evaluate the 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 Strengthening the Reporting of Observational Studies in Epidemiology (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 remodeling were analyzed.

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 2 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 or retrograde aortic dissection 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 false lumen thrombosis (100% vs 55.5%, P = 0.033), and a significant positive aortic remodeling in zone 3 (P < 0.001) and 4 (P = 0.038) were reported in operated versus medically managed patients.

CONCLUSIONS

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

Aortic diameter remodeling after frozen elephant trunk as a predictor of early outcomes in thoracoabdominal aortic repair

OBJECTIVE

Patients who underwent previous frozen elephant trunk implantation for Stanford type A aortic dissection remain at risk for secondary intervention due to unsuccessful distal aortic remodeling. We aimed to investigate the impact of distal aortic remodeling on early outcomes in patients who underwent 2-stage thoracoabdominal aortic repair.

METHODS

A total of 106 patients who previously underwent frozen elephant trunk implantation and thoracoabdominal aortic repair between October 2014 and December 2022 were enrolled in this study. The extent of distal aortic remodeling was evaluated, including aortic diameter, area ratio of the false lumen/aortic lumen, and patency of the false lumen at 3 levels of the aorta. Logistic regression analyses were performed to investigate the risk factors for early outcomes.

RESULTS

The aortic diameter at the distal frozen elephant trunk was significantly larger in patients who died early than in surviving patients (79.19 ± 22.89 mm vs 46.84 ± 19.17 mm, respectively, adjusted P = .001). The optimal cutoff value for the aortic diameter at the distal frozen elephant trunk was 60 mm. Patients with an aortic diameter 60 mm or more at the distal frozen elephant trunk had worse early outcomes (P < .05), including prolonged intubation, early death, and postoperative complications. The aortic diameter at the distal frozen elephant trunk was identified as a significant risk factor for early death in patients undergoing thoracoabdominal aortic repair.

CONCLUSIONS

Patients undergoing thoracoabdominal aortic repair with an aortic diameter 60 mm or more at the distal frozen elephant trunk have worse early outcomes. Moreover, an aortic diameter at the distal frozen elephant trunk is a significant risk factor for early death in patients undergoing thoracoabdominal aortic repair.

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 requires 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 use in type a dissection: fundamentals, innovations, and pitfalls

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

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.

Complementary Thoracic Endovascular Aortic Repair (TEVAR) after Frozen Elephant Trunk for Residual Type A Aortic Dissection: Perioperative and Mid-Term Outcomes

Objectives: The aim of this retrospective study was to evaluate the results of complementary TEVAR following the frozen elephant trunk (FET) procedure for patients with residual type A aortic dissection (rTAAD) in terms of technical feasibility, safety and mid-term outcomes. Methods: This was a retrospective single-centre analysis of patients who received TEVAR after FET for rTAAD from January 2012 up to December 2021. The primary endpoint was technical success. Safety parameters included 30-day/in-hospital morbidity and mortality. Furthermore, mid-term clinical and morphological outcomes were evaluated. Results: Among 587 TEVAR procedures, 60 patients (11 with connective tissue disorders) who received TEVAR after FET for rTAAD were identified. The median interval between FET and TEVAR was 28.5 months. Indications for TEVAR after FET were true lumen collapse distal to FET prosthesis (n = 7), dSINE (n = 2), planned completion (n = 13) and aortic diameter progression (n = 38). In forty-seven patients, TEVAR was performed in an elective setting; eight and six patients were operated on in an urgent or emergency setting, respectively. All TEVAR procedures were successfully completed. The 30-day mortality and spinal cord ischemia rates were 1.7%. During a median follow-up of 37 months, two further patients died. Nine patients had to undergo a further aortic intervention: fenestrated stent-graft (n = 3) or open repair of the infrarenal abdominal aorta (n = 6). Conclusions: Complementary TEVAR following FET for rTAAD showed excellent technical success and low perioperative risk, supporting the feasibility and safety of this strategy. Despite the favourable mid-term survival, certain patients might require a further aortic procedure.

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.

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

Objective

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

Methods

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

Results

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

Conclusion

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

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.

Hybrid Treatment of Complex Diseases of the Aortic Arch and Descending Thoracic Aorta by Frozen Elephant Trunk Technique

The surgical management of acute and chronic complex diseases involving the aortic arch and the descending thoracic aorta remains challenging. Hybrid procedures associating total open arch replacement and stent-grafting of the proximal descending aorta were developed to allow a potential single-stage treatment, promote remodeling of the downstream aorta, and facilitate a potential second-stage thoracic endovascular aortic repair by providing an ideal landing zone. While these approaches initially used various homemade combinations of available conventional prostheses and stent-grafts, the so-called frozen elephant trunk technique emerged with the development of several custom-made hybrid prostheses. The aim of this study was to review the contemporary outcomes of this technique in the management of complex aortic diseases, with a special focus on procedural planning, organ protection and monitoring, refinements in surgical techniques, and long-term follow-up.

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.

Impact of frozen elephant trunk on the outcomes of thoracoabdominal aortic repair with normothermic iliac perfusion

Background

Frozen elephant trunk technique (FET) has been proven to provide an excellent landing zone for second-stage thoracoabdominal (TA) aortic repair. The aim of this study was to evaluate the impact of FET in TA aortic repair with normothermic iliac perfusion.

Methods

From January 2008 to December 2019, 144 patients undergoing TA repair with normothermic iliac perfusion were enrolled in this study. Early and mid-term outcomes of patients with previous FET implantation (group A, n = 62) were compared with patients without previous FET implantation (group B, n = 82). The logistic regression analysis was performed to investigate the risk factors for adverse events, which were defined as early death, permanent stroke, permanent paraplegia, or permanent renal failure necessitating dialysis.

Results

The proximal aortic clamp time and operating time was 14.26 ± 5.57 min and 357.40 ± 94.51 respectively in group A, which were both significantly shorter than that in group B (18.67 ± 5.24 min and 18.67 ± 5.24 min). The incidence of adverse event was significantly lower in group A than that in group B (9.7% vs. 25.6%, P = 0.027). There was no significant difference between two groups with regard to other complications or late outcomes. In addition, age >50 years, a Ccr < 90 ml/min/1.73 m² and the operating time were identified as significant risk factors through logistic regression analysis for adverse events of TA repair.

Conclusions

The FET technique simplifies the operative technique of proximal anastomosis, decreases the operating time and improves the early outcomes in TA repair, whereas does not provide a significant benefit with regard to late outcomes. Long-term follow-up and studies with larger sample sizes are necessary for further confirmation.

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.

Left Subclavian Artery Sacrifice in Acute Aortic Dissection Repair using the Frozen Elephant Trunk

OBJECTIVE

Surgery of acute aortic dissection using the frozen elephant trunk (FET) can be complicated when the origin of the left subclavian artery (LSA) is dissected and sacrifice by ligation is a viable option. However, the LSA is supposed to play a role in neuroprotection as a major collateral. We, therefore, analyzed our results of LSA sacrifice in this cohort.

METHODS

We identified a total of 84 patients from our prospectively collected database who underwent FET repair of acute aortic dissection between October 2009 and April 2018. LSA was sacrificed in 19 patients (22.6%). Results were analyzed and compared with regard to neurological outcomes.

RESULTS

New postoperative stroke was seen in two patients (2.4%) and spinal cord injury in three patients (3.6%) overall, none in the LSA-sacrifice group. We observed a temporary neurological deficit in five patients (6.0%) overall, none in the LSA-sacrifice group. None of the patients developed acute ischemia of the left arm. Only two patients (12.5%) came back for carotid-subclavian artery bypass due to exertion-induced weakness of the left arm 3 to 4 months after the initial surgery. In-hospital mortality was 15.5% overall, with no difference between groups.

CONCLUSION

LSA sacrifice was not associated with elevated postoperative risk of either central or spinal neurological injury. Thus, it can facilitate FET repair of acute aortic dissection in selected cases when the left subclavian origin cannot be preserved. Carotid-subclavian artery bypass became necessary in only a small fraction of these patients and can be performed as a second-stage procedure.

Sex differences in acute type A aortic dissection: a systematic review and meta-analysis

INTRODUCTION

The objective of this study is to provide a comprehensive comparison of outcomes following acute type A aortic dissection (ATAAD) repair in males and females.

EVIDENCE ACQUISITION

PubMed, Medline, and Web of Science were systematically searched by two authors for studies published from January 1^st, 2000, to May 10^th, 2021. Overall, 2405 articles were screened, and 16 were included in this review. Meta-analysis of the compiled data was performed.

EVIDENCE SYNTHESIS

Pooled estimates indicated no difference in operative (odds ratio (OR) 1.00, 95% confidence interval (CI) 0.59-1.67, P=0.99, I²=52%), in-hospital (OR 0.78, 95% CI 0.56-1.08; P=0.13, I²=57%), and 30-day mortality (OR 1.09, 95% CI 0.83-1.43, P=0.52, I²=45%) between the sexes. However, males had significantly reduced 5-year mortality rates (OR 0.71, 95% CI 0.51-1.00, P=0.05, I²=45%). There was no difference between sexes in rates of postoperative stroke (OR 1.07, 95% CI 0.86-1.33, P=0.54, I²=0%), atrial fibrillation (OR 0.99, 95% CI 0.82-1.19, P=0.92, I²=0%), as well as mesenteric or limb ischemia (OR 0.73, 95% CI 0.22-2.43, P=0.61, I²=77%; OR 0.83, 95% CI 0.30-2.30, P=0.72, I²=76%, respectively). Males did experience significantly increased rates of acute renal failure and reoperation (OR 1.35, 95% CI 1.16-1.56, P=0.0001, I²=29%; OR 1.40, 95% CI 1.09-1.81, P=0.010, I²=42%).

CONCLUSIONS

Composite analysis indicates that early mortality does not differ between the sexes; however, late outcomes favor males. Differences in preoperative presentation and subsequent procedure selection between the sexes likely contribute to the disparity in late outcomes. Decision-making for surgical treatment of ATAAD should account for sex-specific risk factors.

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.

Fenestrated-branched endovascular repair for distal thoraco-abdominal aortic pathology after total aortic arch replacement with frozen elephant trunk

OBJECTIVE

To report the outcomes of fenestrated-branched endovascular repair (FBEVAR) for thoracoabdominal aortic pathology after total aortic arch replacement with frozen elephant trunk (TAR+FET).

METHODS

Interrogation of prospectively-maintained databases from four high volume aortic centres identified consecutive patients treated with distal FBEVAR after prior TAR+FET between August 2013 and September 2020. Primary endpoint was 30-day/in-hospital mortality. Secondary end points were technical success, early clinical success, mid-term survival and freedom from re-intervention. Data are presented as median (IQR).

RESULTS

39 patients [21 men; median age, 73 years (67-75)] with degenerative (n=22) and post-dissection TAAAs (n=17) [median diameter 71 mm (61-78)] were identified. Distal FBEVAR was intended in 27 patients [median interval 9.8 months (6.2-16.6)], anticipated in seven and unexpected in five. 31 patients had a two (n=24) or three (n=7) stage distal FBEVAR. Reno-visceral target vessel preservation was 99.3% (145 of 146). Early primary and secondary technical success was 92% and 97%, respectively. 30-day mortality was 2.6% [n=1; respiratory failure and spinal cord ischaemia (SCI)]. Six survivors also developed SCI which was associated with complete (n=4), or partial recovery (n=2) at hospital discharge. No patients required renal replacement therapy or suffered a stroke. Early clinical success was 95%. Median follow-up was 30.5 months (23.7-49.7). Eleven patients required 16 late re-interventions. Estimated 3-year survival and freedom from re-intervention were 84±6% and 63±10%, respectively.

CONCLUSIONS

Distal FBEVAR after prior TAR+FET is associated with high technical success and low early mortality. The risk of SCI is significant although the majority of patients demonstrate full or partial recovery before hospital discharge. Mid-term patient survival is favourable but there remains a high requirement for late re-intervention. FBEVAR represents an acceptable alternative to distal open TAAA repair.

Incidence of Distal Stent Graft Induced New Entry vs. Aortic Remodeling Associated With Frozen Elephant Trunk

Background

The introduction of the frozen elephant trunk (FET) technique for total arch replacement (TAR) has revolutionized the field of aortivascular surgery by allowing hybrid repair of complex aortic pathologies in a single step through combining an open surgical approach with an endovascular one. FET has been associated with favorable aortic remodeling, however, its is also associated with development of distal stent graft induced new entry (dSINE) tears postoperatively. The rate of aortic remodeling and the incidence of dSINE have been linked together, in addition, there seems to be a relationship between these two variables and FET insetion length as well as graft size.

Aims

The scope of this review is to highlight the rate of aortic remodeling as well the incidence of dSINE associated with different FET devices available commercially. This review also aimed to investigate the relationship between aortic remodeling, dSINE, FET insertion length and FET graft size.

Methods

We conducted a comprehensive literature search using multiple electronic databases including PubMed, Ovid, Scopus and Embase in order to collate all research evidence on the above mentioned variables.

Results

Thoraflex™ Hybrid Plexus seems to yield optimum aortic remodeling by promoting maximum false thrombosis as well true lumen expansion. Thoraflex Hybrid™ is also associated with the lowest incidence of dSINE post-FET relative to the other FET devices on the market. Aortic remodeling and dSINE do influence each other and are both linked with FET graft length and size.

Conclusion

The FET technique for TAR shows excellent aortic remodeling but is associated with a considerable risk of dSINE development. However, Thoraflex™ Hybrid has demonstrated itself to be the superior FET device on the aortic arch prostheses market. Since aortic remodeling, dSINE, FET insertion length and stent graft size are all interconnect, the choice of FET device length and size must be made with great care for optimum results.

Hybrid Technique on the Total Arch Replacement for Type A Aortic Dissection: 12-year Clinical and Radiographical Outcomes From a Single Center

Objective

Hybrid total arch replacement (HTAR) was an alternative for type A aortic dissection (TAAD). This study aimed to evaluate the clinical and radiographical outcomes of HTAR for TAAD and to evaluate the clinical outcomes of performing this procedure under mild hypothermia.

Methods

A total of 209 patients who underwent HTAR for TAAD were retrospectively analyzed and stratified into mild (n = 48) and moderate (n = 161) hypothermia groups to evaluate the effects of mild hypothermia on the clinical outcomes. Long-term clinical outcomes were evaluated by the overall survival and adverse aortic events (AAEs). A total of 176 patients with preoperative and at least one-time postoperative aortic computed tomography angiography in our institute were included for evaluating the late aortic remodeling (aortic diameter and false lumen thrombosis).

Results

The median follow-up period was 48.3 (interquartile range [IQR] = 28.4–73.7) months. The overall survival rate was 88.0, 83.2, and 77.1% at the 1, 5, and 10 years, respectively, and in the presence of death as a competing risk, the cumulative incidence of AAEs was 4.8, 9.9, and 12.1% at the 1, 5, and 10 years. The aortic diameters were stable in the descending thoracic and abdominal aorta (P > 0.05 in all the measured aortic segments). A total of 100% complete false lumen thrombosis rate in the stent covered and distal thoracic aorta were achieved at 1 year (64/64) and 4 years (18/18), respectively after HTAR. The overall composite adverse events morbidity and mortality were 18.7 and 10.0%. Mild hypothermia (31.2, IQR = 30.2–32.0) achieved similar composite adverse events morbidity (mild: 14.6 vs. moderate: 19.9%, P = 0.41) and early mortality (mild: 10.4 vs. moderate: 9.9%, P = 1.00) compared with moderate hypothermia (median 27.7, IQR = 27–28.1) group, but mild hypothermia group needed shorter cardiopulmonary bypass (mild: 111, IQR = 93–145 min vs. moderate: 136, IQR = 114–173 min, P < 0.001) and aortic cross-clamping (mild: 45, IQR = 37–56 min vs. moderate: 78, IQR = 54–107 min, P < 0.001) time.

Conclusion

Hybrid total arch replacement achieved desirable early and long-term clinical outcomes for TAAD. Performing HTAR under mild hypothermia was as safe as under moderate hypothermia. After HTAR for TAAD, dissected aorta achieved desirable aortic remodeling, presenting as stable aortic diameters and false lumen complete thrombosis. In all, HTAR is a practical treatment for TAAD.

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.

Morphometric predictors of aortic remodeling after frozen elephant trunk repair of type A dissection

OBJECTIVES

We analyzed the predictors of postoperative aortic remodeling after the frozen elephant trunk technique for type A dissection.

METHODS

This retrospective study cohort comprised 20 patients who underwent the frozen elephant trunk technique for type A dissection. The incidence of aortic remodeling was evaluated at four levels: middle of the frozen elephant trunk, distal end of the frozen elephant trunk, 10th thoracic vertebra, and proximal to the celiac artery. Several parameters of the residual dissected aorta were analyzed at these four levels, and the predictors of aortic remodeling were investigated.

RESULTS

The incidence of aortic remodeling was 85% at the middle of the frozen elephant trunk, 70% at the distal end of the frozen elephant trunk, 50% at the 10th thoracic vertebra, and 35% proximal to the celiac artery. In a total of 80 computed tomography images, there were significant differences between the aortic remodeling and non-remodeling groups in the true lumen diameter, false lumen diameter, true lumen/aortic diameter ratio, true lumen area, true lumen/aortic area ratio, and two parameters explaining the shape of the true lumen (created using elliptic Fourier analysis). Multivariate analysis revealed that the independent predictors of aortic remodeling were the true lumen/aortic area ratio and principal component 1.

CONCLUSIONS

There were high incidences of aortic remodeling at the middle and distal end of the frozen elephant trunk. Multivariate analysis showed that the true lumen/aorta area ratio and the shape of the true lumen may be important predictors of aortic remodeling.

Hybrid Approach in Acute and Chronic Aortic Disease

The management of patients with aortic disease that involves the ascending aorta, the aortic arch, and the descending aorta represent a surgical challenge. Open surgical repair remains the gold standard for aortic arch pathologies. However, this operation requires a cardiopulmonary bypass and a period of profound hypothermia and circulatory arrest, which carries a substantial rate of mortality and morbidity. For these reasons, hybrid arch repair that involves a combination of open surgery with endovascular aortic stent graft placement has been introduced as a therapeutic alternative for those patients deemed unfit for open surgical procedures. Hybrid repair requires varying degrees of invasiveness and can be performed as a single-stage procedure or as a two-stage procedure. The choice of the technique is multifactorial, depending on the characteristics of the diseased arch with regard to position of the stent graft proximal landing zone, patient fitness and comorbid status, as well as surgical expertise and hospital facilities. Among the evolving hybrid procedures is the so-called “frozen” or stented elephant trunk technique. Adapted from the classical elephant trunk technique, this approach facilitates the repair of a concomitant aortic arch and proximal descending aortic aneurysms in a single stage under circulatory arrest. This technique is increasingly being used to treat extensive thoracic aortic disease and has shown promising results.

Distal Stent Graft-Induced New Entry after Total Arch Replacement with Frozen Elephant Trunk for Aortic Dissection

Objectives: Distal stent graft-induced new entry (dSINE), defined as a new tear caused by a stent graft, has been increasingly observed following total arch replacement using frozen elephant trunk (FET) for aortic dissection. We aimed to investigate the incidence and treatment of dSINE after the use of FET. Methods: This retrospective study evaluated 70 patients who underwent total arch replacement using FET for aortic dissection between August 2014 and March 2020. They were followed up for at least 6 months postoperatively. Between-group comparisons were performed between those who did and did not develop dSINE. The risk factors for the development of dSINE and the treatment of dSINE were analyzed. Results: dSINE occurred postoperatively in nine patients (12.9%) with a median time frame of 17.7±11.7 months. The incidence of dSINE did not differ significantly according to classification, phase of dissection, or oversizing. All patients in the dSINE group developed enlargement of the false lumen. dSINE closure was successfully achieved without complications via thoracic endovascular aortic repair (TEVAR) in all patients. Conclusion: No independent factors predicting the development of dSINE were noted in this study. Additional TEVAR for dSINE provides good results and achieves false lumen thrombosis in the thoracic aorta, with no complications.

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.

A new dissection-specific hybrid stent graft for patients with DeBakey type I aortic dissection

OBJECTIVES

We present our first experience of using a new dissection-specific hybrid stent graft (SG) (the 'Soft Elephant Trunk') in the frozen elephant trunk technique, in patients with non-acute DeBakey type I aortic dissection.

METHODS

Between September 2016 and February 2021, patients with non-acute DeBakey type I aortic dissection underwent the frozen elephant trunk procedure at our centre using 3 SG types: group Z used stiff, distal Z-shaped nitinol SGs (E-Vita, Medtronic); group R used a stiff, ring-shaped nitinol SG (Thoraflex); and group S used a soft, distal dissection-specific SG. Predictors of distal SG-induced new entry were analysed. End points were hospital- and midterm-follow-up results.

RESULTS

The study comprised 109 patients with 46 (42.2%), 22 (20.2%) and 41 (37.6%) patients in groups Z, R and S, respectively. No significant differences were found in early outcomes. Freedom from distal SG-induced new entry was comparable in groups Z, R and S (68.9% vs 92.9% vs 100%, log-rank = 0.14). There was no significant difference in follow-up between the groups. Four-year survival rates were 80.44%, 71.59% and 95.06% in groups Z, R and S, respectively. On multivariable analysis, the presence of connective tissue disorders [hazard ratio (HR) = 5.62, P = 0.11] and SG diameter (HR = 1.37, P = 0.034) were strong predictors of distal SG-induced new entry.

CONCLUSIONS

Dissection-specific hybrid SG with a soft distal end is effective in patients with non-acute DeBakey type I aortic dissection. Compared to non-soft distal SGs, this can reduce the incidence of distal complications. Long-term outcomes are necessary to determine the potential advantages and disadvantages of the new prosthesis.

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.

Aortic remodelling and false lumen changes after the frozen elephant trunk technique using the thoraflex hybrid stented graft for aortic dissection

Background

Despite the marked improvement in the aortic dissection repair techniques, residual dissected aorta with a patent false lumen remains an issue. So, the aim of our study is to observe the effect of inserting the Thoraflex Hybrid Graft on the aortic diameters in patients with type A aortic dissection involving the arch and descending aorta. Patients with type I aortic dissection who had aortic dissection repair using the Thoraflex Hybrid Graft in University Hospitals Birmingham were studied. Radiological assessment with computed tomography of the aorta was done at the level of the diaphragm to measure the true lumen, false lumen and total aortic diameters. Significance of change of diameters at early post-operative as compared to the pre-operative period was analysed.

Results

Eight cases were done in the acute setting, while 14 cases were done in the chronic setting. The ratio of true lumen to the total aortic diameter has significantly increased in the follow-up period as compared to the pre-operative period (P = 0.031). Whereas false lumen to total aortic diameter ratio has significantly decreased (P = 0.024). Subgroup analysis revealed that these changes were not significantly altered by whether the dissection was acute or chronic.

Conclusions

The Thoraflex Hybrid Graft will induce positive aortic remodelling with expansion of true lumen and will diminish the false lumen. But we could not find a significant difference between acute or chronic cases due to small sample size.

Post-implantation syndrome after frozen elephant trunk is associated with the volume of new-onset aortic thrombus

Background

Post-implantation syndrome (PIS) is defined as non-infectious continuous fever and a concomitant rise in inflammatory markers shortly after endovascular aortic repair. PIS occurrence after hybrid procedures, such as the frozen elephant trunk (FET) technique, has not been adequately investigated. The current study aims to define the incidence of PIS after the FET and to identify possible risk factors associated with its occurrence.

Methods

The clinical charts of 59 patients undergoing the FET between February 2015 and April 2020 were reviewed retrospectively. The occurrence of PIS was defined as the presence of fever (>38 °C lasting longer than one day during the hospitalisation) and leucocytosis (white blood cell count >12,000/µL). Patients with concomitant conditions possibly leading to fever and/or leucocytosis were excluded. Beside demographic and procedure-related data, serum/plasma inflammatory markers were evaluated before surgery and daily up to seven days postoperatively. Computed tomography scans (CT) were examined to calculate the volume of pre-existent and new-onset mural thrombus after the FET.

Results

Thirty-eight patients met the inclusion criteria. The study cohort was divided into two groups based on the occurrence of PIS (17 cases; 44.7%). Patients with PIS were significantly younger than those without PIS (53.5±8.9 vs. 62.5±9.6 years; P=0.005). Female patients were less likely to develop PIS (5.2% vs. 26.3%, P=0.018). Patients with PIS had a higher volume of new-onset thrombus in the postoperative CT (P<0.001). Patients treated for post-dissection aneurysm had, postoperatively, significantly more thrombus material developed in a false lumen (P=0.02). Among the PIS markers, CRP (C-reactive protein) levels on the third postoperative day were independently associated with the volume of new-onset thrombus (P=0.011). After multivariate analysis, the volume of new-onset thrombus (P=0.028) and age (P=0.036) remained the variable associated with a statistically significant increased incidence of PIS.

Conclusions

PIS can occur after the frozen elephant trunk procedure. The volume of new-onset thrombus seems to be associated with an increased incidence of PIS. These findings need to be confirmed in larger patient cohorts.

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.

Open or endovascular treatment of downstream thoracic or thoraco-abdominal aortic pathology after frozen elephant trunk: perioperative and mid-term outcomes

OBJECTIVES

The aim of this study was to evaluate the outcomes of open and endovascular treatment of downstream thoracic or thoraco-abdominal aortic pathology in patients who underwent previous frozen elephant trunk (FET).

METHODS

Data were retrieved to evaluate mortality, cardiac, pulmonary, cerebrovascular, renal and spinal cord major adverse events, early- and mid-term reintervention and survival rates. The Society for Vascular Surgery endovascular reporting standards were used.

RESULTS

From 2011 to 2020, 48 patients (36 males, median age 60 years) underwent downstream aortic repair at a median of 18 months (interquartile range: 6-57) after the initial FET. Twenty-eight patients (58.3%) received open and 20 (41.7%) endovascular repair. The overall 30-day mortality was 6.3% and the initial clinical success was 88%, with no inter-group differences (P = 0.22 and 0.66 respectively). Six spinal cord deficits were recorded (13%): 3 (6.3%) were permanent. The major adverse events incidence was lower in the endovascular cohort [4 (20%) vs 14 (50%); P = 0.047], mainly due to a lower rate of grade ≥2 respiratory complications (5% vs 42.9%; P = 0.004). Assisted primary clinical success at 5 years was higher in the endovascular group (95% vs 68%, P = 0.022); freedom from reintervention at competing risk analysis (P = 0.3) and overall survival at Kaplan-Meier curves (log-rank P = 0.29) were similar.

CONCLUSIONS

Downstream aortic repair after FET is feasible with both open and endovascular repair with acceptable mortality and permanent paraplegia rates. The endovascular approach has potential perioperative and mid-term advantages, but long-term durability has to be further investigated in larger cohorts.

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.

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.

Extended thoracic endovascular aortic repair for residual aortic dissection after type A aortic dissection repair

OBJECTIVE

We investigated the outcomes of extended coverage of the descending thoracic aorta by thoracic endovascular aortic repair (TEVAR) for residual chronic type B aortic dissection after type A aortic dissection (TAAD) repair.

METHODS

From November 2015 to August 2020, 36 patients underwent extended TEVAR for residual intimal tear after TAAD repair. We specifically investigated the methods and outcomes of this procedure.

RESULTS

TEVAR consisted of isolated TEVARs (n = 29), single-vessel debranching TEVAR (6), and two-vessel debranching TEVAR (1). The mean time from TAAD repair to TEVAR was 27 ± 33 months (2-86 months). The TEVAR devices used were Valiant (28 cases), GORETAG (4), Relay plus (2), and TX2 (2). Technical success of TEVAR was 100%. The distal ends of the stent grafts were T 8 (1 case), T 9 (5), T 10 (6), T 11 (9), and T 12 (15), with an average of T 11 ± 1. The average length of hospital stay after TEVAR was 9 ± 3 days (5-17 days). There were no surgical/hospital deaths or complications. The average postoperative follow-up period was 21 ± 15 months without death or reintervention.

CONCLUSIONS

The short-term outcomes of extended TEVAR for residual chronic type B aortic dissection after TAAD repair were acceptable without perioperative SCI. Aggressive descending thoracic aorta coverage may prevent aortic events, and extended TEVAR may be a preemptive treatment for the downstream aorta. Mid- to long-term results should be clarified.

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.

Distal Remodeling After Operations for Extensive Acute Aortic Dissection

BACKGROUND

The clinical predictors of distal aortic remodeling (DAR) after various procedures for extensive acute aortic dissection are not fully understood.

METHODS

From 2008 to 2018, a total of 122 candidates with extensive acute type A and B aortic dissections survived operations of total arch replacement plus frozen elephant trunk (n = 36), ascending aortic replacement plus supraaortic debranching plus retrograde stenting (hybrid procedure; n = 25), and total endovascular repair (n = 61). We assessed DAR at 4 thoracoabdominal aortic levels based on true lumen expansion, false lumen patency, maximal aortic area, and the blood supply of major branches. Univariate and multivariate logistic and mixed-effect models were performed to delineate patterns and risks for DAR at midterm follow-up.

RESULTS

At 3.9 years, 13 aorta-related adverse events (10.7%; including 3 aortic-related deaths [2.5%]) and 8 aortic reinterventions (6.6%) occurred. Follow-up computed tomography angiography was performed in all patients at 3.3 years (interquartile range, 2.7-4.4 years). The degree of DAR, which was relatively independent among aortic levels, was maximal at the pulmonary bifurcation level (90.2% complete false lumen thrombosis) and decreased along the distal aorta. Analyses of longitudinal data indicated that baseline overall false lumen patency was the only available factor to predict DAR at all 4 aortic levels. Dissection type, surgical technique, implant size, and medication did not sufficiently influence DAR at midterm follow-up.

CONCLUSIONS

After distinct operations for extensive acute aortic dissection, DAR beyond the stent graft coverage is a local anatomical behavior independent of dissection type or proximal management.

Comparative study of the frozen elephant trunk and classical elephant trunk techniques to supplement total arch replacement for acute type A aortic dissection†

OBJECTIVES

In patients with acute type A aortic dissection, the use of the frozen elephant trunk (FET) procedure with total arch replacement (TAR) has been indicated for emergency operations to obtain thrombosis of the distal false lumen (FL). However, data comparing the FET and the classical elephant trunk (CET) procedures, including the incidences of mortality, morbidity, spinal cord injury and aortic remodelling, have not yet been reported. The goal of this study was to compare the early outcomes of TAR with the FET and the CET procedures.

METHODS

The past 7 years of medical records of 323 patients with type A aortic dissection who underwent emergency surgery were reviewed retrospectively, and 148 patients who underwent TAR were shortlisted for the study. First, the patients were divided into 2 groups, the CET group (n = 115; age 65 ± 12 years) and FET group (n = 33; 67 ± 11 years), to compare the early operative outcomes, including mortality and morbidity. Second, 86 patients (CET 56; FET 30) fulfilling the inclusive criteria (inserted length of elephant trunk ≥5 cm, involvement of dissection at the descending aorta and sufficient computed tomographic evaluation at ≥6 months after the operation) were compared to evaluate the patency and diameter of the FL at each segment of the downstream aorta.

RESULTS

The in-hospital mortality rate was 8.1% (12/148), without significant differences between the 2 groups (CET 8.7% vs FET 6.1%; P = 1). No spinal cord ischaemia was encountered in either group. The incidence of postoperative FL patency at the level of the left lower pulmonary vein was 30% in the FET group, which was significantly lower than that in the preoperative state (73%) and in the CET group (77%). The downsizing of the aortic diameter at the distal edge of the CET or the FET, the left lower pulmonary vein and the coeliac axis was significant in the FET group 6 months after TAR.

CONCLUSIONS

According to our initial experience, the FET compared to the CET procedure showed comparable early complications and an advantage concerning FL thrombosis and aortic remodelling at early follow-up examinations.

The fate of the downstream aorta after open aortic repair for acute DeBakey type I aortic dissection: total arch replacement with elephant trunk technique versus non-total arch replacement†

OBJECTIVES

The aim of this study was to evaluate the fate of the downstream aorta following open aortic repair for acute DeBakey type I aortic dissection comparing total arch replacement (TAR) with the elephant trunk (ET) technique versus non-total arch replacement (non-TAR).

METHODS

From October 1999 to December 2016, 267 patients underwent open repair for acute DeBakey type I aortic dissection. A tear-oriented strategy was mainly used to determine the extent of graft replacement. Hospital mortality was 10.0% (12/120 patients) in the TAR group and 17.0% (25/147 patients) in the non-TAR group (P = 0.070). Late outcomes were compared in 230 hospital survivors (TAR: n = 108 and non-TAR: n = 122). Mean follow-up was 6.5 ± 4.6 years. The aortic diameters were measured at 4 levels, across 6 time points using computed tomography.

RESULTS

Freedom from additional aortic surgery for distal dilation was significantly better in the TAR group than the non-TAR group (TAR: 97.5 ± 1.8% at 5 years and non-TAR: 88.2 ± 3.4% at 5 years, P = 0.045). Freedom from a distal aortic event was also significantly better in the TAR group compared with the non-TAR group (TAR: 97.2 ± 1.6% at 5 years and non-TAR: 80.7 ± 4.2% at 5 years, P = 0.013). In the non-TAR group, the aortic arch diameter significantly increased (P < 0.001). Significant aortic remodelling occurred at the proximal descending aorta in the TAR with ET group (P < 0.001).

CONCLUSIONS

The TAR with ET reduced the need for additional distal aortic repair compared to non-TAR. TAR with ET prevented unfavourable aortic growth in both the aortic arch and the proximal descending aorta.

Single-center experience with the frozen elephant trunk procedure in 111 patients with complex aortic disease

Background

The frozen elephant trunk (FET) technique is increasingly used for the treatment of acute and chronic aortic arch disease. This study reports our single center experience with the FET technique in patients with complex aortic disease.

Methods

Between 2009 and 2019, 111 consecutive patients underwent aortic arch surgery in our institution using the FET technique for acute type A dissection (AAD group; n=75) or non-acute type A dissection (non-AAD group; n=36; 10 patients with chronic type A dissection; 26 patients with aneurysm), respectively. Relevant perioperative data, including 30-day mortality and neurological complications, were retrospectively obtained from our electronic patient’s records, including follow-up (FU) data of outpatient clinical visits and computed tomography (CT).

Results

Thirty-day mortality in the entire FET cohort was 16.2% (AAD 18.7% vs. non-AAD 11.1%; n=0.414). Severe brain injury was the leading cause of death in AAD patients (12.0% vs. 0% non-AAD; P=0.030). Overall permanent stroke and spinal cord injury was 12.6% and 3.6%. Four patients in the AAD group developed paraplegia and permanent stroke rate was significantly higher in AAD compared to non-AAD patients (17.3% vs. 2.8%; P=0.034). One, 3- and 5-year survival rates were 78.7%±4.0%, 72.2%±4.8%, and 64.3%±6.8% for the total cohort; survival at 1-, 3- and 5-year was 76.7%±5.0%, 71.0%±6.1%, and 64.5%±8.3% for the AAD cohort compared to 83.1%±6.3%, 75.0%±7.9% and 66.7% for non-AAD patients (P=0.579), respectively.

Conclusions

Our single-center experience confirms good early and mid-term survival after the FET procedure in patients presenting with AAD, CAD and aneurysm. Future efforts should focus on reduction of severe neurological complication.