Training in Aortic Arch Surgery as a Blueprint for a Structured Educational Team Approach: A Review.

Background and objectives: The treatment of pathologies of the aortic arch is a complex field of cardiovascular surgery that has witnessed enormous progress recently. Such treatment is mainly performed in high-volume centres, and surgeons gain great experience in mastering potential difficulties even under emergency circumstances, thereby ensuring the effective therapy of more complex pathologies with lower complication rates. As the numbers of patients rise, so does the need for well-trained surgeons in aortic arch surgery. But how is it possible to learn surgical procedures in a responsible way that, in addition to surgical techniques, also places particular demands on the overall surgical management such as perfusion strategy and neuro-protection? This is why a good training programme teaching young surgeons without increasing the risk for patients is indispensable. Our intention was to highlight the most challenging aspects of aortic arch surgery teaching and how young surgeons can master them. Materials and Methods: We analysed the literature to find out which methods are most suitable for such teaching goals and what result they reveal when serving as teaching procedures. Results: Several studies were found comparing the surgical outcome of young trainees with that of specialists. It was found that the results were comparable whether the procedure was performed by a specialist or by a trainee assisted by the specialist. Conclusions: We thus came to the conclusion that even for such a complex type of intervention, the responsible training of young surgeons by experienced specialists is possible. However, it requires a clear strategy and team approach to ensure a safe outcome for the patient.

Total arch replacement versus proximal aortic replacement in acute type A aortic dissection: Aggressive versus conservative.

BACKGROUND: Acute type A aortic dissection (ATAAD) is a life-threatening medical condition requiring urgent surgical attention. It is estimated that 50% of ATAAD die within 24 h of onset, with the mortality rate is increasing by 1%-2% every additional hour without prompt intervention. A variety of ATAAD surgical repair techniques exist which has sparked controversy within the literature, with the main two strategies being proximal aortic replacement (PAR) and total arch replacement (TAR). Nevertheless, the question of which of these two strategies if the more optimal is still debatable. AIMS: This commentary aims to discuss the recent study by Sa and colleagues which presents a pooled analysis of Kaplan-Meier-derived individual patient data from studies with follow-up comparing aggressive (TAR) and conservative (PAR) approaches to manage ATAAD patients. METHODS: A comprehensive literature search was performed using multiple electronic databases including PubMed, Ovid, Google Scholar, EMBASE, and Scopus to collate the relevant research evidence. RESULTS: The more aggressive TAR approach for treating ATAAD seems to yield more favorable results including more optimal long-term survival as well as a lower need for reoperation. The frozen elephant trunk (FET) technique can be considered the mainstay TAR technique. CONCLUSION: It is valid to conclude that TAR with FET is the superior strategy for managing ATAAD patients.

The Frozen Elephant Trunk Technique for the Treatment of Type B and Type Non-A Non-B Aortic Dissection.

OBJECTIVE: To evaluate outcomes of patients with acute complicated or chronic Type B or non-A non-B aortic dissection who underwent the frozen elephant trunk (FET) technique. METHODS: Between April 2013 and July 2019, 41 patients presenting with acute complicated (n = 29) or chronic (n = 12) descending thoracic aortic dissection were treated by the FET technique, which was the treatment of choice when supra-aortic vessel transposition would not suffice to create a satisfactory proximal landing zone for endovascular aortic repair, when a concomitant ascending or arch aneurysm was present, or in patients with connective tissue diseases. RESULTS: One patient (2%) died intra-operatively secondary to an aortic rupture in dwnstream aortic segments. No post-operative deaths occurred. Four patients (10%) suffered a non-disabling posto-operative stroke and were discharged with no clinical symptoms (modified Rankin Scale [mRS] 0, n = 1), no significant disability (mRS 1, n = 2), or with slight disability (mRS 2, n = 1). No spinal cord ischaemia was observed. The primary entry tear was either surgically resected or excluded from circulation in all patients. During follow up, one patient (2%) died after two years (not aorta related) and 16 patients (39%) underwent an aortic re-intervention after 7.7 [interquartile range 0.7, 15.8] months (endovascular aortic repair: n = 14; open thoraco-abdominal aortic replacement: n = 1, hybrid approach: n = 1). CONCLUSION: The FET technique is an effective treatment option for acute complicated and chronic Type B or non-A non-B aortic dissection in patients in whom primary endovascular aortic repair is non-feasible. While the post-operative outcome is acceptable with a relatively low incidence of non-disabling strokes, this study also underlines the considerable need for aortic re-interventions. Continuous follow up of all patients undergoing the FET procedure is essential.

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.

Risk factors, prevention, and therapy of intraluminal stent thrombosis in frozen elephant trunk prostheses-what we know so far.

Intraluminal thrombus formation (ILT) is a recently discovered and highly clinically relevant complication after frozen elephant trunk implantation in cardiovascular surgery. In this phenomenon, a thrombus forms within the lumen of the stent graft component of the frozen elephant trunk prosthesis and puts the patient at risk for downstream embolization with visceral or lower limb ischemia. Incidence of ILT reported in the currently available studies ranges from 6% to 17% of patients after frozen elephant trunk implantation. Adverse thromboembolic events include acute occlusion of the celiac and superior mesenteric arteries, both renal arteries as well as acute lower limb ischemia due to iliac or femoral artery embolization that not infrequently require interventional or open embolectomy. Therefore, the presence of ILT is associated with increased short-term mortality and morbidity. Currently proposed strategies to avoid ILT formation include a more aggressive anticoagulation management, minimization of postoperative coagulation factor application, and even technical optimizations of the stent graft portion itself. If ILT is manifested, the therapeutic strategies tested to date are long-term escalation of anticoagulation and early endovascular extension of the FET stent graft with overstenting of the intraluminal thrombus. The long-term efficiency of these prophylactic and therapeutic measures has yet to be proven. Nonetheless, all surgeons performing the frozen elephant trunk procedure must be aware of the risk of ILT formation to facilitate a timely diagnosis and therapy.

Major adverse outcomes in patients with acute type A aortic dissection undergoing total arch replacement with frozen elephant trunk procedure.

BACKGROUND: The objective of this investigation was to identify the risk factors linked to major adverse outcomes (MAO) subsequent to total arch replacement with frozen elephant trunk procedure (TAR+FET) surgery among patients diagnosed with acute type A aortic dissection (ATAAD). Additionally, the study aimed to elucidate the influence of these adverse outcomes on the long-term prognosis of the patients. METHOD: 670 ATAAD patients received the TAR+FET procedure. Multivariable logistic regression was used to investigate the risk factors associated with in-hospital MAO. Additionally, long-term survival outcomes were assessed through follow-up observations of all patients. RESULTS: The overall in-hospital mortality was 4.33%. Among 670 patients, 169 patients (25.22%) developed postoperative MAO. Multivariate analysis showed that in-hospital MAO was positively associated with age (OR = 1.025, 95%CI: 1.005-1.045, P = 0.014), lower limb symptoms (OR = 2.562, 95%CI: 1.407-4.666, P = 0.002), involvement of coronary artery (OR = 2.027, 95%CI: 1.312-3.130, P = 0.001), involvement of left renal artery (OR = 1.998, 95%CI: 1.359-2.938, P < 0.001), CPB time (OR = 1.011, 95%CI: 1.007-1.015, P < 0.001) and WBC counts (OR = 1.045, 95%CI: 1.007-1.083, P = 0.019). MAO group showed a worse long-term prognosis than those non-MAO group (P = 0.002). CONCLUSIONS: While TAR+FET can be an effective treatment option for ATAAD patients, careful patient selection and management are essential in minimizing the risk of MAO and ensuring long-term success.

Is a four-branched prosthesis advantageous over a straight prosthesis in Frozen elephant trunk surgery?

For years, the elephant trunk (ET) technique has been applied to extended aortic arch pathology facilitating staged downstream open- or endovascular completion. The recent use of a stentgraft as so-called frozen ET enables even single-stage repair, or its use as a scaffold in an acutely or chronically dissected aorta. Hybrid prosthesis have since been introduced, available as either a 4-branch graft or a straight graft for reimplantation of the arch vessels using the classic island technique. Both techniques are known to have technical advantages and disadvantages in specific surgical scenarios. In this paper we will discuss whether a 4-branch graft hybrid prosthesis is advantageous over a straight hybrid prosthesis. Our considerations in terms of mortality, cerebral embolic risk, myocardial ischemia time, cardiopulmonary bypass (CPB) time, hemostasis and exclusion of supra-aortic entries in the case of acute dissection will be shared. The 4-branch graft hybrid prosthesis conceptually facilitates reduced systemic-, cerebral-, and cardiac arrest time. Additionally, atherosclerotic ostial debris, intimal re-entries, and fragile aortic tissue in genetic disease can be excluded by using a branched graft instead of the island technique for reimplantation of the arch vessels. Despite many conceptual technical advantages of the 4-branch graft hybrid prosthesis, literature data do not show significantly better outcomes when compared to the straight graft, to support its routine use in all cases.

Implantation of frozen elephant trunk (FET)-surgical technique-Thoraflex.

The development of the frozen elephant trunk (FET) prosthesis has revolutionised how we treat some of the most complex aortic pathology, including in the emergency setting of acute type A aortic dissection. The design of the prosthesis is fundamental to the success of the procedure in combination with the surgeon's skill in interpreting the pre-operative scan and procedural planning to juggling the technical aspects of the deployment and reimplantation of the supra-aortic vessels. Furthermore, organ protection strategies and techniques to reduce the complications of neurological and renal impairment are paramount. This article focuses on the Thoraflex Hybrid prosthesis including the evolution of the concept, design features unique to the device and surgical technique including fundamentals of sizing and implantation steps with illustrations. The Thoraflex Hybrid prosthesis provides an ergonomic and neat delivery system with a trusted gelatin coated surgical graft material making implantation and use as straightforward as possible. These features have meant that the device is a market leader in the field of FETs with outcome data and implant figures to support its efficacy globally. The success of the device is also reflected in the literature. For example, in the UK study from Mariscalco et al., the mortality of FET implantation in acute type A dissection, of which most were using the Thoraflex device, was only 12%. This is comparable to leading centres in Europe with the inherent advantage of improving long-term outcomes in addition. Of course, this strategy is not appropriate in all cases and precise judgement of when to deploy a FET in both the emergency and elective setting is key to achieving good outcomes.

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

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

Comparative Study of Male and Female Patients Undergoing Frozen Elephant Trunk Total Arch Replacement.

BACKGROUND: Our aim was to investigate outcomes and long-term survival in male and female patients after frozen elephant trunk (FET) total arch replacement. METHODS: Between March 2013 and January 2023, 362 patients underwent aortic arch replacement via the FET technique. We compared patient characteristics and intra- and postoperative data between male and female patients. RESULTS: Male patients were significantly younger (p = 0.012) but revealed a higher incidence of coronary artery disease (p = 0.008) and preoperative dialysis (p = 0.017). More male patients presented with type A aortic dissections (p = 0.042) while more female patients had aortic aneurysms (p = 0.025). The aortic root was replaced in significantly more male patients (p = 0.013), resulting in significantly longer cardiopulmonary bypass duration (p < 0.001) and operative times (p < 0.001). There were no statistically significant differences in postoperative outcome parameters including in-hospital mortality (p = 0.346). However, new in-stent thrombus formation was significantly more frequent in female patients (p = 0.002). Age in years (odds ratio (OR): 1.026, p = 0.049), an acute pathology (OR: 1.941, p = 0.031) and preoperative dialyses (OR: 3.499, p = 0.010) were predictive for long-term mortality in our Cox regression model, sex (p = 0.466) was not. There was no statistical difference in overall survival (log rank: p = 0.425). CONCLUSIONS: Female patients are older but reveal fewer cardiovascular risk factors; aneurysms are more common in female than male patients. As female patients undergo concomitant surgical procedures less often, their operative times are shorter. While survival and outcomes were similar, female patients suffered from postoperative new in-stent thrombus formation significantly more often.

Analysing debranching techniques in Frozen Elephant Trunk procedures: a narrative literature review.

Background and Objective: Since 2003, the Frozen Elephant Trunk (FET) technique has attained rising popularity for treating extensive aortic arch pathologies such as acute and chronic aortic dissection, as well as thoracic aortic aneurysm. Conventionally, the FET procedure included a complete resection of the aortic arch and, subsequently, a distal aortic anastomosis of the prosthetic part of the hybrid graft in arch zone 3. Simultaneous to the introduction of the FET technique, the traditional Elephant Trunk technique was simplified by adding debranching techniques which allows for proximalization of the distal aortic anastomosis. Nowadays, modern concepts of aortic arch surgery combine the FET technique with proximalization of the distal anastomosis in arch zone 2 or further proximal, achieved by using different debranching techniques. This review describes different debranching techniques to facilitate arch reconstruction, and aims to critically assess the outcomes and potential clinical advantages of proximalization using debranching in FET surgery. Methods: We conducted a search using the PubMed and Google Scholar electronic databases to evaluate published outcomes of different debranching techniques. An overview of the data synthesis of 21 included studies is reported. Key Content and Findings: Most studies report numeric, but not statistically significant improved outcomes after debranching in FET surgery for mortality, neurological complications, spinal cord injury, kidney failure, bowel ischemia and recurrent nerve palsy. Some studies report statistically significant improved results in isolated endpoints such as neurological, bowel ischemia, and recurrent nerve palsy. Most studies report debranching to be technically easier, but this is difficult to objectively assess and measure. Conclusions: There is an improved numeric outcome of different debranching techniques with proximalization of the distal anastomosis, but without reaching statistical significance. This review shows marked heterogeneity across included studies and highlights the scarce use of existing guidelines in clinical research of open aortic arch surgery as proposed by the International Aortic Arch Surgery Study Group. Furthermore, this review demonstrates the urgent need for multicenter registries or studies to be able to compare the outcome of different surgical techniques for various aortic arch pathologies.

Distal stent graft-induced new entry (dSINE) after frozen elephant trunk: a scoping review.

Background: The introduction of hybrid total arch replacement with the frozen elephant trunk (FET) technique has improved the field of aortic surgery by allowing single-stage treatment of complex aortic pathologies. Although FET has been associated with favorable aortic remodeling, it is also associated with the potential development of distal stent graft-induced new entries (dSINEs). The aim of our review is to collect data about the incidence and the supposed conditions for the occurrence of dSINE after total hybrid arch replacement with FET technique. Methods: The literature review was performed using PubMed databases from inception to January 2022. A descriptive approach to detect and display supposed risk factors and predictors for dSINE occurrence has been adopted. Results: Eight studies summarized the state-of-the-art of dSINE in a total number of 544 FET procedures performed to treat acute and chronic aortic dissections. The scoping review showed dSINEs occurrence in 69 patients (12.7%). The mean time between surgery and the diagnosis ranged from 12.6 to 30.6 months. Most patients that developed dSINE received endovascular treatment, whereas a couple of them needed open surgery. According to our experience, from January 2007 to December 2021, in 225 FET procedures a total of 54 cases of dSINE, both with Thoraflex and E-vita grafts have been detected. The mean time between the surgical procedure and the diagnosis was 27.2±33.6 months. Conclusions: dSINEs are frequent complications after FET. Although not emergent, they require proper treatment. Due to dSINE's asymptomatic nature and potential harm, a rigorous follow-up including angio-computed tomography (CT) should be planned.

Standardized in vitro bleeding tests in a non-coated novel hybrid prosthesis for frozen elephant trunk demonstrates minimal oozing during full heparinization, supported by clinical data.

Introduction: Recent reports have questioned the blood impermeability of the novel frozen elephant trunk (FET) device E-vita Open NEO© (EO-NEO). Therefore, standardized in vitro bleeding tests using porcine heparinized blood were performed, as well as stress testing on the blood tightness of the collar suture line, to investigate this observation. Material and methods: EO-NEO prostheses were examined in vitro for blood permeability in three test series. Initially, antegrade perfusion with heparinized porcine blood [activated clotting time (ACT) of 500 s, with a 60 min duration] was performed, followed by ante/retrograde testing via the EO-NEO side port. Testing of the collar suture line under a tension of 10 Newton (N) within a suspension device (blood pressure 120 mmHg, ACT of 560 s, 1 min duration) was carried out with the suture material force fiber white (FFWs) yarn, using standard fixation (5 stitches/cm), FFWh yarn in hemostatic fixation (15 stitches/cm), and flow weave yarn (FWYh). Results: Blood permeability testing of EO-NEO through the prosthetic lumen or via the side port demonstrated minor leakage without statistical difference between the standard and hemostatic suture lines or suture materials used, or positioning on the crimped or tapered portion (p > 0.05). The specific collar anastomosis testing demonstrated leakage volumes of 140 ml/min for FFWs vs. 16 ml/min for FFWh (p = 0.02), vs. 9 ml/min with the FWYh (p = 0.01). Conclusion: Different blood leakage tests showed minimal oozing and no difference in blood loss through the fabric and different collar suture lines, but unphysiological pressurized retrograde perfusion of the collar region showed significantly less leakage using FWYh and FFWh, prompting production modification of EO-NEO. Clinical results confirmed low blood loss using this novel FET device.

Case report: Multi-site perfusion strategy for type A acute aortic dissection complicated with cerebral malperfusion.

Acute type A dissection presenting with cerebral malperfusion has high morbidity and mortality. Given the complexity of underlying vascular involvement, it is a challenging clinical scenario. Many of these patients are not deemed surgical candidates. If surgery is considered, it often requires complex aortic arch and neck vessel reconstruction. We present a 48-year-old male with an acute type A aortic dissection that presented with paraplegia and decreased level of consciousness. A Computed Tomography showed occlusion of both common carotid arteries. He was successfully treated with a multi-site perfusion strategy and a Hybrid Frozen Elephant Trunk graft to achieve fast restoration of the cerebral circulation and minimize brain ischemia and permanent neurological damage. From this case, we learn that aggressive arch and neck vessel reconstruction supported by multi-site perfusion could help improve mortality and neurological outcomes in selected patients.

Evidence-based frozen elephant trunk practice: a narrative review.

Background and Objective: The frozen elephant trunk (FET) allows a single-stage repair of complex arch pathologies due to its stented and non-stented hybrid prosthesis (HP) features. FET inherently has its own related complications including distal stent graft-induced new entry (dSINE), failure of aortic remodelling, endoleak, reintervention, and kinking of the stent. The aim of this narrative review is to discuss the latest evidence regarding the postoperative clinical outcomes of the FET procedure. Another aim is to provide an overview of results achieved using different FET devices on the global arch prostheses market. Methods: A comprehensive literature search was conducted using multiple electronic databases to identify and extract the relevant data and information. Key Content and Findings: This review found that the literature reported a 5-12% mortality rate post-FET, with varying figures depending on the prosthesis type. Between 0-18.2% of patients developed dSINE, while 0.1-28% developed endoleak. Reintervention occurred in 0-28% of patients and the incidence of kinking has been quoted between 0-8% in the literature. Reporting aortic remodelling rates was challenging due to the lack of standardisation and various measurements reported; however, all studies included in this review reported relative increase in true lumen diameter, reduction in the false lumen diameter, and/or false lumen thrombosis. Conclusions: In conclusion, FET can achieve a favourable postoperative profile in terms of survival, complications and aortic remodelling, and remains the gold-standard treatment for thoracic aortic pathologies implicating the arch and descending thoracic aorta.

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

Background: Aortic arch pathology often requires staged segmental repairs. Total aortic arch replacement with frozen elephant trunk (FET) offers surgical options for these pathologies. The Jotec E-vita Open NEO™ branched prosthesis was introduced in 2020; we sought to share our initial experience focusing on the prosthesis selection strategies, surgical techniques, anastomosis-bleeding and graft-oozing control methods, and early clinical outcomes from two Asian centers. Methods: We performed a retrospective cohort study in patients with aortic arch pathologies who underwent total arch replacement using the FET procedure with Jotec E-vita Open NEO™ branched prosthesis from two Asian centers between October 2020 and August 2021. The primary outcome was overall 30-day mortality, and the secondary outcomes were operative complications. Results: Twenty-five consecutive patients underwent total arch replacement with FET with the novel hybrid prosthesis. Overall 30-day mortality from both centers was 0%. Overall mean operative, cardiopulmonary bypass, hypothermic circulatory arrest, and selective antegrade cerebral perfusion times were 353.4±80.5, 183.2±39.6, 57.2±14.7, and 138.2±28.6 minutes, respectively. No patient developed stroke. Permanent spinal cord injury (SCI) was recorded in one patient (4%) and one (4%) had transient lower limb weakness that resolved after spinal drainage. There was no requirement of re-sternotomy for hemostasis. Conclusions: We reported a multicenter Asian case series with the novel FET hybrid prosthesis demonstrating the feasibility and safety of promising initial clinical outcomes. The technique of circumferential reinforcement of vascular anastomosis for hemostasis may be one of the methods for lowering the rates of re-sternotomy for hemostasis, and proper surgical or transfusion strategies would overcome the excessive oozing of the prosthesis. Long-term follow-up is required for further evaluation of aortic pathology progression and device-related outcomes.

First insights into the role of wall shear stress in the development of a distal stent graft induced new entry through computational fluid dynamics simulations.

Background: Distal stent graft induced new entry (dSINE) is an emerging complication after frozen elephant trunk (FET) procedure. The aim of this computational fluid dynamics (CFD) study was to investigate the role of wall shear stress (WSS) after the development of dSINE based on hemodynamic changes. Methods: Aortic diameter and WSS of five patients who developed a dSINE after FET procedure were retrospectively analyzed before and after the occurrence of dSINE. Patient-specific 3-dimentional surface models of the aortic lumen were reconstructed from computed tomography angiographic datasets (pre dSINE: n=5, dSINE: n=5) to perform steady-state CFD simulations with laminar blood flow and zero pressure outlet conditions. WSS was calculated at the level of the stent graft (SG), the landing zone of the SG and at a location further distal to the SG, as well as on the outer and inner curvature of the aorta from SG center to its distal end. Results: Post dSINE occurrence, median WSS increased significantly from 0.87 [interquartile range (IQR): 0.83-1.03] to 1.55 (IQR: 1.09-2.70) Pa, (P=0.043) within the SG and from 1.22 (IQR: 0.81-1.44) to 1.76 (IQR: 1.55-3.60) Pa, (P=0.043) at the landing zone of the SG. A non-significant increase from 1.22 (IQR: 0.59-3.50) to 2.58 (IQR: 1.16-3.78) Pa, (P=0.686) further downstream was observed. WSS at the outer curvature of the SG was significantly higher compared to WSS at the inner curvature for dSINE. Conclusions: Adverse hemodynamic conditions in the form of elevated WSS consist inside and at the distal end of the SG as well as at the outer curvature of the aorta, which may contribute to weakening of the aortic wall. These new findings emphasize the relevance and potential of WSS in dSINE for additional adverse events, such as aortic rupture. Further prospective studies are warranted to explore if the combination of clinical parameters with WSS might be useful to decide which patients require an urgent reintervention in terms of a SG extension.

Surgical management and outcomes of coronary artery involvement secondary to acute type A aortic dissection: a retrospective cohort study.

Background: Coronary artery involvement (CAI) remains a fatal comorbidity in the context of acute type A aortic dissection (ATAAD). We evaluated the impact of CAI on the perioperative and short-term outcomes of patients with ATAAD who underwent total arch replacement (TAR) and frozen elephant trunk (FET) implantation and shared our surgical management experience with the involved coronary artery. Methods: In this retrospective cohort study, a total of 204 patients with ATAAD between June 2019 and December 2021 were enrolled and divided into the CAI group (n=67) and the non-CAI group (n=137). The characteristics of CAI lesions were described according to the Neri classification. Univariable and multivariable analyses were used to identify independent risk factors for in-hospital mortality. Survival analysis was performed using the Kaplan-Meier method and compared using the log-rank test. Results: Patients in the CAI group had a longer intraoperative duration of cardiopulmonary bypass (CPB) and cross-clamp, and experienced longer mechanical ventilation time and intensive care unit stays postoperatively. Regarding perioperative outcomes, the prevalence rates of new-onset continuous renal replacement therapy requirement (23.9% vs. 10.2%, P=0.01) and in-hospital mortality (17.9% vs. 7.3%, P=0.02) were higher in the CAI group. Coronary artery malperfusion (CAM) was an independent risk factor for in-hospital mortality. Short-term survival analysis was similar between the two groups (P=0.146). Conclusions: For patients with ATAAD undergoing TAR and FET implantation, concomitant CAI may complicate surgery and increase in-hospital morbidity and mortality. CAM secondary to CAI was identified as an independent risk factor. However, short-term survival after hospital discharge was comparable between the two groups. Coronary ostium repair is quick and operable for both type A and type B lesions, while optimal management still warrants further investigation.

Similarities, differences and unmet needs regarding prosthetic materials in aortic arch replacement using the frozen elephant trunk technique: a review.

The constant improvement of operative techniques offers the possibility of treating an increasing number of patients with complex acute and chronic thoracic aortic pathologies involving the aortic arch. Reliable and durable prosthetic material forms the platform for these approaches. Besides the most important properties like impermeability for blood, infection and thrombotic resistance, there are also properties which are not seen at first glance but can nevertheless play a key role in the healing process and long-term results, such as endothelialization and immunostimulation. To ensure the best possible properties of the graft, different variables of the grafts are continuously developed. Beside the choice of material and the weaving technique, Dacron sealing with gelatin is in clinical use for many years but is still being discussed. Collecting clinical experiences with sealed and unsealed grafts in aortic arch replacement led to the conclusion that blood loss through the prosthesis, especially in the early phase after the implantation of the graft, is lowered by gelatin sealing. Furthermore, binding of antimicrobiotic and antithrombotic agents to the collagen are promising approaches to a better prevention of these dreaded complications. More research examining the healing process of the prosthesis is needed in order to find out more about the influence of the prosthesis sealing.

Postoperative In-Stent Thrombus Formation Following Frozen Elephant Trunk Total Arch Repair.

Objectives: Our aim was to investigate the occurrence and clinical consequence of postoperative in-stent thrombus formation following the frozen elephant trunk (FET) procedure. Methods: Postoperative computed tomography angiography (CTA) scans of all 304 patients following the FET procedure between 04/2014 and 11/2021 were analysed retrospectively. Thrombus size and location were assessed in multiplanar reconstruction using IMPAX EE (Agfa HealthCare N.V., Morstel, Belgium) software. Patients' characteristics and clinical outcomes were evaluated between patients with and without thrombus formation. Results: During the study period, we detected a new postoperative in-stent thrombus in 19 patients (6%). These patients were significantly older (p = 0.009), predominantly female (p = 0.002) and were more commonly treated for aortic aneurysms (p = 0.001). In 15 patients (79%), the thrombi were located in the distal half of the FET stent-graft. Thrombus size was 18.9 mm (first quartile: 12.1; third quartile: 33.2). Distal embolisation occurred in 4 patients (21%) causing one in-hospital death caused by severe visceral ischaemia. Therapeutic anticoagulation was initiated in all patients. Overstenting with a conventional stent-graft placed within the FET stent-graft was the treatment in 2 patients (11%). Outcomes were comparable both groups. Female sex (p = 0.005; OR: 4.289) and an aortic aneurysm (p = 0.023; OR: 5.198) were identified as significant predictors for thrombus development. Conclusion: Postoperative new thrombus formation within the FET stent-graft is a new, rare, but clinically highly relevant event. The embolisation of these thrombi can result in dismal postoperative outcomes. More research is therefore required to better identify patients at risk and improve perioperative treatment.