Prevention versus cure: Is BioGlue priming the optimal strategy against E-Vita NEO graft oozing?

BACKGROUND: Since the introduction of the E-Vita Open NEO aortic prosthesis in 2020, several incidences of post-anastomotic oozing from the polyester portion of the graft have emerged. The use of BioGlue to prime E-Vita Open NEO to prevent this has been suggested as a way to mitigate this worrying complication. We investigate the extent of graft oozing in E-Vita Open NEO and evaluate the use of BioGlue in preventing oozing, both experimentally and in terms of potential clinical complications. MATERIALS AND METHODS: E-Vita Open NEO (in straight and branched configurations) was implanted in a perfused model. The distal stent graft and side branches were clamped, and the graft was pressurized with blood to 120 mmHg. The volume of blood (ml) oozing from the graft within 60 s was measured. Nonpressurized grafts were coated with BioGlue up to a thickness of 1, 2, and 3 mm, and the volume (mm3 ) of BioGlue required to do so was recorded. RESULTS: Within 60 s, 250.0 ml of blood oozed from the grafts tested. 43.694, 87.389, and 174.778 mm3 of BioGlue were required to coat the device with 1, 2, and 3 mm of BioGlue. CONCLUSION: Graft oozing from E-Vita Open NEO represents an omnipresent and worrying risk. The use of BioGlue herein is likely associated with several adverse consequences, which are an additional risk on top of that posed by graft oozing. These risks call into question the suitability of E-Vita Open NEO, especially when compared to alternative devices not affected by oozing.

Aortic valve neocuspidization using autologous versus bovine pericardium: Ozaki versus Batista.

BACKGROUND: The average living age of the population is constantly increasing and so is the incidence and prevalence of aortic valve disease. Surgical aortic valve replacement (SAVR) is the current gold standard treatment. Nevertheless, the use of prosthetic valves in SAVR is associated with issues that impact patients' quality of life. Aortic valve neocuspidization (AV Neo) offers a means to solve this dilemma by minimizing foreign valve tissue. AV Neo can either be performed using glutaraldehyde-treated autologous pericardium (Ozaki procedure) or bovine pericardium (Batista procedure). AIMS: This commentary aims to discuss the recent study by Chan and colleagues which highlighted the surgical approach, clinical outcomes, and limitations of the Ozaki procedure, and compare this to the Batista procedure. METHODS: A comprehensive literature search was performed using multiple electronic databases including PubMed, Ovid, Embase, and Scopus to collate the relevant research evidence. RESULTS: Although the Ozaki procedure can achieve favorable results whilst mainly avoiding the need for life-long oral anticoagulation with mechanical valves, it still has several limitations that may hinder results. AV Neo using glutaraldehyde-treated bovine pericardium, developed by pioneer cardiac surgeon Dr. Randas J. Vilela Batista, yields superior clinical outcomes to Ozaki's, including excellent survival, lower complications, and minimal need for reoperation as well as shorter operative times. CONCLUSION: AV Neo offers a means to perform SAVR whilst escaping the prosthetic valve issues. However, the Batista procedure has shown beyond doubt that it can be considered the superior approach for AV Neo over the Ozaki procedure.

Monocyte to high-density lipoprotein ratio as a predictive biomarker for in-hospital mortality following surgery for type A aortic dissection: Reality or myth?

BACKGROUND: Type A aortic dissection (TAAD) is a life-threatening clinical emergency requiring timely surgical intervention. If untreated, 50% of TAAD die within the first 24 h, with mortality increasing by 1%-2% every passing hour within the first 48 h of presentation. Surgical repair of TAAD is a major procedure associated with relatively high mortality and morbidity postoperatively. Several inflammatory biomarker have been linked to aortic dissection (AD) as diagnostic and/or prognostic tools, one example is the monocyte count to high-density lipoprotein ratio (MHR). AIMS: This commentary aims to discuss the recent study by Savas et al. which investigated the use of MHR as a predictive biomarker for in-hospital mortality following surgery for TAAD. METHODS: We carried out a literature search on multiple electronic databases including PUBMED and Scopus to collate research evidence to assess the value of MHR as a prognostic biomarker in AD. RESULTS: Savas et al. proved that MHR is an effective predictive biomarker for in-hospital mortality following surgical repair of TAAD by demonstrating that MHR was independently associated with in-hospital mortality in this subset of patients. CONCLUSION: Despite the advancement in surgical and perfusion techniques, surgical management of TAAD remains associated with relatively high risk of mortality and morbidity. Using prognostic biomarkers such as MHR can provide a means of reducing in-hospital mortality by identifying those at risk. Yet, further research into this area is encouraged.

Risk profile analysis of uncomplicated type B aortic dissection patients undergoing thoracic endovascular aortic repair: Laboratory and radiographic predictors.

BACKGROUND: There is emerging evidence to support pre-emptive thoracic endovascular aortic repair (TEVAR) intervention for uncomplicated type B aortic dissection (unTBAD). Pre-emptive intervention would be particularly beneficial in patients that have a higher baseline risk of progressing to complicated TBAD (coTBAD). There remain debate on the optimal clinical, laboratory, morphological, and radiological parameters, which would identify the highest-risk patients that would benefit most from pre-emptive TEVAR. AIM: This review summarizes evidence on the clinical, laboratory, and morphological parameters that increase the risk profiles of unTBAD patients. METHODS: A comprehensive literature search was carried out on multiple electronic databases including PubMed, EMBASE, Ovid, and Scopus to collate all research evidence on the clinical, laboratory, and morphological parameters that increase the risk profiles of unTBAD patients RESULTS: At present, there are no clear clinical guidelines using risk-stratification to inform the selection of unTBAD patients for TEVAR. However, there are noticeable literature trends that can assist with the identification of the most at-risk unTBAD patients. Patients are at particular risk when they have refractory pain and/or hypertension, elevated C-reactive protein (CRP), larger aortic diameter, and larger entry tears. These risks should be considered alongside factors that increase the procedural risk of TEVAR to create a well-balanced approach. Advances in biomarkers and imaging are likely to identify more pertinent parameters in the future to optimize the development of balanced, risk-stratified treatment protocols. CONCLUSION: There are a variety of risk profiling parameters that can be used to identify the high-risk unTBAD patient, with novel biomarkers and imaging parameters emerging. Longer-term evidence verifying these parameters would be ideal. Further randomized controlled trials and multicentre registry analyses are also warranted to guide risk-stratified selection protocols.

Coronary artery involvement in type A aortic dissection: Fate of the coronaries.

BACKGROUND: Type A aortic dissection (TAAD) involves a tear in the intimal layer of the thoracic aorta proximal to the left subclavian artery, and hence, carries a high risk of mortality and morbidity and requires urgent intervention. This dissection can extend into the main coronary arteries. Coronary artery involvement in TAAD can either be due to retrograde extension of the dissection flap into the coronaries or compression and/or blockage of these vessels by the dissection flap, possibly causing myocardial ischemia. Due to the emergent nature of TAAD, coronary involvement is often missed during diagnosis, thereby delaying the required intervention. AIMS: The main scope of this review is to summarize the literature on the incidence, mechanism, diagnosis, and treatment of coronary artery involvement in TAAD. METHODS: A comprehensive literature search was performed using multiple electronic databases, including PubMed, Ovid, Scopus and Embase, to identify and extract relevant studies. RESULTS: Incidence of coronary artery involvement in TAAD was seldom reported in the literature, however, some studies have described patients diagnosed either preoperatively, intraoperatively following aortic clamping, or even during autopsy. Among the few studies that reported on this matter, the treatment choice for coronary involvement in TAAD was varied, with the majority revascularizing the coronary arteries using coronary artery bypass grafting or direct local repair of the vessels. It is well-established that coronary artery involvement in TAAD adds to the already high mortality and morbidity associated with this disease. Lastly, the right main coronary artery was often more implicated than the left. CONCLUSION: This review reiterates the significance of an accurate diagnosis and timely and effective interventions to improve prognosis. Finally, further large cohort studies and longer trials are needed to reach a definitive consensus on the best approach for coronary involvement in TAAD.

Favorable neurological outcomes in thoracic endovascular aortic repair with RELAY™ branched-An international perspective.

BACKGROUND: While open surgical repair continues to be the mainstay option for aortic arch reconstruction, the associated mortality, morbidity, and high turn-down rates have led to a need for the development of minimally invasive options for aortic arch repair. Though RELAY™ Branched (Terumo Aortic, Inchinnan, UK) represents a promising option for complex endovascular aortic arch repair, neurological complications remain a pertinent risk. Herein we seek to present multicenter data from Europe documenting the neurological outcomes associated with RELAY™ Branched. METHODS: Prospective data collected between January 2019 and January 2022 associated with patients treated with RELAY™ single-, double-, and triple-branched endoprostheses from centers across Europe was retrospectively analyzed with descriptive and distributive analysis. Follow-up data from 30 days and 6, 12, and 24 months postoperatively were included. Patient follow-up was evaluated for the onset of disabling stroke (DS) and non-disabling stroke (NDS). RESULTS: Technical success was achieved in 147 (99.3%) cases. Over 24 months period, in total, six (4.1%) patients suffered DS, and eight (5.4%) patients suffered NDS after undergoing aortic arch repair with RELAY™. All patients that developed postoperative DS had been treated with the double-branched RELAY™ endoprosthesis. DISCUSSION: The data presented herein demonstrates that RELAY™ Branched is associated with favorable neurological outcomes and excellent technical success rates. Key design features of the endoprosthesis and good perioperative management can contribute greatly to mitigating neurological complications following endovascular aortic arch repair.

What is the optimal timing for thoracic endovascular aortic repair in uncomplicated Type B aortic dissection?

BACKGROUND: Uncomplicated Stanford Type B aortic dissection (un-TBAD) is characterized by a tear in the aorta distal to the left subclavian artery without ascending aorta and arch involvement. Optimized cardiovascular control (blood pressure and heart rate) is the current gold standard treatment according to current international guidelines. However, emerging evidence indicates that thoracic endovascular aortic repair (TEVAR) is both safe and effective in the treatment of un-TBAD with improved long-term survival outcomes in combination with optimal medical therapy (OMT) relative to OMT alone. However, the optimal timeframe for intervention is not entirely clarified. AIMS: This review critically addresses current state-of-the-art comparing TEVAR with OMT and corresponding clinical outcomes for un-TBAD based on timing of intervention. METHODS: We carried out a comprehensive literature search on multiple electronic databases including PUBMED and Scopus to collate all research evidence on timing of TEVAR in uncomplicated Type B aortic dissection. RESULTS: TEVAR has proven to be a safe and effective treatment for un-TBAD in combination with OMT through comparable survival outcomes, improved aortic remodeling, and relatively low periprocedural added risks. Though the timing of intervention remains controversial, it is becoming clear that performing TEVAR during the subacute phase of un-TBAD yields better outcomes compared to earlier and delayed (>90 days) intervention. CONCLUSIONS: Further research is required into both short- and long-term outcomes of TEVAR in addition to its optimal therapeutic window for un-TBAD. With stronger evidence, TEVAR is likely to be adopted as the gold-standard intervention for un-TBAD with definitive timeframe guidelines.

The misnomer of uncomplicated type B aortic dissection.

BACKGROUND: Acute type B aortic dissection (TBAD) is a rare condition that can be divided into complicated (CoTBAD) and uncomplicated (UnCoTBAD) based on certain presenting clinical and radiological features, with UnCoTBAD constituting the majority of TBAD cases. The classification of TBAD directly affects the treatment pathway taken, however, there remains confusion as to exactly what differentiates complicated from uncomplicated TBAD. AIMS: The scope of this review is to delineate the literature defining the intervention parameters for UnCoTBAD. METHODS: A comprehensive literature search was conducted using multiple electronic databases including PubMed, Scopus, and EMBASE to collate and summarize all research evidence on intervention parameters and protocols for UnCoTBAD. RESULTS: A TBAD without evidence of malperfusion or rupture might be classified as uncomplicated but there remains a subgroup who might exhibit high-risk features. Two clinical features representative of "high risk" are refractory pain and persistent hypertension. First-line treatment for CoTBAD is TEVAR, and whilst this has also proven its safety and effectiveness in UnCoTBAD, it is still being managed conservatively. However, TBAD is a dynamic pathology and a significant proportion of UnCoTBADs can progress to become complicated, thus necessitating more complex intervention. While the "high-risk" UnCoTBAD do benefit the most from TEVAR, yet, the defining parameters are still debatable as this benefit can be extended to a wider UnCoTBAD population. CONCLUSION: Uncomplicated TBAD remains a misnomer as it is frequently representative of a complex ongoing disease process requiring very close monitoring in a critical care setting. A clear diagnostic pathway may improve decision making following a diagnosis of UnCoTBAD. Choice of treatment still predominantly depends on when an equilibrium might be reached where the risks of TEVAR outweigh the natural history of the dissection in both the short- and long-term.

Criteria for endovascular intervention in type B aortic dissection.

BACKGROUND: The use of thoracic endovascular aortic repair (TEVAR) for the management of uncomplicated type B aortic dissection (un-TBAD) remains controversial. There is a lack of consensus over whether pre-emptive TEVAR should be carried out in patients with un-TBAD at risk of progression to complicated TBAD. We present a review of current evidence and seek to suggest criteria where endovascular intervention in un-TBAD may prove beneficial relative to pharmacotherapy alone. METHODS AND MATERIALS: PubMed and Cochrane databases were searched using terms including: type B aortic dissection, risk factors, medical therapy, TEVAR, false lumen (FL) expansion, and mortality. Papers were selected based on title and abstract. RESULTS: Optimal medical therapy remains the mainstay treatment for patients with un-TBAD, however, patients with un-TBAD present with varying degrees of disease progression risk. Factors such as age, aortic morphology, history of connective tissue disorders, FL thrombosis, and aortic branch involvement may potentiate progression from un-TBAD to complicated TBAD. Short- and long-term outcomes associated with TEVAR for TBAD remain promising. CONCLUSION: Pre-emptive TEVAR may be beneficial in patients with un-TBAD presenting with the above factors, however, further prospective research into the optimal timing for TEVAR in un-TBAD is required.

Mid- and long-term outcomes of thoracic endovascular aortic repair in acute and subacute uncomplicated type B aortic dissection.

BACKGROUND: Uncomplicated type B aortic dissection (un-TBAD) has been managed conservatively with medical therapy to control the heart rate and blood pressure to limit disease progression, in addition to radiological follow-up. However, several trials and observational studies have investigated the use of thoracic endovascular aortic repair (TEVAR) in un-TBAD and suggested that TEVAR provides a survival benefit over medical therapy. Outcomes of TEVAR have also been linked with the timing of intervention. AIMS: The scope of this review is to collate and summarize all the evidence in the literature on the mid- and long-term outcomes of TEVAR in un-TBAD, confirming its superiority. We also aimed to investigate the relationship between the timing of TEVAR intervention and results. METHODS: We carried out a comprehensive literature search on multiple electronic databases including PubMed, Scopus, and EMBASE to collate and summarize all research evidence on the mid- and long-term outcomes of TEVAR in un-TBAD, as well as its relationship with intervention timing. RESULTS: TEVAR has proven to be a safe and effective tool in un-TBAD, offering superior mid- and long-term outcomes including all-cause and aorta-related mortality, aortic-specific adverse events, aortic remodeling, and need for reintervention. Additionally, performing TEVAR during the subacute phase of dissection seems to yield optimal results. CONCLUSION: The evidence demonstrating a survival advantage in favor TEVAR over medical therapy in un-TBAD means that with further research, particular trials and observational studies, TEVAR could become the gold-standard treatment option for un-TBAD patients.

Uniformity in bioprosthetic mitral valve sizing-When will we get there?

Much has changed since the introduction of surgical valve repair in the 1950s, from the introduction bioprosthetic valves to percutaneous approaches to valve repair. Yet, despite substantial advancements in bioprosthetic valve technology, there has been a lack of direct, independent comparison between bioprosthetic mitral valve devices, accompanied by a marked heterogeneity in approaches to the sizing and selection thereof. Wang et al. have hence endeavored to evaluate, head-to-head, the technical successes and biomechanical outcomes associated with three different bioprosthetic mitral valves (Epic; Abbott; Mosaic; Medtronic; Mitris Resilia; Edwards Lifesciences) in a porcine model, under standardized hemodynamic and anatomical conditions. With a robust experimental technique, they have made clear the heterogeneity in both sizing and biomechanical properties between bioprosthetic mitral valves, and have further emphasized the need for a uniform approach to the manufacturing and sizing of bioprosthetic valves.

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

BACKGROUND: The use of the Frozen Elephant Trunk (FET) device to manage complex surgical pathologies of the aorta (such as acute type A aortic dissection) has gained popularity since its introduction in the early 2000s. Though the distal anastomosis was traditionally performed at aortic Zone 3 (Z-3-FET), preference gradually shifted towards Zone 2 (Z-2-FET) in favor of improved surgical access and clinical outcomes. This review seeks to elucidate whether proximalization of arch repair to Zone 0 (Z-0-FET) would further improve postoperative outcomes. METHODS: We performed a review of available literature to evaluate the comparative efficacies of Z-2-FET versus Z-0-FET, in terms of surgical technique, clinical outcomes, and incidence of adverse events. RESULTS: Z-0-FET seems to be associated with a more accessible surgical approach, and shorter cardiopulmonary bypass, antegrade cerebral perfusion, and cardioplegia durations than Z-2-FET. Further, Z-0-FET is could potentially be associated with a lower incidence of neurological, renal, and recurrent laryngeal nerve injury, as well as mortality and reintervention rates than Z-2-FET. This said, Z-0-FET is itself associated with significant challenges, and efficacy in terms of postoperative true lumen integrity and false lumen thrombosis is mixed. CONCLUSION: Current literature seems to suggest that Z-0-FET procedures are more straightforward and associated with lower rates of certain adverse events, however, the majority of data reviewed is retrospective. This review, therefore, recommends prospective research into the comparative strengths and limitations of Z-0-FET and Z-2-FET to better substantiate whether proximalization of arch repair represents a concept, or a true challenge to advance surgical intervention for arch pathologies.

Patient longevity and survival with custom-made endovascular solutions: The Fenestrated AnacondaTM approach.

BACKGROUND: Endovascular aortic repair (EVAR) has become the mainstay treatment for abdominal aortic aneurysms and is associated with excellent clinical outcomes. However, there remains a risk of complications requiring reintervention. Several EVAR devices exist commercially, yet, the Terumo Aortic Fenestrated Anaconda™ has demonstrated outstanding results. The main scope of this study is to evaluate survival/longevity, target vessel patency (TVP), endograft migration and reintervention following Fenestrated Anaconda™ implantation and discuss relevant literature. METHODS: The current study represents a 9-year cross-sectional international analysis of custom-made Fenestrated Anaconda™ device. For the statistical analysis, SPSS 28 for Windows and R was utilised. Pearson Chi-Square analysis was used to assess differences in cumulative distribution frequencies between variables. Statistical significance for all two-tailed tests was set at p < 0.05. RESULTS: A total of 5058 patients received the Fenestrated Anaconda™ endograft. The Fenestrated Anaconda™ was indicated either due to complex anatomy for competitor devices (n = 3891, 76.9%) or based on surgeon preference (n = 1167, 23.1%). Both survival and TVP were 100% during the first 6 postoperative years but dropped to 77.1% and 81% thereafter. In the complex anatomy indication group, cumulative survival and TVP were both 100% until year 7 post-EVAR when they decreased to 82.8% and 75.7%. In the other indication group, survival and TVP were also 100% during the first 6 years but plateaued at 58.1% and 98.8% in years 7-9 of follow-up. No cases of endograft migration and reintervention were recorded. CONCLUSION: The Fenestrated Anaconda™ has been proven across the literature to be a highly effective EVAR endograft, as it has demonstrated excellent survival/longevity and TVP as well as minimal endograft migration and reintervention.

Can the Fenestrated Anaconda™ salvage failed competitor endografts? An international frame of reference.

INTRODUCTION: An abdominal aortic aneurysm (AAA) is a life-threatening abnormal dilation of the abdominal aorta that can be repaired either endovascularly or with open surgery. However, endovascular aortic repair (EVAR) has become the main treatment modality for AAA due to its more optimal results. EVAR devices can either be standard, fenestrated, or branched, with fenestrated EVAR (FEVAR) seemingly achieving superior prospects. Although EVAR is associated with excellent outcomes, it still carries a risk of certain complications requiring reintervention or 'rescue'. Several commercial EVAR devices are available on the global market, nevertheless, the Fenestrated Anaconda developed by Terumo Aortic can be considered the superior device due to the wide range of endovascular solutions that it offers along with its unique custom-made approach, excellent results and its highly promising potential to be used as a 'rescue' device for failed competitor endografts. MATERIALS AND METHODS: The current study represents a 9-year cross-sectional international analysis of a custom-made Fenestrated Anaconda™ device. For the statistical analysis, SPSS 28 for Windows and R were utilised. Pearson Chi-square analysis was used to assess differences in cumulative distribution frequencies between select variables. Statistical significance for all two-tailed tests was set at p < 0.05. RESULTS: Out of 5058 EVARs performed using the Fenestrated Anaconda, 2987 (59%) were 'rescue' procedures for migrated Gore (n = 252) and Medtronic (n = 2735) devices. The Fenestrated Anaconda™ was indicated as the reintervention device either due to unsuitable/complex anatomy for the competitor (n = 2411) or based on surgeon preference (n = 576). Overall, the Fenestrated Anaconda was utilised to rescue 3466 (68.5%) failed previous EVARs using competitor devices. Yet, the primary endovascular solution offered by the Fenestrated Anaconda was FEVAR (91.3%), with 112 (2.2%) devices using custom-made iliac stents. DISCUSSION: The use of the Fenestrated Anaconda endograft as a 'rescue' device to salvage failed competitor devices is well-established in the literature with excellent clinical outcomes achieved. The evidence in the literature also highlights the distinctive custom-made approach that the Fenestrated Anaconda offers which enables it to treat extremely complex aortic anatomy.

Frozen Elephant Trunk Sizing: A 30,000-Feet Perspective with Thoraflex Hybrid Stent Graft.

There is currently no standard, evidence-based approach for sizing the Thoraflex Hybrid prosthesis in frozen elephant trunk surgery. We present regional data on 906 Thoraflex grafts implanted in the United Kingdom between December 2012 and August 2021 to emphasize the heterogeneity in sizing practices and evaluate the impact this may have on clinical outcomes. Highlighting this heterogeneity will help develop an evidence-based approach to prosthesis sizing, thereby aiding decision-making for arch repair.

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.

Institutional practice in sizing of the hybrid prosthesis in frozen elephant trunk surgery.

BACKGROUND: The frozen elephant trunk (FET) technique for total arch replacement (TAR) is widely used for repair of aortic arch dissections and aneurysms. Despite its widespread adoption, there are no international or regional guidelines for the sizing of FET prostheses in TAR. We seek to highlight the heterogeneity thereof and pave the way for evidence-based guidelines to advise FET prosthesis sizing in TAR. METHODS: An online questionnaire was sent to 22 specialist aortic surgeons from 13 different countries across North America, Europe, Asia, and Australia, inquiring about each surgeon's approach to FET prosthesis sizing. The results were then pooled for frequency analysis. RESULTS: All 22 surgeons responded to the questionnaire. Zone 2 is preferred implantation zone for AAD, CAD, and TAA (selected by 72.7%, 72.7%, and 68.2% respectively). The maximal diameter of the true lumen in the DTA is the most common index measurement for AAD and CAD (40.9% and 59.1%, respectively). Stent-graft diameters equal to the index measurement is the most common approach for AAD and CAD (77.3% and 45.5%, respectively) while 59.1% of surgeons oversize the index diameter by 10% for TAA; 100 mm is the preferred length for 50.0%, 27.3%, and 40.9% of surgeons in AAD, CAD, and TAA respectively. CONCLUSIONS: There is considerable heterogeneity in sizing practices for FET prostheses internationally, with variable evidence for its impact on clinical outcomes. This issue would be aided by the development of evidence-based guidelines to inform clinical decision making.