Elephant Trunk Procedure Research Articles

Hybrid total arch replacement via ministernotomy for Stanford type A aortic dissection.

Type A aortic dissection (TAAD) is a cardiovascular emergency condition with high mortality rate. Hybrid total aortic arch replacement using endovascular graft for the descending aorta repair results in favorable outcomes and has been recommended as an alternative procedure for the higher-risk category patients. Our institution started applying the upper ministernotomy incision technique for the hybrid procedures back in 2018. We collected patients who underwent hybrid total arch replacement (HTAR) via ministernotomy (96) and total arch replacement with frozen elephant trunk (TAR + FET) procedures (99), between 2018 and 2021. The baseline information, intraoperative and postoperative characteristics have been compared. Kaplan-Meier analysis was used for survival evaluation. Cox regression were applied to identify the independent predictor of mortality. The baseline characteristics between the two patient groups were compared and found similar, except that RBC counts were higher (p = 0.038) and the ascending aorta diameter was smaller (P = 0.019) in the "HTAR" group relative to the "TAR + FET" group. The cardiopulmonary bypass time (P < 0.001), the aortic cross clamp time (P < 0.001), the operation duration (P = .029), ICU (P = 0.037) and postoperative hospital stay (P = 0.002) were shorter in the "HTAR" group. The "HTAR" group exhibited also significantly lower levels of intraoperative transfusion (all <0.001) characteristics than the "TAR + FET" group. The hospital mortality and 1-year mortality revealed similar patterns in both groups. HTAR via ministernotomy have similar short term prognosis, and also reduced the ICU and postoperative hospital stay. In all, The application of the ministernotomy technique in HTAR was safe and technically feasible and may benefit individual patients as well as hospitals in general.

Spinal cord injury after frozen elephant trunk procedures—prevention and management.

Spinal cord injury after frozen elephant trunk procedures—prevention and management.

The Frozen Elephant Trunk Procedure Using New Russian Hybrid Prosthesis "Soft Elephant Trunk": the Early Experience.

Aim To present the first experience of performing the Frozen Elephant Trunk (FET) surgery in patients with thoracic aorta disease using a new Russian hybrid stent graft "Soft Elephant Trunk".Material and methods Between 2014 and 2021, 170 patients with thoracic aortic disease underwent complete aortic arch replacement using the FET technique. In 70 of these cases (since June 2019), a hybrid graft "Soft Elephant Trunk" was used. A specific feature of this graft is the conical reduction of the radial force of nitinol crowns and the soft distal end without radial force. The study endpoints were early postoperative results, as well as the absence of reoperations on the aorta, absence of stent-graft-associated complications, including distal stent-graft-induced fenestration, and survival at a mid-term follow-up of up to 2.5 years.Results Interventions were performed in patients with A type aortic dissection (n=51; 72.9 %), type B aortic dissection (n=13; 18.6 %), and thoracoabdominal aortic aneurysm (TAAA) (n=6; 8.5 %). In 14 (20 %) of these cases, interventions were performed after a primary intervention on the proximal aorta. Acute aortic dissection was diagnosed in 17 (24.3 %) cases. Aortic root replacement was performed in 21 (30 %) cases, David procedure in 5 (7.2 %) cases, Bentall-DeBono procedure in 11 (15.7 %) cases, and supracoronary graft placement in 33 (47.1 %) cases. There were no cases of paraplegia or paraparesis. Respiratory insufficiency was observed in 8 (11.4%) cases. In one (1.4%) case, acute renal failure developed, which required renal replacement therapy. In-hospital mortality was 4.3 % (3 patients died). Mean follow-up duration was 9 [4.25; 16] months. Three-year survival was 94 % (95 % confidence interval, CI: 88-99.9) and absence of reoperation was 96.6 % (95 % CI: 90.1-100). There were no cases of distal stent-graft-induced fenestration in this group.Conclusion The new hybrid graft, due to its specific structure, provides prevention of distal stent-graft-induced fenestration and, thereby, a stable long-term result. Using this stent-graft is effective in patients with thoracic aorta pathology undergoing the FET surgery. However, further studies are needed to determine potential advantages and disadvantages of this new hybrid graft, to obtain long-term results and accumulate experience.

Open surgical treatment for aortic arch and coronary artery aneurysms associated with immunoglobulin G4-related disease: a case report

BackgroundImmunoglobulin G4-related disease (IgG4RD) is a systemic autoimmune disease characterized by a dense lymphoplasmacytic infiltrate containing IgG4-positive plasma cells that can cause aneurysms in various organs and tissues. There have been many reports of IgG4RD aneurysms; however, the surgical procedures adopted remain controversial. Herein, we report a case in which surgical treatment for IgG4-related aneurysms was successful.Case presentationAn 83-year-old woman with IgG4-related disease developed multiple aneurysms, including thoracic aortic aneurysm (TAA), right coronary artery aneurysm (CAA), abdominal aortic aneurysm, and common iliac artery aneurysm. Enhanced computed tomography (CT) revealed progressive enlargement of the TAA, while positron emission tomography-CT revealed intense 18F-fluorodeoxyglucose uptake around the TAA and CAA, suggesting the presence of adhesive tissue caused by adventitial inflammation around the aneurysms. Open aortic arch replacement with frozen elephant trunk procedure and coronary artery bypass grafting with ligation of the coronary artery were performed to treat the TAA and CAA. No surgical complications occurred. The postoperative CT scan showed no endoleak around the open stent graft and the coronary artery was patent. The patient is being followed up on an outpatient basis after discontinuing steroid therapy.ConclusionsWe report the successful surgical treatment of IgG4-related multiple aneurysms. Our findings reveal that the main site of inflammation in aneurysms of IgG4RD is the adventitia and the frozen elephant trunk procedure is useful for avoiding complications.

Distal stent graft – induced new entry after frozen elephant trunk procedure for type a aortic dissection: two cases report

Objectives: We report two clinical cases that wherein stent graft-induced new entry (dSINE) after frozen elephant trunk (FET) procedure for type A aortic dissection were resolved successfully by additional stent graft placement.&#x0D; Methods: Describe rare clinical cases.&#x0D; Results: Two patients were hospitalized after FET procedure for type A aortic dissection treatment. The former had refractory abdominal pain and the latter had sudden chest pain; both their abdominal thoracic CT scanner showed dSINE. We decided to place additional stent grafts to cover the new entry. Both patients recovered well and were discharged after 5 and 12 days, respectively, without any significant complications.&#x0D; Conclusions: Supplemental stent graft placement is an effective and safe treatment choice for dSINE post-FET procedure.

Early results of frozen elephant trunk in acute type-A dissection in 1445 patients

BackgroundWe aimed to briefly describe the use of total arch replacement with frozen elephant trunk in our center's 12-year treatment of acute type A dissection and the early postoperative results. We summarized the practical experience of this procedure in our center and performed regression analyses to find the independent risk factors for major complications. MethodsConsecutive patients with acute type A dissection having surgical total arch replacement with the implantation of a frozen elephant trunk were collected from January 2010 to December 2021 and were included in the analysis. For each major operation-related complication, independent risk factors were identified using both univariate and multivariate regression models. ResultsIn our institution, the total arch replacement with frozen elephant trunk procedure is used more frequently each year and makes up 70% of the surgical procedures for acute type A dissection. The overall postoperative mortality rate was 6.2%, which declined as the techniques (including surgical procedures, organ perfusion protection etc.) improved. Other complications include: 11.7% for continuous renal replacement therapy, 5.7% for stroke, 17.8% for ICU stay longer than 7 days, 10.9% for prolonged mechanical ventilation, and so on. According to regression analysis, different major complications had different independent risk factors. Several factors, such as advanced age, impaired renal function, and extended cardiopulmonary bypass time, were found to be implicated in nearly all of the complications. ConclusionTotal arch replacement plus frozen elephant trunk strategy is a safe surgical method for extensive acute type A dissection. Some factors, such as advanced age, impaired renal function, and prolonged cardiopulmonary bypass time, might be associated with poor prognosis.

Five-Year Outcomes of Hybrid Arch Frozen Elephant Trunk Repair With Novel Multibranched Hybrid Graft

BackgroundThe objective of this study was to report the 5-year outcomes of hybrid arch frozen elephant trunk (FET) procedures with a multibranched hybrid graft. MethodsBetween 2014 and 2020, 50 consecutive patients (63 ± 15 years old; 34% women) underwent hybrid arch FET with Thoraflex hybrid graft (Terumo Aortic) at a single center. Indications included aortic aneurysm (n = 48 [96%]), acute aortic dissection (n = 10 [20%]), and chronic dissection (n = 20 [40%]). Follow-up was complete, and mean follow-up was 1455 ± 664 days. ResultsAll 50 patients experienced successful device implantation. The 30-day/in-hospital mortality was 2% (n = 1). Stroke and transient neurologic deficits occurred in 1 patient (2%) and 3 patients (6%). Two patients (4%) and 1 patient (2%) experienced transient and permanent spinal cord ischemia. FET thromboembolic complication was observed in 1 patient (2%). In follow-up, 6 patients died of aortic events, and there were 13 reinterventions in the downstream aorta, of which 46% (6/13) were planned second-stage operations. Survival rate at 1 year, 2 years, and 5 years was 96%, 92%, and 85%, and freedom from unplanned distal reintervention at 1 year, 2 years, and 5 years was 98%, 92%, and 81%. Computed tomography follow-up demonstrated positive distal aortic remodeling with aneurysmal regression and stabilized aortic dimensions in patients with aortic dissection. ConclusionsThe hybrid arch FET procedure with a novel hybrid graft is associated with good early and midterm outcomes. Longer term outcomes merit further investigation.

Thoracoscopic Clipping of Intercostal Artery for Treatment of Type II Endoleak Following Frozen Elephant Trunk Procedure: Case Report.

A 38-year-old man with history of Crawford extent I thoracoabdominal aneurysm and chronic type B1,10 aortic dissection underwent a hybrid repair using the frozen elephant trunk technique. The patient was followed up annually, and type II endoleak of the descending thoracic aorta was diagnosed, leading to negative aortic remodeling. The endoleak was managed by performing intercostal artery clipping using minimally invasive thoracoscopic technique under transesophageal echocardiography control. The computed tomography scan showed no endoleak and complete false-lumen thrombosis with positive remodeling in the distal aortic segments.

Discussion to: False lumen-dependent segmental arteries are associated with spinal cord injury in frozen elephant trunk procedure for acute type I aortic dissection

Discussion to: False lumen-dependent segmental arteries are associated with spinal cord injury in frozen elephant trunk procedure for acute type I aortic dissection

False lumen–dependent segmental arteries are associated with spinal cord injury in frozen elephant trunk procedure for acute type I aortic dissection

ObjectiveTo investigate the association between false lumen (FL) dependency of segmental arteries (SAs) at T9-L3 levels and the risk of spinal cord injury (SCI) following total arch replacement and frozen elephant trunk (FET) implantation in the setting of acute DeBakey type I aortic dissection (AAD). MethodsThe study involved consecutive patients with AAD who underwent total arch replacement and FET implantation between 2020 and 2022. Primary outcome was postoperative SCI. The inverse probability of treatment weighting (IPTW) method was employed to minimize the impact of no-randomization bias. Antegrade placement of FET was followed by end-to-end anastomosis of a 4-branch arch graft at the proximal landing site of FET. ResultsA total of 146 patients were included (age, 50.5 ± 11.7 years, 115 male), of whom 35 (24%) had SAs at T9-L3 levels completely dependent on FL (FL-dependency group). There was no significant difference in early (30-day or in-hospital) mortality rates between FL-dependency (14.3%) and FL-independency (18.0%) groups (P = .80), however, the rate of SCI was significantly higher in the FL-Dependency group (34.3% vs 2.7%, P < .001). After adjustments, FL dependency was associated with a significantly increased risk of SCI (odds ratio, 13.1; 95% confidence interval, 4.2-41.0; P < .001), whereas it was not significantly associated with risks of early mortality or other major complications (P = .16-.98). ConclusionsFL dependency of SAs at the T9-L3 levels was significantly associated with the development of SCI following FET implantation in AAD, warning against its uses on patients presenting with FL dependency of SAs at critical segments.

Long-Term Results with 187 Frozen Elephant Trunk Procedures.

The frozen elephant trunk (FET) technique is an established therapeutic option in the treatment of complex aortic diseases. We report our long-term clinical outcomes after FET repair. A total of 187 consecutive patients underwent FET repair at our department between 8/2005 and 3/2023. Indications included acute and chronic aortic dissections and thoracic aneurysms. Endpoints included operative morbidity and mortality, long-term survival, and the need for reinterventions. Operative mortality, spinal cord injury and permanent stroke rates were: 9.6%, 2.7% and 10.2%, respectively. At five years, overall survival was 69.9 ± 3.9% and freedom from aortic-related death was 82.5 ± 3.0%, whereas at ten years, overall survival was 53.0 ± 5.5% and freedom from aortic-related death was 75.8 ± 4.8%. Sixty-one reinterventions on the thoracic aorta were necessary. Freedom from secondary interventions at ten years was 44.7 ± 6.4% overall (63.1 ± 10.0% for acute dissections, 40.8 ± 10.3% for chronic dissections and 28.9 ± 13.1% for aneurysms, respectively). The high reintervention rate for chronic dissections and for aneurysms is related to the pre-existing aortic pathology. Late aortic growth of untreated segments with potentially fatal outcome occurs even after ten years, so careful annual follow-up is mandatory in this patient cohort.

Fracture and embolization of a metal stent after a frozen elephant trunk procedure.

The Frozenix J graft open stent graft has been available since 2014 in Japan. This stent is widely used for the frozen elephant trunk technique in many institutions, mainly for cases of acute type A aortic dissection and also for cases of a true aneurysm and chronic aortic dissection. We treated a rare case in which the metal wires of the Frozenix J graft were broken and embolized to the periphery half a year after being implanted.

The Arch-First Technique for Complex Arch and Proximal Descending Aortic Aneurysms

Aneurysms involving both the aortic arch and proximal descending aorta present a unique surgical challenge due to their anatomical location, with neither standard sternotomy nor thoracotomy alone providing adequate exposure to complete a full repair. Conventional and frozen elephant trunk procedures have inherent problems, including high cumulative mortality and high spinal cord ischaemia rates, which may be obviated using a single-stage technique via bilateral thoracotomies or extended median sternotomy with left anterior thoracotomy.

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

The purpose of this study was to evaluate the risk factors of distal stent graft-induced new entry (dSINE) after frozen elephant trunk (FET) procedure for aortic dissection (AD) and to consider strategies to prevent this complication. This retrospective review included 52 patients who had undergone aortic arch repair for AD with the FET procedure using J Graft FROZENIX from 2014 to 2020 at a single center. Baseline characteristics, aortic characteristics and mid-term outcomes were compared between patients with and without dSINE. The extent of unfolding of the device and movement of the distal edge of the device were analyzed by multidetector computed tomography. The primary endpoints were survival and freedom from reintervention. dSINE was the most prevalent complication after FET procedure, with an incidence of 23%. Eleven of 12 patients with dSINE underwent secondary interventions. dSINE was common in chronic aortic dissection (P=0.001) and was associated with the residual false lumen area (P<0.001) and movement distance of the distal edge of the device in the cranial direction (P<0.001). The distal edge of the FET is more likely to move in the cranial direction, and this movement may cause dSINE.

Outcome of surgical repair for aortic coarctation with coexisting descending aortic aneurysm in adult patients

Objective: To evaluate the efficacy of surgical treatment of aortic coarctation combined with descending aortic aneurysm in adult patients. Methods: This is a retrospective cohort study. Adult patients with aortic coarctation who were hospitalized in Beijing Anzhen Hospital from January 2015 to April 2019 were enrolled. The aortic coarctation was diagnosed by aortic CT angiography, and the included patients were divided into the combined descending aortic aneurysm group and the uncomplicated descending aortic aneurysm group based on descending aortic diameter. General clinical data and surgery-related data were collected from the included patients, and death and complications were recorded at 30 days after surgery, and upper limb systolic blood pressure was measured in all patients at discharge. Patients were followed up after discharge by outpatient visit or telephone call for their survival and the occurrence of repeat interventions and adverse events, which included death, cerebrovascular events, transient ischemic attack, myocardial infarction, hypertension, postoperative restenosis, and other cardiovascular-related interventions. Results: A total of 107 patients with aortic coarctation aged (34.1±15.2) years were included, and 68 (63.6%) were males. There were 16 cases in the combined descending aortic aneurysm group and 91 cases in the uncomplicated descending aortic aneurysm group. In the combined descending aortic aneurysm group, 6 cases (6/16) underwent artificial vessel bypass, 4 cases (4/16) underwent thoracic aortic artificial vessel replacement, 4 cases (4/16) underwent aortic arch replacement+elephant trunk procedure, and 2 cases (2/16) underwent thoracic endovascular aneurysm repair. There was no statistically significant difference between the two groups in the choice of surgical approach (all P>0.05). In the combined descending aortic aneurysm group at 30 days after surgery, one case underwent re-thoracotomy surgery, one case developed incomplete paraplegia of the lower extremity, and one case died; and the differences in the incidence of endpoint events at 30 days after surgery were similar between the two groups (P>0.05). Systolic blood pressure in the upper extremity at discharge was significantly lower in both groups compared with the preoperative period (in the combined descending aortic aneurysm group: (127.3±16.3) mmHg vs. (140.9±16.3) mmHg, P=0.030, 1 mmHg=0.133 kPa; in the uncomplicated descending aortic aneurysm group: (120.7±13.2) mmHg vs. (151.8±26.3) mmHg, P=0.001). The follow-up time was 3.5 (3.1, 4.4) years. There were no new deaths in the combined descending aortic aneurysm group, no transient ischemic attack, myocardial infarction or re-thoracotomy surgery, and one patient (1/15) suffered cerebral infarction and 10 patients (10/15) were diagnosed with hypertension. The differences in the occurrence of endpoint events during postoperative follow-up were similar between the two groups (P>0.05). Conclusion: In experienced centers, long-term prognosis of patients with aortic coarctation combined with descending aortic aneurysm is satisfactory post surgical intervention.

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

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. 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. 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. 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.

Anatomical feasibility of an endovascular aortic arch repair with the NEXUS endograft in patients treated with a frozen elephant trunk procedure for aortic arch pathology

BackgroundThe aim of this study was to evaluate the feasibility of an endovascular repair, using the NEXUS™ Aortic Arch Stent Graft System, in a real-world cohort of patients, treated with a Frozen Elephant Trunk (FET) procedure for pathology involving the aortic arch.ResultsThe preoperative computed tomography angiography scans of 37 patients were retrospectively analyzed using a dedicated workstation. In total, seven patients (N = 7/37; 18.9%) were eligible for endovascular repair. This number increased to eleven patients (N = 11/37; 29.7%) if an additional relining of the distal aorta would be performed. Device suitability was 47.1% in patients (N = 8/17; 47.1%) with aortic arch aneurysm, 12.5% (N = 1/8; 12.5%) in patients with an acute Stanford type A dissection and 50% (N = 2/4; 50%) in patients with Crawford type II thoraco-abdominal aneurysm. The stent graft was not suitable for any of the two patients with chronic type B dissection (N = 0/2; 0%). In 22 patients (N = 22/37; 59.5%) an endovascular repair with this type of stent graft was not feasible due to an inadequate proximal sealing zone. There was no suitable brachiocephalic trunk landing zone in 13 patients (N = 13/37; 35.1%). There was no suitable distal landing zone distal in 14 patients (N = 14/37; 36.8%). This number decreased to ten patients (N = 10/37; 27.0%) when considering an additional relining of the distal aorta.ConclusionsEndovascular repair with the NEXUS single branch stent graft is feasible in a minority of this real-world cohort that underwent a Frozen Elephant Trunk procedure. However, the applicability of this device probably improves in cases with isolated aortic arch aneurysms.

Techniques and outcomes of percutaneous aortic anastomosis leak closure after frozen elephant trunk procedure for aortic dissection.

The aim of our study was to provide a summary of applied percutaneous aortic anastomosis leak (AAL) closure techniques after frozen elephant trunk (FET) procedure for aortic dissection and describe the procedural and mid-term outcomes in a consecutive cohort of patients at our center. All patients who underwent percutaneous closure of AAL after FET between January 2018 and December 2020 were identified. Three different strategies were employed: (I) the retrograde technique; (II) the true-to-false lumen loop technique; and (III) the antegrade technique. Procedural and short-term results were assessed. A total of 34 AAL closure procedures were performed in 32 patients. The mean age was 44.3±9.1 years, and 87.5% of patients were male. Successful device deployments were achieved in 36 leaks (100%). Immediate residual leaks were mild and moderate in 37.5% and 9.4% of patients, respectively. After a mean follow-up of 47.1±24.6 months, reduction in AAL to mild or less was accomplished in 90.6% of patients. Complete thrombosis and basically complete thrombosis of the FET's segment false lumen were achieved in 75.0% and 15.6% of patients, respectively. The maximal diameter of FET's segment false lumen significantly decreased by 13.6±8.7 mm (from 33.0±9.4 to 19.4±16.2 mm, P<0.001). Percutaneous closure of AAL after FET procedure was associated with false lumen reduction of aortic dissection. The magnitude of benefit was greatest with AAL reduction to a grade of mild or less. Therefore, attempts should be made to reduce AAL as much as possible.

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

ObjectiveThe 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. MethodsComputed 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. ResultsThe 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). ConclusionsThe 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.

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.

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. 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. 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. 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.