[Open thoracic and thoracoabdominal aortic repair vs. f/bTEVAR - complementary or competitive?] / Offener thorakaler und thorakoabdominaler Aortenersatz vs. f/b(T)EVAR ­ komplementär oder kompetitiv?

The classical approach of open repair (OR) for thoracic and thoracoabdominal aortic pathologies, including aneurysms and dissection, has been outnumbered by the use of fenestrated/branched (thoracic) endovascular aortic repair (f/b[T]EVAR) in recent years. Providing OR for complex cases in an aortic service requires a dedicated surgical setup and a huge body of expertise in this particular field.In order to reduce specific complications, such as perioperative mortality, kidney failure, spinal cord ischemia, stroke or bowel ischemia, it is necessary to apply cerebrospinal-spinal fluid drainage, point-of-care coagulation therapy, distal and retrograde aortic perfusion and sequential clamping. Despite the predominance of endovascular solutions, the specific OR expertise is still needed for specific indications, such as young patients, connective tissue disorder or aortic graft infections.Currently, the short and mid term results for f/b(T)EVAR outweigh those for OR, including the shorter hospital stay and less invasive procedures. However, OR provides better long-term results for overall mortality, re-intervention rates and secondary complications.In conclusion, in our opinion OR is a service that is still necessary for dedicated aortic centres, but will most likely become more frequent again in the years to come.

Bovine Pericardium as New Technical Option for In Situ Reconstruction of Aortic Graft Infection.

BACKGROUND: Alloplastic aortic graft infection is a devastating complication following aortic surgery. It is associated with excessively high mortality and morbidity caused by anastomotic rupture or septicemia. Many authors consider in situ replacement after complete surgical graft removal as the method of choice. However, there is an ongoing debate about the most suitable material for reconstruction. We present our first experiences with replacing the descending and infrarenal aorta using custom-made bovine pericardium grafts. MATERIAL AND METHODS: From January 2013 to 2015, 13 patients (10 male, median age 70 years, range 53-84) were treated for 5 early-graft infections after open reconstructions and 7 late graft infections (1 TEVAR, 2 EVAR, and 4 open reconstructions), and 1 patient was treated for mycotic aneurysm. Septicemia was evident in 8 patients, whereas 5 patients were presented with low-grade infection. In all cases, graft infection was proven by a synopsis of clinical findings, laboratory tests, imaging, and microbiologic tests (positive pathogen detection in 11 patients). Cutaneous and aortoenteric fistulae were present in 3 and 4 patients, respectively. All patients received an in situ replacement using a hand-sewn xenoprosthesis or patch made from a bovine pericardium sheet. Follow-up was routinely performed 3, 12, and 24 months after discharge. RESULTS: For reconstruction, 4 pericardium tubes, 7 bifurcated grafts, and 2 large patches were implanted in situ. Technical success was 100%. Median length of hospital stay was 44 days (range, 20-136 days), with an in-hospital mortality rate of 7.7% (n = 1). Major procedure- and disease-related complications were temporary (n = 2) and permanent dialysis (n = 1), limb loss (n = 1), and long-term ventilation (n = 5). Complete infection control and initial healing could be achieved in 75% (n = 10). During the follow-up (median 9 months, range: 1-27 months), primary graft patency was 100%, and mortality was 41.7%. We observed 2 secondary ruptures due to reinfection at 4 and 7 months. CONCLUSIONS: Custom-made bovine pericardium grafts provide a good option for in situ replacement following early or late aortic graft infection. Despite of its high biocompatibility, pericardium provides not an absolute protection against ongoing retroperitoneal infection. For the treatment, the principles of septic surgery need to be applied and close follow-up is mandatory.

Aortic hemiarch hybrid repair.

BACKGROUND: Hybrid aortic arch reconstruction represents a treatment option for patients unsuitable for conventional open cardiovascular surgery. We analyzed patient outcome after hemiarch repair in zone 1 and zone 2 with regard to early and long-term results. METHODS: Between December 2004 and December 2012, a total of 47 patients underwent hemiarch repair for distal aortic arch disease. Supra-aortic debranching was performed in 23 patients for zone 1 (carotid-carotid crossover bypass) and in 24 patients for zone 2 (carotid-subclavian bypass/subclavian transposition) followed by thoracic endovascular aortic repair. All patients included had been refused for open surgery or were emergency cases. RESULTS: Mean age of the patients was 65.3 years; 51% of patients were symptomatic or presented with a contained aortic rupture. Overall technical success rate was 81%, with a 30-day mortality rate of 12.8%. A primary type Ia endoleak was observed in 19%. The mean follow-up period was 50.5 months (range, 1-93 months). Follow-up mortality was 14.9%; secondary endoleak rate was 8.5% for both groups. There was a trend of reduced primary type Ia endoleak rate for zone 2 repair compared with zone 1 (4.3% vs 14.9%; P = .07). Follow-up mortality was also improved for zone 2 repair (4.3% vs 10.6%; P = .41). Overall survival rate was 70%. CONCLUSIONS: Hemiarch hybrid repair in high-risk patients is associated with an acceptable perioperative mortality risk and long-term survival. Zone 2 represents a feasible and effective treatment option for hybrid arch repair. Zone 1 is related with relevant risk for type Ia endoleak and higher mortality during follow-up. Lifelong surveillance after hybrid repair is essential.

Aortic Vascular Graft and Endograft Infection-Patient Outcome Cannot Be Determined Based on Pre-Operative Characteristics.

Vascular graft/endograft infection (VGEI) is a serious complication after aortic surgery. This study investigates VGEI and patient characteristics, PET/CT quantification before surgical or conservative management of VGEI and post-intervention outcomes in order to identify patients who might benefit from such a procedure. PET standard uptake values (SUV) were quantitatively assessed and compared to a non-VGEI cohort. The primary endpoints were in-hospital mortality and aortic reintervention-free survival at six months. Ninety-three patients (75% male, 65 ± 10 years, 82% operated) were included. The initial operation was mainly for aneurysm (67.7%: 31% EVAR, 12% TEVAR, 57% open aortic repair). Thirty-two patients presented with fistulae. PET SUVTLR (target-to-liver ratio) showed 94% sensitivity and 89% specificity. Replacement included silver-coated Dacron (21.3%), pericardium (61.3%) and femoral vein (17.3%), yet the material did not influence the overall survival (p = 0.745). In-hospital mortality did not differ between operative and conservative treatment (19.7% vs. 17.6%, p = 0.84). At six months, 50% of the operated cohort survived without aortic reintervention. Short- and midterm morbidity and mortality remained high after aortic graft removal. Neither preoperative characteristics nor the material used for reconstruction influenced the overall survival, and, with limitations, both the in-hospital and midterm survival were similar between the surgically and conservatively managed patients.

External bleeding from femoro-crural vein bypass with aneurysmal dilation.

Deaths due to external bleeding outside the hospital setting are often suspected to involve violence. However, some disease-related causes, can also lead to fatal external bleeding. While bleeding from natural body orifices is a common end stage of non-curable gastrointestinal bleeding, fatal bleeding via newly formed skin defects is quite rare and highly suspicious in light of external impact. Reliable clarification of the source and cause of bleeding is only possible in the context of an autopsy. The reported case involves the death of a man early 60 s who bled to death as a result of rupture of a femoro-crural bypass. The rupture originated from a rare true aneurysm of an autologous femoro-crural vein bypass implanted 8 years before due to peripheral arterial occlusive disease (PAD) with gangrene. The aneurysm rupture passed all subcutaneous and skin layers leading to fatal external bleeding.

Single-center initial experience with inner-branch complex EVAR in 44 patients.

Purpose: The use of inner-branch aortic stent grafts in the treatment of complex aortic pathologies aims at broad applicability and stable bridging stent sealing compared to other endovascular technologies. The objective of this study was to evaluate the early outcomes with a single manufacturer custom-made and off-the-shelf inner-branched endograft in a mixed patient cohort. Methods: This retrospective, monocentric study between 2019 and 2022 included 44 patients treated with inner-branched aortic stent grafts (iBEVAR) as custom-made device (CMD) or off-the-shelf device (E-nside) with at least four inner branches. The primary endpoints were technical and clinical success. Results: Overall, 77% (n = 34) and 23% (n = 10) of the patients (mean age 77 ± 6.5 years, n = 36 male) were treated with a custom-made iBEVAR with at least four inner branches and an off-the-shelf graft, respectively. Treatment indications were thoracoabdominal pathologies in 52.2% (n = 23), complex abdominal aneurysms in 25% (n = 11), and type Ia endoleaks in 22.7% (n = 10). Preoperative spinal catheter placement was performed in 27% (n = 12) of patients. Implantation was entirely percutaneous in 75% (n = 33). Technical success was 100%. Target vessel success manifested at 99% (178/180). There was no in-hospital mortality. Permanent paraplegia developed in 6.8% (n = 3) of patients. The mean follow-up was 12 months (range 0-52 months). Three late deaths (6.8%) occurred, one related to an aortic graft infection. Kaplan-Meier estimated 1-year survival manifested at 95% and branch patency at 98% (177/180). Re-intervention was necessary for a total of six patients (13.6%). Conclusions: Inner-branch aortic stent grafts provide a feasible option for the treatment of complex aortic pathologies, both elective (custom-made) and urgent (off-the-shelf). The technical success rate is high with acceptable short-term outcomes and moderate re-intervention rates comparable to existing platforms. Further follow-up will evaluate long-term outcomes.

Thoracoabdominal Aortic Replacement Together with Curative Oncological Surgery in Retroperitoneal and Spinal Tumours.

Malignancies with an extended encasement or infiltration of the aorta were previously considered inoperable. This series demonstrates replacement and subsequent resection of the thoracoabdominal aorta and its large branches as an adjunct to curative radical retroperitoneal and spinal tumor resection. Five consecutive patients were enrolled between 2016 and 2020, suffering from cancer of unknown primary, pleomorphic carcinoma, chordoma, rhabdoid sarcoma, and endometrial cancer metastasis. Wide surgical resection was the only curative option for these patients. For vascular replacement, extracorporeal membrane oxygenation (ECMO) was used as a partial left-heart bypass. The early technical success rate was 100% for vascular procedures and all patients underwent complete radical tumour resection with negative margins. All patients required surgical revision (liquor leak, n = 2; hematoma, n = 3; bypass revision, n = 1; bleeding, n = 1; biliary leak, n = 1). During follow-up (average 47 months, range 22-70) primary patency rates of aortic reconstructions and arterial bypasses were 100%; no patient suffered from recurrent malignant disease. Thoracoabdominal aortic replacement with rerouting of visceral and renal vessels is feasible in oncologic patients. In highly selected young patients, major vascular surgery can push the limits of oncologic surgery further, allowing a curative approach even in extensive retroperitoneal and spinal malignancies.

Rupture risk parameters upon biomechanical analysis independently change from vessel geometry during abdominal aortic aneurysm growth.

Objective: The indication for abdominal aortic aneurysm (AAA) repair is based on a diameter threshold. However, mechanical properties, such as peak wall stress (PWS) and peak wall rupture index (PWRI), influence the individual rupture risk. This study aims to correlate biomechanical and geometrical AAA characteristics during aneurysm growth applying a new linear transformation-based comparison of sequential imaging. Methods: Patients with AAA with two sequential computed tomography angiographies (CTA) were identified from a single-center aortic database. Patient characteristics included age, gender, and comorbidities. Semiautomated segmentation of CTAs was performed using Endosize (Therenva) for geometric variables (diameter, neck configuration, α/ß angle, and vessel tortuosity) and for finite element method A4 Clinics Research Edition (Vascops) for additional variables (intraluminal thrombus [ILT]), vessel volume, PWS, PWRI). Maximum point coordinates from at least one CTA 6 to 24 months before their final were predicted for the final preoperative CTA using linear transformation along fix and validation points to estimate spatial motion. Pearson's correlation and the t test were used for comparison. Results: Thirty-two eligible patients (median age, 70 years) were included. The annual AAA growth rate was 3.7 mm (interquartile range [IQR], 2.25-5.44; P < .001) between CTs. AAA (+17%; P < .001) and ILT (+43%; P < .001) volume, maximum ILT thickness (+35%; P < .001), ß angle (+1.96°; P = .017) and iliac tortuosity (+0.009; P = .012) increased significantly. PWS (+12%; P = .0029) and PWRI (+16%; P < .001) differed significantly between both CTAs. Both mechanical parameters correlated most significantly with the AAA volume increase (r = 0.68 [P < .001] and r = 0.6 [P < .001]). Changes in PWS correlated best with the aneurysm neck configuration. The spatial motion of maximum ILT thickness was 14.4 mm (IQR, 7.3-37.2), for PWS 8.4 mm (IQR, 3.8-17.3), and 11.5 mm (IQR, 5.9-31.9) for PWRI. Here, no significant correlation with any of the aforementioned parameters, patient age, or time interval between CTs were observed. Conclusions: PWS correlates highly significant with vessel volume and aneurysm neck configuration. Spatial motion of maximum ILT thickness, PWS, and PWRI is detectable and predictable and might expose different aneurysm wall segments to maximum stress throughout aneurysm growth. Linear transformation could thus add to patient-specific rupture risk analysis. Clinical Relevance: Abdominal aortic aneurysm rupture risk assessment is a key feature in future individualized therapy approaches for patients, since more and more data are obtained concluding a heterogeneous disease entity that might not be addressed ideally looking only at diameter enlargement. The approach presented in this pilot study demonstrates the feasibility and importance of measuring peak wall stress and rupture risk indices based on predicted and actual position of maximum stress points including intraluminal thrombus.

In silico study of vessel and stent-graft parameters on the potential success of endovascular aneurysm repair.

The variety of stent-graft (SG) design variables (eg, SG type and degree of SG oversizing) and the complexity of decision making whether a patient is suitable for endovascular aneurysm repair (EVAR) raise the need for the development of predictive tools to assist clinicians in the preinterventional planning phase. Recently, some in silico EVAR methods have been developed to predict the deployed SG configuration. However, only few studies investigated how to assess the in silico EVAR outcome with respect to EVAR complication likelihoods (eg, endoleaks and SG migration). Based on a large literature study, in this contribution, 20 mechanical and geometrical parameters (eg, SG drag force and SG fixation force) are defined to evaluate the quality of the in silico EVAR outcome. For a cohort of n = 146 realizations of parameterized vessel and SG geometries, the in silico EVAR results are studied with respect to these mechanical and geometrical parameters. All degrees of SG oversizing in the range between 5% and 40% are investigated continuously by a computationally efficient parameter continuation approach. The in silico investigations have shown that the mechanical and geometrical parameters are able to indicate candidates at high risk of postinterventional complications. Hence, this study provides the basis for the development of a simulation-based metric to assess the potential success of EVAR based on engineering parameters.

Why bother: usefulness and effect of young surgeon committees in surgical societies.

Work-time constraints during surgical residency along with managing a private life usually take up the majority of the time of young surgeons. For many, work with a surgical society seems like something neither generally promising nor personally worthwhile, thus raising the question, why bother? This article sets out to show examples of the effects that surgical societies and young surgeon committees can have on surgery and residency training. Additionally, we highlight the personal side of being active on a committee. Our aim is to raise interest in participating in societal work by showing the rewarding general effects as well as personal benefits. While this article is based primarily on experiences made in Germany, we believe that aspects can be transferred to other medical systems.

Patient-specific in silico endovascular repair of abdominal aortic aneurysms: application and validation.

Non-negligible postinterventional complication rates after endovascular aneurysm repair (EVAR) leave room for further improvements. Since the potential success of EVAR depends on various patient-specific factors, such as the complexity of the vessel geometry and the physiological state of the vessel, in silico models can be a valuable tool in the preinterventional planning phase. A suitable in silico EVAR methodology applied to patient-specific cases can be used to predict stent-graft (SG)-related complications, such as SG migration, endoleaks or tissue remodeling-induced aortic neck dilatation and to improve the selection and sizing process of SGs. In this contribution, we apply an in silico EVAR methodology that predicts the final state of the deployed SG after intervention to three clinical cases. A novel qualitative and quantitative validation methodology, that is based on a comparison between in silico results and postinterventional CT data, is presented. The validation methodology compares average stent diameters pseudo-continuously along the total length of the deployed SG. The validation of the in silico results shows very good agreement proving the potential of using in silico approaches in the preinterventional planning of EVAR. We consider models of bifurcated, marketed SGs as well as sophisticated models of patient-specific vessels that include intraluminal thrombus, calcifications and an anisotropic model for the vessel wall. We exemplarily show the additional benefit and applicability of in silico EVAR approaches to clinical cases by evaluating mechanical quantities with the potential to assess the quality of SG fixation and sealing such as contact tractions between SG and vessel as well as SG-induced tissue overstresses.

A methodology for in silico endovascular repair of abdominal aortic aneurysms.

Endovascular aneurysm repair (EVAR) can involve some unfavorable complications such as endoleaks or stent-graft (SG) migration. Such complications, resulting from the complex mechanical interaction of vascular tissue, SG and blood flow or incompatibility of SG design and vessel geometry, are difficult to predict. Computational vascular mechanics models can be a predictive tool for the selection, sizing and placement process of SGs depending on the patient-specific vessel geometry and hence reduce the risk of potential complications after EVAR. In this contribution, we present a new in silico EVAR methodology to predict the final state of the deployed SG after intervention and evaluate the mechanical state of vessel and SG, such as contact forces and wall stresses. A novel method to account for residual strains and stresses in SGs, resulting from the precompression of stents during the assembly process of SGs, is presented. We suggest a parameter continuation approach to model various different sizes of SGs within one in silico EVAR simulation which can be a valuable tool when investigating the issue of SG oversizing. The applicability and robustness of the proposed methods are demonstrated on the example of a synthetic abdominal aortic aneurysm geometry.