Preoperatively-determined Red Distribution Width (RDW) predicts prolonged length of stay after single-level spinal fusion in elderly patients

Introduction

Elderly patients receiving lumbar fusion surgeries present with a higher risk profile, which necessitates a robust predictor of postoperative outcomes. The Red Distribution Width (RDW) is a preoperative routinely determined parameter that reflects the degree of heterogeneity of red blood cells. Thereby, RDW is associated with frailty in hospital-admitted patients.

Research question

This study aims to elucidate the potential of RDW as a frailty biomarker predictive of prolonged hospital stays following elective mono-segmental fusion surgery in elderly patients.

Material and methods

In this retrospective study, we included all patients with age over 75 years that were treated via lumbar single-level spinal fusion from 2015 to 2022 at our tertiary medical center. Prolonged length of stay (pLOS) was defined as a length ≥ the 3rd quartile of LOS of all included patients. Classical correlation analysis, Receiver-operating characteristic (ROC) and new machine learning algorithms) were used.

Results

A total of 208 patients were included in the present study. The median age was 77 (IQR 75-80) years. The median LOS of the patients was 6 (IQR 5-8) days. The data shows a significant positive correlation between RDW and LOS. RDW is significantly enhanced in the pLOS group. New machine learning approaches with the imputation of multiple variables can enhance the performance to an AUC of 71%.

Discussion and conclusion

RDW may serve as a predictor for a pLOS in elderly. These results are compelling because the determination of this frailty biomarker is routinely performed at hospital admission. An improved prognostication of LOS could enable healthcare systems to distribute constrained hospital resources efficiently, fostering evidence-based decision-making processes.

Comparing Different Registration and Visualization Methods for Navigated Common Femoral Arterial Access-A Phantom Model Study Using Mixed Reality

Mixed reality (MxR) enables the projection of virtual three-dimensional objects into the user's field of view via a head-mounted display (HMD). This phantom model study investigated three different workflows for navigated common femoral arterial (CFA) access and compared it to a conventional sonography-guided technique as a control. A total of 160 punctures were performed by 10 operators (5 experts and 5 non-experts). A successful CFA puncture was defined as puncture at the mid-level of the femoral head with the needle tip at the central lumen line in a 0° coronary insertion angle and a 45° sagittal insertion angle. Positional errors were quantified using cone-beam computed tomography following each attempt. Mixed effect modeling revealed that the distance from the needle entry site to the mid-level of the femoral head is significantly shorter for navigated techniques than for the control group. This highlights that three-dimensional visualization could increase the safety of CFA access. However, the navigated workflows are infrastructurally complex with limited usability and are associated with relevant cost. While navigated techniques appear as a potentially beneficial adjunct for safe CFA access, future developments should aim to reduce workflow complexity, avoid optical tracking systems, and offer more pragmatic methods of registration and instrument tracking.

Objective nasal airflow measures in relation to subjective nasal obstruction, trigeminal function, and olfaction in patients with chronic rhinosinusitis

BACKGROUND

This study aimed to determine how nasal airflow measures and trigeminal function vary among patients with chronic rhinosinusitis (CRS) versus healthy controls and whether these measures are correlated with subjective nasal obstruction (SNO), olfactory function, and CRS control.

METHODOLOGY

Participants included CRS patients and healthy controls. After a structured medical history, nasal airflow (peak nasal inspiratory flow [PNIF]; active anterior rhinomanometry [AAR]), trigeminal function (trigeminal lateralization test, CO2 sensitivity), and olfactory ("Sniffin' Sticks" odor identification test) tests were performed. SNO ratings were also obtained.

RESULTS

Sixty-nine participants were included (37 men, 32 women, mean age 51 years). There was no significant difference for objective nasal airflow between patients and controls, but CRS patients had worse SNO, trigeminal function, and olfaction compared to controls. SNO, but not objective nasal airflow tests, was negatively correlated with CO2 sensitivity and odor identification.

CONCLUSION

The perception of nasal obstruction does not only depend on nasal airflow, but may also be modulated by trigeminal function and other factors. Thus, the role of objective nasal airflow measures as a sole method of functional nasal obstruction assessment in CRS remains limited.

Transposition versus interposition method in microvascular decompression for trigeminal neuralgia: midterm analysis of both techniques in a single-center study

OBJECTIVE

Operative interposition of material between the trigeminal nerve and offending artery for surgical treatment of drug-resistant trigeminal neuralgia (TGN), following the Jannetta method, has been proven to be the most successful invasive treatment. Reexplorations of patients with recurrence of TGN have revealed nerve root irritations and scarring due to interposed material. To prevent these complications, modifications of microvascular decompression (MVD) aim at transposing the vessel away from the trigeminal nerve, without attachment of additional material to the nerve root. Given that both techniques (interposition and transposition) have been performed in the authors' institution, they decided to analyze them for the short- and midterm outcomes.

METHODS

All patients who had undergone MVD for drug-resistant TGN in the authors' institution between 2008 and 2022 were analyzed retrospectively. Outcome at discharge and follow-up was evaluated using the Barrow Neurological Institute pain intensity score. Additionally, complications and pain recurrence were assessed.

RESULTS

A total of 114 patients were operated on using transposition and 110 patients were treated using interposition. For transposition 102 patients were followed up for a median of 31.5 months, and for interposition 100 patients were followed up for a median of 95 months. At discharge 92.1% versus 94.5% of patients in the transposition and interposition groups, respectively, experienced a good outcome (Barrow Neurological Institute pain intensity scores I-III). At follow-up, 83.3% versus 85% of patients in the transposition and interposition groups, respectively, continued to demonstrate a good outcome. In 4.9% of patients in the transposition group and in 6% of patients in the interposition group, recurrence of pain occurred. Complications occurred in 24.6% of patients in the transposition and in 27.3% of those in the interposition group. The most frequent complications were facial hypesthesia (10.5% vs 11.8%, transposition vs interposition), followed by CSF leaks (2.6% vs 8.2%).

CONCLUSIONS

Transposition for MVD is an elegant way of solving vessel-nerve conflicts at the cerebellopontine angle. Similar to interposition, transposition shows positive short- and midterm outcomes for patients experiencing drug-resistant TGN. However, the main objective of transposition, which is improved prevention of recurrence and reduction of complications at the trigeminal nerve, could not be confirmed in this study.

A New Method for Common Femoral Arterial Access Using a Mixed Reality-Assisted Technique on a Phantom Model

PURPOSE

The purpose of this study was to investigate the technical feasibility and usability of a mixed reality (MiR)-assisted common femoral arterial (CFA) access technique using a sonography-assisted registration method.

MATERIALS AND METHODS

A total of 60 CFA punctures were performed on a phantom model by 2 observers. Thirty punctures were performed using MiR (MiR group) and 30 punctures were performed using a conventional sonography-guided access procedure (control group). In the MiR group, a virtual object was created based on a computed tomography (CT) angiography scan of the model and registered to the physical patient in an MiR environment utilizing a software prototype that allowed registration based on a sonography scan. Positional error assessment encompassed 4 measurements using cone beam CT scans: (1) distance of the needle tip to the centerline, (2) distance of the needle entry site from the mid-level of the ostium of the profound femoral artery, (3) angle of entry of the needle in coronal, and (4) sagittal planes. Technical success rates as well as positional errors were compared between both groups. In addition, the usability of the system was assessed according to the system usability scale (SUS).

RESULTS

Technical success was 96.7% and 100% in the MiR and control groups, respectively. The median distance between the needle tip and the centerline was 3.0 (interquartile range [IQR]: 2.0-4.6) in the MiR group and 3.2 mm (IQR: 2.3-3.9) (p=0.63) in the control group. Similarly, the median distance from the needle entry site to the mid-level of the ostium of the profound femoral artery was 3.0 mm (IQR: 2.0-5.0) in the MiR group and 4.5 mm (IQR: 2.0-7.8) (p=0.18) in the control group. The median coronal angles of needle entry were 7.5° (IQR: 6-11) and 6° (IQR: 2-12) (p=0.13), and the median sagittal angles were 50° (IQR: 47-51) and 51° (IQR: 50-55) (p<0.01) in the MiR and control groups, respectively. The mean SUS score provided by both observers was 51.3.

CONCLUSION

The feasibility of an MiR-assisted CFA access technique could be demonstrated on a phantom model. Further studies are needed to investigate the technique beyond phantom model experiments and in different anatomical settings.

CLINICAL IMPACT

This study demonstrates the technical feasibility of a Mixed-Reality-assisted common femoral arterial access procedure on a phantom model. The positional accuracy was comparable to a conventional sonography-guided technique. However, there are several limitations that need to be resolved prior to potential implementation into clinical practice. Further studies are needed to investigate its performance beyond phantom model experiments and the prototypical application requires further technical refinement to increase its usability.

Recurrent neural networks for generalization towards the vessel geometry in autonomous endovascular guidewire navigation in the aortic arch

PURPOSE

Endovascular intervention is the state-of-the-art treatment for common cardiovascular diseases, such as heart attack and stroke. Automation of the procedure may improve the working conditions of physicians and provide high-quality care to patients in remote areas, posing a major impact on overall treatment quality. However, this requires the adaption to individual patient anatomies, which currently poses an unsolved challenge.

METHODS

This work investigates an endovascular guidewire controller architecture based on recurrent neural networks. The controller is evaluated in-silico on its ability to adapt to new vessel geometries when navigating through the aortic arch. The controller's generalization capabilities are examined by reducing the number of variations seen during training. For this purpose, an endovascular simulation environment is introduced, which allows guidewire navigation in a parametrizable aortic arch.

RESULTS

The recurrent controller achieves a higher navigation success rate of 75.0% after 29,200 interventions compared to 71.6% after 156,800 interventions for a feedforward controller. Furthermore, the recurrent controller generalizes to previously unseen aortic arches and is robust towards size changes of the aortic arch. Being trained on 2048 aortic arch geometries gives the same results as being trained with full variation when evaluated on 1000 different geometries. For interpolation a gap of 30% of the scaling range and for extrapolation additional 10% of the scaling range can be navigated successfully.

CONCLUSION

Adaption to new vessel geometries is essential in the navigation of endovascular instruments. Therefore, the intrinsic generalization to new vessel geometries poses an essential step towards autonomous endovascular robotics.

Mixed reality for the assessment of aortoiliac anatomy in patients with abdominal aortic aneurysm prior to open and endovascular repair: Feasibility and interobserver agreement

OBJECTIVES

The objective is to evaluate the feasibility and interobserver agreement of a Mixed Reality Viewer (MRV) in the assessment of aortoiliac vascular anatomy of abdominal aortic aneurysm (AAA) patients.

METHODS

Fifty preoperative computed tomography angiographies (CTAs) of AAA patients were included. CTAs were assessed in a mixed reality (MR) environment with respect to aortoiliac anatomy according to a standardized protocol by two experienced observers (Mixed Reality Viewer, MRV, Brainlab AG, Germany). Additionally, all CTAs were independently assessed applying the same protocol by the same observers using a conventional DICOM viewer on a two-dimensional screen with multi-planar reconstructions (Conventional viewer, CV, GE Centricity PACS RA1000 Workstation, GE, United States). The protocol included four sets of items: calcification, dilatation, patency, and tortuosity as well as the number of lumbar and renal arteries. Interobserver agreement (IA, Cohen's Kappa, κ) was calculated for every item set.

RESULTS

All CTAs could successfully be displayed in the MRV (100%). The MRV demonstrated equal or better IA in the assessment of anterior and posterior calcification (κMRV: 0.68 and 0.61, κCV: 0.33 and 0.45, respectively) as well as tortuosity (κMRV: 0.60, κCV: 0.48) and dilatation (κMRV: 0.68, κCV: 0.67). The CV demonstrated better IA in the assessment of patency (κMRV: 0.74, κCV: 0.93). The CV also identified significantly more lumbar arteries (CV: 379, MRV: 239, p < 0.01).

CONCLUSIONS

The MRV is a feasible imaging viewing technology in clinical routine. Future efforts should aim at improving hologram quality and enabling accurate registration of the hologram with the physical patient.

"Mixed Reality" in patient education prior to abdominal aortic aneurysm repair

Background: To investigate the usability of Mixed-Reality (MR) during patient education in patients scheduled for abdominal aortic aneurysm (AAA) repair. Patients and methods: Consecutive patients scheduled for elective AAA repair were block-randomized in either the Mixed-Reality group (MR group) or the conventional group (control group). Patients of both groups were educated about open and endovascular repair of their respective AAA. The MR group was educated using a head-mounted display (HMD) demonstrating a three-dimensional virtual reconstruction of the respective patient's vascular anatomy. The control group was educated using a conventional two-dimensional monitor to display the patient's vasculature. Outcomes were informational gain as well as patient satisfaction with the educational process. (DRKS-ID: DRKS00025174). Results: 50 patients were included with 25 patients in either group. Both groups demonstrated improvements in scores in the Informational Gain Questionnaire (IGQ) when comparing pre- and post-education scores. (MR group: 6.5 points (±1.8) versus 7.9 points (±1.5); Control group: 6.2 points (±1.8) versus 7.6 points (±1.6); p<0.01) There was no significant difference between the MR group and the control group either in informational gain (MR group: 1.4±1.8; Control group: 1.4±1.8; p=0.5) nor in patient satisfaction scores (MR group: mean 18.3 of maximum 21 points (±3.7); Control group: mean 17 of 21 points (±3.6); p=0.1) Multiple regression revealed no correlation between the use of MR and informational gain or patient satisfaction. Usability of the system was rated high, and patients' subjective assessment of MR was positive. Conclusions: The use of MR in patient education of AAA patients scheduled for elective repair is feasible. While patients reported positively on the use of MR in education, similar levels of informational gain and patient satisfaction can be achieved with MR and conventional methods.

Outcomes of endovascular repair of infrarenal penetrating aortic ulcers

Background: To report technical success as well as perioperative outcomes of patients who underwent endovascular aortic repair (EVAR) of penetrating abdominal aortic ulcers ≤35 mm in diameter (PAU). Patients and methods: The abdominal aortic aneurysm (AAA) quality registry of the German institute for vascular research (DIGG) was used to identify patients with standard EVAR for infrarenal PAU ≤35 mm between 1/1/2019 and 12/31/2021. Infectious, traumatic, inflammatory PAUs, PAUs associated with connective tissue disease, PAUs following aortic dissection as well as true aneurysms were excluded. Demographics, cardiovascular comorbidity, technical success as well as perioperative morbidity and mortality were determined. Results: Amongst 11 537 patients who underwent EVAR during the study period, 405 with PAU ≤35 mm were eligible from 95 participating hospitals across Germany (22% women, 20.5% octogenarians). The median aortic diameter was 30 mm (Interquartile range 27-33). Cardiovascular comorbidities were frequent with coronary artery disease (34.8%), chronic heart failure (30.9%), history of myocardial infarction (19.8%), hypertension (76.8%), diabetes (21.7%), smoking (20.8%), history of stroke (9.4%), symptomatic lower extremity peripheral arterial disease (20%), chronic kidney disease (10.4%) and chronic obstructive pulmonary disease (9.6%). Most patients were asymptomatic (89.9%). Among the symptomatic patients, 13 presented with distal embolization (3.2%) and 3 with contained ruptures (0.7%). Technical success of endovascular repair was 98.3%. Both, percutaneous (37.1%) or femoral cut-down access approaches (58.5%) were registered. Endoleaks of any type were present with type 1 (0.5%), type 2 (6.4%) and type 3 (0.3%) endoleaks. Overall mortality was 0.5%. Perioperative complications occurred in 12 patients (3.0%). Conclusions: According to this registry data, endovascular repair of PAU is technically feasible with acceptable perioperative outcomes, but further studies investigating mid- and long-term data are needed before invasive treatment of PAU disease in an elderly and comorbid patient population should be recommended.

Systematic Review on Abdominal Penetrating Atherosclerotic Aortic Ulcers: Outcomes of Endovascular Repair

PURPOSE

To systematically review existing evidence on outcomes of endovascular repair of abdominal atherosclerotic penetrating aortic ulcers (PAUs).

MATERIAL AND METHODS

Cochrane Central Registry of Registered Trials (CENTRAL), MEDLINE (via PubMed), and Web of Science databases were systematically searched. The systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis protocol (PRISMA-P 2020). The protocol was registered in the international registry of systematic reviews (PROSPERO CRD42022313404). Studies reporting on technical and clinical outcomes of endovascular PAU repair in 3 or more patients were included. Random effects modeling was used to estimate pooled technical success, survival, reinterventions, and type 1 and type 3 endoleaks. Statistical heterogeneity was assessed using the I² statistic. Pooled results are reported with 95% confidence intervals (CIs). Study quality was assessed using an adapted version of the Modified Coleman Methodology Score.

RESULTS

Sixteen studies including 165 patients with a mean/median age ranging from 64 to 78 years receiving endovascular therapy for PAU between 1997 and 2020 were identified. Pooled technical success was 99.0% (CI: 96.0%-100%). In all, 30-day mortality was 1.0% (CI: 0%-6.0%) with an in-hospital mortality of 1.0% (CI: 0.0%-13.0%). There were no reinterventions, type 1, or type 3 endoleaks at 30 days. Median/mean follow-up ranged from 1 to 33 months. Overall, there were 16 deaths (9.7%), 5 reinterventions (3.3%), 3 type 1 (1.8%), and 1 type 3 endoleak (0.6%) during follow-up. The quality of studies was rated low according to the Modified Coleman score at 43.4 (+/- 8.5) of 85 points.

CONCLUSION

There is low-level evidence on outcomes of endovascular PAU repair. While in the short-term endovascular repair of abdominal PAU seems safe and effective, mid-term and long-term data are lacking. Recommendations with regard to treatment indications and techniques in asymptomatic PAU should be made cautiously.

CLINICAL IMPACT

This systematic review demonstrated that evidence on outcomes of endovascular abdominal PAU repair is limited. While in the short-term endovascular repair of abdominal PAU seems safe and effective, mid-term and long-term data are lacking. In the context of a benign prognosis of asymptomatic PAU and lacking standardization in current reporting, recommendations with regard to treatment indications and techniques in asymptomatic PAUs should be made cautiously.

A prospective survey study on the education and awareness about walking exercise amongst inpatients with symptomatic peripheral arterial disease in Germany

Background: To determine the adherence to supervised exercise training and underlying reasons for non-adherence amongst patients with inpatient treatment of symptomatic lower extremity peripheral arterial disease (PAD). Patients: This was a prospective questionnaire-based survey study of all consecutively treated inpatients with treatment for either intermittent claudication or chronic limb-threatening ischaemia (CLTI) surveyed at sixteen participating centres in Germany. Results: A total of 235 patients (median age 70 years) were included, thereof 29.4% females and 34.6% with CLTI. The median time from first PAD diagnosis was 4 years (IQR: 1-8). Only 11.4% have previously participated in any walking exercise programme before the index treatment, thereby 10.0% in the IC subgroup and 12.0% with CLTI. Amongst all patients, 35.6% responded they were appropriately informed about the necessity and benefits of walking exercise programmes by their hospital physicians (25.8% by general practitioners), and 65.3% agreed that adherence to supervised exercise may improve their pain-free walking distance. A total of 24.5% responded they had access to necessary information concerning local walking exercise programmes. Amongst 127 free text comments on the reasons for non-adherence to supervised exercise training, 64% of the comments contained lack of information or consent on such measures. Conclusions: Less than 12% of the patients enrolled in the current study have ever participated in a walking exercise programme during their life course. Although all practice guidelines contain corresponding class I recommendations, especially for patients suffering from IC, most patients responded that they were not appropriately informed about the necessity of exercise training along with the fact that 65% agreed that exercise may increase the pain-free walking distance. Taken all together, these results emphasise that we miss an important opportunity in the patient-physician communication. Efforts should be made to improve acceptance and application of structured walking-exercise for patients with PAD.

Contact-free transposition and interposition techniques for trigeminal neuralgia: a systematic review

INTRODUCTION

Surgical treatment for trigeminal neuralgia (TGN), by means of interposition of material between nerve and offending vessel, has been shown to be highly efficient. In recent years, treatment by means of vessel transposition has become more frequent, as in singular cases of recurrence, nerval reactions towards interposed material have been noted. In this review we research the classic microvascular decompression (MVD) techniques (interposition) as well as the more recent transposition and their effectiveness, considering patient outcomes as well as complications and recurrences.

EVIDENCE ACQUISITION

We searched online databases MEDLINE and LIVIVO, using key words trigeminal neuralgia AND transposition/ AND sling/ AND non compressive technique/ AND microvascular decompression.

EVIDENCE SYNTHESIS

We included 8 studies for transposition and 20 studies for the interposition, combining for 2045 patients (302 for transposition and 1743 for interposition). 96.1% of patients in the transposition and 93.1% in the interposition group reported a positive outcome immediately postoperatively. At follow-up, 87.4% in the transposition group (follow-up 51.2 months) and 87.9% of patients in the interposition group (follow-up 36.5 months), reported a positive outcome. 16.2% of patients in the transposition and 13.1% in the interposition group had postoperative complications. Recurrence was reported in 5.6% of patients treated with transposition and 2.3% of patients treated with interposition.

CONCLUSIONS

Transposition presents similar results concerning short- and long-term patient satisfaction for treatment of TGN as well as similar numbers of complications of recurrences as interposition. Yet, current evidence is restricted to a few retrospective studies, thus, evidence is limited so far.

Das große Verbesserungspotenzial in der multimodalen Basisbehandlung der peripheren arteriellen Verschlusskrankheit (pAVK): ein Aufruf zum flächendeckenden Ausbau der pAVK-Gehtrainingsgruppen in Deutschland

Das Gehtraining gehört zu den wichtigsten Säulen der Behandlung der peripheren arteriellen Verschlusskrankheit (pAVK). Das Gehtraining in Gruppen unter Anleitung ist dabei besonders effektiv. In Deutschland ist ein flächendeckendes Angebot von Gehtrainingsgruppen nicht verfügbar. Von der Deutschen Gesellschaft für Gefäßchirurgie und Gefäßmedizin (DGG e. V.), vertreten durch die Kommission „pAVK und diabetischer Fuß“ wurde daher eine Kampagne zur bundesweiten Förderung des Aufbaus von lokalen Gehtrainingsgruppen gestartet. In diesem Artikel wird an Gefäßmediziner appelliert, bei sich vor Ort die Gehtrainingsgruppen auszubauen und mitzugestalten. Die Wege zum Ausbau solcher Gehtrainingsgruppen werden beschrieben.

Mixed Reality in der Gefäßchirurgie – ein Scoping Review

Hintergrund „Mixed Reality“ (MR) erlaubt die Projektion von virtuellen Objekten in das Sichtfeld des Anwenders durch ein Head-mounted Display (HMD). Im gefäßchirurgischen Behandlungsspektrum könnten MR-Anwendungen in Zukunft einen Nutzen darstellen. Im folgenden Scoping Review soll eine Orientierung über die aktuelle Anwendung der genannten Technologien im Bereich der Gefäßchirurgie gegeben und Forschungsziele für die Zukunft definiert werden. Material und Methoden Es erfolgte eine systematische Literaturrecherche in PubMed (MEDLINE) mit den Suchbegriffen „aorta“, „intervention“, „endovsacular intervention“, „vascular surgery“, „aneurysm“, „endovascular“, „vascular access“ jeweils in Kombination mit „mixed reality“ oder „augmented reality“. Die Suche erfolgte nach PRISMA-Leitlinie (Preferred Reporting Items for Systematic reviews and Meta-Analyses) für Scoping Reviews. Ergebnisse Aus 547 Literaturstellen konnten 8 relevante Studien identifiziert werden. Die Suchergebnisse konnten in 2 Anwendungskategorien eingeteilt werden: (1) MR mit dem Ziel des Informationsmanagements und zur Verbesserung der periprozeduralen Ergonomie gefäßchirurgischer Eingriffe (n = 3) sowie (2) MR mit dem Ziel der intraoperativen Navigation bei gefäßchirurgischen Eingriffen (n = 5). Die Registrierung des physischen Patienten mit dem virtuellen Objekt und das Tracking von Instrumenten in der MR-Umgebung zur intraoperativen Navigation ist dabei im Fokus des wissenschaftlichen Interesses und konnte technisch erfolgreich am Phantom- und Tiermodell gezeigt werden. Die bisher vorgestellten Methoden sind jedoch mit hohem infrastrukturellem Aufwand und relevanten Limitationen verbunden. Schlussfolgerung Der Einsatz von MR im Bereich der Gefäßchirurgie ist grundsätzlich vielversprechend. Für die Zukunft sollten alternative, pragmatische Registrierungsmethoden mit entsprechender Quantifizierung des Positionierungsfehlers angestrebt werden. Die entwickelten Soft- und Hardwarelösungen sollten auf das Anforderungsprofil der Gefäßchirurgie angepasst werden. Das elektromagnetische Instrumenten-Tracking erscheint als sinnvolle, komplementäre Technologie zur Umsetzung der MR-assistierten Navigation.

Quality-dependent Deep Learning for Safe Autonomous Guidewire Navigation

Cardiovascular diseases are the main cause of death worldwide. State-of-the-art treatment often includes the process of navigating endovascular instruments through the vasculature. Automation of the procedure receives much attention lately and may increase treatment quality and unburden clinicians. However, in order to ensure the patient’s safety the endovascular device needs to be steered carefully through the body. In this work, we present a collection of medical criteria that are considered by physicians during an intervention and that can be evaluated automatically enabling a highly objective assessment. Additionally, we trained an autonomous controller with deep reinforcement learning to gently navigate within a 2D simulation of an aortic arch. Among others, the controller reduced the maximum and mean contact force applied to the vessel walls by 43% and 29%, respectively.

Aneurysmal subarachnoid hemorrhage in Germany between 2005 and 2018: a nationwide observational study

BACKGROUND

In recent decades, the global incidence of aneurysmal subarachnoid hemorrhage (aSAH) has declined. However, significant regional differences exist. We present the first comprehensive analysis of time trends in the incidence of aSAH and case fatality in Germany.

METHODS

All patients hospitalized with aSAH in Germany between 2005 and 2018 were identified using International classification of disease (ICD10) codes I60.0 to I60.7.

RESULTS

A total of 101,105 cases were included. The incidence of aSAH in Germany decreased at a mean annual rate of 0.5 % (p=0.003) from 8.9 per 100,000 population in 2005 to 8.2 in 2018. Over time, incidences of aSAH declined among patients younger than 55 years and patients aged 70-79 years, increased among ages 60-64 years and remained stable in age groups 65-69 and 85-89 years. This corresponded to an increase in the mean age of aSAH onset from 55.6 (±14.3) to 59.0 (±14.0) years. Throughout the study period, the mean age of aSAH onset was higher in women compared to men (58.3 ±14.4 years vs. 56.1 ±14.1 years). There were no changes in in-hospital case fatality (16.2 vs. 16.6%, p=0.18), but the duration of hospital stay increased significantly from 19.7 to 24.8 days (p<0.001). The most frequent aSAH associated aneurysm location was the anterior circulation throughout the entire study period.

CONCLUSIONS

In Germany, the incidence of aSAH decreased between 2005 and 2018, especially in younger parts of the population. This may reflect effects of lifestyle adjustments most pronounced in younger age groups.

Learning-based autonomous vascular guidewire navigation without human demonstration in the venous system of a porcine liver

Purpose

The navigation of endovascular guidewires is a dexterous task where physicians and patients can benefit from automation. Machine learning-based controllers are promising to help master this task. However, human-generated training data are scarce and resource-intensive to generate. We investigate if a neural network-based controller trained without human-generated data can learn human-like behaviors.

Methods

We trained and evaluated a neural network-based controller via deep reinforcement learning in a finite element simulation to navigate the venous system of a porcine liver without human-generated data. The behavior is compared to manual expert navigation, and real-world transferability is evaluated.

Results

The controller achieves a success rate of 100% in simulation. The controller applies a wiggling behavior, where the guidewire tip is continuously rotated alternately clockwise and counterclockwise like the human expert applies. In the ex vivo porcine liver, the success rate drops to 30%, because either the wrong branch is probed, or the guidewire becomes entangled.

Conclusion

In this work, we prove that a learning-based controller is capable of learning human-like guidewire navigation behavior without human-generated data, therefore, mitigating the requirement to produce resource-intensive human-generated training data. Limitations are the restriction to one vessel geometry, the neglected safeness of navigation, and the reduced transferability to the real world.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11548-022-02646-8.

Persisting Type 2 Endoleaks Following EVAR for AAA Are Associated With AAA Expansion

PURPOSE

To determine the evolution of abdominal aortic aneurysm (AAA) diameter in the presence of persisting type 2 endoleaks (pEL2) following endovascular abdominal aortic aneurysm repair (EVAR).

MATERIALS AND METHODS

This is a retrospective, single-center, case-control study. All patients with pEL2 (pEL2 group, persisting for > 12 months) between 2004 and 2018 were identified and compared with a 1:1 age- and gender-matched control with no endoleak (control group). Primary outcome measures were freedom from AAA expansion and freedom from AAA shrinkage over time. AAA diameter measurements were performed on computed tomography angiography (CTA). Secondary outcome measures were survival, AAA-related mortality, reinterventions for pEL2, incidence of secondary type 1 endoleaks (EL1), and infrarenal aortic branch vessel anatomy.

RESULTS

A total of 773 patients were treated with EVAR for AAA between 2004 and 2018. Of them, 286 patients demonstrated type 2 endoleaks (EL2) in postoperative CTA or intraoperative angiography (37%). Forty-five of 286 EL2 (15.7%) were pEL2 (pEL2 group). Freedom from AAA expansion in the pEL2 group was 100%, 96.7%, 85.2%, and 54.3% after 1, 2, 3, and 4 years, respectively, compared with 100% after 1, 2, 3, and 4 years in the control group (p<0.01). Freedom from AAA shrinkage in the pEL2 group after 1, 2, 3, and 4 years was 95.5%, 90.4%, 90.4%, and 79.1%, respectively, compared with 86.7%, 34.8%, 19.3%, and 19.3% in the control group (p<0.01). Overall survival at 1, 2, 3, and 4 years was 100%, 97.6%, 95.0% and 95.0% in the pEL2 group and 100% at 1, 2, 3, and 4 years in the control group (p=0.17). There were no AAA-related deaths in either group. Patients with pEL2 had a significantly increased number of infrarenal aortic branches (p<0.05, respectively). Eighteen patients (40.0%) in the pEL2 group underwent 34 reinterventions for pEL2, with a median follow-up (FU) of 925 days (0-4173). Clinical success was achieved in 9 patients (50.0%). Four patients (8.9%) with pEL2 developed secondary EL1 after a median FU of 1278 days (662-2121).

CONCLUSION

pEL2 are associated with AAA expansion during midterm FU. Further studies are warranted to evaluate the association of AAA expansion due to pEL2 with clinical outcomes to allow recommendations with regard to treatment indications.

[Deep vein thrombosis as a primary symptom of abdominal aortic aneurysm : Bilateral deep vein thrombosis caused by infrarenal abdominal aortic aneurysm (15 cm in diameter) with complete compression of the inferior vena cava]

This article presents the case of a 70-year-old obese patient with severe bilateral leg pain due to deep vein thrombosis. After unsuccessful venous recanalization, computed tomography angiography revealed an abdominal aortic aneurysm 15 cm in diameter with total compression of the inferior vena cava. For venous decompression as well as rupture prophylaxis, conventional open surgical repair was performed.

Mixed-Reality-Assisted Puncture of the Common Femoral Artery in a Phantom Model

Percutaneous femoral arterial access is daily practice in a variety of medical specialties and enables physicians worldwide to perform endovascular interventions. The reported incidence of percutaneous femoral arterial access complications is 3–18% and often results from suboptimal puncture location due to insufficient visualization of the target vessel. The purpose of this proof-of-concept study was to evaluate the feasibility and the positional error of a mixed-reality (MR)-assisted puncture of the common femoral artery in a phantom model using a commercially available navigation system. In total, 15 MR-assisted punctures were performed. Cone-beam computed tomography angiography (CTA) was used following each puncture to allow quantification of positional error of needle placements in the axial and sagittal planes. Technical success was achieved in 14/15 cases (93.3%) with a median axial positional error of 1.0 mm (IQR 1.3) and a median sagittal positional error of 1.1 mm (IQR 1.6). The median duration of the registration process and needle insertion was 2 min (IQR 1.0). MR-assisted puncture of the common femoral artery is feasible with acceptable positional errors in a phantom model. Future studies should aim to measure and reduce the positional error resulting from MR registration.

Distribution of Mobile Health Applications amongst Patients with Symptomatic Peripheral Arterial Disease in Germany: A Cross-Sectional Survey Study

Background: Broadly available digital and mobile health applications (also known as mHealth) have recently gained increasing attention by the vascular community, but very little is known about the dissemination and acceptance of such technologies in certain target populations. The current study aimed to determine the user behaviour and acceptance of such digital technologies amongst patients with peripheral arterial disease (PAD). Methods: A cross-sectional survey of consecutively treated inpatients at 12 university institutions, as well as one non-university institution, was conducted. All admitted patients with symptomatic PAD were surveyed for 30 consecutive days within a flexible timeframe between 1 July and 30 September 2021. The factors associated with smartphone use were estimated via backward selection within a logistic regression model with clustered standard errors. Results: A total of 326 patients participated (response rate 96.3%), thereof 102 (34.0%) were treated for intermittent claudication (IC, 29.2% women, 70 years in median) and 198 were treated for chronic limb-threatening ischaemia (CLTI, 29.5% women, 70 years in median). Amongst all of the patients, 46.6% stated that they had not changed their lifestyle and health behaviour since the index diagnosis (four years in median), and 33.1% responded that they were not aware of the reasons for all of their medication orders. Amongst all those surveyed, 66.8% owned a smartphone (IC: 70.6%, CLTI: 64.1%), thereof 27.9% needed regular user support. While 42.5% used smartphone apps, only 15.0% used mobile health applications, and 19.0% owned wearables. One out of five patients agreed that such technologies could help to improve their healthy lifestyle. Only higher age was inversely associated with smartphone possession. Conclusions: The current survey showed that smartphones are prevalent amongst patients with peripheral arterial disease, but only a small proportion used mobile health applications and a considerable number of patients needed regular user support. Almost half of the patients did not change their lifestyle and one third were not aware of the reasons for their medication orders, emphasising room for improvement. These findings can further help to guide future projects using such applications to identify those target populations that are reachable with digital interventions.

Impact of chronic kidney disease on the outcomes of infrapopliteal venous, and heparin-bonded expanded polytetrafluoroethylene bypass surgeries: A retrospective cohort study

The aim of this study was to analyze the results of infrapopliteal venous and prosthetic bypass surgeries for patients with chronic limb-threatening ischemia (CLTI) and moderate to severe chronic kidney disease (CKD). All consecutive patients undergoing infrapopliteal bypass surgeries at two academic vascular centers between March 2002 and November 2018 were included in this retrospective study. During this timeframe, infrapopliteal grafts were performed for 487 patients. Of these patients, 160 (32.9%; group 1) had normal renal function, 248 (50.9%; group 2) had moderate CKD, and 79 (16.2%; group 3) had severe CKD according to the Kidney Disease Improving Global Outcomes guidelines. After 5 years' follow-up, the primary patency rate was 46.0% and the secondary patency rate was 54.9% without statistical significance noted between the CKD groups. Limb salvage (65.3%, p = 0.024) and long-term survival (19.6%, p < 0.001) were considerably lower in patients with severe CKD. In subgroup analysis, vein grafts had significantly better long-term patency rates compared to prosthetic grafts, regardless of CKD group. However, in patients with severe CKD, patency rates of vein and heparin-bonded expanded polytetrafluoroethylene (HePTFE) grafts were comparable at the 1-year mark. Our study shows that autologous vein grafts remain the first choice for infrapopliteal bypass surgeries in patients with CKD. HePTFE grafts showed good short-term results in patients with severe CKD. Given the short life expectancy of these high-risk patients, prosthetic HePTFE grafts may be reasonable in this population if a suitable vein is absent.

Midterm outcome of biosynthetic collagen prosthesis for treating aortic and peripheral prosthetic graft infections

OBJECTIVES

To report the midterm outcomes of treating prosthetic peripheral and aortic graft infections using a biosynthetic collagen prosthesis in a tertiary vascular center.

METHODS

A retrospective analysis of all patients with prosthetic peripheral and aortic graft infections who underwent in situ reconstruction using a biosynthetic collagen prosthesis between March 2015 and November 2020 was conducted. Perioperative and midterm outcomes were analyzed.

RESULTS

A biosynthetic collagen prosthesis was used in 19 patients (14 males, median age 66 years) to reconstruct the femoral artery (n = 6), iliac artery (n = 1), and infrarenal aorta (n = 12). All patients were treated for a prosthetic vascular graft infection. The median follow-up period was 26.6 months (range 1-66 months). The 30-day graft failure rate was 15.7% (n = 3), leading to a major amputation in one patient (5.3%). All grafts were occluded aortofemoral reconstructions in patients with occluded superficial femoral artery and were treated by immediate thrombectomy. The 30-day mortality rate was 5.3% (n = 1), and survival after 3 years was 63.2%. The reinfection rate was 5.3% (n = 1). At 13.6 months, the occlusion of a femoral graft was detected in 5.3% (n = 1) and was treated with a new interposition graft. We observed no graft rupture or degeneration during follow-up.

CONCLUSIONS

Although results of in situ repair with autologous vein seem to be superior with little or none reinfection and low number of occlusions, biosynthetic collagen prostheses show acceptable midterm outcomes in terms of graft occlusion and mortality after prosthetic peripheral and aortic graft infections. Similar to other xenogenous materials, the reinfection rate is low with this prosthesis. With regard to immediate availability and easy handling, the use of a biosynthetic collagen prosthesis might be favorable compared to other replacement materials while treating prosthetic graft infections.

Short and long-term outcome after common femoral artery hybrid procedure in patients with intermittent claudication and chronic limb threatening ischemia

Background: This study aimed to evaluate the differences between the outcomes of patients with intermittent claudication (IC) and chronic limb threatening ischemia (CLTI) who underwent a hybrid procedure comprising common femoral artery endarterectomy and endovascular therapy. Patients and methods: This was a retrospective single-center study of all patients with peripheral arterial occlusive disease (PAD) who underwent the hybrid procedure between March 2007 and August 2018. The primary endpoint was primary patency after 7 years. The secondary endpoints were primary-assisted patency, secondary patency, limb salvage, and survival. Results: During the follow-up period, 427 limbs in 409 patients were treated. A total of 267 and 160 patients presented with clinical signs of IC and CLTI, respectively. The 30-day mortality was 1.4% (IC: 0% vs. CLTI: 3.8%, p=0.001). The overall 30-day major amputation rate was 1.6% (IC: 0% vs. CLTI: 4.4, p=0.001). The rates of primary and secondary patency after 7 years were 63% and 94%, respectively, in the IC group and 57% and 88%, respectively, in the CLTI group; the difference was not significant. Limb salvage (94% vs. 82%, p=0.000) and survival (58% vs. 29%, p=0.000) were significantly higher in the IC group. In a multivariate analysis, CLTI was the only risk factor for major amputation. CLTI and single vessel run-off were risk factors for death. Statin therapy was a protective factor. Conclusions: The hybrid procedure provides excellent results as a treatment option for multilevel lesions in patients with PAD. However, patients with CLTI had a shorter long-term survival and lower limb salvage rate.

[Diabetic foot syndrome-Part 2 : Revascularization, treatment alternatives, care structures, recurrency prophylaxis]

Diabetic foot syndrome (DFS) is the most frequent reason for major amputations in Germany. The majority of foot lesions are triggered by repetitive pressure in diabetic polyneuropathy. Peripheral arterial occlusive disease (PAOD) impairs wound healing and is the main risk factor for amputations. The treatment of wounds and infections as well as timely revascularization are decisive. The use of endovascular and vascular surgical methods depends on the distribution pattern and length of the occlusion processes. Both procedures are complementary. Bypass surgery is of great importance for neuroischemic DFS. Multidisciplinary centers that provide revascularization in DFS can achieve an improvement of arterial blood flow in 90% of the cases and reduce the amputation rate by up to 80%. Due to the high recurrence rate of diabetic foot lesions, measures for secondary prophylaxis are of exceptional importance (podological and orthopedic technical care, foot surgery).

[Diabetic foot syndrome-Part 1 : Definition, pathophysiology, diagnostics and classification]

There are ca. 8 million persons with diabetes mellitus living in Germany. A late sequelae of diabetes is the diabetic foot syndrome (DFS), the prevalence of which is greatly increasing. It comprises all alterations of the foot as a result of diabetic polyneuropathy as well as microvascular and macrovascular (peripheral arterial occlusive disease, PAOD) alterations. Many of the ca. 250,000 newly diagnosed diabetic foot ulcers per year become chronic wounds. Despite intensive efforts for prevention, early diagnosis and adequate wound care, ca. 13,000 persons with diabetes undergo major limb amputation in Germany every year. With consistent treatment in interdisciplinary centers and by exhausting all possible methods of wound treatment, pressure relief as well as arterial revascularization, the major amputation rate in patients with diabetic foot problems can be reduced by 80%. With a suitable strategy of prevention, the recurrence rate of foot ulcers would be reduced.

Improved stability of steerable sheath access by femoro-femoral crossover wire in branched stent graft repair of complex thoraco-abdominal aortic aneurysms

Purpose

The purpose of this study was to describe a technique to catheterize antegrade branches of a branched aortic endograft by using a steerable sheath stabilized by a through-and-through wire via a femoral access.

Technique

After implantation of a branched endovascular graft, a steerable 8.5 F sheath is advanced from the femoral access. After placing the sheath proximal to the branches, a 0.014″ through-and-through wire is established to the contralateral femoral access which is held under slight traction after the curved tip of the sheath is brought into the 180° position. Then catheterization, wire exchange and deployment of the bridging stent is done in standard fashion.

Conclusion

The use of a through-and-through wire with a steerable sheath for retrograde femoral access adds stability and precision to this technique. It has the potential to reduce the risk of preoperative stroke in complex aortic endovascular repair by avoiding upper extremity access.

Bypass Grafting vs Endovascular Therapy in Patients With Non-Dialysis-Dependent Chronic Kidney Disease and Chronic Limb-Threatening Ischemia (CRITISCH Registry)

Purpose: To report the outcomes of bypass grafting (BG) vs endovascular therapy (EVT) in patients with non-dialysis-dependent chronic kidney disease (CKD) and chronic limb-threatening ischemia (CLTI). Materials and Methods: The CRITISCH Registry is a prospective, national, interdisciplinary, multicenter registry evaluating the current practice of all available treatment options in 1200 consecutive CLTI patients. For the purposes of this analysis, only the 337 patients with non-dialysis-dependent CKD treated by either BG (n=86; median 78 years, 48 men) or EVT (n=251; median age 80 years, 135 men) were analyzed. The primary composite outcome was amputation-free survival (AFS); secondary outcomes were overall survival (OS) and amputation-free time (AFT). All outcomes were evaluated in Cox proportional hazards models; the results are reported as the hazard ratio (HR) and 95% confidence interval (CI). Results: The Cox regression analysis revealed a significantly greater hazard of amputation or death after BG (HR 1.78, 95% CI 1.05 to 3.03, p=0.028). The models for AFT and overall survival also suggested a higher hazard for BG, but the differences were not significant (AFT: HR 1.66, 95% CI 0.78 to 3.53, p=0.188; OS: HR 1.41, 95% CI 0.80 to 2.47, p=0.348). The absence of runoff vessels (HR 1.73, 95% CI 1.15 to 2.60, p=0.008) was associated with a decreased AFS. The likelihood of amputation was higher in male patients (HR 2.21, 95% CI 1.10 to 4.45, p=0.027) and was associated with a lack of runoff vessels (HR 1.95, 95% CI 0.96 to 3.95, p=0.065) and myocardial infarction (HR 3.74, 95% CI 1.23 to 11.35, p=0.020). Death was more likely in patients without runoff vessels (HR 1.76, 95% CI 1.11 to 2.80, p=0.016) and those with a higher risk score (HR 1.73, 95% CI 1.03 to 2.91, p=0.038). Conclusion: This analysis suggested that BG was associated with poorer AFS than EVT in patients with non-dialysis-dependent CKD and CLTI. Male sex, previous myocardial infarction, and the absence of runoff vessels were additionally identified as predictors of poorer outcomes.

Role of aorto(bi)femoral bypass in treatment of patients with critical limb threatening ischemia

PURPOSE

To analyse the long-term outcome of open aortic procedures in patients with critical limb threatening ischemia.

METHODS

Retrospective analysis of all patients with aortoiliac TransAtlantic Inter-Society Consensus II (TASC II), type D (TASC D) lesions extending to the femoral artery who underwent aortic bypass procedures for critical limb threatening ischemia (CLTI) or intermittent claudication (IC).

RESULTS

Over a period of 10 years, 87 patients with IC and 45 patients with CLTI received a total of 56 aortounifemoral and 76 aorto-bi-femoral bypass procedures. After 7 years, overall primary patency (82.2% [CLTI] vs. 80.5% [IC], p = .918) and overall secondary patency (88.9% [CLTI] vs. 88.5% [IC], p = .851) were similar between patients with CLTI and those with IC. Long-term-survival (66.7% vs. 71.3%, p = .356) as well as limb salvage (86.7% vs. 94.3%, p = .104) was considerably lower in the CLTI-group, but the difference was not statistically significant. In the subgroup analysis, patients with CLTI and ischemic lesions (Rutherford class 5-6) had the poorest outcome after 84 months, in terms of secondary patency (92.1% vs. 73.7%, p = .015), limb salvage (97.4% vs. 73.7%, p = .000), and long-term survival (75.0% vs. 26.3%, p = .000) compared to patients with IC. Multivariate analysis revealed significant associations for patients with Rutherford class 5-6 in terms of secondary patency (p = .037) and limb salvage (p = .015). There was a significant difference in primary patency between graft limbs with superficial femoral artery occlusion and graft limbs with patent superficial femoral artery (84.6% vs. 93.0%, p = .017).

CONCLUSIONS

Aortic bypass procedures can be used in the treatment of patients with CLTI. Moreover, results are satisfactory in patients with ischemic rest pain. However, less invasive treatments should be considered for patients with ischemic lesions.

Long-Term Outcome of Common Femoral Artery Endarterectomy In Octogenarians and Non-Octogenarians

OBJECTIVE

Arteriosclerotic disease of the common femoral artery can be treated by surgical or endovascular intervention. Elderly patients are said to have a worse outcome if treated by surgical means; however, data to support this theory are missing.

METHODS

Retrospective analysis of all patients who underwent common femoral artery endarterectomy between March 2007 and July 2018 in our clinic. Group 1 included all patients <80 years and Group 2 included all patients ⩾80 years. Endpoints were patency rates, limb salvage, and overall survival.

RESULTS

During this time period, 977 common femoral artery endarterectomies were performed. Indication was claudication in 61.5% and critical limb ischemia in 38.5%. Group 1 included 805 cases (82.4%) and Group 2 included 172 cases (17.6%). Thirty-day mortality was 2.7% (Group 1 = 1.6% versus Group 2 = 7.6%; p < 0.001) and 30-day major amputation was 1.1% (Group 1 = 0.7% versus Group 2 = 2.9%; p = .043). Primary patency and secondary patency were 84.2% and 96.8%, respectively, after 7 years. Limb salvage (93.7%, Group 1 = 94.1% versus Group 2 = 91.8%; p = .088) and overall survival (52.0%, Group 1 = 59.1% versus Group 2 = 15.7%; p = .006) were significantly different after the same time period. Multivariable analysis showed female gender to be a risk factor for loss of primary patency. Age ⩾ 80 years and ulcer or gangrene were risk factors for death. Statin use was beneficial to survival.

CONCLUSIONS

Common femoral artery endarterectomy is a safe procedure with excellent long-term results. Octogenarians have an increased risk for perioperative mortality and major amputation.

Treatment of Lymphatic Complications after Common Femoral Artery Endarterectomy

BACKGROUND

This study analyzes the outcome of lymphatic complications after a standard vascular procedure.

METHODS

This is a retrospective study including patients who had a lymphatic complication after endarterectomy and patch of the common femoral artery in our clinic between March 2007 and June 2018. Therapy of choice was selected according to wound situation and amount of lymphatic liquid. If signs of a wound infection occurred, a surgical therapy was performed; in all other cases a nonsurgical treatment (conservative treatment, radiotherapy) was chosen.

RESULTS

We performed 977 index operations, a lymphatic complication occurred in 112 cases (11.5%). In 69 cases the lymphatic complication presented as lymphatic fistula (Group 1), in 43 cases as lymphorrhea from the wound (Group 2). Nonsurgical treatment was done in 66 cases (Group 1: 76.8% vs. Group 2: 30.2%; P < 0.000), and a surgical treatment was necessary in 46 cases (Group 1: 23.2% vs. Group 2: 69.8%; P < 0.000). Indication for surgery was Szilagyi 1 infection in 25 cases, Szilagyi 2 infection in 11 cases, and Szilagyi 3 infection in 10 cases. Patients with Szilagyi 1 infections received negative wound pressure therapy (NWPT). A muscle flap in combination with an NWPT was performed in patients with Szilagyi 2 infections. In Szilagyi 3 infections, the patch was replaced; additionally, a muscle flap and an NWPT were performed. The median hospital stay was 13 days in the nonsurgical group and 22.5 days in the surgical group. We had no bleeding complications and no reinfection during follow-up. The median observation period was 23.0 months. Age ≥80 years was associated with an increased risk for lymphatic complications.

CONCLUSIONS

The therapy of lymphatic complications should be done in accordance with clinical symptoms. A nonsurgical treatment is often sufficient. However, in cases of a wound infection different surgical treatments are necessary.

Long-term results of the heparin-bonded Viabahn stent graft in femoropopliteal TASC C and D lesions with a covered stent length of minimum 25 cm

Background

Heparin-bonded covered stent grafts (Viabahn) are used to treat femoropopliteal long-segment arteriosclerotic lesions. The aim of this study was to evaluate the long-term outcome of Viabahn grafts with a covered stent length of minimum 25 cm.

Methods

We conducted a retrospective analysis of patients receiving a heparin-bonded stent graft in our clinic who met the length criteria between July 2010 and March 2018. Primary endpoints were patency rates, limb salvage and survival after five years. Secondary endpoint was the 30-day outcome including early complications.

Results

A total of 62 patients (45 male, median age 70.5 years) were included. The median arteriosclerotic lesion length was 25 cm (22.0–41.3 cm), the minimum covered stent length was 25 cm (25–46 cm). All lesions were TASC C and D lesions. The 30-day mortality was 0%, an early stent graft occlusion occurred in 8.1%. A major amputation was performed in 1.6%. Primary patency, primary assisted patency, secondary patency, limb salvage and survival were 38.5%, 45.7%, 52.4%, 92.8% and 68.9% after five years. Distal stent graft end below the femoral condyles and critical limb ischemia was associated with a significant decreased survival. The diameter of the stent had no influence on the outcome.

Conclusion

The Viabahn stent graft for long segment arteriosclerotic lesions is a feasible treatment with adequate long-term results.

Remote iliac artery endarterectomy with selective stent use at the proximal dissection zone in TransAtlantic Inter-Society Consensus C and D lesions

BACKGROUND

Remote iliac artery endarterectomy (RIAE) is a challenging technique in the treatment of arterial occlusive disease. The impact of proximal transection zone stenting on patency rates is still unclear.

METHODS

This is a retrospective analysis of all patients who underwent RIAE in our hospital between March 2007 and October 2017. A stent was used in cases with a dissection flap or a stenosis at the proximal transection zone after RIAE. In all other cases, we did not use a stent. Study end points were patency rates, limb salvage, and survival after 5 years.

RESULTS

There were 115 RIAEs performed in 108 patients. All lesions were TransAtlantic Inter-Society Consensus C (61.7%) or D (38.3%) lesions. The median follow-up time was 38.5 months (range, 0-117 months). The indications were claudication in 67.0% and critical limb ischemia in 33.0%. Group 1 (n = 56) included all patients without a stent; group 2 (n = 59) included all patients with stenting of the proximal dissection zone. Risk factors were similar between the groups. The 30-day morbidity and mortality rates between the groups were not significantly different. The primary patency rate was 81.6% (group 1, 76.2%; group 2, 87.6%; P = .286), the primary assisted patency rate was 91.9% (group 1, 94.0%; group 2, 90.0%; P = .512), and the secondary patency rate was 93.8% (group 1, 94.0%; group 2, 91.6%; P = .435) after 5 years. Limb salvage (97.2%; group 1, 100%; group 2, 94.5%; P = .084) and survival time (57.1%; group 1, 66.7%; group 2, 43.5%; P = .170) were also not significantly different between the groups. A restenosis at the transection zone occurred in 14.3% in group 1 and 1.7% in group 2 (P = .013) during follow-up. A newly formed occlusion of the hypogastric artery was seen in 5.2% of patients after RIAE.

CONCLUSIONS

RIAE is a safe procedure with excellent patency rates. However, the restenosis rate is higher in cases without stenting.

Biosynthetic vascular graft: a valuable alternative to traditional replacement materials for treatment of prosthetic aortic graft infection?

Background and Aims:

To report the experience of a tertiary vascular surgery center using Omniflow II® biosynthetic vascular grafts for treatment of prosthetic aortic graft infection.

Materials and methods:

Retrospective analysis of all patients with prosthetic graft infections who underwent in situ aortic reconstruction using Omniflow II® grafts or other conduits between March 2015 and May 2017. Early and late mortality, perioperative complications, and reinfection rate were analyzed.

Results:

Sixteen patients (14 males, median age 68.5, range 57–89) with prosthetic aortic graft infection were treated at our center. Eight patients received an Omniflow II® biosynthetic graft, two patients silver-triclosan coated grafts, three patients bovine pericardial tube grafts, and three patients composite bovine pericardial tube grafts with Omniflow II® graft extensions. Perioperative complications occurred in seven patients (43.8%). Early mortality rate was 18.7% (n = 3). In addition, four patients died during follow-up after a median of 11 months (range 0–34 months). We did not observe any reinfections. Bypass grafts were patent in all patients. No major limb amputations were performed during follow-up.

Conclusion:

Treatment of prosthetic aortic graft infection with Omniflow II® vascular grafts is feasible. Graft material seems to have an excellent resistance to infection and might be a valuable alternative to traditional replacement materials. Especially long-term durability has to be continuously monitored and documented.

EphB4 mediates resistance to antiangiogenic therapy in experimental glioma

INTRODUCTION

Alterations in vascular morphogenesis are hallmarks of antiangiogenesis-resistant tumor vessels. Vascular morphogenesis is regulated by ephrinB2-EphB4 system which may induce different biological effects depending on the oncological and molecular contexts. It was the aim of the current study to characterize the influence of EphB4 on tumor microcirculation after antiangiogenic treatment using different SF126 glioma models.

MATERIALS AND METHODS

Using an ecotropic transfection system, empty vector (pLXSN) or EphB4 (EphB4^OE) overexpressing Phoenix-ECO cells were coimplanted with SF126 glioma cells subcutaneously (dorsal skinfold chamber, DSC) and orthotopically (cranial window, CW). Tumor volume was assessed by MRI. Intravital microscopy (IVM) allowed microcirculatory analysis (total {TVD} and functional vessel density {FVD}, diameter {D}, and permeability index {PI}) before and after antiangiogenic treatment (Sunitinib: DSC: 40 mg/kg BW, 6 days; CW: 80 mg/kg BW, 4 days). Immunohistochemistry included Pecam-Desmin, Ki67, TUNEL, and Caspase 3 stainings.

RESULTS

EphB4^OE induced large and treatment-resistant tumor vessels (FVD: Control/Su: 110 ± 23 cm/cm² vs. EphB4^OE/Su: 103 ± 42 cm/cm²). Maintenance of pericyte-endothelial cell interactions (Control: 80 ± 12 vs. Control/Su: 47 ± 26%; EphB4^OE: 88 ± 9 vs. EphB4^OE/Su: 74 ± 25%) and reduced antiproliferative (Control: 637 ± 80 vs. Control/Su: 110 ± 22; EphB4^OE: 298 ± 108 vs. EphB4^OE/Su: 213 ± 80) and proapoptotic responses (Control: 196 ± 25 vs. Control / Su: 404 ± 60; EphB4^OE: 183 ± 20 vs. EphB4^OE/Su: 270 ± 66) were observed under EphB4 overexpression.

CONCLUSION

EphB4 overexpression leads to vascular resistance by altering vascular morphogenesis, pericyte coverage, and cellular proliferation/apoptosis in experimental SF126 glioma models.

[Management of Endograft Infection After EVAR and TEVAR - a Case Series and Literature Review]

Introduction Endograft infection after EVAR (Endovascular aortic repair) or TEVAR (Thoracic endovascular aortic repair) is a rare but severe complication with high mortality. As the number of patients with endovascular aneurysm repair has increased over the last decade, the number of patients with endograft infection might also have increased. However, no guideline defines the treatment of endograft infection. Diagnosis is difficult and depends on clinical symptoms, radiological imaging and blood cultures. Surgery with graft excision, debridement and revascularisation should be proposed. Several techniques and graft materials are used. Additionally long term antibiotic therapy under close control of inflammation markers is always required. Methods We conducted a retrospective analysis of all patients treated for infected aortic endografts in our hospital between January 2008 and May 2017. Study endpoints were freedom from reinfection, survival and primary patency. An extensive electronic health database search was performed to identify articles reporting endograft infection after EVAR and TEVAR. Results We detected aortic endograft infection in three patients (100% male, median age 77 years). In all cases, infrarenal endovascular aortic aneurysm repair had been performed. The infected stent grafts were removed and anatomical revascularisation performed. One homograft and two xenografts were used as graft material. No patient was treated conservatively. A causative organism was found in 2 of the 3 cases. The patients received antibiotics for 12 weeks. Thirty day mortality was 0%. During follow-up, one patient died from bowel perforation after 2 months and another from lung cancer after 92 months. There were no reinfections. Primary patency of the reconstructions was 100%. Publications report high mortality after conservative therapy of endograft infection. There is evidence for lower mortality in patients who underwent surgery. Conclusions Removal of the infected graft, anatomical revascularisation and antibiotic therapy are important for long term survival after aortic endograft infection. Conservative therapy is only warranted in patients unsuitable for surgical treatment.

Xenografts in septic vascular surgery

BACKGROUND

In general, autologous veins are the optimal replacement material for an infected vascular graft in terms of handling, durability and resistance to reinfection. In the absence of suitable autologous material, several options are available, each of which has specific advantages and drawbacks with regard to these characteristics.

METHODS

In recent years, xenogeneic materials (in particular pericardial patches from different species and biosynthetic grafts) have been increasingly used as replacement material in the setting of infections. Bovine and equine pericardial patches are applied in particular as self-made tube grafts in the aortic region and also in infections of iliacofemoral prosthetic grafts and shunt infections.

RESULTS

The results of small clinical series on durability and resistance to reinfection are promising.

CONCLUSION

It is feasible to use biosynthetic materials to replace infected intracavitary and extracavitary vascular grafts with remarkably low reinfection rates; however, the unique mechanical properties of the grafts as well as the initially increased thrombogenicity, need to be taken into consideration.

Interventional Removal of Intravascular Medical Devices: Methods and Technical Success

PURPOSE

Evaluation of the technical success rate and complications when retrieving dislocated intravascular foreign bodies.

MATERIAL AND METHODS

Between 1999 and 2015 38 patients (21 female; 17 male; Age: 17 - 92; Average 54.3 years) underwent an extraction of intravascular dislocated foreign bodies, which were not lost during a radiological intervention. The extracted material included 29 port catheters, 3 tips of tunneled dialysis catheters, 2 stents, 2 guide wires, 1 CVC tip and 1 AS occluder device. Various catheters for repositioning and extraction were used. The access was transarterial as well as transvenous. Technical success was defined as complete removal of the foreign body.

RESULTS

The technical success rate was 92.1 % (35 of 38). In 17 patients an additional catheter was necessary to reposition the foreign body in order to make it accessible for the extraction catheter. In one case a stent was relocated and remodeled within the patient and was not extracted. In another case we experienced a dislocation of a small fragment of the port catheter into the distal parts of the pulmonary artery, which couldn't be extracted. A guide wire could not be extracted as it was already adhered with the vessel wall. Peri-interventional complications were not documented.

CONCLUSION

The percutaneous extraction of dislocated intravascular foreign bodies is technically successful and poor of complications. Interventional therapy can avoid surgical removal.

KEY POINTS

• The percutaneous extraction of dislocated intravascular foreign bodies is technically successful and safe.• In most cases surgical removal can be avoided.• The gooseneck-snare catheter was mainly used for the extraction of intravascular foreign bodies. Citation Format: • Ayx I, Goessmann H, Hubauer H et al. Interventional Removal of Intravascular Medical Devices: Methods and Technical Success. Fortschr Röntgenstr 2016; 188: 566 - 573.

Tibial and peroneal bypasses in octogenarians and nonoctogenarians with critical limb ischemia

BACKGROUND

Elderly patients with critical limb ischemia are increasingly treated through interventional therapy. The outcome of tibial and peroneal bypasses in octogenarians who were unsuitable for endovascular therapy remains unclear.

METHODS

We conducted a retrospective analysis of all patients who underwent tibial or peroneal bypass surgery in our clinic between October 2007 and April 2015. In Group 1 we included all patients 80 years and older and in group 2 all patients under 80 years. Vein was used whenever possible (diameter not less than 3 mm, not more than two segments for sufficient length). Study end points were primary and secondary patency, limb salvage and survival after 3 years.

RESULTS

Indications were rest pain in 32.2% and ulcer and gangrene in 67.8%. There were 92 cases in Group 1 (median age, 85 years) and 178 in group 2 (median age, 70 years). Risk factors and indications were similar in both groups except for gender, renal insufficiency and smoking. 30-day mortality was 9.7% in group 1 and 1.1% in group 2 (P = .001). There was no significant difference in 30-day graft failure and major amputation. At 3 years primary patency in group 1 was 58.9% vs 49.7% (P = .058), secondary patency was 73.0% vs 54.7% (P = .007). Limb salvage was 80.1% in group 1 vs 73.0% in group 2 (P = .446), survival was 44.0% vs 71.2% (P = .000).

CONCLUSIONS

Our analysis showed good results in octogenarians undergoing tibial and peroneal bypass surgery with regard to patency rates and limb salvage. However, octogenarians had a significantly higher perioperative mortality rate.