Challenges of Predicting Arteriovenous Access Survival Prior to Conversion from Catheter.

OBJECTIVE: The decision to convert from catheter to arteriovenous access is difficult yet very important. The ability to accurately predict fistula survival prior to surgery would significantly improve the decision making process. Many previously investigated demographic and clinical features have been associated with fistula failure. However, it is not conclusively understood how reliable predictions based on these parameters are on an individual level. The aim of this study was to investigate the probability of arteriovenous fistula maturation and survival after conversion using machine learning workflows. METHODS: A retrospective cohort study on multicentre data from a large North American dialysis organisation was conducted. The study population comprised 73 031 chronic in centre haemodialysis patients. The dataset included 49 variables including demographic and clinical features. Two distinct feature selection/prediction pipelines were used: LASSO regression and Boruta followed by a random forest classifier. Predictions were facilitated for re-conversion to catheter within one year. Additionally, all cause mortality predictions were conducted to serve as a comparator. RESULTS: In total, 38 151 (52.2%) had complete data and made up the main cohort. Sensitivity analyses were conducted in 67 421 patients (92.3%) after eliminating variables with a high proportion of missing data points. Selected features diverged between datasets and workflows. A previously failed arteriovenous access appears to be the most stable predictor for subsequent failure. Prediction of re-conversion based on the demographic and clinical information resulted in an area under the receiver operating characteristic curve (ROCAUC) between 0.541 and 0.571, whereas models predicting all cause mortality performed considerably better (ROCAUC 0.662 - 0.683). CONCLUSION: While group level depiction of major adverse outcomes after catheter to arteriovenous fistula/graft conversion is possible using the included variables, patient level predictions are associated with limited performance. Factors during and after fistula creation as well as biomolecular and genetic biomarkers might be more relevant predictors of fistula survival than baseline clinical conditions.

Individualizing Surveillance after Endovascular Aortic Repair Using a Modular Imaging Algorithm.

OBJECTIVES: Surveillance after endovascular aortic repair (EVAR) and fenestrated EVAR (FEVAR) is mainly directed by one-size-fits-all approaches instead of personalized decision making, even though treatment strategies and often endografts themselves are tailor-made to adjust for individual patients. We propose a modular imaging algorithm that escalates surveillance imaging based on invasiveness and need. MATERIALS AND METHODS: In this retrospective observational study of single-center data, results of a modular imaging algorithm were analyzed. The algorithm is characterized by initiating the examination with standard B-mode then transitioning to Duplex ultrasound, B-Flow, and CEUS. Additional CT(A) studies are conducted where required. The study population included both patients receiving EVAR or FEVAR. A comparative analysis was conducted regarding endoleak detection. RESULTS: The study population included 28 patients receiving EVAR and 40 patients receiving FEVAR. They accounted for 101 follow-up visits, which led to 431 distinct imaging studies. CEUS has the highest endoleak detection rate, followed by CTA and B-Flow. Duplex ultrasound and B-Flow resulted in 0 and 1 false positive cases, respectively, considering CEUS the reference standard. In a select group of six patients, CEUS was omitted after endoleaks were displayed by Duplex ultrasound or B-Flow, leading to a successful type II coiling and no aneurysm-related adverse events. CONCLUSIONS: The proposed modular algorithm showed great potential to incorporate principles of personalized medicine in surveillance after endovascular aortic treatment. Since Duplex ultrasound and B-Flow rarely cause false positive endoleaks, more resource-intensive and invasive imaging studies such as CEUS and CTA can be omitted after positive identification.

Technical Aspects and Outcome of Multi-Staged and Single-Staged Thoracoabdominal Fenestrated Endovascular Aortic Repair.

PURPOSE: In some cases of endovascular thoracoabdominal or juxtarenal aortic aneurysm repair, a thoracic endograft in combination with a fenestrated renovisceral device may be needed in order to create a sufficient proximal landing zone. This study aimed to evaluate the technical aspects and postoperative morbidity of a single- or 2-stage approach. METHODS: Eighty-seven consecutive patients undergoing thoracic endovascular aortic repair (TEVAR) in combination with elective fenestrated repair (fenestrated endovascular aortic repair [FEVAR]; fenestrated Anaconda device) from 2015 to 2022 were included in this retrospective bicentric study. Underlying pathologies, aortic morphology, technical details, and postoperative morbidity were recorded. RESULTS: Single-staged ("1S," n=61) and 2-staged ("2S," n=26) interventions were compared. Indications were thoracoabdominal aneurysms (TAAAs) (Crawford I-IV) (n=56, 64%) and juxtarenal aneurysms (n=31, 36%). In 2S, the proportion of TAAA was higher than in 1S (2S: 77%, 1S: 59%; p=0.001). In 2S, the covered length of the descending aorta was longer (1S: 128±60 mm, 2S: 202±64 mm; p=0.003). Temporary aneurysm sack perfusion (TASP) was established in 11 (18%) of 1S and 1 (4%) of 2S patients (p=0.079), as well as cerebrospinal fluid (CSF) drainage catheter in 48 (79%) of 1S and 19 (73%) of 2S. The rate of spinal cord ischemia (SCI) and the severity of SCI were not different in both groups, with a total of 3 cases of persisting paraplegia. The rate of access complications was higher in 2S (n=6, 23%) than in 1S (n=4, 7%; p=0.027). Postoperative 30 day morbidity did not significantly differ in both groups and neither did 30 day mortality (4.6% in 1S vs 3.8% in 2S; p=0.083). CONCLUSION: The combination of TEVAR and FEVAR using a fenestrated endograft is feasible and safe. Aortic morphology does not change significantly after endovascular repair. A single-staged strategy is feasible with excellent results, especially in Crawford IV, Crawford V, or juxtarenal aneurysms. Two-staged repair is recommended in cases with long aortic coverage and a higher American Society of Anesthesiologists (ASA) class. Follow-up data are needed to evaluate the long-term stability of the TEVAR/FEVAR interconnection. CLINICAL IMPACT: Our study has revealed the safety and efficacy of the combination of TEVAR and FEVAR in the treatment of TAAAs and juxtarenal aneurysms with compromised supravisceral landing zones. A single-staged concept is not necessary in all cases. Staged procedures may reduce postoperative morbidity in cases with long aortic coverage and higher ASA class.

Ultrasound Coded-Excitation Imaging for Endoleak Detection After Complex Endovascular Aortic Repair.

OBJECTIVES: Several imaging modalities have been suggested for surveillance after fenestrated endovascular aortic repair in general and endoleak detection in specific. In the present project a coded excitation-based ultrasound (B-Flow) was investigated for endoleak detection after complex endovascular aortic repair. METHODS: Patients post complex endovascular aortic repair (FEVAR or T/FEVAR) undergoing follow-up appointments including ultrasonography of the aorta at a vascular and endovascular surgery outpatient center were included in the study. B-Flow was compared with computed tomography angiography (CTA), Duplex ultrasound (DUS), and contrast-enhanced ultrasound (CEUS) regarding agreement and reliability for endoleak detection and characterization. RESULTS: In total, 47 follow-ups were included. They accumulated in a total of 149 imaging investigations. Endoleaks were discovered in 44.7% of B-Flow studies and a majority of these endoleaks were classified as type II. Agreement between B-Flow and other imaging modalities was good (>80.0%) in general. However, with B-Flow 6 and 2 endoleaks would have been missed compared with CEUS and CTA, respectively. Regarding endoleak classification, B-Flow had a strong agreement (94.5%) with CEUS in detected cases. Furthermore, in a limited subset analysis, imaging findings were externally validated using findings from angiography. CONCLUSIONS: Ultrasonography allows for endoleak detection and characterization without an invasive procedure or the use of potentially nephrotoxic contrast medium and can reduce radiation exposure. While CEUS mitigates issues of radiation and nephrotoxicity it still requires the intravenous application of contrast enhancers. Ultrasound coded-excitation imaging such as B-Flow could therefore further simplify endoleak surveillance after fenestrated endovascular aortic repair.

Endoleak Detection after Endovascular Aortic Repair via Coded-Excitation Ultrasound-A Feasibility Study.

Endoleaks are the most common complication after endovascular aortic repair (EVAR). Their correct identification is one of the main objectives of surveillance protocols after EVAR. So far, computed tomography angiography (CTA), contrast-enhanced (CEUS) and Duplex ultrasound (DUS), as well as magnetic resonance angiography, have been investigated for their ability to detect endoleaks. In general, all technologies have distinct benefits and disadvantages, with CTA and CEUS emerging as the reference standard for surveillance after EVAR. However, they are both contrast-enhancer-dependent, and CTA additionally exposes patients to ionizing radiation. In the present study, we investigated B-Flow, a type of coded-excitation ultrasound that was specifically designed to optimize the visualization of blood flow, for its ability to detect endoleaks, and compared its performance to CEUS, CTA, and DUS. In total, 34 patients were included in the analysis that accumulated in 43 distinct B-Flow investigations. They underwent a total of 132 imaging investigations. Agreement between B-Flow and other imaging modalities was high (>80.0%), while inter-method reliability can be interpreted as good. However, with B-Flow, six and one endoleaks would have been missed compared to CEUS and CTA, respectively. Regarding endoleak classification, all metrics were lower but retained an adequate level of comparison. In a subset of patients requiring intervention, B-Flow had 100% accuracy regarding both endoleak detection and classification. Ultrasonography enables endoleak detection and classification without the need for pharmaceutical contrast enhancement or radiation. Ultrasound coded-excitation imaging in the application of B-Flow could further simplify surveillance after EVAR by offering adequate accuracy without requiring intravenous contrast enhancement. Our findings may promote subsequent investigations of coded-excitation imaging for endoleak detection and classification in the surveillance after EVAR.

The Effect of Age on Peri-Operative Outcomes after FEVAR.

INTRODUCTION: Fenestrated endovascular aortic repair (FEVAR) has become a popular custom-made treatment option for juxtarenal and pararenal aneurysms. It has been previously investigated whether octogenarians as a distinct subgroup are at increased risk for adverse outcomes after FEVAR. With diverging results and an inconclusive understanding of age as a risk factor in general, an analysis of the historical data of a single center was conducted to add to the available body of evidence and further investigate the effect of age as a continuous risk factor. METHODS: A retrospective data analysis of a prospectively maintained single-center database of all patients who underwent FEVAR at a single department of vascular surgery was performed. The main endpoint was post-operative survival. In addition to association analyses, potential confounders such as co-morbidities, complication rates, or aneurysm diameter were examined. In terms of sensitivity analyses, logistic regression models were created for the dependent variables of interest. RESULTS: During the observation period from April 2013 to November 2020, 40 patients over the age of 80 and 191 patients under the age of 80 were treated by FEVAR. The 30-day survival showed no significant difference between the groups (95.1% in octogenarians and 94.3% in patients under 80 years of age). The sensitivity analyses conducted also showed no difference between the two groups, and complication and technical success rates were comparable. The aneurysm diameter was 67 ± 13 mm in the study group and 61 ± 15 mm in those under 80 years of age. Additionally, the sensitivity analyses showed that age as a continuous variable exhibits no effect on the outcomes of interest. DISCUSSION: In the present study, age was not associated with adverse peri-operative outcomes after FEVAR, including mortality, lower technical success rates, complications, or length of hospital stay. Essentially, the most highly associated factor with hospital and ICU length of stay was time spent in surgery. However, octogenarians had a significantly larger aortic diameter at the time of treatment, which might indicate the potential introduction of bias by pre-interventional patient selection. Nevertheless, the usefulness of research on octogenarians as a distinct subgroup might be questionable regarding the scalability of results, and future studies might focus on age as a continuous risk factor instead.

Fenestrated Endovascular Aortic Repair After Failed Endovascular Aortic Repair.

PURPOSE: Fenestrated endovascular aortic repair (FEVAR) is technically more challenging when performed after a failing EVAR procedure (FEVAR after EVAR). This study aims to assess the technical outcome of FEVAR after EVAR and to identify factors that may influence complication rates. METHODS: A retrospective observational study was conducted at a single department of vascular and endovascular surgery. The rate of FEVAR after EVAR compared to primary FEVAR is reported. Complication and primary unconnected fenestration (PUF) rates as well as survival were assessed for the FEVAR after EVAR cohort. PUF rates and operating time were also compared to all primary FEVAR patients. Patient characteristics and technical factors such as number of fenestrations or use of a steerable sheath were assessed as possible influencers on technical success when performing FEVAR after EVAR. RESULTS: Two hundred and nine fenestrated devices were implanted during the study period (2013 to April 2020). Thirty-five patients (16.7% of all FEVAR patients) had undergone FEVAR after EVAR and were included in the study. Overall survival at last follow-up (20.2±19.1 months) was 82.9% in FEVAR after EVAR patients. Rates of technical failure dropped significantly after 14 procedures (42.9% vs. 9.5%; p=0.03). Primary unconnected fenestrations were seen in 3 cases of FEVAR after EVAR (8.6%) and 14 of 174 primary FEVAR cases (8.0%; p>0.99). Operating time for FEVAR after EVAR was significantly higher than for primary FEVAR (301.1±110.5 minutes vs. 253.9±103.4 minutes; p=0.02). The availability of a steerable sheath was a significant predictor of reduced risk of PUFs, whereas age and gender, number of fenestrations or suprarenal fixation of the failed EVAR did not significantly influence PUF rates. CONCLUSION: Fewer technical complications were seen over the study period in FEVAR after EVAR patients. While rates of PUFs were not different from primary FEVAR, operating time was significantly longer in patients undergoing FEVAR for failed EVAR. Fenestrated EVAR can be a valuable and safe tool to treat patients with progression of aortic disease or type Ia endoleak after EVAR but may be more complex to achieve than primary FEVAR. CLINICAL IMPACT: This retrospective study assesses the technical outcome of fenestrated endovascular aortic repair (fenestrated EVAR; FEVAR) after prior EVAR. While rates of primary unconnected fenestrations were not different from primary FEVAR, operating time was significantly longer in patients undergoing FEVAR for failed EVAR. Fenestrated EVAR after prior EVAR may be technically more challenging than primary FEVAR procedures, but could be performed with equally good results in this patient cohort. FEVAR offers a feasible treatment option for patients with progression of aortic disease or type Ia endoleak after EVAR.

Remote training and evaluation of a simulator-based training course for complex endovascular procedures.

Background: Intimate knowledge of the materials used in endovascular aortic interventions is essential for trainees and supporting staff taking part in an endovascular intervention. Training courses can help to familiarize trainees with the equipment. However, the pandemic has changed the landscape of hands-on training courses significantly. Therefore, we developed a training course including an educational recording of the procedure to transfer knowledge about the materials used during endovascular interventions and radiation exposure reduction. Methods: We produced a video depicting cannulation of the left renal artery in a silicon cast of an aorta and its major side branches under C­arm fluoroscopy. A presentation using the video was given to the trainees. The trainees were randomized into a control and an intervention group. Their performance was filmed and rated on a standardized five-point scale in the style of the OSATS global rating scale. The intervention group was remeasured after additional training time. Results: In total, 23 trainees participated in the training and agreed to have their performance recorded. The control and intervention groups showed no difference in the assessed performance metrics during their initial attempt. However, after receiving additional training, the intervention group significantly improved in all evaluated metrics. Conclusion: Our data add to the growing evidence that simulator-based training can help to increase trainees' understanding and performance of relevant skills. A standardized and evidence-based validation process for simulators could improve their acceptance in the medical field.

Acute Kidney Injury and Mortality After Fenestrated Endovascular Aortic Repair.

INTRODUCTION: Acute kidney injury (AKI) is a common complication following endovascular aortic repair (EVAR). An association of AKI with patient survival after fenestrated EVAR (FEVAR) is currently under investigation. METHODS: Patients undergoing FEVAR between April 2013 and June 2020 were included in the study. AKI was defined according to acute kidney injury network criteria. Demographic and perioperative data, complications, and survival are reported for the study cohort. The data were analyzed to identify possible predictors of AKI. RESULTS: Two hundred and seventeen patients underwent FEVAR during the study period. Survival at last follow-up (20.4 ± 20.1 mo) was 75.1%. Thirty patients experienced AKI (13.8%). Six of 30 patients with AKI (20%) died within 30 days or in-hospital and 1 (3.3%) progressed to hemodialysis. Within 1 y, renal function had recovered in 23 patients (76.7%). In-hospital mortality was higher in patients with AKI (20% versus 4.3%, P = 0.006). A higher rate of AKI was seen in patients in whom an intraoperative technical complication had been documented (38.5% versus 8.4%, P = 0.001). CONCLUSIONS: Patients undergoing FEVAR are at risk of developing AKI, especially if they experience technical intraoperative complications. Most patients see recovery of renal function within the first 30 days to 1 y, but AKI remains associated with significantly increased in-hospital mortality.

Precision Medicine in Vascular and Endovascular Surgery.

Personalized medicine and precision medicine are terms often used to refer to treatment strategies tailored specifically to individual characteristics of patients, as opposed to a one-size fits all approach [...].

Clinical Applications of B-Flow Ultrasound: A Scoping Review of the Literature.

Coded excitation ultrasound investigations have the potential to augment the resolution, increase the efficiency, and expand the possibilities of noninvasive diagnostic imaging. B-Flow ultrasound, a type of digitally encoded imaging, was developed more than 20 years ago with the aim to optimize the visualization of blood flow. It has been investigated for a plethora of applications so far. A scoping review regarding its clinical applications was conducted based on a systematic literature research. B-Flow has been investigated in various anatomic locations and pathologies. However, previous research is limited by small sample sizes, the rare occurrence of elaborate study designs, the reliance on subjective reports and qualitative data, as well as several potential biases. While results are in general promising, it should therefore still be considered an emerging technology. Nevertheless, the limitations can be addressed in future research and the potential to expand its applications make B-Flow an interesting candidate for further investigations.

[Translational medicine-Development of simulation models for training in vascular surgery]. / Translation gegen die Einbahn ­ Entwicklung von Simulationsmodellen für die gefäßchirurgische Ausbildung.

The establishment of new surgical methods and techniques is associated with a learning curve which can lead to a higher morbidity and mortality for patients during training. To counteract this problem, within the framework of surgical and endovascular training and to transfer the learning curve from the patients to the simulator, life-like models are used and tested. The benefits of such simulator training have been shown in multiple disciplines. This article presents the steps from the conception to the production and validation of a simulator for ultrasound-guided arterial and venous puncture. The goal was to develop a cost-efficient high-fidelity simulator that enables ultrasound-guided percutaneous vascular puncture, direct haptic and visual feedback and the use of some percutaneous devices in a manner as complete and life-like as possible. The finished prototype enables an ultrasound-guided puncture of arteries and veins and the model enables the deployment of endovascular devices and closure systems. To be able to provide and carry out a structured training removed from external influences and challenges is in the interest of clinical departments, trainees and ultimately patient safety. Simulation training on life-like models can provide a valuable contribution in this context and represents a welcome supplement to traditional clinical training.

Assessment of fenestrated Anaconda stent graft design by numerical simulation: Results of a European prospective multicenter study.

OBJECTIVE: A crucial step in designing fenestrated stent grafts for treatment of complex aortic abdominal aneurysms is the accurate positioning of the fenestrations. The deployment of a fenestrated stent graft prototype in a patient-specific rigid aortic model can be used for design verification in vitro, but is time and human resources consuming. Numerical simulation (NS) of fenestrated stent graft deployment using the finite element analysis has recently been developed; the aim of this study was to compare the accuracy of fenestration positioning by NS and in vitro. METHODS: All consecutive cases of complex aortic abdominal aneurysm treated with the Fenestrated Anaconda (Terumo Aortic) in six European centers were included in a prospective, observational study. To compare fenestration positioning, the distance from the center of the fenestration to the proximal end of the stent graft (L) and the angular distance from the 0° position (C) were measured and compared between in vitro testing (L1, C1) and NS (L2, C2). The primary hypothesis was that ΔL (|L2 - L1|) and ΔC (|C2 - C1|) would be 2.5 or less mm in more than 80% of the cases. The duration of both processes was also compared. RESULTS: Between May 2018 and January 2019, 50 patients with complex aortic abdominal aneurysms received a fenestrated stent graft with a total of 176 fenestrations. The ΔL and ΔC was 2.5 mm or less for 173 (98%) and 174 (99%) fenestrations, respectively. The NS process duration was significantly shorter than the in vitro (2.1 days [range, 1.0-5.2 days] vs 20.6 days [range, 9-82 days]; P < .001). CONCLUSIONS: Positioning of fenestrations using NS is as accurate as in vitro and could significantly decrease delivery time of fenestrated stent grafts.

Multicentre experience with an iliac fenestrated device.

OBJECTIVES: The aim of this study was to present a multicentre experience of technical results and mid-term follow-up using a custom-made iliac fenestrated device (Terumo Aortic, Inchinnan, Renfrewshire, UK) for the treatment of iliac aneurysms and endoleaks. METHODS: A multicentre retrospective evaluation of 22 patients (3-12 per institution) with either an iliac artery aneurysm or endoleak treated with an iliac fenestrated device was performed. Data were gathered from 3 departments of vascular and endovascular surgery at 3 European institutions. RESULTS: Ten of the included patients (45.5%) were treated for an endoleak and 12 had aorto-iliac aneurysms (54.5%). Two patients underwent bilateral fenestrated device implantation for a total of 24 devices included in this analysis. Primary technical success was 91.7% (22 of 24 implanted devices). One of the 24 internal iliac arteries could not be cannulated and was covered (primary assisted technical success rate 95.8%) and 1 patient required a relining of the stent graft due to a mid-grade stenosis opposite the internal iliac artery fenestration. Survival at the last available follow-up (mean 15.2 ± 12.0 months, range 0.5-36.6 months) was 90.9%. CONCLUSIONS: The present investigation adds to a growing body of literature on custom-made endografts and their usefulness in achieving endovascular repair without compromising blood flow via important arterial branch vessels, such as the internal iliac artery. It presents encouraging technical and mid-term follow-up data from consecutive patients treated for iliac aneurysms or endoleaks using this custom-made device. The technique may help avoid adverse sequelae associated to a coil-and-cover approach when iliac branch devices are not feasible.

Exclusion of complex aortic aneurysm with chimney endovascular aortic repair is applicable in a minority of patients treated with fenestrated endografts.

OBJECTIVES: The Medtronic Endurant II stent graft has recently received Conformité Européenne (CE) approval for the use in chimney endovascular aortic repair (ChEVAR) for the treatment for juxtarenal aortic aneurysms. The aim of this study was to assess the percentage of patients treated by fenestrated endovascular repair who would have been alternatively suitable for the treatment by the CE approved Medtronic ChEVAR. METHODS: Preoperative computed tomography scans of 100 patients who underwent fenestrated endovascular aortic repair (FEVAR) between April 2013 and February 2017 were retrospectively assessed for the applicability of the ChEVAR technique according to the Medtronic instructions for use. Eligibility criteria included an aortic neck diameter of 19-30 mm, a minimum infrarenal neck length of 2 mm, a total proximal sealing zone of at least 15 mm, thrombus in the aortic neck in ˂25% of the circumference, and maximum aortic angulations of 60° in the infrarenal, 45° in the suprarenal segment and ˂45° above the superior mesenteric artery. RESULTS: According to CE-approved inclusion criteria, 19 individuals (19%) would have been eligible for ChEVAR. In 81 patients, at least 1 measure was found outside instructions for use: (i) excluding factor was detected in 26 patients, (ii) incongruous measures in 28 patients and in 27 patients, 3-5 measures were outside the instructions for use. The most frequently identified excluding factor was an insufficient infrarenal neck at ˂2 mm length (n = 63; 63%). CONCLUSIONS: Patients with juxta- or pararenal aneurysm treated by FEVAR are in 19% of the cases alternatively suitable for the treatment by ChEVAR within CE-approved instructions for use. While ChEVAR is suitable in many emergency cases, FEVAR offers a broader applicability in an elective setting.

Decrease of peripheral resistance after intraoperative administration of iloprost in patients with and without type 2 diabetes mellitus and with peripheral arterial occlusive disease.

BACKGROUND: In many cases, Ilomedin® infusions are applied as part of a perioperative measure in patients with peripheral arterial occlusive disease because it makes a relevant vasodilatatory effect in patients with type 2 diabetes mellitus and with/without peripheral neuropathy. AIMS: A prospective case-control study was performed to investigate the effect of prostanoids on peripheral resistance in patients with type 2 diabetes mellitus and patients without type 2 diabetes mellitus, as well as the role of peripheral neuropathy in patients undergoing arterial reconstruction. METHODS: Sixty patients undergoing arterial reconstruction were enrolled. Sufficient data were collected on 38 patients. Prior to surgery, peripheral nerve conduction velocity was measured. Blood flow volume at the common femoral artery was assessed intraoperatively using a Doppler flowmeter at four time points: at baseline before arterial reconstruction (T0), after reconstruction (T1), after 5 (T2) and 10 min (T3) after intra-arterial application of 3000 ng of Ilomedin. Peripheral resistance units were calculated as a function of mean arterial pressure and flow volume using the following formula: peripheral resistance unit = mean arterial pressure (mm Hg) / flow volume (mL/min). RESULTS: Ilomedin produced an immediate and significant drop of peripheral resistance in patients without type 2 diabetes mellitus as well as in patients with type 2 diabetes mellitus. Patients with peripheral neuropathy showed a less pronounced effect to Ilomedin compared to individuals with normal nerve conduction velocity.

Ultrasound-Guided Percutaneous Arterial Puncture and Closure Device Training in a Pulsatile Model.

OBJECTIVE: The current study assesses the feasibility of in vitro practice of percutaneous puncture techniques in a pulsatile flow-model. DESIGN: Prospective, controlled, randomized study. SETTING: The percutaneous access to endovascular aortic repair is considered safe, but success rates may be dependent on surgeon experience with the technique. PARTICIPANTS: Fourteen vascular surgery trainees and consultants were enrolled and randomized to a study or control group with both groups receiving instructions by a tutor on how to perform ultrasound guided percutaneous puncture and closure using a suture-mediated closure device. The study group received additional hands-on training on a pulsatile flowmodel of the groin and the performance of both groups was then graded. Study group participants were timed during and after their training on the model. RESULTS: The study group achieved higher overall grading than the control group on a 5-point scale with higher scores indicating a better performance (mean overall scores 4.0 ± 0.7 versus 2.8 ± 1.0, respectively; p = 0.03). Experienced participants (more than 20 punctures performed before the study) achieved higher overall scores than trainees (3.8 ± 0.4 versus 2.5 ± 0.8, respectively; p = 0.01). Five participants in the study group could deploy and close the ProGlide closure device correctly without the help of a tutor while being graded (71% in the study versus 0% in the control group; p = 0.02). Study group participants improved their overall score from 3.2 ± 0.9 to 4.0 ± 0.7 during training (p = 0.02). Time needed to complete the puncture and closure reduced from 456 seconds on average before, to 302 seconds after training (p < 0.001). CONCLUSIONS: Study group participants could improve their overall score while working on the simulator. More experienced participants performed better during the simulation, which may indicate the model to be life-like and a potential skills assessment tool. Simulation training may be a valuable adjunct to traditional forms of training when teaching an endovascular technique but is limited by its reliance on simulators and demo devices.

Assessment of Pull-out Forces in TEVAR and ANACONDA FEVAR Combination and Early Clinical Results: Creation of a Proximal Landing Zone for FEVAR in Patients with Extent I and Extent IV TAAAs.

BACKGROUND: Although recent data on the treatment of thoracoabdominal aortic aneurysms (TAAAs) are promising, in some cases, the paravisceral segment of the aorta may not be suitable for a branched endograft due to space restrictions. A combination of a fenestrated aneurysm repair (FEVAR) with a thoracic aneurysm repair (TEVAR) may represent a feasible treatment option. The current investigation was performed to assess the stability of a fenestrated Anaconda device implanted into a set of thoracic endografts from different manufacturers. We then assessed our clinical results with the FEVAR/TEVAR combination. METHODS: Pull-out forces were measured in vitro after docking a fenestrated Anaconda graft within the distal end of different TEVAR devices. Anaconda devices were implanted in 28- or 30-mm thoracic tube grafts (oversizing of at least 2 mm: 13.3-21.4; minimum overlap of 15 mm). Continuously increasing longitudinal pull forces of up to 100 N were applied on an Instron Tensile Tester. Initial break point and damage to the endografts were documented. Clinical results of patients treated with such an FEVAR/TEVAR combination at our institution are presented as a second part of this study. RESULTS: Median pull-out forces ranged from 2.38 N to 55.0 N. The highest stability was achieved with 34-mm Anaconda devices in 28-mm thoracic tube grafts. Grafts with either thinner Dacron material or those featuring a polytetrafluorethylene membrane seemed especially vulnerable to punctures and tears caused by the downward-looking hooks of the Anaconda device. Between April 1, 2013 and December 31, 2018, in 28 of 172 patients treated with a fenestrated Anaconda device, prior implantation of a thoracic tube graft was necessary to create a sufficient proximal landing zone. In 25 cases (89.3%), the aneurysm was successfully treated. Although the 30-day reintervention rate in this subgroup was relatively high at 28.6%, none of these was due to a failure of the FEVAR/TEVAR combination. Upon an average follow-up of 15 months, no failure of the graft connection and no type III endoleak due to membrane damage were observed. CONCLUSIONS: The combination of a thoracic tube graft and a fenestrated Anaconda device is a viable option for the treatment of patients with Extent I or IV TAAAs with no adequate landing zone above the celiac trunk. Although pull-out testing has shown good stability with most assessed grafts, the thoracic devices with thicker Dacron membranes seemed to be especially suitable.

Prospective Study of the Iliac Branch Device E-liac in Patients with Common Iliac Artery Aneurysms: 12 Month Results.

OBJECTIVES: At 12 months follow up of the PLIANT study, clinical success and efficacy of the E-liac Stent Graft System (JOTEC GmbH, Hechingen, Germany) were evaluated. Clinical success was defined as aneurysm exclusion (no type I, III, IV endoleak) with primary patency of the internal iliac artery (IIA) and external iliac artery (EIA) on the E-liac implantation side. METHODS: In this prospective multicentre European observational study, clinical and morphological data of 45 patients (93% male, mean age 72 y) were prospectively collected in 11 European centres between July 2014 and June 2016. Forty patients underwent an aorto-iliac (three patients bilaterally) treatment and five an isolated iliac treatment. RESULTS: At 12 months follow up, data were available for 42 patients. Overall clinical success at 12 months was 90%, with a survival rate of 100%. Four patients (10%) did not achieve clinical success, one with an internal iliac artery (IIA) occlusion on the E-liac implantation side, one with an infrarenal type Ia endoleak, and two with type Ib endoleaks in IIA. At 12 months the primary patency rate in the internal iliac artery on the iliac side branch implantation side was 98%. Two patients (5%) received E-liac related re-interventions: one caused by an edge stenosis at the distal end of the graft limb in the external iliac artery (EIA) and one caused by thrombo-embolism in the external iliac artery. Thus, for the EIA, primary and secondary patency rates were 98% and 100%, respectively. CONCLUSIONS: The low device related re-intervention rate of 5%, the high survival rate of 100%, and the high primary patency rates of 98% for the IIA and EIA at 12 month follow up demonstrate the safety and efficacy of the E-liac Stent Graft System. Long term 36 month results are awaited to confirm the efficacy and durability.