Real-World Evaluation of the Off-the-Shelf Precannulated Inner-Branched Endograft for Pararenal Aortic Aneurysms

PURPOSE

To analyze the early performance and efficacy of the first commercially available off-the-shelf precannulated multibranched endograft in the endovascular repair of pararenal abdominal aortic aneurysms (PAAAs). The device received European marketing approval in late 2020.

MATERIALS AND METHODS

Between January 2021 and June 2023, a retrospective analysis of prospectively collected data from all consecutive patients with pAAAs undergoing implantation of the E-nside precannulated inner-branched endograft was conducted in 2 centers. The primary outcome measure was technical success defined as the composite endpoint of successful (1) delivery of the 24F endograft, (2) use of the precannulation tubes, and (3) implantation of the bridging stent-grafts (BSGs) to the target vessels. Main secondary endpoints were mortality, target vessel instability (TVI), absence of type I or III endoleak, reintervention, spinal cord ischemia, and supra-celiac aortic coverage.

RESULTS

Twenty-one patients (20 men, mean age: 71 years) were included in this study with a mean follow-up of 14±7.7 months. Nine patients had a symptomatic aneurysm (43%). Technical success amounted to 95% (in one patient, an iliofemoral conduit was necessary to advance the device). One out of 112 BSGs (1%, right renal artery) occluded at 30 days, resulting in freedom from TVI and reintervention rate at 12 months of 95%. No type I or III endoleaks were identified during follow-up. One patient (5%) died at 13 months due to non-aneurysm-related death, and 1 patient (5%) developed spinal cord ischemia. No other major perioperative complications were observed. Mean supra-celiac aortic coverage reached 52±8%.

CONCLUSIONS

Given the imperative need for an off-the-shelf endograft tailored to address PAAAs, the E-nside stent-graft demonstrated encouraging outcomes in this study. Nevertheless, it is essential to emphasize that the extent of aortic coverage mandates the production of a truncated variant.

CLINICAL IMPACT

The endovascular repair of urgent pararenal aortic aneurysms remains still an unsolved problem in the endovascular era since there are no available off-the-shelf dedicated fenestrated or branched endografts. This paper confirms the safety and efficacy of the off-the-shelf precannulated inner branched endograft for this specific indication.

191 Improving Consent and Legibility in Orthopaedic Surgery Through Introducing Pre-Populated Stickers

Aim

Incomplete informed consent can lead to patient dissatisfaction and litigation.1 Time constraints, legibility, human error, limit completion of consent forms, putting surgeons and trusts at risk of litigation.2 The aim of this project was to assess legibility and completeness of handwritten consent forms, with the objective to improve legibility to 100% and risks listed to 100% of those endorsed by the British Orthopaedic Association (BOA).3

Method

An initial baseline study in multiple hospitals across the UK identified 113 patients who underwent hemiarthroplasties. The consent forms were assessed for legibility and risks included, compared to those listed by the BOA. Pre-populated risks stickers were introduced in 1 district general hospital (DGH) and 2 cycles repeated again (62 patients identified).

Results

Overall, 35% of consent forms 1 were illegible; 100% of the time in the risks section. Mean number of risks missing was 2.34 and most frequently missed risk was ‘death’ (missing on 35.5% of consent forms). In the DGH that introduced stickers, consent forms were 100% legible and 100% compliant to the standards set by the BOA when the stickers were used. However, sticker use remained low; only used 20% of the time in the second cycle, marginally increased from the previous cycle (18%).

Conclusions

A high proportion of consent forms are not completed to BOA standards and are illegible. Pre-populated stickers could aid in achieving 100% legibility and 100% risk inclusion. The stickers will be implemented in other trusts and methods to increase compliance with sticker use will be trialled.

408 The Swiss Cheese Effect: Following Lower Limb Emergency Admissions Through Hospital

Introduction

The Swiss cheese model analyses failure in a system: when holes align this creates ‘a trajectory of accident opportunity’. In healthcare this could translate to morbidity and/or mortality of patients. We investigated potential points of failure in treating lower limb injury patients through their hospital journey. Three points were investigated: (1) prescription of venous thrombo-embolism (VTE) prophylaxis, (2) operation note information and legibility (3) time delay in post-operative blood tests.

Method

A total of 105 patients of emergency lower limb surgical patients were identified retrospectively from two centres across the North West Region between the 31/07/20 and 21/11/20. Data was collected on (1) prescription of thrombo-prophylaxis, (2) information recorded, and legibility of operation notes as per RCSEng and (3) time delay in post-operative full blood count when compared to operation note recommendation.

Results

We found that between 10-55% of patients were prescribed anti-embolism stockings versus 100% given chemical anti-coagulation on day 1 of admission. Of a total of 23 data points, the mean number of points missing on operative notes was 4.90 (range: 2-10). A total of 82.5% handwritten operation notes were deemed legible. Post-operative full blood counts were ordered in 83.3% of patients, with the first order ranging between 1-5 days post operatively.

Conclusions

The cumulative effect of having these errors at all three points greatly increases the chance of morbidity/mortality of patients. Our experience demonstrates a failure to meet trust and Royal College of Surgeon’s guidelines. We aim to re-audit this nationally with our planned intervention.

Comparison of second-generation stents for application in the superficial femoral artery: an in vitro evaluation focusing on stent design

PURPOSE

To examine and compare in an ex vivo study different nitinol stent designs intended for the superficial femoral artery (SFA) with regard to the appearance of fracture.

METHODS

Seven different 8-×40-mm nitinol stents were evaluated (Misago, Absolute, Smart, Luminexx, Sentinol, Lifestent NT, and Sinus-Superflex). Finite element analysis (FEA) was used for digitalized stent design comparison; the strain during stent movement was calculated for bending, compression, and torsion. Additional mechanical fatigue tests for bending (70°), compression (40%), and torsion (twisted counterclockwise by 180°) were performed up to 650,000 cycles or until a fracture was observed.

RESULTS

The FEA bending test showed that only the Misago, LifeStent, and Absolute stents presented no zones of high strain; in the torsion test, the Smart stent also had no zones of high strain. Macroscopic evaluation after mechanical bending indicated that the LifeStent performed the best (no stent fracture after 650,000 cycles). Misago and Absolute stents showed fractures at 536,000 cycles and 456,667 cycles, respectively (range 320,000-650,000 cycles). After compression and torsion testing, Misago showed no stent fracture after 650,000 cycles. The worst performing stent was Luminexx during all test cycles.

CONCLUSION

The 7 SFA stents showed differences in the incidence of high strain zones, which indicates a potential for stent fracture, as demonstrated by the mechanical fatigue tests. Differences in stent design might play a major role in the appearance of stent strut fracture related to restenosis and reocclusion.

Safety and efficacy of directional atherectomy for the treatment of in-stent restenosis of the femoropopliteal artery

AIM

The aim of this study was to evaluate safety and efficacy of directional atherectomy with the Silver HawkTM device as first line treatment for in-stent restenosis of the femoropopliteal artery.

METHODS

Over a period of 1.5 years in-stent restenosis of the femoropopliteal artery in 35 lesions (34 legs, 33 patients) was primarily treated with directional atherectomy. Primary endpoint was treatment success (<50% residual stenosis) and the absence of complications. Secondary endpoint was target lesion patency after 3, 6 and 12 month assessed by duplexsonography.

RESULTS

Mean patient age was 70 years (SD+/-10). 74 % were claudicants (Rutherford 2-3), 26% had CLI (Ruther-ford (4-5). 45% were diabetics, 82% had a history of arterial hypertension and nicotine abuse. Mean lesion length was 108 mm (SD+/-102 mm). Treatment success with atherectomy alone was achieved in 86% with additional PTA (43%) success increased to 97%. Adjunctive stent implantation was necessary in 11% of the cases. Post interventional ABI increased from 0.54 (+/-0.26) to 0.77 (+/-0.26). The rate of minor complication was 3% (1/34) and the rate of major complication was 18% (6/34), mainly due to distal embolization. Target lesion patency at 3 month was 86.2%, at 6 month 68% and at 12 month 25%.

CONCLUSIONS

Although atherectomy of in-stent restenosis as a first line treatment yields a high initial success rate with a low requirement for adjunctive PTA and stent implantation, long term patency rates are low. In our study the theoretical advantage of avoiding barotauma did not result in prevention of recurrent intimal hyperplasia.

Detection of artificial air space opacities with digital radiography: ex vivo study on enhanced latitude post-processing

PURPOSE

To evaluate in a.-p. digital chest radiograms of an ex vivo system if increased latitude and enhanced image detail contrast (EVP) improve the accuracy of detecting artificial air space opacities in parts of the lung that are superimposed by the diaphragm.

MATERIALS AND METHODS

19 porcine lungs were inflated inside a chest phantom, prepared with 20-50 ml gelatin-stabilized liquid to generate alveolar air space opacities, and examined with direct radiography (3.0 × 2.5 k detector/ 125 kVp/ 4 mAs). 276 a.-p. images with and without EVP of 1.0-3.0 were presented to 6 observers. 8 regions were read for opacities, the reference was defined by CT. Statistics included sensitivity/specificity, interobserver variability, and calculation of Az (area under ROC curve).

RESULTS

Behind the diaphragm (opacities in 32/92 regions), the median sensitivity increased from 0.35 without EVP to 0.53-0.56 at EVP 1.5-3.0 (significant in 5/6 observers). The specificity decreased from 0.96 to 0.90 (significant in 6/6), and the Az value and interobserver correlation increased from 0.66 to 0.74 and 0.39 to 0.48, respectively. Above the diaphragm, the median sensitivity for artificial opacities (136/276 regions) increased from 0.71 to 0.77-0.82 with EVP (significant in 4/6 observers). The specificity and Az value decreased from 0.76 to 0.62 and 0.74 to 0.70, respectively, (significant in 3/6).

CONCLUSION

In this ex vivo experiment, EVP improved the diagnostic accuracy for artificial air space opacities in the superimposed parts of the lung (area under the ROC curve). Above the diaphragm, the accuracy was not affected due to a tradeoff in sensitivity/specificity.

Embolic protection devices for peripheral application: wasteful or useful?

Distal embolization following percutaneous intervention is a universal phenomenon that has been reported in various vascular beds. Distal emboli are also very common during lower extremity percutaneous peripheral interventions. Some data from case reports and registries are currently available. Clinical data have shown that the application of an embolic protection device in the lower limb arteries is safe. Prospective and, ideally, randomized trial data are warranted to justify the increased use of filters in lower extremity interventions, despite the obvious benefits that these devices provide. However, the clinical relevance of distal embolization in the lower extremity remains unquantified.

Comparison of carotid stents: an in-vitro experiment focusing on stent design

PURPOSE

To examine and compare different carotid stent designs with regard to flexibility, adaptability (adjustability), conformability (compliance) to the vessel, and scaffolding to reduce plaque prolapse and embolization.

METHODS

Six stents of different design were compared (Precise, Acculink, Protégé, Xact, Wallstent, and Cristallo Ideale). Optical microscopy was used to determine exact dimensions and scaffolding of each stent. Radial force was tested using a parallel plate setup, and flexibility (torsion and bending) was measured in water at body temperature. Particle penetration simulation was performed using plastic spheres from 1.5- to 6.0-mm outer diameter.

RESULTS

Stent dimensions met the manufacturers' data; none of the products showed any failure during the test program. Cell sizes in the middle part of the stents ranged from 1.36 mm(2) (Wallstent) to 15.10 mm(2) (Acculink). Bending forces at 20 degrees /30 degrees ranged from 0.063 N / 0.074 N (Cristallo Ideale) to 0.890 N / 0.616 N (Xact); forces to achieve torsion at 10 degrees /15 degrees ranged from 0.032 N / 0.043 N (Acculink) to 0.905 N / 1.071 N (Xact). According to the parallel plate method, mean lowest force was measured for Xact (0.765 N), while the Wallstent had the highest force (2.136 N). Mean radial force measurements were lowest for Cristallo Ideale (9.06 N at mid part) and highest for Protégé (24.09 N). The Cristallo Ideale stent at mid part resisted penetration by all but the smallest plastic spheres (1.5-mm spheres penetrated only at 0.65 N); the Precise and Protégé stent had the highest variation in sphere penetration (1.5- to 4.0-mm spheres). Only the Acculink let 6-mm spheres penetrate.

CONCLUSION

Despite comparable stent sizes, these carotid stents showed differences in behavior due to stent design. The open-cell design displayed the greatest flexibility and adaptability to the vessel but easily allowed particle penetration due to the open structure. Closed-cell designs had low flexibility and thus low adaptability to the vessel but high resistance to particle penetration due to the closed-cell design and high scaffolding. The hybrid stent design (Cristallo Ideale) was able to combine both the flexibility of an open-cell structure and the resistance to particle penetration of closed-cell structures.

Endovaskuläre Behandlung arteriosklerotisch bedingter arterieller Stenosen und Okklusionen der Aortenbogengefäße: Mittelfristige Ergebnisse einer Ein-Center-Analyse

OBJECTIVE

To determine mid-term patency rates after endovascular treatment of supraaortic atherosclerotic arterial stenoses and occlusions using percutaneous transluminal angioplasty (PTA) and stent placement.

PATIENTS AND METHODS

During a period of 83 months, 48 patients (18 female, 30 male; mean age 61 years, range 31-82 years) were included into this prospective single-center study. Fifty-five lesions of the brachial and cephalic arteries (subclavian/axillary artery n = 42, innominate artery n = 7, origin common carotid artery n = 6) were treated using PTA (n = 38), PTA plus stent (n = 11) or primary stent placement (n = 6). For anticoagulation, patients received a bolus of heparin (5000 IU) intraarterially during the intervention followed by intravenous application for 24h. At discharge, life-time application of ASA (100mg/day) was initiated. Follow-up protocol included clinical examination, colour-coded duplex ultrasound and intraarterial angiography in case of re-stenosis.

RESULTS

PTA and stent placement were technically successful in all patients (100%). No major complications occurred. Of seven patients presenting with total occlusions, six were treated with stent placement. Stent implantation was also performed in all lesions located at the origin of the supraaortic arteries (n = 6). In 38 lesions, the result of PTA was satisfactory. Mean follow-up time is 22 months (range 1-83 months). During follow-up examinations, re-stenoses occurred in 10 cases (at 1 month n = 2, at 6 months n = 2, at 12 months n = 3, at 24 months n = 3). In 9 lesions, re-interventions were performed (PTA n = 7; PTA plus stent n = 2). According to Kaplan-Meier life-table analysis, cumulative primary and primary assisted patency rates are 69.5% (patients at risk n = 15; standard error 9%) and 90.6% (patients at risk n = 16; standard error 6.3%) at 20 months, respectively.

CONCLUSIONS

Endovascular treatment of atherosclerotic obstructive disease in brachial and cephalic arteries is a safe procedure showing promising mid-term patency rates.

[Does interventional therapy prolong the patency of hemodialysis fistulas and grafts?]

PURPOSE

To retrospectively evaluate procedural success and patency after endovascular treatment of acute dysfunctional hemodialysis fistulas and grafts in a non-preselected patient cohort.

MATERIALS AND METHODS

185 angiographies of hemodialysis fistulas and grafts on the upper extremities were analyzed for 120 patients (53 male, 67 female; mean-age 63.1 +/- 11.4, range 24 - 91). 70 % (n = 130) were native arteriovenous fistulas, 17 % (n = 31) were prosthetic grafts, and 13 % (n = 24) were non-specific. In total, 278 lesions requiring endovascular treatment were detected. 13 % (n = 35) of the lesions were located in the arterial inflow, 18 % (n = 49) in native arteriovenous anastomoses, 7 % (n = 19) in prosthetic grafts and 62 % (n = 171) in the venous outflow. The primary, secondary and cumulative patency after endovascular treatment was calculated.

RESULTS

In 51 % (n = 94) of the cases endovascular treatment could be performed, in 8 % (n = 14) no lesion requiring treatment was detected, and in 42 % (n = 77) intervention was not considered possible. In 45 % (n = 124) of the detected lesions endovascular treatment was successful, in 18 % (n = 51) the intervention failed, and in 37 % (n = 103) intervention was not considered possible. The complication rate was 5 % (n = 10). The primary, secondary, and cumulative patency rates for 50 % of the hemodialysis fistulas and grafts after endovascular treatment were 65, 191, and 370 days, respectively. The results differed significantly from each other with p < 0.05 in the log rank test and log rank trend test.

CONCLUSION

Endovascular treatment of acute dysfunctional hemodialysis fistulas and grafts is effective in restoring the patency for hemodialysis.

Treatment of Acute Pulmonary Embolism: Local Effects of Three Hydrodynamic Thrombectomy Devices in an Ex Vivo Porcine Model

PURPOSE

To report an ex vivo study on the local effects of hydrodynamic thrombectomy for the treatment of acute pulmonary embolism (off-label use).

METHODS

Three devices (6-F AngioJet Xpeedior and 6-F and 8-F Oasis) were used for hydrodynamic thrombectomy inside the arteries of 24 inflated and perfused porcine lung explants. Each system was used at multiple positions inside 4 intact and 4 embolized lungs in vessels measuring 2 to 4 mm, 4 to 6 mm, 6 to 8 mm, and 8 to 10 mm. Angiograms prior to, during, and after catheter positioning and system operation were used to detect arterial wall trauma and to measure local clot removal per 30-second cycle. A total of 21 vessel wall samples were subjected to scanning electron microscopy (SEM) to evaluate non-perforating lesions.

RESULTS

All systems were able to remove clot material. The average recanalized vessel length normalized to 30 seconds for vessel diameters of 2 to 4 and 8 to 10 mm, respectively, was 1.17 and 1.75 cm (AngioJet), 0.97 and 0.25 cm (6-F Oasis), and 2.2 and 1.05 cm (8-F Oasis). Perforations occurred during positioning of the 6-F Oasis (4/78 maneuvers) and 8-F Oasis (13/60), but not the AngioJet (0/89); perforations were also seen during system operation (AngioJet: 21/89 activations, 6-F Oasis: 4/78, and 8-F Oasis: 9/60; all lesions inside vessels <6 mm in diameter). SEM showed 35 lesions, 14 with perforation (contrast extravasation) and 21 without perforation (induced by the tip of the guidewire).

CONCLUSION

The AngioJet was most efficient in clot removal, followed by the 8-F Oasis. The 6-F Oasis was least efficient, but had fewest complications. According to these experiments, the tested hydrodynamic thrombectomy devices may cause perforations in vessels <6 mm in diameter. Changes in catheter design to reduce system-specific complication rates or to improve the efficacy of clot removal are warranted.

Stent Placement with the Monorail Technique for Treatment of Mesenteric Artery Stenosis

PURPOSE

To analyze the immediate and midterm success of stenting of mesenteric arteries by a monorail technique in patients with chronic mesenteric ischemia.

MATERIALS AND METHODS

In this prospective case series, 19 patients (11 male, 8 female; mean age, 62.9 +/- 10.4 y; range, 36-82 y) with 23 symptomatic stenoses of mesenteric arteries were treated with stent placement by a monorail technique in a radiologic intervention center over a period of 4.5 years. Clinical examinations and duplex sonography were used to evaluate the stents' patency and clinical success. Kaplan-Meier graphs were calculated to analyze the patency and freedom-from-symptom rate.

RESULTS

Initial technical success rate was 22/23 (96%). Mean follow-up was 17 months (range, 1-58 mo). Primary patency and primary clinical success rates were 82% and 78%, respectively. According to Kaplan-Meier tables, the patency rates were 96%, 87%, 76%, and 61% at 0, 1, 15, and 24 months, respectively, and the freedom-from-symptom rates were 95%, 90%, 72%, and 54% at 0, 1, 24, and 30 months, respectively. No peri-interventional complications occurred. Two patients died of cardiac failure in the hospital within 30 days after intervention; deaths were not related to the intervention.

CONCLUSIONS

Stent placement by a monorail technique in mesenteric arteries is an effective and safe treatment for symptomatic stenoses in patients with chronic mesenteric ischemia after a mean follow-up of 17 months.

Influence of various cell-detachment solutions on endothelial cells after catheter abrasion for prosthesis colonization prior to implantation

We (1) evaluated the effectiveness of different media on the detachment of endothelial cells (ECs) from a catheter brush (Cragg thrombolytic catheter system) that was previously used for endothelial cell abrasion in 10 cm human umbilical vein (HUV) segments; (2) tested the practicability of endovascular catheter brush abrasion followed by EC detachment from the catheter brush, in vitro culture of harvested ECs, and finally endothelialization of a prosthesis; and (3) analyzed the defect created by the catheter brush in HUV segments after endovascular catheter abrasion. Best results in detachment of ECs from the catheter brush were obtained with a mixture of phosphate-buffered saline + 1% human albumin. EC vitality was time-dependent in the collected HUV segments postdelivery. Harvested EC viability decreased from (26.28 +/- 5.76)% (0-3 h postdelivery) to (17.29 +/- 4.56)% (after 4-8 h). ECs were easily cultured ex vivo within 2-3 weeks; seeded on nitinol stents, they grew to confluency and formed a monolayer on the stent surface (determined by scanning electron microscopy - SEM). Histological and SEM analysis of HUV segments that had undergone previous catheter brush abrasion revealed slight disruption of the intima but intact subintimal layers. Our findings indicate an advantageous method of capturing and culturing primary ECs for gene therapy or for the analysis and diagnosis of certain blood vessel diseases, especially in cases in which endovascular intervention is performed anyway. Moreover, and of high relevance to the biomaterial field, theoretically the procedure could be used to endothelialze a prosthesis ex vivo for implantation into the patient from whom the ECs were harvested, to reduce the inherent thrombogenicity of the prosthesis.

Volumetric interpolated contrast-enhanced MRA for the diagnosis of pulmonary embolism in an ex vivo system

PURPOSE

To implement a three-dimensional gradient-recalled echo (GRE) volumetric interpolated breath-hold examination (VIBE) sequence for pulmonary contrast-enhanced MRA (CE-MRA) in an experimental setup.

MATERIALS AND METHODS

Eight porcine lungs were intubated, inflated inside a chest phantom, and examined at 1.5 T during slow perfusion (2-300 mL/minute). Three-dimensional-MRA was performed with and without contrast agent using three-dimensional-GRE (VIBE) with TR/TE = 4.5/1.9 msec, TA = 23 seconds, FOV = 390 mm, FA = 12 degrees /30 degrees, as well as a standard three-dimensional-GRE sequence and T2 fast spin-echo (FSE) sequences. Four of the eight lungs were embolized with autologous blood clots. By consensus readings, two observers evaluated the detectability of peripheral vessels, signal intensity over vessels and lung, and visualization of emboli. Digital subtraction angiograms served as a control to document vessel patency.

RESULTS

Prior to contrast administration, three-dimensional-VIBE/12 degrees yielded the best results for lung parenchyma signal and visualization of small vessels (third-order, P < 0.01); however, no emboli were detected (due to lack of contrast). After administration of contrast agent, three-dimensional-GRE (VIBE) at FA = 30 degrees provided significantly better results (fifth-order branches, documentation of subsegmental occlusions [fourth order], P < 0.01). T2-FSE images documented water uptake into the lungs. Digitally subtracted angiography (DSA) confirmed the patency of seventh-order branches.

CONCLUSION

This ex vivo study confirms the potential advantages of using a dual MR investigation for pulmonary embolism, combining three-dimensional-GRE (VIBE) at FA = 12 degrees to image lung parenchyma and at FA = 30 degrees for CE-MRA..

SUGGESTED GREEK TRANSLATIONS OF EXPRESSIONS IN THE EXPERIMENTAL ANALYSIS OF BEHAVIOR

Greek-English and English-Greek translations of expressions in the experimental analysis of behavior are presented. Included is a short discussion of some of the problems which arose, partly because of the mentalistic nature of Greek science.