Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

A State-of-the-Art Review of Intra-Operative Imaging Modalities Used to Quality Assure Endovascular Aneurysm Repair

Endovascular aortic aneurysm repair (EVAR) is the preferred method for elective abdominal aortic aneurysm (AAA) repair. However, the success of this technique depends greatly on the technologies available. Intra-operative imaging is essential but can come with limitations. More complex interventions lead to longer operating times, fluoroscopy times, and greater contrast doses. A number of intra-operative imaging modalities to quality assure the success of EVAR have been developed. A systematic literature search was performed with separate searches conducted for each imaging modality in the study: computed tomography (CT), digital subtraction angiography (DSA), fusion, ultrasound, intra-operative positioning system (IOPS), and non-contrast imaging. CT was effective at detecting complications but commonly resulted in increased radiation and contrast dose. The effectiveness of DSA can be increased, and radiation exposure reduced, through the use of adjunctive technologies. We found that 2D-3D fusion was non-inferior to 3D-3D and led to reduced radiation and contrast dose. Non-contrast imaging occasionally led to higher doses of radiation. Ultrasound was particularly effective in the detection of type II endoleaks with reduced radiation and contrast use but was often operator dependent. Unfortunately, no papers made it past full text screening for IOPS. All of the imaging techniques discussed have advantages and disadvantages, and clinical context is relevant to guide imaging choice. Fusion and ultrasound in particular show promise for the future.

Combined Angio-CT Systems: A Roadmap Tool for Precision Therapy in Interventional Oncology

Combined angiography-CT (angio-CT) systems, which combine traditional angiographic imaging with cross-sectional imaging, are a valuable tool for interventional radiology. Although cone-beam CT (CBCT) technology from flat-panel angiography systems has been established as an adjunct cross-sectional imaging tool during interventional procedures, the intrinsic advantages of angio-CT systems concerning superior soft-tissue imaging and contrast resolution, along with operational ease, have sparked renewed interest in their use in interventional oncology procedures. Owing to increases in affordability and usability due to an improved workflow, angio-CT systems have become a viable alternative to stand-alone flat-panel angiographic systems equipped with CBCT. This review aims to provide a comprehensive technical and clinical guide for the use of angio-CT systems in interventional oncology. The basic concepts related to the use of angio-CT systems, including concepts related to workflow setup, imaging characteristics, and acquisition parameters, will be discussed. Additionally, an overview on the clinical applications and the benefits of angio-CT systems in routine therapeutic and palliative interventional oncology procedures will be reviewed. Keywords: Ablation Techniques, CT-Angiography, Interventional-Body, Interventional-MSK, Chemoembolization, Embolization, Radiation Therapy/Oncology, Abdomen/GI, Skeletal-Axial Supplemental material is available for this article. © RSNA, 2021.

Impact of Cone Beam Computed Tomography in Advanced Endovascular Aortic Aneurysm Repair Using Last Generation 3D C-arm

BACKGROUND

To report the early outcomes of cone beam computed tomography (CBCT) using last generation 3D C-arm in patients undergone advanced endovascular aortic aneurysm repair (AdEVAR) and to identify risk factors that may predict any un-planned procedures.

METHODS

Patients undergone AdEVAR between December 2017 and December 2018 were enrolled. Final CBCT was performed in all patients after digital subtraction angiography. Primary end points were the incidence of any positive findings and the following unplanned procedures intended as any endovascular manoeuvre performed to fix such technical defect. The secondary endpoints were comparison of outcomes between patients with positive findings undergone unplanned procedure (Group A) versus patients without findings (Group B).

RESULTS

132 patients underwent endovascular treatment for aortic aneurysm. Of these, 22 (33%) fenestrated-branched endovascular aneurysm repairs (F-BEVAR), 21 (29%) EVAR with iliac branch devices, 19 (26%) abdominal and 10 (14%) thoracic EVAR were included in the study. Unplanned procedures after CBCT were necessary in 22 patients (31%). Patients in both groups were similar excepted for BMI >25 kg/m² (55% vs. 26%), hostile iliac anatomy (64% vs. 32%) and previous aortic treatment (73% vs. 32%) (P < 0.05). The odds ratios for unplanned procedure in case of previous aortic treatment was 6.76 (95% CI, 1.97-23.16; P = 0.002).

CONCLUSION

The use of CBCT, especially in challenging scenarios, can reveal technical defects and may potentially limit the need for late reintervention. Patients undergone previous aortic surgery should be carefully evaluated and routine CBCT should be performed.

Impact of Hybrid Operating Rooms on Long-Term Clinical Outcomes Following Fenestrated and Branched Endovascular Aortic Repair

PURPOSE

Evaluate the impact of hybrid operating room (HOR) guidance on the long-term clinical outcomes following fenestrated and branched endovascular repair (F-BEVAR) for complex aortic aneurysms.

MATERIALS AND METHODS

Prospectively collected registry data were retrospectively analyzed to compare the procedural, short- and long-term outcomes of consecutive F-BEVAR performed from January 2010 to December 2014 under standard mobile C-arm versus hybrid room guidance in a high-volume aortic center.

RESULTS

A total of 262 consecutive patients, including 133 patients treated with a mobile C-arm equipped operating room and 129 with a HOR guidance, were enrolled in this study. Patient radiation exposure and contrast media volume were significantly reduced in the HOR group. Short-term clinical outcomes were improved despite higher case complexity in the HOR group, with no statistical significance. At a median follow-up of 63.3 months (Q1 33.4, Q3 75.9) in the C-arm group, and 44.9 months (Q1 25.1, Q3 53.5, p=0.53) in the HOR group, there was no statistically significant difference in terms of target vessel occlusion and limb occlusion. When the endograft involved 3 or more fenestrations and/or branches (complex F-BEVAR), graft instability (36% vs 25%, p=0.035), reintervention on target vessels (20% vs 11%, p=0.019) and total reintervention rates (24% vs 15%, p=0.032) were significantly reduced in the HOR group. The multivariable Cox regression analysis did not show statistically significant differences for long-term death and aortic-related death between the 2 groups.

CONCLUSION

Our study suggests that better long-term clinical outcomes could be observed when performing complex F-BEVAR in the latest generation HOR.

Radiation Dose during Transarterial Radioembolization: A Dosimetric Comparison of Cone-Beam CT and Angio-CT Technologies

PURPOSE

To evaluate the radiation dose differences for intraprocedural computed tomography (CT) imaging between cone-beam CT and angio-CT acquired during transarterial radioembolization (TARE) therapies for hepatocellular carcinoma.

MATERIALS AND METHODS

A retrospective cohort of 22 patients who underwent 23 TARE procedures were selected. Patients were imaged in both cone-beam CT and angio-CT rooms as a part of their conventional treatment plan. Effective dose contributions from individual CT acquisitions as well as the cumulative dose contributions from procedural 3D imaging were evaluated. Angiography dose contributions were omitted. Cone-beam CT images were acquired on a C-arm Philips Allura system. Effective doses were evaluated by coupling previously published conversion factors (effective dose per dose-area product) to patient's dose-area product meter readings after the procedure. Angio-CT images were acquired on a hybrid Canon Infinix-i Aquilion PRIME system. Effective doses from angio-CT scans were estimated using Radimetrics. Comparisons of a single patient's dose differential between the 2 technologies were made.

RESULTS

The mean effective dose from a single CT scan was 6.42 mSv and 5.99 mSv in the cone-beam CT room and the angio-CT room, respectively (P = .3224), despite the greater field of view and average craniocaudal scan coverage in angio-CT. The mean effective dose summed across all CTs in a procedure was 12.89 mSv and 34.35 mSv in the cone-beam CT room and the angio-CT room, respectively (P = .0018).

CONCLUSIONS

The mean effective dose per CT scan is comparable between cone-beam CT and angio-CT when considered in direct comparison for a single patient.

Three Dimensional Visualisation of Endovascular Guidewires and Catheters Based on Laser Light instead of Fluoroscopy with Fiber Optic RealShape Technology: Preclinical Results

OBJECTIVE

Fiber Optic RealShape (FORS) is a new technology platform that enables real time three dimensional (3D) visualisation of endovascular guidewires and catheters, based on the concepts of fibre optic technology instead of fluoroscopy. Anatomical context is provided by means of co-registered prior anatomical imaging, such as digital subtraction angiography or computed tomography. This preclinical study assesses the safety and feasibility of FORS technology.

METHODS

Six physicians performed endovascular tasks in a phantom model and a porcine model using FORS enabled floppy guidewires, Cobra-2 catheters and Berenstein catheters. Each physician performed a set of predefined tasks in both models, including setup of the FORS system, device registration, and 12 aortic and peripheral target vessel cannulation tasks. The evaluation of the FORS system was based on (i) target vessel cannulation success; (ii) safety assessment; (iii) the accuracy of the FORS based device visualisation; and (iv) user experience.

RESULTS

Successful cannulation was achieved in 72 of the 72 tasks (100%) in the phantom model and in 70 of the 72 tasks (97%) in the porcine model. No safety issues were reported. The FORS based device visualisation had a median offset at the tip of 2.2 mm (interquartile range 1.2-3.8 mm). The users judged the FORS based device visualisation to be superior to conventional fluoroscopic imaging, while not affecting the mechanical properties (torquability, pushability) of the FORS enabled guidewire and catheters.

CONCLUSION

The combined outcomes of high cannulation success, positive user experience, adequate accuracy, and absence of safety issues demonstrate the safety and feasibility of the FORS system in a preclinical environment. FORS technology has great potential to improve device visualisation in endovascular interventions.

Validation of a New Method for 2D Fusion Imaging Registration in a System Prepared Only for 3D

Purpose: To validate a new 2D-3D registration method of fusion imaging during aortic repair in a system prepared only for 3D-3D registration and to compare radiation doses and accuracy. Materials and Methods: The study involved 189 patients, including 94 patients (median age 70 years; 85 men) who underwent abdominal endovascular aneurysm repair (EVAR) with 2D-3D fusion on an Artis zee imaging system and 95 EVAR patients (median age 70 years; 81 men) from a prior study who had 3D-3D registration done using cone beam computed tomography (CBCT). For the 2D-3D registration, an offline CBCT of the empty operating table was imported into the intraoperative dataset and superimposed on the preoperative computed tomography angiogram (CTA). Then 2 intraoperative single-frame 2D images of the skeleton were aligned with the patient's skeleton on the preoperative CTA to complete the registration process. A digital subtraction angiogram was done to correct any misalignment of the aortic CTA volume. Values are given as the median [interquartile range (IQR) Q1, Q3]. Results: The 2D-3D registration had an accuracy of 4.0 mm (IQR 3.0, 5.0) after bone matching compared with the final correction with DSA (78% within 5 mm). By applying the 2D-3D protocol the radiation exposure (dose area product) from the registration of the fusion image was significantly reduced compared with the 3D-3D registration [1.12 Gy∙cm² (IQR 0.41, 2.14) vs 43.4 Gy∙cm² (IQR 37.1, 49.0), respectively; p<0.001). Conclusion: The new 2D-3D registration protocol based on 2 single-frame images avoids an intraoperative CBCT and can be used for fusion imaging registration in a system originally designed for 3D-3D only. This 2D-3D registration protocol is accurate and leads to a significant reduction in radiation exposure.

Comparison of radiation dose and image quality between flat panel computed tomography and multidetector computed tomography in a hybrid CT-angiography suite

The purpose of this study was to compare, using the same radiation dose and image quality metrics, flat panel computed tomography (FPCT) to multidetector CT (MDCT) in interventional radiology. A single robotic angiography system with FPCT was compared to a single MDCT system, both installed in a hybrid CT-angiography laboratory and both operating under automatic exposure control. Radiation dose was measured on the central axis (D_c ) of a CT dosimetry phantom 30 cm in diameter and 60 cm in length using default protocols for FPCT and MDCT with the imaged length in MDCT matched to the field of view of FPCT. The noise power spectrum (NPS), modulation transfer function (MTF), and z-axis resolution were measured using the same phantom. Iodine contrast to noise ratio (CNR) was also measured. Radiation dose (D_c ) was 41%-69% lower in MDCT compared to FPCT when default protocols and automatic exposure control were used. While spatial resolution could generally be matched with appropriate choice of kernel in MDCT, MTF dropped more quickly at higher spatial frequency for MDCT than FPCT. Image noise was 49%-120% higher for MDCT compared to FPCT for comparable in-plane spatial resolution. Z-axis resolution was slightly better for MDCT than FPCT, while iodine CNR depended on protocol selection. Radiation dose was much lower for MDCT compared to FPCT, but image noise was much higher. Matching image noise in MDCT to FPCT would result in similar radiation doses. Iodine contrast depended on dose modulation settings for MDCT.

Intra-operative computed tomography in endovascular aneurysm repair

The study objective was to evaluate the ability of computed tomography (CT) to identify technical complications intra-operatively during endovascular aneurysm repair (EVAR). Frequency of complications seen by CT and their sequelae was compared with conventional completion angiography.

METHODS

We performed a systematic review that conformed to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. We considered studies reporting on the effectiveness of intra-operative CT during EVAR.

RESULTS

Our literature search yielded six studies that met our criteria for inclusion. In general, these showed intra-operative CT to be superior to completion angiogram at detecting intra-operative complications during EVAR. Despite concerns regarding irradiation, the use of intra-operative CT was found to expose patients to an overall lower radiation dose, since post-operative CT angiograms were no longer required. Moreover, no adverse effect on renal function has been demonstrated as a result of the increased intra-operative contrast usage when CT is used.

CONCLUSIONS

The current body of evidence suggests that intra-operative CT is superior to completion angiography at detecting clinically important EVAR complications and incurs a lower total radiation dose with no added risk of contrast-induced renal impairment. Further research directly comparing the two modalities in the same cohort is required to determine sensitivity for individual complications.