Renal duplex ultrasound findings in fenestrated endovascular aortic repair for juxtarenal aortic aneurysms

Effect of fenestration configuration on renal artery outcomes during fenestrated-branched endovascular aortic repair

OBJECTIVE

The aim of this study was to evaluate the effect of fenestration configuration and fenestration gap on renal artery outcomes during fenestrated-branched endovascular aortic repair (F/BEVAR).

METHODS

A retrospective multicenter analysis was performed, including patients with complex aortic aneurysms treated with F/BEVAR that incorporated at least one small fenestration to a renal artery. The renal fenestrations were divided into groups 1 (8 × 6 mm) and 2 (6 × 6 mm). Primary patency, target vessel instability (TVI), freedom from secondary interventions (SIs), occurrence of type IIIc endoleak, all related to the renal arteries, were analyzed at 30-day, 1-year, and 5-year landmarks. The fenestration gap (FG) distance was analyzed as a modifier, and clustering was addressed at the patient level.

RESULTS

A total of 796 patients were included in this study, 71.7% male, with a mean age of 73.3 ± 8.1 years. The mean follow-up was 30.0 ± 20.6 months. Of the 1474 small renal fenestrations analyzed, 47.6% were 8 × 6 mm, and 52.4% were 6 × 6 mm. At the 30-day landmark, primary patency (99.9% vs 98.0%; P value < .001 for groups 1 and 2, respectively), freedom from TVI (99.6% vs 97.1%; P value < .001 for groups 1 and 2, respectively), and freedom from SI (99.8% vs 98.4%; P value = .022 for groups 1 and 2, respectively) were higher in 8 × 6 compared with 6 × 6 fenestrations, and the incidence of acute kidney injury was similar across the groups (92.6% vs 92.7%; P value = .953 for groups 1 and 2 respectively). The primary patency at 1 and 5 years was higher in 8 × 6 fenestrations (1-year: 98.8% vs 96.9%; 5-year: 97.8% vs 95.7%, for groups 1 and 2, respectively, P values = .010 and .021 for 1 and 5 year comparisons, respectively). The freedom from SIs was significantly higher among 6 × 6 fenestrations at 5 years (93.1% vs 96.4%, for groups 1 and 2, respectively, P value = .007). The groups were equally as likely to experience a type Ic endoleak (1.3% and 1.6% for 8 × 6 and 6 × 6mm fenestrations, respectively, P = .689). The 6 × 6 fenestrations were associated with higher risk of kidney function deterioration (17.8%) when compared with 8 × 6 fenestrations (7.6%) at 5 years (P < .001). The risk of type IIIc endoleak was significantly higher among 8 × 6 fenestrations at 5 years (4.9% and 2% for 8 × 6 and 6 × 6 mm fenestrations, respectively; P = .005). A FG ≥5 mm negatively impacted the cumulative 5-year freedom from TVI (group 1: FG ≥5 mm = 0.714, FG <5 mm = 0.857; P < .001; group 2: FG ≥5 mm = 0.761, FG <5 mm = 0.929; P < .001) and the cumulative 5-year freedom from type IIIc endoleak (group 1: FG ≥5 mm = 0.759, FG <5 mm = 0.921; P = .034; group 2: FG ≥5 mm = 0.853, FG <5 mm = 0.979; P < .001) in both groups and the cumulative 5-year patency in group 2 (group 1: FG ≥5 mm = 0.963, FG <5 mm = 0.948; P = .572; group 2: FG ≥5 mm = 0.905, FG <5 mm = 0.938; P = .036).

CONCLUSIONS

Fenestration configuration for the renal arteries impacts outcomes. The 8 × 6 small fenestrations have better patency at 30 days, 1 year, and 5 years, whereas 6 × 6 small fenestrations are associated with lower rates of SIs, primarily due to a lower incidence of type IIIc endoleaks. FG ≥5 mm at the level of the renal arteries significantly impacts the freedom from TVI, freedom from type IIIc endoleak, and 5-year patency independently of the fenestration size or vessel diameter.

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.

Structural requirement of RARγ agonism through computational aspects

CONTEXT

RARγ is a therapeutic target for many skin diseases and has potential in cancer treatment. In the current study, we put forward a comprehensive structure-activity relationship study of third and fourth generations of RARγ agonists, addressing multiple crystal structures of RARγ complexes and approved drugs. Adapalene and Trifarotene, through hybrid strategies including protein contacts Atlas analysis, molecular docking, dynamics simulations, MM-GBSA, ASM, and pharmacophore modeling. Our result revealed crucial amino acids Arg267, Ser278, Phe288, Phe230, Met272, Leu271, and Leu268 within the RARγ pocket, as well as pharmacophore features such as two hydrophobic groups, two aromatic rings, and negative ionic features, which are essential for the binding of RARγ agonists. Based on this study, the binding mechanism of RARγ agonists was elucidated, which will be helpful for the rational design of new RARγ agonists for skin diseases and cancer treatment.

METHODS

In this study, Schrödinger suite 2021-2 with OPLS_4 force field, Discovery Studio program 3.0, LigandScout 4.3, and PyMOL are utilized in the investigation.

Duplex Ultrasound Can Successfully Identify Endoleaks and Renovisceral Stent Patency in Patients Undergoing Complex Endovascular Aneurysm Repair

Efficacy of duplex ultrasound (DU) surveillance of complex EVAR such as FEVAR and ChEVAR has not been studied. All patients undergoing FEVAR or ChEVAR at a single multihospital institution were retrospectively reviewed. Postoperative surveillance included DU at 1 month and CTA at 3 months. 82 patients met inclusion criteria including 39 (47.6%) ChEVAR and 43 (52.4%) FEVAR cases. DU identified endoleak with aneurysm sac enlargement in 3 cases requiring reintervention. CTA at 3 months detected 2 new endoleaks without growth and 1 renal artery stent occlusion. Replacement of initial postoperative imaging with DU did not result in any missed endoleaks, deaths, ruptures, or branch occlusions.

Renal Stent Complications and Impact on Renal Function after Standard Fenestrated Endovascular Aneurysm Repair

BACKGROUND

To report renal outcomes including long-term patency, secondary interventions, and related renal function after fenestrated endovascular aortic repair (fEVAR).

METHODS

Single-center retrospective review of patients undergoing fEVAR between 2012 and 2018 using the Cook ZFEN device. Renal stent complications, defined as any stenosis, occlusion, kink, renal stent-related endoleak, and reinterventions were tabulated. Estimated glomerular filtration rate (eGFR) was estimated using the Modification of Diet in Renal Disease formula.

RESULTS

During the study period, 114 patients underwent elective fEVAR. Of 329 total target vessels, 193 renal arteries were stented (133 Atrium iCAST, 60 Gore VBX). Technical success was achieved in 97.4%, and the mean follow-up was 23.3 months. Seventeen renal complications occurred in 14 patients (12.3%), including 4 occlusions, 9 stenosis, 3 dislocations, and 1 type III endoleak. All stent complications underwent endovascular reintervention with a median hospital stay of 1 day (0-10) and a technical success of 94.2%. One patient suffered renal hemorrhage that warranted embolization. Patients with occlusion were treated the day of diagnosis, and mean time from diagnosis to intervention for stenosis was 21.5 days. Estimated primary patency was 92.1 % and 81.5% at 24 and 48 months, respectively. On multivariate analysis, larger native renal artery diameter was the only independent protective factor against patency loss (HR 0.23 (0.09-0.59)). Secondary patency at latest follow-up was 99.4%. Mean eGFR was not significantly different at latest follow-up between patients with renal complications versus those without (43.75 vs. 55.58 mL/min/1.73 m², P = 0.09). Comparing patients with and without renal stent complications, 81.4% and 72.7% of patients had stable or improved renal disease by chronic kidney disease staging compared with baseline (P = 0.51).

CONCLUSIONS

fEVAR is a durable option for the treatment of juxtarenal aortic aneurysms and is associated with excellent secondary patency. Renal stent complications have no significant impact on renal function, but smaller native renal arteries are at higher risk of stent-graft complications.

Thoracic Aortic Dilation after Endovascular Repair of Blunt Traumatic Aortic Injury

BACKGROUND

Thoracic endovascular aneurysm repair (TEVAR) has become the current standard of care for emergent treatment of traumatic blunt thoracic aortic injuries (BTAI). Although aortic dilation (AD) of the infrarenal neck after EVAR for aortic aneurysms has been studied, changes in aortic diameter after TEVAR for BTAI is not well understood. This study aims to characterize changes in thoracic aortic diameter after stent-graft placement in the setting of nonaneurysmal traumatic aortic injury.

METHODS

A single-center, retrospective review was performed involving patients presenting with BTAI treated with TEVAR. Only patients with at least 12 months follow-up were included. Aortic diameter, defined as the outer-to-outer diameter on 3D center-line imaging, was measured at six locations along the proximal and mid thoracic aorta. The first postoperative CT (≤1 month) served as a baseline from which interval measurements were compared.

RESULTS

Twenty patients with BTAI treated from 2011 to 2017 had adequate imaging available for review and were included in this study cohort. Median follow-up time was 46.8 (12-80, range) months. At the latest follow-up, AD occurred at all measured locations within the endograft, starting from the proximal graft edge (0.62 ± 0.69 mm, P = 0.027) to the distal graft edge (1.21 ± 1.28 mm, P = 0.003). AD was most pronounced in the distal graft segment 2 cm proximal to the distal graft edge, with a mean AD of 1.32 ± 1.59 mm (+5.3%, P < 0.001). At this location, AD was found to increase in a linear manner with an estimated rate of 0.67 ± 0.20 mm/year (P = 0.006). The native aorta proximal and distal to the endograft was not found to significantly dilate during follow-up (P = 0.280-0.897). Seventy percent of the patients were found to have AD >5%. The amount of AD was not found to be associated with either graft oversizing (P = 0.151) or age (P = 0.340). There were no cases of graft migration, erosion, or endoleak.

CONCLUSIONS

AD is a common benign finding after TEVAR for BTAI. AD is most pronounced at the near the distal end of the stent graft. In late-term follow-up, there are no known associated complications related to AD.

Duplex ultrasound follow-up after fenestrated and branched endovascular aneurysm repair (FEVAR and BEVAR)

Endovascular aneurysm repair (EVAR) is now the predominant method for treatment of infrarenal abdominal aortic aneurysms. Although EVAR has numerous advantages over standard open surgical repair, it also exposes patients to risks such as aneurysm sac enlargement, endoleaks, and graft migration, which make surveillance or follow-up mandatory. Fenestrated (FEVAR) and branched (BEVAR) endografts have extended the application of EVAR to juxtarenal, pararenal/paravisceral, and thoracoabdominal aneurysms, with some complex aneurysms requiring combined approaches (F-BEVAR). Duplex ultrasound has been recommended as an alternative to frequent computed tomography imaging for EVAR follow-up when it can provide the clinically necessary information. The major components of a post-EVAR duplex examination include measurement of aortic aneurysm sac size, assessment for endoleak, and evaluation of the endograft for patency and integrity. The duplex protocol for EVAR follow-up can be extended for follow-up after FEVAR, BEVAR, and F-BEVAR, with additional attention to the device components associated with fenestrations and branches. At the University of Washington, the physician-modified endovascular graft approach has been used for FEVAR. During these procedures, covered stents are placed in the renal arteries through fenestrations and the superior mesenteric artery is perfused through a fenestration, but typically remains unstented. Duplex scanning of the renal and mesenteric arteries has been performed preoperatively and at 30 days, 6 months, 1 year, and annually. In a review of patients having covered stents placed in non-stenotic renal arteries during FEVAR, both peak systolic velocity and the renal to aortic velocity ratio remained below the standard significant stenosis threshold in most patients. The duplex velocity criteria for stenosis in native renal arteries appeared to overestimate the severity of stenosis in renal artery covered stents. The unstented superior mesenteric artery remained widely patent in the presence of fenestrations or crossing struts and was not associated with endoleaks. Duplex ultrasound protocols for follow-up after FEVAR, BEVAR, and F-BEVAR can be based on those that have been established for standard EVAR, along with assessment of fenestrations and branches, as well as patency of the renal and mesenteric arteries.

Geometric and hemodynamic analysis of fenestrated and multibranched aortic endografts

OBJECTIVE

The objective of this study was to determine the influence of hemodynamic force on the development of type III endoleak and branch thrombosis after complex endovascular thoracoabdominal aortic aneurysm repair.

METHODS

Patients with thoracoabdominal aortic aneurysm, within surgical range, treated with a fenestrated or branched endovascular aneurysm repair from 2014 to 2018 and with 3-month control computed tomography angiography were selected. Demographic variables, aneurysm anatomy, and endograft conformation were analyzed retrospectively from a prospective registry. The hemodynamic force was calculated using the mass and momentum conservation equations.

RESULTS

Twenty-eight patients were included; the mean follow-up period was 24.7 ± 19.3 months. There were 102 abdominal vessels successfully catheterized (19 celiac arteries, 29 superior mesenteric arteries, 27 right renal arteries, 26 left renal arteries, and 1 polar renal artery). The rate of type III endoleak was 11.5% (n = 12); six cases were associated with branches that received two stents (P < .001). A higher rate of endoleak was observed with wider stents (8.50 ± 1.0 mm vs 7.17 ± 1.3 mm; P = .001) but not with longer stents (P = .530). All cases of type III endoleak affected visceral arteries (eight celiac arteries and four superior mesenteric arteries). The freedom from type III endoleak at 24 months was 86%. The rate of thrombosis was 5.9% (n = 6). A higher rate of thrombosis was observed in smaller vessels (5.00 ± 1.3 mm vs 7.16 ± 1.8 mm; P = .001), with higher stent oversizing (36.87% ± 23.6% vs 5.52% ± 15.0%; P < .001), and with a higher angle of curvature (124.33 ± 86.1 degrees vs 57.71 ± 27.9 degrees; P < .001). All cases of thrombosis were related to renal arteries (two left renal arteries, two right renal arteries, and two polar renal arteries). The freedom from thrombosis at 24 months was 92%. The area under the curve for the angle of curvature was 0.802 (95% confidence interval, 0.661-0.943; P = .013), and the cutoff point was established at 59.5 degrees (sensitivity, 100%; specificity, 60.4%). The receiver operating characteristic curve for the stent oversize showed an area under the curve of 0.903 (95% confidence interval, 0.821-0.984; P = .001), and the cutoff point was 14.5% (sensitivity, 100%; specificity, 77.1%). A higher hemodynamic force was associated with thrombosis (23.35 × 10^-3 N ± 18.7 × 10^-3 N vs 12.31 × 10^-3 N ± 6.8 × 10^-3 N; P = .001) but not with endoleak (P = .796). The freedom from endoleak and thrombosis at 24 months was 86% and 90%, respectively.

CONCLUSIONS

Longer stents should be preferred to avoid type III endoleak. A higher angle of curvature leads to a higher hemodynamic force that results in a higher rate of thrombosis. Accordingly, we recommend maintaining the angle of curvature under 59.9 degrees. Small vessels and excessive stent oversizing entail a higher risk of thrombosis; as such, we advise a maximum stent oversize of 14.5%. Renal arteries are more susceptible to thrombosis, whereas visceral arteries are more prone to endoleak.

Duplex ultrasound surveillance of renal branch grafts after fenestrated endovascular aneurysm repair

OBJECTIVE

The use of duplex ultrasound (DUS) examinations for surveillance after fenestrated endovascular aneurysm repair (FEVAR) is not well-studied. Our objective was to further characterize normal and abnormal duplex findings in renal branch grafts after FEVAR.

METHODS

We retrospectively reviewed a single-center experience involving consecutive patients treated with Cook ZFEN devices between 2012 and 2017. Postoperative imaging consisted of a computed tomography (CT) scan at 1 month, 6 months, 1 year, and annually thereafter. As experienced progressed, DUS examination with or without concurrent CT scans were obtained in a nonstandardized protocol, particularly for patients with decreased renal function. Renal patency loss was defined as occlusion or stenosis of greater than 50% evaluated on 3-day renal artery center-line imaging.

RESULTS

A total of 116 patients were treated with FEVAR, of which 60 (51.7%) had concurrent CT and renal DUS images available for review. Six patients (10%) had limited ultrasound studies owing to bowel gas and were excluded. The study cohort therefore included 54 patients receiving of 94 renal fenestrated stents with a mean follow-up of 23 months. Twelve cases of renal patency loss in 10 patients (9 stenoses, 3 occlusions) were found on CT scanning, 11 (91.6%) of which had concurrent abnormalities found on ultrasound examination. Stents with compression at the junction of the main body exhibited significantly elevated mean Peak systolic velocities (PSV) compared with nonstenosed stents (349.2 cm/s vs 115.3 cm/s; P = .003). Stenosis in the most proximal portion of the stent (ie, within the main body) showed no difference in proximal PSV (86.0 cm/s vs 131.9 cm/s; P = .257); however, dampened PSV showed significant differences in the mid (17.5 cm/s vs 109.9 cm/s; P = .027) and distal (19.0 cm/s vs 78.3 cm/s; P = .028) segments compared with nonstenosed stents. All occluded stents demonstrated no flow detection. Proximal PSV served as a strong classifier for junctional stenosis (area under the curve, 0.98). A combined criterion of proximal PSV of greater than 215 cm/s or distal PSV of less than 25 cm/s resulted in a sensitivity of 91.6% and specificity of 85.3% for detecting patency loss. All stents that were compromised underwent successful secondary reintervention and restoration of patency.

CONCLUSIONS

DUS imaging is a clinically useful modality for surveillance of renal branch grafts after FEVAR. Patterns of segmental velocity elevation (proximal PSV, >215 cm/s) and dampening in the distal renal indicate potential hemodynamic compromise and should prompt more aggressive workup or imaging and likely be considered for secondary intervention.

Accuracy of implementing principles of fusion imaging in the follow up and surveillance of complex aneurysm repair

Fusion imaging is standard for the endovascular treatment of complex aortic aneurysms, but its role in follow up has not been explored. A critical issue is renal function deterioration over time. Renal volume has been used as a marker of renal impairment; however, it is not reproducible and remains a complex and resource-intensive procedure. The aim of this study is to determine the accuracy of a fusion-based software to automatically calculate the renal volume changes during follow up. In this study, computerized tomography (CT) scans of 16 patients who underwent complex aortic endovascular repair were analysed. Preoperative, 1-month and 1-year follow-up CT scans have been analysed using a conventional approach of semi-automatic segmentation, and a second approach with automatic segmentation. For each kidney and at each time point the percentage of change in renal volume was calculated using both techniques. After review, volume assessment was feasible for all CT scans. For the left kidney, the intraclass correlation coefficient (ICC) was 0.794 and 0.877 at 1 month and 1 year, respectively. For the right side, the ICC was 0.817 at 1 month and 0.966 at 1 year. The automated technique reliably detected a decrease in renal volume for the eight patients with occluded renal arteries during follow up. This is the first report of a fusion-based algorithm to detect changes in renal volume during postoperative surveillance using an automated process. Using this technique, the standardized assessment of renal volume could be implemented with greater ease and reproducibility and serve as a warning of potential renal impairment.