Implantable Pressure-Sensing Devices for Monitoring Abdominal Aortic Aneurysms in Post-Endovascular Aneurysm Repair.

Over the past two decades, there has been extensive research into surveillance methods for the post-endovascular repair of abdominal aortic aneurysms, highlighting the importance of these technologies in supplementing or even replacing conventional image-screening modalities. This review aims to provide an overview of the current status of alternative surveillance solutions for endovascular aneurysm repair, while also identifying potential aneurysm features that could be used to develop novel monitoring technologies. It offers a comprehensive review of these recent clinical advances, comparing new and standard clinical practices. After introducing the clinical understanding of abdominal aortic aneurysms and exploring current treatment procedures, the paper discusses the current surveillance methods for endovascular repair, contrasting them with recent pressure-sensing technologies. The literature on three commercial pressure-sensing devices for post-endovascular repair surveillance is analyzed. Various pre-clinical and clinical studies assessing the safety and efficacy of these devices are reviewed, providing a comparative summary of their outcomes. The review of the results from pre-clinical and clinical studies suggests a consistent trend of decreased blood pressure in the excluded aneurysm sac post-repair. However, despite successful pressure readings from the aneurysm sac, no strong link has been established to translate these measurements into the presence or absence of endoleaks. Furthermore, the results do not allow for a conclusive determination of ongoing aneurysm sac growth. Consequently, a strong clinical need persists for monitoring endoleaks and aneurysm growth following endovascular repair.

Xanthogranulomatous Inflammation of the Aortic Aneurysm Wall after Endovascular Aortic Repair for Abdominal Aortic Aneurysm / 日本心臓血管外科学会雑誌

A 77-year-old woman underwent endovascular abdominal aortic repair (EVAR) for an abdominal aortic aneurysm (AAA)．Five years after surgery, she visited the hospital with the chief complaint of a fever. Enhanced computed tomography (CT) showed enlargement of the AAA around the stent-graft and a mass, which was suspected to be an abscess, outside the aneurysm. A blood test revealed a high level of inflammatory response. The patient was diagnosed with infectious AAA. She received antibiotics; however, the inflammatory response did not completely improve. A second CT scan revealed that the suspected abscess had a spreading tendency. The patient was referred to our hospital for a highly suspected stent-graft infection. We performed Y-graft replacement using a rifampicin-immersed graft, and as much as possible of the wall around the aortic aneurysm was removed. The inflammatory response improved rapidly after the operation, and the patient was discharged 15 days later. According to the results of a pathological examination, a diagnosis of xanthogranulomatous inflammation and fibrosis was made. Here, we report a rare case of xanthogranulomatous inflammation of the aortic aneurysm wall after EVAR.

Dynamic, Time-Resolved Computed Tomography Angiography Technique to Characterize Aortic Endoleak Type, Inflow and Provide Guidance for Targeted Treatment.

PURPOSE: To illustrate dynamic, time-resolved CTA (d-CTA) imaging technique in characterizing aortic endoleak type/inflow using quantitative parameters and its value in providing image guidance for targeted treatment approach. TECHNIQUE: Dedicated endoleak protocol involved acquiring multiple time-resolved contrast enhanced scans using third-generation CT scanner (Somatom Force®, Siemens Healthineers). Parameters such as scan field of view (FOV), kV, number/timing of scans were customized based on patient's body-mass-index, timing bolus, and prior imaging findings. D-CTA image datasets were evaluated qualitatively and quantitatively using time-attenuation curves (TAC) analysis after motion correction using a dedicated software (syngo.via®, Siemens). D-CTA findings from 4 illustrative cases demonstrating type I, type II (inferior mesenteric and lumbar artery inflow), and type III endoleak were illustrated. TAC analysis with time to peak parameter enabled better characterization of endoleak type and inflow. During endoleak intervention, target vessels from d-CTA images were electronically annotated and overlaid on fluoroscopy using 2D-3D image fusion to provide image guidance for targeted treatment. CONCLUSION: D-CTA imaging with TAC analysis characterizes aortic endoleak type and inflow, in addition to providing image guidance for targeted endoleak treatment. Such dynamic, time-resolved imaging techniques may provide further insights into understanding aortic endoleak that remains an Achilles heel for endovascular aortic aneurysm repair.

Management of Postoperative Complications Following Endovascular Aortic Aneurysm Repair.

Endovascular aneurysm repair (EVAR) is a minimally invasive therapeutic approach to manage abdominal aortic pathologies (eg, aneurysm and dissection). EVAR was first introduced in 1991. In 1994, endovascular technique was also applied for thoracic aorta, thoracic endovascular aortic repair (TEVAR). In recent decades, EVAR has become an acceptable first-line treatment with 50% utilization rate across most practices, especially in high-risk patients. The safety profile of EVAR is comparable to the open approach, with superiority in terms of perioperative mortality and morbidity. This article summarizes the most common complications following EVAR/TEVAR and the most current treatment modalities across practices.

Editor's Choice - Detection of Late Complications After Endovascular Abdominal Aortic Aneurysm Repair and Implications for Follow up Based on Retrospective Assessment of a Two Centre Cohort.

OBJECTIVE: Endovascular aortic aneurysm repair (EVAR) is associated with the risk of late complications and mandates follow up. This retrospective study assessed post-EVAR complications in a two centre cohort. The study evaluated the rate of complications presenting with symptoms vs. those detected by imaging follow up. Additionally, the agreement between DUS and CTA in detecting complications was assessed in patients with both. METHODS: All EVAR patients from 1998 to 2012 in two centres were included. Complications were classified based on whether they were symptomatic or detected by imaging, as well as based on imaging detection modality (DUS or CTA). For patients who had undergone DUS and CTA within three months of each other, the kappa coefficient of agreement was assessed. RESULTS: Four hundred and fifty-four patients treated by EVAR were identified. The median follow up time was 5.2 (IQR 2.8-7.6) years. One hundred and eighteen patients (26%) developed 176 complications. One hundred and six (60.2%) of the complications were asymptomatic, and 70 (39.8%) were symptomatic. Two hundred and fifty-three patients had imaging with both modalities within three months of each other; the kappa coefficient for agreement between CTA and DUS for detecting clinically significant complications was 0.91. Regarding CTA as the standard modality, DUS had a sensitivity of 88.8% (95% CI 77.3-95.8%) and a specificity of 99.4% (95% CI 97.1-99.9%). Three of the complications missed by DUS were related to loss of proximal and distal seal, all occurring in patients with short sealing length on first post-operative CT scan. CONCLUSION: Approximately a quarter of the patients developed complications, the majority of which were asymptomatic, underlining the importance of adequate surveillance. There was good agreement between CTA and DUS in detecting complications. Clinically significant complications related to inadequate seal were missed by DUS, suggesting that CTA still plays an important role in EVAR surveillance.

Efficacy of volumetric analysis of aorta as surveillance tool after EVAR.

OBJECTIVE: Compared to the diameter measurement, volume measurement of the aneurysm can be an alternative option for accurate evaluation. This study was undertaken to analyze the relationship between the diameter and the volume measurement of the aorta after EVAR. METHODS: From January 2012 to December 2016, 82 patients underwent EVAR in our institution. The infrarenal aorta after EVAR was evaluated with regard to maximal aortic diameter (DMAX) and aortic volume. The relationship between the DMAX and the aortic volume measurement after EVAR were analyzed. RESULTS: The rate of enlargement of aortic volume with endoleak over time was 0.02 cm3/month. The rate of enlargement of DMAX with endoleak over time was 0.007 mm/month. The mean rate of enlargement of aortic volume was significantly different from the mean enlargement rate of DMAX (p = 0.02). A ≥12% of increase rate of aortic volume was equivalent to an increase of ≥5 mm in the DMAX after EVAR. Significantly more endoleak occurred in the DMAX-enlargement group than no-enlargement group (100% vs. 26.76%, p < 0.001). Significantly more patients need secondary intervention and treatment of endoleak in the DMAX-enlargement group (p = 0.02 and p < 0.001, respectively). Significantly more endoleak occurred in the aortic volume-enlargement group than no-enlargement group (90.91% vs. 16.67%, p < 0.001). Significantly more patients needed secondary intervention and treatment for endoleak in the aortic volume-enlargement group (p = 0.02 and p < 0.001, respectively). CONCLUSION: Volumetric analysis can predict successful EVAR more accurate than diameter measurement. A ≥12% increase in aortic volume was equivalent to a ≥5 mm increase in aortic diameter.

Duplex Ultrasound versus Computed Tomography for the Postoperative Follow-Up of Endovascular Abdominal Aortic Aneurysm Repair. Where Do We Stand Now?

In the last decade, endovascular aneurysm repair (EVAR) has rapidly developed to be the preferred method for infrarenal abdominal aortic aneurysm repair in patients with suitable anatomy. EVAR offers the advantage of lower perioperative mortality and morbidity but carries the cost of device-related complications such as endoleak, graft migration, graft thrombosis, and structural graft failure. These complications mandate a lifelong surveillance of EVAR patients and their endografts. The purpose of this study is to review and evaluate the safety of color-duplex ultrasound (CDU) as compared with computed tomography (CT), based on the current literature, for post-EVAR surveillance. The post-EVAR follow-up modalities, CDU versus CT, are evaluated questioning three parameters: (1) accuracy of aneurysm size, (2) detection and classification of endoleaks, and (3) detection of stent-graft deformation. Studies comparing CDU with CT scan for investigation of post-EVAR complications have produced mixed results. Further and long-term research is needed to evaluate the efficacy of CDU versus CT, before CDU can be recommended as the primary imaging modality for EVAR surveillance, in place of CT for stable aneurysms.