Endovascular Preservation of Segmental Arteries during Treatment of Thoracoabdominal Aortic Aneurysms with Fenestrated/Branched Stent Grafts: Feasibility and Outcomes.

PURPOSE: To evaluate the technical success, feasibility, and outcomes of endovascular preservation of segmental arteries (SAs) during fenestrated/branched endovascular aortic repair (F/B-EVAR). MATERIALS AND METHODS: A multicenter, retrospective study was conducted in consecutive patients treated with F/B-EVAR and a branch or fenestration for SA preservation. Eleven patients (median age, 57 years; range, 45-73 years; 7 men) were included. RESULTS: Twelve SAs were preserved. Stent grafts were custom made with fenestrations, branches, or a combination of both in 1, 2, and 5 patients, respectively. A t-Branch stent graft was used in 2 patients, and a physician-modified thoracic stent graft with a branch was used in 1 patient. Eight branches and 4 fenestrations were used for the preservation of 12 SAs. Four fenestrations and 1 branch for the SAs were not bridged and were left for perfusion of the corresponding SAs. Technical success was achieved in 10 of 11 (91%) patients. No early mortality occurred. Early morbidities included renal insufficiency without dialysis in 1 patient and partially delayed paraplegia in 1 patient. Before discharge, computed tomography angiography (CTA) showed patency of all the SAs. The median follow-up duration was 30 months (range, 10-88 months). Late death occurred in 1 patient. Two SAs were occluded in 1 patient with 2 unstented fenestrations, as determined using 1-year follow-up CTA. This patient did not develop spinal cord ischemia (SCI). Other SAs remained patent during follow-up. One patient with a type IIIc endoleak was treated by relining of bridging stents. CONCLUSIONS: Endovascular preservation of SAs with F/B-EVAR for thoracoabdominal aortic aneurysm is feasible and safe in select patients and may add to preventive measures for SCI.

Evaluation of a hybrid pipeline for automated segmentation of solid lesions based on mathematical algorithms and deep learning.

We evaluate the accuracy of an original hybrid segmentation pipeline, combining variational and deep learning methods, in the segmentation of CT scans of stented aortic aneurysms, abdominal organs and brain lesions. The hybrid pipeline is trained on 50 aortic CT scans and tested on 10. Additionally, we trained and tested the hybrid pipeline on publicly available datasets of CT scans of abdominal organs and MR scans of brain tumours. We tested the accuracy of the hybrid pipeline against a gold standard (manual segmentation) and compared its performance to that of a standard automated segmentation method with commonly used metrics, including the DICE and JACCARD and volumetric similarity (VS) coefficients, and the Hausdorff Distance (HD). Results. The hybrid pipeline produced very accurate segmentations of the aorta, with mean DICE, JACCARD and VS coefficients of: 0.909, 0.837 and 0.972 in thrombus segmentation and 0.937, 0.884 and 0.970 for stent and lumen segmentation. It consistently outperformed the standard automated method. Similar results were observed when the hybrid pipeline was trained and tested on publicly available datasets, with mean DICE scores of: 0.832 on brain tumour segmentation, and 0.894/0.841/0.853/0.847/0.941 on left kidney/right kidney/spleen/aorta/liver organ segmentation.

Characterising the incidence and mode of visceral stent failure after fenestrated endovascular aneurysm repair (FEVAR).

BACKGROUND: In FEVAR, visceral stents provide continuity and maintain perfusion between the main body of the stent and the respective visceral artery. The aim of this study was to characterise the incidence and mode of visceral stent failure (type Ic endoleak, type IIIa endoleak, stenosis/kink, fracture, crush and occlusion) after FEVAR in a large cohort of patients at a high-volume centre. METHODS: A retrospective review of visceral stents placed during FEVAR over 15 years (February 2003-December 2018) was performed. Kaplan-Meier analyses of freedom from visceral stent-related complications were performed. The outcomes between graft configurations of varying complexity were compared, as were the outcomes of different stent types and different visceral vessels. RESULTS: Visceral stent complications occurred in 47/236 patients (19.9%) and 54/653 stents (8.3%). Median follow up was 3.7 years (IQR 1.7-5.3 years). There was no difference in visceral stent complication rate between renal, SMA and coeliac arteries. Visceral stent complications were more frequent in more complex grafts compared to less complex grafts. Visceral stent complications were more frequent in uncovered stents compared to covered stents. Visceral stent-related endoleaks (type Ic and type IIIa) occurred exclusively around renal artery stents. The most common modes of failure with SMA stents were kinking and fracture, whereas with coeliac artery stents it was external crush. CONCLUSION: Visceral stent complications after FEVAR are common and merit continued and close long-term surveillance. The mode of visceral stent failure varies across the vessels in which the stents are located.

Aneurysm Growth After Endovascular Sealing of Abdominal Aortic Aneurysms (EVAS) with the Nellix Endoprosthesis.

OBJECTIVE: The aim of this study was to measure the incidence of post endovascular aneurysm sealing (EVAS) abdominal aortic aneurysm (AAA) growth, and its association with stent migration, in a cohort of patients with differing compliance to old and new Instructions For Use (IFU). METHODS: A retrospective single centre study was conducted to review the computed tomography (CT) and clinical data of elective, infrarenal EVAS cases, performed as a primary intervention, between December 2013 and March 2018. All included patients had a baseline post-operative CT scan at one month and at least one year follow up. The primary outcome measure was the incidence of AAA growth and its association with stent migration. AAA growth was defined as a ≥5% increase in aortic volume between the lowermost renal artery and the aortic bifurcation post EVAS at any time during follow up, in comparison to the baseline CT scan. Migration was defined according to the ESVS guidelines, as > 10 mm downward movement of either Nellix stent frame in the proximal zone. RESULTS: Seventy-six patients were eligible for inclusion in the study (mean age 76 ± 7.4 years; 58 men). AAA growth was identified in 50 of 76 patients (66%); adherence to IFU did not affect its incidence (mean growth within IFU-2016 compliant cohort vs. non-compliant: 16% vs. 13%, p = .33). Over time, the incidence of AAA growth increased, from 32% at one year to 100% at four years. AAA growth by volume was progressive (p < .001), as its extent increased over time. Migration was detected in 16 patients and there was a statistically significant association with AAA growth (13 patients displayed migration and AAA growth, p = .036). CONCLUSION: Patients treated with EVAS are prone to AAA growth, irrespective of whether their aortic anatomy is IFU compliant. AAA growth by volume is associated with stent migration. Clinicians should continue close surveillance post EVAS, regardless of whether patients are treated within IFU.

Observational study on the incidence of nephrogenic systemic fibrosis in patients with renal impairment following gadoterate meglumine administration: the NSsaFe study.

BACKGROUND: Nephrogenic systemic fibrosis (NSF) is a rare life-threatening condition strongly associated with the administration of gadolinium-based contrast agents in patients with severe or endstage renal impairment. PURPOSE: To prospectively determine the incidence of NSF in patients with renal impairment after administration of gadoterate meglumine. STUDY TYPE: Prospective. POPULATION: In all, 540 patients with moderate, severe, or endstage renal impairment, scheduled to undergo a routine contrast-enhanced MRI with gadoterate meglumine. Mean age was 69.7 ± 12.7 years (range: 21-95) with 58.4% of males. FIELD STRENGTH/SEQUENCE: 1.5T or 3.0T, sequence according to each site practice. ASSESSMENT: Medical history, indication(s) for current MRI and adverse events were recorded for each patient. Patients were followed up over 2 years after administration with three visits separated by at least 3 months to detect any signs/symptoms suggestive of NSF. STATISTICAL TESTS: Descriptive. RESULTS: Renal impairment was graded as moderate for 69.4% of patients, severe for 16.0% and endstage for 12.1%; 2.6% had undergone a kidney transplant. Estimated glomerular filtration rate ranged from 4 to 59 mL/min/1.73 m2 except one value of 74 mL/min/1.73 m2 in a patient with kidney transplant. Central nervous system exploration was the main MRI indication (34.7%) and mean dose injected was 0.22 ± 0.09 mL/kg. Overall, 446 patients (82.6%) attended at least one follow-up visit and completed the NSF questionnaire and 329 (60.9%) attended the 2-year visit. No suspicion of NSF was reported in all 446 patients, including 119 patients with severe or endstage renal impairment. No deaths and no adverse events were reported during the MRI examination and the usual period of follow-up after gadoterate meglumine administration. DATA CONCLUSION: No cases of NSF were observed in the 446 patients with moderate to endstage renal impairment followed up over a maximum of 2 years after injection of gadoterate meglumine. LEVEL OF EVIDENCE: 2 Technical Efficacy Stage: 4 J. Magn. Reson. Imaging 2020;51:607-614.

Meta-analysis of the accuracy of contrast-enhanced ultrasound for the detection of endoleak after endovascular aneurysm repair.

OBJECTIVE: The purpose of this systematic review and meta-analysis was to investigate the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) for detection of endoleak after endovascular aneurysm repair (EVAR). METHODS: We searched electronic bibliographic databases for original articles comparing concurrent CEUS and computed tomography angiography for detection of endoleak after EVAR. We assessed the methodologic quality of the studies with the Quality Assessment of Diagnostic Accuracy Studies-2 tool. We constructed 2 × 2 contingency tables for all selected studies including true-positive, false-positive, false-negative, and true-negative results for all endoleaks and for type I and type III endoleaks. We used a mixed-effects logistic regression model to estimate summary sensitivity and specificity. We developed hierarchical summary receiver operating characteristic curves and calculated the area under the curve (AUC). RESULTS: We identified 26 studies reporting a total of 2638 paired scans in 2217 patients. The major risk of bias of the selected studies pertained to blinding for the index test and the reference standard. The pooled sensitivity and specificity of CEUS for all endoleaks were 0.94 (95% confidence interval [CI], 0.89-0.97) and 0.93 (95% CI, 0.89-0.96), respectively. The AUC was 0.98 (95% CI, 0.93-0.99). The summary estimate of sensitivity and specificity for type I and type III endoleaks was 0.97 (95% CI, 0.8-1.00) and 1.00 (95% CI, 0.99-1.00), respectively. The AUC was 1.00 (95% CI, 0.99-1.00). CONCLUSIONS: CEUS has a high sensitivity and specificity in the detection of endoleaks after EVAR. CEUS is a useful tool in EVAR surveillance.

Stent Frame Movement Following Endovascular Aneurysm Sealing in the Abdominal Aorta.

PURPOSE: To investigate the incidence and extent of stent frame movement after endovascular aneurysm sealing (EVAS) in the abdominal aorta and its relationships to aneurysm growth and the instructions for use (IFU) of the Nellix endograft. METHODS: A retrospective single-center study was conducted to review the clinical data and computed tomography (CT) images of 75 patients (mean age 76±7.6 years; 57 men) who underwent infrarenal EVAS and had a minimum 1-year follow-up. The first postoperative CT scan at 1 month and the subsequent scans were used to measure the distances between the proximal end of the stent frames and a reference visceral vessel using a previously validated technique. Device migration was based on the Society of Vascular Surgery definition of >10-mm downward movement of either Nellix stent frame in the proximal landing zone; a more conservative proximal displacement measure (downward movement ⩾4 mm) was also recorded. Patients were categorized according to adherence to the old (2013) or new (2016) Nellix IFU. Aneurysm diameter was measured for each scan; a change ⩾5 mm was deemed indicative of aneurysm growth. RESULTS: Over a median follow-up of 24 months (range 12-48), proximal displacement ⩾4 mm occurred in 42 (56%) patients and migration >10 mm in 16 (21%), with similar incidences in the right and left stent frames. Proximal displacement was significantly more frequent among patients whose anatomy did not conform to any IFU (p=0.025). Presence of aneurysm growth ⩾5 mm was observed in 14 (19%) patients and was significantly associated with proximal displacement ⩾4 mm (p=0.03). CONCLUSION: Infrarenal EVAS may be complicated by proximal displacement and migration, particularly when performed outside the IFU. The definition of migration used for endovascular aneurysm repair may be inappropriate for EVAS; a new consensus on definition and measurement technique is necessary.

Endovascular Aneurysm Sealing (EVAS) Alone or in Combination with Chimney Grafts (chEVAS) for Treating Complications of Previous Endovascular Aneurysm Repair (EVAR) Procedures.

OBJECTIVE: Late complications after previous endovascular aneurysm repair (EVAR) procedures include type I/III endoleaks causing aneurysm growth and rupture. We reviewed our results from the management of such complications with endovascular aneurysm sealing (EVAS) techniques. METHODS: Analysis of our prospectively maintained aneurysm database was performed (December 2013-May 2017). Primary outcomes were: (1) success of the procedure in excluding the primary complication, (2) perioperative mortality, (3) post-operative complications and (4) survival. RESULTS: Ten consecutive patients were treated for complications of EVAR procedures performed 2-12 years previously. All patients underwent EVAS with/without chimney grafts for 6 type Ia,1 type IIIb and 3 undetermined (but presumed type IIIb) endoleaks. Overall, 19 Nellix® devices were used. The technical success with type Ia endoleaks was 100%. All sealed using proximal extension through chimney EVAS with 1 target vessel loss. There were no perioperative deaths. All but 1 type Ia endoleak remained eliminated at follow-up (range 2-29 months) as did the proven type IIIb endoleak. Two of the 3 undetermined endoleaks demonstrated continued sac expansion requiring surgical exploration by laparotomy, during which type II endoleaks were identified. CONCLUSIONS: EVAS provides effective short-term treatment of type Ia/IIIb endoleaks after EVAR. However, late complications may occur due to disease progression. LEVEL OF EVIDENCE: Level 4, case series.

Temporal Changes in Intraluminal Thrombus Volume Within Abdominal Aortic Aneurysms: Implications for Planning Endovascular Aneurysm Sealing.

PURPOSE: To explore whether or not there are temporal changes in the abdominal aortic aneurysm (AAA) and intraluminal thrombus (ILT) volumes between planning and implantation of the endovascular aneurysm sealing (EVAS) device and how these changes influence lumen volume. METHODS: A retrospective review was conducted of 51 AAA patients (mean age 76±7.1 years; 36 men) in whom 2 serial preoperative computed tomography angiograms (CTAs) had been performed within 1 to 18 months before fenestrated endovascular repair. The 2 preoperative CTAs were analyzed to identify changes in total sac, ILT, and lumen volumes. RESULTS: Over a median 7.0 months (interquartile range 4, 10), 46 (90%) of 51 AAAs increased in volume between the 2 CTAs. ILT volume increased in 44 aneurysms. In contrast, lumen volume increased in 31 and decreased in 20 AAAs. There was a strong correlation between changes in AAA volume and ILT volume (rs=0.859, p<0.001), which remained significant after adjustment for initial volumes (rs=0.815; p<0.001). There was no correlation between the time interval separating the 2 CTAs and changes in AAA volume (rs=0.115; p=0.421), changes in ILT volume (rs=0.084; p=0.599), or changes in lumen volume (rs=0.060; p=0.676). The AAA growth rate (defined as the change in AAA size/days between CTAs) showed a weak correlation with ILT volume (rs=0.272, p=0.054), which disappeared after adjustment for initial AAA size (rs=-0.002, p=0.991). Between the 2 CTAs, 12 aneurysms crossed the new <1.4 Nellix maximum aorta/lumen diameter ratio. CONCLUSION: As AAAs grow, the increase in aortic volume is largely occupied by additional ILT formation, with minimal change in lumen volume. These changes may alter the suitability of the aneurysm for the Nellix device and could have implications for EVAS planning and device deployment.

Anatomical Applicability of Endovascular Aneurysm Sealing Techniques in a Consecutive Cohort of Fenestrated Endovascular Aneurysm Repairs.

PURPOSE: To determine how many endovascular aneurysm sealing (EVAS) procedures with/without off-label use of chimneys (ChEVAS) could have been performed in a cohort of patients who had undergone fenestrated endovascular aneurysm repair (FEVAR). METHODS: Sixty patients (median age 76.3 years; 54 men) who underwent FEVAR in our institution between 2013 and 2015 were selected for the study. The median aneurysm diameter was 62.0 mm (interquartile range 59.3, 69.0). Preoperative computed tomography angiograms (CTA) were anonymized and sent to 2 physicians with experience of more than 40 ChEVAS interventions. These ChEVAS planners were blinded to the study purpose and asked to agree upon an EVAS/ChEVAS plan. The primary outcome was the percentage of the FEVAR patients in whom an EVAS/ChEVAS was technically possible. The secondary outcomes were a comparison of seal zones, number of target vessels, and device cost. RESULTS: An EVAS-based intervention would have been technically possible in 56 (93.3%) of the FEVAR patients. The median proximal aortic seal zone was significantly more distal in the EVAS/ChEVAS procedures vs the FEVAR cases (zone 8 vs zone 7, p<0.001) and fewer target vessels were involved (median 2 vs 3, p<0.001). The cost of the EVAS/ChEVAS device was 66% of the FEVAR device. Planners would not currently advocate an EVAS-based intervention in 43 (76.8%) of these 56 patients due to concerns regarding the risk of migration associated with the lumen thrombus ratios observed. CONCLUSION: EVAS is technically feasible in the majority of patients undergoing FEVAR in our institution but currently advocated in only 23.2%. The seal zone was more distal, fewer target vessels were involved, and the device cost was lower in the planned EVAS/ChEVAS interventions.

Endovascular Repair of Type IIIb Endoleak With the Amplatzer Septal Occluder.

PURPOSE: To report the successful treatment of a type IIIb endoleak with an Amplatzer Septal Occluder. CASE REPORT: A 76-year-old man was found to have a type IIIb endoleak in the proximal body component of a fenestrated graft at 4-year surveillance imaging; the leak was associated with rapid aneurysm growth. The anatomy of the graft and position of the fabric defect precluded treatment by relining with a secondary endograft. The defect was demonstrated with catheter angiography, sized with an angioplasty balloon, and repaired using an Amplatzer Septal Occluder. Follow-up imaging at 6 months showed no endoleak and marked reduction in the aneurysm size. CONCLUSION: The Amplatzer Septal Occluder may be considered as an option for managing type IIIb endoleaks.

Clinical Outcome after Endovascular Sealing of Abdominal Aortic Aneurysms: A Retrospective Cohort Study.

BACKGROUND: The aim of this study is to present the clinical outcome of endovascular aneurysm sealing (EVAS) with the Nellix endoprosthesis in patients with abdominal aortic aneurysms treated in our institution. METHODS: This is a retrospective, single center, observational cohort study. A departmental database was interrogated to extract demographics, clinical information, and outcome of all patients treated with EVAS between December 2013 and December 2015. Outcome measures included technical success (successful device deployment and absence of any endoleak at completion angiography), mortality, major complications, incidence of endoleaks, aneurysm rupture, and reintervention. RESULTS: Sixty-five patients (49 men) with a mean (standard deviation) age of 78 (6.9) years were successfully treated with EVAS, with no 30-day mortality. The cohort included 1 patient with ruptured aneurysm, 9 patients with late complications of previous aortoiliac repairs (2 open, 7 endovascular), and 4 patients who required a total of 9 visceral chimneys for juxtarenal aneurysms. Six patients (9%) suffered major postoperative complications and 4 (6%) required intervention. There were no early or late endoleaks or aneurysm ruptures. After a median (range) follow-up of 12 (0-24) months, there was no aneurysm-related mortality; 2 patients (3%) required late aneurysm-related interventions. CONCLUSIONS: EVAS can be performed with good outcomes up to 2 years postoperatively. Longer follow-up on larger cohorts is needed to prove the efficacy of this technique.

Patient selection for endovascular sac sealing of abdominal aortic aneurysm.

Endovascular sealing is a developing technique for treatment of abdominal aortic aneurysm that draws on novel concepts utilizing polymer filling of endobags within the aorto-iliac lumen. The morphologic indications and patient selection, while similar to those of endovascular aneurysm repair, differ in some regards. The Instructions for Use for the Nellix sealing device may expand the indications for aneurysm treatment and are closely scrutinized in this article. The authors draw on current evidence and their own experience and opinion in the discussion around appropriate patient selection and its influence on outcomes after endovascular aneurysm sealing. A recommendation for stricter adherence to Instructions for Use in the early phase of clinical experience is made, with acknowledgement that the natural evolution of endovascular aneurysm sealing may involve more challenging cases.

Radiologist variability in assessing the position of the cavoatrial junction on chest radiographs.

OBJECTIVE: To assess the variability in identifying the cavoatrial junction (CAJ) on chest X-rays (CXRs) amongst radiologists. METHODS: 23 radiologists (13 consultants and 10 trainees) assessed 25 posteroanterior erect CXRs (including 8 duplicates) and marked the positions of the CAJ. Differences in the CAJ position both within and between observers were evaluated and reported as limits of agreement (LOA), repeatability coefficients (RCs) and intraclass correlation coefficients and were displayed graphically with Bland-Altman plots. RESULTS: The mean difference for within-observer assessments was -0.2 cm (95% LOA, -1.5 to +1.1 cm) and between observers, it was -0.3 cm (95% LOA, -2.5 to +1.8 cm). Intraobserver RCs were marginally lower for consultants than for trainees (1.1 vs 1.5). RCs between observers were comparable (2.1 vs 2.2) for consultants and trainees, respectively. CONCLUSION: This study detected a large interobserver variability of the CAJ position (up to 4.3 cm). This is a significant finding considering that the length of the superior vena cava is reported to be approximately 7 cm. We conclude that there is poor consensus regarding the CAJ position amongst radiologists. ADVANCES IN KNOWLEDGE: No comparisons exist between radiologists in determining CAJ position from CXRs. This report provides evidence of the large observer variability amongst radiologists and adds to the discussion regarding the use of CXRs in validating catheter tip location systems.