Secondary Interventions Following Endovascular Aneurysm Repair (EVAR) and the Enduring Value of Graft Surveillance

Secondary interventions and surveillance after elective abdominal aortic aneurysm repair

BACKGROUND

The early survival benefits of endovascular aneurysm repair (EVAR) appear to diminish over time, and late aneurysm-related mortality remains a significant concern. Our aim is to determine the rate of secondary interventions (SI) and assess compliance with post-EVAR surveillance.

METHODS

This retrospective cohort study included consecutive patients who underwent elective EVAR between February 2009 and May 2019 at a tertiary center. The primary outcomes were freedom from SI and compliance with follow-up (imaging performed within a time interval of no more than 18 months). Secondary outcome was overall patient survival.

RESULTS

A total of 214 patients underwent EVAR, with a median follow-up of 44 months. During this period, 42 SI were performed in 25 patients. Of all SI, 33.3% (14/42) were due to symptomatic complications. Freedom from SI was 96.3±1.3% at 30 days and 93.6±1.7%, 90.3±2.2% and 85.9±3.0 at 1, 3 and 5 years, respectively. Endoleaks were the main cause of SI after EVAR (N.=26), primarily type 1 and type 2. At 5 years, patient survival rates were similar (76.7±4.1% vs. 84.4±7.2%, P=0.386). Compliance with surveillance was 80.4±2.9% at 1 year, and 37.7±5.4% at 5 years.

CONCLUSIONS

SI after EVAR were frequent, with endoleaks being the leading cause and associated with cases of aneurysm sac rupture. Although compliance with surveillance decreases over longer follow-up periods, the impact of this trend on long-term outcomes after EVAR warrants further investigation.

Influence of Proximal Fixation on Aneurysm Neck Evolution after Endovascular Treatment of Infrarenal Aneurysms

BACKGROUND

We analyzed the long-term influence of fixation systems on proximal aortic neck (PAN) evolution by comparing 2 late-generation endoprostheses, Endurant (Medtronic Vascular, Minneapolis, Minn) with suprarenal fixation (SRF) and Excluder (W.L Gore & Associates, Flagstaff, Ariz) with infrarenal fixation (IRF).

METHODS

Our retrospective observational study included consecutive patients undergoing endovascular aneurysm repair (EVAR) for aorto-iliac aneurysms (2011-2020). Primary end points: neck enlargement and freedom from significative PAN enlargement (5 mm). Secondary end points: neck-related reintervention, endoleaks and graft migration. Results were reported following the Society of Vascular Surgery reporting standards.

RESULTS

139 patients were included (97 in SRF group and 42 in IRF group). A difference in growth at 10 mm caudal to lowest renal artery at 2 years follow-up was found (mean growth of 1.92 ± 3.38 mm in SRF and 0.16 ± 6.86 mm in IRF; P < 0.001). A tendency to a major growth in SRF at 4 years follow-up at the lowest renal artery (1.27 ± 3.36 mm vs. 0.63 ± 2.2 mm; P = 0.06), 5 mm distal to lowest renal artery (2.17 ± 3.52 mm vs. 0.94 ± 2.76 mm; P = 0.001) and 10 mm distal to lowest renal artery (2.65 ± 3.86 mm vs. 1.12 ± 1.5 mm; P < 0.001) was shown. Freedom from PAN enlargement was 96.65% and 88.20% in SRF and 100% and 94.4% in IRF at 2 and 4 years follow-up respectively (log rank 0.041). A greater incidence of type II endoleaks in IRF was observed (40.48% vs. 15.46%; P = 0.001). Oversizing >15% showed to be a risk factor of PAN enlargement (odds ratio 6.85; 95% confident interval: 1.67-28.4; P = 0.007).

CONCLUSIONS

A small but significative percentage of patients after EVAR show a progressive PAN enlargement, being significatively greater in SRF, without increasing neck-related complications 4 years after graft deployment.

Follow-up compliance in patients undergoing abdominal aortic aneurysm repair at Veterans Affairs hospitals

OBJECTIVE

The Society for Vascular Surgery guidelines recommend annual imaging surveillance following endovascular aneurysm repair (EVAR) and every 5 years following open surgical repairs (OSR) of abdominal aortic aneurysms (AAAs). Adherence to these guidelines is low outside of clinical trials, and compliance at Veterans Affairs (VA) hospitals is not yet well-established. We examined imaging follow-up compliance and mortality rates after AAA repair at VA hospitals.

METHODS

We queried the VA Surgical Quality Improvement Program database for elective infrarenal AAA repairs, EVAR and OSR, then merged in follow-up imaging and mortality information. Mortality rate over time was derived using Kaplan-Meier estimation. Generalized estimating equation with a logit link and a sandwich standard error estimate was performed to compare the probability of having annual follow-up imaging over time between procedure types and to identify variables associated with follow-up imaging for EVAR patients.

RESULTS

Our analysis included 11,668 patients who underwent EVAR and 4507 patients who underwent OSR at VA hospitals between the years 2000 and 2019. The 30-day mortality rate for EVAR and OSR was 0.37% and 0.82%, respectively. OSR was associated with lower long-term mortality after adjusting age, sex, American Society of Anesthesiologists classification and preoperative renal failure with an adjusted hazard ratio of 0.88 (95% confidence interval, 0.84-0.92; P < .01). Of surviving patients, the follow-up imaging rate was 69.1% by 1 year post-EVAR. The follow-up rate after 5 years was 45.6% post-EVAR compared with 63.6% post-OSR of surviving patients. A history of smoking or drinking, baseline hypertension, and known cardiac disease were independently associated with poor follow-up after EVAR.

CONCLUSIONS

Patients undergoing elective open AAA repair in the VA hospital system had lower long-term mortality compared with patients who underwent endovascular repair. Compliance with post-EVAR imaging is low. Patient factors associated with poor post-EVAR imaging surveillance were smoking within the last year, excess alcohol consumption, and cardiac risk factors including hypertension, prior myocardial infarction, and congestive heart failure.

Estimation of the Added Cancer Risk Derived From EVAR and CTA Follow-Up

OBJECTIVE

The aim of this study was to assess the risk of radiation-induced cancer development in patients that have undergone an infrarenal EVAR, stratifying the relative contributions of the procedure and the preoperative and postoperative CTAs.

METHODS AND MATERIALS

The organ-specific absorbed radiation doses from CTA and the EVAR procedure were estimated from the radiation exposures of 95 and 45 male patients, respectively. Lifetime attributable risk (LAR) cancer predictions were calculated for 14 different organs. Life expectancy was assumed from a previous cohort of patients undergoing infra-renal EVAR.

RESULTS

The calculated total excess cancer risk was 0.0046, ie, 1 out of 220 patients will develop a neoplasm after being exposed to the ionizing radiation from the preoperative CTA, the EVAR and annual CTA examinations for 15 years. The procedure and the preoperative CTA contributed with 38% of the total excess risk, while the rest was derived from the follow-up. If the entire CTA based follow-up would have been eliminated, an excess risk of 0.0018 (1/560) would remain.

CONCLUSIONS

1 out of 219 patients who have undergone EVAR of an infra-renal AAA have a lifetime risk of developing cancer secondary to the radiation exposures related to the procedure and the CTAs used preoperatively and during follow-up. This risk derives mostly from the yearly postoperative CTAs, underlining the potential benefits of reducing or replacing their use.

CLINICAL IMPACT

A simulation-based estimation reinforced the potential deleterious effects of the radiation exposure for patients undergoing Endovascular Aneurysm Repair (EVAR) of Abdominal Aortic Aneurysms (AAA) and subsequently followed by yearly Computer Tomography Angiographies (CTAs). The risk could be as high as 1 out 219 patients developing a neoplasm after 15 years. The largest exposure derives from the follow-up CTAs and efforts to minimize their use as well as the intraoperative radiation are greatly needed. The simulation-based estimations done in this study reinforce potential deleterious effects of the radiation exposure for patients undergoing EVAR of AAA. Efforts should be done to minimize the intraoperative radiation and the number of CTAs used during follow-up.

Fully automatic volume segmentation using deep learning approaches to assess aneurysmal sac evolution after infra-renal endovascular aortic repair

OBJECTIVE

Endovascular aortic repair (EVAR) surveillance relies on serial measurements of maximal diameter despite significant inter- and intra-observer variability. Volumetric measurements are more sensitive but general use is hampered by the time required for their implementation. An innovative fully automated software (PRAEVAorta® from Nurea), using artificial intelligence (AI), previously demonstrated fast and robust detection of infra-renal abdominal aortic aneurysm's (AAA) characteristics on pre-operative imaging. This study aimed to assess the robustness of these data on post-EVAR computed tomography (CT) scans.

METHODS

Comparison was made between fully automatic and semi-automatic segmentation manually corrected by a senior surgeon on a dataset of 48 patients (48 early post-EVAR CT scans with 6466 slices, and a total of 101 follow-up CT scans with 13708 slices).

RESULTS

The analyses confirmed an excellent correlation of post-EVAR volumes and surfaces, as well as, proximal neck and maximum aneurysm diameters measured with the fully automatic and manually corrected segmentation methods (Pearson's coefficient correlation >.99, p<.0001). Comparison between the fully automatic and manually corrected segmentation method revealed a mean Dice Similarity Coefficient of 0.950±0.015, Jaccard index of 0.906±0.028, Sensitivity of 0.929±0.028, Specificity of 0.965±0.016, Volumetric Similarity (VS) of 0.973±0.018 and mean Hausdorff Distance/slice of 8.7±10.8mm. The mean VS reached 0.873±0.100 for the lumen and 0.903±0.091 for the thrombus. The segmentation time was 9 times faster with the fully automatic method (2.5 vs 22 min/patient with the manually corrected method; p<.0001). Preliminary analysis also demonstrated that a diameter increase of 2mm can actually represent >5% volume increase.

CONCLUSION

PRAEVAorta® enables a fast, reproducible, and fully automated analysis of post-EVAR AAA sac and neck characteristics, with comparison between different time points. It could become a crucial adjunct for EVAR follow-up through early detection of sac evolution, which may reduce the risk of secondary rupture.

Longer follow-up intervals following EVAR are safe and appropriate after marked aneurysm sac regression

BACKGROUND

Abdominal aortic aneurysm (AAA) shrinkage after endovascular aortic aneurysm repair (EVAR) is a surrogate marker for successful exclusion. Our study characterized aneurysm sac remodeling after EVAR to identify a pattern that may be associated with benign AAA behavior and would safely allow a less rigorous follow-up regimen after EVAR.

METHODS

Elective infrarenal EVARs performed between 2008 and 2011 at our institution were retrospectively reviewed. AAA sac diameters using the minor axis measurement from ultrasound imaging or computer tomography angiogram imaging were compared with the baseline diameter from the 1-month postoperative computer tomography angiogram. The primary outcome was a composite of freedom from postoperative reintervention or rupture. We compared those with AAA sacs who regressed to predefined minimum diameter thresholds with those who did not. Outcomes were plotted with Kaplan-Meier curves and compared using log-rank testing and Fine-Gray regression using death as a competing risk, clustered on graft type. For patients whose AAA reached the minimum sac diameter, landmark analysis evaluated ongoing size changes including further regression and sac re-expansion.

RESULTS

A total of 540 patients (aged 75.1 ± 8.2 years; 82.0% male) underwent EVAR with an average preoperative AAA size of 55.2 ± 11.5 mm. The median postoperative follow-up was 5.3 years (interquartile range, 1.4-8.7 years) during which 64 patients underwent reintervention and 4 ruptured. AAA sac regression to ≤40 mm in diameter was associated with improved freedom from reintervention or rupture overall (log-rank, P < .01), which was maintained after controlling for the competing risk of death (P < .01). In 376 patients (70%) whose aneurysm sac remained >40 mm, 99 reinterventions were performed on 63 patients. Of 166 (31%) patients whose sac regressed to ≤40 mm, only 1 patient required a reintervention, and no one ruptured. The mean time to a diameter of ≤40 mm was 2.3 ± 1.9 years. Only eight patients (5%) developed sac re-expansion to >45 mm; all but two occurred at least 3 years after initially regressing to ≤40 mm.

CONCLUSIONS

In long-term follow-up, patients whose minimum AAA sac diameter regressed ≤40 mm after EVAR experienced a very low rate of reintervention, rupture, or sac re-expansion. Most sac re-expansion occurred at least 3 years after reaching this threshold and did not result in clinical events. Increasing follow-up frequency up to 3-year intervals once the AAA sac regresses to 40 mm would carry minimal risk of aneurysm-related morbidity.

Intraoperative cone beam computed tomography to improve outcomes after infra-renal endovascular aortic repair

OBJECTIVE

To evaluate whether a combination of intraoperative ceCBCT and postoperative contrast enhanced ultrasound (CEUS) assessment after infra-renal endovascular aortic repair (EVAR) could reduce late stent-graft related complications and consequently re-interventions.

METHODS

All consecutive patients receiving infra-renal bifurcated stent-grafts in our hybrid room (IGS 730, GE Healthcare) during two discrete periods were included in this study: i) from November 2012 to September 2013, a 2D completion angiogram was performed after each EVAR, followed by computed tomography angiography (CTA) before discharge (group 1), ii) from October 2013 to January 2015, an intraoperative ceCBCT was performed, followed by CEUS within the first postoperative days (group 2). Comparative analyses of outcomes were undertaken. The primary endpoint was late stent-graft related complications, a composite factor incorporating aneurysm-related death, type 1 or 3 endoleaks, kink or occlusion of iliac limb and aortic sac enlargement beyond the first 30 postoperative days. The secondary endpoint was all stent-graft related re-interventions. All-cause and aneurysm related deaths were also reported.

RESULTS

Overall, 100 consecutive patients (50 in group 1 and 50 in group 2) were enrolled with a median follow up of 60 months [IQR 41-69]. At 60 months from the index procedure, freedom from late stent-graft related complications in each group was 61.6% (95 % CI [47.0-80.6]) for group 1 and 81.7% (95 % CI [70.1-95.2]) for group 2 (p=.033). Intraoperative CBCT was independently associated with a reduced rate of late stent-graft related complications after multivariate analysis (HR = 0.39, 95% CI 0.16-0.95, p=.038), but did not appear to significantly protect against stent-graft related re-interventions (HR=0.53; 95% CI 0.20-1.39, p=.198) or all cause death (p=.47).

CONCLUSION

This study is the first to report the influence of routine ceCBCT on late outcomes after EVAR and shows a potential reduction in late stent-graft related complications associated with its use.

Patient-Reported Outcomes of Yearly Imaging Surveillance in Patients Following Endovascular Aortic Aneurysm Repair

Little is known about the impact of standardized imaging surveillance on anxiety levels and well-being of patients after endovascular aortic aneurysm repair (EVAR). We hypothesize that patient anxiety levels increase just before receiving the imaging results compared with standard anxiety levels.

METHODS

Prospective cohort study from November 2018 to May 2020 including post-EVAR patients visiting the outpatient clinics of 4 Dutch hospitals for imaging follow-up. The Patient-Reported Outcomes Measurement Information System (PROMIS) was used. Patients completed the PROMIS Anxiety v1.0 Short Form (SF) 4a, PROMIS-Global Health Scale v1.2, and PROMIS-Physical Function v1.2 SF8b at 2 time points: prior to the result of the imaging study (T1: pre-visit) and 6-8 months later (T2: reference measurement). Mean T-scores at T1 were compared to T2, and T2 to the general 65+ Dutch population.

RESULTS

Altogether 342 invited patients were eligible, 214 completed the first questionnaire, 189 returned 2 completed questionnaires and 128 patients did not participate. Out of 214 respondents, 195 were male (91.1%) and the mean (standard deviation) age was 75.2 (7.0) years. There were no significant differences between T1 and T2 in anxiety levels (0.48; 95% confidence interval[CI] -0.42-1.38), global mental health (0.27; 95% CI -0.79-0.84), global physical health (0.10; 95% CI -0.38-1.18) and physical function (0.53; 95% CI -0.26-1.32). Compared with the 65+ Dutch population, at T2 patients experienced more anxiety (3.8; 95% CI 2.96-5.54), had worse global physical health (-3.2; 95% CI -4.38 - -2.02) and physical function (-2.4; 95% CI -4.00 - -0.80). Global mental health was similar (-1.0; 95% CI -2.21 - 0.21).

CONCLUSIONS

Post-EVAR patients do not experience more anxiety just before receiving surveillance imaging results than outside this period, but do suffer from more anxiety and worse physical outcomes than the 65+ Dutch population.

Comparison of the bifurcated graft reconstruction and aortic stump closure in open surgical conversion after endovascular aneurysm repair

OBJECTIVES

The optimal management of the aortic stump in open surgical conversion (OSC) after AAA endovascular aneurysm repair (EVAR) is debated. Therefore, we aimed to compare the efficacies and safety between the bifurcated prosthetic vascular graft in situ stump reconstruction (p-graft ISSR) and aortic stump closure (ASC) in OSC.

METHODS

We analyzed 973 elective AAA patients admitted from 1/1/2001 to 12/31/2020, at the First Affiliated Hospital of Sun Yat-sen University. We conducted a statistical analysis of the clinical characteristics, procedural data, as well as outcomes and technique considerations of aortic stump management in OSC patients.

RESULTS

A total of 24 male patients had OSC after EVAR. The rate of stent graft infection was 54.17% before OSC. Eleven patients underwent ASC, and 13 patients were treated with p-graft ISSR. The major complication after OSC was aortic stump bleeding (total incidence was 37.50%) (1 patient with a periaortic hematoma and 8 patients with a stump blowout). The total incidences of stump blowout between the patients with ASC and those with p-graft ISSR were significantly different (45.45% vs. 23.08%, p<0.05). The total perioperative mortality was 25.00% (6 patients with stump blowouts). The perioperative survival rates between these two aortic stump management approaches were 72.72% and 76.92% (ASC vs. p-graft ISSR, p<0.05). In total, 18 patients were followed up (3-180 months). There were 3 aorta-related deaths during the late follow-up period (including both of the 2 stump-blowout-related deaths just treated with ASC).

CONCLUSIONS

If the condition of the aorta and peri-aortic tissue are suitable for a prosthetic graft bypass, the p-graft ISSR is highly recommended for OSC patients after EVAR.

Short-Term Re-intervention of Endovascular Abdominal Aortic Aneurysm Repair

Background and aim

Endovascular aneurysm repair (EVAR) has revolutionized the management of abdominal aortic aneurysm (AAA). The re-intervention rate following EVAR has been a subject of debate in many studies. The study aims to evaluate the short-term outcomes in terms of the early (four-year) re-intervention rate following EVAR at our centre and compare it to the average re-intervention rate of the main studies assessed by the National Institute of Health and Care Excellence (NICE).

Methods

The EVAR procedures performed over two years (2015 and 2016) were retrieved using the operation codes. The clinical portal and PACS systems were used to review the discharge summaries, clinic and multidisciplinary team (MDT) letters, as well as the scans and interventional radiology procedures to assess the patients’ adherence to follow-up and identify any re-intervention procedure done to correct underlying problems related to the EVAR performed. Patients who switched their follow-up to another hospital were contacted and interviewed about any re-intervention undergone. 

Results

A total of 108 patients underwent EVAR during the two-year study period. Twenty EVAR-related re-interventions (18.5%) were recorded, irrespective of the cause or the type of intervention. This is slightly higher than the average rate by NICE (16.89%). Type 1 endoleak represented the leading cause for re-intervention (30%). Most of the cases of re-intervention were done endovascularly (60%). Forty-five percent of the patients had a re-intervention during the first year and 35% in the third year.

Conclusion

This study shows that although our re-intervention rate following EVAR was slightly higher than the international average, EVAR is still a safe method for the repair of AAA with relatively low peri-operative morbidity and mortality. However, long-term follow-up of these patients is mandatory as re-interventions are frequently required. Nonetheless, the majority of re-interventions can be done with minimal morbidity to the patient.

Simple diameter measurements with ultrasound can be safely used to follow the majority of patients after infrarenal endovascular aneurysm repair

BACKGROUND

The optimal imaging follow-up after infrarenal EVAR is still undefined. The objective was to study the outcome of a personalized follow-up program after infrarenal EVAR based on ultrasound AAA diameter measurements for low-risk patients.

METHODS

All consecutive patients followed-up locally after elective and acute infrarenal EVAR between 2010 and 2015 were retrospectively reviewed. Patients underwent CTA at 1 month post-EVAR whereby the attending surgeon defined the subsequent follow-up. Patients considered at low risk were followed with ultrasound only assessing AAA diameter at 1, 2, 3 and every 5 years postoperatively (group A). Low-risk required a favourable preoperative anatomy especially regarding the aneurysm neck, satisfactory intraoperative result and uneventful 1 month CTA (type 2 endoleaks acceptable). Patients not fulfilling the criteria for group A were followed with yearly 3-phase-CTAs (group B).

RESULTS

222 patients with a AAA median diameter of 58 (54-68) mm were included. 191 were allocated into group A and 31 in group B. Median follow-up time was 36 (24-59) months. Five year primary and primary assisted success was 82 ± 5 % and 93 ± 3 % for group A and 70 ± 13% and 93 ± 5% for group B, respectively (P= 0.042 and P= 0.504, respectively). 16 late aneurysm-related re-interventions were performed in 12 patients (7 in group A and 9 in group B). In group A, 5 re-interventions were rupture-preventing and 2 were symptomatic. All late re-interventions in group B were performed following findings on follow-up imaging. Five-year late re-intervention-free survival was 95 ± 2 % and 84 ± 7 % for groups A and B, respectively (P=0.046). Five-year survival was 80 ± 3 % and 63 ± 10 % for group A and B, respectively (P= 0.024).

CONCLUSIONS

A customized follow-up program after infrarenal EVAR based on ultrasound AAA diameter measurements in low-risk patients seems to be effective in maintaining a very high mid-term clinical success rate.

Postoperative imaging follow-up at 2 years as a predictor of long-term outcomes after endovascular aneurysm repair

OBJECTIVE

Lifelong imaging follow-up remains the reference standard after endovascular aneurysm repair (EVAR). Because the number of EVARs has been increasing, an individually optimized follow-up protocol is desirable. The aim of the present study was to investigate the possibility of creating such a protocol by evaluating patients' follow-up images and to compare the findings with their freedom from reintervention and abdominal aortic aneurysm (AAA) rupture.

METHODS

From 2000 to 2010, 282 patients with an AAA had undergone elective EVAR with the Zenith stent-graft. The patients were followed up annually until the end of 2019. The patients were categorized into two groups according to the presence of any endoleak or sac shrinkage at 2 years. Group A included those with no detectable endoleak plus aneurysm sac shrinkage of ≥5 mm (n = 137; 63%), and group B included those with any type of endoleak and/or no significant aneurysm sac shrinkage (<5 mm; n = 82; 37%).

RESULTS

The mean follow-up was 83 months (range, 0-229 months), and the overall survival at 2 years was 84% (n = 237). No significant difference was found in overall survival between groups A and B (P = .73). However, a significant difference was found in freedom from AAA rupture at 12 years, favoring group A (group A, 100%; group B, 91%; P = .002). Furthermore, in group A, the freedom from reintervention was 95% at 12 years compared with only 31% in group B (P < .001). The sensitivity of the categorization was 89% and the specificity was 74% for the finding of a complication requiring a reintervention during long-term follow-up.

CONCLUSIONS

Patients without an endoleak and a reduction of ≥5 mm in aneurysm size at 2 years had significantly fewer late reinterventions and ruptures during long-term follow-up compared with their counterparts using the Zenith stent-graft (Cook Medical, Bloomington, Ind). This finding suggests that, for these patients, the follow-up interval can be personalized and safely extended after 2 years.

Editor's Choice - A Comparison of Computed Tomography Angiography and Colour Duplex Ultrasound Surveillance Post Infrarenal Endovascular Aortic Aneurysm Repair: Financial Implications and Impact of Different International Surveillance Guidelines

OBJECTIVE

Use of colour duplex ultrasound (CDUS) and computed tomography angiography (CTA) for infrarenal endovascular aortic aneurysm repair (EVAR) surveillance differs in internationally published guidelines. This study aimed firstly to compare CDUS detection of significant sac abnormalities with CTA. Secondly, a sensitivity analysis was conducted to compare financial estimates of the, predominantly CDUS based, local and Society of Vascular Surgery (SVS) protocols, the risk stratified European Society of Vascular Surgery (ESVS) protocol, and the CTA based National Institute of Health and Care Excellence (NICE) protocol.

METHODS

Agreement between CDUS and CTA was assessed for detection of significant sac abnormalities. Surveillance protocols were extrapolated from published guidelines and applied to infrarenal EVAR patients active on local surveillance at a large, single centre. Surveillance intensity was dependent on presence of endoleak and subsequent risk of treatment failure in accordance with surveillance recommendations. Estimates for each surveillance protocol were inclusive of a range of published incidences of endoleak, contrast associated acute kidney injury (AKI), and excess hospital bed days, and estimated for a hypothetical five year surveillance period.

RESULTS

The kappa coefficient between CDUS and CTA for detecting sac abnormalities was 0.68. Maximum five year surveillance cost estimates for the 289 active EVAR patients were £272 359 for SVS, £230 708 for ESVS, £643 802 for NICE, and £266 777 for local protocols, or £1 270, £1 076, £3 003, and £1 244 per patient. Differences in endoleak incidence accounted for a 1.1 to 1.4 fold increase in costs. AKI incidence accounted for a 3.3 to 6.2 fold increase in costs.

CONCLUSION

A combined CTA and CDUS EVAR surveillance protocol, with CTA reserved for early seal assessment and confirmatory purposes, provides an economical approach without compromising detection of sac abnormalities. AKI, as opposed to direct imaging costs, accounted for the largest differences in surveillance cost estimates.

Assessment of EVAR Complications using CIRSE Complication Classification System in the UK Tertiary Referral Centre: A ∼6-Year Retrospective Analysis (2014-2019)

PURPOSE

To retrospectively analyse complications in endovascular aortic repair (EVAR) interventions and evaluate if the CIRSE (Cardiovascular and Interventional Radiological Society of Europe) complication classification system is appropriate as a standardized classification tool for EVAR patients.

MATERIALS AND METHODS

Demographic, procedural and complication data in 719 consecutive patients undergoing EVAR at one institution from January 2014 to October 2019 were retrospectively reviewed. Data (imaging reports, procedural reports, nurse notes, discharge summary reports) were collected consulting the electronic patient record system (EPR) of the hospital and cleaned and stored in a Microsoft Excel database. All the procedures were analysed in consensus by two interventional radiology consultants and a resident radiologist and if an intra- , peri- or post-procedural complication occurred, a grade (1-6) was assigned using the CIRSE grading complication classification system.

RESULTS

Twenty-five patients were excluded from the analysis because of invalid or incomplete data. The final population was made up of 694 patients (mean age 75,4 y.o., 616 male/78 female, min age 23 y.o., max age 97 y.o.). Complications emerged in 211 patients (30,4% of cases, 22 female/189 male). The number of patients with CIRSE grade I, II, III, IV, V and VI complications was 36 (17%), 17 (8%), 121 (57,3%), 15 (7,1%), 3 (1,4%), 19 (9%). Nineteen (2,6%) patients succumbed after EVAR. Thirty-four complications (16,1%) were related to vascular access.

CONCLUSION

The CIRSE complication classification system represents a broadly applicable and feasible approach to evaluate the severity of complications in patients following EVAR. However, some deficit may be considered relevant and as starting standing-point for future improvements.

Color Doppler ultrasound for surveillance following EVAR as the primary tool

OBJECTIVE

As aneurysm-related events and rupture is not eliminated, postoperative lifelong surveillance is mandatory after endovascular aneurysm repair (EVAR). For surveillance colored Doppler ultrasound (CDUS) is a standard method of noninvasive evaluation having the advantages of availability, cost-effectiveness, and lack of nephrotoxicity and radiation. We evaluated CDUS for primary surveillance tool after elective EVAR by comparing with computerized tomography.

METHODS

Between January 2018 and March 2020, 84 consecutive post-EVAR patients were evaluated. First, CDUS was performed by two Doppler operators from the Radiology Department and then computed tomographic angiography (CTA) was performed. The operators were blind to CTA reports. A reporting protocol was organized for endoleak detection and largest aneurysm diameter.

RESULTS

Among 84 patients, there were 11 detected endoleaks (13.1%) with CTA and seven of them was detected with CDUS (r = .884, p < .001). All Type I and III endoleaks were detected perfectly. There is an insufficiency in detecting low flow by CDUS. Eliminating this frailty, there was a strong correlation of aneurysm sac diameter measurement between CTA and CDUS (r = .777, p < .001). The sensitivity and specificity of CDUS was 63.6% and 100%, respectively. The accuracy was 95.2%. Positive and negative predictive values were 100% and 94.8%. Bland-Altman analysis and linear regression analysis showed no proportional bias (mean difference of 1.5 ± 2.2 mm, p = .233).

CONCLUSIONS

For surveillance, CDUS promises accurate results without missing any potential complication requiring intervention as Type I or III endoleak. Lack of detecting Type II endoleaks may be negligible as sac enlargement was the key for reintervention in this situation and CDUS has a remarkably high correlation with CTA in sac diameter measurement. CDUS may be a primary surveillance tool for EVAR and CTA will be reserved in case of aneurysm sac enlargement, detection of an endoleak, inadequate CDUS, or in case of unexplained abdominal symptomatology. By this way we not only avoid ionizing radiation and nephrotoxic agents, but also achieve cost saving issue also.

Surveillance Imaging following Endovascular Aneurysm Repair: State of the Art

Endovascular aneurysmal repair (EVAR) has become a prominent modality for the treatment of abdominal aortic aneurysm. Surveillance imaging is important for the detection of device-related complications, which include endoleak, structural abnormalities, and infection. Currently used modalities include ultrasound, X-ray, computed tomography, magnetic resonance imaging, and angiography. Understanding the advantages and drawbacks of each modality, as well available guidelines, can guide selection of the appropriate technique for individual patients. We review complications following EVAR and advances in surveillance imaging modalities.

Prediction, pattern recognition and modelling of complications post-endovascular infra renal aneurysm repair by artificial intelligence

OBJECTIVES

The study evaluates the plausibility and applicability of prediction, pattern recognition and modelling of complications post-endovascular aneurysm repair (EVAR) by artificial intelligence for more accurate surveillance in practice.

METHODS

A single-centre prospective data collection on (n = 250) EVAR cases with n = 26 preoperative attributes (factors) on endpoint of endoleak (types I-VI), occlusion, migration and mortality over a 13-year period was conducted. In addition to the traditional statistical analysis, data was subjected to machine learning algorithm through artificial neural network. The predictive accuracy (specificity and -1 sensitivity) on each endpoint is presented with percentage and receiver operative curve. The pattern recognition and model classification were conducted using discriminate analysis, decision tree, logistic regression, naive Bayes and support vector machines, and the best fit model was deployed for pattern recognition and modelling.

RESULTS

The accuracy of the training, validation and predictive ability of artificial neural network in detection of endoleak type I was 95, 96 and 94%, type II (94, 83, 90 and 82%) and type III was 96, 94 and 96%, respectively. Endpoints are associated with increase in weights through predictive modeling that were not detected through statistical analytics. The overall accuracy of the model was >86%.

CONCLUSION

The study highlights the applicability, accuracy and reliability of artificial intelligence in the detection of adverse outcomes post-EVAR for an accurate surveillance stratification.

Secondary Interventions and Long-term Follow-up after Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

Early morbidity and mortality are low after endovascular abdominal aneurysm repair (EVAR), but secondary interventions and late complications are common. The aim of the present multicenter cohort study is to detail the frequency and indication for interventions after EVAR and the impact on long-term survival.

METHODS

A retrospective multicenter cohort study of secondary interventions after elective EVAR for an infrarenal abdominal aortic aneurysm was conducted. Consecutive patients (n = 349) undergoing EVAR between January 2007 and January 2012 were analyzed, with long-term follow-up until December 2018. Those requiring intervention were classified in accordance with the indications and specific nature of the intervention and treatment. The primary study end point was overall survival classified for patients with and without intervention. Kaplan-Meier analysis was used to estimate overall survival for those who did and who did not undergo secondary interventions. Univariable and multivariable Cox regression were performed to identify independent variables associated with mortality.

RESULTS

Some 56 patients (16%) underwent 72 secondary interventions after EVAR during a median (interquartile range) follow-up period of 53.2 months (60.1). Some 45 patients (80.4%) underwent one intervention. Indications for intervention included mainly endograft kinking/outflow obstruction and type II endoleak. An endovascular technique was used in 40.3% of interventions. Median time to secondary intervention was 24.1 months. In 93 patients with abnormalities on imaging, no intervention was performed mainly because the abnormality had disappeared on follow-up imaging (43%). Kaplan-Meier curves showed no difference in survival for patients with and without secondary interventions (P = 0.153). Age (hazard ratio [HR]: 1.089, 95% confidence interval [CI]: 1.063-1.116), ASA classification (ASA III, IV HR: 1.517, 95% CI: 1.056-2.178) were significantly related to mortality.

CONCLUSIONS

Secondary intervention rates are still considerable after EVAR. Endograft kinking/outflow obstruction and endoleak type II are the most common indications for a secondary intervention. Secondary interventions did not adversely affect long-term overall survival after EVAR.

Image-Based Displacements Analysis and Computational Blood Dynamics after Endovascular Aneurysm Repair

BACKGROUND

To examine intraheartbeat displacements (IHD) and geometrical changes of endografts for abdominal aortic aneurysm repair over the course of years, defined as follow-up displacements (FUD), and to correlate them with computational fluid dynamics (CFD). Despite the widespread use of endovascular aneurysm repair (EVAR), we still know little about endograft behavior after deployment.

METHODS

Two cases, treated with either expanded polytetrafluoroethylene on a nitinol stent frame (PI) or with woven polyester fabric sutured to a stainless-steel Z stent skeleton (PII), were submitted to dynamic computed tomography angiography at 1, 12, and 60 months after implantation. After segmentation, IHD were computed as displacements of the reconstructed surface with respect to the diastolic instant. Similarly, FUD were studied using imaging techniques that align temporal successive segmentations. In addition, numerical simulations for blood dynamics were performed to compute viscous forces, specifically wall shear stress and time-averaged wall shear stress (TAWSS).

RESULTS

IHD analysis showed slight translations without deformation for the PI endograft with respect to the stiffer stainless-steel endograft behavior of PII. FUD showed in PI motion of the metallic struts mainly focused on the distal main body of the endograft and in the zone overlapping with iliac branches. In PII, we observed a huge FUD in the middle and inferior-anterior regions of the main body. CFD analysis revealed changes of velocity patterns associated with remodeling of the iliac zone for PI and of the main body region for PII, where flow impinges the lumen wall and progressively induces deformation of the endograft wires. Measurement of TAWSS demonstrated flow disturbances in the enlarged region correlated with displacement analysis.

CONCLUSIONS

Image-based displacement analysis associated with CFD enabled very subtle evaluations of endograft behavior on different temporal scales. This kind of study could be helpful both for physicians, forecasting evolution during the life span of the endograft, and manufacturers, giving them useful information about endograft implant performance and design.

Geometrical changes in Anaconda endograft limbs after endovascular aneurysm repair: A potential predictor for limb occlusion

The emergence of limb occlusion after endovascular aneurysm repair may be related to the conformational changes between the endograft structure and the patient's anatomy. This study analyzed detailed geometric changes of Anaconda endograft (Terumo Aortic, Inchinnan, Scotland, UK) limbs during the cardiac cycle-based computed tomography on serial imaging after graft implantation. Fifteen patients (mean age 72.8 ± 3.7 years; 14 men) underwent postoperative electrocardiogram-gated computed tomography scans according to a prospective study design between April 2014 and May 2017. Changes in curvature, length of the limbs, and distances between successive stent rings (inter-ring distance) of the endograft limbs during a 2-year follow-up period were quantified using meticulous image processing methods involving image registration, centerline extraction, and model-based stent-ring segmentation. From discharge to 24 months, mean curvature increased significantly by 9.6 m^-1 (standard deviation [SD], 11.1 m^-1; 95% confidence interval [CI], 3.4 to 15.8 m^-1; P = .002) for the right limbs and by 6.1 m^-1 (SD 9.4 m^-1; 95% CI, 0.8 to 11.5 m^-1; P = .21) for the left limbs. The length of the right limbs decreased significantly, by 9.5 mm (SD 7.6 mm; 95% CI, 3.5 to 15.6 mm; P = .002); the length of the left limbs decreased by 10.1 mm (SD 5.1 mm; 95% CI, 5.9 to 14.2 mm; P < .001). The minimal inter-ring distance decreased by 0.36 mm (SD 0.26 mm; 95% CI, 0.17 to 0.55 mm; P < .001) for the right limbs and 0.35 mm (SD 0.19 mm; 95% CI, 0.21 to 0.49 mm; P < .001) for the left limbs. Cardiac pulsatility-induced changes in curvature, limb length, and inter-ring distance were negligible (2%, 0.3% and 0.3%, respectively). Changes in the geometry of the Anaconda endograft limbs after endovascular aortic aneurysm repair were observed during a 2-year follow-up manifest as an increase in curvature, shortening of the stent-graft limbs, and a corresponding decrease in inter-ring distance. These stent-graft conformational changes could result in inward folding of the graft fabric, which may relate to the emergence of limb occlusion. Further investigation of these metrics in a larger cohort involving patients with and without occlusions may allow determination of their predictive value.

Analysis of Midterm Outcomes of Endovascular Aneurysm Repair in Octogenarians From the ENGAGE Registry

PURPOSE

To assess periprocedural results and secondary endovascular procedure outcomes over 5 years in patients aged ≥80 vs <80 years undergoing endovascular aneurysm repair (EVAR).

MATERIALS AND METHODS

Data from the Endurant Stent Graft Natural Selection Global post-market registry (ENGAGE) were used for the analyses. A total of 1263 consecutive patients were enrolled in the prospective, observational, single-arm registry and divided into 2 groups according to age: ≥80 years (290, 22.9%) and <80 years (973, 77.1%). Baseline patient characteristics, risk scores according to the Society for Vascular Surgery (SVS) reporting standards, American Society of Anesthesiologists (ASA) classification, quality of life assessments [EuroQol 5 (EQ5D) index], and treatment outcomes, including all-cause mortality, aneurysm-related mortality, major adverse events, secondary endovascular procedures, and endoleaks were compared between groups.

RESULTS

Octogenarians were classified into the highest category of the SVS risk stratification system; however, this did not result in a significant difference in the 30-day mortality [1.4% (4/290) vs 1.2% (12/973) for controls; p=0.85] or major adverse event rates [5.2% (15/290) vs 3.6% (35/973), p=0.23]. Multivariable analysis confirmed that age ≥80 years, pulmonary disease, large aneurysm diameter, and renal insufficiency were significantly associated with all-cause mortality, whereas diameter was the only parameter associated with increased aneurysm-related mortality. The differences in freedom from secondary endovascular procedures over 5 years between octogenarians and controls did not reach statistical significance (88.5% vs 83.2%, p=0.07).

CONCLUSION

EVAR can be performed in individuals aged ≥80 years with no statistically significant difference in midterm aneurysm-related deaths compared with younger patients. The findings in this elderly patient cohort show that EVAR can be safely performed with acceptable morbidity rates in octogenarians.

Endovascular treatment of para-anastomotic aneurysms after open abdominal aortic surgery

INTRODUCTION

The repair of long-term complications of open abdominal aortic repair such as para-anastomotic aneurysm (PAA) and pseudoaneurysm (PSA) is very challenging. The aim of this study was to assess the outcomes of endovascular repair of PAA/PSA after previous open aortic surgery for aneurismal or occlusive disease.

EVIDENCE ACQUISITION

A systematic review was undertaken; a search was performed (PRISMA) in MEDLINE, CENTRAL, Cochrane databases and key references of all studies of endovascular treatment of PAA/PSA after open aortic surgery.

EVIDENCE SYNTHESIS

Eighteen studies included totally 433 patients (86.3% males) with mean age of 71±2.5 years were identified. Most of the patients were asymptomatic (76%) and diagnosed with PAA (60.5%), while 81.6% had history of open aortic reconstruction for aneurismal disease. The mean diameter of para-anastomotic aneurysms was 59.7 mm (from 23 mm to 110 mm) and the mean duration until their diagnosis was 10±2 years. Standard bifurcated (23.7%), fenestrated (23.4%) and aorto-uni-iliac stent-grafts (16.3%) were mostly used. The technical success rate was 97.8% (391/400) with 1.4% (6/433) 30 day-mortality rate and mean hospital stay of 6±3 days. The mean 1- and 2- year survival rate was 87.8% and 78.8%, respectively. The follow-up ranged from 9 to 43 months, with presenting complications such as endoleak type I (24/378; 6.3%), type II (15/354; 4.3%), type III (3/378;0.8%), migration (4/378; 1%) and limb occlusion (5/310;1.6%). Additionally, 5.7% (19/332) of the patients underwent open conversion, while the total re-intervention rate was 11.4% (39/340; time of reintervention ranged from 7 to 30 months). In cases in which a stent was used for splanchnic vessels (renal artery: 188, superior mesenteric artery: 98, celiac artery: 64), the primary patency rate was 97.4% (341/350).

CONCLUSIONS

Endovascular treatment of PAAs and PSAs after previous open aortic surgery is a feasible and efficient option with high technical success rate, low 30-day mortality and good mid-term outcomes.

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.

Total Luminal Volume Predicts Risk after Endovascular Aneurysm Repair

OBJECTIVE

Large aneurysm diameter represents a well known predictor of late complications after endovascular aneurysm repair (EVAR). However, the role of the thrombus free lumen inside the abdominal aortic aneurysm (AAA) sac is not clear. It was hypothesised that greater luminal volume represents a relevant risk factor for late complications after EVAR.

METHODS

A retrospective cohort analysis was performed including all patients undergoing EVAR from 2005 to 2016 at a tertiary referral institution. Pre-operative AAA lumen volume was measured in centre lumen line reconstructions and patients were stratified into quartiles according to luminal volume. The primary endpoint was freedom from AAA related complications. Secondary endpoints were freedom from neck events (type 1A endoleak, migration >5 mm or any pre-emptive neck related intervention), iliac related events (type 1B endoleak or pre-emptive iliac related intervention), and overall survival.

RESULTS

Four hundred and four patients were included: 101 in the first quartile (Q1; <61 cm³). Patients with higher luminal volumes had wider, shorter, and more angulated proximal necks. There were more ruptured AAAs, more aorto-uni-iliac implanted devices and patients outside neck instructions for use in the 4th quartile. Five year freedom from AAA related complications was 79%, 66%, 58% and 56%, respectively (p = .007). At five years, freedom from neck related events was 86%, 84%, 73%, and 71%, respectively, for the four groups (p = .009), and freedom from iliac related events was 96%, 91%, 88%, and 88%, respectively (p = .335). On multivariable analysis, luminal volume was an independent predictor of late complications (Q4 vs. Q1 - hazard ratio: 1.91, 95% confidence interval 1.01-3.6, p = .046). Overall survival at five years was not affected by lumen volume (p = .75).

CONCLUSION

AAA luminal volume represents an important risk factor for AAA related complications. This information may be considered when deciding tailoring surveillance protocols after EVAR. However, larger studies are needed to validate this hypothesis.

Suprarenal Aortic Remodeling after Endovascular Aortic Aneurysm Repair among Three Endografts with Different Types of Proximal Fixation System

BACKGROUND

Remodeling of suprarenal aorta after endovascular aortic aneurysm repair (EVAR) in relation to different endograft designs has not been thoroughly investigated. The aim of this study is to assess the anatomical configuration of the suprarenal aorta after using endografts with different proximal fixation during the first post-EVAR year.

METHODS

A retrospective study including EVAR patients using 3 types of endografts with different proximal fixation systems according to Instructions for Use was undertaken (50: Ovation, Endologix, Irvin, CA; 25: Endurant IIs, Medtronic, Santa Rosa, CA; 25: Excluder C3, W. L. Gore & Associates, Flagstaff, AZ). Comorbidities were recorded. Anatomic variables of the supra-aortic anatomy, abdominal aortic aneurysm (AAA) maximum diameter, and neck angulation were analyzed. Computed tomography angiography was obtained preoperatively at 1 and 12 months post-EVAR, while a duplex scan was undertaken at 6 months.

RESULTS

Comorbidities were not different across the 3 groups. Presence and amount of neck calcification (P = 0.139) and thrombus (P = 0.116) was similar among groups. Maximum aortic diameter showed significant reduction from preoperative measurements to 12-month postoperative ones, for all groups. (Ovation: 56.5 to 53 mm, P < 0.001; Endurant: 57 to 51 mm, P < 0.001; Excluder: 55 to 50 mm, P < 0.001). Suprarenal angulation was decreased significantly in the Ovation (P < 0.001) and Excluder groups (P = 0.05), while the infrarenal angulation was decreased in all groups. Among endografts, the decrease in AAA maximum diameter was similar (P = 0.99), while the suprarenal aortic diameter was significantly increased in Ovation patients in comparison to the other 2 endografts at the level of 5 mm (P = 0.02) and 25 mm (P = 0.01). Suprarenal angulation reduction was similar (P = 0.7), while infrarenal angulation was significantly more decreased in Ovation endograft than the other 2 systems (P < 0.001).

CONCLUSIONS

Proximal endograft configuration appears to have different impact on supra-aortic anatomy. Longer follow-up is needed to clarify future remodeling and clinical impact of these observations.

Combined transbrachial and transfemoral strategy to deploy an iliac branch endoprosthesis in the setting of a pre-existing endovascular aortic aneurysm repair

This article describes brachial access to position a long sheath in the abdominal aorta in conjunction with a large caliber sheath via the femoral artery ipsilateral to the target site to deliver a 0.018 bodyfloss wire. This bodyfloss wire is inserted into the precannulation port of the iliac branch endoprosthesis (W. L. Gore and Associates, Flagstaff, Ariz), which is then advanced from the groin. Once the bifurcated device is deployed, hypogastric access and stenting is achieved from the upper extremity. This technique is an alternative to safely extend the distal seal while preserving the hypogastric artery and has the advantage of limited iliac bifurcation manipulation.

Tight systolic blood pressure control with combination therapy decreases type 2 endoleaks in patients undergoing endovascular aneurysm repair

BACKGROUND

Endovascular aneurysm repair (EVAR) has revolutionized the treatment of abdominal aortic aneurysm (AAA) disease. However, the survival advantage is lost in the long term due the occurrence of endoleaks affecting the late rupture of aneurism sac. Few data are available on the role of blood pressure control in affecting the incidence of type 2 endoleaks in patients undergoing EVAR.

OBJECTIVE

Aim of this study was to evaluated whether systolic blood pressure (SBP) control to target 130 mmHg reached after preoperative cardiology consultant might decrease the incidence of type II endoleak(T2E), sac expansion and related aortic reintervention after elective endovascular aneurysm repair(EVAR).

METHODS

We analyzed 386 patients undergoing EVAR between 2008 and 2016. The primary endpoints were T2E, sac expansion and related aortic re-intervention or sac shrinkage during a median follow-up of 24 months [12-48]. The secondary endpoint was every cause of vascular or cardiac morbidity and mortality.

RESULTS

The SBP value of 130 mmHg at the time of EVAR resulted, at ROC curve analysis, the most sensitive and specific for all the analyzed endpoints (T2E, n = 74; sac expansion n = 19; re-intervention, n = 10, sac shrinkage, n = 72). The combination antihypertensive therapy showed a significant inverse relationship with T2E occurrence. The incidence of primary endpoints was significantly higher (p < 0.001) in patients with SBP ≥ 130 mmHg. Cardiovascular death was significantly more prevalent (p < 0,001) in patients with SBP ≥130 mmHg. These findings were confirmed at the multivariable Cox regression analysis [primary endpoint HR = 0.09(0.06-0.15), p < 0.001; cardiovascular death HR = 0.33(0.12-0.85), p = 0.023].

CONCLUSIONS

Tight SBP control at the target of 130 mmHg at the time of elective EVAR significantly decreases TE2 occurrence, need of re-intervention and cardiovascular death in a prolonged follow-up of a large sample of patients.

Complication Incidences and Treatment Outcomes of Endovascular Aneurysm Repair-A Single-Center Long-Time Follow-Up Study

BACKGROUND

Few long-time follow-up studies describe all complications, treatment outcome of complications, and mortality in relation to endovascular aneurysm repair (EVAR). The purpose of this study was to evaluate the incidence and treatment outcome including mortality of radiological visible complications related to the EVAR procedure at a single center with up to 10 years' surveillance.

MATERIALS AND METHODS

Patients treated with EVAR from March 2006 to March 2016 at a Danish university hospital, 421 in total, were included. Patient and aneurysm characteristics, follow-up, and secondary intervention data were collected from a national database and medical records. Follow-up computed tomography angiography and plain abdominal X-ray reports were reviewed for complications. Scans and X-rays with suspected complications were evaluated by an interventional radiologist.

RESULTS

A total of 172 complications in 147 patients, mainly in the beginning of the follow-up period, were found; 35% had a least one complication. The main part of complications (62%) was type II endoleaks, followed by stent graft stenosis (11%), type I endoleaks (9%), and stent graft occlusion (7%). A total of 66 (38%) complications, observed in 55 patients, were treated with reintervention, of which 77% were treated with endovascular procedures and 23% with surgical treatment, that is, 13% of all studied patients had a complication that required a reintervention. The remaining 2 of the 3 complications were treated conservatively. We found no increased all-cause mortality in connection with having a complication including those requiring reintervention.

CONCLUSION

We presented a 10-year single-center study of EVAR. Many patients treated with EVAR had a radiological visible complication, mainly in the beginning of the follow-up period. Only a smaller fraction required reintervention and having a reintervention-requiring complication was not connected to increased mortality.

Positron Emission Tomography/Computed Tomography Predicts and Detects Complications After Endovascular Repair of Abdominal Aortic Aneurysms

Purpose: To assess if aortic 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography/computed tomography (PET/CT) could play a role in predicting complications after endovascular aneurysm repair (EVAR). Materials and Methods: This study involved 2 cohorts of men with abdominal aortic aneurysm treated by EVAR: those who underwent a PET/CT scan before EVAR (n=17) and those who had a PET/CT during follow-up (n=34). Uptake of FDG was measured as the standardized uptake value (SUV). D-dimer, a marker of fibrinolysis, was measured in blood drawn concomitantly with the PET/CT. Results: A significant uptake of FDG in the aneurysm wall was detected by PET/CT before EVAR in 6 of 17 patients. During the first year after EVAR, type II endoleaks developed in 5 of these FDG+ patients vs 3 of 11 FDG- patients (p=0.04). Two of the FDG+ patients had continued sac growth and required conversion to open repair. A significant association between sac growth rate, SUV, and the presence of endoleak was found in the 34 patients who underwent PET/CT after EVAR. Finally, D-dimer was significantly increased in patients with both endoleak and positive PET/CT in the post-EVAR group. Conclusion: This study suggests that the presence of FDG uptake in the aortic wall might be a useful tool to predict patients at high risk of developing post-EVAR complications.

Contrast-enhanced ultrasound and/or colour duplex ultrasound for surveillance after endovascular abdominal aortic aneurysm repair: a systematic review and economic evaluation

BACKGROUND

Endovascular abdominal aortic aneurysm repair (EVAR) of abdominal aortic aneurysm (AAA) is less invasive than open surgery, but may be associated with important complications. Patients receiving EVAR require long-term surveillance to detect abnormalities and direct treatments. Computed tomography angiography (CTA) has been the most common imaging modality adopted for EVAR surveillance, but it is associated with repeated radiation exposure and the risk of contrast-related nephropathy. Colour duplex ultrasound (CDU) and, more recently, contrast-enhanced ultrasound (CEU) have been suggested as possible, safer, alternatives to CTA.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of imaging strategies, using either CDU or CEU alone or in conjunction with plain radiography, compared with CTA for EVAR surveillance.

DATA SOURCES

Major electronic databases were searched, including MEDLINE, EMBASE, Science Citation Index, Scopus' Articles-in-Press, Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE) and NHS Economic Evaluation Database from 1996 onwards. We also searched for relevant ongoing studies and conference proceedings. The final searches were undertaken in September 2016.

METHODS

We conducted a systematic review of randomised controlled trials and cohort studies of patients with AAAs who were receiving surveillance using CTA, CDU and CEU with or without plain radiography. Three reviewers were involved in the study selection, data extraction and risk-of-bias assessment. We developed a Markov model based on five surveillance strategies: (1) annual CTA; (2) annual CDU; (3) annual CEU; (4) CDU together with CTA at 1 year, followed by CDU on an annual basis; and (5) CEU together with CTA at 1 year, followed by CEU on an annual basis. All of these strategies also considered plain radiography on an annual basis.

RESULTS

We identified two non-randomised comparative studies and 25 cohort studies of interventions, and nine systematic reviews of diagnostic accuracy. Overall, the proportion of patients who required reintervention ranged from 1.1% (mean follow-up of 24 months) to 23.8% (mean follow-up of 32 months). Reintervention was mainly required for patients with thrombosis and types I-III endoleaks. All-cause mortality ranged from 2.7% (mean follow-up of 24 months) to 42% (mean follow-up of 54.8 months). Aneurysm-related mortality occurred in < 1% of the participants. Strategies based on early and mid-term CTA and/or CDU and long-term CDU surveillance were broadly comparable with those based on a combination of CTA and CDU throughout the follow-up period in terms of clinical complications, reinterventions and mortality. The economic evaluation showed that a CDU-based strategy generated lower expected costs and higher quality-adjusted life-year (QALYs) than a CTA-based strategy and has a 63% probability of being cost-effective at a £30,000 willingness-to-pay-per-QALY threshold. A CEU-based strategy generated more QALYs, but at higher costs, and became cost-effective only for high-risk patient groups.

LIMITATIONS

Most studies were rated as being at a high or moderate risk of bias. No studies compared CDU with CEU. Substantial clinical heterogeneity precluded a formal synthesis of results. The economic model was hindered by a lack of suitable data.

CONCLUSIONS

Current surveillance practice is very heterogeneous. CDU may be a safe and cost-effective alternative to CTA, with CTA being reserved for abnormal/inconclusive CDU cases.

FUTURE WORK

Research is needed to validate the safety of modified, more-targeted surveillance protocols based on the use of CDU and CEU. The role of radiography for surveillance after EVAR requires clarification.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016036475.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Importance of Follow-up Imaging in the Detection of Delayed Type 2 Endoleaks Despite Complete Aneurysmal Sac Shrinkage

Type 2 endoleaks usually constitute a benign and self-limited phenomenon, which rarely leads to aneurysmal sac expansion. However, in a small subset of patients, a persistent type 2 endoleak might pressurise the aneurysmal sac causing expansion. The authors present two cases with delayed new-onset type 2 endoleak. One occurred after standard endovascular aortic repair and the other after chimney endovascular aortic repair, causing expansion of the aneurysmal sac after a period of complete aneurysmal sac shrinkage. Accordingly, there is a risk of sac re-expansion due to delayed onset endoleaks, independent of the technique, justifying the need for a continuous follow-up despite long-term aneurysmal sac shrinkage.

Usefulness of Abdominal Duplex Ultrasound for Detecting Endoleaks after Endovascular Aneurysm Repair

Objective: The usefulness of abdominal duplex ultrasound (DUS) for the detection of endoleaks after endovascular aneurysm repair (EVAR) was evaluated. Materials and Methods: Among 286 patients who underwent EVAR between September 2007 and July 2017, 241 patients were followed up using abdominal DUS. Endoleaks were detected in 74 patients (31%), who were divided into enlarged and nonenlarged sac groups. Endoleak velocities and widths were measured using abdominal DUS every 6 months after EVAR and were compared between the 2 groups. Results: The aneurysm diameter in the nonenlarged sac group was 54.4±8.7 mm in the final follow-up. None of the patients in the nonenlarged sac group were subjected to reintervention, whereas all patients in the enlarged sac group were subjected to reintervention. The aneurysm diameter in the enlarged sac group was 62.8±8.8 mm at the time of reintervention, and the maximum endoleak flow velocities and endoleak widths were significantly higher in the enlarged sac group than in the nonenlarged sac group (p<0.05). The cutoff values on receiver operating characteristics curves for endoleak velocity and width were 83.4 cm/s and 4.0 mm, respectively. Conclusion: Follow-ups using abdominal DUS are useful after EVAR. Endoleak velocity and width measurements are important, and reintervention may be needed when these measurements exceed their cutoff values.

Contemporary imaging methods for the follow-up after endovascular abdominal aneurysm repair: a review

Abdominal aortic aneurysm (AAA) is defined as a localized enlargement of the aortic cross-section where the diameter is greater than 3 cm or more than 50% larger than the diameter in a normal segment. The most important complication of AAA is rupture, which, if untreated, results in mortality rates of up to 90%. Conventional open surgical repair is associated with significant 30-day mortality. Endovascular aneurysm repair (EVAR) is a significantly less invasive procedure; it is related to a lower early mortality rate and a lower number of perioperative complications. Although EVAR is a minimally invasive technique, lifelong follow-up imaging is necessary due to possible late complications including endoleak, recurrent aneurysm formation, graft infection, migration, kinking and thrombosis. The total rate of complications after EVAR is estimated at approximately 30%, and the rate of complications that require intervention is 2–3%. Early detection and progression analysis of such situations is crucial for proper intervention.

Comparison of major adverse event rates after elective endovascular aneurysm repair in New England using a novel measure of complication severity

OBJECTIVE

Major adverse event (MAE) rates are used as an outcome measure after surgical procedures. Although MAE rates summarize the occurrences of adverse events, they do not reflect differences in severity of these events. We propose that a measure of complication severity could provide a more accurate assessment about the quality of care. We aimed to analyze and to describe the regional variation in elective endovascular aneurysm repair (EVAR) MAE rates across centers in the Vascular Study Group of New England and to create an index for describing complication severity.

METHODS

Patients undergoing elective EVAR (n = 4731) at 30 Vascular Study Group of New England centers between 2003 and 2016 were studied. The MAE composite end point was defined as the occurrence of any of the following postoperative events: myocardial infarction, dysrhythmia, congestive heart failure, leg ischemia, renal insufficiency, bowel complication, reoperation, surgical site infection, stroke, respiratory complication, and no home discharge. An adjustment factor (complication severity index) was calculated as a ratio of length of stay for complicated to uncomplicated cases. Multivariate logistic regression was used to calculate predicted MAE rates. The observed and predicted MAE rates as well as complication severity index rates were compared among centers and across quintiles of center volume.

RESULTS

Observed MAE rates varied widely, ranging from 0% to 39%. Multivariate predictors of MAE included abdominal aortic aneurysm diameter >6 cm (odds ratio [OR], 2.1; 95% confidence interval [CI], 2.0-2.3), female sex (OR, 2.0; 95% CI, 1.8-2.2), chronic renal insufficiency (OR, 1.9; 95% CI, 1.7-2.1), age >75 years (OR, 1.9; 95% CI, 1.8-2.1), congestive heart failure (OR, 1.7; 95% CI, 1.5-1.9), chronic obstructive pulmonary disease (OR, 1.5; 95% CI, 1.4-1.6), diabetes (OR, 1.4; 95% CI, 1.1-1.7), positive stress test result (OR, 1.2; 95% CI, 1.1-1.4), preoperative beta blocker (OR, 1.2; 95% CI, 1.1-1.3), and no preoperative statin (OR, 1.2; 95% CI, 1.1-1.3). Predicted MAE rates had little variation (range, 21%-29%). In comparing observed MAE rates and complication severity, there was an inverse relation between the two, suggesting that although certain centers had a greater number of MAEs, the complications were less severe.

CONCLUSIONS

MAE rates after elective EVAR vary widely. However, centers with higher MAE rates tended to have less severe complications, suggesting that observed MAE rates may not be a good measure of outcomes assessment after elective EVARs.

Complications of endovascular aneurysm repair of the thoracic and abdominal aorta: evaluation and management

In recent decades, endovascular aneurysm repair or endovascular aortic repair (EVAR) has become an acceptable alternative to open surgery for the treatment of thoracic and abdominal aortic aneurysms and other aortic pathologies such as the acute aortic syndromes (e.g., penetrating aortic ulcer, intramural hematoma, dissection). Available data suggest that endovascular repair is associated with lower perioperative 30-day all-cause mortality as well as a significant reduction in perioperative morbidity when compared to open surgery. Additionally, EVAR leads to decreased blood loss, eliminates the need for cross-clamping the aorta and has shorter recovery periods than traditional surgery. It is currently the preferred mode of treatment of thoracic and abdominal aortic aneurysms in a subset of patients who meet certain anatomic criteria conducive to endovascular repair. The main disadvantage of EVAR procedures is the high rate of post-procedural complications that often require secondary re-intervention. As a result, most authorities recommend lifelong imaging surveillance following repair. Available surveillance modalities include conventional radiography, computed tomography, magnetic resonance angiography, ultrasonography, nuclear imaging and conventional angiography, with computed tomography currently considered to be the gold standard for surveillance by most experts. Following endovascular abdominal aortic aneurysm (AAA) repair, the rate of complications is estimated to range between 16% and 30%. The complication rate is higher following thoracic EVAR (TEVAR) and is estimated to be as high as 38%. Common complications include both those related to the endograft device and systemic complications. Device-related complications include endoleaks, endograft migration or collapse, kinking and/or stenosis of an endograft limb and graft infection. Post-procedural systemic complications include end-organ ischemia, cerebrovascular and cardiovascular events and post-implantation syndrome. Secondary re-interventions are required in approximately 19% to 24% of cases following endovascular abdominal and thoracic aortic aneurysm repair respectively. Typically, most secondary reinterventions involve the use of percutaneous techniques such as placement of cuff extension devices, additional endograft components or stents, enhancement of endograft fixation, treatment of certain endoleaks using various embolization techniques and embolic agents and thrombolysis of occluded endograft components. Less commonly, surgical conversion and/or open surgical modification are required. In this article, we provide an overview of the most common complications that may occur following endovascular repair of thoracic and AAAs. We also summarize the current surveillance recommendations for detecting and evaluating these complications and discuss various current secondary re-intervention approaches that may typically be employed for treatment.

Two-Year Outcomes of the Nellix EndoVascular Aneurysm Sealing System for Treatment of Abdominal Aortic Aneurysms

Purpose: To analyze the 2-year outcomes of endovascular aneurysm sealing (EVAS) according to 2 versions of the instructions for use (IFU). Methods: A retrospective study was conducted involving 355 consecutive patients treated with the first-generation EVAS device from April 2013 to December 31, 2015, at 3 high-volume centers. Out of 355 patients treated with EVAS, 264 were elective asymptomatic infrarenal EVAS procedures suitable for analysis. In this cohort, 168 (63.3%) patients were treated within the IFU 2013 criteria; of these 48 (18.2%) were in compliance with the revised IFU 2016 version. Results: Overall technical success was 98.2% (165/168) in the IFU 2013 group and 97.9% (47/48) in the IFU 2016 subgroup (p=0.428). The 2-year freedom from reintervention estimates were 89.7% (IFU 2013) and 95.7% (IFU 2016), with significantly more reinterventions in the first 45 cases (p=0.005). The stenosis/occlusion estimates were 6.5% (IFU 2013) and 4.2% (IFU 2016; p=0.705). Nine (5.4%) endoleaks (8 type Ia and 1 type Ib) were observed within the IFU 2013 cohort; 3 (2.1%) were in the IFU 2016 subgroup (p=0.583). Migration ≥10 mm or ≥5 mm requiring intervention was reported in 12 (7.1%) patients in the IFU 2013 cohort but none within the IFU 2016 subgroup. Ten (6.0%) patients demonstrated aneurysm growth in the IFU 2013 cohort, of which 2 (4.2%) were in the IFU 2016 subgroup. Overall survival and freedom from aneurysm-related death estimates at 2 years were 90.9% and 97.6% in the IFU 2013 cohort (IFU 2016: 95.5% and 100.0%). The prevalence of complications seemed lower within IFU 2016 without significant differences. Conclusion: This study shows acceptable 2-year results of EVAS used within the IFU, without significant differences between the 2 IFU versions, though longer follow-up is indicated. The refined IFU significantly reduced the applicability of the technique.

An Alternative Approach for Treating a Type Ia Endoleak after Conventional EVAR Using the Nellix Endovascular Aneurysm Sealing

BACKGROUND

To report the use of a Nellix endovascular aneurysm sealing (EVAS) device, to successfully treat a type Ia endoleak (EL) after an endovascular aortic repair (EVAR).

CASE REPORT

A 70-year-old man was diagnosed with a 90-mm aortic aneurysm, suspicious for being inflammatory. It was initially treated successfully, with a Medtronic Endurant (Medtronic, Minneapolis, MN, USA). Five years after the index endovascular repair, an asymptomatic type Ia EL was detected on duplex ultrasound and computed tomographic angiogram. Other endovascular solutions in the form of proximal cuff, chimney was considered difficult to execute due to challenges in planning, manipulation, and renal cannulation caused by the short proximal sealing zone above the existing stent graft and the constraints of the previous endograft. Thus, a relining of the previous endoprothesis was performed using the Nellix system (Endologix, Inc., Irvine, CA, USA). One-year follow-up imaging demonstrated successful resolution of the EL and persistent sealing of the Nellix device.

CONCLUSIONS

Nellix EVAS system can be an alternative and safe option for relining a stent graft with a type Ia EL. Nellix platform can be added to the clinician's armamentarium for treating type Ia EL after conventional EVAR of infrarenal abdominal aortic aneurysm (AAA).

Editor's Choice - The Implications of Non-compliance to Endovascular Aneurysm Repair Surveillance: A Systematic Review and Meta-analysis

OBJECTIVE/BACKGROUND

Increasingly, reports show that compliance rates with endovascular aneurysm repair (EVAR) surveillance are often suboptimal. The aim of this study was to determine the safety implications of non-compliance with surveillance.

METHODS

The study was carried out according to the Preferred Items for Reporting of Systematic Reviews and Meta-Analyses (PRISMA) guidelines. An electronic search was undertaken by two independent authors using Embase, MEDLINE, Cochrane, and Web of Science databases from 1990 to July 2017. Only studies that analysed infrarenal EVAR and had a definition of non-compliance described as weeks or months without imaging surveillance were analysed. Meta-analysis was carried out using the random-effects model and restricted maximum likelihood estimation.

RESULTS

Thirteen articles (40,730 patients) were eligible for systematic review; of these, seven studies (14,311 patients) were appropriate for comparative meta-analyses of mortality rates. Three studies (8316 patients) were eligible for the comparative meta-analyses of re-intervention rates after EVAR and four studies (12,995 patients) eligible for meta-analysis for abdominal aortic aneurysm related mortality (ARM). The estimated average non-compliance rate was 42.0% (95% confidence interval [CI] 28-56%). Although there is some evidence that non-compliant patients have better survival rates, there was no statistically significant difference in all cause mortality rates (year 1: odds ratio [OR] 5.77, 95% CI 0.74-45.14; year 3: OR 2.28, 95% CI 0.92-5.66; year 5: OR 1.81, 95% CI 0.88-3.74) and ARM (OR 1.47, 95% CI 0.99-2.19) between compliant and non-compliant patients in the first 5 years after EVAR. The re-intervention rate was statistically significantly higher in compliant patients from 3 to 5 years after EVAR (year 1: OR 6.36, 95% CI 0.23-172.73; year 3: OR 3.94, 85% CI 1.46-10.69; year 5: OR 5.34, 95% CI 1.87-15.29).

CONCLUSION

This systematic review and meta-analysis suggests that patients compliant with EVAR surveillance programmes may have an increased re-intervention rate but do not appear to have better survival rates than non-compliant patients.

Late Sac Rupture due to a Type IV Endoleak after Previous Endovascular Aortic Aneurysm Repair: A Case Report

Type IV endoleaks have been identified as endoleaks of low flow, and rupture risk has been estimated to be minimal in literature. Therefore, conservative treatment has been recommended in most cases. We are presenting a rare case of late rupture due to type IV endoleak that was treated with open repair applying a novel surgical technique.