Systematic Review and Meta-Analysis of the Effect of Anticoagulation on Outcomes After Endovascular Aneurysm Repair.

PURPOSE: Our objective was to investigate whether patients who receive anticoagulation therapy have different outcomes after endovascular aneurysm repair (EVAR) from those who do not. MATERIALS AND METHODS: We conducted a systematic review of studies that compared outcomes of EVAR in patients who were on therapeutic anticoagulation vs those who were not. We developed and reported the review in accordance with the PRISMA guidelines with a registered protocol (CRD42022375894). The Ovid interface was used to search Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica Database (EMBASE), and Cochrane Central Register of Controlled Trials (CENTRAL) up to November 2022. The quality of studies was assessed with the Newcastle-Ottawa Scale (NOS) (maximum score=9), and the evidence was appraised with the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework. The hazard ratio (HR) and 95% confidence interval (CI) was the effect estimate in time-to-event meta-analyses, calculated using the inverse-variance statistical method and random-effects models. RESULTS: Sixteen studies qualified for inclusion reporting a total of 35 739 individuals. Anticoagulated patients had a statistically significantly higher hazard of death (HR=1.93, 95% CI=1.03-3.63), endoleak (HR=2.13, 95% CI=1.55-2.93), reintervention (HR=1.79, 95% CI=1.27-2.52), and aneurysm sac expansion (HR=2.72, 95% CI=1.57-4.72) than patients not receiving anticoagulation therapy. The median score on the NOS was 7 (range=4-9). The certainty of evidence was very low for mortality and reintervention and low for endoleak and sac expansion. CONCLUSIONS: Anticoagulation is a poor prognostic factor after standard EVAR and should be considered in decision-making, consent processes, and surveillance strategies. CLINICAL IMPACT: The number of individuals who take anticoagulation treatment has been rapidly increasing over the recent years. We aimed to investigate the effect of such treatment on outcomes after endovascular aneurysm repair (EVAR). Anticoagulated patients were found to have increased mortality, endoleak, and reintervention rates after EVAR compared to their non-anticoagulated counterparts. Anticoagulation therapy has a prognostic role in EVAR and should be considered in decision making and EVAR surveillance. Anticoagulated patients need to be informed of the higher failure rates of EVAR, and intensified surveillance strategies may need to be implemented in this patient cohort.

Systematic Review With Meta-Analysis of Endovascular Versus Open Repair of Abdominal Aortic Aneurysm Repair in the Young.

PURPOSE: The purpose of this study was to investigate which treatment method for abdominal aortic aneurysm (AAA), endovascular or open repair, has better outcomes in young patients. MATERIALS AND METHODS: A systematic review was conducted to identify observational studies or randomized controlled trials (RCTs) that compared endovascular and open repair of intact AAA in young patients. MEDLINE, EMBASE, and CENTRAL were searched up to March 2022 using the Ovid interface. The risk of bias was assessed with the Newcastle-Ottawa scale (NOS), with a maximum score of 9, or version 2 of the Cochrane risk of bias tool. The certainty of evidence was assessed with the GRADE framework. Primary outcomes were perioperative, overall, and aneurysm-related mortality. Secondary outcomes were reintervention, hospital length of stay, and perioperative complications. Effect measures in syntheses were the odds ratio (OR), risk difference (RD), mean difference (MD), or hazard ratio (HR) and were calculated with the Mantel-Haenszel or inverse variance statistical method and random-effects models. RESULTS: Fifteen observational studies and 1 RCT were included, reporting a total of 48 976 young patients. Definitions of young ranged from 60 to 70 years. The median score on the NOS was 8 (range: 4-9), and the RCT was judged to be high risk of bias. The perioperative mortality was lower after EVAR (RD: -0.01, 95% CI: -0.02 to -0.00), but the overall and aneurysm-related mortality was not significantly different between EVAR and open repair (HR: 1.38, 95% CI: 0.81 to 2.33; HR: 4.68, 95% CI: 0.71 to 31.04, respectively), as was the hazard of reintervention (HR: 1.50, 95% CI: 0.88 to 2.56). The hospital length of stay was shorter after EVAR (MD: -4.44 days, 95% CI: -4.79 to -4.09), and the odds of cardiac (OR: 0.22, 95% CI: 0.13 to 0.35), respiratory (OR: 0.17, 95% CI: 0.11 to 0.26), and bleeding complications were lower after EVAR (OR: 0.26, 95% CI: 0.11 to 0.64). The level of evidence was low or very low. CONCLUSION: Patient preferences and perspectives should be considered during shared decision-making process considering the available evidence. EVAR may be considered in young and fit patients with a suitable anatomy. PROTOCOL REGISTRATION: PROSPERO, CRD42022325051. CLINICAL IMPACT: Uncertainty surrounds the optimal treatment strategy for abdominal aortic aneurysm in young patients. Meta-analysis of some 48,976 young patients showed that endovascular aneurysm repair (EVAR) has a lower perioperative mortality and morbidity and a shorter hospital and intensive care unit stay than open surgical repair, but the overall and aneurysm-related mortality in the short to medium term are not significantly different between EVAR and open repair. EVAR can be considered in young patients.

Editor's Choice - Meta-Analysis of Compliance with Endovascular Aneurysm Repair Surveillance: The EVAR Surveillance Paradox.

OBJECTIVE: To compare the survival of patients who attended surveillance after endovascular aneurysm repair (EVAR) with those who were non-compliant. DATA SOURCES: MEDLINE and Embase were searched using the Ovid interface. REVIEW METHODS: A systematic review was conducted complying with the PRISMA guidelines. Eligible studies compared survival in EVAR surveillance compliant patients with non-compliant patients. Non-compliance was defined as failure to attend at least one post-EVAR follow up. The risk of bias was assessed with the Newcastle-Ottawa scale, and the certainty of evidence using the GRADE framework. Primary outcomes were survival and aneurysm related death. Effect measures were the hazard ratio (HR) or odds ratio (OR) and 95% confidence interval (CI) calculated using the inverse variance or Mantel-Haenszel statistical method and random effects models. RESULTS: Thirteen cohort studies with a total of 22 762 patients were included. Eight studies were deemed high risk of bias. The pooled proportion of patients who were non-compliant with EVAR surveillance was 43% (95% CI 36 - 51). No statistically significant difference was found in the hazard of all cause mortality (HR 1.04, 95% CI 0.61 - 1.77), aneurysm related mortality (HR 1.80, 95% CI 0.85-3.80), or secondary intervention (HR 0.66, 95% CI 0.31 - 1.41) between patients who had incomplete and complete follow up after EVAR. The odds of aneurysm rupture were lower in non-compliant patients (OR 0.63, 95% CI 0.39 - 1.01). The certainty of evidence was very low for all outcomes. Subgroup analysis for patients who had no surveillance vs. those with complete surveillance showed no significant difference in all cause mortality (HR 1.10, 95% CI 0.43 - 2.80). CONCLUSION: Patients who were non-compliant with EVAR surveillance had similar survival to those who were compliant. These findings question the value of intense surveillance in all patients post-EVAR and highlight the need for further research on individualised or risk adjusted surveillance.

Endovascular Versus Surgical Treatment for All Comer Patients With Prosthetic Bypass Graft Occlusion: The Multicentre ENSUPRO Study.

OBJECTIVE: Bypass surgery plays a key role in complex lower limb lesions. However, there is a lack of evidence regarding the management of symptomatic prosthetic bypass graft (PBG) occlusion. This study aimed to report outcomes following open, hybrid, or endovascular management of patients presenting with symptomatic PBG occlusion. METHODS: A multicentre, retrospective cohort study was conducted, including patients presenting with PBG occlusion between January 2014 and December 2021 from 18 centres. It assessed the comparative value of treatment strategies, including (1) recanalisation of native vessels, (2) endovascular treatment of the failed PBG, (3) hybrid treatment, and (4) open surgery. The primary outcome measure was amputation free survival (AFS, time to major amputation and or death), whereas all cause mortality, major amputation, PBG re-occlusion, target lesion revascularisation (TLR), and Rutherford category (RC) improvement during follow up were considered as secondary endpoints. RESULTS: Of 260 patients with occluded PBGs, 108 (41.5%) were treated endovascularly (24 [22.2%] by recanalisation of native vessels and 84 [77.7%] by PBG re-opening), 57 (21.9%) underwent hybrid revascularisation, and 58 (22.3%) had surgery. In addition, 27 (10.4%) were treated conservatively and 10 (3.8%) received systemic thrombolysis. With a median follow up of 1.4 (0.6 - 3.0) years, AFS was 95.5%, 76.4%, 45.5%, and 37.1%, respectively in Groups 1 - 4 (p = .007). Older age and non-endovascular treatment (HR 1.05 and 1.70; p < .01 for both) were independent predictors of poor AFS. Endovascular treatment was associated with lower rates of major amputation (p = .04), PBG re-occlusion (p < .001), and TLR (p = .037), and higher RC improvements (p < .001), whereas all cause mortality was comparable between treatment groups (p = .21). CONCLUSION: Endovascular treatment is associated with higher rates of AFS and RC improvement and lower rates of PBG re-occlusion and TLR in patients with PBG occlusion.

Systematic Review of the Effect of Cerebrospinal Fluid Drainage on Outcomes After Endovascular Descending Thoracic/Thoraco-Abdominal Aortic Aneurysm Repair.

OBJECTIVE: This study aimed to investigate whether prophylactic use of cerebrospinal fluid (CSF) drainage in endovascular descending thoracic aortic aneurysm (DTAA) and thoraco-abdominal aortic aneurysm (TAAA) repair contributes to a lower rate of post-operative spinal cord ischaemia (SCI). DATA SOURCES: MEDLINE, Embase, and CINAHL. REVIEW METHODS: A literature review was conducted in accordance with PRISMA guidelines (PROSPERO registration no. CRD42021245893). Risk of bias was assessed through the Newcastle-Ottawa scale (NOS), and the certainty of evidence was graded using the GRADE approach. A proportion meta-analysis was conducted to calculate the pooled rate and 95% confidence interval (CI) of both early and late onset SCI. Pooled outcome estimates were calculated using the odds ratio (OR) and associated 95% CI. The primary outcome was SCI, both early and lateonset. Secondary outcomes were complications of CSF drainage, length of hospital stay, and peri-operative (30 day or in hospital) mortality rates. RESULTS: Twenty-eight observational, retrospective studies were included, reporting 4 814 patients (2 599 patients with and 2 215 without CSF drainage). The NOS showed a moderate risk of bias. The incidence of SCI was similar in patients with CSF drainage (0.05, 95% CI 0.03 ‒ 0.08) and without CSF drainage (0.05, 95% CI 0.00 ‒ 0.14). No significant decrease in SCI was found when using CSF drainage (OR 0.67, 95% CI 0.29 ‒ 1.55, p = .35). The incidence rate of CSF drainage related complication was 0.10 (95% CI 0.04 ‒ 0.19). The 30 day and in hospital mortality rate with CSF drainage was 0.08 (95% CI 0.05 ‒ 0.12). The 30 day and in hospital mortality rate without CSF drainage and comparison with late mortality and length of hospital stay could not be determined due to lack of data. The quality of evidence was considered very low. CONCLUSION: Pre-operative CSF drainage placement was not related to a favourable outcome regarding SCI rate in endovascular TAAA and DTAA repair. Due to the low quality of evidence, no clear recommendation on pre-operative use of CSF drainage placement can be made.

Effect of Sac Asymmetry, Neck and Iliac Angle on the Hemodynamic Behavior of Idealized Abdominal Aortic Aneurysm Geometries.

BACKGROUND: Abdominal aortic aneurysms (AAAs) are currently treated based on the universal maximum diameter criterion, but other geometric variables may play a role in the risk of rupture. The hemodynamic environment inside the AAA sac has been shown to interact with several biologic processes which can affect prognosis. AAA geometric configuration has a significant impact in the hemodynamic conditions that develop, which has only been recently realized, with implications for rupture risk estimations. We aim to perform a parametric study to evaluate the effect of aortic neck angulation, angle between the iliac arteries, and sac asymmetry (SA) on the hemodynamic variables of AAAs. METHODS: This study uses idealized AAA models and it is parametrized in terms of 3 quantities as follows: the neck angle, φ (°), iliac angle, θ (°), and SA (%), each of which accepts 3 different values, specifically φ = (0°, 30°, 60°), θ = (40°, 60°, 80°), and SA = (S, °SS, °OS), where the SA can either be on the same side with respect to neck (SS) or on the opposite side (OS). Time average wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and the velocity profile are calculated for different geometric configurations, while the percentage of the total surface area under thrombogenic conditions, using thresholds previously reported in the literature, is also recorded. RESULTS: In case of an angulated neck and a higher angle between iliac arteries, favorable hemodynamic conditions are predicted with higher TAWSS and lower OSI and RRT values. The area under thrombogenic conditions reduces by 16-46% as the neck angle increases from 0° to 60°, depending on the hemodynamic variable under consideration. The effect of iliac angulation is present but less pronounced with 2.5-7.5% change between the lower and the higher angle. The effect of SA seems to be significant for OSI, with a nonsymmetrical configuration being hemodynamically favorable, which in the presence of an angulated neck is more pronounced for the OS outline. CONCLUSIONS: Favorable hemodynamic conditions develop inside the sac of idealized AAAs with increasing neck and iliac angles. Regarding the SA parameter, asymmetrical configurations most often appear advantageous. Concerning the velocity profile the triplet (φ, θ, SA) may affect outcomes under certain conditions and thus should be taken into account when parametrizing the geometric characteristics of AAAs.

Pre-Emptive Embolization of the Aneurysm Sac or Aortic Side Branches in Endovascular Aneurysm Repair: Meta-Analysis and Trial Sequential Analysis of Randomized Controlled Trials.

BACKGROUND: To investigate outcomes of pre-emptive embolization of the aneurysm sac or aortic side branches in endovascular aneurysm repair (EVAR). METHODS: The review was reported as per Preferred Reporting Items for Systematic reviews and Meta-Analyses 2020 with a preregistered protocol. Bibliographic sources (MEDLINE, Embase, and CENTRAL) were searched using subject headings and free text terms. Randomized controlled trials comparing EVAR with versus without embolization were included. Pooled estimates of dichotomous outcomes were calculated using odds ratio (OR) or risk difference (RD) and 95% confidence interval (CI) applying the Mantel-Haenszel method. Continuous outcomes were summarized using mean difference (MD) and 95% CI applying the inverse variance method. The certainty of evidence was appraised with the Grading of Recommendations Assessment, Development, and Evaluation framework. Version 2 of the Cochrane tool was used to assess the risk of bias. Trial sequential analysis assumed alpha = 5% and power = 80%. RESULTS: Four randomized controlled trials were included. No significant difference was found in aneurysm-related mortality (RD 0.00, 95% CI -0.03 to 0.03), overall mortality (OR 1.85, 95% CI 0.42-8.13), aneurysm rupture (RD 0.00, 95% CI -0.03 to 0.03), type II endoleak-related reintervention (RD -0.07, 95% CI -0.21 to 0.06), procedure time (MD 20.12, 95% CI -11.54 to 51.77), or fluoroscopy time (MD 11.17, 95% CI -11.22 to 33.56). Patients with pre-emptive embolization had significantly lower odds of type II endoleak (OR 0.45, 95% CI 0.26-0.78) and sac expansion (OR 0.19, 95% CI 0.07-0.52). The risk of bias was high for all outcomes. The certainty of evidence was very low for all outcomes, except for type II endoleak, for which it was low. Trial sequential analysis showed an inconclusive result for overall mortality and type II endoleak-related reintervention but confirmed the advantage of embolization in reducing type II endoleak and sac expansion. CONCLUSIONS: Limited, low certainty data suggest pre-emptive embolization confers no clinical benefits in EVAR.

Late Neck Related Adverse Events are Rare Among Patients with Wide Aortic Neck Undergoing Endovascular Aneurysm Repair with the Ovation Endograft.

BACKGROUND: Patients with wide aortic necks undergoing Endovascular Aneurysm Repair (EVAR) have been shown to be at a higher risk for neck-related complications. We aim to examine outcomes of EVAR with an endograft exerting minimal outward pressure (Ovation-Endologix) in patients with a large baseline neck diameter. METHODS: We performed a retrospective single center study, including consecutive patients undergoing EVAR with the Ovation system from May 2011 to April 2021. Patients were divided in Groups 1 and 2 if the 20, 23, 26, 29 mm or the 34 mm proximal diameter main body was used, respectively. According to the instructions for use of the device, for neck diameters 27-30 mm the 34 mm main body is required. Primary endpoint was rate of neck related complications during follow-up, (type Ia endoleak, migration >10 mm and neck-related re-interventions) and rate of aortic neck dilatation (AND). AND was determined based on multiple aortic neck diameters that were recorded and compared between the 1-month computed tomography angiography (CTA) after EVAR and the last available follow-up CTA.Secondary endpoints were peri-procedural and follow-up outcomes such as endoleaks, reinterventions and overall mortality. RESULTS: In total 281 patients were included, 222 in Group 1 and 59 in Group 2. Patients in Group 2 presented significantly shorter neck length, higher neck angulation and more common reversed tapered configuration. Median follow-up was 36 months (Range: 6-106). Early and late type Ia endoleak was observed in 4 and 2 patients in each group, respectively (P = 0.063 and P = 0.195, respectively). Distal migration was observed in 2 patients in Group 2 and AND was recorded in 2 patients in each group (P = 0.195). Freedom from the primary endpoint was estimated at 98%, 94%, 94% at 12-, 36-, 60-months for Group 1 and at 98%, 95%, 86% for Group 2 (P-Value 0.266). Probability of survival was 95%, 86%, 75% at 12-, 36-, 60-months for Group 1 and 83%, 77%, 72% for Group 2 (P-Value 0.226).Multivariate regression analysis identified neither Group 1 versus Group 2 nor absolute value of aortic neck diameter as significant predictors of neck-related adverse events. Neck diameters did not display significant differences over time in any of the levels evaluated. CONCLUSIONS: EVAR with the Ovation endograft results in low rates of late neck related complications which is also true for patients with wide baseline aortic necks.

Prediction of abdominal aortic aneurysm growth by artificial intelligence taking into account clinical, biologic, morphologic, and biomechanical variables.

OBJECTIVES: To develop a prediction model that could risk stratify abdominal aortic aneurysms (AAAs) into high and low growth rate groups, using machine learning algorithms based on variables from different pathophysiological fields. METHODS: A cohort of 40 patients with small AAAs (maximum diameter 32-53 mm) who had at least an initial and a follow-up CT scan (median follow-up 12 months, range 3-36 months) were included. 29 input variables from clinical, biological, morphometric, and biomechanical pathophysiological aspects extracted for predictive modeling. Collected data were used to build two supervised machine learning models. A gradient boosting (XGboost) and a support vector machines (SVM) algorithm were trained with 60% and tested with 40% of the data to predict which AAA would achieve a growth rate higher than the median of our study cohort. Receiver operating characteristics (ROC) curves and areas under the curve (AUC) were used for the evaluation of the developed algorithms. RESULTS: XGboost achieved the highest AUC in predicting high compared to low AAA growth rate with an AUC of 81.2% (95% CI from 61.1 to 100%). SVM achieved the second highest performance with an AUC of 68.8% (95% CI from 46.5 to 91%). Based on the best performing algorithm, variable importance was estimated. Diameter-diameter ratio (maximum diameter/neck diameter), Tortuosity from Renal arteries to aortic bifurcation, and maximum thickness of the intraluminal thrombus were found to be the most important factors for model predictions. Other factors were also found to play a significant but less important role. CONCLUSIONS: A prediction model that can risk stratify AAAs into high and low growth rate groups could be developed by analyzing several factors implicated in the multifactorial pathophysiology of this disease, with the use of machine learning algorithms. Future studies including larger patient cohorts and implementing additional risk markers may aid in the establishment of such methodology during AAA rupture risk estimation.

Dual-Energy Computed Tomography as an Adjunct in the Evaluation of Peripheral Chronic Total Occlusions: A Feasibility Study.

This study investigated the role of dual-energy computed tomography (CT) for lesion characterization in patients with peripheral arterial disease manifesting with chronic total occlusions (CTOs). Forty-one symptomatic patients with CTOs underwent dual-energy CT angiography before endovascular treatment. The lesions were subsequently analyzed in a dedicated workstation, and 2 indexes-dual-energy index (DEI) and effective Z (Zeff)-were calculated, ranging from 0.0027 to 0.321 and from 6.89 to 13.02, respectively. Statistical analysis showed a significant correlation between the DEI and Zeff values (P < .001). The interobserver intraclass correlation coefficient was 0.91 for the mean Zeff values and 0.86 for the mean DEI values. This technique could potentially provide useful information regarding the composition of a CTO.

Editor's Choice - Endovascular Aneurysm Repair in High Risk Patients: A Systematic Review and Meta-Analysis.

OBJECTIVE: To investigate outcomes of endovascular aneurysm repair (EVAR) in high risk patients. METHODS: Bibliographic sources (MEDLINE, EMBASE, CINAHL, and CENTRAL) were searched using combinations of thesaurus and free text terms. The review protocol was registered in PROSPERO (CRD42021287207) and reported according to PRISMA 2020. Pooled estimates were calculated using odds ratio (OR) or hazard ratio (HR) and 95% confidence interval (CI) applying the Mantel-Haenszel or inverse variance method. EVAR peri-operative mortality in high risk patients over time was examined with mixed effects meta-regression. The GRADE framework was used to rate the certainty of evidence. RESULTS: The pooled peri-operative mortality in 18 416 high risk patients who underwent EVAR was 3% (95% CI 2.3 - 4%) and has significantly reduced over time (year of publication p = .003; median study point p = .023). The peri-operative mortality was significantly lower in high risk patients treated with EVAR compared with open repair (OR 0.64; 95% CI 0.45 - 0.92), but no significant difference was found in overall (HR 1.06; 95% CI 0.76 - 1.49) or aneurysm related mortality (HR 0.57; 95% CI 0.21 - 1.55). No significant difference was found in overall mortality between high risk patients treated with EVAR vs. no intervention (HR 0.42; 95% CI 0.14 - 1.26), but the aneurysm related mortality was significantly lower in the former (HR 0.30; 95% CI 0.14 - 0.63). The peri-operative mortality was higher in high risk than normal risk patients treated with EVAR (OR 2.33; 95% CI 1.75 - 3.10), as was the overall mortality (HR 3.50; 95% CI 2.55 - 4.80). The certainty of evidence was very low for EVAR vs. open surgery or no intervention and low for high vs. normal risk patients. CONCLUSION: The EVAR peri-operative mortality in high risk patients has improved over time. Even though the aneurysm related mortality of EVAR is lower compared with no intervention, EVAR may confer no overall survival benefit.

Multiple Sites of Arterial Thrombosis in A 35-Year Old Patient after ChAdOx1 (AstraZeneca) Vaccination, Requiring Emergent Femoral and Carotid Surgical Thrombectomy.

BACKGROUND: Vaccine Induced Thrombotic Thrombocytopenia (VITT) is a rare complication following ChAdOx1 (AstraZeneca) vaccination. Venous thrombosis in unusual sites such as splachnic or intracranial thrombosis, is the commonest manifestation. CASE REPORT: We report a 35-year-old male patient who presented with acute left leg ischemia and thrombocytopenia 11-days after vaccination requiring emergent thrombectomy. During work-up, a localized thrombus was detected in the left carotid bifurcation mandating carotid thrombectomy. Localized right iliac thrombus causing a non-limiting flow stenosis was treated conservatively. The platelet aggregating capacity of patient's plasma was confirmed in a functional assay, thereby establishing VITT. CONCLUSION: To the best of our knowledge this is the first case presenting multiple arterial thromboses requiring surgical treatment after ChAdOx1 vaccination.

Meta-Analysis of the Crossed Versus Standard Limb Configuration in Endovascular Aneurysm Repair.

OBJECTIVE: To investigate whether the crossed-limb technique confers better or worse clinical outcomes compared to the standard straight limb configuration in standard endovascular aneurysm repair (EVAR). METHODS: We conducted a systematic review to identify studies comparing outcomes of EVAR with the crossed versus standard limb configuration. MEDLINE, EMBASE, CINAHL, and CENTRAL were searched in March 2021 using the Healthcare Databases Advanced Search interface developed by the National Institute for Heath and Care Excellence. The risk of bias was assessed with the Newcastle-Ottawa scale (NOS) and the Risk Of Bias In Non-randomized Studies - of Interventions (ROBINS-I) tool. Summary estimates were calculated using the odds ratio (OR), risk difference (RD), or mean difference (MD) and 95% confidence interval (CI), applying the Mantel-Haenszel or inverse variance statistical method. Random-effects models were employed. RESULTS: Four observational studies qualified for inclusion, reporting a total of 1132 patients. All presented contemporary experiences. Baseline clinical characteristics were largely similar between patients with and without the crossed-limb configuration, but the anatomy tended to be less favourable in patients treated with the crossed-limb technique. No statistically significant difference was found in the primary outcomes: limb occlusion (OR 1.44, 95% CI 0.65 - 3.19), type Ib endoleak (RD 0.01, 95% CI -0.03 - 0.04), type III endoleak (RD 0.01, 95% CI -0.01 - 0.03); or secondary outcomes: perioperative mortality (RD 0.00, 95% CI -0.03 - 0.03), type Ia endoleak (RD 0.00, 95% CI -0.03 - 0.02), type II endoleak (OR 1.38, 95% CI 0.51 - 3.74), procedure duration (MD 18.07 min, 95% CI -1.14-37.29). Inconsistency across studies was low for all outcomes. The studies were judged to be of high quality on the NOS. The main bias identified using the ROBINS-I tool was due to confounding. CONCLUSIONS: The crossed-limb technique was not found to confer inferior clinical outcomes in the medium term compared to the standard limb configuration in patients who undergo standard EVAR.

Should the Proximal Part of a Bifurcated Aortic Graft be Kept as Short as Possible? A Computational Study Elucidates on Aortic Graft Hemodynamics for Various Main Body Lengths.

BACKGROUND: It is accepted that surgically placed bifurcated aortic grafts should be shaped as a short proximal main tube with two long distal limbs. We aim to investigate the hemodynamic effect of different main body lengths in bifurcated aortic grafts using 3D computer models. METHODS: Five different idealized models are generated to represent an aorto-bifemoral graft. Distance from renal to femoral arteries is set at 25cm and distance between the femoral arteries is set at 14cm. Values of the main body length taken into account to build the idealized models are 3cm, 6cm, 9cm, 12cm and 15cm. Blood flow resistance, Time Average Wall Shear Stress (TAWSS), Oscillatory Shear Index (OSI) and Relative Residence Time (RRT) are estimated using the constructed 3D models. RESULTS: The total resistance decreased monotonically by as far as 40% as the main body length increased. Appropriate hemodynamic simulations show a maximum TAWSS decrease and a corresponding maximum OSI and RRT increase with elongated main body configurations, indicating a hemodynamic benefit of the "Short" main body configuration. Nevertheless, the differences in these later variables are small, affecting a limited portion of the geometries. CONCLUSION: A long main body of a bifurcated aortic graft results in significantly reduced total resistance in idealized models designed to represent an aorto-bifemoral surgical graft, while the differences observed in TAWSS, OSI and RRT between models are small.

Radiomics and machine learning to predict aggressive type 2 endoleaks after endovascular aneurysm repair: a proof of concept.

BACKGROUND: Persistent type 2 endoleaks (T2EL) require lifelong surveillance to avoid potentially life-threatening complications. PURPOSE: To evaluate the performance of radiomic features (RF) derived from computed tomography angiography (CTA), for differentiating aggressive from benign T2ELs after endovascular aneurysm repair (EVAR). MATERIAL AND METHODS: A prospective study was performed on patients who underwent EVAR from January 2018 to January 2020. Analysis was performed in patients who were diagnosed with T2EL based on the CTA of the first postoperative month and were followed at six months and one year. Patients were divided into two groups according to the change of aneurysm sac dimensions. Segmentation of T2ELs was performed and RF were extracted. Feature selection for subsequent machine-learning analysis was evaluated by means of artificial intelligence. Two support vector machines (SVM) classifiers were developed to predict the aneurysm sac dimension changes at one year, utilizing RF from T2EL at one- and six-month CTA scans, respectively. RESULTS: Among the 944 initial RF of T2EL, 58 and 51 robust RF from the one- and six-month CTA scans, respectively, were used for the machine-learning model development. The SVM classifier trained on one-month signatures was able to predict sac expansion at one year with an area under curve (AUC) of 89.3%, presenting 78.6% specificity and 100% sensitivity. Similarly, the SVM classifier developed with six-month radiomics data showed an AUC of 95.5%, specificity of 90.9%, and sensitivity of 100%. CONCLUSION: Machine-learning algorithms utilizing CTA-derived RF may predict aggressive T2ELs leading to aneurysm sac expansion after EVAR.

Time-to-event data meta-analysis of late outcomes of endovascular versus open repair for ruptured abdominal aortic aneurysms.

OBJECTIVE: We investigated whether the well-documented perioperative survival advantage of emergency endovascular aneurysm repair (EVAR) compared with open repair would be sustained during follow-up. METHODS: A systematic review conforming to the PRISMA (preferred reporting items for systematic reviews and meta-analyses) statement standards was conducted to identify studies that had reported the follow-up outcomes of endovascular vs open repair for ruptured abdominal aortic aneurysms. Electronic bibliographic sources (MEDLINE [medical literature analysis and retrieval system online], Embase [Excerpta Medica database], CINAHL [cumulative index to nursing and allied health literature], and CENTRAL [Cochrane central register of controlled trials]) were interrogated using the Healthcare Databases Advanced Search interface (National Institute for Health and Care Excellence, London, United Kingdom). A time-to-event data meta-analysis was performed using the inverse variance method, and the results were reported as summary hazard ratios (HRs) and associated 95% confidence intervals (CIs). Mixed effects regression was applied to investigate the outcome changes over time. The quality of the body of evidence was appraised using the GRADE (grades of recommendation, assessment, development, and evaluation) system. RESULTS: Three randomized controlled trials and 22 observational studies reporting a total of 31,383 patients were included in the quantitative synthesis. The mean follow-up duration across the studies ranged from 232 days to 4.9 years. The overall all-cause mortality was significantly lower after EVAR than after open repair (HR, 0.79; 95% CI, 0.73-0.86). However, the postdischarge all-cause mortality was not significantly different (HR, 1.10; 95% CI, 0.85-1.43). The aneurysm-related mortality, which was reported by one randomized controlled trial, was not significantly different between EVAR and open repair (HR, 0.89; 95% CI, 0.69-1.15). Meta-regression showed the mortality difference in favor of EVAR was more pronounced in more recent studies (P = .069) and recently treated patients (P = .062). The certainty for the body of evidence for overall and postdischarge all-cause mortality was judged to be low and that for aneurysm-related mortality to be high. CONCLUSIONS: EVAR showed a sustained mortality benefit during follow-up compared with open repair. A wider adoption of an endovascular-first strategy is justified.

A systematic review and meta-analysis of the streamliner multilayer flow modulator stent for treatment of complex aortic lesions.

OBJECTIVE: We evaluated the safety and efficacy of multilayer flow modulator (MFM) stents (Cardiatis, Isnes, Belgium) for the treatment of complex aortic lesions. METHODS: A systematic electronic research was conducted for studies reported from December 2008 to May 2020. Data extracted from 15 eligible case series (CS) were appropriately pooled and analyzed in a meta-analysis. The patient baseline characteristics were recorded, and 16 outcomes of interest were studied. The primary end points included 30-day all-cause and aneurysm-related mortality, aneurysm-related mortality at 1 year, vessel patency, and any endoleaks, ruptures, reinterventions, and aneurysm exclusion at the end of follow-up. RESULTS: A total of 39 studies (15 CS and 24 case reports), involving 429 patients, met the inclusion criteria. Overall, 436 lesions were treated, and 1521 aortic branches were covered by the multilayer stent. The mean follow-up for the 15 CS with 404 patients was 14.6 months. Compliance with the instructions for use was reported by eight CS, with 75% of the procedures performed within the instructions for use. However, 41% of the patients reported by 12 CS had undergone a previous aortic intervention. The pooled 30-day all-cause and 30-day aneurysm-related mortality rates were 0.56% (95% confidence interval [CI], 0.00%-2.54%) and 0.00% (95% CI, 0.00%-0.80%), respectively. The pooled aneurysm-related mortality at 1 year of follow-up was 5.25% (95% CI, 0.07%-14.91%). The pooled vessel patency at the end of follow-up was 99.12% (95% CI, 97.73%-99.93%). The pooled reintervention and endoleak rates at the end of follow-up were 10.94% (95% CI, 3.64%-20.67%) and 10.70% (95% CI, 4.45%-18.66%), respectively. The crude spinal cord ischemia and renal failure rates were 0.69% and 1.8%, respectively. CONCLUSIONS: The results from the present review and meta-analysis have indicated the safety and efficacy of MFM stents for treating challenging aortic pathologic lesions when used as first-line treatment and within the instructions for use. The almost zero pooled 30-day all-cause and aneurysm-related mortality rates combined with the low crude spinal cord ischemia and renal failure rates indicate the use of MFM stents is a good treatment option for complex aortic lesions in the short- and mid-term periods. The lack of long-term follow-up warrants further research concerning the efficacy of the device in the long term.

Early Left Ventricular Global Longitudinal Strain Deterioration After Aortic Aneurysm Repair: Impact of Aortic Stiffness.

PURPOSE: To associate the impact of aortic reconstruction using currently available grafts and endografts on pulse wave velocity in patients with abdominal aortic aneurysm (AAA) and to evaluate its effect on early cardiac systolic function indices. MATERIALS AND METHODS: Seventy-three consecutive patients with AAA (mean age 70±8 years; all men) who underwent open (n=12) or endovascular repair (EVAR; n=61) were prospectively enrolled in an observational cohort study. Left ventricular global longitudinal strain (GLS; an important diagnostic and prognostic index of early systolic dysfunction) and carotid-femoral pulse wave velocity (cf-PWV) were estimated 1 week preoperatively, as well as at 1 and 6 months postoperatively. RESULTS: A significant time effect was found for cf-PWV, which showed an increase at 1 month that remained through 6 months (p=0.007). Additionally, a deterioration in GLS values was revealed, with a significant change at 1 month that persisted 6 months later (p<0.001). No significant group effect was observed between EVAR and open repair (p=0.98), and there was no significant interaction (p=0.96). Notably, the difference in GLS between baseline and 6 months significantly correlated with the corresponding changes in cf-PWV (r=0.494, p<0.001). CONCLUSION: AAA repair leads not only to an increase in aortic stiffness, as measured by the increase in pulse wave velocity, but also to reduced cardiac systolic function. Our findings highlight the need for a more intense cardiac surveillance program after aortic reconstruction. Further studies are needed to investigate how this may translate into long-term manifestations of cardiovascular complications and symptomatology.

Discrimination of High-Risk Type-2 Endoleak after Endovascular Aneurysm Repair through CT Perfusion: A Feasibility Study.

A type-2 endoleak after an endovascular aneurysm repair is the most prevalent type of endoleak, but as the clinical consequence of its diagnosis is uncertain, at present, management decisions are solely based on aneurysm sac growth. The aim of this study was to investigate the potential of various computed tomography perfusion parameters for their ability to distinguish high-risk type-2 endoleaks from low-risk type-2 endoleaks after an endovascular aneurysm repair.

Editor's Choice - Systematic Review and Meta-Analysis of the Impact of Institutional and Surgeon Procedure Volume on Outcomes After Ruptured Abdominal Aortic Aneurysm Repair.

OBJECTIVE: To investigate whether there is a correlation between institutional or surgeon case volume and outcomes in patients with ruptured abdominal aortic aneurysm (rAAA). DATA SOURCES: The Healthcare Database Advanced Search interface developed by the National Institute of Health and Care Excellence was used to search MEDLINE, Embase, CINAHL, and CENTRAL. REVIEW METHODS: The systematic review complied with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines with the protocol registered in PROSPERO (CRD42020213121). Prognostic studies were considered comparing outcomes of patients with rAAA undergoing repair in high and low volume institutions or by high and low volume surgeons. Pooled estimates for peri-operative mortality were calculated using the odds ratio (OR) and 95% confidence intervals (CI), applying the Mantel-Haenszel method. Analysis of adjusted outcome estimates was performed with the generic inverse variance method. RESULTS: Thirteen studies reporting a total of 120 116 patients were included. Patients treated in low volume centres had a statistically significantly higher peri-operative mortality than those treated in high volume centres (OR 1.39; 95% CI 1.22 - 1.59). Subgroup analysis showed a mortality difference in favour of high volume centres for both endovascular aneurysm repair (EVAR; OR 1.61, 95% CI 1.11 - 2.35) and open repair (OR 1.50, 95% CI 1.25 - 1.81). Adjusted analysis showed a benefit of treatment in high volume centres for open repair (OR 1.68, 95% CI 1.21 - 2.33) but not for EVAR (OR 1.42, 95% CI 0.84 - 2.41). Differences in peri-operative mortality between low and high volume surgeons were not statistically significant for either EVAR (OR 1.06, 95% CI 0.59 - 1.89) or open surgical repair (OR 1.18, 95% CI 0.87 - 1.63). CONCLUSION: A high institutional volume may result in a reduction of peri-operative mortality following surgery for rAAA. This peri-operative survival advantage is more pronounced for open surgery than EVAR. Individual surgeon caseload was not found to have a significant impact on outcomes.