Endovascular Aneurysm Repair Patients Research Articles

Intravascular Iliac Artery Lithotripsy to Facilitate Aortic Endograft Delivery: Midterm Results of a Dual-Center Experience.

To assess the feasibility and safety of intravascular lithotripsy (IVL) for enabling transfemoral abdominal (EVAR), thoracic (TEVAR), and thoracoabdominal (BEVAR) endovascular aneurysm repair in patients with narrow and calcified iliac arteries. Consecutive patients treated with IVL for severe calcified and narrowed iliac access before EVAR, TEVAR, or BEVAR between November 2020 and June 2022 were retrospectively evaluated. All anatomical iliac characteristics were acquired by multi-planar reconstruction of preoperative computed tomography angiography (CTA). The hostility of the vascular accesses was classified based on Peripheral Arterial Calcium Scoring System (PACSS) and calcified access severity score (CASS), a new score considering both anatomical (calcium grade and length, minimum lumen diameter [MLD], and tortuosity index) and aortic stent-graft (SG/MLD index) parameters. Primary endpoint was technical success defined as successful aortic endograft delivery and deployment without iliac rupture. Freedom from complications and primary patency were additionally analyzed. Twenty-eight iliac axes were treated with IVL (8 bilateral) in 20 patients (mean age 74.5±6.7 years) with a mean follow-up of 26.5±6.2 (range 17-36) months. Ten patients underwent EVAR: 3 TEVAR, and 7 BEVAR procedures. In 14 patients (70%), aneurysm disease was associated with symptomatic aorto-iliac occlusive disease (AIOD), with Rutherford class III to IV. The PACSS was grade IV in 89% of the cases and the CASS (mean 14±2) was grade III to IV in all cases. The stent-graft (SG) outer diameter (5.60±1.65 mm) was significantly larger by 50% than MLD (3.96±1.20 mm), with an SG/MLD index of 1.50±0.51 (p<0.001). Technical success was 100%. No dissection, rupture, or distal embolization occurred. One (3.4%) bail-out stenting was necessary as endoconduit after IVL treatment. One month CTA showed that postoperative luminal gain increased by 93% (p<0.001). An improvement of 2 Rutherford classes occurred in all AIOD patients with a primary patency of 100% at last follow-up. This study shows the safety and feasibility of IVL as a valuable option to treat narrow and calcified iliac arteries to facilitate endograft delivery. Further studies will be useful to confirm these results. In this article, the use of intravascular iliac artery lithotripsy to facilitate aortic endograft delivery is explored. The presence of iliac severe calcifications still represents a contraindication for aortic endovascular repair. Intravascular lithotripsy increases the feasibility and safety of endovascular aortic procedures, facilitating endograft delivery and reducing the risk of iliac rupture and/or dissections by improving vessel compliance and luminal gain. This novel vessel preparation could be an alternative to "paving and cracking" and/or iliac conduits. This study describes a new score to classify the severity of iliac calcifications, considering anatomical parameters and the profile of aortic endografts delivery system.

Pros and Cons of Contrast-Enhanced Ultrasound in Endovascular Aneurysm Repair Surveillance

Endovascular Aneurysm Repair (EVAR) has become an increasingly popular treatment for abdominal aortic aneurysm. The success of this type of treatment is dependent upon, to great extent, appropriate post-procedure surveillance accurately recognises complications in a timely fashion. The prominent modes of surveillance have been Computed Tomography Angiography (CTA) and Color Duplex Ultrasound (CDUS). Each imaging method has its limitations; particularly the use of radiation and intravenous contrast media for the CTA and the subjectivity and lower resolution of the images that CDUS generates. More recently, Contrast-Enhanced Ultrasound (CEUS) has been used and provides an accurate diagnosis of many post-procedure complications. This study aims to review the literature and present the evidence for the role of CEUS in the surveillance of EVAR patients, which may have implications for future practice.

Locoregional Anesthesia Has Lower Risks of Cardiac Complications Than General Anesthesia After Prolonged Endovascular Repair of Abdominal Aortic Aneurysms

ObjectivesWhile general anesthesia is the primary anesthesia in endovascular aneurysm repair (EVAR), some studies suggested locoregional anesthesia could be a feasible alternative for eligible patients. However, most evidence was from retrospective studies and was subjected to an inherent selection bias that general anesthesia is often chosen for more complex and prolonged cases. To mitigate this selection bias, this study aimed to compare 30-day outcomes of prolonged non-emergent intact infrarenal EVAR in patients undergoing locoregional or general anesthesia. In addition, risk factors associated with prolonged operative time in EVAR were identified. Designretrospective large-scale national registry study. SettingAmerican College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) targeted database from 2012-2022 Participants4075 out of 16,438 (24.79%) patients had prolonged EVAR. Among patients with prolonged EVAR, 324 (7.95%) were under locoregional anesthesia. There were 3,751 (92.05%) under general anesthesia, where 955 of them were matched to the locoregional anesthesia cohort. InterventionsPatients undergoing infrarenal EVAR were included. Exclusion criteria included age<18 years, emergency cases, ruptured AAA, and acute intraoperative conversion to open. Only cases with prolonged operative times (>157 minutes) were selected. A 1:3 propensity-score matching was used to address demographics, baseline characteristics, aneurysm diameter, distant aneurysm extent, and concomitant procedures between patients under locoregional and general anesthesia. Thirty-day postoperative outcomes were assessed. Moreover, factors associated with prolonged EVAR were identified by multivariable logistic regression. Measurements and Main ResultsExcept for general anesthesia contraindications, patients undergoing locoregional or general anesthesia exhibited largely similar preoperative characteristics. After propensity-score matching, patients under locoregional and general anesthesia had a lower risk of myocardial infarction (0.93% vs 2.83%, p=0.04) but comparable 30-day mortality (3.72% vs 2.72%, p=0.35) and other complications. Specific concomitant procedures, aneurysm anatomy, and comorbidities associated with prolonged EVAR were identified. ConclusionsLocoregional anesthesia can be a safe and effective alternative to general anesthesia, particularly in EVAR cases with anticipated complexity and prolonged operative times, as it offers the potential benefit of reduced cardiac complications. Risk factors associated with prolonged EVAR can aid in preoperative risk stratification and inform the decision-making process regarding anesthesia choice.

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

ObjectiveThe 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. MethodsWe 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. ResultsOur 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. ConclusionsPatients 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.

Up and over staged endoconduit technique for endovascular aortic aneurysm repair

Adverse iliofemoral anatomy can preclude complex endovascular aortic aneurysm repair. This study aims to describe the “up-and-over” staged endoconduit technique to improve access and avoid vascular injury before complex endovascular aneurysm repair. A staged procedure for complex endovascular aortic aneurysm repair is performed using an endoconduit (W.L. Gore & Associates). After obtaining contralateral femoral access, the extension of iliofemoral disease is assessed using angiography. The endoconduit is advanced “up and over” the aortic bifurcation and delivered percutaneously into the common femoral artery to treat a diseased access site and maintain intact the ipsilateral femoral access for future stent graft deployment. Internal iliac artery patency is maintained when feasible. During complex aneurysm repair, the endoconduit is accessed directly under ultrasound guidance using sequential dilation to avoid vascular injury. PerClose sutures (Abbott Vascular) are used to close the endoconduit femoral access site. This study found that staged “up and over” endoconduit creation is a useful technique before complex endovascular aneurysm repair in patients with adverse iliofemoral anatomy. Avoiding accessing the main femoral access site during the first stage prevents vascular or access site injuries and allows for both iliac and femoral disease to be addressed.

Long-Term Outcomes of Endovascular Aneurysm Repair in Patients Aged ≤70 Years.

Objectives: The efficacy of endovascular aneurysm repair (EVAR) against abdominal aortic aneurysm (AAA) in younger patients remains unknown. Hence, the current study aimed to investigate whether the aneurysm-related mortality rate of EVAR is acceptable among patients aged ≤70 years. Methods: Among 644 patients, 148 underwent EVAR (EVAR group), and 496 received open surgical repair (OSR group). The cumulative incidence rates of aneurysm-related death, any intervention, and serious aneurysm-related events after AAA repair were evaluated using the cumulative incidence function in the presence of competing risks. Results: The EVAR group had higher prevalences of several comorbidities, and overall survival for the EVAR group was significantly inferior to that of the OSR group. The cumulative incidence rates of aneurysm-related death, any intervention, and serious aneurysm-related events at 5 years were 1.5%, 11.7%, and 6.4% in the EVAR group and 1.3%, 5.3%, and 5.9% in the OSR group, respectively. EVAR was not a significant prognostic factor of aneurysm-related mortality and serious aneurysm-related events. However, it was an independent poor prognostic factor of any intervention. Conclusion: EVAR was not a significant prognostic factor of aneurysm-related mortality and serious aneurysm-related events. Therefore, it demonstrated acceptable procedure-related long-term outcomes, at least in high-risk young patients.

Changes of vascular stiffness and central blood pressure after endovascular aneurysm repair in patients with hypertension. Results of one-year follow-up

Aim. To assess the changes of arterial stiffness, central blood pressure (CBP), and determine the factors potentially influencing them in patients with descending thoracic and abdominal aortic aneurysm, in combination with hypertension, one year after endovascular aneurysm repair ((T)EVAR).Material and methods. Patients ≥18 years of age without clinically significant cardiac arrhythmias were included. Before surgery and a year later, we determined peripheral blood pressure, heart rate (HR), CBP, augmentation index (AIx), pressure at the point of maximum rise of the direct pulse wave (PT1h), time to return of the reflected pressure wave (Tr) and carotid femoral pulse wave velocity (cfPWV).Results. Fifty patients were included (mean age, 68±9 years; 41 men; 16 with descending thoracic aortic aneurysm, 34 with abdominal aortic aneurysm), 23 patients were reexamined. After (T)EVAR, an increase in cfPWV (+2,6 m/s, p&lt;0,001), PT1h (+5 mm Hg, p=0,026), peripheral pulse pressure (+7 mm Hg, p=0,039), heart rate (+5 beats/min, p=0,025). The CBP and AIx values have not changed. The dependence of Tr decrease on the stent-graft length (β=0,42) and the decrease in heart rate (β=-0,52) was found. During the year, 6 cardiovascular events were registered.Conclusion. Graft implantation is accompanied by an increase in cfPWV, regardless of aneurysm location. An increase in PT1h one year after (T)EVAR may reflect a decrease in aortic distensibility and worsening damping function. No changes of CBP and AIx is probably explained by reflected wave characteristics after surgery. Predictors of Tr are — increase in heart rate and implantation of longer stent grafts.

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

Our objective was to investigate whether patients who receive anticoagulation therapy have different outcomes after endovascular aneurysm repair (EVAR) from those who do not. 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. 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. Anticoagulation is a poor prognostic factor after standard EVAR and should be considered in decision-making, consent processes, and surveillance strategies. 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.

One-year aneurysm-sac dynamics are associated with reinterventions and rupture following infrarenal endovascular aneurysm repair

ObjectiveOne-year aneurysm sac changes have previously been found to be associated with mortality and may have the potential to guide personalized follow-up following endovascular aneurysm repair (EVAR). In this study, we examined the association of these early sac changes with long-term reintervention and rupture. MethodsWe identified all patients undergoing first-time EVAR for intact abdominal aortic aneurysm between 2003 and 2018 in the Vascular Quality Initiative with linkage to Medicare claims for long-term outcomes. We included patients with an imaging study at 1 year postoperatively. Aneurysm sac behavior was defined as per the Society for Vascular Surgery guidelines: stable sac (<5 mm change), sac regression (≥5 mm), and sac expansion (≥5 mm). Outcomes included mortality, reintervention, and rupture within 8 years, which were assessed with Kaplan-Meier methods and multivariable Cox regression analysis. Secondarily, we utilized polynomial spline interpolation to demonstrate the continuous relationship of diameter change to 8-year hazard of reintervention, rupture, or mortality as a composite outcome. ResultsOf 31,185 EVAR patients, 16,102 (52%) had an imaging study at 1 year and were included in this study. At 1 year, 44% of sacs remained stable, 49% regressed, and 6.2% displayed expansion. Following risk adjustment, compared with a stable sac at 1 year, sac regression was associated with lower 8-year mortality (49% vs 53%; hazard ratio [HR], 0.92; 95% confidence interval [CI], 0.85-0.99; P = .036), reintervention rate (8.9% vs 15%; HR, 0.58; 95% CI, 0.50-0.68; P < .001), and rupture rate (2.0% vs 4.0%; HR, 0.45; 95%CI, 0.29-0.69; P < .001). Conversely, compared with a stable sac, sac expansion was associated with higher 8-year mortality (64% vs 53%; HR, 1.31; 95% CI, 1.14-1.51; P < .001) and reintervention rate (27% vs 15%; HR, 1.98; 95% CI, 1.57-2.51; P < .001), but similar risk of rupture (7.2% vs 4.0%; HR, 1.61; 95% CI, 0.88-2.96; P = .12). Polynomial spline interpolation demonstrated that, compared with no diameter change at 1 year, increased sac regression was associated with an incrementally lower risk of late outcomes, whereas increased sac expansion was associated with an incrementally higher risk of late outcomes. ConclusionsFollowing EVAR, compared with a stable sac at 1-year imaging, sac regression and expansion are associated with a lower and higher risk respectively of long-term mortality, reinterventions, and ruptures. Moreover, the amount of regression or expansion seems to be incrementally associated with these late outcomes, too. Future studies are needed to determine how to improve 1-year sac regression, and whether it is safe to extend follow-up intervals for patients with regressing sacs.

Post-Implantation Syndrome Incidence is Higher After Complex Endovascular Aortic Procedures Than After Standard Infrarenal Repair

Post-implantation syndrome (PIS), characterised by malaise, fever, and increased inflammatory markers, is a common occurrence after endovascular aneurysm repair (EVAR), causing prolonged hospitalisation and increased cost. This study aimed to determine the incidence and short-term outcomes of PIS after fenestrated or branched procedures in aorto-iliac aneurysms compared with standard EVAR. A retrospective, comparative study from a tertiary academic institution was undertaken. All patients who underwent elective EVAR with polyester stent grafts from January 2015 to June 2021 were considered. Two groups were defined: standard EVAR (sEVAR) and complex EVAR (cEVAR). The latter included visceral fenestrated and branched or iliac branch and chimney stent grafts. The primary outcome was the incidence of PIS within three days of the index procedure. Secondary outcomes were short-term complications and risk factors for PIS. A multivariable model was constructed to correct for confounders. Overall, 253 patients were included: 165 (65.2%) sEVAR and 88 (34.8%) cEVAR. Complex EVAR patients were younger, with larger aneurysms, had longer procedures, and were more likely to have intra-operative complications. The PIS incidence was 23.7% (n= 60), significantly higher in cEVAR (34.1% vs. 18.2%; p= .005) and increased with the complexity of the procedure (EVAR: 18.2% vs. EVAR+iliac branch device: 25.0% vs. fenestrated and branched EVAR: 36.2%; p= .030). On multivariable analysis, cEVAR (OR 2.833, 95% CI 1.295 - 6.198; p= .009) was associated with a significantly increased risk of PIS. No differences in short term outcomes according to PIS status were noted. Group sub-analysis for cEVAR patients did not reveal any statistically significantly different outcomes according to PIS occurrence. In this cohort, cEVAR procedures were associated with a significantly increased risk of developing PIS compared with standard infrarenal repair. Post-implantation syndrome also appears to have a benign course with no major impact on peri-operative outcomes after cEVAR. Further research to confirm these findings is required.

Circulating biomarkers of cardiovascular disease are related to aneurysm volume in abdominal aortic aneurysm.

Surveillance programs in abdominal aortic aneurysms (AAA) are mainly based on imaging and leave room for improvement to timely identify patients at risk for AAA growth. Many biomarkers are dysregulated in patients with AAA, which fuels interest in biomarkers as indicators of disease progression. We examined associations of 92 cardiovascular disease (CVD)-related circulating biomarkers with AAA and sac volume. In a cross-sectional analysis, we separately investigated (1) 110 watchful waiting (WW) patients (undergoing periodic surveillance imaging without planned intervention) and (2) 203 patients after endovascular aneurysm repair (EVAR). The Cardiovascular Panel III (Olink Proteomics AB, Sweden) was used to measure 92 CVD-related circulating biomarkers. We used cluster analyses to investigate protein-based subphenotypes, and linear regression to examine associations of biomarkers with AAA and sac volume on CT scans. Cluster analyses revealed two biomarker-based subgroups in both WW and EVAR patients, with higher levels of 76 and 74 proteins, respectively, in one subgroup versus the other. In WW patients, uPA showed a borderline significant association with AAA volume. Adjusting for clinical characteristics, there was a difference of -0.092 (-0.148, -0.036) loge mL in AAA volume per SD uPA. In EVAR patients, after multivariable adjustment, four biomarkers remained significantly associated with sac volume. The mean effects on sac volume per SD difference were: LDLR: -0.128 (-0.212, -0.044), TFPI: 0.139 (0.049, 0.229), TIMP4: 0.110 (0.023, 0.197), IGFBP-2: 0.103 (0.012, 0.194). LDLR, TFPI, TIMP4, and IGFBP-2 were independently associated with sac volume after EVAR. Subgroups of patients with high levels of the majority of CVD-related biomarkers emphasize the intertwined relationship between AAA and CVD.ClinicalTrials.gov Identifier: NCT03703947.

Side-by-side deployment of gore excluder legs at a narrow terminal aorta for endovascular aneurysm repair.

A narrow terminal aorta is a risk factor for endograft occlusion after endovascular aneurysm repair. To minimize limb complications, we used Gore Excluder legs positioned side-by-side at the terminal aorta. We investigated the outcomes of our strategy for endovascular aneurysm repair in patients with a narrow terminal aorta. We enrolled 61 patients who underwent endovascular aneurysm repair with a narrow terminal aorta (defined as < 18mm in diameter) from April 2013 to October 2021. The standard procedure involves complete treatment with the Gore Excluder device. When other types of main body endografts were used, they were deployed proximal to the terminal aorta, and we used the Gore Excluder leg device in the bilateral limbs. Postoperatively, the intraluminal diameter of the legs at the terminal aorta was measured to assess the configuration. During the follow-up period (mean: 2.7 ± 2.0years), there were no aorta-related deaths, endograft occlusions, or leg-related re-interventions. There were no significant differences between the pre- and postoperative ankle-brachial pressure index values in the dominant and non-dominant legs (p = 0.44 and p = 0.17, respectively). Postoperatively, the mean difference rate (defined as [dominant leg diameter-non-dominant leg diameter]/terminal aorta diameter) was 7.5 ± 7.1%. The difference rate was not significantly correlated with the terminal aortic diameter, calcification thickness, or circumferential calcification (r = 0.16, p = 0.22; r = 0.07, p = 0.59; and r = -0.07, p = 0.61, respectively). Side-by-side deployment of Gore Excluder legs produces acceptable outcomes for endovascular aneurysm repair with a narrow terminal aorta. The endograft expansion at the terminal aorta is tolerable without influencing calcification distribution.

Management of Retroperitoneal Fibrosis with Endovascular Aneurysm Repair in Patients Refractory to Medical Management

Early diagnosis and treatment of under-recognized retroperitoneal fibrosis (RPF) are essential before reaching the poorly responsive fibrotic stage. Although most patients respond to medical therapy, relapses are common. Open surgery in medically resistant patients is associated with major adverse clinical events. Therefore, we aim to compare the outcomes of endovascular repair in patients with RPF who were refractory to the optimal medical management. This is a single-center longitudinal study of optimal medical therapy (OMT) vs endovascular aneurysm repair (EVAR) in patients with RPF to our tertiary referral vascular center. Seventeen patients were referred to us with peri-aortic RPF over the study period. Eleven received OMT only, whereas six underwent EVAR after the failure of OMT. Eighty-two percent (n = 14) were male, and the mean follow-up was 74.40 ± 58.40 months. Nine (52%) had immunoglobulin G4-related disease (4 OMT vs 5 EVAR). EVAR patients had 100% technical success without perioperative mortality. Furthermore, all the EVAR patients were symptom-free following the intervention. Pre-operative aortic RPF index (maximum peri-aortic soft tissue diameter/maximum aortic diameter) was higher in the EVAR than in the OMT group. However, there was a significant decrement in the aortic RPF index following EVAR (P = .04). EVAR in RPF medical-resistant patients is a valuable option in the armamentarium of nephrologists and rheumatologists. Our study shows that an endovascular intervention provides a promising outcome in RPF/IgG4-RD periaortitis, which is refractory to medical therapy. We recommend further studies to investigate and establish the long-term effectiveness of endovascular repair in RPF.

Delays in Treatment Are Associated With Increased Mortality in Patients Undergoing Endovascular Repair of Abdominal Aortic Aneurysms

This study aims to evaluate the association between delays in treatment and outcomes after endovascular aneurysm repair (EVAR). A retrospective analysis of consecutive patients undergoing EVAR for abdominal aortic aneurysm (AAA) between January 1998 and December 2019 was performed. Patients undergoing early EVAR (within less than 8 weeks after meeting size threshold for repair) were compared with delayed EVAR (8 weeks or more). The primary outcome was freedom from all-cause mortality. Secondary outcomes were sac regression (defined as a reduction in AAA diameter by 5 mm or more), freedom from reinterventions, 30-day mortality, and complications. Variables were compared using the χ2 test or the Student t test as appropriate. Kaplan-Meier survival curves and Cox regression proportional hazards models were used. A P value of <.05 was considered significant. The study consisted of 513 patients (83% male) with 33% (n = 170) and 67% (n = 343) undergoing early and delayed EVAR, respectively. Early EVAR patients had a larger mean AAA diameter (60 ± 13 mm vs 54 ± 7 mm in delayed EVAR; P < .001). There were no major differences in medical comorbidities between the groups (Table). Operative timing was longer in the early group (119 ± 42 minutes vs 108 ± 45 minutes in delayed; P = .019). Kaplan-Meier survival estimates show that freedom from all-cause mortality was 90% in early EVAR vs 82% in delayed EVAR (P = .023; Fig) at a mean of 25.8 months. Sac regression was similar between the two groups at 54% and 45% for early and delayed EVAR, respectively (P = .304). In addition, freedom from reinterventions was 78% in early EVAR and 83% in delayed EVAR (P = .364). Perioperative mortality was 0% in both groups. Perioperative complication rates were similar at 11% and 9% in early and delayed EVAR, respectively. The Cox regression proportional hazards model showed that delayed EVAR predicted increased mortality (hazard ratio: 1.886, 95% confidence interval [CI]: 1.083-3.285; P = .025). The effect persisted after adjusting for age, AAA diameter, and comorbidities (hazard ratio: 2.597, 95% CI: 1.350-4.998; P = .004). Patient undergoing EVAR within less than 8 weeks after meeting indications for repair tend to have larger aneurysms. Delaying EVAR beyond 8 weeks was associated with increased all-cause mortality after adjusting for preoperative AAA diameter, age, and comorbidities. These findings suggest the need to adopt a pathway that permits expedited treatment within 8 weeks of meeting indications for repair.TableBaseline characteristics of early and delayed EVAR patientsCharacteristicEarlyDelayedP valueAge, mean (SD), years77 (8)77 (8).873Male sex, % (No.)87 (147)80 (275).090Mean AAA diameter, mean (SD), mm60 (13)54 (7)<.001Comorbidities, % (No.) Cardiac37 (63)37 (127).994 Respiratory21 (36)25 (87).296 Hemodialysis01 (4).157 HTN48 (82)55 (189).143 DM12 (20)15 (50).382 Dyslipidemia47 (79)56 (191).049 PAD11 (18)10 (34).811 Active or previous cancer14 (23)11 (36).316 Active smoking15 (24)20 (66).137Medications, % (No.) β-Blockers31 (52)34 (116).437 ACEI/ARB24 (41)34 (116).022 CCB18 (30)21 (73).326 Statin41 (70)53 (182).010 Antiplatelets38 (65)51 (175).006 Anticoagulation11 (19)11 (36).815AAA, Abdominal aortic aneurysm; ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin receptor blocker; CCB, calcium channel blockers; DM, diabetes mellitus; EVAR, endovascular aortic repair; HTN, hypertension; PAD, peripheral arterial disease. Open table in a new tab

Long-term outcomes of the Endurant endograft in patients undergoing endovascular abdominal aortic aneurysm repair

Objective/BackgroundTo investigate the long-term outcomes after endovascular aneurysm repair (EVAR) in a real-world setting using the Endurant endograft (EG). Methods184 EVAR candidates treated with the Endurant family EGs in a single vascular center were prospectively enrolled from January 2009 to December 2016. Kaplan-Meir estimates of long-term standardized primary and secondary outcome measures were performed. Per protocol, subgroup comparison analysis was performed in three groups: patients treated within instructions for use (in-IFU) vs patients treated outside IFU (outside-IFU), EVAR in patients receiving the Endurant proximal diameter 32 or 36 mm EG vs those receiving the <32 mm diameter EG and EVAR with various Endurant EG versions. ResultsThe mean follow-up was 75.09 ± 37.9 months (range: 4.1-172 months). The median age of the patients was 72.96 ± 7.03 years (range: 55-88 years). A total of 177 patients were male (96.2%). Compliance with IFU was followed in 107 patients (58.2%). Overall survival was 69.5% and 48% at 5 and 8 years, respectively. Of the 102 all-cause deaths, 7 (6.9%) were aneurysm related. Six of these postimplant deaths occurred in patients presented with aneurysm rupture from type Ia or/and type Ib endoleak. At 5, 8, and 10 years of observation, freedom from aneurysm rupture, open surgical conversion, type I/III endoleak, any type of endoleak, aneurysm-related secondary intervention probabilities, and neck-related events were as follows: 98.1%, 95%, and 89.4%; 95.1%, 91.2%, and 85.7%; 93.6%, 87.3%, and 83.9%; 83.4%, 74%, and 70.9%; 89.8%, 76.7%, and 72%; and 96.3%, 90%, and 87.6%, respectively. Corresponding clinical success was 90%, 77.4%, and 68.4%, respectively. Patients treated outside-IFU had significantly higher risk of aneurysm rupture, open surgical conversion probability, occurrence of type I/III endoleak, and chance of reinterventions and lower clinical success probabilities compared with the in-IFU counterparts at 5 and 8 years. This statistical difference remained when type Ia endoleak or endoleak of any type was considered independently. In addition, it was stronger in patients having extreme anatomic boundaries (>1 hostile anatomic condition), when aneurysm-related death, aneurysm rupture, and clinical success at 5 years were considered. Overall proximal migration and limb occlusion were recorded in 1.1% and 4.9% of the patients, respectively. Overall reintervention rate was 17.4%. An increase in aneurysm sac diameter was observed in 12.5% of patients and was not related to IFU status. The Endurant version or the proximal EG diameter had no significant association with the chance of any complication or adverse event. ConclusionsThe data confirmed the durability of the Endurant EG, achieving promising long-term outcomes in a real-world setting. However, its positive performance must be interpreted with caution in patients treated off-label especially those with extreme anatomic boundaries. In this cohort, some of EVAR advantages might be lost in the late future. Further similar studies are warranted.

Abstract 353: Management Of Retroperitoneal Fibrosis With Endovascular Aneurysm Repair In Patients Refractory To Medical Management

Background: Early diagnosis and treatment of under-recognized retroperitoneal fibrosis (RPF) are essential before reaching the poorly responsive fibrotic stage. Although most patients respond to medical therapy, relapses are common. Open surgery in medically resistant patients is associated with major adverse clinical events. Therefore, we aim to compare the outcomes of endovascular repair in RPF patients who were refractory to the optimal medical management. Methods: This is a single-centre longitudinal study of optimal medical therapy (OMT) vs endovascular aneurysm repair (EVAR) in patients with RPF to our tertiary referral vascular centre. Results: Seventeen patients were referred to us with peri-aortic RPF over the study period. Eleven received OMT only, while six underwent EVAR after the failure of OMT. Eighty-two percentages (n=14) were male, and the mean follow-up was 74.40 ± 58.40 months. Nine (52%) had immunoglobulin G4-related disease (4 OMT vs 5 EVAR). EVAR patients had 100% technical success without perioperative mortality. Furthermore, all the EVAR patients were symptom-free following the intervention. Pre-operative aortic RPF index (maximum peri-aortic soft tissue diameter/maximum aortic diameter) was higher in the EVAR than in OMT. However, there was a significant decrement in the aortic RPF index following EVAR (p=0.04). Conclusion: EVAR in RPF medical-resistant patients is a valuable option in the armamentarium of nephrologists and rheumatologists. Our study shows that an endovascular intervention provides a promising outcome in RPF/IgG4-RD periaortitis, which is refractory to medical therapy. We recommend further studies to investigate and establish the long-term effectiveness of endovascular repair in RPF.

Abstract 522: Computational Fluid Dynamics Analyses Of Geometric Incompatibility And Seal Zone Stability In Endovascular Aneurysm Repair

Introduction: Long-term durability of endovascular aneurysm repair (EVAR) is often compromised due to inadequate sealing of the endograft to the aorta. We hypothesize that geometric mismatch between the aorta and endograft can lead to the development of bird-beak regions, type Ia endoleaks, and endograft migration. Our novel computational model shows how geometric incompatibility at the seal zone contributes to endoleak formation and propagation. Methods: Using finite-element modeling, we simulated endograft crimping and deployment in pressurized aortic models with different degrees of curvature (0°, 30°, 60°) and oversizing (0%, 20%, 25%). We then performed computational fluid dynamics (CFD) modeling with a detailed pressure analysis of various regions along the length of each model. Results: Across our models, pressure gradients developed between the bulk flow and endoleak regions. For all degrees of curvature, the average total pressure in the endoleak region was higher than that of the bulk flow in the 20% and 25% oversized models. While oversizing decreased the aorta-endograft geometric mismatch in the 60° model and mitigated the volume of endoleak, too much oversizing in the 0° models worsened endoleak. Conclusions: We present one of the first computational models to study the sensitivity of seal zone mechanics to the degree of aorta-endograft mismatch. Our finding of pressure gradients that exist between the endoleak and bulk flow may represent regions of high mechanical instability that may further propagate the endoleak. Our results highlight the importance of shape and oversizing considerations when selecting the appropriate endovascular therapy for EVAR patients. Figure 1: CFD simulations of aorta-endograft models with different degrees of curvature and oversizing show endoleak formation as a function of geometric incompatibility.

Assessing Endovascular Aneurysm Repair Suitability According to Graft-Specific Instructions for Use in Patients With a Ruptured Abdominal Aortic Aneurysm

The purpose of the study is to ascertain endovascular aneurysm repair (EVAR) suitability in relation to stent-graft-specific instructions for use (IFU) in patients with a ruptured abdominal aortic aneurysm (RAAA). Using the preoperative computed tomography angiography (CTA), the aortic morphology of patients undergoing surgical repair of a RAAA in 2 Dutch hospitals between January 2014 and December 2019 was retrospectively assessed. Three-dimensional and central luminal line reconstructions were used. Anatomical suitability was defined according to the IFU of the stent graft system used. Of 128 included patients, 112 (88%) were men and the mean age was 74.1 (SD=7.6) years. Anatomy within IFU for EVAR was present in 31 patients (24%). Overall, 94 patients (73%) were treated with open surgical repair (OSR) and 34 patients (27%) were treated with EVAR. Anatomy within IFU was present in 15 OSR patients (16%) and 16 EVAR patients (47%). In patients with anatomy outside of IFU, 90% (87/97) had unsuitable neck anatomy and 64% (62/97) had insufficient neck length. An unsuitable distal iliac landing zone was observed in 35 patients. Perioperative mortality was 27% (34/128), with no difference between OSR and EVAR (25/94 vs 9/34; p=0.989). Most RAAA patients in this series did not have aortic anatomy within IFU for EVAR, mainly due to insufficient neck length. However, whether anatomy outside of IFU equates to unsuitability for EVAR in an emergency setting remains a matter of debate and warrants further research. The treatment of a ruptured abdominal aortic aneurysm can consist of endovascular repair or open repair. Retrospective anatomical assessment shows that most patients do not have anatomy inside the instructions for use for endovascular aneurysm repair, mainly due to insufficient neck length. Whether anatomy outside the instructions for use equates unsuitability for endovascular aneurysm repair remains a matter of debate.

A computational fluid dynamics model of seal zone stability in endovascular aneurysm repair

Aortic aneurysms are pathological dilations of the aorta due to a weakened vessel wall that can quickly become fatal if ruptured. One option for surgical intervention is to perform endovascular aneurysm repair (EVAR) which consists of deploying an expandable endograft across the aneurysm so that blood is redirected through the lumen of the endograft rather than permitted to flow into the aneurysmal sac to cause further pressurization and dilation. The endograft relies upon non-surgical adhesion to the aortic wall at its seal zone to fix the device in place. While EVAR has shown favorable short-term outcomes, long-term durability is impaired due to instability at the seal zone. Specifically, endoleaks often develop in the gap between the undersurface of the stent graft and the vessel wall--termed the bird-beak region--and are clinically presumed to be due to a mismatch between the geometry of the aorta and the endograft. However, we currently lack a rigorous biomechanical understanding of how this geometric incompatibility contributes to endoleak formation and propagation. To investigate the stability of seal zone mechanics, we simulated endograft deployment in computational models of idealized aortic models with different degrees of curvature to replicate bird-beak regions of various sizes. We will then perform computational fluid dynamics (CFD) analyses to characterize the fluid behavior and pressure profile at the seal zone as a function of increasing bird-beak size. These first steps will form the foundation for our future studies where we aim to couple CFD with fluid-structure-fracture simulations to more robustly model the mechanics of endoleaks. By harnessing the power of computational methods, our project seeks to deepen our biomechanical understanding of how endograft selection may affect device failure rates in EVAR patients.

Frailty Among Veterans Undergoing Abdominal Aortic Aneurysm Repair

Frailty is a known risk factor for adverse outcomes following surgery and affects at least 3 of every 10 US Veterans aged 65years and older. We designed a study to characterize the association between frailty and complications after endovascular aneurysm repair (EVAR) compared to open aneurysm repair (OAR) at our regional Veterans Affairs Medical Center. Veterans who underwent either OAR or EVAR at our institution between January 1, 2000 and December 31, 2020 were identified. We examined medical history, procedure characteristics, perioperative complications, and frailty as measured by the 5-factor modified frailty index (mFI-5). Frailty was defined as an mFI-5 score ≥2. Primary endpoints were postoperative complications, duration of surgery, and length of hospital stay. Tests of association were performed with t-test and chi-squared analysis. Over the 21-year period, we identified 314 patients that underwent abdominal aortic aneurysm (AAA) repair with 115 (36.6%) OAR and 199 EVAR (63.4%) procedures. Patients undergoing EVAR were older on average (72.1years vs. 70.2years) and had a higher average mFI-5 compared to the open repair group (1.49 vs. 1.23, P=0.036). When comparing EVAR and OAR cohorts, patients undergoing OAR had a larger AAA diameter (6.5cm, standard deviation [SD]: 1.5) compared to EVAR (5.5cm, SD: 1.1 P<0.0001). Fewer frail patients underwent OAR (n=40, 34.8%) compared to EVAR (n=86, 43.2%), and frail EVAR patients had higher AAA diameter (5.8cm, SD: 1.0) compared to nonfrail EVAR patients (5.3cm, SD 1.2), P=0.003. Among OAR procedures, frail patients had longer operative times (296min vs. 253min, P=0.013) and higher incidence of pneumonia (17.5% vs. 5.3%, P=0.035). Among frail EVAR patients, operative time and perioperative complications including wound dehiscence, surgical site infection, and pneumonia were not significantly different than their nonfrail counterparts. Overall, frail patients had more early complications (n=55, 43.7%) as compared to nonfrail patients (n=48, 25.5%, P=0.001). OAR patients had higher rates of postoperative complications including wound dehiscence (7.0% vs. 0.5%, P=0.001), surgical site infections (7.0% vs. 1.0%, P=0.003), and pneumonia (9.6% vs. 0.5%, P=<0.0001). Open repair was also associated with overall longer average intensive care unit stays (11.0days vs. 1.6days, P<0.0001) and longer average hospitalizations (13.5days vs. 2.4days, P<0.0001). Our findings demonstrate that frailty is associated with higher rates of adverse outcomes in open repair compared to EVAR. Patients who underwent open repair had higher rates of wound dehiscence, surgical site infection, and pneumonia, compared to those undergoing endovascular repair. Frailty was associated with larger AAA diameter in the EVAR cohort and longer operative times, with higher frequency of postoperative pneumonia in the OAR cohort. Frailty is a strong risk factor that should be considered in the management of aortic aneurysms.