Frequency and Outcome of Re-interventions after Endovascular Repair for Abdominal Aortic Aneurysm: A Prospective Cohort Study

Aortoenteric Fistulas Following Endovascular Aortic Aneurysm Repair: A Review

BackgroundSecondary aortoenteric fistulas (SAEF) following endovascular aortic repair (EVAR) is an extremely rare event but life threatening. Our review offers comprehensive knowledge on pathophysiology, clinical presentation, diagnosis, and treatment options.AimTo summarize the current literature regarding pathophysiology, clinical, diagnostic and therapeutic approach of aortoenteric fistulas secondary to EVAR.MethodsWe performed a literature search in Pubmed/MEDLINE to identify the literature published about SAEF after EVAR. Cases were summarized in a table and prevalences. Other relevant literature was included in the results sections.ResultsA total of 35 reports (single cases and small series) with 45 patients were included. SAEF after EVAR can result from infection, inflammation, or mechanical factors. Clinical presentation is often non-specific, ranging from a gastrointestinal herald bleed to hemorrhagic shock, or malaise and general infection-related symptoms. Cross-sectional imaging plays a critical role in diagnosing SAEF. The treatment approach involves a multidisciplinary team approach and requires broad-spectrum intravenous antibiotics, endovascular intervention for urgent hemorrhage control, and open surgical intervention for definitive repair. Long-term antimicrobial therapy is essential to avoid reinfection.ConclusionsSAEF following EVAR represents a complex, life-threatening condition with limited evidence-based management strategies. Given the growing prevalence of endovascular procedures, comprehensive knowledge of SAEF is crucial for all health care providers to improve early diagnosis and outcomes.

Does Functional Status Predict Worse 30-D Outcomes in Endovascular Repair of Abdominal Aortic Aneurysms? A Propensity-Score Matched Study From ACS-NSQIP Targeted Database From 2012 to 2022

INTRODUCTION

In patients undergoing endovascular aneurysm repair (EVAR), existing studies have identified an association between dependent functional status (DFS) and poorer outcomes after EVAR. However, noted limitations, especially the lack of differentiation between ruptured and nonruptured abdominal aortic aneurysm (AAA), potentially affect the extrapolation of these findings to specific patient groups. Thus, this study aimed to evaluate the association between functional status and 30-d outcomes after EVAR in ruptured and nonruptured AAA patients separately.

METHODS

Patients who underwent infrarenal EVAR were identified in the American College of Surgeons National Surgical Quality Improvement Program targeted database from 2012-2022. Patients with DFS and those with independent functional status (IFS) were stratified into the two study cohorts. In nonruptured AAA, a 1:1 propensity-score matching was used to address demographics, baseline characteristics, aneurysm diameter, distal extent of the aneurysm, anesthesia, and concomitant procedures between patients with DFS and IFS. The sample size for ruptured patients with AAA was too small for meaningful statistical analysis so only qualitative description was provided. Thirty-d postoperative mortality and morbidities of EVAR were assessed.

RESULTS

For nonruptured cases, there were 380 (2.55%) DFS and 14,545 (97.45%) patients with IFS, where 453 patients with IFS were matched to the DFS cohort. For ruptured AAA, there were 17 (6.39%) DFS and 249 (93.61%) IFS. After matching, nonruptured DFS and patients with IFS had similar 30-d mortality rates (2.37% vs 2.11%, P = 1.00). However, patients with DFS had a higher risk of bleeding requiring transfusion (18.42% vs 11.84%, P = 0.01) and longer length of stay (median 3.00 [Q1 1.00, Q3 6.00] vs median 2.00 [Q1 1.00, Q3 4.00] d, P < 0.01). All other outcomes, including major adverse cardiovascular events, cardiac complications, stroke, pulmonary complications, renal complications, sepsis, venous thromboembolism, wound complications, lower extremity ischemia, ischemic colitis, postoperative ruptured aneurysm, unplanned reoperation, 30-d readmission, were not different between patients with DFS and IFS. Qualitatively, ruptured patients with DFS had higher crude rates of 30-d mortality and morbidities compared to patients with IFS.

CONCLUSIONS

Contrary to previous literature, patients with DFS with nonruptured AAA undergoing EVAR were found to have largely comparable outcomes to patients with IFS, although extra attention should be paid to postoperative bleeding.

Acute Intraoperative Conversion from Endovascular to Open vs Planned Open Operation for Abdominal Aortic Aneurysm: A Propensity-Score Matched Study from the American College of Surgeons NSQIP-Targeted Database

BACKGROUND

Evaluating outcomes for acute intraoperative conversion to open surgery during endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) was difficult due to low incidence. This study aimed to compare 30-day outcomes between patients with acute intraoperative conversion during EVAR and planned open surgery, and to identify risk factors associated with acute conversion.

STUDY DESIGN

Patients who underwent EVAR or planned open AAA repair were identified in American College of Surgeons NSQIP-targeted databases from 2012 to 2021. Patients with acute intraoperative conversion during EVAR were selected. A 1:3 propensity-score matching was used to match demographics, baseline characteristics, surgical indications, aneurysm size and extent, and emergency cases between the conversion open and planned open groups. Thirty-day postoperative outcomes were assessed.

RESULTS

Of 20,566 EVAR cases, 177 (0.86%) had acute intraoperative conversion to open surgery. The conversion open group was matched to 504 of 5,249 planned open patients. Conversion open and planned open groups had comparable 30-day mortality (23.43% vs 17.46%, p = 0.09) and organ system complications, including major adverse cardiovascular event (14.86% vs 10.71%, p = 0.17), pulmonary complications (17.71% vs 24.01%, p = 0.09), and renal complications (8.57% vs 11.11%, p = 0.39). The conversion open group had lower bleeding requiring transfusion (48.57% vs 75.60%, p < 0.01), shorter operation time (p < 0.01), and shorter length of stay (p < 0.01). Other postoperative outcomes did not differ. Risk factors associated with acute intraoperative conversion included ruptured aneurysm with or without hypotension. Protective factors included hypertension and aortic distal aneurysm extent.

CONCLUSIONS

Although this study does not endorse a universal "EVAR first" strategy for all patients with AAA, EVAR can be attempted first in eligible patients with AAA. Even when EVAR is unsuccessful, intraoperative conversion to open surgery still appears to be safe compared with planned open repair.

Aortic Endograft Infection: Diagnosis and Management

Aortic endograft infection (AEI) is a rare but life-threatening complication of endovascular aneurysm repair (EVAR). The clinical features of AEI range from generalized weakness and mild fever to fatal aortic rupture or sepsis. The diagnosis of AEI usually depends on clinical manifestations, laboratory tests, and imaging studies. Management of Aortic Graft Infection Collaboration (MAGIC) criteria are often used to diagnose AEI. Surgical removal of the infected endograft, restoration of aortic blood flow, and antimicrobial therapy are the main components of AEI treatment. After removing an infected endograft, in situ aortic reconstruction is often performed instead of an extra-anatomic bypass. Various biological and prosthetic aortic grafts have been used in aortic reconstruction to avoid reinfection, rupture, or occlusion. Each type of graft has its own merits and disadvantages. In patients with an unacceptably high surgical risk and no evidence of an aortic fistula, conservative treatment can be an alternative. Treatment results are determined by bacterial virulence, patient status, including the presence of an aortic fistula, and hospital factors. Considering the severity of this condition, the best strategy is prevention. When encountering a patient with AEI, current practice emphasizes a multidisciplinary team approach to achieve an optimal outcome.

Contemporary incidence, outcomes, and survival associated with endovascular aortic aneurysm repair conversion to open repair among Medicare beneficiaries

OBJECTIVE

The widespread application of endovascular abdominal aortic aneurysm repair (EVAR) has ushered in an era of requisite postoperative surveillance and the potential need for reintervention. The national prevalence and results of EVAR conversion to open repair, however, remain poorly defined. The purpose of this analysis was to define the incidence of open conversion and its associated outcomes.

METHODS

The SVS Vascular Quality Initiative EVAR registry linked to Medicare claims via Vascular Implants Surveillance and Interventional Outcomes Network was queried for open conversions after initial EVAR procedures from 2003 to 2016. Cumulative conversion incidence within up to 5 years after EVAR and outcomes after open intervention were determined. Multivariable logistic regressions were used to identify independent predictors of conversion and mortality.

RESULTS

Among 15,937 EVAR patients, 309 (1.9%) underwent an open conversion: 43% (n = 132) early (<30 days) and 57% (n = 177) late (>30 days). The longitudinally observed rate of conversion was constant over time, as well as by geographic region. Independent predictors of conversion included female sex (hazard ratio [HR], 1.49; P < .001), aneurysm diameter or more than 6.0 cm at the time of index EVAR (HR, 1.74; P < .001), nonelective repair (compared with elective presentation: HR, 1.72; P < .001), and aortouni-iliac repairs (HR, 2.19; P < .001). In contrast, adjunctive operative procedures such as endo-anchors or cuff extensions (HR, 0.62; P = .06) were protective against long-term conversion. Both early (HR, 1.6; P < .001) and late (HR, 1.26; P = .07) open conversions were associated with significant 30-day (total cohort, 15%) and 1-year mortality (total cohort, 25%). Patients undergoing open conversion experienced high rates of 30-day readmission (42%) and cardiac (45%), renal (32%), and pulmonary (30%) complications.

CONCLUSIONS

This large, registry-based analysis is among the first to document the incidence and outcomes for open conversion after EVAR in a national cohort with long-term follow-up. Importantly, women, patients with large aneurysms, and complex anatomy, as well as urgent or emergent EVARs are at an increased risk for open conversion. It seems that more conversions are performed in the early postoperative period, despite perceptions that conversion is a delayed phenomenon. In all instances, conversion is associated with significant morbidity and mortality and highlights the importance of appropriate patient selection at the time of index EVAR.

Comparison of Outcomes Following EVAR Based on Aneurysm Diameter and Volume and Their Postoperative Variations

PURPOSE

to evaluate the impact of bi- and 3-dimensional preoperative aortic morphological features and their immediate postoperative variations on the outcome of abdominal aortic aneurysms (AAA) treated by endovascular exclusion with standard devices (EVAR).

MATERIALS AND METHODS

Double centre retrospective analysis of prospectively collected registry data of EVAR patients. For all patients, preoperative and 30-day computed tomographic angiography images (CTA) were reviewed. Preoperative maximum AAA diameter >59 mm and volume >159 cm³, and any 30-day postoperative increasing at CTA, were considered as potentially influencing the outcome. The outcome measures were: primary technical success; 30-day, 1-year, and mean follow-up reintervention, all-cause and AAA-related mortality rates, and also endoleak-related reinterventions.

RESULTS

Three hundred and thrity-three patients were enrolled. Mean preoperative and 30-day AAA diameter and volume were 50.4 mm ± 11.8 vs. 49.1 mm ± 12.1, and 112.9 cm3 ± 79.5 vs. 112.1 cm3 ± 80.5, respectively. Primary technical success was achieved in all cases. At 34.9 months follow-up, cumulative reintervention rate was 12.0%, mortality rates 7.2%, without AAA-related deaths. Endoleak-related reintervention rate was 7.5%. At uni- and multi-variate analysis, preoperative AAA diameter >59 mm, and AAA volume >159 cm³ were significantly associated to reintervention (P = 0.012; P = 0.002), and reintervention and death (P = 0.002; P = 0.001) during follow-up. Additionally, any increase in postoperative AAA diameter or volume was significantly associated with reintervention (P = 0.001, P = 0.001) and reintervention and death (P = 0.006, P = 0.001). Endoleak-related reintervention were also significantly associated with all of the analysed morphological parameters (P = 0.019, P = 0.005, P = 0.005, and P = 0.002, respectively).

CONCLUSIONS

Patients with larger baseline AAA size and volume as well as unfavourable early remodelling of the sac are associated to worse long-term EVAR outcome.

State of the art and meta-analysis of secondary open aortic procedure after abdominal endovascular aortic repair

BACKGROUND

Secondary open aortic procedures (SOAP) treat complications of endovascular aneurysm repair, when further endovascular options are exhausted. We aimed at depicting the state of the art of SOAP with high-level evidence.

METHODS

A systematic review of the SOAP literature, with a meta-analysis of its outcomes (primary outcome operative mortality; secondary outcome major morbidity) and metaregression of risk factors for mortality (PROSPERO 42017075631).

RESULTS

Twenty-eight studies (1093 patients) were elected for analysis. SOAP was performed within the same hospitalization of or 30 days from domestic endovascular aneurysm repair (early SOAP) in 0.2% of the patients (85/40,256), and in a nonelective setting in 24.3% (95% confidence interval, 21.8-26.9). Most frequent indications were endoleak (44.4%; 95% confidence interval, 41.4-47.3) and rupture (12.7%; 95% confidence interval, 10.4-15.1). The most common procedures were infrarenal aortic replacement (85.2%; 95% confidence interval, 82.6-87.7) with high use of supravisceral clamping (suprarenal, 25% [95% confidence interval, 21.9-28.1] and supraceliac, 20.7% [95% confidence interval, 17.8-23.6]), and axillobifemoral bypass with stent explant (6.9%; 95% confidence interval, 5.1-8.7). Operative mortality (in-hospital or 30-day) was 10.9% (95% confidence interval, 8.7-13.5). The most frequent morbidities were respiratory (11.4%; 95% confidence interval, 8.1-15.9) and renal (9.5%; 95% confidence interval, 8.1-15.9). Risk factors for mortality were supravisceral clamping (Z = 3.007; Q = 9.044; P = .003) and nonelective status (Z = 3.382; Q = 11.440; P = .001).

CONCLUSIONS

Endoleak is the main indication for SOAP, which mostly consists of infrarenal aortic replacement. Risk factors for operative mortality are nonelective status and supravisceral clamping.

Endograft Infection After Endovascular Abdominal Aortic Aneurysm Repair: A Systematic Review and Meta-analysis

Purpose: To report a meta-analysis of the published evidence on the outcomes of aortic endograft infection after endovascular aneurysm repair (EVAR). Methods: A search of electronic information sources (PubMed/MEDLINE, SCOPUS, CENTRAL) and bibliographic reference lists identified 12 studies reporting on 362 patients (mean age 72 years; 279 men). The methodological quality of the selected studies was assessed using the Newcastle-Ottawa scale. Endpoints were 30-day/in-hospital mortality and follow-up mortality. Pooled estimates are reported with the 95% confidence interval (CI). The review was registered at the International Prospective Register of Systematic Reviews in Health and Social Care (CRD42016034166). Results: The incidence of graft infection after EVAR was 0.6% (95% CI 0.4% to 0.8%). The time from implantation to diagnosis ranged from 1 to 128 months (mean 25). The majority of patients (293, 81%) underwent surgical treatment (95% CI 77% to 83%); 9 (2.5%) patients (95% CI 21% to 43%) received conservative treatment. Aortic replacement with a prosthetic graft was performed in 58% (95% CI 52% to 62%), whereas cryopreserved allografts and autologous grafts were used in 31% (95% CI 28% to 33%) and 11% (95% CI% 8 to 14%), respectively. Less than half of the patients (40%) had emergency surgery. The pooled estimate of 30-day/in-hospital mortality was 26.6% (95% CI 16.9% to 39.2%). The pooled 30-day/in-hospital mortality for 9 patients treated conservatively was 63.3% (95% CI 30.7% to 87.0%). The pooled overall follow-up mortality was 45.7% (95% CI 36.4% to 55.4%) vs 58.6% (95% CI 28.8% to 83.3%) for the 9 patients receiving conservative treatment. Conclusion: Aortic endograft infection is a rare complication after EVAR. Surgical treatment with complete explantation of the infected endograft seems to be the optimal management in selected patients. Supportive medical treatment without surgical intervention has a significant associated mortality.

Conversion from endovascular to open abdominal aortic aneurysm repair

BACKGROUND

Previous studies have found conflicting results regarding the operative risks associated with conversion to open abdominal aortic aneurysm (AAA) repair after failed endovascular treatment (endovascular aneurysm repair [EVAR]). The purpose of this study was to assess the outcome of patients undergoing a conversion, and compare outcomes with standard open AAA repair and EVAR. In addition, we sought out to identify factors associated with conversion.

METHODS

All patients undergoing a conversion to open repair, and those undergoing standard EVAR and open repair between 2005 and 2013 were included from the National Surgical Quality Improvement Program. Multivariable logistic regression analysis was used to identify factors associated with conversion, and to assess independent perioperative risks associated with conversion compared with standard AAA repair. Subanalysis for factors associated with conversion was performed among patients additionally included in the more detailed targeted vascular module of the National Surgical Quality Improvement Program.

RESULTS

A total of 32,164 patients were included, with 300 conversions, 7188 standard open repairs, and 24,676 EVARs. Conversion to open repair was associated with a significantly higher 30-day mortality than standard open repair (10.0% vs 4.2%; odds ratio [OR], 2.4; 95% confidence interval [CI], 1.6-3.6; P < .001), and EVAR (10.0% vs 1.7%; OR, 7.2; 95% CI, 4.8-10.9; P < .001). Conversion surgery was additionally followed by an increased occurrence of any complication (OR, 1.5; 95% CI, 1.2-1.9 [open]; OR, 7.8; 95% CI, 6.1-9.9 [EVAR]). Factors associated with conversion were young age (OR, 1.2 per 10 years decrease; 95% CI, 1.1-1.4), female gender (OR, 1.5; 95% CI, 1.2-2.0), and nonwhite race (OR, 1.8; 95% CI, 1.3-2.6). Conversely, body mass index >30 was negatively associated with (OR, 0.7; 95% CI, 0.5-0.9). Among anatomic characteristics captured in the targeted vascular data set (n = 4555), large aneurysm diameter demonstrated to be strongly associated with conversion (OR, 1.1 per 1 cm increase; 95% CI, 1.03-1.1).

CONCLUSIONS

Conversion to open repair after failed EVAR is associated with substantially increased perioperative morbidity and mortality compared with standard AAA repair. Factors associated with conversion are large diameter of the aneurysm, young age, female gender, and nonwhite race, whereas obesity is inversely related to conversion surgery.

Clinical Outcome and Technical Considerations of Late Removal of Abdominal Aortic Endografts: 8-Year Single-Center Experience

During an 8-year period, 355 patients underwent endovascular repair of mainly true (97%) infrarenal aneurysms. After a mean follow-up of 48 months, 11 (3.1%) patients required conversion to open repair and 10 were eligible for open surgical intervention. Via a midline incision, explantation of the endograft was performed by using an infrarenal aortotomy. Explantation was done for rupture in four patients (40%), with a marked difference in mortality rates between acute (50%) and elective (0%) explantations.

The main reason for explantation was proximal type I endoleak caused by (1) malposition of the device, (2) proximal migration of the endograft, and (3) dislodgment of a tube endograft that followed former central reconstruction. Proximal migration is most worrisome and demands preventive endovascular reintervention.

The mortality and morbidity rates of elective explantation are acceptable. When delayed conversion is indicated, priority has to be given to operate on these patients.

Open Surgical Treatment of Aneurysmal Sac Expansion following Endovascular Abdominal Aneurysm Repair: Solution for an Unresolved Clinical Dilemma

The advantages of endovascular aneurysm repair (EVAR) are probably related to the avoidance of the three major physiological insults associated with open abdominal aortic aneurysm (AAA) repair: laparotomy, aortic cross-clamping and ischemia reperfusion injury. Continuing aneurysm expansion indicates a failure to exclude the AAA from the circulation. We describe our experience with open surgery of post-EVAR sac expansion. A consecutive series of 68 EVAR patients was followed up. Endovascular and minimally invasive procedures were the initial treatment option. Failure of these attempts to curtail AAA sac expansion or type 2 large endoleaks (EL) resulted in opening of the aneurysm sac. The procedure includes positioning of a deflated occlusion balloon proximal to the stent graft (SG). Laparotomy with opening of the eneurysm sac was then performed. The thrombus was removed and backbleeding vessels oversewn. The aneurysm sac was then plicated over the SG. Four patients (5.9%) were diagnosed as having either persistent large type 2 EL or sac enlargement. In all patients the procedure was accomplished successfully. One patient died from acute myocardial infarction perioperatively. Three patients recovered uneventfully and follow-up computed tomography confirmed the absence of endoleak and a disappearance of the AAA. We believe that whenever EVAR fails to exclude the aneurysm from the circulation, open exploration without graft replacement should be considered.

Late open conversion after endovascular abdominal aortic aneurysm repair

OBJECTIVE

This study determined the incidence, the surgical details, and the outcome of late open conversion after failed endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm.

METHODS

A review of English-language medical literature from 1991 to 2014 was conducted using the PubMed and EMBASE databases to find all studies involving late conversion after EVAR for abdominal aortic aneurysm. The search identified 26 articles encompassing 641 patients (84% men; median age, 73.5 years).

RESULTS

Mean interval from the initial implantation was 38.5 ± 10.7 months. The cumulative single-center open conversion rate was 3.7%. The indications for late open conversion included endoleak in 62.4%, infection in 9.5%, migration in 5.5%, and thrombosis in 6.7%. Operations were urgent in 22.5% of the patients. The 30-day mortality was 9.1%. Mortality rates were different between elective (3.2%) and nonelective patients (29.2%). Five aneurysm-related deaths (1.5%) and two graft infections (0.6%) occurred during a median follow-up of 26.4 months (range, 5-50.2 months).

CONCLUSIONS

The number of patients with failed EVAR and without further options for endovascular salvage is growing. Endoleak remains the most important weakness of EVAR as the leading cause of late open conversion. Such procedures, although technically demanding, are associated with relatively low mortality rates when performed electively. Open repair still represents a valuable solution for many patients with failed EVAR.

Endovascular stent-graft excision and surgical aortic reconstruction

Endovascular aneurysm repair is being used more often and replacing open surgical repair as the treatment option for aortic aneurysm. Early results are better than those of open surgical repair, but the need for a second intervention is greater. Excision of a previously placed stent-graft by different surgical methods is very difficult and has high mortality and morbidity rates. We describe 3 patients who had previous endovascular aneurysm repair and were treated by an open surgical method with near total excision, leaving part of the stent-graft in the native aortic tissue.

Abdominal Aortic Aneurysm neck morphology: Proposed classification system

BACKGROUND

While aneurysm neck length, angulation and width have all been previously assessed in endovascular abdominal aortic aneurysm repair (EVAR), aneurysm neck shape has not been considered.

AIMS

To analyse the influence of aneurysm neck morphology on outcome following EVAR.

METHODS

Aneurysm neck morphology in 70 patients undergoing EVAR from April 2001 to May 2004 was determined using pre-operative CT scans and graft plans. Necks were classified as flared, parallel, irregular, conical, barrel or hourglass. End-points were death,Type I endoleak and graft migration.

RESULTS

Forty-six per cent of necks were flared, 34% parallel, 9% irregular, 6% conical, 3% barrel and 3% hourglass. Mean follow-up was 20.2 months (range 4-35). There was one Type I endoleak and one graft migration. There were no aneurysm related deaths.

CONCLUSIONS

Assessment of aneurysm neck morphology should be part of the routine preoperative workup for EVAR. A classification system of AAA necks is suggested to facilitate this.

Ten-year results of endovascular abdominal aortic aneurysm repair from a large multicenter registry

OBJECTIVE

To assess outcomes after endovascular abdominal aortic aneurysm repair (EVAR) in an integrated health care system.

METHODS

Between 2000 and 2010, 1736 patients underwent EVAR at 17 centers. Demographic data, comorbidities, and outcomes of interest were collected. EVAR in patients presenting with ruptured or symptomatic aneurysms was categorized as urgent; otherwise, it was considered elective. Primary outcomes were mortality and aneurysm-related mortality (ARM). Secondary outcomes were change in aneurysm sac size, endoleak status, major adverse events, and reintervention.

RESULTS

Overall, the median age was 76 years (interquartile range, 70-81 years), 86% were male, and 82% were Caucasian. Most cases (93.8%) were elective, but urgent use of EVAR increased from 4% in the first 5 years to 7.3% in the last 5 years of the study period. Mean aneurysm size was 5.8 cm. Patients were followed for an average of 3 years (range, 1-11 years); 8% were lost to follow-up. Intraoperatively, 4.5% of patients required adjunctive maneuvers for endoleak, fixation, or flow-limiting issues. The 30-day mortality rate was 1.2%, and the perioperative morbidity rate was 6.6%. Intraoperative type I and II endoleaks were uncommon (2.3% and 9.3%, respectively). Life-table analysis at 5 years demonstrated excellent overall survival (66%) and freedom from ARM (97%). Postoperative endoleak was seen in 30% of patients and was associated with an increase in sac size over time. Finally, the total reintervention rate was 15%, including 91 instances (5%) of revisional EVAR. The overall major adverse event rate was 7.9% and decreased significantly from 12.3% in the first 5 years to 5.6% in the second 5 years of the study period (P < .001). Overall ARM was worse in patients with postoperative endoleak (4.1% vs 1.8%; P < .01) or in those who underwent reintervention (7.6% vs 1.6%; P < .001).

CONCLUSIONS

Results from a contemporary EVAR registry in an integrated health care system demonstrate favorable perioperative outcomes and excellent clinical efficacy. However, postoperative endoleak and the need for reintervention continue to be challenging problems for patients after EVAR.

Conversion to open repair after endografting for abdominal aortic aneurysm: a review of causes, incidence, results, and surgical techniques of reconstruction

PURPOSE

To review the incidence, causes, and mortality rates of early and late conversion to open surgery after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm (AAA).

METHODS

A systematic search of the English-language literature from 2002 to 2009 was performed by interrogation of the PubMed, MEDLINE, and EMBASE databases. Studies were included if they: (1) had >100 patients treated with EVAR and (2) provided adequate data to calculate incidence and associated mortality rates. The search yielded 13 articles with sufficient data to analyze early conversion (12,236 patients, 178 conversions) and 15 articles with available data for late conversion (14,298 patients, 279 conversions).

RESULTS

The rate of early conversion among the 13 articles reviewed ranged from 0.8% to 5.9%; more recent studies carried lower rates of early conversion. Mortality rates of early conversion varied between 0% and 28.5%. Overall, there were 178 (1.5%) early conversions among the 12,236 AAAs treated with EVAR, with an average mortality of 12.4%. The rates of late conversion ranged from 0.4% to 22%. Of the 14,289 AAA patients undergoing endovascular repair, 279 (1.9%) required late conversion; the mortality rate was 10%.

CONCLUSION

Though the incidence is gradually declining, secondary interventions persist as the Achilles' heel of EVAR. A lifelong follow-up strategy for AAA patients treated with EVAR is essential for early detection and treatment of complications of the procedure. Vascular surgeons should be familiar with the complex open conversion procedures.

Risk of reintervention after endovascular aortic aneurysm repair

BACKGROUND

The role of symptomatic presentation in directing reintervention after endovascular aortic aneurysm repair (EVAR) was investigated.

METHODS

All patients undergoing infrarenal EVAR between 2001 and 2009 were studied. Those needing reintervention were divided into symptomatic and asymptomatic presentations. Kaplan-Meier survival curves were used to calculate freedom from reintervention, and log rank tests for subgroup analyses. Multivariable analysis identified risk factors for reintervention.

RESULTS

The study included 553 patients with a mean(s.d.) age of 75(7) years and aneurysm diameter of 65(13) mm. The 30-day mortality rate was 2.5 per cent. Median follow-up was 31 (range 1-97) months. There were 86 reinterventions in 69 (12.5 per cent) of 553 patients; 41 presented with symptoms and 28 were asymptomatic. Reintervention-free survival rates at 1, 3 and 5 years were 90.1, 85.3 and 81.2 per cent. The reintervention rate was higher in patients who needed an intraoperative adjunct during the index procedure (P = 0.014) and in those who did not have intraoperative computed tomography angiography (P = 0.024). Intraoperative adjuncts were an independent risk factor for future reintervention (hazard ratio 2.62, 95 per cent confidence interval 1.18 to 3.76; P = 0.012).

CONCLUSION

Most patients requiring reintervention presented symptomatically. A high-risk subgroup may be identifiable to rationalize a postoperative surveillance programme.

Secondary Endovascular and Conversion Procedures for Failed Endovascular Abdominal Aortic Aneurysm Repair: Can We Still Be Optimistic?

The purpose of this study was to evaluate the incidence, etiology, and outcome of secondary endovascular and “open” conversion procedures after failed endovascular abdominal aortic aneurysm repair (EVAR). From January 1997 until December 2005, 625 patients with an infrarenal abdominal aortic aneurysm were treated by elective EVAR, with 98.7% ( n = 617) primary EVAR success. The mean follow-up of the 617 patients was 46.7 ± 11.2 months. One hundred of these patients (16.2%) required secondary endovascular or peripheral procedures, and 39 (6.3%) patients underwent a secondary abdominal conversion. There were 5 acute conversions (0.8%) and 34 elective conversions (5.5%). The pre-EVAR anatomic suitability data, the main cause of the secondary procedure, and stent graft type were compared between patients with primary EVAR success, patients in need of a secondary endovascular or peripheral procedure, and patients with abdominal conversion. The overall main causes for reinterventions were proximal migration ( n = 60; 9.7%), progressive kinking of the stent graft ( n = 59; 9.6%), and late type III endoleak ( n = 12; 1.9%). Multivariate logistic regression analysis showed that factors significantly correlated with secondary procedures were the abdominal aortic aneurysm's maximum diameter, the proximal neck's width and length, and particularly the commercial withdrawal of the stent graft ( p < .001). The morbidity and mortality rates of secondary endovascular or peripheral interventions were 0%. The mortality rate of acute secondary conversions was 20% ( n = 1) and of elective secondary conversions was 8.8% ( n = 3). The morbidity rates for acute and elective conversions were 0% and 65%, respectively. The aneurysm-related mortality rate in our series was below 1%. Abdominal conversion surgery still carries a high mortality rate, but the overall EVAR-related mortality rate remains low. Early pitfall detection and proper reintervention are crucial to long-term EVAR success.

A review of the in vivo and in vitro biomechanical behavior and performance of postoperative abdominal aortic aneurysms and implanted stent-grafts

Endovascular repair of abdominal aortic aneurysms has generated widespread interest since the procedure was first introduced two decades ago. It is frequently performed in patients who suffer from substantial comorbidities that may render them unsuitable for traditional open surgical repair. Although this minimally invasive technique substantially reduces operative risk, recovery time, and anesthesia usage in these patients, the endovascular method has been prone to a number of failure mechanisms not encountered with the open surgical method. Based on long-term results of second- and third-generation devices that are currently becoming available, this study sought to identify the most serious failure mechanisms, which may have a starting point in the morphological changes in the aneurysm and stent-graft. To investigate the "behavior" of the aneurysm after stent-graft repair, i.e., how its length, angulation, and diameter change, we utilized state-of-the-art ex vivo methods, which researchers worldwide are now using to recreate these failure modes.

The Durability of Evar — What are the Evidence and Implications on Follow-Up?

Background and Aims:

To investigate the durability of EVAR and to explore the evidence for follow-up investigations. Furthermore, to study the patients' impressions of follow-up investigations, and how complications and secondary procedures influence cost-effectiveness.

Material and Methods:

263 patients were treated by EVAR from february 1995-february 2007. The series is divided into two groups with the year 2000 as a cut-off point since a new generation of stent grafts was then introduced. Early and late complications and secondary procedures were recorded. A questionnaire study was performed to investigate the patients' views on the follow-up program.

Results:

There was a significant reduction of complications from period I to period II, which was also reflected in the reduction of secondary procedures. Freedom from secondary procedures were 47% and 93% at 5 years follow-up in the two periods, respectively. In phase II, 7.5% of the patients needed a secondary procedure. Limb extension and femoro-femoral bypass were the most common procedures. Since late complications still occur, and can be unpredictable, a follow-up program is necessary. The vast majority of the patients tolerated the follow-up program well.

Conclusions:

Although the number of complications following EVAR has decreased significantly over the years, a thorough follow-up program is still necessary. This follow-up regime is well tolerated by the patients. Reduction of secondary procedures is important to improve the cost-effectiveness of EVAR.

Late aneurysm rupture after repressurization of a thrombosed stent-graft

PURPOSE

To report late abdominal aortic aneurysm (AAA) rupture after endovascular stent-graft repair despite complete thrombotic stent-graft occlusion.

CASE REPORT

A 65-year-old man underwent successful endovascular aneurysm repair (EVAR) with a Stentor device in 1995. In the interim course, the patient developed complete thrombotic stent-graft occlusion, which was treated with an axillobifemoral bypass. After 8 years, the patient presented with a reperfused and ruptured infrarenal AAA. Open repair was performed, with a good clinical result and exclusion of the AAA.

CONCLUSION

Thrombosed stent-grafts and aneurysms can transmit systemic arterial pressure and cause late rupture. Lifelong surveillance is mandatory in EVAR patients.

Lost to follow-up: a potential under-appreciated limitation of endovascular aneurysm repair

OBJECTIVE

It has long been evident that lifetime follow-up after endovascular aneurysm repair (EVAR) is necessary to identify late complications. The purpose of this study is to test the hypothesis that late follow-up rates for EVAR in routine practice are inferior to those reported from protocol-driven clinical trials, consequently contributing to avoidable events associated with poor long-term outcome.

METHODS

From February 1999 to December 2005, 302 EVARs were performed and eligible for follow-up. Of these, 47 were performed as part of an industry-sponsored clinical trial (study patients). Responsibility for follow-up was assigned to a research nurse for study patients and to office clerical staff for nonstudy patients. Follow-up compliance was classified as either frequent (<1 missed scheduled appointment) or incomplete (>2 missed scheduled appointments). Overall survival and complication rates were analyzed.

RESULTS

Of the 302 patients, 203 (67.2%) had frequent follow-up and 99 (32.8%) had incomplete follow-up. The mean follow-up was significantly better in the frequent follow-up group (34.7 +/- 22 months) vs the incomplete follow-up group (18.8 +/- 18.6 months, P < .001). The 5-year survival (63.9% frequent vs 64.0% incomplete), the 5-year reintervention rate (22.3% frequent vs 10.8% incomplete), and incidence of known endoleak (14.8% frequent vs 9.1% incomplete) were statistically similar in the two groups. The incidence of major adverse events, defined as events requiring urgent surgical intervention, was significantly increased in the incomplete follow-up group (6.1% vs 0.5%; P = .006), with nearly half of these patients dying perioperatively. There was no difference in measured outcomes for study patients compared with nonstudy patients. However, mean follow-up was significantly longer for study patients vs nonstudy patients (44.8 +/- 23.7 months vs 26.8 +/- 20.9 months; P < .001).

CONCLUSIONS

Follow-up surveillance after EVAR is less intense in practice environments outside of clinical trials. Patients with incomplete follow-up have higher fatal complication rates than patients with frequent follow-up. These data expose a potential under-appreciated limitation of EVAR, questioning whether the findings in clinical trials defining the efficacy of EVAR can be routinely extrapolated to ordinary practice.

Endovascular abdominal aortic aneurysm repair

The operative mortality following conventional abdominal aortic aneurysm (AAA) repair has not fallen significantly over the past two decades. Since its inception in 1991, endovascular aneurysm repair (EVAR) has provided an alternative to open AAA repair and perhaps an opportunity to improve operative mortality. Two recent large randomised trials have demonstrated the short and medium term benefit of EVAR over open AAA repair, although data on the long term efficacy of the technique are still lacking. This review aimed at providing an overview of EVAR and a discussion of the potential benefits and current limitations of the technique.

Long-term outcome and reintervention after endovascular abdominal aortic aneurysm repair using the Zenith stent graft

OBJECTIVE

To assess the long-term performance of the bifurcated Zenith stent graft.

METHODS

A total of 325 patients (300 men and 25 women) underwent elective endovascular abdominal aortic aneurysm repair with bifurcated Zenith stent grafts between October 1998 and December 2005. Follow-up included routine contrast-enhanced computed tomography and multiview abdominal radiographs at 1, 6, and 12 months and yearly thereafter. Data on late-occurring (>30 days after stent-graft implantation) complications and interventions were collected prospectively.

RESULTS

Of the original 325 patients, 92 have since died, resulting in a mean follow-up of 2.3 years (range, 1 month to 7.0 years). Nine (2.8%) of 325 patients required reintervention to treat or prevent endoleak (type I or III) or graft occlusion at an average of 1.4 years after stent-graft placement (range, 40 days to 4.0 years). Three (0.9%) of these patients died from causes related to malfunction of the stent graft: one each from aneurysm rupture, stent-graft infection, and infection of a femoral-femoral bypass graft placed after limb occlusion. Nineteen additional patients (5.8%) required treatment for type II endoleak, for a total reintervention rate of 8.6%.

CONCLUSIONS

Late failures of Zenith stent-graft attachment, structure, or function are rare. In the absence of known endoleak, routine follow-up imaging plays a limited role in the identification and prevention of impending failure.

Should usual criteria for intervention in abdominal aortic aneurysms be "downsized," considering reported risk reduction with endovascular repair?

Two randomized trials have demonstrated the safety of waiting until abdominal aortic aneurysm (AAA) diameter reaches 5.5 cm for repair in most patients. Other recent randomized trials have demonstrated lower perioperative mortality and morbidity with endovascular aneurysm repair (EVAR) compared to open surgery. Therefore, it is logical to assume that endovascular repair may change the appropriate threshold for intervention. However, endovascular repair is not as durable as open surgery and is associated with ongoing risks of rupture and reintervention. Decision analysis based on data available in 1998 showed that endovascular repair should not change the threshold for intervention. Since that time retrospective data have emerged to suggest that outcomes with endovascular repair are improved in smaller AAAs, although this may simply represent selection bias and the natural history of small AAAs. Randomized trials are appropriate to determine whether improved endovascular outcomes in small AAAs reduce late rupture and reintervention enough to justify early intervention in patients with appropriate anatomy. In the absence of data from these trials, the threshold for intervention should not be changed.

Accurate Detection of Stent-Graft Migration in a Pulsatile Aortic Model Using Roentgen Stereophotogrammetric Analysis

PURPOSE

To evaluate the feasibility and accuracy of Roentgen stereophotogrammetric analysis (RSA) versus computed tomography (CT) for detecting stent-graft migration in an in vitro pulsatile circulation model and to study the feasibility of a nitinol endovascular clip (NEC) as an aortic wall reference marker for RSA.

METHODS

An aortic model with stent-graft was constructed and connected to an artificial circulation with a physiological flow and pressure profile. Tantalum markers and NECs were used as aortic reference markers for RSA analysis. Stent-graft migrations were measured during pulsatile circulation with RSA and CT. CT images acquired with 64 x 0.5-mm beam collimation were analyzed with Vitrea postprocessing software using a standard clinical protocol and central lumen line reconstruction. RSA in the model with the circulation switched off was used as the reference standard to determine stent-graft migration. The measurement errors of RSA and CT were determined during pulsatile circulation.

RESULTS

The mean measurement error +/- standard deviation (maximum) of RSA during pulsatile circulation using the tantalum markers was -0.5+/-0.16 (0.7) mm. Using the NEC, the mean (maximum) measurement error was -0.4+/-0.25 (1.1) mm. The mean (maximum) measurement error of CT was -1.1+/-1.17 (2.8) mm.

CONCLUSION

RSA is an accurate and feasible tool to measure stent-graft migration in a pulsatile environment. Migration measurement with RSA was more accurate than CT in this experimental setup. The nitinol clip tested in this study is potentially feasible as an aortic reference marker in patients after endovascular repair.

Conversion to open surgery after endovascular abdominal aortic aneurysms repair

The authors describe experience with conversions to open surgery after endovascular abdominal aneurysm repair and evaluate the frequency, causes and results of a total of 7 cases in their series of 165 patients treated over a 10-year period.

Surgical corrections of endovascular aneurysms: repair complications

The authors describe their experience with the use of 21 open surgical corrections after endovascular abdominal aneurysm repair, reporting the frequency, type and outcome of these procedures in their group of 165 patients treated during a 10-year period.

Roentgen Stereophotogrammetric Analysis: An Accurate Tool to Assess Stent-Graft Migration

PURPOSE

To evaluate in an in vitro model the feasibility and accuracy of Roentgen stereophotogrammetric analysis (RSA) versus computed tomography (CT) for the ability to detect stent-graft migration.

METHODS

An aortic model was constructed from a 22-mm-diameter Plexiglas tube with 6-mm polytetrafluoroethylene inlays to mimic the renal arteries. Six tantalum markers were placed in the wall of the aortic tube proximal to the renal arteries. Another 6 markers were added to a Gianturco stent, which was cast in Plexiglas and placed inside the aorta and fixed to a micromanipulator to precisely control displacement of the stent along the longitudinal axis. Sixteen migrations were analyzed with RSA software and compared to the micromanipulator. Thirty-two migrations were measured by 3 observers from CT images acquired with 16x0.5-mm beam collimation and reconstructed with a 0.5-mm slice thickness and a 0.4-mm reconstruction interval. Measurements were made with Vitrea postprocessing software using a standard clinical protocol and central lumen line reconstruction. Results of CT were also compared to the micromanipulator.

RESULTS

The mean RSA measurement error compared to the micromanipulator was 0.002+/-0.044 mm, and the maximum error was 0.10 mm. There was no statistically significant interobserver variability for CT (p=0.17). The pooled mean (maximum) measurement error of CT was 0.14+/-0.29 (1.00) mm, which was significantly different from the RSA measurement error (p<0.0001).

CONCLUSION

Detection of endograft migration by RSA is feasible and was significantly more accurate than CT in this nonpulsatile in vitro model.