Talent LPS AAA stent graft: results of a pivotal clinical trial

Sex-specific criteria for repair should be utilized in patients undergoing aortic aneurysm repair

OBJECTIVE

Female patients are more likely to undergo repair of intact and ruptured abdominal aortic aneurysm (AAA) at smaller aortic diameter compared with male patients. By adjusting for inherent anatomic differences between sexes, aortic size index (ASI) and aortic height index (AHI) may provide an additional method for guiding treatment. We therefore analyzed sex-specific criteria for AAA repair using aortic diameter, ASI, and AHI.

METHODS

We identified all patients who underwent AAA repair between 2003 and 2019 in the Vascular Quality Initiative database. The Dubois and Dubois formula was used to calculate body surface area; aortic diameter was divided by body surface area to calculate ASI. Aortic diameter was divided by height to calculate AHI. Cumulative distribution curves were used to plot the proportion of patients who underwent repair of ruptured aneurysm according to aortic diameter, ASI, and AHI. Multivariable logistic regression modeling was used to identify the association of female sex with perioperative mortality and any major postoperative complication.

RESULTS

We identified 55,647 patients, of whom 12,664 were female (20%). For both intact and rupture repair, female patients were older, less likely to undergo endovascular aneurysm repair, and more likely to have comorbid conditions. Female patients underwent repair at smaller median aortic diameter compared with male patients for intact (5.4 vs 5.5 cm; P < .001) and rupture repair (6.7 vs 7.7 cm; P < .001). However, ASI was higher in female patients for both intact (3.1 vs 2.7 cm/m²; P < .001) and rupture repair (3.8 vs 3.7 cm/m²; P < .001), whereas AHI was higher in female patients for intact repair (3.3 vs 3.1 cm/m; P < .001) but lower for rupture repair (4.1 vs 4.3 cm/m; P < .001). When analyzing the cumulative distribution of rupture repair in male patients, 12% of rupture repairs were performed at an aortic diameter below 5.5 cm. To achieve the same proportion of rupture repair in female patients, the repair diameter was only 4.9 cm. However, when ASI and AHI were used, female and male patients both reached 12% of rupture repair at an ASI of 2.7 cm/m² and an AHI of 3.0 cm/m.

CONCLUSION

Our study provides data to strongly support the sex-specific 5.0-cm aortic diameter threshold suggested for repair in female patients by the Society for Vascular Surgery. The high percentage of patients undergoing rupture repair below 5.5 cm in male patients and 5.0 cm in female patients highlights the need to better identify patients at risk of rupture at smaller aortic diameters.

Epidemiology of abdominal aortic aneurysms

Abdominal aortic aneurysm (AAA) disease remains a major source of morbidity in developed countries and can progress to life-threatening rupture if left untreated, with exceedingly high mortality. The goal of AAA management is to identify and electively repair AAAs before rupture. AAA disease burden and outcomes have improved over time with declining tobacco use and advancements in care across patients' disease course. The introduction of endovascular AAA repair, in particular, has allowed for elective AAA repair in patients previously considered too high risk for open surgery and has contributed to lower rates of AAA rupture over time. However, these improved outcomes are not universally experienced, and disparities continue to exist in the detection, treatment, and outcomes of AAA by sex, race, and ethnicity. Mitigating these disparities requires enhanced, focused efforts at preventing disease, promoting health, and delivering appropriate care among an increasingly diverse patient population.

Endovascular Aortic Aneurysm Repair with the Zenith AAA Endovascular Graft: Does Gender Affect Procedural Success, Postoperative Morbidity, or Early Survival?

The purpose of this study was to analyze the effect of gender on deployment, early morbidity, and survival after endovascular aortic aneurysm repair (EVAR) using the Zenith Endovascular Graft. Data were obtained from the U.S. Multicenter Zenith Endograft trial and complemented with results from the Zenith female registry, including 40 women (10.9%) and 326 men (89.1%). Data analysis included preoperative medical risk factors, aneurysm morphology, deployment, and postoperative morbidity data, and 30-day and 1-year results. Preoperatively, women more often had experienced thromboembolic events (13% vs 4.3%; P = 0.04), but less angina pectoris (24% vs 49%; P = 0.002) or myocardial infarction (18% vs 38%; P = 0.01) compared with men. Women had more angulated aneurysm necks and narrower iliac arteries compared with men. Procedural success, cardiovascular, pulmonary, renal, bowel-related, neurologic, or other adverse events were comparable, as were 30-day and 1-year survival. Females experienced more wound dehiscences (5.0% vs 0.0%; P = 0.01) and open surgical conversions in the first year (5%) compared with men (0.31%) ( P = 0.03). With more challenging aneurysm morphologies, women were found to be at a higher risk for conversion in the first year after EVAR using the Zenith endograft. This however does not translate into inferior survival or higher overall morbidity compared with men.

Endovascular and open surgical treatment of complications after endovascular aortic aneurysm repair: A single-center experience

While endovascular aortic aneurysm repair (EVAR) has proven to be a safer alternative to open surgical repair for infrarenal abdominal aortic aneurysms (AAA) repair, the development of stent-graft complications mandates follow-up computed tomography imaging to minimize AAA-related mortality. In this single-institution report, adverse EVAR events identified in 150 consecutive patients are detailed. Early morbidity was low (<3%), with only 1 patient death on post-procedure day 2. After discharge (mean follow-up of 24 months), 2 patients died from cancer and one AAA-related mortality occurred after open conversion for stent-graft migration. Although computed tomography imaging detected no EVAR endoleak at 30 days, 19 patients developed an endoleak, including three Type I and four Type III leaks. Our institutional series review confirmed that EVAR of infrarenal AAA is a safe and valid alternative to open surgical repair, but sac embolization at the primary procedure in patients judged to be at high risk for Type II endoleak should be considered.

Management of Abdominal Aortic Aneurysm: A Decade of Progress

Since the world was first introduced to the concept of endovascular aneurysm repair by Parodi's landmark procedures in 1990, stent-grafts have assumed a prominent role in the management of abdominal aortic aneurysm. Most modern systems are trackable, accurate, and secure. The resulting endovascular procedure is safe, durable, effective, and versatile. Perhaps the most significant increment in the applicability of the endovascular technique was achieved by the development of bifurcated stent-grafts, which dispensed with inadequate distal aortic implantation sites. Additional branches and fenestrations now permit endovascular repair in cases of thoracoabdominal, pararenal, juxtarenal, and bilateral iliac aneurysms. These advances in device performance have been accompanied by a rapid dissemination of necessary skills, leading to the development of a new superspecialty of vascular therapy, with elements of vascular surgery, interventional radiology, and interventional cardiology.

Endograft Technology: Highlights of the past 10 Years

The past decade has seen the evolution of an exciting technology that has changed forever the treatment of aortic aneurysmal disease. From rather crude homemade stent-grafts constructed in the surgical suite to elegant commercially manufactured devices in a variety of configurations and sizes, the aortic endograft has experienced a meteoric rise in popularity to become a beneficial, minimally invasive therapy that can obviate the risk of rupture and death. There are now 3 approved endovascular devices on the market for infrarenal abdominal aortic aneurysm repair, and it is likely that additional and improved devices will become available in the future. This review revisits the developmental history of the aortic endograft, noting the ongoing refinements that have arisen from our experiences with the growing population of stent-graft patients. Although research continues to search for solutions to the problems of endoleak and migration, long-term results even with the earlier second and third-generation devices are better than has been achieved with open surgical repair.

Renal Function after Endovascular Aortic Aneurysm Repair: A Single-Center Experience with Transrenal versus Infrarenal Fixation

Purpose:

To describe the short-term consequences of endovascular aortic aneurysm repair (EVAR) on renal function after infrarenal (IR) versus transrenal (TR) stent-graft fixation.

Methods:

Between December 1996 and January 2006, 369 consecutive patients were treated with EVAR. All patients had an AneuRx or a Talent stent-graft implanted using IR (AneuRx) or transrenal (Talent) fixation. Post-EVAR, a standardized follow-up scheme included computed tomography (CT) scanning and serum creatinine measurements at 2 days, 3 months, and 12 months. Postoperative renal dysfunction was defined as a >20% decrease in serum creatinine clearance compared to baseline, the presence of new-onset dialysis, or both. Of the 369 patients, 309 (291 men; mean age 71±7 years, range 63–82) had complete 1-year follow-up and were included in this study. An IR stent-graft was placed in 190 patients, and a TR stent-graft was placed in the remaining 119 patients.

Results:

At discharge, renal dysfunction occurred in 3.7% of the patients in the IR group versus 5.9% in the TR group (p=NS) and rose significantly to 13.7% in the IR group (p=0.001) and 15.1% in the TR group (p=0.02) at the 1-year follow-up. However, no significant difference was noted between the IR and TR groups at either time point. At the 1-year follow-up, at least 50% of renal dysfunction was caused by obstructions of (accessory) renal arteries and renal infarctions. During the follow-up interval, 3 (0.97%) of 309 patients underwent new-onset dialysis.

Conclusion:

Both infrarenal and transrenal fixation techniques in EVAR will lead to a significant rise in renal dysfunction during the first year. A few patients with dysfunction will require dialysis.

Use of Proximal Aortic Cuffs as an Adjunctive Procedure during Endovascular Aortic Aneurysm Repair

The purpose of this study was to evaluate the incidence and durability of additional proximal cuffs during endovascular abdominal aortic aneurysm repair (EVAR). A retrospective review of 90 EVAR patients was conducted. Postoperative survival, proximal sealing zone–related complications, and secondary procedures were analyzed.

Additional proximal cuffs were used in 11%. Their use did not affect postoperative survival ( p = .58), type I endoleak rate (4.4%; p = .19), or the need for sealing zone–related secondary procedures (6.3%; p = .38) compared with patients without cuff placement but was related to a higher cumulative graft migration rate (2.2% overall p = .02). Two patients (2.5%; p = .79) underwent conversion to open surgery, both for proximal sealing zone–related complications.

Application of proximal cuffs appears to be an effective intraoperative adjunctive procedure to achieve a proximal seal during EVAR, with favorable midterm results. However, the risk of late endograft migrations may be elevated in this group.

Open versus Endovascular Repair of Abdominal Aortic Aneurysm in the Elective and Emergent Setting in a Pooled Population of 37,781 Patients: A Systematic Review and Meta-Analysis

Background. We evaluated the incidence of mortality and myocardial infarction (MI) in endovascular repair (EVAR) as compared to open aneurysm repair (OAR) in both elective and ruptured abdominal aortic aneurysm (AAA ) setting. Methods. We analyzed the rates of 30-day mortality, 30-day MI, and hospital length of stay (LOS) based on comparative observation and randomized control trials involving EVAR and OAR. Results. 41 trials compared EVAR to OAR with a total pooled population of 37,781 patients. Analysis of elective and ruptured AAA repair favored EVAR with respect to 30-day mortality with a pooled odds ratio of 0.19 (95% CI 0.17–0.20; I² = 88.9%; P < 0.001). There were a total of 1,835 30-day MI events reported in the EVAR group as compared to 2,483 events in the OAR group. The pooled odds ratio for elective AAA was 0.74 (95% CI 0.58–0.96; P = 0.02) in favor of EVAR. The average LOS was reduced by 296.75 hrs (95% CI 156.68–436.82 hrs; P < 0.001) in the EVAR population. Conclusions. EVAR has lower rates of 30-day mortality, 30-day MI, and LOS in both elective and ruptured AAA repair.

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.

Quality improvement guidelines for imaging detection and treatment of endoleaks following endovascular aneurysm repair (EVAR)

Major concerns after aortic aneurysm repair are caused by the presence of endoleaks, which are defined as persistent perigraft flow within the aortic aneurysm sac. Diagnosis of endoleaks can be performed with various imaging modalities, and indications for treatment are based on further subclassifications. Early detection and correct classification of endoleaks are crucial for planning patient management. The vast majority of endoleaks can be treated successfully by interventional means. Guidelines for Imaging Detection and Treatment of endoleaks are described in this article.

Systematic review and meta-analysis of sex differences in outcome after intervention for abdominal aortic aneurysm

Background

The aim of this study was to assess possible differences in mortality between men and women with an abdominal aortic aneurysm (AAA) treated either by elective repair or following aneurysm rupture.

Methods

A systematic literature search was performed using the MEDLINE, Cochrane and Embase databases. Data were analysed by means of bivariate random-effects meta-analysis. Data were pooled and odds ratios (ORs) calculated for women compared with men.

Results

Sixty-one studies (516 118 patients) met the predetermined inclusion criteria. Twenty-six reported on elective open AAA repair, 21 on elective endovascular repair, 25 on open repair for ruptured AAA and one study on endovascular repair for ruptured AAA. Mortality rates for women compared with men were 7·6 versus 5·1 per cent (OR 1·28, 95 per cent confidence interval (c.i.) 1·09 to 1·49) for elective open repair, 2·9 versus 1·5 per cent (OR 2·41, 95 per cent c.i. 1·14 to 5·15) for elective endovascular repair, and 61·8 versus 42·2 per cent (OR 1·16, 95 per cent c.i. 0·97 to 1·37) in the group that had open repair for rupture. The group that had endovascular repair for ruptured AAA was too small for meaningful analysis.

Conclusion

Women with an AAA had a higher mortality rate following elective open and endovascular repair.

Five-year results for the Talent enhanced Low Profile System abdominal stent graft pivotal trial including early and long-term safety and efficacy

OBJECTIVES

The pivotal trial of the Talent enhanced Low Profile System (eLPS; Medtronic Vascular, Santa Rosa, Calif) stent graft evaluated short and long-term safety and efficacy of endovascular aneurysm repair (EVAR). These data and a confirmatory group assessing the performance of the CoilTrac delivery system supported the United States premarket approval application for the device.

METHODS

The pivotal trial was a prospective, nonrandomized study conducted at 13 sites from February 2002 to April 2003. The study group (n = 166) underwent EVAR using the Talent eLPS stent graft. The control group (n = 243) underwent open surgical AAA repair. Data for this group were obtained from the Society for Vascular Surgery Endovascular AAA Surgical Controls project. Outcomes were compared at 30 days and 12 months. Additional 5-year follow-up was obtained for the eLPS group. A single-center cohort of 137 patients was the confirmatory group for the assessment of the clinical performance of the CoilTrac delivery system, with analysis of outcomes <or=30 days from the procedure.

RESULTS

AAA anatomy with neck length as short as 3 mm and maximum neck diameter of 32 mm were included in the eLPS group. EVAR was superior to open repair for periprocedural outcomes, including mean procedure duration (167.3 vs 196.4 minutes, P < .001), blood transfusion (18.2% vs 56.8%, P < .001), median intensive care unit stay (19.3 vs 74.3 hours, P < .001), and mean hospital stay (3.6 vs 8.2 days, P < .001). Freedom from major adverse events was 89.2% for EVAR at 30 days vs 44.0% (P < .001) and 81.3% vs 42.4% at 1 year (P < .001). Freedom from all-cause mortality and aneurysm-related mortality (ARM) was 93.7% and 98.2% for EVAR vs 92.4% and 96.7% for the controls. Through 5 years for the EVAR group, rates of freedom from all-cause mortality, ARM, aneurysm rupture, and conversion to surgery were 69.8%, 96.5%, 98.2%, and 99.1%, respectively, with one conversion to surgery, 25 secondary reinterventions, and five site-reported instances of stent graft migration. The technical success rate for the CoilTrac confirmatory group was 100%, with no aneurysm rupture or conversion to open repair at 30 days. The 30-day all-cause mortality rate was 1.5% (2 of 137).

CONCLUSIONS

In a population with challenging anatomic characteristics, EVAR with the Talent eLPS and use of the CoilTrac delivery system compared favorably with open repair through 1 year. Sustained protection from ARM, with minimal reinterventions, was attained through 5 years.

AAA stent-grafts: past problems and future prospects

Endovascular aneurysm repair (EVAR) has quickly gained popularity for infrarenal abdominal aortic aneurysm repair during the last two decades. The improvement of available EVAR devices is critical for the advancement of patient care in vascular surgery. Problems are still associated with the grafts, many of which can necessitate the conversion of the patient to open repair, or even result in rupture of the aneurysm. This review attempts to address these problems, by highlighting why they occur and what the failings of the currently available stent grafts are, respectively. In addition, the review gives critical appraisal as to the novel methods required for dealing with these problems and identifies the new generation of stent grafts that are being or need to be designed and constructed in order to overcome the issues that are associated with the existing first- and second-generation devices.

Effects of study design and trends for EVAR versus OSR

Purpose:

To investigate if study design factors such as randomization, multi-center versus single center evidence, institutional surgical volume, and patient selection affect the outcomes for endovascular repair (EVAR) versus open surgical repair (OSR). Finally, we investigate trends over time in EVAR versus OSR outcomes.

Methods:

Search strategies for comparative studies were performed individually for: OVID’s MEDLINE, EMBASE, CINAHL, HAPI, and Evidence Based Medicine (EBM) Reviews (including Cochrane DSR, ACP Journal Club, DARE and CCTR), limited to 1990 and November 2006.

Results:

Identified literature: 84 comparative studies pertaining to 57,645 patients. These include 4 randomized controlled trials (RCTs), plus 2 RCTs with long-term follow-up. The other 78 comparative studies were nonrandomized with 75 reporting perioperative outcomes, of which 16 were multi-center, and 59 single-center studies. Of the single-center studies 31 were low-volume and 28 were high-volume centers. In addition, 5 studies had all patients anatomically eligible for EVAR, and 8 studies included high-risk patients only. Finally, 25 long term observational studies reported outcomes up to 3 years.

Outcomes:

Lower perioperative mortality and rates of complications for EVAR versus OSR varied across study designs and patient populations. EVAR adverse outcomes have decreased in recent times.

Conclusion:

EVAR highlights the problem of performing meta-analysis when the experience evolves over time.

Cost and effectiveness comparison of endovascular aneurysm repair versus open surgical repair of abdominal aortic aneurysm: a single-center experience

The study objective was to compare the cost and effectiveness of two surgical techniques: open repair and endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm (AAA). We assessed 58 surgical operations of AAA repair conducted in 54 men and 4 women (aged 49-94 years) during 2003 and 2004. Open surgical repair was performed in 21 patients, and EVAR was performed in 37 patients. The evaluation of the effectiveness of both methods was based on the following factors: mortality within 30 days, surgery duration, total hospitalization time, and intensive care unit stay duration. The segmental costs of grafts, anesthesia, and extra materials were included in the calculations for the comparison of the costs of the two methods. A 30-day mortality of 5.17% and 0% was demonstrated for open surgical repair and EVAR, respectively. In regard to the operation's mean duration, this was calculated to 279.52 minutes for open repair and 193.57 minutes for EVAR. The mean duration of the in-hospital stay was 11.3 and 4.09 days for open repair and EVAR, respectively. Accordingly, the mean duration of intensive care unit stay was 2.81 and 0.23 days, respectively. The cost evaluation revealed a mean cost of 5374.3euro ($7,643.49) and 20,592.52euro ($29,287.50) for open repair and EVAR, respectively. Open repair is a "tested method" of its own time. EVAR seems to have the advantage on aspects of effectiveness, yet its major hallmark is its significant cost, as indicated in the relevant part of the current study.

A meta-analysis of 21 178 patients undergoing open or endovascular repair of abdominal aortic aneurysm

Background

Several studies have compared outcomes after elective open and endovascular approaches to abdominal aortic aneurysm (AAA) surgery, with varying results.

Methods

A random-effects meta-analysis was undertaken to compare operative outcomes, postoperative complications, 30-day mortality and long-term patient survival after surgery. Endpoints were compared using odds ratios (ORs), weighted mean differences (WMDs) or log hazard ratios (HRs) as appropriate.

Results

Forty-two studies comprising 21 178 patients (10 855 open; 10 323 endovascular) were included. In the elective setting (20 715 patients), the endovascular method was associated with a shorter stay in intensive care (WMD − 36 h; P &lt; 0·001) and a shorter total postoperative stay (WMD − 5·4 days; P &lt; 0·001). Cardiac (OR 1·76; P = 0·002) and respiratory (OR 4·01; P &lt; 0·001) complications were more common after open surgery. In the endovascular group, 30-day mortality was lower (OR 0·46; P &lt; 0·001). Endovascular surgery was also associated with an improved long-term aneurysm-related mortality (HR 0·39; P &lt; 0·001). For ruptured AAA (463 patients), the less invasive operation was associated with a reduced stay in intensive care (WMD − 100·4 h; P = 0·005) and a significantly lower 30-day mortality (OR 0·45; P = 0·005).

Conclusions

The endovascular repair of AAA offers a clear benefit in terms of reduction in postoperative adverse events and 30-day mortality. In the longer term, it is also associated with a reduction in aneurysm-related mortality, but not in all-cause mortality.

Systematic Review and Meta-analysis of 12 Years of Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

Endovascular repair (ER) of abdominal aortic aneurysm (AAA) is a new technique, and reported rates of endoleak, conversion to open repair, rupture and mortality vary widely. The aim of this study was to estimate these rates from the published data, and examine how this has changed as more patients have undergone ER.

METHODS

A systematic review and meta-analysis of publications identified through searches of the electronic databases EMBASE and Medline. All publications quoting endoleak, conversion to open repair, rupture and mortality rates for a series of patients undergoing ER were included.

RESULTS

163 studies pertaining to 28,862 patients undergoing ER were identified as relevant for the review and meta-analysis. The pooled estimate for operative mortality was 3.3% (95% confidence interval 2.9 to 3.6%). The pooled estimate for type 1 endoleaks was 10.5% (95% confidence interval 9.0 to 12.1%), with an annual rate of 8.4% (95% confidence interval 5.7% to 12.2%). The pooled estimate of type 2,3 and 4 endoleaks was 13.7% (95% confidence interval 12.3 to 15.3%), with an annual rate of 10.2% (95% confidence interval 7.4% to 14.1%). The pooled estimate for primary conversion to open repair was 3.8% (95% confidence interval 3.2 to 4.4%), and for secondary conversion to open repair 3.4% (95% confidence interval 2.8 to 4.2%). The pooled estimate for post-operative rupture was 1.3% (95% confidence interval 1.1 to 1.7%), with an annual rupture rate of 0.6% (95% confidence interval 0.5% to 0.8%). Multivariate meta-regression analysis showed that rates of operative mortality, post-operative rupture and total number of endoleaks all fell significantly (p<0.05) over time.

CONCLUSIONS

This study demonstrates a low mortality and a gradual reduction in vascular morbidity and mortality associated with endovascular repair since it was first introduced.

Sac Hygroma After Endovascular Abdominal Aortic Aneurysm Repair: Successful Treatment with Endograft Relining

Aneurysm sac expansion following endovascular abdominal aortic aneurysm repair (EVAR) is typically associated with endoleaks that can be readily diagnosed on computed tomographic angiography (CTA), ultrasound, or catheter-directed arteriography. Sac hygromas are a cause of sac expansion without apparent endoleak and are presumed to be a result of ultrafiltration of serum manifested by accumulation of fibrinous, gelatinous material within the aneurysm sac following EVAR. Although there are no reported associated ruptures, sac expansion is nevertheless disconcerting and intervention is presumably indicated. We report a case of an expanding aneurysm after EVAR secondary to sac hygroma that was successfully treated with relining of the existing, original endograft.

The Mid-term Effect of Bare Metal Suprarenal Fixation on Renal Function Following Endovascular Abdominal Aortic Aneurysm Repair

OBJECTIVE

The aim of this study was to assess the mid term effect of proximal bare metal fixation design on renal function in patients undergoing endovascular repair (EVR) of abdominal aortic aneurysm (AAA).

METHODS

Consecutive EVR patients for AAA from December 1995-2001 were included and grouped to either infrarenal (Group 1) or uncovered suprarenal (Group 2) fixation. Peri-operative renal function and at 6, 12 and 24 months was determined by serum creatinine (sCr mmol l(-1)) and Cockroft-Gault creatinine clearance (CrC ml min(-1)). Changes in renal function were compared using non-parametric analysis.

RESULTS

Of the 179 EVR procedures during this six-year period, paired renal data was available for 135 patients at a minimal follow-up of 6 months (Gp1, n = 63; Gp2, n = 72). Median pre-EVR sCr and CrC were 113, 57 in Group 1 and 108, 58 in Group 2, p = NS. There was no significant deterioration in renal function within or between either group at 2 years post-EVR: median sCr, CrC values were 118, 56 (Group 1) and 111, 56 (Group 2), all p = NS.

CONCLUSION

This study suggests mid-term renal function remains unaffected following EVR of AAA, irrespective of proximal fixation type. Designs to improve stent durability and EVR applicability do not appear to compromise renal function.

Long-term outcomes after endovascular abdominal aortic aneurysm repair: the first decade

OBJECTIVE

The proper role of endovascular abdominal aortic aneurysm repair (EVAR) remains controversial, largely due to uncertain late results. We reviewed a 12-year experience with EVAR to document late outcomes.

METHODS

During the interval January 7, 1994 through December 31, 2005, 873 patients underwent EVAR utilizing 10 different stent graft devices. Primary outcomes examined included operative mortality, aneurysm rupture, aneurysm-related mortality, open surgical conversion, and late survival rates. The incidence of endoleak, migration, aneurysm enlargement, and graft patency was also determined. Finally, the need for reintervention and success of such secondary procedures were evaluated. Kaplan-Meier and multivariate methodology were used for analysis.

RESULTS

Mean patient age was 75.7 years (range, 49-99 years); 81.4% were male. Mean follow-up was 27 months; 39.3% of patients had 2 or more major comorbidities, and 19.5% would be categorized as unfit for open repair. On an intent-to-treat basis, device deployment was successful in 99.3%. Thirty-day mortality was 1.8%. By Kaplan-Meier analysis, freedom from AAA rupture was 97.6% at 5 years and 94% at 9 years. Significant risk factors for late AAA rupture included female gender (odds ratio OR, 6.9; P = 0.004) and device-related endoleak (OR, 16.06; P = 0.009). Aneurysm-related death was avoided in 96.1% of patients, with the need for any reintervention (OR, 5.7 P = 0.006), family history of aneurysmal disease (OR, 9.5; P = 0.075), and renal insufficiency (OR, 7.1; P = 0.003) among its most important predictors. 87 (10%) patients required reintervention, with 92% of such procedures being catheter-based and a success rate of 84%. Significant predictors of reintervention included use of first-generation devices (OR, 1.2; P < 0.01) and late onset endoleak (OR, 64; P < 0.001). Current generation stent grafts correlated with significantly improved outcomes. Cumulative freedom from conversion to open repair was 93.3% at 5 through 9 years, with the need for prior reintervention (OR, 16.7; P = 0.001) its most important predictor. Cumulative survival was 52% at 5 years.

CONCLUSIONS

EVAR using contemporary devices is a safe, effective, and durable method to prevent AAA rupture and aneurysm-related death. Assuming suitable AAA anatomy, these data justify a broad application of EVAR across a wide spectrum of patients.

Stent-Grafts for Unruptured Abdominal Aortic Aneurysms: Current Status

Aortic stent-grafts were introduced at the beginning of the 1990s as a less invasive method of dealing with aortic aneurysms in patients with poor cardiovascular reserve. The numbers of procedures performed worldwide has increased exponentially despite the current lack of any substantial evidence for long-term efficacy in comparison with the gold standard of open surgical grafting. This review summarizes the evolution of the abdominal aortic stent-graft, the techniques used for assessment and deployment, and the effect of the procedure on both the patient and the device. The recent publication of two national multicenter trials has confirmed that the endovascular technique confers a 2.5-fold reduction in 30-day mortality in comparison with open surgery. However, over 4 years of follow-up, there is a 3-fold increase in the risk of reintervention and the overall costs are 30% greater with endovascular repair. Although the improvement in aneurysm-related mortality persists in the mid-term, because of the initial reduction in perioperative mortality, the all-cause mortality rate at 4 years is actually no better than for open surgery. Longer-term data from the randomized trials are awaited as well as results from the latest trials utilizing state-of-the-art devices. Whilst the overall management of abdominal aortic aneurysms has undoubtedly benefited from the introduction of stent-grafts, open repair currently remains the gold standard treatment.

Embolization-driven Occlusion of the Abdominal Aortic Aneurysmal Sac as the Basis of Prevention of Endoleaks in a New Swine Model

OBJECTIVES

To assess the effect of a new polymer in embolization of endoleaks using an animal model.

METHODS

A modified aortic stent-graft was placed in 20 pigs. Embolization was performed at the time of graft insertion with non-cytotoxic n-butyl-2-cyanoacrylate-metacryloxysulpholane and lipiodol (0.2:0.8ratio, 2 ml). Angiography, scanning electron microscopy and immuno-histochemistry were obtained at day 0, 1 week and 3 months.

RESULTS

In control animals both type I and II endoleaks were demonstrated. In treated animals, neither type-I nor type-II endoleaks were observed and a fibro-proliferative response was demonstrated within the aneurysm thrombus.

CONCLUSIONS

Host vascular responses govern the fate of the excluded aneurysm. Embolization of the sac and feeding arteries with non-cytotoxic glue sealed all occlusions by stimulating a massive restenosis-like process.

Aneurysm Diameter and Proximal Aortic Neck Diameter Influence Clinical Outcome of Endovascular Abdominal Aortic Repair: A 4-Year EUROSTAR Experience

Our objective was to evaluate the effect of preoperative aneurysm and aortic neck diameter on clinical outcome after infrarenal abdominal endovascular aneurysm repair (EVAR). Data of patients in the European Collaborators Registry on Stent-Graft Techniques for Abdominal Aortic Aneurysm Repair (EUROSTAR) registry base who underwent EVAR with Talent stent grafts were analyzed. Patient characteristics and clinical outcomes were compared among four groups defined by preoperative abdominal aortic aneurysm (AAA) and proximal aortic neck diameter: A, AAA < or =60 mm and neck < or =26 mm; B, AAA >60 mm and neck < or =26 mm; C, AAA < or =60 mm and neck >26 mm; and D, AAA >60 mm and neck >26 mm. Over a 7-year period, 1,317 patients underwent EVAR. Patients in groups B and D were significantly older and had a higher American Society of Anesthesiologists score compared with groups A and C (p=0.002 and 0.003, respectively). Mortality rate was highest in group D (p=0.002), as were rupture and conversion rates (p=0.015 and 0.037, respectively). This study demonstrates that patients with an AAA >60 mm and a proximal aortic neck >26 mm have worse clinical outcome after EVAR.

Pain and Quality of Life Assessment after Endovascular Versus Open Repair of Abdominal Aortic Aneurysms in Patients at Low Risk

PURPOSE

To compare functional autonomy, quality of life (QOL), and pain control after endovascular and open repair (OR) of abdominal aortic aneurysms.

MATERIALS AND METHODS

Forty patients with a low surgical risk profile and anatomic compatibility for stent-graft therapy were randomized to receive OR or endovascular aneurysm repair (EVAR). Technical and clinical success as well as mortality were assessed in both groups and compared by Kaplan-Meier analysis. Functional autonomy and QOL were assessed by Karnofsky score and Short Form 36 (SF-36) questionnaire. Pain control was assessed by a numeric rating scale and Brief Pain Inventory questionnaire. QOL outcomes by means of the SF-36 and pain questionnaires were compared with use of mixed-effects models for repeated-measures analysis.

RESULTS

All procedures were technically successful in both groups. Three late clinical failures requiring surgical conversion or repeated intervention were observed in the EVAR group and one was observed in the OR group. There was no significant difference between groups in terms of functional autonomy or QOL. No difference in pain level was evident during the early postoperative period, whereas the pain level was lower in the OR group after 1 month. Opioid analgesic drug consumption was significantly greater in the OR group during the postoperative period. Mean hospitalization duration was shorter in the EVAR group than in the OR group (4.5 days +/- 2.4 vs 11.5 days +/- 8.1; P= .001).

CONCLUSION

EVAR has no advantage over OR in patients at low risk in terms of functional autonomy, QOL, and pain control. However, EVAR was associated with shorter hospitalization durations compared with OR.

Systematic review of recent evidence for the safety and efficacy of elective endovascular repair in the management of infrarenal abdominal aortic aneurysm

Background

Conventional management of abdominal aortic aneurysm (AAA) is by open repair and is associated with a mortality rate of 2–6 per cent. Endovascular aneurysm repair (EVAR) is an alternative technique first introduced in 1991. A systematic review was undertaken of the evidence for the safety and efficacy of elective EVAR in the management of asymptomatic infrarenal AAA.

Methods

Thirteen electronic bibliographical databases were searched, covering biomedical, health-related, science and social science literature. Outcomes were assessed with respect to efficacy (successful deployment, technical success, conversion rates and secondary intervention rates) and safety (30-day mortality rate, procedure morbidity rates and technical issues—endoleaks, graft thrombosis, stenosis and migration).

Results

Of 606 reports identified, 61 met the inclusion criteria (three randomized and 15 non-randomized controlled trials, and 43 uncontrolled studies). There were 29 059 participants in total; 19 804 underwent EVAR. Deployment was successful in 97·6 per cent of cases. Technical success (complete aneurysm exclusion) was 81·9 per cent at discharge and 88·8 per cent at 30 days. Secondary intervention to treat endoleak or maintain graft patency was required in 16·2 per cent of patients. Mean stay in the intensive care unit and mean hospital stay were significantly shorter following EVAR. The 30-day mortality rate for EVAR was 1·6 per cent (randomized controlled trials) and 2·0 per cent in nonrandomized trials and case series. Technical complications comprised stent migration (4·0 per cent), graft limb thrombosis (3·9 per cent), endoleak (type I, 6·8 per cent; type II, 10·3 per cent; type III, 4·2 per cent) and access artery injury (4·8 per cent).

Discussion

EVAR is technically effective and safe, with lower short-term morbidity and mortality rates than open surgery. However, there is a need for extended follow-up as the long-term success of EVAR in preventing aneurysm-related deaths is not yet known.

Lifeline registry of endovascular aneurysm repair: Long-term primary outcome measures

PURPOSE

To determine the long-term outcome after endovascular aneurysm repair (EVAR) of infrarenal abdominal aortic aneurysms (AAA).

METHODS

Review the primary outcome measures of patients treated with endovascular grafts (EG) in the Lifeline Registry of EVAR. The registry contains data on 2,664 EG patients and 334 open surgical control (SC) patients collected under four multicenter Investigational Device Exemption (IDE) clinical trials that lead to United States Food and Drug Administration (FDA) approval with mandatory 5-year follow-up. Primary outcome measures include operative mortality, AAA-related death, all-cause mortality, aneurysm rupture, and surgical conversion.

RESULTS

Pooled data from IDE clinical trials revealed that EG patients were 3 years older (73 +/- 8 years) than SC patients (70 +/- 8 years, P < .01) and had significantly more cardiac comorbidities before treatment. However, there was no difference in 30-day operative mortality between EG (1.7%) and SC (1.4%) (P = .72). Both EG and SC were successful in preventing rupture, with freedom from aneurysm rupture in 99.8% of EG and 100% of SC patients at 1 year (P = .51). Freedom from rupture remained at 99% in years 1 to 6 after EG, with no increasing risk of late rupture. There was no significant difference in the AAA-related death rate at 1 year between EG (98.2%) and SC (98.6%) (P = .64). Freedom from AAA-related death remained at 98% in years 1 to 6 after EG, with no increasing risk of late AAA-related death. Kaplan-Meier analysis at 6 years revealed freedom from aneurysm rupture in 99%, freedom from AAA-related death in 98%, and freedom from surgical conversion in 95% of EG patients. There was no difference in survival at 4 years between EG (74%) and SC (71%) (P = .49). Overall EG patient survival at 5 years was 66% and at 6 years was 52%. Women had a higher risk of rupture (2.4%) than men (1.2%) (P = .01) and a higher rate of surgical conversion (8.3%) than men (3.8%) (P < .01) but had the same low AAA-related death rate (3.5%) as men (2.1%) (P = .16) at 5 years. Most secondary interventional procedures (85%) were performed < or =30 days after EVAR. Freedom from secondary intervention was 84% at 1 year and 78% at 5 years.

CONCLUSIONS

Endovascular aneurysm repair using FDA-approved devices is a safe, effective, and durable treatment for anatomically suited patients with infrarenal abdominal aortic aneurysms.

Influence of Diabetes Mellitus on the Endovascular Treatment of Abdominal Aortic Aneurysms

PURPOSE

To investigate the influence of diabetes mellitus on outcome after endovascular abdominal aortic aneurysm (AAA) repair.

METHODS

Of 6017 patients enrolled in the EUROSTAR registry after undergoing endovascular AAA repair between May 1994 and December 2003, 731 (12%) had diabetes mellitus (690 men; mean age 72 years, range 37-100). Patient demographics, risk factors, aneurysm morphology, operative and procedural details, complications, major events, and regular follow-up information were compared. The relationships of complications and events to diabetes mellitus, which were tested with multivariate logistic regression analysis and Cox proportional hazards modeling, are expressed as odds ratios (OR) and hazard rates (HR) with 95% confidence intervals (CI). Survival was compared with life-table analysis.

RESULTS

A significantly higher risk of device-related complications was observed in diabetic patients (8% versus 6%, p < 0.049; OR 1.35, 95% CI 1.00 to 1.82). The greatest difference in the groups was in mortality, which was significantly higher in the diabetic population (13%) compared to the nondiabetic patients (10%, p < 0.039; OR 1.27, 95% CI 1.01 to 1.59). Deaths, which occurred at a higher frequency within the 30-day perioperative period in diabetic patients, were primary due to cardiac complications. Insulin-controlled type 2 diabetic patients had significantly lower rates of early and late endoleaks and secondary interventions than diet-controlled type 2 diabetics (p = 0.002, p = 0.0001, and p = 0.0008, respectively) and nondiabetic patients (p = 0.002, p = 0.0005, and p = 0.0025, respectively). The cumulative survival after 48 months did not differ significantly: 74% in diabetics and 79% in the population without diabetes.

CONCLUSIONS

Patients with diabetes mellitus had a significantly higher early mortality rate after EVAR, but their long-term survival was similar to nondiabetic patients.

Endograft technology: highlights of the past 10 years

The past decade has seen the evolution of an exciting technology that has changed forever the treatment of aortic aneurysmal disease. From rather crude homemade stent-grafts constructed in the surgical suite to elegant commercially manufactured devices in a variety of configurations and sizes, the aortic endograft has experienced a meteoric rise in popularity to become a beneficial, minimally invasive therapy that can obviate the risk of rupture and death. There are now 3 approved endovascular devices on the market for infrarenal abdominal aortic aneurysm repair, and it is likely that additional and improved devices will become available in the future. This review revisits the developmental history of the aortic endograft, noting the ongoing refinements that have arisen from our experiences with the growing population of stent-graft patients. Although research continues to search for solutions to the problems of endoleak and migration, long-term results even with the earlier second and third-generation devices are better than has been achieved with open surgical repair.

Suprarenal Endograft Fixation Avoids Adverse Outcomes Associated with Aortic Neck Angulation

The advent of endovascular therapy has had a profound impact on repair of abdominal aortic aneurysms (AAA). Prudent patient selection, particularly in regard to unfavorable anatomy, is emerging as perhaps the most important determinant of endovascular abdominal aortic aneurysm repair (EVAR) outcome. The aim of this study was to examine the association of one such anatomic factor, proximal aortic neck angulation, with the incidence of adverse events following EVAR. Prospectively collected data on 289 EVAR repairs with the Talent endograft (Medtronic, Inc., Minneapolis, MN) from March 1998 to June 2000 were analyzed. Stent graft-specific adverse events studied were migration, endoleak, kinking, thrombosis, and AAA expansion. Computed tomography (CT) scanning with three-dimensional post-processing and/or aortography was used to measure aortic neck angle. Patients were categorized into one of four groups according to their neck angle: I (0-10 degrees); II (11-39 degrees); III (40-59 degrees); or IV (60-85 degrees). Outcomes were evaluated by chi-squared analysis and ANOVA. There was a direct correlation between AAA diameter and neck angle (p = 0.002). There was no difference in endoleak rate (p = 0.877), stent migration (p = 0.850), or AAA expansion rate (p = 0.599) between groups. Device kinking >45 degrees was associated with neck angulation > or = 60 degrees (p = 0.013), but not with other adverse outcomes. The average neck angle was 30 degrees in patients with endoleaks and 31 degrees in patients without endoleaks. Increasing aortic neck angulation was not associated with the selected adverse outcomes within 1 year following EVAR with the Talent stent graft using suprarenal fixation with the exception of graft kinking. This may be related to the graft design that permits suprarenal aortic fixatiou of the proximal stent graft, Whether severe degrees of angulation of 60 degrees or greater can be safely treated with suprarenal fixation requires further study.

Past, Present, and Future Endograft Devices

Since the original descriptions of endovascular grafts for treatment of aneurysms, a number of devices and approaches have been developed. The following is a discussion summarizing the number of devices which have been developed and used in patients, as well as chosen the directions of this technology. The diversity of approach from an engineering and materials point of view speaks of the fact that opportunity exists for continued development in the future.