Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomised controlled trial

Risk prediction for perioperative mortality of endovascular vs open repair of abdominal aortic aneurysms using the Medicare population

OBJECTIVES

The impact of risk factors upon perioperative mortality might differ for patients undergoing open vs endovascular repair (EVAR) of abdominal aortic aneurysms (AAA). In order to investigate this, we developed a differential predictive model of perioperative mortality after AAA repair.

METHODS

A total of 45,660 propensity score matched Medicare beneficiaries undergoing elective open or endovascular AAA repair from 2001 to 2004 were studied. Using half the dataset we developed a multiple logistic regression model for a matched cohort of open and EVAR patients and used this to derive an easily evaluable risk prediction score. The remainder of the dataset formed a validation cohort used to confirm results.

RESULTS

The derivation cohort included 11,415 open and 11,415 endovascular repairs. Perioperative mortality was 5.3% and 1.8%, respectively. Independent predictors of mortality (relative risk [RR], 95% confidence interval [CI]) were open repair (3.2, 2.7-3.8); age (71-75 years 1.2, 0.9-1.6; 76-80 years 1.9, 1.4-2.5; >80 years 3.1, 2.4-4.2); female gender (1.5, 1.3-1.8); dialysis (2.6, 1.5-4.6); chronic renal insufficiency (2.0, 1.6-2.6); congestive heart failure (1.7, 1.5-2.1); and vascular disease (1.3, 1.2-1.6). There were no differential predictors of mortality across the two procedures. A simple scoring system was developed from a logistic regression model fit to both endovascular and open patients (area under the receiver operator curve [ROC] curve of 72.6) from which low, medium, and high risk groups were developed. The absolute predicted mortality ranged from 0.7% for an EVAR patient </=70 years of age with no comorbidities to 38% for an open patient >80 with all the comorbidities considered. Although relative risk was similar among age groups, the absolute difference was greater for older patients (with higher baseline risk).

CONCLUSION

Mortality after AAA repair is predicted by comorbidities, gender, and age, and these predictors have similar effects for both methods of AAA repair. This simple scoring system can predict repair mortality for both treatment options and thus may help guide clinical decisions.

Concurrent colorectal malignancy and abdominal aortic aneurysm: a multicentre experience and review of the literature

OBJECTIVES

There is lack of consensus regarding concurrent vs. staged approaches, and the prioritisation of staged procedures in cases presenting with colorectal carcinoma (CRC) and abdominal aortic aneurysm (AAA) synchronously. We aim to present our experience, review the literature on this therapeutic dilemma and examine the role of endovascular aortic repair (EVAR).

DESIGN, MATERIALS AND METHODS

An observational study of the experience of two centres and a systematic review of the published literature.

RESULTS

Twenty-four patients were identified from the prospective databases of two tertiary referral centres between 2001 and 2006. Intervention for both malignancy and aneurysm was performed in 13 patients. In 10 patients, cancer resection was performed initially and was followed by open aneurysm repair (n=3) or EVAR (n=7). Two patients (AAA diameters: 7.0 and 8.0cm) underwent EVAR prior to colonic resection. One patient was selected for synchronous surgery. There were no interval AAA ruptures, graft infection or postoperative mortalities. Literature review identified 269 such cases; of these 101 were treated by combined surgery. In staged surgery, there were nine interval aneurysmal ruptures and one aortic graft infection.

CONCLUSIONS

In our experience, staged management can be undertaken, without interval aneurysmal rupture. EVAR has an evolving role in preventing delay in CRC management, in high-risk patients, and during combined intervention.

A comparison between standard and high density Resilient AneuRx in reducing aneurysm sac pressure in a chronic canine model

OBJECTIVES

Low intra-aneurysm sac pressure has been shown to correlate with sac shrinkage following endovascular aneurysm repair (EVAR) whereas high pressure results in sac enlargement. The Resilient AneuRx (RSA) has higher density Dacron compared with the standard AneuRx (STA) and was developed in an attempt to reduce type 4 and 5 endoleaks, thereby more effectively reducing sac pressure. The purpose of this study is to compare the ability of RSA and STA in reducing sac pressure in a chronic canine aneurysm model.

MATERIALS AND METHODS

Artificial polytetrafluoroethylene (PTFE) aneurysm (26 x 50 mm) with an Endosure wireless pressure sensor (CardioMEMS, Atlanta, Ga) attached to the inner surface was implanted in the abdominal aorta of 10 mongrel dogs. Two weeks after creation of the aneurysm, each animal underwent EVAR with either STA (n = 5) or RSA (n = 5). Following EVAR, intra-sac pressure was measured with the implanted wireless pressure sensor up to 3 months postoperatively when the animals were sacrificed.

RESULTS

EVAR was successful with no signs of an endoleak in all 10 dogs. Pressure sensing with the wireless sensor was also successful in each animal until the end of the study. Systolic intra-sac pressure remained at a high level in the STA group, whereas it gradually lowered over time in the RSA group. This difference reached statistical significance at 2 months and lasted to 3 months. No endoleak was detected in either group at the time of sacrifice. Gross analysis confirmed that all the aneurysm sacs were thrombosed without any flow inside the sac.

CONCLUSION

Despite absence of an endoleak, intra-sac pressure remained high in the STA group. RSA effectively reduced sac pressure over time. Graft porosity appears to be an important factor that may determine the outcome of EVAR. These findings may be useful in designing improved endograft.

The PIVOTAL study: a randomized comparison of endovascular repair versus surveillance in patients with smaller abdominal aortic aneurysms

The diameter of an abdominal aortic aneurysm (AAA) is the single most important factor in deciding whether to repair an aneurysm or to monitor it conservatively. Open surgical repair does not appear to be beneficial until the diameter of the aneurysm is >5.5 cm. Prospective clinical trials, however, confirmed a lower risk of operative mortality after endovascular aneurysm repair (EVAR) than after open surgical repair. Further, retrospective analyses of EVAR databases suggested that EVAR outcome is directly related to aneurysm size and is better for smaller aneurysms than for larger aneurysms. Noting similar results with open surgical management vs surveillance in patients with smaller AAA, lower morbidity rates with EVAR vs open repair, and the favorable results with EVAR in smaller aneurysms, a clinical trial testing the hypothesis that EVAR is beneficial in patients with small AAA appeared warranted. To answer this question, the 70-site Positive Impact of endoVascular Options for Treating Aneurysm earLy (PIVOTAL) was begun. PIVOTAL has an enrollment goal of up to 1025 patients with a 4- to 5-cm AAA, randomly assigning patients to EVAR or surveillance. The primary end points of PIVOTAL are aneurysm rupture and AAA-related death at up to 36 months after randomization. When complete, the results of PIVOTAL should provide objective evidence to guide the use of EVAR for small AAAs.

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.

Comparison of EVAR and open repair in patients with small abdominal aortic aneurysms: can we predict results of the PIVOTAL trial?

OBJECTIVE

Data from multicenter studies support observation of small abdominal aortic aneurysms (AAAs) over open repair (OR), but the role of endovascular repair (EVAR) is unclear pending outcome of the Positive Impact of EndoVascular Options for Treating Aneurysm earLy (PIVOTAL) trial. Our goal was to predict the outcome of the trial by comparing results of small AAA repair using EVAR vs OR at a tertiary institution.

METHODS

Using selection criteria of PIVOTAL trial, we reviewed clinical data of 194 consecutive patients, who underwent EVAR or OR for 4.0-5.0 cm AAAs between 1997 and 2004. All-cause and aneurysm-related deaths, complications, reinterventions, ruptures, and conversions were documented; factors affecting outcome were analyzed using chi(2) tests, Wilcoxon rank-sum tests, logistic regression Kaplan-Meier method with log-rank tests, and Cox proportional hazards regression. Median follow-up was 3.9 years (range, 1 month to 9 years).

RESULTS

A total of 194 patients, 162 males, 32 females (mean age: 71 years, range, 46-86) underwent 162 OR and 32 EVAR. EVAR patients were older (mean 74 +/- 6 vs 71 +/- 7, P = .002), had lower ejection fraction (mean 54 +/- 11 vs 61 +/- 13, P = .0002), and less likely to have ever smoked (69% vs 85%, P = .03) than OR patients. Thirty-day mortality was 1.3% (2/162) for OR and 0% for EVAR (0/33) (P = not significant [NS]). There were 49 systemic complications (7 EVAR, 42 OR, P = NS) and 10 local complications (3 EVAR, 7 OR, P = NS). During follow-up, there were no conversions and no ruptures. Freedom from reinterventions at 5 years was 83.1% +/- 6.9% for EVAR and 95.3% +/- 1.8% for OR (P = 0.02). There were 26 deaths (3 EVAR, 23 OR); but no procedure or aneurysm-related death was confirmed after 30 days (cause unknown in 16 deaths, 62%). Survival rates at 1-year were 96.6% +/- 3.4% for EVAR and 97.4% +/- 1.3% for OR; 5-year rates were 86.9% +/- 7.2% +/- EVAR and 86.9% +/- 3.3% for OR (P = 0.69). Multivariate analysis revealed age (hazard ratio = 1.1 per year, P = .0496) and AAA size (hazard ratio = 13.8 per 1 cm, P = .03) were associated with death but EVAR vs OR was not (P = .23).

CONCLUSION

For repair of small AAAs, results of EVAR vs OR are not different at 5 years at a tertiary institution. Multicenter studies confirmed OR were not superior to observation in these patients. We predict the PIVOTAL study will conclude EVAR is not superior to observation.

A comparative study of myocardial injury during conventional and endovascular aortic aneurysm repair: measurement of cardiac troponin T and plasma cytokine release

BACKGROUND

Major aortic surgery results in significant haemodynamic and oxidative stress to the myocardium. Cytokine release is a major factor in causing cardiac injury during aortic surgery. Endovascular aortic aneurysm repair (EVAR) has the potential to reduce the severity of the ischaemia reperfusion syndrome and its systemic consequences.

AIM

The aim of this study was to investigate the occurrence of myocardial injury during conventional and endovascular abdominal aortic aneurysm repair using measurement of the myocardial-specific protein, cardiac troponin T. Interleukin-6 was also measured in both groups and haemodynamic responses to surgery assessed.

METHODS

Nine consecutive patients undergoing conventional infra-renal aortic aneurysm surgery were compared with 13 patients who underwent EVAR. Patients were allocated on the basis of aneurysm morphology and suitability for endovascular repair.

RESULTS

Patients undergoing open repair had significantly more haemodynamic disturbance than those having endovascular repair (mean arterial pressure at 5 min following unclamping or balloon deflation: open (69.6 + 3.3 mmHg); endovascular (86 + 4.4 mmHg), P < 0.05 vs. pre-op). Troponin T levels at 48 h post-operatively were higher in patients who underwent open repair (open 0.164 + 0.1 ng/ml; endovascular 0.008 + 0.0005 ng/ml, P < 0.04). Significantly more patients in the open repair group had troponin T levels > 0.1 ng/l when compared with the endovascular group (P < 0.01, chi (2) test)

CONCLUSION

Endovascular aortic surgery produces significantly less myocardial injury than the open technique of aortic aneurysm repair.

Thoracic stent graft versus surgery for thoracic aneurysm

BACKGROUND

Thoracic aortic aneurysm (TAA) is an uncommon disease with an incidence of 10.4 per 100,000 inhabitants. It occurs mainly in older individuals and is evenly distributed among both sexes. There are no signs or symptoms indicative of the presence of the disease. Progressive but unpredictable enlargement of the dilated aorta is the natural course of the disease and can lead to rupture. Open chest surgical repair using prosthetic graft interposition has been a conventional treatment for TAAs. Despite improvements in surgical procedures perioperative complications remain significant. The alternative option of thoracic endovascular aneurysm repair (TEVAR) is considered a less invasive and potentially safer technique, with lower morbidity and mortality compared with conventional treatment. Evidence is needed to support the use of TEVAR for these patients, rather than open surgery.

OBJECTIVES

The aim of this review is to assess the efficacy of TEVAR versus conventional open surgery in patients with TAAs.

SEARCH STRATEGY

The Cochrane Peripheral Vascular Diseases Group searched their Trials Register (last searched 10 October 2008), the Cochrane Central Register of Controlled Trials database (CENTRAL) (last searched The Cochrane Library 2008, Issue 4).

SELECTION CRITERIA

Randomised controlled trials in which patients with TAAs were randomly assigned to TEVAR or open surgical repair.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified and evaluated potential trials for eligibility. Excluded studies were further checked by another author. We did not perform any statistical analyses as no randomised controlled trials were identified.

MAIN RESULTS

We did not find any published or unpublished randomised controlled trials comparing TEVAR with conventional open surgical repair for the treatment of thoracic aortic aneurysms.

AUTHORS' CONCLUSIONS

Though stent grafting of the thoracic aorta is technically feasible and non-randomised studies suggest reduction of early outcomes such as paraplegia, mortality and hospital stay, high quality randomised controlled trials assessing all clinically relevant outcomes including open-conversion, aneurysm exclusion, endoleaks, and late mortality are needed.

Ureteric obstruction of solitary kidney following endovascular repair of infrarenal abdominal aortic aneurysm: a case report

Endovascular treatment of abdominal aortic aneurysm is commonplace at present. It has got lower mortality and morbidity compared to open surgical repair. However, it requires long-term follow-up. The main complications are endoleaks, stent migrations, kinks, and rupture. Ureteric obstruction is uncommon but an important complication following endovascular treatment of abdominal aortic aneurysms. We present a case of ureteric obstruction in a solitary kidney following endovascular repair of abdominal aortic aneurysm and its successful management by ureteric stenting.

Decrease in total aneurysm-related deaths in the era of endovascular aneurysm repair

OBJECTIVE

With the expansion of elective abdominal aortic aneurysm (AAA) repair after the introduction of endovascular aneurysm repair (EVAR), there is a concern that even with a lower operative mortality there could be an increasing number of aneurysm-related deaths. To evaluate this, we looked at national trends in AAA repair volume as well as mortality rates after intact and ruptured AAA repair encompassing the introduction of EVAR.

METHODS

Patients with intact or ruptured AAA undergoing open repair or EVAR and all those with a diagnosis of ruptured AAA were identified within the 1993 to 2005 Nationwide Inpatient Sample database using International Classification of Diseases, 9th Revision, diagnosis and procedure codes. The number of repairs, number of rupture diagnoses without repair, number of deaths, and associated mortality rates were measured for each year of the database. Outcomes (mean annual volumes) were compared from the pre-EVAR era (1993 to 1998) with the post-EVAR era (2001 to 2005).

RESULTS

Since its introduction, EVAR increased steadily and accounted for 56% of repairs yet only 27% of the deaths for intact repairs in 2005. The mean annual number of intact repairs increased from 36,122 in the pre-EVAR era to 38,901 in the post-EVAR era, whereas the mean annual number of deaths related to intact AAA repair decreased from 1693 pre-EVAR to 1207 post-EVAR (P < .0001). Mortality for all intact AAA repair decreased from 4.0% to 3.1% (P < .0001) pre-EVAR and post-EVAR, but open repair mortality was unchanged (open repair, 4.7% to 4.5%, P = .31; EVAR, 1.3%). During the same time, the mean annual number of ruptured repairs decreased from 2804 to 1846, and deaths from ruptured AAA repairs decreased from 2804 to 1846 (P < .0001). Mortality for ruptured AAA repair decreased from 44.3% to 39.9% (P < .0001) pre-EVAR and post-EVAR (open repair, 44.3% to 39.9%, P < .001; EVAR, 32.4%). The overall mean annual number of ruptured AAA diagnoses (9979 to 7773, P < .0001) and overall mean annual deaths from a ruptured AAA decreased post-EVAR (5338 to 3901, P < .0001).

CONCLUSION

Since the introduction of EVAR, the annual number of deaths from intact and ruptured AAA has significantly decreased. This coincided with an increase in intact AAA repair after the introduction of EVAR and a decrease in ruptured AAA diagnosis and repair volume.

EVAR in Small Versus Large Aneurysms: Does Size Influence Outcome?

Objective: To determine whether there is a difference in outcome between endovascular repair of abdominal aortic aneurysm (EVAR) of small versus large aneurysms. Methods: A total of 192 patients from the Power-link trial were subdivided into small abdominal aortic aneurysms (AAA; ≤5 cm) and large AAA (>5 cm) groups. Demographics, perioperative morbidity, mortality, overall survival, and freedom from major adverse events, endoleak, aneurysm-related death, migration, and secondary procedures were assessed. Aneurysmal involvement of the iliacs as well as neck length and angulation was compared between groups. Results: Perioperative morbidity (P = 1.000), mortality (P = .4603), and extent of iliac involvement did not differ between groups (P = .2260). The necks in small AAA were longer (P = .0028) and less angulated (P < .0001). There was no difference in overall survival (P = .6066), freedom from major adverse events (P = .7842), endoleak, (P = .1832), migration (P = .5765), aneurysm-related death (P = .4728), or need for secondary procedures (P = .2323). Conclusion: Under controlled conditions of patient and device selection, there is no significant difference in outcome for EVAR of small versus large AAA.

In vitro assessment of aortic stent-graft integrity following exposure to Onyx liquid embolic agent

PURPOSE

Endovascular stent-grafts are increasingly being used for treatment of abdominal and thoracic aortic aneurysms. Postprocedural complications include development of endoleaks. Recently, an embolic agent known as Onyx has been employed to treat type II endoleaks. Onyx is a biocompatible copolymer dissolved in dimethyl sulfoxide (DMSO). Although DMSO is known to damage some angiographic catheters, little is known concerning whether this compound damages stent-graft material. The current study was undertaken to directly explore this issue.

MATERIALS AND METHODS

Four stent-grafts were evaluated: the Excluder, Zenith, AneuRx, and Talent. Stent-grafts were incubated for 24 hours at 37 degrees C under each of the following conditions: DMSO alone, 50/50 mixture of DMSO/Onyx, mixture of 1 part 50/50 DMSO/Onyx and 9 parts whole blood, and untreated control. Stent-grafts were microdissected into 15-mm sections, after which they were evaluated with scanning electron microscopy.

RESULTS

No appreciable differences between stent-grafts exposed to DMSO and untreated controls were seen. Although liquid embolic agent was seen coating stent-grafts exposed to a 50/50 mixture of DMSO and Onyx, no evidence of fiber breakdown was noted. Stent-grafts exposed to DMSO/Onyx/whole blood demonstrated a thin coating of clot and Onyx without visual evidence of fiber compromise.

CONCLUSIONS

The current study provides compelling evidence that short-term exposure of endograft material to DMSO, DMSO/Onyx, or DMSO/Onyx/whole blood is not associated with acute structural compromise of four commonly used aortic endografts. Future in vivo studies will help to further establish the safety of this agent.

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.

Model for the reconfiguration of specialized vascular services

Background

This article built on previous work to develop an algorithm for elective abdominal aortic aneurysm (AAA) repair and carotid endarterectomy (CEA), with the aim of improving patient survival by regionalization of services. Vascular procedures were used as an example of specialized surgical services.

Methods

A model was generated based on a national data set that incorporated the statistical demonstration of procedural safety, hospital annual surgical case volume, and travel distance and time. Elective AAA repair was used to construct a hub-and-spoke model that was tested against CEA. The impact of the model was quantified in terms of mortality rates, and travel distance and time.

Results

Only 48 vascular hubs were required to provide adequate coverage in England, with the majority of patients travelling for less than 1 h to access inpatient vascular surgery. The model predicted a reduction in the number of deaths from elective surgery for AAA (P &lt; 0·001) and CEA (P = 0·016).

Conclusion

Adoption of this strategic model may lead to improved outcome after AAA and CEA. It could be used as a model for the regionalization of specialized surgery. The model does not take into account the complexity of providing a comprehensive vascular service in every locality.

Noninvasive vascular ultrasound elastography applied to the characterization of experimental aneurysms and follow-up after endovascular repair

Experimental and simulation studies were conducted to noninvasively characterize abdominal aneurysms with ultrasound (US) elastography before and after endovascular treatment. Twenty three dogs having bilateral aneurysms surgically created on iliac arteries with venous patches were investigated. In a first set of experiments, the feasibility of elastography to differentiate vascular wall elastic properties between the aneurismal neck (healthy region) and the venous patch (pathological region) was evaluated on six dogs. Lower strain values were found in venous patches (p < 0.001). In a second set of experiments, 17 dogs having endovascular repair (EVAR) by stent graft (SG) insertion were examined three months after SG implantation. Angiography, color Doppler US, examination of macroscopic sections and US elastography were used. The value of elastography was validated with the following end points by considering a solid thrombus of a healed aneurysm as a structure with small deformations and a soft thrombus associated with endoleaks as a more deformable tissue: (1) the correlation between the size of healed organized thrombi estimated by elastography and by macroscopic examinations; (2) the correlation between the strain amplitude measured within vessel wall elastograms and the leak size; and (3) agreement on the presence and size of endoleaks as determined by elastography and by combined reference imaging modalities (angiography + Doppler US). Mean surfaces of solid thrombi estimated with elastography were found correlated with those measured on macroscopic sections (r = 0.88, p < 0.001). Quantitative strain values measured within the vessel wall were poorly linked with the leak size (r = 0.12, p = 0.5). However, the qualitative evaluation of leak size in the aneurismal sac was very good, with a Kappa agreement coefficient of 0.79 between elastography and combined reference imaging modalities. In summary, complementing B-scan and color Doppler, noninvasive US elastography was found to be potentially a relevant tool for aneurismal follow-up after EVAR, provided it allows geometrical and mechanical characterizations of the solid thrombus within the aneurismal sac. This elasticity imaging technique might help detecting potential complications during follows-up subsequent to EVAR.

Long-term cardiac outcome in high-risk patients undergoing elective endovascular or open infrarenal abdominal aortic aneurysm repair

OBJECTIVES

To assess long-term outcome of patients at high cardiac risk undergoing endovascular or open AAA repair.

METHODS

Patients undergoing open or endovascular infrarenal AAA repair with >or=3 cardiac risk factors and preoperative cardiac stress testing (DSE) at 2 university hospitals were studied. Main outcome was cardiac event free and overall survival. Multivariate Cox regression analysis was used to evaluate the influence of type of AAA repair on long-term outcome.

RESULTS

In 124 patients (55 endovascular, 69 open) the number and type of cardiac risk factors, medication use and DSE results were similar in both groups. In multivariable analysis, adjusting for cardiac risk factors, stress test results, medication use, and propensity score endovascular repair was associated with improved cardiac event free survival (HR 0.54; 95% CI 0.30-0.98) but not with an overall survival benefit (HR 0.73; 95% CI 0.37-1.46). Importantly, statin therapy was associated with both improved overall survival (HR 0.42; 95% CI 0.21-0.83) and cardiac event free survival (HR 0.45; 95% CI 0.23-0.86).

CONCLUSIONS

The perioperative cardiac benefit of endovascular AAA repair in high cardiac risk patients is sustained during long-term follow-up provided patients are on optimal medical therapy but it is not associated with improved overall long-term survival.

EVAR and complex anatomy: an update on fenestrated and branched stent grafts

Endovascular aneurysm repair (EVAR) offers a minimally invasive treatment to patients with improved short-term and similar mid-term results compared to conventional, open repair (OR). EVAR is preferred by patients due to the reduction of surgical trauma. Approximately 20% of patients have aneurysm neck morphology which is inadequate for a standard stent graft and requires the endograft to cross vital aortic side branches to achieve a seal. This chapter describes the evolution of three types of devices, namely the fenestrated and branched stent grafts as well as the chimney grafts. These stent grafts incorporate vital aortic side branches in the repair, thereby increasing the applicability of EVAR which may improve the overall results.

Screening for abdominal aortic aneurysm--areas where information is still inadequate

Abdominal aortic aneurysm (AAA) fulfils the criteria for a disease suitable for screening. However, important aspects need to be further analysed; the optimal age of the male population considered for screening has not yet been established, and whether women or specific high risk groups would benefit from screening has not been sufficiently evaluated. The impact of the current shift toward a high proportion of AAA repair done with endovascular technique and the long-term effect on QoL are additional issues that have not been adequately studied. Furthermore, therapeutic options for small AAA as well as secondary prevention programmes have to be developed.

Longitudinal Outcomes After Endovascular Repair of Abdominal Aortic Aneurysms

Objective: Endovascular abdominal aneurysm repair (EVAR) is increasingly used, but there is insufficient evaluation of long-term outcomes. Method: Retrospective cohort study using the linked Washington State hospital discharge database. Result: 3,350 patients underwent elective repair of AAA (1181 EVAR) between 2000 and 2005. EVAR patients were older and had higher comorbidity scores. The 30-day readmission rate after EVAR was 11.6%. The 30-day readmissions included cardiac complications (18.5%) and device complications (10.4%). 46% of the 30-day readmissions after EVAR underwent procedures: abdominal/ iliac angiography (7.4%), angioplasty (8.9%), and device revision (8.2%). Mean time to late interventions was 611 days. Conclusion: Readmission, reintervention, and complication rates after EVAR occur more commonly than previously described. Cardiac complications were the most common readmission. Almost half of the 30-day readmissions required a secondary intervention. Long-term complications after EVAR occurred before two years. Population-based assessment may be more reflective of “real world” complication rates after EVAR.

Predictors of adverse events after endovascular abdominal aortic aneurysm repair: A meta-analysis of case reports

Introduction

Endovascular abdominal aortic aneurysm repair is a life-saving intervention. Nevertheless, complications have a major impact. We review the evidence from case reports for risk factors of complications after endovascular abdominal aortic aneurysm repair.

Case presentation

We selected case reports from PubMed reporting original data on adverse events after endovascular abdominal aortic aneurysm repair. Extracted risk factors were: age, sex, aneurysm diameter, comorbidities, re-interventions, at least one follow-up visit being missed or refusal of a re-intervention by the patient. Extracted outcomes were: death, rupture and (non-)device-related complications.

In total 113 relevant articles were selected. These reported on 173 patients. A fatal outcome was reported in 15% (N = 26) of which 50% came after an aneurysm rupture (N = 13). Non-fatal aneurysm rupture occurred in 15% (N = 25). Endoleaks were reported in 52% of the patients (N = 90). In half of the patients with a rupture no prior endoleak was discovered during follow-up. In 83% of the patients one or more re-interventions were performed (N = 143). Mortality was higher among women (risk ratio 2.9; 95% confidence interval 1.4 to 6.0), while the presence of comorbidities was strongly associated with both ruptures (risk ratio 1.6; 95% confidence interval 0.9 to 2.9) and mortality (risk ratio 2.1; 95% confidence interval 1.0 to 4.7). Missing one or more follow-up visits (≥1) or refusal of a re-intervention by the patient was strongly related to both ruptures (risk ratio 4.7; 95% confidence interval 3.1 to 7.0) and mortality (risk ratio 3.8; 95% confidence interval 1.7 to 8.3).

Conclusion

Female gender, the presence of comorbidities and at least one follow-up visit being missed or refusal of a re-intervention by the patient appear to increase the risk for mortality after endovascular abdominal aortic aneurysm repair. Larger aneurysm diameter, higher age and multimorbidity at the time of surgery appear to increase the risk for rupture and other complications after endovascular abdominal aortic aneurysm repair. These risk factors deserve further attention in future studies.

Management of patients with concomitant lung cancer and abdominal aortic aneurysm

BACKGROUND

Management of patients with an abdominal aortic aneurysm (AAA) and malignancy is challenging. We aimed to define the coincidence of AAA and lung cancer and to determine a treatment strategy.

METHODS

The outcomes for patients diagnosed with AAA and lung cancer between 1991 and 2004 at our institution were reviewed retrospectively.

RESULTS

We identified 75 patients with both lesions among 1,096 AAA and 1,875 lung cancer patients. Survival correlated with cancer stage; only 3 deaths were directly attributable to the patient's AAA. Of 59 patients who did not have AAA repair at the time of cancer diagnosis, 12 were repaired. Twenty-seven of those 59 patients had a 5.0-cm or larger AAA; only 1 patient with a 7.5-cm AAA had a rupture 5 months after thoracotomy and died.

CONCLUSIONS

The co-existence of AAA and lung cancer is not rare; prognosis is poor and largely determined by the lung cancer stage. Open or endovascular repair of AAA rarely is justified in patients with advanced disease unless the AAA is symptomatic or large (>7 cm). Treatment for AAAs greater than 5.5 cm should be based on stage, histology, and patient comorbidities.

Impact of the introduction of endovascular aneurysm repair in high-risk patients on our practice of elective treatment of infrarenal abdominal aortic aneurysms

The aim of this work was to evaluate, in terms of activity and immediate postoperative results, the modifications of our elective surgical treatment of infrarenal abdominal aortic aneurysms (AAAs) resulting from the use of stent grafts to treat AAAs, following the recommendations issued by the French Health Products Safety Agency (AFSSAPS) in December 2003. This monocentric and retrospective study used the clinical data of patients operated on for asymptomatic AAA between January 2001 and December 2006. Endovascular treatment of AAAs with aortic stent grafts was introduced in our current practice in January 2004, following the recommendations of the AFSSAPS (high-risk patients for open surgery presenting with an AAA > or =50 mm). Group I was composed of patients operated on between January 2001 and December 2003 according to the standard open technique. Group II was composed of patients operated on between January 2004 and December 2006 with either standard open surgery or endovascular surgery. The main criteria of evaluation were the number of operated patients, their American Society of Anesthesiology (ASA) score of surgical risk, and the intrahospital morbidity and mortality. The number of treated patients significantly increased between these two periods (group I n = 49, group II n = 88, with 38 endovascular treatments; p < 0.001), without any changes in average age (70 vs. 72 years), percentage of men (93.7% vs. 95.5%), and mean AAA size (57.8 vs. 56 mm) between the two groups. ASA scores were significantly higher in group II (ASA III and IV, group I = 20.4% vs. group II = 55.7%; p < 0.0001), whereas the intrahospital mortality rate (4.1% vs. 3.4%) and the rate of major postoperative complications (16.3% vs. 11%) have remained stable. In group II, the median duration of hospitalization was significantly reduced (12 vs. 9 days, p < 0.001). In conclusion, in our center, following the AFSSAPS recommendations, the introduction of endovascular treatment has enabled us to electively treat a greater number of AAA patients with higher surgical risk, without aggravating the immediate postoperative results.

Endovascular Abdominal Aortic Aneurysm Repair: A Community Hospital's Experience

Endovascular abdominal aortic aneurysm repair (EVAR) has become the first-line approach for the treatment of abdominal aortic aneurysms. Outcomes outside of tertiary care settings remain unknown. The purpose of this study is to report the midterm outcomes of EVAR in a community hospital. A retrospective review of 75 elective, consecutive EVARs performed at a single nonacademic community hospital was performed. There were no conversions to open repair during or after endovascular repair. The mean follow-up was 18 months. There were no postoperative ruptures or aneurysm-related deaths. At 24 months, freedom from aneurysm-related death was 100%, freedom from secondary interventions was 91%, and freedom from endoleak was 69%. EVAR in the community setting is a safe and durable procedure, even in a medically high-risk population. Comparable outcomes can be achieved to tertiary care centers, in carefully selected patients with favorable anatomy.

Regionalization of abdominal aortic aneurysm repair: evidence of a shift to high-volume centers in the endovascular era

INTRODUCTION

Since the early 1990s, many studies have shown lower mortality for abdominal aortic aneurysm (AAA) repair at high-volume centers compared with low-volume centers. The introduction of endovascular AAA repair (EVAR) also has changed the practice of AAA repair. The goal of this study was to determine if regionalization of AAA repair occurred in the United States. Etiologic factors were examined in addition to any reduction in operative mortality rates.

METHODS

Patient discharges of nonruptured AAA repair were identified from the Nationwide Inpatient Sample between 1998 and 2004. Hospitals were stratified by yearly AAA surgical volume of low (< or =17 cases), medium (18 to 50), and high (>50).

RESULTS

A total of 46,901 patients underwent AAA repair (72.7% open vs 27.3% endovascular). The percentage of AAA repairs performed at both low-volume (36.2% to 24.3%) and medium-volume (51.0% to 44.8%) centers fell; whereas, the percentage performed at high-volume centers nearly tripled (12.9% vs 30.9%). In 1998 there were 10 high-volume centers; by 2004 this had increased to 26. The number of low-volume centers decreased, from 412 to 328. EVAR was more rapidly adopted by high-volume centers compared with low-volume centers. By 2004, 64.3% of AAA repairs at high-volume centers were done with endovascular techniques compared with 31.8% in low-volume centers. A concurrent reduction occurred in patient mortality, from 4.4% in 1998 to 2.5% in 2004 (P < .0001).

CONCLUSION

Between 1998 and 2004, a trend towards the regionalization of AAA repair to high-volume centers occurred. Nearly one-third of all AAA repairs were performed at high-volume centers. There was a concurrent increase in the frequency of endovascular AAA repair, especially at high-volume centers. During this period of regionalization of AAA repair to high-volume centers, patient mortality after AAA repair decreased by 23%. Thus, the observed regionalization of AAA repair and the reduction in short-term patient mortality for this operation may be explained by increased utilization of endovascular technologies at high-volume centers.

Contemporary Analysis of Descending Thoracic and Thoracoabdominal Aneurysm Repair

Background— Endovascular repair of thoracic aneurysm has demonstrated low risks of mortality and spinal cord ischemia (SCI), but few large series have been published on endovascular thoracoabdominal aneurysm repair, and reports suffer from a lack of accurate comparison with similar open surgical procedures.

Methods and Results— A consecutive cohort of patients with thoracic and thoracoabdominal aneurysms treated electively with endovascular repair (ER) or surgical repair (SR) techniques between 2001 and 2006 were analyzed. The association between repair technique and SCI was evaluated with univariable analysis. Adjustments for potential confounders and for the propensity to receive ER or SR were also performed in multivariable analysis. A total of 724 patients (352 ER, 372 SR) underwent repair. The mean age was 67 years, and 65% were male. ER patients were on average 9 years older ( P <0.001), had more comorbid conditions, and more frequently had prior distal repair ( P <0.001) or underwent a type I or IV repair. SR patients more commonly had chronic dissection or required type II or type III repairs ( P <0.001). Mortality at 30 days (5.7% ER versus 8.3% SR, P =0.2) and 12 months (15.6% ER versus 15.9% SR, P =0.9) was similar. A borderline difference in SCI was found between repair techniques: 4.3% of ER and 7.5% of SR patients ( P =0.08) had SCI. In patients with ER, prior distal aortic operation was associated with the development of SCI in univariable analysis (odds ratio 4.1, 95% confidence interval 1.4 to 11.7). Multivariable analysis showed that the type of required repair (type I, II, III, or IV) was the primary factor associated with the development of SCI in ER and SR patients.

Conclusion— No significant difference in the incidence of mortality or SCI was found between ER and SR techniques. The strongest factor associated with SCI remains the extent of the disease. Further studies are indicated to compare ER with patients considered eligible for SR.

Limited feasibility in endovascular aneurysm repair using currently available graft in Korea

Despite the wide acceptance of endovascular aneurysmal repair in patients with abdominal aortic aneurysm (EVAR), stringent morphologic criteria recommended by manufacturers may preclude this treatment in patients with AAA. The purpose of this study was to investigate how many patients are feasible by Zenith and Excluder stent graft system, which are available in Korea. Eighty-two AAA patients (71 men, mean age 70 yr) who had been treated surgically or medically from January 2005 to December 2006 were included. Criteria for morphologic suitability (MS) were examined to focus on characteristics of aneurysm; proximal and distal landing zone; angulation and involvement of both iliac artery aneurysms. Twenty-eight patients (34.1%) were feasible in Zenith stent graft and 31 patients (37.8%) were feasible in Excluder. The patients who were excluded EVAR had an average of 1.61 exclusion criteria. The main reasons for exclusion were an unfavorable proximal neck (n=34, 41.5%) and problem of distal landing zone (n=25, 30.5%). There was no statistical significance among gender, age or aneurysm size in terms of MS. Only 32 patients (39%) who had AAA were estimated to be suitable for two currently approved grafts by strict criteria. However, even unfavorable AAA patients who have severe co-morbidities will be included in EVAR in the near future. Therefore, more efforts including fine skill and anatomical understanding will be needed to meet these challenging cases.

Intraoperative DynaCT detection and immediate correction of a type Ia endoleak following endovascular repair of abdominal aortic aneurysm

Reintervention following endovascular aneurysm repair (EVAR) is required in up to 10% of patients at 30 days and is associated with a demonstrable risk of increased mortality. Completion angiography cannot detect all graft-related anomalies and computed tomographic angiography is therefore mandatory to ensure clinical success. Intraoperative angiographic computed tomography (DynaCT; Siemens, Germany) utilizes cone beam reconstruction software and flat-panel detectors to generate CT-like images from rotational angiographic acquisitions. We report the intraoperative use of this novel technology in detecting and immediately treating a proximal anterior type Ia endoleak, following an endovascular abdominal aortic repair, which was not seen on completion angiography. Immediate evaluation of cross-sectional imaging following endograft deployment may allow for on-table correction of clinically significant stent-related complications. This should both improve technical success and minimize the need for early secondary intervention following EVAR.

More patients are treated for nonruptured abdominal aortic aneurysms, but the proportion of women remains unchanged

BACKGROUND

Large variations in the intervention rates for ruptured and nonruptured abdominal aortic aneurysm (AAA) over time have been reported, both decreasing and increasing numbers. Women have been reported to constitute an increasing proportion of patients treated for several manifestations of cardiovascular disease; whether a similar trend is true for AAA is not well understood. This study investigated recent temporal trends in a complete national register regarding the number and type of procedure performed for AAA, and outcome, with special emphasis on gender differences.

METHODS

Data for all individuals treated for nonruptured or ruptured AAA in Sweden (1990 to 2005) were obtained from the Swedish National Board of Health and Welfare (NBHW). A total of 14369 individuals were identified; 2327 (16%) were women. Date and type of intervention, date and cause of death, age, and sex were included in the statistical model.

RESULTS

There was a relative annual increase in interventions for nonruptured AAA; 4% for women (P < .0001) and 2% for men (P < .0001). No significant trends were observed for interventions for rupture during the observation period. No significant increase in the proportion of women was recorded for nonrupture (17%) or rupture (15%). Women had higher crude 30-day mortality rate than men after treatment for both nonruptured (5.7% vs 4.9%) and ruptured (41.9% vs 36.8%) AAA. In a logistic regression model, survival improved over time after intervention for nonrupture (P < .0001) and rupture (P < .0001). Increasing age (P < .0001 for both nonrupture and rupture) but not sex (P = .49 for non rupture and P = .42 for rupture) had a negative influence on mortality.

CONCLUSION

Interventions for nonruptured but not for ruptured AAA increased over time, with an expected rapid increase of endovascular repair in the nonruptured group. The unchanged fraction of women over time possibly reflects the true distribution of AAA between the sexes. The outcome after treatment for both nonruptured and ruptured AAA improved, as anticipated, over time. No increase in mortality among women was recorded after adjustment for age.

Comparison of the effects of open and endovascular aortic aneurysm repair on long-term renal function using chronic kidney disease staging based on glomerular filtration rate

OBJECTIVE

It has been suggested that endovascular aneurysm repair (EVAR) in concert with serial contrast-enhanced computed tomography (CT) surveillance adversely impacts renal function. Our primary objectives were to assess serial renal function in patients undergoing EVAR and open repair (OR) and to evaluate the relative effects of method of repair on renal function.

METHODS

A thorough retrospective chart review was performed on 223 consecutive patients (103 EVAR, 120 OR) who underwent abdominal aortic aneurysm (AAA) repair. Demographics, pertinent risk factors, CT scan number, morbidity, and mortality were recorded in a database. Baseline, 30- and 90-day, and most recent glomerular filtration rate (GFR) were calculated. Mean GFR changes and renal function decline (using Chronic Kidney Disease [CKD] staging and Kaplan-Meier plot) were determined. EVAR and OR patients were compared. CKD prevalence (>or=stage 3, National Kidney Foundation) was determined before repair and in longitudinal follow-up. Observed-expected (OE) ratios for CKD were calculated for EVAR and OR patients by comparing observed CKD prevalence with the expected, age-adjusted prevalence.

RESULTS

The only baseline difference between EVAR and OR cohorts was female gender (4% vs 12%, P = .029). Thirty-day GFR was significantly reduced in OR patients (P = .047), but it recovered and there were no differences in mean GFR at a mean follow-up of 23.2 months. However, 18% to 39% of patients in the EVAR and OR groups developed significant renal function decline over time depending on its definition. OE ratios for CKD prevalence were greater in AAA patients at baseline (OE 1.28-3.23, depending upon age group). During follow-up, the prevalence and severity of CKD increased regardless of method of repair (OE 1.8-9.0). Deterioration of renal function was independently associated with age >70 years in all patients (RR 2.92) and performance of EVAR compared with OR (RR 3.5) during long-term follow-up.

CONCLUSIONS

Compared with EVAR, OR was associated with a significant but transient fall in GFR at 30 days. Renal function decline after AAA repair was common, regardless of method, especially in patients >70 years of age. However, the renal function decline was significantly greater by Kaplan-Meier analysis in EVAR than OR patients during long-term follow-up. More aggressive strategies to monitor and preserve renal function after AAA repair are warranted.

Non-Operative or Medical Management of Abdominal Aortic Aneurysm

Non-operative management of patients with abdominal aortic aneurysm (AAA) is required for several different reasons. Since these patients have an increased risk of cardiovascular death therapy to reduce cardiovascular events is essential. Treatment is in line with the medical management of coronary artery disease including smoking cessation, statins and anti-platelet therapy. Some of these therapies also will slow aneurysm growth, which is a target in the management of patients with small AAA. As yet there is no targeted therapy that reduces aneurysm growth, but there is active research in this area. Medical management also is required to reduce peri-operative risks, stabilise endovascular aneurysm repair and minimise the risk of rupture in those with large AAA unfit for aneurysm repair.