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

[Abdominal aortic aneurysm--rupture of the anterior wall]

INTRODUCTION

An aneurysm is a focal dilatation of an artery (aorta), involving an increase in diameter of at least 50% as compared to the expected normal diameter (over 3 cm). Abdominal aortic aneurysms (AAA) cause thousands of deaths every year, many of which can be prevented with timely diagnosis and treatment. AAA can be asymptomatic for many years, but in one third of patients whose aneurysm ruptured, the mortality rate is 90%. In the past, palpation of the abdomen was the preferred method for identifyng AAA. However, diagnostic imaging techniques, such as ultrasonography and computed tomography are more accurate and offer opportunities for early detection of AAA.

CASE REPORT

This paper is a case report of an 83-year-old female patient. She was admitted due to severe pain in the abdomen. We already knew about the AAA (from her medical history). After using all available diagnostic procedures, rupture or disection of the AAA were not comfirmed. The patient underwent emergency surgery. During the operation, rupture of the anterior wall of the aneurysm was found. The anterior wall was filled with parietal thrombus, which hermetically closed the perforation. The patient was successfully operated and recovered.

CONCLUSION

The aim of this case report was to point out that our diagnostic procedures failed to confirm the rupture of AAA. We decided to apply surgical treatment, based on medical experience, clinical findings, ultrasonography and computed tomography and during operation rupture of AAA was confirmed Patients with an already diagnosed AAA, or patients with clinical picture of rupture or dissection, are in urgent need for surgery, no matter what diagnostic tools are being used.

Positive fluid balance is associated with complications after elective open infrarenal abdominal aortic aneurysm repair

BACKGROUND

Open abdominal aortic aneurysm (AAA) repair is associated with cardiac and respiratory complications and an overall mortality rate of 2 to 8%. We hypothesised that excessive fluid administration during the perioperative period contributes to complications and poor outcome after AAA repair.

METHODS

This was a retrospective cohort study. Medical records were analysed for fluid balance and complications in 100 consecutive patients treated by open AAA repair at a single centre between 2002-2005. Mortality and all major adverse events (MAE) such as myocardial infarction (MI), cardiac arrhythmia (Arr), pulmonary oedema (PO), pulmonary infection (PI), and acute renal failure (ARF) were included in the analysis. Level of care and hospital stay, were also recorded.

RESULTS

There were no in-hospital deaths. MAE occurred in 40/100 (40%): MI (6%); Arr (14%); PO (14%); PI (25%); ARF (8%). Complications were not predicted by preoperative cardiovascular risk factors, operative and clamp time, or blood loss. Patients with complications had significantly greater cumulative positive fluid balance on postoperative day 0 (p<0.01), day 1 (p<0.05), day 2 (p<0.03) and day 3 (p<0.04). This relationship also existed for individual complications such as MI, and pulmonary oedema. These patients had significantly longer ICU/HDU (p<0.002) and hospital stay (p<0.0001).

CONCLUSIONS

Serious complications are common after elective open AAA repair, and we have shown that positive fluid balance is predictive of major adverse events increased HDU/ICU and overall hospital stay.

Medical Management of Abdominal Aortic Aneurysm

Medical 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. Currently there is no proven focused therapy that reduces aneurysm growth, but the emerging strategies are discussed. Medical management also is required to reduce peri-operative risks and stabilise endovascular aneurysm repair. Whilst some of the therapies targeting cardiovascular risk reduction may be helpful, other emerging strategies are discussed.

Vivid bad outcome influences the decisions of older adults about treatment timing: a randomized field experiment with an abdominal aortic aneurysm analog

In balancing the risk of rupture from an asymptomatic abdominal aortic aneurysm (AAA) against the risk of perioperative mortality, data-based guidelines recommend surgical repair when the AAA diameter reaches 5.5 cm, whereas smaller AAAs should be followed with periodic surveillance. Previous work with vascular surgeon subjects and a computer-based AAA analog simulation showed that, even when constantly updated with the relevant statistics, experiencing a prior bad watchful waiting outcome shortened the time until they made the decision to operate. Using the same simulation, this field experiment enrolled healthy older volunteers (n = 107). Participants were randomly assigned to experience either a bad outcome demonstration with an expanding balloon that bursts (experimental) or an expanding, nonbursting balloon (control). Participants then made decisions about how many times to allow the balloon to expand before opting-out of the simulation. The main outcome measure was the amount of time participants continued watchful waiting before opting-out. A Cox-regression analysis assessed the likelihood of opting-out after each expansion while controlling for censoring and important covariates, including baseline anxiety, uncertainty attitudes, and risk preferences. The bad outcome demonstration group ended the simulation significantly earlier than did the control subjects (Hazard ratio: 1.98; 95% CI: 1.05-3.74). These results extend previous findings from vascular surgeons to older adults at higher risk for AAA. The preceding bad outcome influenced subsequent decisions, even when statistical risk information was readily available. The influence of recent experience on medical decision making by patients with life-threatening conditions may be under-appreciated.

The Relationship Between Volume and Outcome Following Elective Open Repair of Abdominal Aortic Aneurysms (AAA) in 131 German Hospitals

OBJECTIVES

Several studies indicate that high-volume hospitals have better results in open repair of unruptured abdominal aortic aneurysms (AAA). Up to now no studies had addressed this question in German hospitals.

DESIGN

Post-hoc-analysis from a prospective physician-led registry.

MATERIAL AND METHODS

Since 1999, the German Society for Vascular Surgery has conducted a prospective registry for open and endovascular repair of AAAs. This study includes 131 hospitals who conducted n=10163 elective open repairs for unruptured AAA between 1999 to 2004. All perioperative variables including annual volume as a continuous variable were analysed in a step-wise logistic regression model. In order to define a threshold annual volume an additional logistic regression analysis was performed by use of annual volume groups (0-9, 10-19, 20-29, 30-39, 40-49, 50 or more). The relationship between annual volume and further outcome parameters (length of procedure, blood transfusion, length of stay) were also analyzed.

RESULTS

The overall mortality rate was 3.2%. The stepwise logistic regression model identified the following predictors of an increased perioperative mortality: age (OR 1.084, 95% CI 1.066-1.102), AAA diameter (OR 1.008, 95% CI 1.001-1.016), length of procedure (OR 1.008, 95% CI 1.006-1.009), ASA-Score (OR 2.636, 95% CI 2.129-3.264), suprarenal clamping (OR 1.447, 95% CI 1.008-2,078), blood transfusion (OR 1.786, 95% CI 1.268-2.514). Annual volume was moderately predictive (OR 1.003, 95% CI 1-1.006) but failed to reach statistical significance (p=0.07). The analysis of volume groups identified a significantly higher risk for hospitals with an annual volume of 1-9 AAA-repairs by comparison to hospitals with an annual volume of 50 or more AAA-repairs (OR 1.903, 95% CI 1.124-3.222). Operations at low volume hospitals were also longer (p<0.001), with an extended postoperative stay (p<0.001) and a higher transfusion rate (p<0.001).

CONCLUSIONS

Patient's age, ASA classification, AAA diameter, length of procedure, suprarenal clamping and blood transfusion are predictive variables for an increased perioperative mortality in elective open AAA repair. Mortality is also increased by a low annual volume. Further studies are needed to examine whether these data are applicable to all German hospitals.

Nouvelle législation portant sur les soins courants: rappel des difficultés passées

OBJECTIVE

The regulatory framework of clinical research in France was recently modified substantially, in part to transpose into French law directive 2001/20/EC of the European Parliament and Council, which concerns only drug trials. The revision also covered research on "human beings" (Public Health L. 2004-806, 2006-450), on biological samples (revision of bioethics, L. 2004-800) and on data (the so-called CNIL act, L. 2004-801). The value of this set of texts (statutes, decrees, and regulations) is that it diversifies and clarifies the different forms of clinical research.

METHODS

This article describes the painful progression of important public health studies, most often with "academic" sponsors.

RESULTS

The 5 studies described here managed to overcome a variety of obstacles posed by the pre-2004 regulations.

COMMENTS

To understand the new provisions, it is useful to recall the difficulties, imprecision and inaptness of the earlier regulations.

The effects of prophylactic coronary revascularization or medical management on patient outcomes after noncardiac surgery - a meta-analysis

PURPOSE

The benefits of prophylactic coronary revascularization for patients undergoing noncardiac surgery are uncertain. The purpose of this study was to systematically evaluate the effect of coronary revascularization and medical management on short- and long-term outcomes after noncardiac surgery.

METHOD

Ten electronic databases including MEDLINE and EMBASE (1980 to February 2006), and bibliographies of included articles were searched without language restrictions. Studies comparing effects of coronary revascularization and medical management before noncardiac surgery were included. Patient outcome data including perioperative mortality, myocardial infarction, long-term mortality, or late adverse cardiac events were extracted and entered into a meta-analysis.

RESULTS

The quality of published evidence was modest, comprising one randomized controlled trial and six retrospective studies. A total of 3,949 patients undergoing high-risk noncardiac surgery were included in the quantitative analysis. There was no significant difference between coronary revascularization and medical management groups with regards to postoperative mortality and myocardial infarction; the odds ratios (95% confidence intervals) were 0.85 (0.48-1.50) and 0.95 (0.44-2.08), respectively. There were no long-term outcome benefits associated with prophylactic coronary revascularization; the odds ratios (95% confidence intervals) were 0.81 (0.40-1.63) and 1.65 (0.70-3.86) for long-term mortality and late adverse cardiac events, respectively.

CONCLUSION

In patients with stable coronary artery disease, prophylactic coronary revascularization before high-risk noncardiac surgery does not confer any beneficial effects, when compared with optimized medical management, in terms of perioperative mortality, myocardial infarction, long-term mortality, or adverse cardiac events.

Isolated iliac artery aneurysms: endovascular versus open elective repair

OBJECTIVE

To compare endovascular and open repair of isolated or solitary iliac artery aneurysms (SIAAs).

METHODS

We present the results of 55 patients with 58 SIAAs that were treated between January 1998 and December 2005 in two European university hospitals. In one center, the standard procedure, if not contraindicated, was endovascular repair, and 32 (58.2%) consecutive patients with 33 SIAAs were treated by using only endovascular techniques (endovascular iliac aneurysm repair; EVIAR). In the second center, 23 (41.8%) consecutive patients with 25 SIAAs were treated by conventional surgical techniques because advanced endovascular skills were not available before late 2005. EVIAR included coil embolization of the hypogastric artery in 13 of the 33 cases with aneurysmal involvement of the internal iliac artery. In the "open" group of patients, midline laparotomy and a transperitoneal approach with bifurcated aortoiliac graft replacement was performed in 4 cases, and a lower lateral abdominal incision with a retroperitoneal approach and iliac replacement was performed in 19 cases.

RESULTS

The mean follow-up period was similar in both groups (EVIAR, 35.3 +/- 21.3 months; open, 31.3 +/- 19.9 months). The two groups of patients had similar demographic and clinical characteristics compared with previous reported series, and data analysis revealed a statistically significant difference between the two groups only in hypertension. The early and mid-term outcomes and especially the 3-year primary patency rates were also similar between the two groups (EVIAR, 97%; open, 100%). In the EVIAR group, there was no evidence of endoleaks, kinking, or graft migration, and 26 aneurysms remained stable, whereas in 7 aneurysms a slight decrease in size (>10% in diameter) was observed. Comparison of operative time, intraoperative blood loss, and postoperative hospital stay revealed significant differences (P < .001) in favor of the endovascular group. Secondary intervention was not necessary in any patient in either group during the entire follow-up period.

CONCLUSIONS

Elective management with endovascular or open techniques of isolated iliac aneurysms can be accomplished with very low morbidity and mortality rates. Better intraoperative and early postoperative outcomes, as well as the durable mid-term results in our EVIAR-treated patients, indicate that endovascular techniques could be offered as first-line therapy of SIAAs.

Impact of randomized trials comparing conventional and endovascular abdominal aortic aneurysm repair on clinical practice

PURPOSE

To report a retrospective study into the effects of trials on clinical decision-making regarding abdominal aortic aneurysm (AAA) patients suitable for both conventional open (OR) and endovascular aneurysm repair (EVAR).

METHODS

A questionnaire was sent to 1400 Dutch surgeons and trainees. Interviewees had to choose between OR and EVAR for AAA patients with and without comorbidity. Specifically, their preferences before and after the publication of 2 randomized trials (EVAR-1 and DREAM) were polled.

RESULTS

Of the 524 (37%) questionnaires returned, 223 (43%) respondents treated AAA patients. Before publication of the trials, 160 (72%) preferred OR for the patient without comorbidity and 169 (76%) preferred EVAR for the patient with comorbidity. In total, 72 (32%) respondents changed their preference after the trials were published; however, there was no overall major shift. Focusing on the different cases revealed that the OR preference was significantly enhanced for the patient without comorbidity (p<0.01), while the EVAR preference was significantly enhanced for the patient with comorbidity (p<0.05).

CONCLUSION

The randomized trials have not induced major overall changes in surgical decision-making for AAA patients suitable for both EVAR and OR.

Fluid-Structure Interaction Analyses of Stented Abdominal Aortic Aneurysms

Rupture of abdominal aortic aneurysms (AAAs) alone is the thirteenth leading cause of death in the United States. Thus, reliable AAA-rupture risk prediction is an important advancement. If repair becomes necessary, the minimally invasive technique of inserting a stent-graft (SG), commonly referred to as endovascular aneurysm repair (EVAR), is a viable option in many cases. However, postoperative complications, such as endoleaks and/or SG migration, may occur. Computational fluid-structure interaction simulations provide physical insight into the hemodynamics coupled with multi-wall mechanics' function as an assessment tool for optimal SG placement and improved device design.

Predictive Factors, Morphologic Effects, and Proposed Treatment Paradigm for Type II Endoleaks after Repair of Infrarenal Abdominal Aortic Aneurysms

PURPOSE

To evaluate the predictive factors and outcome of type II endoleaks after endovascular repair of infrarenal abdominal aortic aneurysms with use of a Zenith endograft.

MATERIALS AND METHODS

Patients classified at high risk were enrolled in a prospective study and evaluated with serial cross-sectional imaging techniques. The effect of a type II endoleak on sac behavior and associated factors were analyzed. Type II endoleaks were categorized as absent, persistent, or transient, and the morphologic effects were determined. Logistic regression and classification tree were used to predict which patients may be at risk for persistent type II endoleaks.

RESULTS

A total of 273 patients were enrolled. Patients were excluded in the absence of a minimum of 6 months digital data or the presence of endoleak not classified as type II. Two hundred four patients met inclusion criteria, with a median follow-up period of 24 months (range, 6-60 months). Early type II endoleak was detected in 35 patients (17%), which resolved spontaneously in 17 cases. There were 18 patients with persistent endoleak, 17 patients with transient type II endoleak, and 169 patients with no endoleak. Aneurysm enlargement was detected in seven patients with persistent endoleak (39%), no patients with transient type II endoleak, and one patient with no endoleak. No variables were predictive of the development of persistent endoleak. The relative risk of aneurysmal growth was 77 with persistent endoleak. Successfully treated persistent endoleaks were not associated with any growth.

CONCLUSIONS

Persistent endoleaks are associated with sac growth. Transient type II endoleaks have a benign course and do not require treatment. Successful treatment of persistent endoleak ameliorates the risk of growth.

Health-related quality of life in survivors of open ruptured abdominal aortic aneurysm repair: A matched, controlled cohort study

OBJECTIVE

The objective of this study was to document the health-related quality of life (HRQOL) for patients who survived operative repair of a ruptured abdominal aortic aneurysm (RAAA) and to compare this with a matched group of patients who survived elective operative repair of an abdominal aortic aneurysm (EAAA).

METHODS

A matched, controlled cohort study of HRQOL was used to compare patients surviving RAAA with an EAAA control group. The study was conducted at two university-affiliated vascular tertiary care referral centers. Survivors of RAAA and EAAA during an 8.5-year period were identified and followed up. The RAAA and EAAA control patients were matched for age, serum creatinine concentration, gender, and duration of follow-up since surgery. HRQOL was measured with the Medical Outcomes Study Short Form-36 Health Survey (SF-36). Scores for the EAAA and RAAA cohorts were also compared with age-corrected SF-36 population scores.

RESULTS

Of 267 patients operated for RAAA during the study period, 130 (49%) survived to hospital discharge. Death after discharge was documented in 35 patients, leaving a potential study population of 95 RAAA survivors. Thirteen were lost to follow-up, seven refused to participate, and four patients were not able to participate. The SF-36 was completed by 71 RAAA patients (75% of surviving RAAA patients). The 71 RAAA survivors and 189 EAAA control patients were similar for seven of eight domains of the SF-36: Physical Function, Role-Physical, Bodily Pain, General Health, Vitality, Mental Health, and Role-Emotional. There was also no difference in the Physical Health Summary and Mental Health Summary scores. The social function component of the SF-36 demonstrated a statistically significant decline in the EAAA group. Both the EAAA and RAAA SF-36 individual and summary scores compared favorably with population norms that were adjusted only for age.

CONCLUSION

Long-term survivors of RAAA enjoy a HRQOL that does not differ significantly from EAAA survivors. Scores for both groups compare favorably with population scores adjusted only for age.

Side-branched AAA stent graft insertion using navigation technology: a phantom study

OBJECTIVE

To evaluate the feasibility of a side-branched stent graft inserted in an artificial abdominal aortic aneurysm (AAA), using navigation technology, and to compare procedure duration and dose of radiation with control trials.

METHODS

A custom-made stent graft was inserted into an artificial AAA using navigation technology in combination with fluoroscopy. The navigation technology was based on three-dimensional visualization of computed tomography data and electromagnetic tracking of microposition sensors. The stent graft had integrated position sensors in side branch and introducer and was guided into proper position with the aid of three-dimensional images. Control trials were performed with fluoroscopy alone.

RESULTS

It was feasible to insert a side-branched stent graft using three-dimensional navigation technology. The navigation-guided trials had a significantly lower X-ray load (p < 0.001), but showed no difference in the duration of the procedures (p = 0.34) as compared with controls.

CONCLUSIONS

Inserting a side-branched stent graft in an artificial AAA using navigation technology is feasible. Side-branched stent grafts and navigation systems may become useful in the endovascular treatment of complicated aortic aneurysms.

Limb Graft Occlusion Following EVAR: Clinical Pattern, Outcomes and Predictive Factors of Occurrence

INTRODUCTION

We reviewed our experience with limb occlusion after EVAR in order (1) to assess the clinical pattern and treatment options (2) to assess outcomes and (3) to identify predictive factors of occurrence.

MATERIALS AND METHOD

Between 1995 and 2005, 460 AAA patients were electively treated with a variety of commercially available stent grafts. There were 369 bifurcated and 91 aortouniiliac grafts (829 limbs). Follow-up included physical examination, plain X-ray, Duplex ultrasonography, and spiral computed tomographic scans at 1, 6, 12 months and annually thereafter. All pertinent data were collected prospectively and analysed retrospectively. The follow-up period ranged from Day 0 to 104 months, with a median follow-up of 23.4 months.

RESULTS

36 limbs in 33 patients (7.2%) occluded between Day 0 and 71 months (average: 9.5 months) after EVAR. Presentation was acute ischemia in 11 cases, rest pain in 9, claudication in ten. Four occlusions remained asymptomatic and two occurred intraoperatively. Treatment was femoro-femoral cross-over graft in 19 cases, axillo-femoral bypass in three, thrombectomy and stent in three, thrombolysis and stent in nine, and conservative in two. One patient (3%) died of multiple organ failure after thrombolysis. There was no amputation. Reocclusions occurred in two patients (6.1%). Multivariate logistic regression showed that kinking (odds ratio [OR] 11.9; confidence interval [CI] 3.39-42.1; p=0.0001), first graft generation (OR 2.87; CI 1.25-6.62; p=0.017) and younger age (OR 1.05; CI 1.00-1.09; p=0.034) were independently related to the occurrence of graft limb occlusion.

CONCLUSION

Acute graft limb occlusion is not rare after EVAR. The frequency of limb occlusion has declined with current stent grafts generation. Although surgery and endovascular treatments are efficient and safe, development of a graft limb kink should lead to aggressive pre-emptive treatment to prevent occlusion.

Long-term postplacement cost after endovascular aneurysm repair

BACKGROUND

Previous studies have demonstrated that the initial hospital cost associated with endovascular aneurysm repair (EVAR) is approximately $20,000. However, the cost of long-term surveillance and secondary procedures is poorly characterized.

METHODS

Between December 1998 and June 2006, 259 patients underwent EVAR for infrarenal aneurysms at a single institution. Follow-up costs were calculated using a relative value unit based hospital cost accounting system, which incorporates departmental direct and indirect costs. Institutional overhead costs were included using a conversion factor. Costs for professional services were determined by a cost-to-charge ratio, and outpatient visits were calculated with a time-based formula. Year 2006 costs were applied to prior years. To minimize costs associated with the early learning curve, the initial 50 EVAR patients between December 1995 and 1998 were excluded. Patients with <1 year follow-up were also excluded. Data are expressed as mean +/- standard error.

RESULTS

The mean follow-up after EVAR for 136 patients was 34.7 +/- 1.8 months. The cumulative 5-year postplacement cost per patient was $11,351. The 27 patients (19.9%) who required secondary procedures had a 5-year cumulative cost of $31,696 compared with $3668 for 109 patients without secondary procedures (8.6-fold increase, P < .05). The 5-year cost for patients with endoleak was $26,739 compared with $5706 for those without endoleak (4.7-fold increase, P < .05). Overall, major cost components were 57.4% for secondary procedures and 32.5% for radiologic studies.

CONCLUSIONS

During a 5-year period, the postplacement cost of EVAR increases the global cost by 44%. The subgroups of patients with endoleaks and those requiring secondary procedures generate a disproportionate share of postplacement costs. Efforts at minimizing cost should emphasize technical and device modifications aimed at reducing endoleaks and the need for secondary procedures.

Fifteen-year follow-up of a randomized clinical trial of ultrasonographic screening for abdominal aortic aneurysms

BACKGROUND

Long-term benefits of screening for abdominal aortic aneurysm (AAA) are uncertain. These are the final results of a randomized controlled screening trial for AAA in men, updating those reported previously. Benefit and compliance over a median 15-year interval were examined.

METHODS

One group of men were invited for ultrasonographic AAA screening, and another group, who received standard care, acted as controls. A total of 6040 men aged 65-80 years were randomized to one of the two groups. Outcome was monitored in terms of AAA-related events (surgery or death).

RESULTS

In the group invited for screening, AAA-related mortality was reduced by 11 per cent (from 1.8 to 1.6 per cent, hazard ratio 0.89) over the follow-up interval. Screening detected an AAA in 170 patients; 17 of these died from an AAA-related cause, seven of which might have been preventable. The incidence of AAA rupture after an initially normal scan increased after 10 years of follow-up, but was still low overall (0.56 per 1000 person-years).

CONCLUSION

Screening with a single ultrasonography scan still conferred a benefit at 15 years, although the results were not significant for this population size. Fewer than half of the AAA-related deaths in those screened positive could be prevented.

REGISTRATION NUMBER

ISRCTN 00079388 (http://www.controlled-trials.com).

Aneurysmen und Dissektionen der thorakalen und abdominellen Aorta

One to four per cent of all deaths in patients over 65 are caused by aneurysmatic diseases of the abdominal or thoracic aorta. For elective surgery in abdominal aneurysms, open surgery and endovascular treatment both demonstrate brilliant overall results. In the thoracic aorta, new endovascular procedures have led to considerable reductions of postoperative morbidity and mortality. Nevertheless, in view of the endovascular procedure's high cost and the still unclear long-term behaviour of the stent device, a second opinion from a specialised centre is an absolute necessity.

Long-Term Single-Center Results with Aneurx Endografts for Endovascular Abdominal Aortic Aneurysm Repair

PURPOSE

To evaluate the long-term single-center results with the AneuRx stent-graft in endovascular abdominal aortic aneurysm (AAA) repair (EVAR).

METHODS

Between December 1996 and August 2003, 212 patients (197 men; mean age 71.3+/-7.0 years) were treated with the AneuRx stent-graft for an infrarenal AAA. Postoperatively, patients were enrolled in a fixed surveillance protocol, and data were prospectively captured into a database.

RESULTS

Graft deployment was successful in 98.6% (209/212). Thirty-day mortality was 2.4%. Median hospital stay was 4.3+/-5.5 days. Median follow-up was 52.0 months (range 1-109); only 1 patient was lost to follow-up. At 9 years, patient survival was 56% and freedom from secondary interventions was 48%. In 68% of cases, these reinterventions were needed for a fixation-related complication, and most of these complications (75%) encompassed the area of the proximal aneurysm neck. Primary clinical success was 37% at 9 years. After secondary interventions, the assisted primary clinical success improved to 73% at 9 years. Freedom from aneurysm-related death was 97% at 1 year and 90% at 9 years.

CONCLUSION

As an alternative to open repair, EVAR with the AneuRx device has low perioperative mortality. Reinterventions are mostly due to fixation-related complications. While the overall mortality risk in this population was 5% per year, annual aneurysm-related death was only 1%. The focus should be on surveillance and reducing the rate of long-term complications, which might be possible with improved proximal stent-graft fixation.

Objective scoring systems of medical risk: A clinical tool for selecting patients for open or endovascular abdominal aortic aneurysm repair

BACKGROUND

Objective scoring systems have been developed for risk stratification of open infrarenal aneurysm repair. To date, none have been applied for the selection of patients who would most benefit from either an open or an endovascular approach. This study assessed the utility of comorbidity-based objective scoring systems for defining subgroups of patients who might most benefit from open or endovascular aneurysm repair.

METHODS

A retrospective database review was performed for the period January 1999 to December 2004 to identify patients who had undergone elective open aneurysm repair (open repair) or elective endovascular aneurysm repair (EVAR). Validation of the Glasgow Aneurysm Score (GAS), the Modified Leiden Score (M-LS), and the Modified Comorbidity Severity Score (M-CSS) was performed for perioperative mortality risk in the open repair group. GAS, M-LS, and M-CSS were then calculated for the EVAR group. Differences in open repair vs EVAR mortalities were evaluated.

RESULTS

During the time period, 558 patients underwent open repair and 304 underwent EVAR. Overall mortality was 4.7% for open repair patients and 2.0% for EVAR. All three scoring systems were validated to our open repair data set (C statistic: GAS, 0.72; M-LS, 0.71; M-CSS, 0.74). A score was calculated for each system that separated patients into groups of either low or high risk of death for open repair. This score (cut point) was 76.5 for the GAS, 5.2 for the M-LS, and 8 for the M-CSS. Analysis of the EVAR population revealed that patients at low medical risk for open repair did not derive statistically significant mortality benefit with EVAR; however, patients at high medical risk for open repair derived significant benefit from EVAR (GAS>76.5 mortality: open repair, 7.8%; EVAR, 1.9% [P<.01]; M-LS mortality: open repair, 8.1%; EVAR, 2.5% [P<.01]; and M-CSS mortality: open repair, 10.3%; EVAR, 3.4% [P<.025]). Despite a very small number of deaths (n=6), receiver operator curve analysis identified M-LS and M-CSS as having some predictive ability for mortality risk with EVAR (C statistic: M-LS, 0.70; M-CSS, 0.69).

CONCLUSION

Three validated objective scoring systems can be used to categorize patients into two groups of medical risk: one that has excellent outcome with open repair and derives no early mortality benefit from EVAR, and another that has significant mortality with open repair and derives important benefit with EVAR.

Sealing of type III endoleaks with ethylene vinyl alcohol copolymer in a canine model

PURPOSE

To test ethylene vinyl alcohol copolymer (EVOH) as a sealing agent for persistent abdominal aortic aneurysm (AAA) endograft leaks.

MATERIALS AND METHODS

Twelve dogs underwent creation of AAAs with a Palmaz P4014 stent. A 10-mm x 5-cm Wallgraft endoprosthesis with a 4-mm-diameter hole cut into its side was deployed within the AAA. One week later, computed tomography (CT) and angiography were performed and the aneurysm sac was catheterized through the 4-mm hole. Then, EVOH was injected into the sac and lumbar arteries. Four weeks thereafter, all surviving animals underwent repeat CT scanning and angiography and were then euthanized. The AAA underwent gross and microscopic study.

RESULTS

Three dogs died from aortic rupture within 24 hours of AAA creation and the remaining nine dogs survived to receive EVOH. All nine dogs had persistent flow into the sac and lumbar arteries at the time of EVOH delivery. Seven dogs survived to the end of the experiment, and all aneurysm sacs and lumbar arteries remained occluded on angiography and CT. Histologic examination revealed EVOH and thrombus admixed, with thrombus in varying stages of organization filling the aneurysm sac and lumbar arteries.

CONCLUSIONS

Embolization of type III endoleaks with EVOH proved to be feasible in a canine model. Further work is warranted to determine its therapeutic utility.

Contrast ultrasound imaging: the best method to detect type II endoleak during endovascular aneurysm repair follow-up☆

OBJECTIVES

Type II endoleak is the most common complication after endovascular aneurysm repair and require close surveillance. Hence, the need to validate new techniques as alternative to helical CT-scan, the reference standard. The aim of this study is to evaluate the efficacy of Cadence Contrast Pulse Sequencing ultrasound technique with second generation contrast agents in detecting endoleaks, and to compare the results with data obtained from CTA.

METHODS

30 patients with endovascular stent grafts, during their regular follow-up consisting in serial CT and ultrasound exams performed at discharge, at one and six months and at one year thereafter, previous informed consent, were enrolled in a prospectic double blind study design in order to compare triphasic helical CT-scan to another adjunctive ultrasound investigation (Cadence CPS technique with Sono Vue). No more than 15 days occurred between the two examinations. In the study were evaluated only data obtained from the comparison of the two concomitant investigations, independently from the follow-up. Variables analysed were changes in the maximum diameter of the aneurysmal sac, presence and type of endoleak, if detected. In the case of disagreement between the two diagnostic tools angiography was performed.

RESULTS

One patient dropped out because of violation of the study protocol (a stroke occurred in the time interval between the two investigations). Both exams visualised patency and proper graft placement in all the remaining patients. Aneurysmal diameters with both investigations overlapped (r(s):0.98). In 21 patients no endoleak was detected with a significant aneurysmal sac shrinkage (P<0.001). In seven patients both methods confirmed presence of endoleak. Ultrasonography detected all type of endoleaks, while CT-scan was uncertain in one. Moreover, in one patient CT-angiography showed an increased aneurysmal diameter without other evidence, while a contrast ultrasound investigation disclosed a type II low-flow endoleak, confirmed by angiography.

CONCLUSIONS

The Cadence Contrast Pulse Sequencing with echo contrast agent is an ultrasound technique that substantially improves the ultrasound diagnostic reliability.

The Current Status of AAA Stent Grafting

It is now 16 years since the endovascular treatment of abdominal aortic aneurysm (AAA) was first described. It is probably true to say that, with current device technology, > 50% of all patients with an infrarenal aneurysm can be treated with an endograft. Endografting has become an important tool in the treatment of AAA. There are many reasons for this success. Rapid technical development followed the initial "homemade" devices, allowing easy accurate insertion. In early cohort series it was always the case that the operative mortality of endografting in AAA was lower than surgical treatment. In addition, postoperative management was easier and hospital stay was shorter after an endograft. No evidence indicated that quality of life improved after the perioperative period, however, and it was unclear whether the reduction in intensive hospital care requirement justified the considerable extra costs for an endovascular device. Despite these shortcomings, early widespread public awareness pushed endograft treatment forward. Patients started to ask for this new treatment option. But long-term outcome data then, and to some extent today, are still lacking.

Patient fitness and survival after abdominal aortic aneurysm repair in patients from the UK EVAR trials

Background

The aim was to use a validated fitness score to determine whether fitter patients with a large abdominal aortic aneurysm (AAA) benefited from having open rather than endovascular repair.

Methods

The Customized Probability Index (CPI) was applied to patients in the Endovascular Aneurysm Repair (EVAR) I and II trials. Interaction tests between CPI and randomized group assessed the effect of fitness and type of AAA repair on elective 30-day mortality and 4-year survival.

Results

The mean(s.d.) CPI scores were 3·6(9·3) for 1252 EVAR I patients and 10·0(11·3) for 404 EVAR II patients (range − 25 to + 43) (P &lt; 0·001). The fitness of EVAR I patients was classified as good (579 patients, mean CPI − 4·2), moderate (331 patients, mean CPI 5·7) or poor (338 patients, mean CPI 15·1). Only in the good fitness group did 30-day mortality convincingly favour endovascular repair (odds ratio 0·24, P = 0·030), but overall the test of interaction was not significant (P = 0·363). For 4-year all-cause and aneurysm-related mortality, there was no benefit for either treatment across all fitness scores (P = 0·281 and P = 0·371 respectively).

Conclusion

The benefit of endovascular repair was most convincing in the fittest patients. There was no evidence that the fittest patients benefited more from open surgery.

Final 12-year follow-up of Surgery versus Surveillance in the UK Small Aneurysm Trial

Background

The aim was to determine whether early open surgical repair would benefit patients with small abdominal aortic aneurysm compared with surveillance on long-term follow-up.

Methods

The 1090 patients who were enrolled into the UK Small Aneurysm Trial between 1991 and 1995 were followed up for aneurysm repair and mortality until November 2005.

Results

By November 2005, 714 patients (65·5 per cent) had died, 929 (85·2 per cent) had undergone aneurysm repair, 150 (13·8 per cent) had died without aneurysm repair and 11 (1·0 per cent) remained alive without aneurysm repair. After 12 years, mortality in the surgery and surveillance groups was 63·9 and 67·3 per cent respectively, unadjusted hazard ratio 0·90 (P = 0·139). Three-quarters of the surveillance group eventually had aneurysm repair, with a 30-day elective mortality of 6·3 per cent (versus 5·0 per cent in the early surgery group, P = 0·366). Estimates suggested that the cost of treatment was 17 per cent higher in the early surgery group, with a mean difference of £1326. The death rate in these patients was about twice that in the population matched for age and sex.

Conclusion

There was no long-term survival benefit of early elective open repair of small abdominal aortic aneurysms. Even after successful aneurysm repair, the mortality among these patients was higher than in the general population.

Myocardial Damage in High-risk Patients Undergoing Elective Endovascular or Open Infrarenal Abdominal Aortic Aneurysm Repair

OBJECTIVE

Dobutamine stress echocardiography (DSE) provides an objective assessment of the presence and extent of coronary artery disease. Therefore we compared cardiac outcome in patients at high-cardiac risk undergoing open or endovascular repair of infrarenal AAA using preoperative DSE results.

METHODS

Consecutive patients with >or=3 cardiac risk factors (age >70 years, angina pectoris, myocardial infarction, heart failure, stroke, renal failure, and diabetes mellitus) undergoing infrarenal AAA repair were reviewed retrospectively. All underwent cardiac stress testing using DSE. Postoperatively data on troponin release and ECG were collected on day 1, 3, 7, before discharge, and on day 30. The main outcome measures were perioperative myocardial damage and myocardial infarction or cardiovascular death.

RESULTS

All 77 patients (39 endovascular, 38 open) had a history of cardiac disease. The number and type of cardiac risk factors were similar in both groups. Also DSE results were similar: 55 vs 56%, 24 vs 28%, and 21 vs 18% had no, limited, or extensive stress induced myocardial ischemia respectively. The incidence of perioperative myocardial damage (47% vs 13%, p=0.001) and the combination of myocardial infarction or cardiovascular death (13% vs 0%, p=0.02) was significantly lower in patients receiving endovascular repair.

CONCLUSION

In patients with similar high cardiac risk, endovascular repair of infrarenal aortic aneurysms is associated with a reduced incidence of perioperative myocardial damage.

Clinical Trial Results of a Modified Gore Excluder Endograft: Comparison with Open Repair and Original Device Design

A multicenter phase II clinical trial of aneurysm treatment was performed with the modified Gore Excluder bifurcated endoprosthesis (m-EBE, n = 193) and compared with previously reported results from the same group of the original unmodified device (EBE, n = 253) or standard open aneurysm exclusion (control, n = 99). Graft modifications were primarily related to the proximal attachment site and included an increase in the length of the external expanded polytetrafluoroethylene and modifications of the anchor configuration. Preprocedural characteristics, periprocedural clinical events, and postprocedural clinical and radiographic follow-up at 1, 6, 12, and 24 months were analyzed with univariate and multivariate statistics. Device placement was successful in all cases, and there were no aneurysm ruptures in any group. Survival to 2 years was similar in all groups. Early major adverse events with the m-EBE were similar to those with the EBE (14.5% vs. 14%, P = 0.9) and markedly reduced compared to the control group (60.6%, P < 0.0001). After 30 days, there was no significant difference in the occurrence of major adverse events between endoluminal treatment and open controls. The rates of documented endoleak and increased aneurysm size at each follow-up interval were not significantly different between the two endoluminal devices. However, there was a trend toward fewer reinterventions from 14 to 28 months with the m-EBE (2% vs. 6% with the EBE, P < 0.06). There were also significantly fewer major adverse events associated with the m-EBE compared to the EBE during 14- to 28-month follow-up (15.6% vs. 24.9%, P = 0.037), in part due to the difference in reinterventions. The safety and efficacy of the m-EBE are statistically similar to the original device, although there was a reduction in major late adverse events between the two iterations of the endograft. This difference appears to be related to increased operator experience and changing treatment algorithms. Compared with open aneurysm repair, endoluminal repair with the m-EBE offers advantages in the reduction of early major adverse events while maintaining similar survival and rupture-free outcomes in the intermediate term.

Surgery Insight: advances in endovascular repair of abdominal aortic aneurysms

Despite improvements in diagnostic and therapeutic methods and an increased awareness of their clinical significance, abdominal aortic aneurysms (AAAs) continue to be a major source of morbidity and mortality. Endovascular repair of AAAs, initially described in 1990, offers a less-invasive alternative to conventional open repair. The technology and devices used for endovascular repair of AAAs have progressed rapidly and the approach has proven to be safe and effective in short to midterm investigations. Furthermore, several large trials have demonstrated that elective endovascular repair is associated with lower perioperative morbidity and mortality than open repair. The long-term benefits of endovascular repair relative to open repair, however, continue to be studied. In addition to elective repair, the use of endovascular repair for ruptured AAAs has been increasing, and has been shown to be associated with reduced perioperative morbidity and mortality. Advances in endovascular repair of AAAs, including the development of branched and fenestrated grafts and the use of implantable devices to measure aneurysm-sac pressures following stent-graft deployment, have further broadened the application of the technique and have enhanced postoperative monitoring. Despite these advances, endovascular repair of AAAs remains a relatively novel technique, and further long-term data need to be collected.

Endovascular abdominal aortic aneurysm repair

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

Epidemiological study of the relationship between volume and outcome after abdominal aortic aneurysm surgery in the UK from 2000 to 2005

Background

The aim was to assess the relationship between hospital volume and outcome after abdominal aortic aneurysm (AAA) surgery in the UK.

Methods

Hospital Episode Statistics (2000–2005) were classified as elective, urgent or ruptured AAA repair. Analysis was by modelling of mortality rate, complication rate and length of hospital stay with regard to the annual operative volume, after risk adjustment.

Results

There were 112 545 diagnoses, or repairs, of AAAs, of which 26 822 were infrarenal aneurysms. The mean mortality rate was 7·4, 23·6 and 41·8 per cent for elective, urgent and ruptured AAA repair respectively. Elective AAA repair undertaken at high-volume hospitals showed volume-related improvements in mortality (P &lt; 0·001). Patients were discharged from hospital earlier (P &lt; 0·001). The critical volume threshold was 32 elective AAA repairs per year. For urgent repair, patients at high-volume hospitals had a reduced mortality rate (P = 0·017) with an increased length of stay (P = 0·041). There was no relationship between volume and outcome for ruptured AAA repairs.

Conclusion

Increased annual volumes were associated with significant reductions in mortality for elective and urgent AAA repair, but not for repair of ruptured AAAs.

Results of streamlined regional ambulance transport and subsequent treatment of acute abdominal aortic aneurysms

OBJECTIVE

To describe the triage of patients operated for non-ruptured and ruptured abdominal aortic aneurysms (AAAs) before the endovascular era.

DESIGN

Retrospective single-centre cohort study.

METHODS

All patients treated for an acute AAA between 1998 and 2001 and admitted to our hospital were evaluated in the emergency department for urgent AAA surgery. All time intervals, from the telephone call from the patient to the ambulance department, to the arrival of the patient in the operating theatre, were analysed. Intraoperative, hospital and 1-year survival were determined.

RESULTS

160 patients with an acute AAA were transported to our hospital. Mean (SD) age was 71 (8) years, and 138 (86%) were men. 34 (21%) of these patients had symptomatic, non-ruptured AAA (sAAA) and 126 patients had ruptured AAA (rAAA). All patients with sAAA and 98% of patients with rAAA were operated upon. For the patients with rAAA, median time from telephone call to arrival at the hospital was 43 min (interquartile range 33-53 min) and median time from arrival at the hospital to arrival at the operating room was 25 min (interquartile range 11-50 min). Intraoperative mortality was 0% for sAAA and 11% for rAAA (p = 0.042), and hospital mortality was 12% and 33%, respectively (p = 0.014).

CONCLUSIONS

A multidisciplinary unified strategy resulted in a rapid throughput of patients with acute AAA. Rapid transport, diagnosis and surgery resulted in favourable hospital mortality. Despite the fact that nearly all the patients were operated upon, survival was favourable compared with published data.

Intraobserver and interobserver variability of 64-row computed tomography abdominal aortic aneurysm neck measurements

BACKGROUND

Integrity of the abdominal aortic aneurysm (AAA) neck is crucial for the long-term success of endovascular AAA repair (EVAR). However, suitable tools for reliable assessment of changes in small aortic volumes are lacking. The purpose of this study was to assess the intraobserver and interobserver variability of software-enhanced 64-row computed tomographic angiography (CTA) AAA neck volume measurements in patients after EVAR.

METHODS

A total of 25 consecutive patients successfully treated by EVAR underwent 64-row follow-up CTA in 1.5-mm collimation. Manual CTA measurements were performed twice by three blinded and independent readers in random order with at least a 4-week interval between readings. Maximum and minimum transverse aortic neck diameters were measured twice on two different levels within the proximal neck. Volumetry of the proximal aortic neck was performed by using dedicated software. Variability was calculated as 1.96 SD of the mean arithmetic difference according to Bland and Altman. Two-sided and paired t tests were used to compare measurements. P values <.05 were considered to indicate statistical significance.

RESULTS

Intraobserver agreement was excellent for dedicated aneurysmal neck volumetry, with mean differences of less than 1 mL (P > .05), whereas it was poor for transverse aortic neck diameter measurements (P < .05). However, interobserver variability was statistically significant for both neck volumetry (P < .005) and neck diameter measurements (P < .015).

CONCLUSIONS

The reliability of dedicated AAA neck volumetry by using 64-row CTA is excellent for serial measurements by individual readers, but not between different readers. Therefore, studies should be performed with aortic neck volumetry by a single experienced reader.

Large infra-renal abdominal aortic aneurysms: endovascular vs. open repair--single centre experience

Endovascular aneurysm repair (EVAR) has become an established alternative to open repair (OR). We present a consecutive series of 486 elective patients with large infra-renal aortic abdominal aneurysm, comparing OR with EVAR. Prospective data collected during an 8-year period from January 1997 to October 2005 was reviewed. Statistical analysis performed using SPSS data editor with chi(2) tests and Mann-Whitney U-tests. There were 486 patients with 329 OR (293 males, 36 females) with median age of 72 years with median diameter 6.3 cm and 157 EVAR (148 males, 9 females) with median age 75 years with median diameter 6.1 cm. Mortality was 13 (4%) for OR and 5 (3.2%) for EVAR (three of whom were in the UK EVAR 2 trial). Blood loss was significantly less for EVAR 500 ml vs. 1500 ml for OR. Sixty-five (19.8%) patients with OR had significantly more peri-operative complications compared with 14 (8.9%) with EVAR. The length of stay in hospital was significantly less for EVAR. This non-randomised study shows that although EVAR does not have a statistically significantly lower mortality, it does have statistically significantly lower complication rates compared with OR. EVAR can be achieved with good primary success, but long-term follow-up is essential to assess durability.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The outcome of endovascular repair of small abdominal aortic aneurysms

OBJECTIVE

To assess the outcome of endovascular repair (EVAR) of small abdominal aortic aneurysms (AAA, <or=5.5 mm maximum diameter) in Australia.

SUMMARY BACKGROUND DATA

Randomized trials have suggested that small AAAs should not be treated by open surgery. EVAR is associated with less perioperative mortality than open surgery for large AAAs. We assessed the outcome of EVAR of small AAAs as part of a national audit.

METHODS

ASERNIP-S carried out a prospective audit of EVAR performed between November 1999 and May 2001 in Australia. A total of 478 of the 961 patients entered underwent treatment of a small AAA. Data were collected regarding preoperative characteristics, procedural outcome, and intermediate success. Median follow-up was 3.2 years. Data were analyzed using Kaplan-Meier and Cox proportional hazard analyses.

RESULTS

The 30-day mortality and technical success rates were 1.1% and 98%, respectively. Postoperative complications occurred in 29%. Survival was 84% and 52% at 3 and 5 years, respectively. Primary, assisted primary, and secondary clinical success rates were 72%, 79%, and 82%, respectively, at 3 years. Reintervention rate was 11% at 3 years; however, 15% of patients continued to have significant aortic sac enlargement. Survival was reduced in patients considered unfit for general anesthesia (odds ratio = 2.6; 95% confidence interval, 1.4-4.8, P = 0.002) or those who had elevated preoperative serum creatinine (odds ratio = 2.0; 95% confidence interval, 1.3-3.0, P = 0.001).

CONCLUSIONS

EVAR can be carried with good perioperative outcome in patients with small AAA; however, intermediate success is hampered by the need for reintervention and continued aortic sac enlargement. At present, widespread treatment of small AAAs by EVAR would appear inappropriate.

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

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

Influence of Severe Infrarenal Aortic Neck Angulation on Complications at the Proximal Neck Following Endovascular AAA Repair: A EUROSTAR Study

PURPOSE

To examine the influence of severe infrarenal neck angulation (SNA) on complications after endovascular repair of abdominal aortic aneurysm (AAA).

METHODS

From October 1996 to January 2006, 5183 patients who underwent endovascular aneurysm repair using a Talent, Zenith, or Excluder stent-graft were enrolled into the EUROSTAR registry. Incidence of proximal type I endoleak, stent-graft migration, proximal neck dilatation, aneurysm rupture, secondary interventions, and all-cause and aneurysm-related mortality were compared between patients with and without severe infrarenal neck angulation (>60 degrees angle between the infrarenal aortic neck and the longitudinal axis of the aneurysm).

RESULTS

In the short term (before discharge), proximal type I endoleak (OR 2.32, 95% CI 1.60 to 3.37, p<0.0001) and stent-graft migration (OR 2.17, 95% CI 1.20 to 3.91, p=0.0105) were observed more frequently in patients with SNA. Over the long term, higher incidences of proximal neck dilatation > or =4 mm (HR 1.26, 95% CI 1.11 to 1.43, p=0.0004), proximal type I endoleak (HR 1.80, 95% CI 1.25 to 2.58, p=0.0016), and need for secondary interventions (HR 1.29, 95% CI 1.00 to 1.67, p=0.0488) were seen in patients with SNA. All-cause mortality, aneurysm-related mortality, and rupture of the aneurysm were similar in patients with and without severe neck angulation. In the subgroup of patients with an Excluder endograft, proximal endoleak at the completion angiogram (OR 4.49, 95% CI 1.31 to 15.32, p=0.0166) and long-term proximal neck dilatation (HR 1.67, 95% CI 1.20 to 2.33, p=0.0026) were more frequently observed in patients with SNA. In the Zenith subgroup, proximal endoleak at the completion angiogram (OR 2.62, 95% CI 1.49 to 4.63, p=0.0009) and proximal stent-graft migration before discharge (OR 2.34, 95% CI 1.06 to 5.19, p=0.0353) were more common in patients with SNA. In the Talent subgroup, long-term proximal endoleak (HR 2.09, 95% CI 1.27 to 3.44, p=0.0036), proximal neck dilatation (HR 1.29, 95% CI 1.05 to 1.60, p=0.0168), and secondary interventions (HR 1.54, 95% CI 1.05 to 2.24, p=0.0259) were more frequently observed in patients with SNA.

CONCLUSION

Severe infrarenal aortic neck angulation was clearly associated with proximal type I endoleak, while the relationship with stent-graft migration was not clear. Excluder, Zenith, and Talent stent-grafts perform well in patients with severe neck angulation, with only a few differences among devices.

Elective treatment of abdominal aortic aneurysm with endovascular or open repair: The first decade

OBJECTIVES

The development of endovascular aneurysm repair (EVAR) as an alternative to open repair of abdominal aortic aneurysms (AAA) has led to an increasing number of patients being treated by this less-invasive technique. It was anticipated that EVAR would reduce the operative mortality and morbidity compared with open repair. This study examined the initial 10-year experience in one center when both techniques were available to determine if there were advantages to one technique or the other, putting the results into the perspective of routine clinical care of patients with infrarenal AAA.

METHODS

From June 1996 to May 2005, 677 patients underwent elective repair of their infrarenal AAA, of which 417 were treated with open repair and 260 by EVAR. Demographic and aneurysm-specific data, comorbidities, operative morbidity, mortality, and late outcome were analyzed.

RESULTS

Open repair patients were 2 years younger (71 vs 74 years, P < .001), had larger aneurysms (6.01 +/- 1.38 cm vs 5.45 +/- 0.99 cm, P < .001), greater familial predisposition, a higher incidence of current smokers, and a higher incidence of chronic obstructive pulmonary disease than the EVAR group. There were no differences in renal function, hypertension, coronary artery disease, or heart failure between the two groups. Overall operative mortality was 3.1%; operative mortality per group was 3.5% for open and 2.7% for EVAR (P = .627). Procedure-related outcomes showed significant differences in operative blood loss and length of hospital stay in favor of EVAR, and 95% of the EVAR patients were discharged home vs 83% in the open repair group (P < .001). A Kaplan-Meier log-rank analysis showed no difference in early or long-term survival between open repair and EVAR (P = .20), but did show a difference in mid-term (3-year) survival favoring open repair (P < .002). Survival analysis by age (<70 and > or =70 years) showed no difference between treatment groups.

CONCLUSIONS

Open repair and EVAR are both performed safely in patients treated for elective infrarenal AAA. EVAR has the perioperative advantages of reduced blood loss, reduced length of intensive care unit and hospital stay, and increased number of patients discharged to home. The mid-term survival advantage of open repair has been observed in other reports and deserves further study.

Treatment of Infrarenal Abdominal Aortic Aneurysms With Oversized (36-mm) Zenith Endografts

PURPOSE

To evaluate the outcome of treating infrarenal abdominal aortic aneurysms with unfavorable necks using the 36-mm Zenith endograft.

METHODS

The indication for use of the 36-mm endograft for infrarenal aortic aneurysm was a minimum 20-mm-long sealing zone and a diameter >28 mm at any point but <34 mm, varying more than 3 mm in contour. A series of 67 patients (64 men; mean age 76.2 years, range 59.5 to 88.3) who had been treated with the 36-mm endografts between June 1999 and February 2004 were assessed for medium-term outcomes. The patients were identified from the device planning records. Follow-up was carried out using chart review and direct patient contact. The indication for use of the endograft was checked with the aneurysm neck profile from the original planning diagrams. Cause of death was ascertained from the treating clinician, the medical record, or the State Death Registry. Outcome endpoints were proximal type I and type III endoleaks, migration, sac size change, and death.

RESULTS

The mean diameter of the sealing zone was 31.9+/-1.6 mm within the 20-mm segment from the lowest renal artery. Stent-graft delivery was achieved in all 67 patients. Two (3%) patients died within 30 days from non-graft-related cardiorespiratory causes. Proximal type I endoleaks were identified in 3 (4.5%) patients: 2 during deployment and another at 9 days. The mean follow-up period for the 65 patients who survived 30 days was 26.9+/-12.6 months (range 2-66). Migration occurred in 1 patient with development of a type III endoleak and sac reperfusion due to separation of the graft body from the bare anchor stent owing to suture breakage. Forty-seven patients were alive at the last review. The aneurysm sac had contracted or was unchanged in 45 (96%) cases. Minor enlargements of the sac were observed in 2 patients. The re-intervention rate was 16.4% (11 patients). There was 1 conversion to open repair to treat perigraft sepsis. The aneurysm- and procedure-related mortality was 4.5%; no patient experienced rupture. All-cause mortality was 29.9% (20/67).

CONCLUSION

Large caliber endografts such as the Zenith 36-mm are an alternative option to open surgery or fenestrated endografting for some infrarenal aneurysms.

Initial Observations of Endovascular Aneurysm Repair Using Dyna-CT

PURPOSE

To examine the feasibility of a new technology that provides images resembling computed tomographic (CT) slices on the operating table during elective endovascular abdominal aortic aneurysm (AAA) repair (EVAR).

TECHNIQUE

Commercially available Dyna-CT equipment was used in conjunction with Voxar 3D software for image reconstruction. During the preliminary evaluation of 9 patients (7 men; median age 73 years, range 67-84) with non-ruptured AAA undergoing elective EVAR with the Zenith Trifab stent-graft under regional anesthesia, the equipment functioned sufficiently well to produce the planned image dataset in 8 of 9 patients. Rotation failed in 1 overweight individual due to a short distance between the patient's abdomen and the C-arm. In 7 of 8 patients, the radiologist was able to measure the diameter of the aneurysm, and it was possible to visualize the entire length of the treated aorta and the iliac arteries in all cases. The proximal aortic neck, including the stent-graft, was visualized in 7 cases. No endoleak or other complications was detected, which was confirmed on the pre-discharge CT scans. The time interval from the rotation of the C-arm until the appearance on the monitor of the first automatically generated 3D images was 7 minutes, which has subsequently been reduced to approximately 2 minutes.

CONCLUSION

Our preliminary experience with Dyna-CT is promising, but further research is necessary to define the place of this imaging modality in EVAR.

Performance of endovascular aortic aneurysm repair in high-risk patients: Results from the Veterans Affairs National Surgical Quality Improvement Program

OBJECTIVE

Recent results after endovascular abdominal aortic aneurysm repair (EVAR) have brought into question its value in patients deemed at high-risk for surgical intervention. The Department of Veteran Affairs (VA) National Surgical Quality Improvement Program (NSQIP) is the largest prospectively collected and validated United States surgical database representing current clinical practice. The purpose of our study was to evaluate outcomes after elective EVAR performed in high-risk veterans.

METHODS

Using NSQIP data from 123 participating VA hospitals, we retrospectively evaluated patients who underwent elective aneurysm repair from May 2001 to December 2004. High-risk criteria were used to identify a cohort for analysis (EVAR, n = 788; open, n = 1580). High-risk criteria analyzed included age > or =60 years, American Society of Anesthesiology (ASA) classification 3 or 4, and the comorbidity variables of history of cardiac, respiratory, or hepatic disease, cardiac revascularization, renal insufficiency, and low serum albumin level. Our primary end points were 30-day and 1-year all-cause mortality, and we evaluated a secondary end point of perioperative complications. Statistical analysis included univariate analysis and multivariate modeling.

RESULTS

Veterans who were classified as high-risk underwent elective EVAR with significantly lower 30-day (3.4% vs 5.2%, P = .047) and 1-year all-cause mortality (9.5% vs 12.4%, P = .038) than patients having open repair. EVAR was associated with a decrease in 30-day postoperative mortality (adjusted odds ratio [OR], 0.65; 95% confidence interval [CI], 0.42 to 1.03; P = .067) as well as 1-year mortality (adjusted OR, 0.68; 95% CI, 0.51 to 0.91; P = .0094) despite the presence of severe comorbid conditions. The risk of perioperative complications was significantly lower after EVAR (16.2% vs 31.0%; P < .0001; adjusted OR, 0.41; 95% CI, 0.33 to 0.52; P < .0001). A subset analysis of higher-risk patients (ASA 4 and the above comorbidity variables) still demonstrated an acceptable 30-day mortality rate.

CONCLUSION

In veterans deemed high-risk for surgical therapy, outcomes after elective EVAR are excellent, and the procedure is relatively safe in this special patient population. Our retrospective data demonstrate that patients with considerable medical comorbidities and infrarenal abdominal aortic aneurysms benefit from and should be considered for primary EVAR.

Nitrogen-rich coatings for promoting healing around stent-grafts after endovascular aneurysm repair

Complications following endovascular aneurysm repair (EVAR) are related to deficient healing around the stent-graft (SG). New generations of SG with surface properties that foster vascular repair could overcome this limitation. Our goal was to evaluate the potential of a new nitrogen-rich plasma-polymerised biomaterial, designated PPE:N, as an external coating for polyethylene terephtalate (PET)- or polytetrafluoro-ethylene (PTFE)-based SGs, to promote healing around the implant. Thin PPE:N coatings were deposited on PET and PTFE films. Then, adhesion, growth, migration and resistance to apoptosis of vascular smooth muscle cells (VSMCs) and fibroblasts, as well as myofibroblast differentiation, were assessed in vitro. In another experimental group, chondroitin sulphate (CS), a newly described mediator of vascular repair, was added to normal culture medium, to search for possible additional benefit. PPE:N-coatings, especially on PET, increased and accelerated cell adhesion and growth, compared with control PET and with standard polystyrene culture plates (PCP). PPE:N was also found to increase the resistance to apoptosis in VSMC, an important finding as aneurysms are characterised by VMSC depletion caused by a pro-apoptotic phenotype. Addition of CS in solution further increased migration and resistance to apoptosis. In conclusion, PPE:N-coating and/or CS could promote vascular repair around SGs following EVAR.