Mid-term results of endovascular versus open repair for abdominal aortic aneurysm in patients anatomically suitable for endovascular repair

Meta-analysis of long-term survival after elective endovascular or open repair of abdominal aortic aneurysm

BACKGROUND

Endovascular aneurysm repair (EVAR) has become the preferred strategy for elective repair of abdominal aortic aneurysm (AAA) for many patients. However, the superiority of the endovascular procedure has recently been challenged by reports of impaired long-term survival in patients who underwent EVAR. A systematic review of long-term survival following AAA repair was therefore undertaken.

METHODS

A systematic review was performed according to PRISMA guidelines. Articles reporting short- and/or long-term mortality of EVAR and open surgical repair (OSR) of AAA were identified. Pooled overall survival estimates (hazard ratios (HRs) with corresponding 95 per cent c.i. for EVAR versus OSR) were calculated using a random-effects model. Possible confounding owing to age differences between patients receiving EVAR or OSR was addressed by estimating relative survival.

RESULTS

Some 53 studies were identified. The 30-day mortality rate was lower for EVAR compared with OSR: 1·16 (95 per cent c.i. 0·92 to 1·39) versus 3·27 (2·71 to 3·83) per cent. Long-term survival rates were similar for EVAR versus OSR (HRs 1·01, 1·00 and 0·98 for 3, 5 and 10 years respectively; P = 0·721, P = 0·912 and P = 0·777). Correction of age inequality by means of relative survival analysis showed equal long-term survival: 0·94, 0·91 and 0·76 at 3, 5 and 10 years for EVAR, and 0·96, 0·91 and 0·76 respectively for OSR.

CONCLUSION

Long-term overall survival rates were similar for EVAR and OSR. Available data do not allow extension beyond the 10-year survival window or analysis of specific subgroups.

Clinical Impact of Chronic Renal Insufficiency on Endovascular Aneurysm Repair

Endovascular aneurysm repair of abdominal aortic aneurysms has become a viable alternative to open repair. A significant proportion of this patient population has chronic renal insufficiency. The surgical outcomes associated with endovascular repair in 342 patients, with and without chronic renal insufficiency, are reported. Perioperative mortality, length of admission, length of intensive care unit admission, and rates of acute renal failure, congestive heart failure, myocardial infarction, conversion to open surgery, progression to hemodialysis, and incidence of endoleaks were retrospectively reviewed and analyzed. Endovascular repair demonstrated higher rates of acute renal failure, longer length of stay, and longer intensive care unit admissions in patients with chronic renal insufficiency. Patients with severe renal dysfunction demonstrated markedly elevated mortality and morbidity. These results indicate that chronic renal insufficiency is not an absolute contraindication to endovascular repair in patients with moderate renal dysfunction, but patients with severe renal dysfunction perform poorly after aortic reconstruction.

Frequency, Predictive Factors, and Consequences of Stent-Graft Kink following Endovascular AAA Repair

Purpose:

To determine from the EUROSTAR registry the incidence of stent-graft kink, predictive factors for kinking, and the consequences of this complication on graft patency and aneurysm exclusion.

Methods:

From January 1994 to June 2002, 4613 patients who underwent endovascular aneurysm repair were registered in the EUROSTAR registry. Presence of kink was determined according to the information available on the follow-up Case Record Form. The population was divided into those with and without stent-graft kink. Patient characteristics, morphological aneurysm features, team experience, type of device, period of implantation, and outcome were compared between the groups by univariate analysis. Significant factors were subsequently submitted to a multivariate Cox proportional hazard analysis.

Results:

One hundred seventy (3.7%) patients were reported as having a kink of the stent-graft during a mean follow-up of 21 months (range 1–72). Gender, neck angulation, team experience, period of implantation, ASA classification, and device type were independent predictors of kink. The presence of a kink was significantly associated with type I endoleaks (proximal and distal), type III endoleaks (midgraft), graft stenosis, graft limb thrombosis, graft migration, and conversion to open repair. No relationship was found between a decrease in the aneurysm diameter and the occurrence of stent-graft kink.

Conclusions:

Kinks of stent-grafts were infrequent events in the intermediate term. Patients most at risk were women with angulated aortic necks treated by a minimally experienced team. Kinks are potentially damaging events because they may lead to delayed device-related endoleaks, graft stenosis, thrombosis, and conversion to open repair. They appear more closely associated to graft migration than to aneurysm diameter reduction.

Mini-invasive aortic surgery: personal experience

OBJECTIVE

In this study, we retrospectively evaluated our experience in minilaparotomy (MINI) and compared the results with conventional open repair (OPEN).

METHODS

From January 2005 to December 2012, we surgically treated 234 consecutive patients with elective infrarenal abdominal aortic aneurysms, 195 men and 39 women, with a mean age of 74 years. Inclusion criteria for MINI were not ruptured abdominal aortic aneurysm, increased surgical risk, anatomical limits for endovascular repair, no previous surgical invasion of the abdominal cavity, and no requirement for concomitant abdominal surgical invasion. Surgical treatment was OPEN in 113 patients (48.3%) and MINI through an 8- to 14-cm incision in 121 patients (51.7%). Epidural anesthesia has been added in 26.5% and in 19.3% of the MINI and OPEN patients, respectively. Mortality, complications, aortic clamping time, operative time, need for postoperative morphine therapy, time to solid diet, and length of hospital stay were registered.

RESULTS

The MINI has been performed in all patients selected, with 72 aortoaortic grafts and 49 aortobisiliac grafts. Early mortality was 1.6% versus 3.5% (P > 0.5); 1-, 3-, and 5-year mortality were 7% versus 9%, 19% versus 22%, and 29% versus 34% (P > 0.5); complications were 12.2% versus 26.6% (P > 0.05); mean (SD) clamping time was 48 (12) versus 44 (14) minutes (P > 0.5); mean (SD) operative time was 218.72 (41.95) versus 191.44 (21.73) minutes (P > 0.025); mean (SD) estimated intraoperative blood loss was 425.64 (85.95) versus 385.30 (72.41) mL (P > 0.1); mean (SD) morphine consumption in the group given epidural and the group not given epidural was 0 (2) and 2 (2) mg intravenously (IV) versus 2 (4) (P < 0.5) and 4 (3) mg IV (P > 0.1); mean (SD) ambulation was 2.1 (0.6) versus 4.1 (2.7) (P < 0.5); mean (SD) time to solid diet was 2.1 (0.4) versus 3.5 (1.6) (P < 0.5); and mean (SD) length of hospital stay was 4.9 (1.64) versus 7.35 (1.95) days (P > 0.05), in the MINI and OPEN groups, respectively. Postoperative hernia at 3 years was 18% versus 23% in the MINI and OPEN groups (P < 0.5), respectively.

CONCLUSIONS

The MINI gives the patients a significantly shorter period of recovery with the quality and safety of the OPEN. This experience suggested extending the indication to all surgical candidates without local limitations.

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

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

The impact of using informative priors in a Bayesian cost-effectiveness analysis: an application of endovascular versus open surgical repair for abdominal aortic aneurysms in high-risk patients

BACKGROUND

Bayesian methods have been proposed as a way of synthesizing all available evidence to inform decision making. However, few practical applications of the use of Bayesian methods for combining patient-level data (i.e., trial) with additional evidence (e.g., literature) exist in the cost-effectiveness literature. The objective of this study was to compare a Bayesian cost-effectiveness analysis using informative priors to a standard non-Bayesian nonparametric method to assess the impact of incorporating additional information into a cost-effectiveness analysis.

METHODS

Patient-level data from a previously published nonrandomized study were analyzed using traditional nonparametric bootstrap techniques and bivariate normal Bayesian models with vague and informative priors. Two different types of informative priors were considered to reflect different valuations of the additional evidence relative to the patient-level data (i.e., "face value" and "skeptical"). The impact of using different distributions and valuations was assessed in a sensitivity analysis. Models were compared in terms of incremental net monetary benefit (INMB) and cost-effectiveness acceptability frontiers (CEAFs).

RESULTS

The bootstrapping and Bayesian analyses using vague priors provided similar results. The most pronounced impact of incorporating the informative priors was the increase in estimated life years in the control arm relative to what was observed in the patient-level data alone. Consequently, the incremental difference in life years originally observed in the patient-level data was reduced, and the INMB and CEAF changed accordingly.

CONCLUSIONS

The results of this study demonstrate the potential impact and importance of incorporating additional information into an analysis of patient-level data, suggesting this could alter decisions as to whether a treatment should be adopted and whether more information should be acquired.

Fatores envolvidos na migração das endopróteses em pacientes submetidos ao tratamento endovascular do aneurisma da aorta abdominal

A migração da endoprótese é complicação do tratamento endovascular definida como deslocamento da ancoragem inicial. Para avaliação da migração, verifica-se a posição da endoprótese em relação a determinada região anatômica. Considerando o aneurisma da aorta abdominal infrarrenal, a área proximal de referência consiste na origem da artéria renal mais baixa e, na região distal, situa-se nas artérias ilíacas internas. Os pacientes deverão ser monitorizados por longos períodos, a fim de serem identificadas migrações, visto que estas ocorrem normalmente após 2 anos de implante. Para evitar migrações, forças mecânicas que propiciam fixação, determinadas por características dos dispositivos e incorporação da endoprótese, devem predominar sobre forças gravitacionais e hemodinâmicas que tendem a arrastar a prótese no sentido caudal. Angulação, extensão e diâmetro do colo, além da medida transversa do saco aneurismático, são importantes aspectos morfológicos do aneurisma relacionados à migração. Com relação à técnica, não se recomenda implante de endopróteses com sobredimensionamento excessivo (> 30%), por provocar dilatação do colo do aneurisma, além de dobras e vazamentos proximais que também contribuem para a migração. Por outro lado, endopróteses com mecanismos adicionais de fixação (ganchos, farpas e fixação suprarrenal) parecem apresentar menos migrações. O processo de incorporação das endopróteses ocorre parcialmente e parece não ser suficiente para impedir migrações tardias. Nesse sentido, estudos experimentais com endopróteses de maior porosidade e uso de substâncias que permitam maior fibroplasia e aderência da prótese à artéria vêm sendo realizados e parecem ser promissores. Esses aspectos serão discutidos nesta revisão.

Long-term cardiovascular outcome after elective abdominal aortic aneurysm open repair

BACKGROUND

We analyzed the incidence of late cardiovascular events and mortality after elective infra-/juxtarenal abdominal aortic aneurysm open repair (AAA-OR).

METHODS

We included patients who survived AAA-OR in our center in 1988-2006. We registered late cardiac, cerebrovascular, and peripheral vascular events, as well as all-cause and cardiovascular mortality. We calculated patient survival and freedom from cardiovascular events (Kaplan-Meier) and evaluated risk factors (multivariate analysis).

RESULTS

We studied 297 patients: 292 (98.3%) men, aged 67 +/- 7 (44-83) years, 143 (48.1%) bifurcated grafts. In a mean follow-up of 78.7 +/- 52.9 months, we registered 203 cardiovascular events in 123 (41.4%) patients, at a rate of 0.16 cardiovascular events/patient-year. Eleven (3.7%) patients suffered graft-related complications. Freedom from cardiovascular events was 94.2%, 67.2%, 45.7%, and 27.6% at 1, 5, 10, and 15 years, respectively. Survival was 96.6%, 74.7%, 50.7%, and 31.5%, respectively. The main cause of death was cardiovascular disease (n = 54, 18.2%), followed by cancer (n = 43, 14.5%). Only four (1.3%) deaths were graft-related. Coronary artery disease and chronic renal failure were predictive of cardiovascular mortality (p = 0.033 and 0.006).

CONCLUSION

Although long-term survival is similar to that in the general population, successful AAA-OR patients remain at increased risk of cardiovascular events throughout their lifetime. Graft-related complications are rare, confirming the durability of the procedure.

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.

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

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

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.

Chronic obstructive pulmonary disease is not an independent marker for adverse outcomes in endograft repair of abdominal aortic aneurysms

A significant proportion of patients undergoing endograft repair of abdominal aortic aneurysms (AAAs) suffer from chronic obstructive pulmonary disease (COPD). We report here our experience and analysis of 342 consecutive AAA endograft repairs in patients with and without COPD (137, or 39%, of patients with COPD and 55, or 16%, with moderate to severe COPD). Patient outcomes such as perioperative mortality, length of admission, intensive care unit admission, congestive heart failure, myocardial infarction, conversion to open surgery, duration of surgery, postoperative endoleaks, and combined respiratory complications were analyzed; differences were not statistically significant compared to patients without COPD (p > 0.05). Endograft repair of AAA demonstrated equivalent outcomes in patients with and without COPD.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Activated coagulation during open and endovascular abdominal aortic aneurysm repair

OBJECTIVE

The study was conducted to determine activation of coagulation in patients undergoing open and endovascular infrarenal abdominal aortic aneurysm repair (EVAR).

METHODS

In a prospective, comparative study, 30 consecutive patients undergoing open repair (n = 15) or EVAR (n = 15) were investigated. Blood samples to determine fibrinopeptide A, fibrin monomer, thrombin-antithrombin complex, and D-dimer were taken up to 5 days postoperatively. Routine hematologic and hematochemical parameters as well as clinical data were collected.

RESULTS

Both groups showed comparable demographic variables. Operating time was longer in open repair (249 +/- 77 minutes vs 186 +/- 69 minutes, P < .05). Perioperatively elevated markers of coagulation were measured in both groups. Fibrinopeptide A levels did not differ significantly between the groups (P = .55). The levels of fibrin monomer and thrombin-antithrombin complex were significantly higher in patients undergoing EVAR (P < .0001), reflecting increased thrombin activity and thrombin formation compared with open surgery. The D-dimer level did not differ significantly between the groups. These results were also valid after correction for hemodilution.

CONCLUSION

These data suggest increased procoagulant activity in EVAR compared with open surgery. A procoagulant state may favor possible morbidity derived from micro- and macrovascular thrombosis, such as in myocardial infarction, multiple organ dysfunction, venous thrombosis and thromboembolism, or disseminated intravascular coagulation.

Open Versus Endovascular Abdominal Aortic Aneurysm Repair in VA Hospitals

BACKGROUND

Endovascular abdominal aortic aneurysm repair (EVAR), when compared with conventional open surgical repair, has been shown to reduce perioperative morbidity and mortality. We performed a retrospective cohort study with prospectively collected data from the Department of Veterans Affairs to examine outcomes after elective aneurysm repair.

STUDY DESIGN

We studied 30-day mortality, 1-year survival, and postoperative complications in 1,904 patients who underwent elective abdominal aortic aneurysm repair (EVAR n=717 [37.7%]; open n=1,187 [62.3%]) at 123 Department of Veterans Affairs hospitals between May 1, 2001 and September 30, 2003. We investigated the influence of patient, operative, and hospital variables on outcomes.

RESULTS

Patients undergoing EVAR had significantly lower 30-day (3.1% versus 5.6%, p=0.01) and 1- year mortality rates (8.7% versus 12.1%, p=0.018) than patients having open repair. EVAR was associated with a decrease in 30-day postoperative mortality (adjusted odds ratio[OR]=0.59; 95% CI=0.36, 0.99; p=0.04). The risk of perioperative complications was much less after EVAR (15.5% versus 27.7%; p<0.001; unadjusted OR 0.48; 95% CI=0.38, 0.61; p<0.001). Patients operated on at low volume hospitals (25% of entire cohort) were more likely to have had open repair (31.3% compared with 15.9% EVAR; p<0.001) and a nearly two-fold increase in adjusted 30-day mortality risk (OR=1.9; 95% CI=1.19, 2.98; p=0.006).

CONCLUSIONS

In routine daily practice, veterans who undergo elective EVAR have substantially lower perioperative mortality and morbidity rates compared with patients having open repair. The benefits of a minimally invasive approach were readily apparent in this cohort, but we recommend using caution in choosing EVAR for all elective abdominal aortic aneurysm repairs until longer-term data on device durability are available.

What Determines and Are the Consequences of Surveillance Intensity after Endovascular Abdominal Aortic Aneurysm Repair?

Follow-up examinations are advised 1, 3, 6, 12, 18, and 24 months and yearly thereafter by the European Collaborating Group on Stent-Graft Techniques for Abdominal Aortic Aneurysm Repair (EUROSTAR). The aim of this study was to evaluate the determinants and consequences of surveillance completeness. Patients who underwent endovascular abdominal aortic aneurysm repair between October 1996 and August 2004 and enrolled in the EUROSTAR registry were analyzed. Two groups were compared: patients who attended all scheduled visits (group A) and those who came infrequently (group B). Odds ratios and hazard rates (HRs) with 95% confidence intervals (CIs) were determined to detect which patient characteristics and complications were associated with follow-up intensity. Of the 4,433 patients, 1,538 (35%) attended all scheduled visits until the end of follow-up (group A). Analysis of patient characteristics demonstrated that intensive visitors were more often smokers, hyperlipemic, and considered unfit for open surgery or general anesthesia. Complications during follow-up, including endoleaks (24% vs. 20%), kinking (3.5% vs. 2.5%), and migration (4.9% vs. 3.5%), appeared significantly more frequently in group A. Despite intensive follow-up of this category, still a greater proportion died (12% vs. 9%, adjusted HR = 1.5, 95% CI 1.2-1.8). After 84 months of follow-up, the cumulative survival rates in groups A and B were 71% and 74%, respectively (p < 0.0001). It seems that follow-up intensity was based on baseline patient characteristics. High-risk patients had, despite more intensive surveillance, still more complications after adjustment for patient, morphological, and center-specific characteristics. Further assessment is indicated to evaluate the effectiveness of different frequencies of surveillance visits.

Secondary conversion of the Gore Excluder to operative abdominal aortic aneurysm repair

OBJECTIVE

Reports continue to document the occurrence of major adverse events after endovascular aortic aneurysm repair. Although many of these problems can be successfully managed through endovascular salvage, operative conversion with explantation of the endoprosthesis remains necessary in some patients. We report herein a review of all patients initially enrolled in multicenter US clinical trials of the Excluder endograft who underwent secondary conversion to open surgical repair.

METHODS

Clinical data and relevant medical records of patients enrolled in phase I and II multicenter US clinical trials of the Excluder endograft were retrospectively reviewed for adverse events and further narrowed to those patients who underwent secondary operative conversion. Hospital records, operative and anesthesia reports, and all imaging studies were analyzed at initial implantation and at the time of subsequent open surgical repair.

RESULTS

Late open conversion was performed in 16 (2.7%) of the 594 patients enrolled in the Excluder clinical trials. Presumed endotension accounted for 8 of 16 of secondary conversions. In two of these patients, however, an endoleak was identified at the time of open surgical repair. Of the remaining eight patients, two underwent conversion for device infection, five for persistent endoleak, and one for aneurysm rupture. The overall 30-day mortality was 6.25% (1/16), with one death occurring in a patient with a ruptured aneurysm. Of patients who underwent conversion because of endotension, the maximal abdominal aortic aneurysm diameter (mean +/- SD) at the time of initial implantation and subsequent graft removal was 61 +/- 11 mm and 70 +/- 10 mm, respectively. The mean time to open conversion for treatment of endotension was 37 +/- 12 months (range, 20-50 months; median, 42 months). Freedom from conversion was 98.6% and 96.7% at 24 and 48 months, respectively.

CONCLUSIONS

Endotension in the absence of a demonstrable endoleak has been a major indication for late surgical conversion in patients treated with the Excluder endograft. Given the potential presence of an undetected endoleak and the possible effects of progressive sac enlargement on long-term device stability, continued close surveillance of patients with assumed endotension is required. Should changes in device design eliminate endotension, a further reduction in the already low incidence of late open conversion of the Excluder endograft can be anticipated.

Risk-Adjusted Outcome Analysis of Endovascular Abdominal Aortic Aneurysm Repair in a Large Population:How Do Stent-Grafts Compare?

PURPOSE

To compare differences in the applicability and incidence of postoperative adverse events among stent-grafts used for repair of infrarenal aortic aneurysms.

METHODS

An analysis of 6787 patients from the EUROSTAR Registry database was conducted to compare aneurysm morphological features, patient characteristics, and postoperative events for the AneuRx, EVT/Ancure, Excluder, Stentor, Talent, and Zenith devices versus the Vanguard device (control) and each other. Annual incidence rates of complications were determined, and risks were compared using the Cox proportional hazards analysis.

RESULTS

The annual incidence rates were: device-related endoleak (types I and III) 6% (range 4%-10%), type II endoleak 5% (range 0.3%-11%), migration 3% (range 0.5%-5%), kinking 2% (range 1%-5%), occlusion 3% (range 1%-5%), rupture 0.5% (range 0%-1%), and all-cause mortality 7% (range 5%-8%). After adjustment for factors influencing outcome, AneuRx, Excluder, Talent, and Zenith devices were associated with a lower risk of migration, kinking, occlusion, and secondary intervention compared to the Vanguard device. Significant increased risk for conversion (EVT/Ancure) and reduced risk of aneurysm rupture (AneuRx and Zenith) and all-cause mortality (Excluder) were found compared to the Vanguard device.

CONCLUSIONS

Significant differences exist between stent-grafts of different labels in terms of applicability and complications during intermediate to long-term follow-up. Since each stent-graft has its drawbacks, no single label can be identified as the best. It is reassuring that developments in stent-grafts indeed result in better performance than the early stent-grafts. However, a single device incorporating all the perceived improvements should still be pursued.

Flow Visualization in a Model of a Bifurcated Stent-Graft

PURPOSE

To use an in vitro flow model to investigate the flow patterns in a bifurcated stent-graft for abdominal aortic aneurysm (AAA) repair.

METHODS

Experiments were performed in an in vitro test rig incorporating a simplified non-planar model of an AAA. A two-component bifurcated device consisting of a stent structure and transparent polyurethane "graft" was deployed in the AAA model. Using a blood analogue fluid, a pulsatile blood flow waveform simulating resting flow condition was produced by means of a piston pump system. Flow patterns in the lateral and anteroposterior planes of the stent-graft were recorded and analyzed using flow visualization techniques.

RESULTS

The flow patterns within the stent-graft were complex and influenced by the geometry of the stent-graft itself, as well as that of the aortic neck and iliac vessels. Regions of flow separation, low velocity and stagnation, and slow oscillatory flow near the walls were seen in the main body of the stent-graft. Constriction at the stump in the contralateral limb resulted in flow disturbances and flow separation. Kinking at the junctions of stent segments and folding of the graft compounded these complex flow structures.

CONCLUSIONS

The flow structures within stent-grafts are complex, with features that may predispose to thrombus formation. Arterial geometry, including aortic neck angulation and iliac vessel tortuosity, and the design of the stent-graft are factors that influence hemodynamics and may impact the performance of aortic stent-grafts.

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

Background

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

Methods

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

Results

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

Discussion

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

Cost-effectiveness of endovascular abdominal aortic aneurysm repair

Background

The rapid introduction of endovascular abdominal aortic aneurysm repair (EVAR) has considerable implications for the management of abdominal aortic aneurysm (AAA). This study was undertaken to determine an optimal strategy for the use of EVAR based on the best currently available evidence.

Methods

Economic modelling and probabilistic sensitivity analysis considered reference cases representing a fit 70-year-old with a 5·5-cm diameter AAA (RC1) and an 80-year-old with a 6·5-cm AAA unfit for open surgery (RC2). Results were assessed as incremental cost-effectiveness ratio (ICER) compared with open repair (RC1) or conservative management (RC2).

Results

In RC1 EVAR produced a gain of 0·10 quality-adjusted life years (QALYs) for an estimated cost of £11 449, giving an ICER of £110 000 per QALY. EVAR consistently had an ICER above £30 000 per QALY over a range of sensitivity analyses and alternative scenarios. In RC2 EVAR produced an estimated benefit of 1·64 QALYs for an incremental cost of £14 077 giving an incremental cost per QALY of £8579.

Conclusion

It is unlikely that EVAR for fit patients suitable for open repair is within the commonly accepted range of cost-effectiveness for a new technology. For those unfit for conventional open repair it is likely to be a cost-effective alternative to non-operative management. Sensitivity analysis suggests that research efforts should concentrate on determining accurate rates for late complications and reintervention, particularly in patients with high operative risks.

Treatment possibility for AAA of the visceral branches region

The authors describe a promising abdominal aortic aneurysm treatment--a combined endovascular/surgical approach--used in two cases of aneurysm taking the aortic visceral branches region.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Early outcomes of endovascular versus open abdominal aortic aneurysm repair in the National Surgical Quality Improvement Program–Private Sector (NSQIP–PS)

BACKGROUND

There remains no consensus on the appropriate application of endovascular abdominal aortic aneurysm repair (EVAR). Information from administrative databases, industry-sponsored trials, and single institutions has inherent deficiencies. This study was designed to compare early outcomes of open (OPEN) versus EVAR in a contemporary (2000 to 2003) large, multicenter prospective cohort.

METHODS

Fourteen academic medical centers contributed data to the National Surgical Quality Improvement Program-Private Sector (NSQIP-PS), which ensures uniform, comprehensive, prospective, and previously validated data entry by trained, independent nurse reviewers. A battery of clinical and demographic features was assessed with multivariate analysis for association with the principal study end points of 30-day operative mortality and morbidity.

RESULTS

One thousand forty-two patients underwent elective infrarenal abdominal aortic aneurysm (AAA) repairs: 460 EVAR and 582 OPEN. EVAR patients were older (74 vs 71 years, P < .0001), included more men (84.6% vs 79.6%, P < .05), and had a higher incidence of chronic obstructive pulmonary disease (25.4% vs 17.9%, P < .01). EVAR resulted in significantly reduced overall morbidity (24% vs 35%, P < .0001) and hospital stay (4 vs 9 days, P < .0001). Cardiopulmonary and renal function-related comorbidities had the expected significant impact on mortality for both procedures at univariate analysis ( P < .05). While crude mortality rates between EVAR and OPEN did not differ significantly (2.8% vs 4.0%) ( P = 0.32). After multivariate analysis, correlates of operative mortality included OPEN (odds ratio [OR], 2.44; 95% confidence interval [CI], 1.03 to 5.78; P < .05), advanced age (OR, 1.11; P < .001), history of angina (OR, 5.54; P < .01), poor functional status (OR, 5.78; P < .001), history of weight loss (OR, 7.42; P < .01), and preoperative dialysis (OR, 51.4; P < .0001). EVAR also compared favorably to OPEN (OR, 2.14; 95% CI, 1.58 to 2.89; P < .0001) for overall morbidity.

CONCLUSION

Significant morbidity accompanies AAA repair, even at major academic medical centers. These data strongly endorse EVAR as the preferred approach in the presence of significant cardiopulmonary or renal comorbidities, or poor preoperative functional status.

AAA elective treatment indication tactics in EVAR era

The authors describe their indication tactics for AAA elective treatment. Based on one-month morbidity and mortality they evaluate the results obtained in the past six years and compare the methods of open surgery, endovascular repair and combined strategy in AAAs elective repair.

Four-year follow up of patients with untreated abdominal aortic aneurysms

BACKGROUND

The data in the literature are still controversial describing the outcome of patients not treated for a large abdominal aortic aneurysm (AAA) especially with significant comorbidities. We followed up patients trying to establish their long-term outcome.

METHOD

Since 1998, we have prospectively followed all patients referred to our department with AAA. A retrospective analysis was carried out selecting all patients who had an AAA larger than 5 cm, and who declined or were declined for operative repair between February 1998 and November 2001.

RESULTS

One hundred and eleven patients were included in the present study. There were 78 men and 33 women. The mean age was 80 years. At the end of the study, 65 patients (59%) were deceased. Ruptured aneurysm occurred in 27 patients (median time to rupture = 14 months) with one patient surviving an emergency repair. Thirty-nine patients died from unrelated illnesses. In the 5-5.9 cm AAA group (n = 58), out of 31 deceased patients, five (16%) have died of ruptured AAA. In the 6 cm and larger AAA group (n = 53), out of 34 deceased patients, 21 (62%) have died of ruptured AAA. There was no significant difference in survival between patients with AAA below and above 6 cm in diameter (P = 0.15).

CONCLUSION

In the presence of significant comorbidities, most patients with AAA less than 6 cm died from unrelated illnesses. In the larger AAA group, the likelihood of death from AAA rupture or unrelated illnesses is almost equal.

Current Outcome of Elective Open Repair for Infrarenal Abdominal Aortic Aneurysm

The outcome of conventional elective open repair for infrarenal abdominal aortic aneurysm (AAA) has improved mainly as a result of screening to detect coronary artery disease, the main risk factor for morbidity and mortality. Our group's policy is to perform routine coronary angiography in patients scheduled to undergo elective AAA repair. The purpose of this study was to evaluate morbidity and mortality in our department using this work-up strategy. From January 1990 to December 2000 we performed elective open repair on 632 patients, including 580 men (92%) and 52 women (8%). Preoperative coronary angiography performed in 607 cases (96%) revealed significant coronary disease in 53% of patients and led to the decision to propose prior myocardial revascularization in 12.5% of cases. Mortality and morbidity in the first 30 days after AAA repair were 1.4% and 15%, respectively. Analysis with the Cox model showed that the only risk factor for mortality was chronic renal insufficiency. Our data support routine use of coronary angiography prior to AAA repair. Screening and, if necessary, treatment of coronary artery disease that is commonly associated with AAA enhances the outcome of open AAA repair.

Clinical effect of abdominal aortic aneurysm endografting: 7-year concurrent comparison with open repair

OBJECTIVE

We compared the effectiveness and clinical outcome of open repair versus endovascular aortic aneurysm repair (EVAR) in achieving prevention of abdominal aortic aneurysm (AAA)-related death and graft-related complications.

METHODS

Over 7 years from 1997 to 2003, 1119 consecutive patients underwent elective treatment of infrarenal AAAs, 585 with open repair and 534 with EVAR. Patients were regularly followed up at 1, 6, 12 months, and every 6 months thereafter, in EVAR group, and at 3 and 12 months, and yearly thereafter after open repair. Preoperative, intraoperative, and follow-up data were stored in a prospective database.

RESULTS

Median follow-up was similar in the 2 groups: 33 months (interquartile range [IQR], 13-50 months) in the EVAR group vs 35 months (IQR, 15-54 months) in the open repair group. EVAR group patients were older than patients in the open repair group: 73 years vs 72 years (P = .04). There were statistical significant differences between the EVAR group and the open repair group with respect to AAA median diameter (52 mm vs 56 mm), coronary disease rate (46% vs 37%; P = .001), pulmonary disease rate (56% vs 38%; P < .0001), and American Society of Anesthesiologists IV score rate (16% vs 6%; P < .0001). Thirty-day mortality in the EVAR group was 0.9% (5 of 534 patients), compared with 4.1% (24 of 585 patients; P = .001) in the open repair group, and major morbidity was 9.1% (49 of 534 patients) vs 18.6% (109 of 585 patients; P < .0001), respectively. The incidence of secondary procedures in the EVAR group was 15.7%, compared with 3% in the open repair group (P < .0001). There were no deaths related to secondary procedures in either group. Six AAAs (1.1%) ruptured after EVAR, 3 of which were fatal; in the open repair group 1 patient (0.2%) underwent successful repeat operatation to treat iliac pseudoaneurysm rupture 5 years after the original procedure. Kaplan-Meier estimates for freedom from aneurysm-related death at 84 months were 97.5% in the EVAR group and 95.9% in the open repair group (log rank test, P = .008). Kaplan-Meier survival estimates at 84 months were 67.1% in the open repair group and 66.9% in the EVAR group (P = NS). At the same interval the risk for secondary procedures was 49.4% for the EVAR group and 7.1% for the open repair group. Of the 11 variables analyzed with logistic analysis, open surgery (hazard ratio [HR], 11; 95% confidence interval [CI], 2.5-54.2; P = .002), American Society of Anesthesiologists IV score (HR, 7.1; 95% CI, 2.7-18.8; P = .0001), and age (HR, 1.06; 95% CI, 1.04-1.13; P = .04) were positive independent predictors of perioperative mortality.

CONCLUSION

Our data suggest that at a maximum follow-up of 7 years, patients who undergo EVAR show lower perioperative and late aneurysm-related mortality compared with a younger and substantially healthier group of patients with aneurysms treated with open repair. The higher need for secondary procedures in the endovascular group did not affect superiority of the overall performance of EVAR in the early and late intervals.

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

PURPOSE

To describe frequency, type, and outcome of re-intervention after endovascular aortic aneurysm repair (EVAR).

METHODS

Between September 1996 and December 2003, 308 patients were treated, with data collected prospectively. No patient was lost to follow up, but two were excluded (one primary conversion, and one post-operative death). Vanguard, Talent, Excluder, Zenith, and Quantum devices were used. Follow up required a CT scan before discharge. Initially, a CT scan was done at each follow up. Subsequently, we used duplex ultrasound and abdominal X-ray, with CT scan used selectively.

RESULTS

Mean follow-up was 36+/-22 months. Re-interventions were required in 47 (15%) patients, 31 (66%) elective and 16 (34%) emergency cases. In 32 patients, the primary re-intervention was successful; in 15 patients an additional 13 secondary and four tertiary re-interventions were required. A total of 72 adjunctive manoeuvres were performed: 49 endovascular (68%) and 23 open (32%). The success of endovascular re-interventions was 80%. The success of open re-interventions was 96%. Open conversions were required in nine patients (3%). There was no mortality.

CONCLUSION

EVAR was associated with a low burden of re-interventions, with only 15% patients requiring re-intervention. Our long-term follow up, without regular CT, was simple and effective.

Outcomes of secondary interventions after abdominal aortic aneurysm endovascular repair

PURPOSE

We assessed the distribution of secondary interventions after aortic stent grafting (EVAR) performed to treat infrarenal abdominal aortic aneurysm (AAA), and evaluated clinical success and survival in patients who underwent a secondary procedure (group 2) compared with patients who did not undergo a secondary procedure (group 1).

METHODS

Two hundred fifty patients (mean age, 71.3 years) with asymptomatic AAAs (mean aneurysm diameter, 54.5 mm) underwent treatment with commercially available stent grafts. Mean follow-up was 28 months (median, 25 months). Secondary procedures were defined as any additional procedures performed after initial graft placement to treat endoleak, migration, kinking, stenosis, or occlusion. Overall clinical success was defined according to reporting standards of the Society for Vascular Surgery/American Association for Vascular Surgery.

RESULTS

Sixty-eight patients (27%) required 112 secondary procedures, with a mean time from initial graft placement of 18.2 months. Patients who received grafts since removed from the market required more secondary procedures (59%, procedure:patient ratio) compared with patients who received devices still on the market (21%; P =.001). Thirty-six patients (53%) required a single secondary procedure, 24 patients (35%) required two procedures, 5 patients (10%) required three procedures, 2 patients (3%) required four procedures, and 1 patient required five secondary procedures. Ninety-eight procedures (87%) were performed with endovascular methods, including placement of 42 additional covered stent grafts (36 iliac, 6 aortic), with a success rate of 85%; 35 embolization procedures (21 lumbar, 9 internal iliac artery, 5 mesenteric), with only 23 (65%) successful; 14 angioplasty procedures, with 85% successful; 4 thrombolysis procedures, 2 of them successful (50%); and 3 successfully placed new endografts within a previous endovascular graft. Surgical secondary operations included nine femorofemoral bypass procedures and three femoral thromboendarterectomies, all of which remain patent; one cerclage of an external iliac limb; and one laparoscopic repair of a type II endoleak, which was successful. Overall clinical success rate for EVAR was 84% (211 of 250) in this series. Clinical success rate in groups 1 and 2 was 91% (166 of 182) versus 66% (45 of 68; P =.001) if all endoleaks on the most recent computed tomography scans are taken into account, and 94% (171 of 182) versus 76% (52 of 68; P =.001) if type II endoleak without aneurysm growth is not considered failure. The survival rate and rupture-free survival in groups 1 and 2 were, respectively, 97.7% +/- 1.0% and 98.5% +/- 1.4% at 1 month, 95.9% +/- 1.5% and 96.9% +/- 2.1% at 6 months, 94.4% +/- 2.0% and 93.2% +/- 3.4% at 1 year, and 80.8% +/- 5.2% and 88.5% +/- 5.0% at 3 years (P =.273, log-rank test).

CONCLUSION

With close follow-up and a significant number of secondary operations, this 8-year experience has not included any aneurysm ruptures to date. Secondary operations did not lead to increased mortality, but were associated with more surgical conversions and with a higher clinical failure rate.

Endovascular repair of abdominal aortic aneurysm without preoperative arteriography

OBJECTIVE

Clinical trials of endovascular aortic aneurysm repair (EVAR) have required both preoperative aortography and computed tomography (CT). We codeveloped specialized three-dimensional (3-D) reconstruction and computer-aided measurement, planning, and simulation software (3-D CAMPS) based on CT or magnetic resonance imaging, to eliminate the need for preoperative arteriography.

METHODS

EVAR with 3-D CAMPS as the sole preoperative imaging method was performed in 196 patients from 1996 to 2001, with six endograft types in three configurations. Physical examination, abdominal radiography, and CT (3D-CAMPS) were performed at 1, 6, and 12 months, then annually.

RESULTS

For a subset of cases in which a comparison could be made, 3-D CAMPS was superior to angiography for prediction of endograft length and iliac access. Hospital mortality was zero, and 30-day mortality was 0.5%. In three patients immediate conversion to open repair (1.5%) was necessary because of previously unknown stent-graft mechanical limits. Incidence of endoleak was 15% at 1 month, 10% at 6 months, 6% at 12 months, and 7% at 24 months, and 92% of endoleaks were type II. Mean follow-up was 18 months. Aneurysm-related mortality was zero. Nineteen secondary procedures (all endovascular) were performed in 16 patients (8%). For all graft types, freedom from secondary procedure was 94% at 1 year and 90% at 2 years, and this was better for endografts ultimately approved by the US Food and Drug Administration (96% at 1 year, 95% at 2 years; P =.02). No known measurement-related complications occurred in the series. Results for secondary intervention and endoleak compare favorably to series with similar endograft types.

CONCLUSIONS

EVAR can be performed with 3-D CAMPS as the sole preoperative imaging method to achieve outcomes comparable to the best series published for each endograft type. CT with 3-D CAMPS can effectively eliminate the need for preoperative arteriography and avert associated morbidity, expense, and exposure to contrast agent and radiation.

Abdominal aortic aneurysms: elective endovascular repair versus conventional surgery--evaluation with evidence-based medicine techniques

PURPOSE

To use evidence-based techniques to compare elective open surgical repair of abdominal aortic aneurysms with endovascular repair by means of stent placement.

MATERIALS AND METHODS

A focused clinical question formed the basis of a literature search. Evidence-based criteria were used to appraise and assign a "level of evidence" to retrieved articles. The following data were determined from the best studies: systemic, local, and/or vascular complications; graft failure rates; blood loss; mortality; length of intensive care and/or hospital stay; mid- and long-term outcomes; cost of endovascular repair versus that of surgery; and eligibility for endovascular repair. Absolute risk reductions and/or increases and numbers needed to treat or harm were calculated.

RESULTS

The best current evidence came from 22 studies, which showed that there is slight, if any, difference between mortality rates of endovascular repair and surgery. Hospital and/or intensive care stay is shorter, blood loss less, and systemic complications fewer (numbers needed to treat, two to 12) with endovascular repair. Some authors reported a significant increase in local and/or vascular complications with endovascular repair (numbers needed to harm, two to six). Graft failure is significantly more common with endovascular repair (numbers needed to harm, four), and substantive adjunctive interventions are needed. Endovascular repair is more expensive than surgery.

CONCLUSION

Elective endovascular repair has short-term benefits compared with surgery. There is slight, if any, difference in mortality. Endovascular repair costs more than surgery. At follow-up, surgical grafts performed better.

Cardiac risk stratification in patients undergoing endoluminal graft repair of abdominal aortic aneurysm: a single-institution experience with 365 patients

OBJECTIVE

Patients undergoing abdominal aortic aneurysm repair have a high incidence of coexisting cardiac disease. The traditional cardiac risk stratification for open abdominal aortic aneurysm surgery may not apply to patients undergoing endoluminal graft exclusion. The purpose of this study was to examine predictive risk factors for perioperative cardiac events.

METHODS

As part of multiple prospective endograft trials approved by the US Food and Drug Administration, data for 365 patients who underwent endoluminal graft repair from 1996 to 2001 were collected. Variables included for analysis were age and sex; history of smoking; presence of hypertension, diabetes mellitus, or renal insufficiency; Eagle clinical cardiac risk factors; American Society of Anesthesiologists index; type of anesthesia administered; estimated blood loss; preoperative hemoglobin level; preoperative use of beta-blocker therapy; duration of surgery; need for iliac artery conduit; and concomitant other vascular procedures. Univariate and multivariate logistic regression analysis were used to determine which variables were predictive of an adverse perioperative cardiac event, eg, Q wave and non-Q wave myocardial infarction (MI), congestive heart failure (CHF), severe arrhythmia, and unstable angina.

RESULTS

The study cohort included 322 men and 43 women (mean age, 74.2 years). Fifty-two (14.2%) postoperative cardiac events occurred: severe dysrhythmia in 15 patients (4.1%), MI in 14 patients (3.8%), non-Q wave MI in 8 patients (2.2%), CHF in 8 patients (2.2%), and unstable angina in 7 patients (1.9%). Univariate analysis demonstrated that age 70 years or older (P =.034), history of MI (P =.018), angina (P =.004), history of CHF (P <.001), two or more Eagle risk factors (P <.001), and lack of use of preoperative beta-blocker therapy (P =.005) were predictors of perioperative cardiac events. Multivariate analysis identified only age 70 years or older (P =.026), history of MI (P =.024) or CHF (P =.001), and lack of use of preoperative beta-blocker therapy (P =.007) as independent risk factors for an adverse cardiac event.

CONCLUSIONS

Age 70 years or older, history of MI or CHF, and lack of use of preoperative beta-blocker therapy are independent risk factors for perioperative cardiac events in patients undergoing endoluminal graft repair.

Cytokine activation and intestinal mucosal and renal dysfunction are reduced in endovascular AAA repair compared to surgery

PURPOSE

To compare endovascular (EVR) to open repair (OR) of abdominal aortic aneurysm (AAA) for cytokine activation, changes in the intestinal mucosal barrier, and renal dysfunction.

METHODS

In a prospective nonrandomized study, 15 patients admitted to a university hospital for elective infrarenal AAA repair (8 OR and 7 EVR) were recruited. Intestinal permeability was assessed preoperatively (PO), at day 1 (D1), and at day 3 (D3) after surgery using the lactulose/mannitol differential excretion (LMR) test. Renal damage was assessed from measurements of the urinary albumin:creatinine ratio (ACR); cytokine activation was based on the urinary concentration of tumor necrosis factor receptor p55 (TNF-Rp55) at the same time points. Serum creatinine and urea concentrations were measured preoperatively and daily for 5 days postoperatively.

RESULTS

A significant increase in LMR was found in the OR group at D1 and D3 compared to PO (p<0.05). The LMR increase at D3 was significantly greater in the OR group (p<0.01). A significant difference was observed in the percentage rise in ACR on D1 in the OR group compared to the EVR group (p<0.005). The urinary TNF-Rp55 concentration was significantly elevated in the OR group at D1 (p<0.05) and D3 (p<0.05) compared to baseline; in the EVR group, it was elevated at D1 (p<0.05) compared to PO. The difference was also significant for this marker between the 2 groups at D1 (p<0.01). No significant change was observed in the serum creatinine or urea concentrations in either group perioperatively.

CONCLUSIONS

Endovascular AAA repair is associated with less cytokine production and less intestinal and renal dysfunction compared to the open approach.

Contrast-enhanced ultrasound imaging for aortic stent-graft surveillance

PURPOSE

To compare unenhanced and enhanced ultrasound imaging to computed tomographic angiography (CTA) or magnetic resonance angiography (MRA) for surveillance of aortic endografts.

METHODS

Thirty consecutive patients (29 men; mean age 69 years, range 50-82) who underwent endovascular aortic aneurysm repair agreed to participate in a follow-up program. Patients underwent CTA (26/30) or MRA (4/30), plain abdominal radiography, and unenhanced and enhanced ultrasound examinations at 3, 12, and 24 months to evaluate aneurysm diameter, endoleaks, and graft patency. The accuracy of ultrasound was compared with CTA or MRA as the reference standards.

RESULTS

Twenty-six patients reached the 24-month assessment (mean follow-up 30 months, range 6-60). All endoleaks detected by CTA or MRA were confirmed by enhanced ultrasound; the aneurysm diameter in these patients remained unchanged or increased. In patients without endoleaks on any imaging method, the sac diameter remained unchanged or decreased. Endoleaks disclosed by enhanced ultrasound alone, all type II, numbered 16 at 3 months, 6 at 12 months, and 3 at 24 months. In this group, the aneurysm diameter remained unchanged or increased. Enhanced ultrasound yielded 100% sensitivity in detecting endoleaks, but compared with CTA and MRA, all endoleaks detected by enhanced ultrasound alone were false positives (mean specificity 65%). Nevertheless, because changes in the postoperative aneurysm diameter were similar in patients with endoleaks detectable on CTA/MRA and on enhanced ultrasound ("true positives") and in those with endoleaks detectable only on enhanced ultrasound ("false positives"), some endoleaks were possibly "true positive" results.

CONCLUSIONS

Enhanced ultrasound is a useful method in the long-term surveillance of endovascular aortic aneurysm repairs, possibly in association with CTA or MRA. Enhanced ultrasound also seems able to identify endoleaks missed by other imaging techniques, but this conclusion awaits further investigation.

Endovascular treatment of aneurysmal disease

Endovascular repair of abdominal aortic aneurysm using stent grafts that are delivered intraluminally by catheters is a less invasive alternative to open surgical repair. Endovascular surgery has been studied for over a decade, and early results are comparable to open repair. With extended follow-up care, however, postoperative complications and graft failures have been reported in some patients, resulting in reintervention, conversion to open repair, and death. The high incidence of secondary interventions causes some researchers to question the durability of endograft repair and emphasizes the need for detailed long-term follow-up care. This article describes the evolution of endovascular treatment of abdominal aortic aneurysm from its origin to its current state and discusses the future direction of endovascular therapy.

Elective endovascular versus open surgical repair of abdominal aortic aneurysms: systematic review of short-term results

PURPOSE

To summarize and compare published short-term results of elective endovascular and open surgical repair of abdominal aortic aneurysms.

MATERIALS AND METHODS

A MEDLINE search of the English literature was performed. Studies with at least 10 patients in each treatment group were included if they reported patient characteristics, complications, and mortality. Two reviewers independently extracted the data. A random-effects model was used to pool the data and calculate pooled odds ratios (endovascular vs open surgical repair).

RESULTS

Nine studies were included, reporting results of 1,318 procedures (687 endovascular repair and 631 open surgical repair). Mean blood loss was 456 mL for endovascular repair and 1,202 mL for open surgical repair (P =.003). On average, patients undergoing endovascular repair spent 0.5 days in the intensive care unit and 3.9 days in the hospital, and patients undergoing open surgical repair spent 2.2 days (P =.04) in the intensive care unit and 10.3 days (P =.02) in the hospital. The pooled 30-day-mortality was 0.03 for endovascular repair (95% CI: 0.02, 0.04) and 0.04 for open surgical repair (95% CI: 0.00, 0.07) (P =.03), and the odds ratio was 0.55 (95% CI: 0.33, 0.92). The pooled local and/or vascular complication rate was 0.16 for endovascular repair (95% CI: 0.06, 0.25) and 0.12 for open surgical repair (95% CI: 0.06, 0.18) (P =.46), and the odds ratio was 0.97 (95% CI: 0.62, 1.54). The pooled systemic and/or remote complication rate was 0.17 for endovascular repair (95% CI: 0.09, 0.25) and 0.44 for open surgical repair (95% CI: 0.21, 0.66) (P <.001), and the odds ratio was 0.22 (95% CI: 0.11, 0.45).

CONCLUSION

On the basis of this systematic review, endovascular repair results in less blood loss, shorter intensive care unit and hospital stays, lower 30-day mortality, and lower systemic and/or remote complication rates than those of open surgical repair.