Disparate outcome after endovascular treatment of small versus large abdominal aortic aneurysm

Excess Mortality for Abdominal Aortic Aneurysms and the Potential of Strict Implementation of Cardiovascular Risk Management: A Multifaceted Study Integrating Meta-Analysis, National Registry, and PHAST and TEDY Trial Data

OBJECTIVE

Previous studies imply a profound residual mortality risk following successful abdominal aorta aneurysm (AAA) repair. This excess mortality is generally attributed to increased cardiovascular risk. The aim of this study was (1) to quantify the excess residual mortality for patients with AAA, (2) to evaluate the cross sectional level of cardiovascular risk management, and (3) to estimate the potential of optimised cardiovascular risk management to reduce the excess mortality in these patients.

METHODS

Excess mortality was estimated through a systematic review and meta-analysis, and through data from the Swedish National Health Registry. Cardiovascular risk profiles were individually assessed during eligibility screening of patients with AAA for two multicentre pharmaceutical AAA stabilisation trials. The potential of full implementation of cardiovascular risk management was estimated through the validated Second Manifestations of ARTerial disease (SMART) risk scores algorithm.

RESULTS

The meta-analysis showed a similarly impaired survival for patients who received early repair (small AAA) or regular repair (≥ 55 mm), and a further impaired survival for patients under surveillance for a small AAA. Excess mortality was further quantified using Swedish population data. The data revealed a more than quadrupled and doubled five year mortality rate for women and men who had their AAA repaired, respectively. Evaluation of the level of risk management of 358 patients under surveillance in 16 Dutch hospitals showed that the majority of patients with AAA did not meet therapeutic targets set for risk management in high risk populations, and indicated a more pronounced prevention gap in women. Application of the SMART risk score algorithm predicted that optimal implementation of risk management guidelines would reduce the 10 year risk of major adverse cardiovascular events from 43% to 14%.

CONCLUSION

Independent of the rupture risk, AAA is associated with a worryingly compromised life expectancy with a particularly poor prognosis for women. Optimal implementation of cardiovascular risk prevention guidelines is predicted to profoundly reduce cardiovascular risk.

Characterizing the frequency and indications for repair of abdominal aortic aneurysms with diameters smaller than recommended by societal guidelines

OBJECTIVE

While the Society for Vascular Surgery recommends repair of abdominal aortic aneurysms (AAA) at ≥5.5 cm in men and ≥5.0 cm in women, AAA repair below these thresholds has been well documented. There are clear indications for repair other than these strict size criteria, but the expected proportion of such repairs in one's practice has not been studied. We sought to characterize the indications for repairs of aneurysms below diameter recommendations at a single academic center. Using the assumption that this real-world experience would approximate that of other practices, we then used national data to extrapolate these findings.

METHODS

A single-center retrospective review was conducted of all elective open (oAAA) and endovascular (EVAR) AAA repairs (2010-20) to assess the incidence of and indications for repair of aneurysms below diameter recommendations (defined as <5.5cm in men and <5.0cm in women). Reasons for these repairs were defined as: 1) iliac aneurysm, 2) saccular morphology, 3) rapid expansion, 4) patient anxiety, 5) distal embolization, 6) other, and 7) no documented reason. The Vascular Quality Initiative (VQI) was queried for all asymptomatic oAAA and EVAR (2010-20) and repairs below diameter recommendations were identified. Findings from the single-center analysis were applied to the VQI cohort to extrapolate estimates of reasons for repairs done nationally. In-hospital mortality and major adverse cardiac events (MACE) were compared between those below size recommendations and those meeting size recommendations.

RESULTS

Of 456 elective AAA repairs at our center, 147 (32%) were below size recommendations. This was more common for EVAR (35% vs 28%). Reasons were: not documented (41%), iliac aneurysm (23%), saccular (10%), rapid expansion (10%), patient anxiety (7%), other (6%), and distal embolism (3%). Of 44,820 elective AAA repairs in VQI, 17,057 (38%) were below size recommendations (40% EVAR, 26% oAAA). Patients who were repaired below size recommendations had lower in-hospital death (oAAA: 2.4% vs 4.6% p<0.0001; EVAR: 0.3% vs 0.8% p<0.0001). When single-center findings were applied to the VQI dataset, an estimated 10,064 repairs were performed nationally for acceptable indications other than size criteria. Conversely, there may have been 6993 repairs (with an associated 35 deaths) performed without documented indication.

CONCLUSION

Repairs for AAA below recommended diameter guidelines account for approximately one third of all elective AAA procedures in both VQI and our single-center experience. Assuming our practice is typical, nearly 60% of repairs below size recommendations meet criteria for other clear reasons. The remaining 40% lack a documented reason, meaning 13% of all elective AAA repairs were done for aneurysms below size recommendations without an acceptable indication. As awareness of overuse/underuse is heightened, these data help estimate the expected proportion of repairs for less common pathologies. They also provide a potential baseline data point for efforts at reducing overuse.

Unibody design for aortic disease with a narrow aortic bifurcation: tips and tricks for success

Background

Surgical management of patients with abdominal aortic diseases associated with distal narrowing is a challenging situation.

Objectives

To evaluate outcomes of unibody bifurcated endovascular stent graft repair.

Methods

This is a retrospective, observational, multi-institutional database study of a cohort of consecutive cases, approved by the local Ethics Committee. Records were reviewed of patients diagnosed from 2010 to 2020 with “shaggy” aorta, saccular aneurysm, penetrating aortic ulcer, and isolated aortic dissection located in the infrarenal abdominal aorta. All patients were treated with a unibody bifurcated stent graft. Main outcomes were technical success, procedure complications, long-term patency, and mortality in the follow-up period up to 5 years. Data on demographics, comorbidities, surgical management, and outcomes were analyzed.

Results

Twenty-three patients were treated with unibody bifurcated stent graft repair, including 7 cases of “shaggy” aorta, 3 isolated dissections of the abdominal aorta, 4 penetrating aortic ulcers, and 9 saccular aneurysms. Immediate technical success was achieved in 100% of cases. At follow-up, all stent grafts remained patent and there were no limb occlusions. The patients were symptom-free and reported no complications related to the procedure. There were 5 deaths during the follow-up period (median= 4 years), but none were related to the procedure and there were no aorta-related deaths.

Conclusions

The present study shows that unibody bifurcated stent grafting is safe and effective in this group of patients with narrow distal abdominal aorta and complex aortic pathology. The results were similar for both infrarenal aortic aneurysms and aorto-iliac atherosclerotic disease.

The Effect of Abdominal Aortic Aneurysm Size on Endoleak, Secondary Intervention and Overall Survival Following Endovascular Aortic Aneurysm Repair

OBJECTIVE

The purpose of this study was to identify the effect of abdominal aortic aneurysm (AAA) size on endoleak development and secondary intervention after endovascular repair (EVAR), as well as to examine the effect on overall survival and cause of mortality.

METHODS

Retrospective analysis was performed on all non-ruptured AAA treated by elective EVAR using FDA-approved endografts in our facility from July 2004 to December 2017. Patients were grouped into 3 cohorts based on preoperative aneurysm size: Group I (<5.5 cm), Group II (5.5-6.4 cm), and Group III (≥ 6.5 cm). Occurrences of endoleak, secondary intervention and overall survival underwent univariate and multivariate analysis. Cause of death data on deceased patients was similarly examined.

RESULTS

A total of 517 patients were analyzed. There was no difference between size groups in the rate of endoleak (Group I 48/277, 17.3%; Group II 33/160, 20.6%; Group III 18/80, 22.5%; p = 0.46) or time until endoleak development. Univariate analysis showed no difference in the rate of secondary intervention (Group I 36/277, 13.0%; Group II 24/160, 15.0%; Group III 18/80, 22.5%; p = 0.11), time until intervention or number of interventions performed. Multivariate analysis showed an association with shorter time to secondary intervention for both Group III aneurysms (HR 2.03, 95% CI 1.11-3.73; p = 0.02) and female patients (HR 1.79, 95% CI 1.02-3.13; p = 0.04). There was no difference in overall survival, aneurysm-related mortality or overall cause of mortality.

CONCLUSION

AAA diameter prior to EVAR was not associated with any differences in rates of endoleak or secondary intervention, and was not associated with poorer overall survival or greater aneurysm-related mortality. Patients with suitable anatomy for EVAR can be considered for this intervention without concern for increased complications or poorer outcomes related to large aneurysm diameter alone.

Late outcomes after endovascular and open repair of large abdominal aortic aneurysms

OBJECTIVE

The risk of aortic abdominal aneurysm (AAA) rupture increases with an increasing aneurysm diameter. However, the effect of the AAA diameter on late outcomes after aneurysm repair is unclear. Therefore, we assessed the association of a large AAA diameter with late outcomes for patients undergoing open and endovascular AAA repair.

METHODS

We identified all patients who had undergone elective open or endovascular infrarenal aneurysm repair from 2003 to 2016 in the Vascular Quality Initiative linked to Medicare claims for long-term outcomes. A large AAA diameter was defined as a diameter >65 mm. We assessed the 5-year reintervention, rupture, mortality, and follow-up rates. We constructed propensity scores and used inverse probability-weighted Kaplan-Meier estimations and Cox proportional hazard models to identify independent associations between large AAA repair and our outcomes.

RESULTS

Of the 21,119 aneurysm repairs identified, 15.2% were for large AAAs. Of the 21,119 repairs, 19,017 were endovascular and 2102 were open. The large AAA cohort was less likely to have undergone endovascular aneurysm repair (EVAR; 84.9% vs 91%; P < .001), more likely to be older (median age, 76 vs 75 years; P < .001), and were less likely to be women (16.2% vs 21.7%; P < .001). After EVAR, patients with large AAAs had had lower adjusted 5-year freedom from reintervention (73.9% vs 84.6%; P < .001), freedom from rupture (88.5% vs 93.6%; P < .001), survival (58.0% vs 66.4%; P < .001), and freedom from loss to follow-up (77.7% vs 83.3%; P < .001) compared with patients with smaller AAAs. However, after open repair, the adjusted 5-year freedom from reintervention (95.8% vs 93.3%; P = .11), freedom from rupture (97.4% vs 97.8%; P = .32), survival (70.4% vs 74.0%; P = .13), and loss to follow-up (60.5% vs 62.8%; P = .86) were similar to the results for patients with smaller AAAs. For patients with large AAAs, the adjusted 5-year survival was lower after EVAR than that after open repair (55.3% vs 63.7%) but not after smaller AAA repair (67.3% vs 70.6%).

CONCLUSION

The 5-year adjusted reintervention, ruptures, mortality, and loss to follow-up rates for patients who had undergone large AAA EVAR were higher than those for patients who had undergone small AAA EVAR and large AAA open repair. Therefore, for patients with large AAAs who are medically fit, open repair should be strongly considered. Furthermore, these findings highlight the necessity for rigorous long-term follow-up after EVAR.

Increasing disparity between Society for Vascular Surgery guidelines for infrarenal abdominal aortic aneurysm repair and real-world practice

OBJECTIVE

The current Society for Vascular Surgery (SVS) guidelines, based on randomized controlled trials published more than a decade ago, recommend a minimum threshold diameter of 5.5 cm for infrarenal abdominal aortic aneurysm (iAAA) repair. It is unknown whether practice patterns with respect to size of repair have changed since the publication of these guidelines. We aimed to evaluate the real-world practice of vascular surgeons in our region with respect to iAAA size at the time of repair, whether this has changed over the past 12 years and if any changes were associated with the repair type, open vs endovascular.

METHODS

The Vascular Study Group of New England (VSGNE) database was used to identify all patients who received iAAA repair between 2003 and 2015. The primary end point was to quantify the annual percentage of iAAAs repaired in different size categories (≥5.5 cm; <5.5 cm but ≥5.0 cm; <5.0 cm) over the study time period and by type of repair. The secondary end points were morbidity and mortality in these groups. We excluded nonelective cases (ruptured or symptomatic), patients with coexisting iliac artery aneurysms, and those missing critical data.

RESULTS

A total of 5314 patients with iAAA repairs (1538 open, 3776 endovascular) were identified in the VSGNE database during the study period. In 40% (2110 of 5314) of patients, repair was performed for aneurysms <5.5 cm, with endovascular aneurysm repair (EVAR) comprising 75% (1581 of 2110) and open 25% (529 of 2110). More EVARs were performed for <5.5 cm in 2015 (46%) compared with 2003 (33%) (P < .05, n - 1 χ²) with an average increase of 1.1%/y. There was also a non-statistically significant increase in open repair of small aneurysms (0.7%/y; P = .759). Overall, 30-day mortality was 1.11% in the EVAR group (0.54% in <5.0 cm, 0.91% in ≥5.0 but <5.5 cm, and 1.55% in ≥5.5 cm), compared with 3% in the open group (2.88%, 1.79%, and 3.77%, respectively) with no significant change in mortality in either group over time.

CONCLUSIONS

Despite the SVS guidelines suggesting surveillance rather than repair of iAAA <5.5 cm, an increasing proportion of repairs in the VSGNE database were performed below that threshold. The reasons for this are likely multifactorial and might include a lesser complexity and lower operative mortality for smaller aneurysms and markedly improved third- and fourth-generation stent graft technology with possibly better long-term survival. As such, it may be time to re-examine the current guidelines for iAAA repair.

Long-term freedom from aneurysm-related mortality remains favorable after endovascular abdominal aortic aneurysm repair in a 15-year multicenter registry

OBJECTIVE

Endovascular aneurysm repair (EVAR) has become the preferred approach to abdominal aortic aneurysm (AAA) because of lower early morbidity and mortality than open repair. However, the ability of EVAR to prevent long-term aneurysm-related mortality (ARM) has been questioned in light of recent trial data. We have updated our long-term EVAR experience in a large multicenter registry to further examine this issue.

METHODS

Between 2000 and 2010, 1736 patients with AAA underwent EVAR in a large integrated regional healthcare system. We extended follow-up in this previously reported cohort through 2015 and identified predictors associated with ARM and need for major reintervention. The primary outcome was ARM. Secondary outcomes were all-cause mortality, delayed aneurysm rupture, major adverse event, major reintervention, sac growth of more than 5 mm, and type I or III endoleak. End points were analyzed for the whole cohort and compared for patients who underwent EVAR during the earlier (2000-2005) and latter (2006-2010) halves of the enrollment period to assess for changes in outcomes over time of repair.

RESULTS

The overall follow-up rate was 96.3%, and median follow-up was 5.5 years (interquartile range, 2.8-7.7 years). During the study period, 958 patients died, of whom 63 experienced ARM (6.6%). Overall crude rate of freedom from ARM was 96.4%. Delayed aneurysm rupture was seen in 1.3% (n = 23), with a median time to event of 4.1 years (interquartile range, 1.7-7.2 years). Major adverse events occurred in 12.4% of patients, and major reintervention was performed in 10.3%. Overall freedom from major adverse event or major reintervention was seen in 84.0%. Significant predictors of ARM included female sex, age 80 to 89 years, urgent EVAR, and any major reintervention. The unadjusted cumulative probability of all-cause survival was significantly higher in the late group than the early group at 5 years (66.8% vs 59.8%; P = .01, log-rank test); however, freedom from ARM at 5 years was not significantly different (96.5% and 97.1%, respectively; P = .67, log-rank test).

CONCLUSIONS

Our results demonstrate favorable long-term freedom from major adverse event or major reintervention after EVAR and extremely low rates of ARM and delayed rupture. Our findings support EVAR as a safe, long-term solution for managing patients with AAA and provide insight into clinical parameters that can be used to stratify patients' post-EVAR surveillance and need for reintervention.

Effects of Abdominal Aortic Aneurysm Size on Mid- and Long-term Mortality After Endovascular Aneurysm Repair

Purpose: To investigate the effect of abdominal aortic aneurysm (AAA) size on mid- and long-term survival after endovascular aneurysm repair (EVAR). Materials and Methods: Retrospective data were collected from 325 consecutive patients (mean age 69.7 ± 8.5 years; 323 men) who underwent EVAR for intact AAA at a single institution between January 2003 and December 2013. The primary endpoint was death at 3, 5, and 10 years after EVAR. Optimal cutoff points for AAA size and age were determined using receiver operating characteristics (ROC) curves. Time to event analyses (Kaplan-Meier curves and Cox proportional hazard models) were employed to determine any differences in all-cause mortality outcomes between AAA size groups. Cox models were adjusted for age and other comorbidities (hypertension, hyperlipidemia, coronary artery disease, smoking status, symptomatic status, and creatinine); the outcomes are reported as the hazard ratio (HR) with 95% confidence interval (CI). Results: The cohort was dichotomized according to the ROC analysis, which defined an optimal cutoff point of 5.6 cm for AAA size and >70 years for age. The mean follow-up period post EVAR was 45.5±29.2 months. In total, 134 (41.2%) patients died during the 10-year follow-up. Thirty-day mortality was 1.1% (2/184) in the patients with AAA <5.6 cm and 2.1% (3/141) in patients with AAA ≥5.6 cm (p=0.45). All-cause mortality was not significantly affected by comorbidities. However, AAA size ≥5.6 cm was associated with increased 3-year mortality risk (HR 1.59, 95% CI 1.001 to 2.52, p<0.049) but not 5-year (HR 1.44, 95% CI 0.98 to 2.10, p=0.062) or 10-year mortality (HR 1.28, 95% CI 0.91 to 1.80, p=0.149). After adjusting for comorbidities, AAA size ≥5.6 cm was no longer significantly associated with morality at any time point. Using a larger size cutoff (AAA size ≥6.0 cm) resulted in improved statistical significance in the unadjusted model. In the adjusted Cox model, AAA size ≥6.0 cm was significantly associated with increased risk of mortality at 3 years (HR 1.67, 95% CI 1.01 to 2.77, p<0.047), but not at longer time points. Conclusion: Our study demonstrates that midterm survival after EVAR is significantly and independently associated with AAA size even after correcting for comorbidities. However, in the long term, preoperative AAA size is not an independent predictor of mortality.

Survival and Reintervention Risk by Patient Age and Preoperative Abdominal Aortic Aneurysm Diameter after Endovascular Aneurysm Repair

BACKGROUND

Endovascular aneurysm repair (EVAR) has become the standard of care for abdominal aortic aneurysm (AAA), but questions remain regarding the benefit in high-risk and elderly patients. The purpose of this study was to examine the effect of age, preoperative AAA diameter, and their interaction on survival and reintervention rates after EVAR.

METHODS

Our integrated health system's AAA endograft registry was used to identify patients who underwent elective EVAR between 2010 and 2014. Of interest was the effect of patient age at the time of surgery (≤80 vs. >80 years old), preoperative AAA diameter (≤5.5 cm vs. >5.5 cm), and their interaction. Primary endpoints were all-cause mortality and reintervention. Between-within mixed-effects Cox models with propensity score weights were fit.

RESULTS

Of 1,967 patients undergoing EVAR, unadjusted rates for survival at 4 years after EVAR was 76.1%, and reintervention-free rate was 86.0%. For mortality, there was insufficient evidence for an interaction between age and AAA size (P = 0.309). Patient age >80 years was associated with 2.53-fold higher mortality risk (hazard ratios [HR] = 2.53; 95% confidence intervals [CI], 1.73-3.70; P < 0.001), whereas AAA > 5.5 cm was associated with 1.75-fold higher mortality risk (HR = 1.75; 95% CI, 1.26-2.45; P = 0.001). For reintervention risk, there were no significant interactions or main effects for age or AAA diameter.

CONCLUSIONS

Age and AAA diameter are independent predictors of reduced survival after EVAR, but the effect is not amplified when both are present. Age >80 years or AAA size >5.5 cm did not increase the risk of reintervention. No specific AAA size, patient age, or combination thereof was identified that would contraindicate AAA repair.

Endovascular Repair of Small Abdominal Aortic Aneurysms: A Paradigm Shift?

Recent reports have documented poor long-term results following endovascular aneurysm repair (EVAR) of large abdominal aortic aneurysms (AAA). EVAR of small AAAs may result in improved long-term results compared to large AAAs. It is not known whether the frequency of anatomic suitability for EVAR is increased for small compared to large AAAs. This study compared the anatomic suitability of large and small AAAs for EVAR in an unselected patient population. Radiology reports for all computed tomography (CT) scans in a single hospital over a recent 3-year period were reviewed. AAAs diagnosed by contrasted CT scans with cuts >7 mm were excluded. Suitability for EVAR was determined by neck diameter, length, and angulation. In addition, iliac diameters and common iliac distal landing zone lengths were determined. Computerized 3-dimensional (3D) reconstruction was used to measure neck angulation and total aortic tortuosity. One hundred ninety-one patients were found to have AAAs with adequate CT scans for evaluation. Suitability for EVAR was highest in patients with AAA diameters of 3–4 cm and declined with increasing size of the AAA. Dividing AAAs into sizes greater than or less than 5.5 cm revealed that small AAAs had significantly longer necks, less neck angulation, longer common iliac landing zones, and less total aortic tortuosity. Multivariable analysis revealed that maximal aortic diameter was the only independent predictor of suitability for EVAR (p = 0.005, odds ratio 1.67, CI 95% = 1.17 to 2.38). The odds ratio predicts that with each 1 cm increase in size, the likelihood of suitability decreased by 5.3-fold. Small AAAs have less complex anatomy with longer aortic necks, less neck angulation, and less tortuosity. The poor outcomes following the treatment of large AAAs is thought to be due to complex anatomy. EVAR of less anatomically challenging small AAAs may improve longterm outcomes.

Abdominal aortic aneurysm repair: long-term follow-up of endovascular versus open repair

INTRODUCTION

To compare early and long-term outcomes of endovascular abdominal aortic aneurysm repair (EVAR) versus open repair (OPEN).

DESIGN

Prospective observational, per protocol, non-randomized, with retrospective analyses.

MATERIAL AND METHODS

Between 2000 and 2005, a total of 311 patients having EVAR or OPEN repair of infrarenal abdominal aortic aneurysms were identified and included in this prospective single-center observational study. A propensity score-based optimal-matching algorithm was employed, and 138 patients undergoing EVAR procedures were matched (1: 1) to OPEN repair.

RESULTS

Open repair showed higher hospital mortality (17% vs. 6%, p = 0.004), respiratory failure (p < 0.026), transfusion requirement (p < 0.001), and intensive care unit admission (27% vs. 7%, p < 0.001), and longer hospitalization (p < 0.001). Median follow-up was 70 months (25(th) to 75(th) percentile, 24 to 101). Actuarial survival estimates at 1, 5 and 10 years were 93%, 74%, 49% for the OPEN group compared to 89%, 69%, 59% for the EVAR group (p = 0.465). A significant difference between groups was observed in younger patients (< 75 years) only (p < 0.044). Late complication and re-intervention rates were significantly higher in EVAR patients (p < 0.001 and p = 0.002, respectively). Freedom from late complications at 1, 5 and 10 years was 96%, 92%, 86%, and 84%, 70%, 64% for OPEN and EVAR procedures, respectively.

CONCLUSIONS

Our experience confirms the excellent results of the EVAR procedures, offering excellent early and long-term results in terms of safety and reduction of mortality. Patients < 75 years seem to benefit from EVAR not only in the immediate postoperative period but even in a long-term perspective.

[Treatment of abdominal aortic aneurysms]

The treatment of abdominal aortic aneurysms (AAA) has changed significantly since the introduction of endovascular aortic repair (EVAR). In terms of perioperative morbidity and mortality, randomized multicenter trials revealed results in favour of EVAR compared to open reconstruction. However, EVAR is associated with possible late complications caused by endoleaks, stent migration, kinking and/or overstenting of side branches, making life-long follow-up necessary. Since the majority of patients requiring therapy are elderly and exhibit attendant comorbidities, EVAR has become the procedure of choice in those patients with favourable anatomy. Medicamentous and conservative treatment may be relevant in patients with small to medium-sized aneurysms. Since smoking is one of the major risk factors for the development of AAA, all patients should be advised to stop smoking. Studies on long-term statin therapy in patients following surgical AAA repair showed a reduction in both overall and cardiovascular mortality; AAA patients should therefore receive statins for secondary prevention.

Is the abdominal aortic aneurysm rupture rate decreasing?

Decreased smoking has likely had the most significant impact on reducing the prevalence of AAAs. In a review of public data in England and Wales, Anjum and colleagues illustrated a reduction of AAA rupture from 1997 to2009 across all ages attributed to a concurrent decrease in prevalence of smoking. This trend has also been noted in a meta-analysis from Sweeting and colleagues and attributed to a reduction in the prevalence of smoking since the mid-1970s along with an enhanced awareness of cardiovascular risk factor reduction and selective aneurysm screening. Along with an effort to reduce AAA progression and rupture, tools to predict patient-specific risk of AAA rupture are evolving with refined models that incorporate both aneurysm wall stress and wall strength likely to provide the most promising approach. Although the role of statins, ACE inhibitors, beta-blockers, and aspirin in preventing or slowing aneurysmal rupture remains unresolved, their proven benefit in reducing long-term cardiovascular mortality suggests that these medications should be considered in any patient with a small AAA. Currently, randomized trials do not show any survival benefit for open or endovascular repair for small aneurysms in the range of 4.0 to 5.4 cm. AAA repair, whether through an endovascular or open approach, is not without potential complication. Even at centers of excellence, the 30-day mortality rate for conventional AAA surgery is 3% to 5%, with rates of major morbidityranging from 15% to 40%. The Society for Vascular Surgery guidelines recommends surveillance for patients with a fusiform AAA of 4.0 to 5.4 cm. The risk of AAA rupture appears to be decreasing through heightened public awareness, advanced technology for AAA detection, screening and surveillance, improved understanding of biomechanics and natural progression in AAA rupture, along with the availability of a wide range of medical therapies for risk factor reduction and minimally invasive options for AAA repair.

Suitability of endovascular repair with current stent grafts for abdominal aortic aneurysm in Korean patients

Suitability rate of endovascular aneurysm repair (EVAR) and the anatomic features causing unsuitability have not been well determined in Asian patients who have abdominal aortic aneurysm (AAA). In a single Korean center, a total of 191 patients with abdominal aortic aneurysm (maximal diameter ≥ 4 cm) were identified. Aortoiliac morphologic characteristics in contrast-enhanced computed tomography images were retrospectively reviewed to determine suitability for EVAR with four FDA-approved stent-grafts. AAA was considered ideally suitable for EVAR in 46.6% of patients. The most frequent causes for unsuitability were common iliac artery (CIA) aneurysm (61.8%) and excessive neck angulation (52.9%). Problems such as small and/or short neck and small access were found in minor incidences. If CIA aneurysm is dealt by overstenting with sacrifice of internal iliac artery, suitability rate can increase to 65%. Larger aneurysms were more frequently unsuitable for EVAR and had more chance of having multiple unfavorable features. In conclusion, the overall feasibility rate for EVAR in Korean patients was not different from that in Western patients. However, considering the difference in the major causes of unsuitability, more attention has to be paid to neck angulation and CIA aneurysm to provide EVAR for more Korean patients especially who have large aneurysm.

Endovascular treatment of elective abdominal aortic aneurysms: independent predictors of early and late mortality

BACKGROUND

The purpose of this study was to review our personal experience with patients who underwent elective endovascular repair of abdominal aortic aneurysms so as to detect the predictors of early and late mortality.

METHODS

Between November 2000 and June 2008, a total of 235 consecutive patients (218 men; mean age: 71.9 ± 8.0 years, range: 48-95 years) underwent endovascular repair of abdominal aortic aneurysms. Comorbidities were defined by using the Society for Vascular score grading system and the preoperative risk grade on the basis of the classification of the American Society of Anesthesiologists (ASA). Physical examination and spiral computed tomography were planned at 1, 4, and 12 months after the procedure, and on a yearly basis thereafter. Contrast-enhanced ultrasonography and plain X-rays were also performed.

RESULTS

Primary technical success rate was 97% (228 of 235 cases). The overall hospital mortality was 2.1% (n = 5), ranging from 1.2% and 2.8% for patients with an ASA of score 2 and 3, respectively, to 7.7% for patients with an ASA score of 4. Multivariable analysis confirmed chronic renal failure (OR: 12.12, 95% CI: 1.83-80.17, p = 0.010) and transrenal endograft (OR: 9.61, 95% CI: 1.01-91.57, p = 0.049) as the only independent predictors of early mortality. Follow-up was completed for all 230 patients who were discharged, with a mean follow-up period of 26.3 ± 22.7 months (maximum: 92 months). Kaplan-Meier analysis revealed a reduced survival rate for older patients (p < 0.001) and patients with a larger aneurysm (p < 0.001). A reduced survival rate was also demonstrated for women and patients with higher ASA scores (p = 0.007, and p = 0.003, respectively). In multivariate Cox analysis, ASA score, age, diameter of the aneurysm, and being female independently affected long-term survival.

CONCLUSION

On the basis of our experience, it was concluded that chronic renal failure and the endograft configuration were independent predictors of early mortality. Also, older patients, women, and patients with larger aneurysms and higher ASA scores had the poorest late survival rates.

Should the size threshold for elective abdominal aortic aneurysm repair be lowered in the endovascular era? No

According to the current international guidelines, patients with infrarenal or juxtarenal abdominal aortic aneurysms (AAAs) measuring > or = 5.5 cm should undergo repair to reduce the risk of rupture. The 5.5-cm-diameter threshold is the size when the AAA rupture rate balances the mortality rates of elective open surgical AAA repair (3%). Endovascular AAA repair (EVAR) is associated with lower perioperative mortality and complication rates compared with open surgical repair. This debate addresses the issue whether the current size threshold for elective AAA repair needs to be lowered in the endovascular era. This article supports the position that the size threshold for AAA repair should not be lowered.

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.

Randomized clinical trials of endovascular repair versus surveillance for treatment of small abdominal aortic aneurysms

The Aneurysm Detection and Management (ADAM) trial and the United Kingdom Small Aneurysm Trial (UKSAT) demonstrated that early open surgical repair of small (<5.5 cm in diameter) abdominal aortic aneurysms (AAAs) conveyed no benefits compared with surveillance. In 2 randomized controlled trials (RTCs), operative mortality rates were significantly lower with endovascular aneurysm repair (EVAR) than with open surgery for treatment of large AAAs. Retrospective analyses of EVAR databases suggested that EVAR outcomes are directly related to aneurysm size and are better for smaller AAAs. It has thus seemed logical that a less invasive treatment strategy might be beneficial in treating patients with small AAAs. Two new RCTs have been initiated to evaluate early EVAR versus surveillance in patients with small AAAs. The European-based 17-site CAESAR (Comparison of surveillance vs Aortic Endografting for Small Aneurysm Repair) trial had enrolled 740 patients with small AAAs (4.1-5.4 cm) for surveillance or EVAR with the Zenith stent-graft. The primary endpoint of CAESAR is all-cause mortality at 54 months. The 70-site PIVOTAL (Positive Impact of endoVascular Options for Treating Aneurysm earLy) trial in the United States is enrolling up to 1025 patients with small AAAs (4-5 cm) for surveillance or EVAR with the AneuRx or Talent stent-grafts. The primary endpoints of PIVOTAL are aneurysm rupture and AAA-related deaths at up to 36 months after randomization. CAESAR and PIVOTAL should provide objective evidence to guide the use of EVAR for small AAAs.

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

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Screening for AAA in the USA

The United States (U.S.) was home to both the first and the largest reported abdominal aortic aneurysm (AAA) screening programs to date. Influenced by the results of four randomized trials conducted outside the U.S., the U.S. Preventive Services Task Force (USPSTF) recommended one-time AAA screening with ultrasound for men 65–75 years old who have ever smoked. After the USPSTF report, the U.S. Congress added a Medicare benefit for free, one-time AAA screening with ultrasound for men who have smoked and for men and women with a family history of AAA. Screening may be underutilized in this target population, but recommendations by American vascular societies for much broader use of screening and repair than can be justified by the available evidence are influencing practice and threaten the effectiveness and cost-effectiveness of AAA screen ing in the U.S.

Objective risk-scoring systems for repair of abdominal aortic aneurysms: applicability in endovascular repair?

OBJECTIVES

Recent studies propose the use of objective risk-scoring systems as a clinical tool for selecting patients for open or endovascular abdominal aortic aneurysm repair (EVR). The aim of this study was to evaluate four established risk-scoring systems for accuracy of prediction of early mortality and morbidity following EVR.

PATIENTS AND METHODS

266 consecutive patients undergoing elective EVR at St. George's Vascular Institute between July 2001 and January 2007 were studied using a prospective database. The Glasgow Aneurysm Score (GAS), the Vascular Physiology and Operative Severity Score for the enUmeration of Mortality and Morbidity (V-POSSUM), the modified Customised Probability Index (m-CPI) and the Customised Probability Index (CPI) were applied for prediction of 30-day mortality and morbidity. Accuracy of prediction was compared using receiver operating characteristics (ROC) curve analyses.

RESULTS

30-day mortality and morbidity rates were 4% (11/266) and 8% (22/266) respectively. For prediction of mortality, GAS, V-POSSUM, m-CPI and CPI ROC curve analyses showed areas under the curves (AUCs) of 0.68 (95% confidence interval (CI), 0.48-0.87; p=0.046), 0.66 (95% CI, 0.51-0.81; p=0.067), 0.63 (95% CI, 0.45-0.81; p=0.148) and 0.65 (95% CI, 0.49-0.80; p=0.101) respectively. Corresponding AUCs for prediction of morbidity were 0.64 (95% CI, 0.51-0.76; p=0.511), 0.62 (95% CI, 0.51-0.74; p=0.505), 0.54 (95% CI, 0.41-0.67; p=0.416) and 0.55 (95% CI, 0.42-0.68; p=0.451).

CONCLUSIONS

GAS, V-POSSUM, m-CPI and CPI were poor predictors of early mortality and morbidity following EVR in this series. Caution should be applied to the use of these scoring systems for pre-operative risk stratification and treatment selection for endovascular repair of abdominal aneurysms.

Should Endovascular Repair Be Used for Small Abdominal Aortic Aneurysms?

The outcomes of endovascular repair for small abdominal aortic aneurysm (4.0-4.9 cm) is reported. All patients undergoing endovascular abdominal aortic aneurysm repair between 2000 and 2006 with maximal diameter 4.0 to 4.9 cm form the small aneurysm study cohort. Data were analyzed retrospectively and life-table methods were used. Of 743 endovascular repairs, 132 (17.8%) were performed for small abdominal aortic aneurysm. Perioperative complication rate was 9.1%. Freedom from aneurysm expansion was 96% at 1 year, 86% at 3 years, and 77% at 5 years. Overall survival was 98%, 93%, and 84% at 1, 3, and 5 years, respectively. Perioperative 30-day mortality was 0.8% with an aneurysm-related mortality of 1.5% at 5 years. There were no deaths from delayed aneurysm rupture. Endovascular repair of small abdominal aortic aneurysm is associated with low perioperative morbidity and mortality compared with published results for open repair, and treatment threshold can be reduced to 4 cm in selected patients.

Outcome after endografting in small and large abdominal aortic aneurysms: a metanalysis

AIM

To compare the results of endovascular repair (EVAR) in large and small (diameter < 5.5cm) abdominal aortic aneurysms (AAA).

METHODS

A systematic review was performed to identify studies comparing the outcomes after EVAR of large and small aneurysms. Outcomes considered were: risk of death (perioperative, all cause, aneurysm-related), ruptures, and complications (conversion, reintervention). Weighted pooled estimates of outcomes in patients with small versus large aneurysms were calculated. The inverse variance method was used (random-effect model). Subgroup analyses by a follow-up longer or shorter than 24 months were performed.

RESULTS

Five studies, with published and unpublished data, totallying 7,735 patients, were included. Overall, the weighted pooled estimates were: OR 0.68; 95% CI 0.51-0.90 for operative mortality, OR 0.77; 95% CI 0.69 to 0.86 for all cause mortality, OR 0.58; 95% CI 0.40 to 0.87 for aneurysm-related mortality and OR 0.61; 95% CI 0.47 to 0.79 for rupture in favour of small AAA group. Pooled estimates were not influenced by follow-up length. Conversion and reintervention rates were not significantly lower for small AAA.

CONCLUSIONS

EVAR in small versus large AAA might be associated with lower operative mortality, aneurysm-related mortality and aneurysm rupture. Better evidence is needed to support these suggestions.

Factors Affecting Survival after Endovascular Aneurysm Repair: Results from a Population Based Audit

OBJECTIVES

To determine the effect of pre-operative factors on mid-term survival of patients enrolled in an Australian audit of endovascular aneurysm repair (EVAR).

DESIGN

Prospective longitudinal national register (audit) of patients undergoing EVAR.

METHODS

961 individuals who had elective or semi-urgent EVAR of abdominal aortic aneurysms were enrolled in the audit between November 1999 and May 2001. Data was contributed by 81 surgeons from 64 hospitals. Kaplan-Meier survival analysis was used to determine survival rates and factors significantly influencing survival. Parametric survival analysis with log-exponential distribution was used to estimate expected 3 and 5 year survival for different ages, ASA, creatinine and aneurysm sizes.

RESULTS

Overall survival was 93% at 1 year, 80% at 3 years and 67% at five years. Survival rates were found to be statistically associated with ASA, age, aneurysm size and creatinine levels. ASA has the largest effect. Five year survival rates for aneurysms >or=65 mm and <55 mm were 54% and 76% respectively. Pre-operative creatinine levels >or=160 micromol/L lowered the survival rate from 71% to 40%.

CONCLUSIONS

Survival for EVAR patients is strongly correlated with a number of pre-operative factors. This survival analysis provides a useful decision-making tool for surgeons particularly for individuals with smaller aneurysms.