An international, multispecialty, expert-based Delphi Consensus document on controversial issues in the management of patients with asymptomatic and symptomatic carotid stenosis.

OBJECTIVE: Despite the publication of various national/international guidelines, several questions concerning the management of patients with asymptomatic (AsxCS) and symptomatic (SxCS) carotid stenosis remain unanswered. The aim of this international, multi-specialty, expert-based Delphi Consensus document was to address these issues to help clinicians make decisions when guidelines are unclear. METHODS: Fourteen controversial topics were identified. A three-round Delphi Consensus process was performed including 61 experts. The aim of Round 1 was to investigate the differing views and opinions regarding these unresolved topics. In Round 2, clarifications were asked from each participant. In Round 3, the questionnaire was resent to all participants for their final vote. Consensus was reached when ≥75% of experts agreed on a specific response. RESULTS: Most experts agreed that: (1) the current periprocedural/in-hospital stroke/death thresholds for performing a carotid intervention should be lowered from 6% to 4% in patients with SxCS and from 3% to 2% in patients with AsxCS; (2) the time threshold for a patient being considered "recently symptomatic" should be reduced from the current definition of "6 months" to 3 months or less; (3) 80% to 99% AsxCS carries a higher risk of stroke compared with 60% to 79% AsxCS; (4) factors beyond the grade of stenosis and symptoms should be added to the indications for revascularization in AsxCS patients (eg, plaque features of vulnerability and silent infarctions on brain computed tomography scans); and (5) shunting should be used selectively, rather than always or never. Consensus could not be reached on the remaining topics due to conflicting, inadequate, or controversial evidence. CONCLUSIONS: The present international, multi-specialty expert-based Delphi Consensus document attempted to provide responses to several unanswered/unresolved issues. However, consensus could not be achieved on some topics, highlighting areas requiring future research.

The Effect of One Year Aneurysm Sac Dynamics on Five Year Mortality and Continued Aneurysm Sac Evolution.

OBJECTIVE: One year aneurysm sac dynamics after endovascular abdominal aortic aneurysm repair (EVAR) were independently associated with greater risk of all-cause mortality in prior registry studies but were limited in completeness and granularity. This retrospective analysis aimed to study the impact of sac dynamics on survival within the Endurant Stent Graft Global Registry (ENGAGE) with five year follow up. METHODS: A total of 1 263 subjects were enrolled in the ENGAGE Registry between March 2009 and April 2011. One year aneurysm sac changes were calculated from one month post-operative imaging scans and the scan closest to the time of one year follow up. Sac regression was defined as a sac decrease of ≥ 5 mm and sac expansion as aneurysm sac growth ≥ 5 mm. The primary outcome was rate of five year all-cause mortality. Kaplan-Meier estimates for freedom from all-cause mortality were calculated. Multivariable Cox regression was used to determine the association between sac dynamics and all-cause mortality. RESULTS: At one year, 441 of the 949 study participants with appropriate imaging (46%) had abdominal aortic aneurysm sac regression, 462 (49%) remained stable, and 46 (4.8%) had sac expansion. For patients with sac regression, five year all-cause mortality was 20%, compared with 28% for stable sac (p = .007) and 37% for the sac expansion (p = .010) cohorts. After adjustment, sac expansion and stable sac cohorts were associated with greater all-cause mortality (expansion: hazard ratio [HR] 1.8; 95% CI 1.1 - 3.2; p = .032; stable: HR 1.4; 95% CI 1.1 - 1.9; p = .019). CONCLUSION: In the ENGAGE Global Registry, one year rate of sac regression was 46%, and one year sac regression was observed to be associated with greater five year survival, corroborating prior findings utilising data from vascular registries. Sac regression could become the new standard for success after EVAR.

The Fate of Patients Opportunistically Screened for Abdominal Aortic Aneurysms During Echocardiogram or Arterial Duplex Scans.

OBJECTIVE: To evaluate the long term outcomes of individuals who attended for transthoracic echocardiograms (TTEs) or lower limb arterial duplex scans (LLADS) and were opportunistically screened for abdominal aortic aneurysms (AAA). METHODS: Follow up of a prospective single centre pilot cohort study conducted between December 2012 and September 2014 at a tertiary vascular centre in the United Kingdom. Men and Women aged 65 and over were invited to undergo AAA screening when attending hospital for TTE or LLADS. Screening was performed by ultrasonographic examination of the abdomen at the end of their planned scans. AAA was defined as an abdominal aorta outer wall to outer wall anteroposterior diameter of 30 mm or more. Patients were excluded if they had a known AAA or previous abdominal aorta intervention. Follow up outcomes were evaluated in December 2020. RESULTS: 762 patients were enrolled in this study; 486 had TTE and 276 patients had LLADS. The overall incidence of AAA was 54 (7.1%) in the combined cohort, 25 (5.1%) in the TTE group, and 29 (10.5%) in the LLADS group. After a median 7.6 years, two of the 54 AAAs received intervention in the form of endovascular repair. Three others reached treatment threshold but were managed conservatively. The overall intervention rate was 3.7% of detected AAAs. Adjusted mortality rates in those with AAA vs. without was 64.8% and 36%, respectively (hazard ratio [HR] 2.02, p < .001). Diabetes (HR 1.35, p = .015) and older age (HR 1.18, p = .17) were the other factors associated with death. CONCLUSION: AAA is associated with a significantly increased mortality rate. Populations attending hospital for TTE or LLADS demonstrate a higher prevalence of AAA than population based screening; however, the proportion offered AAA intervention was low. Further research into opportunistic screening should target those more likely to undergo AAA repair, unless other interventions are demonstrated, to reduce the general increased mortality in AAA patients.

Predicting Prosthetic Mobility at Discharge From Rehabilitation Following Major Amputation in Vascular Surgery.

OBJECTIVE: This study aimed to construct a decision aid to estimate the likelihood of independence with a prosthesis following rehabilitation for limb loss secondary to advanced ischaemia (acute or chronic limb threatening ischaemia) or diabetic foot disease (DFD). A secondary aim was to determine whether prosthetic independence is a surrogate marker of long term survival. METHODS: A retrospective cohort study of a prospectively maintained database of unilateral amputations due to ischaemia or DFD entering rehabilitation between 2007 and 2020 was performed. Predictors of independent prosthetic mobility (IPM) were used in construction of the IPM prediction model, which underwent bootstrap internal and criterion validation through correlation with predictors of other measures of function: Timed Up and Go (TUG) and two minute walk test. Kaplan-Meier and Cox regression analyses were performed to address the secondary aim. RESULTS: Of the 771 patients included, only 49.9% of amputees achieved IPM. Independent negative predictors of IPM were age > 75 years, female sex, higher amputation level, active malignancy, cerebrovascular disease, end stage renal disease, and cognitive impairment. The model yielded high discrimination (C statistic 0.778), and internal validation was demonstrated with bootstrapping (C statistic 0.778), confirming no over optimism. There was a strong correlation between IPM, TUG, and two minute distance and their predictors, confirming strong criterion validity. The IPM group had a median survival of 93.7 (80.7, 105) months, whereas the non-IPM group fared worse with a median survival of 56.6 (48.5, 66.7) months (p < .001). CONCLUSION: An internally validated decision aid for estimating the likelihood of independence with a prosthesis after major amputation was constructed. A strong association between female sex and poorer prosthetic mobility was observed. Prosthetic function was shown to be a surrogate marker of long term survival. Future research will involve external validation studies to confirm the generalisability of the decision aid in clinical practice.

Association between statin-use and mobility and long-term survival after major lower limb amputation.

AIM: The aim of this study was to determine if there is an association between statin-use and prosthetic mobility and long-term survival in patients receiving rehabilitation after major amputation for lower limb arterial disease. METHODS: A retrospective analysis of prospectively maintained data (2008-2020) from a centre for rehabilitation was performed. Patients were grouped by statin-use status and sub-grouped by the combination of statin and antithrombotic drugs (antiplatelets or anticoagulants). Outcomes were prosthetic mobility (SIGAM score, timed-up-go and 2-min walking distance) and long-term survival. Regression, Kaplan-Meier and Cox-proportional hazard analyses were performed to test associations adjusted to confounders. RESULTS: Of 771 patients, 499 (64.7%) were on a statin before amputation or prescribed a statin peri-operatively. Rate of statin-use was significantly lower among female (53.3%) compared to male (68.2%) patients, P < 0.001. Statin-use was associated with significantly better prosthetic independence (53.1% vs 44.1%, P = 0.017), timed-up-go (mean difference of 4 s, P = 0.04) and long-term survival HR 0.59 (0.48-0.72, P < 0.001). Significance persisted after adjusting for confounding factors and in subgroup analyses. The combination of statin with antiplatelet was associated with the most superior survival, HR 0.51 (0.40-0.65, P < 0.001). Sensitivity analysis (exclusion of non-users of prosthesis) showed that statin-use remained a significant indicator of longer survival, maximally when combined with antiplatelet use HR 0.52 (0.39-0.68, P < 0.001). CONCLUSIONS: Statin-use is associated with better mobility and long-term survival in rehabilitees after limb loss, particularly when used in combination with antiplatelets. Significantly lower rates of statin-use were observed in female patients. Further research is warranted on gender disparities in statin-use and causality in their association with improved mobility and survival.

Optimal Management of Asymptomatic Carotid Stenosis in 2021: The Jury is Still Out. An International, Multispecialty, Expert Review and Position Statement.

OBJECTIVES: The recommendations of international guidelines for the management of asymptomatic carotid stenosis (ACS) often vary considerably and extend from a conservative approach with risk factor modification and best medical treatment (BMT) alone, to a more aggressive approach with a carotid intervention plus BMT. The aim of the current multispecialty position statement is to reconcile the conflicting views on the topic. MATERIALS AND METHODS: A literature review was performed with a focus on data from recent studies. RESULTS: Several clinical and imaging high-risk features have been identified that are associated with an increased long-term ipsilateral ischemic stroke risk in patients with ACS. Such high-risk clinical/imaging features include intraplaque hemorrhage, impaired cerebrovascular reserve, carotid plaque echolucency/ulceration/ neovascularization, a lipid-rich necrotic core, a thin or ruptured fibrous cap, silent brain infarction, a contralateral transient ischemic attack/stroke episode, male patients < 75 years and microembolic signals on transcranial Doppler. There is growing evidence that 80-99% ACS indicate a higher stroke risk than 50-79% stenoses. CONCLUSIONS: Although aggressive risk factor control and BMT should be implemented in all ACS patients, several high-risk features that may increase the risk of a future cerebrovascular event are now documented. Consequently, some guidelines recommend a prophylactic carotid intervention in high-risk patients to prevent future cerebrovascular events. Until the results of the much-anticipated randomized controlled trials emerge, the jury is still out regarding the optimal management of ACS patients.

Migration and sac expansion as modes of midterm therapeutic failure after endovascular aneurysm sealing.

BACKGROUND: Endovascular aneurysm sealing (EVAS) is a disruptive technology to treat abdominal aortic aneurysm (AAA). The use of sac filling rather than endograft fixation was designed to treat aortic aneurysms in a wide range of morphologic appearances and to reduce endoleaks. There are few data reporting outcomes beyond postoperative follow-up. This study reports outcomes up to 5 years for Nellix (Endologix, Irvine, Calif) EVAS. METHODS: Data were prospectively collected for EVAS patients from the time of adoption of EVAS in 2013. All patients treated with the Nellix device are included in this study, and as such, it reports on infrarenal, ruptured, and iliac aneurysms as well as the Nellix-in-Nellix application. Juxtarenal and suprarenal aneurysms were treated using the EVAS system with parallel grafts into the visceral vessels and are included. Therapeutic failure, a composite outcome of migration, sac expansion >5 mm, type Ia and type Ib endoleak, and secondary aortic rupture, was the primary outcome along with all-cause mortality, aneurysm-related mortality, and reintervention rates. RESULTS: There were 295 EVAS cases undertaken between March 2013 and July 2018. Indications for treatment were infrarenal (n = 185), juxtarenal and suprarenal (n = 73), ruptured (n = 18), and iliac (n = 13) aneurysms. There were 15 reinterventions using the Nellix-in-Nellix application. In some cases, EVAS was used to salvage failing endovascular or open aneurysm repairs. Median follow-up was 2.42 years (interquartile range, 1.07-3.57 years). Therapeutic failure was observed in 98 of the 295 cases (33.2%) overall and exceeded 50% in some subgroups. In 71 cases (24.1%), reintervention was performed, with reasons for no reintervention being mainly physiologic. Complications leading to therapeutic failure were most commonly seen beyond 2 years of follow-up. There were 15 secondary ruptures (5.36%), and 9 EVAS devices required explantation either electively or for aortic rupture. CONCLUSIONS: EVAS with the Nellix device has not met expectations, and early encouraging results have been eroded. The incidence of therapeutic failure has been high, occurring 2 years and beyond after implantation. The Nellix system has been voluntarily recalled by Endologix, and the CE mark has subsequently been suspended. The adoption of EVAS as a disruptive technology highlights the need for cautious adoption of novel technologies and the strict governance around such arrangements.

Improving 1-Year Outcomes of Infrainguinal Limb Revascularization: Population-Based Cohort Study of 104 000 Patients in England.

BACKGROUND: The availability and diversity of lower limb revascularization procedures have increased in England in the past decade. We investigated whether these developments in care have translated to improvements in patient pathways and outcomes. METHODS: Individual-patient records from Hospital Episode Statistics were used to identify 103 934 patients who underwent endovascular (angioplasty) or surgical (endarterectomy, profundaplasty, or bypass) lower limb revascularization for infrainguinal peripheral artery disease in England between January 2006 and December 2015. Major lower limb amputations and deaths within 1 year after revascularization were ascertained from Hospital Episode Statistics and Office for National Statistics mortality records. Competing risks regression was used to estimate the cumulative incidence of major amputation and death, adjusted for patient age, sex, comorbidity score, indication for the intervention (intermittent claudication, severe limb ischemia without record of tissue loss, severe limb ischemia with a record of ulceration, severe limb ischemia with a record of gangrene/osteomyelitis), and comorbid diabetes mellitus. RESULTS: The estimated 1-year risk of major amputation decreased from 5.7% (in 2006-2007) to 3.9% (in 2014-2015) following endovascular revascularization, and from 11.2% (2006-2007) to 6.6% (2014-2015) following surgical procedures. The risk of death after both types of revascularization also decreased. These trends were observed for all indication categories, with the largest reductions found in patients with severe limb ischemia with ulceration or gangrene. Overall, morbidity increased over the study period, and a larger proportion of patients was treated for the severe end of the peripheral artery disease spectrum using less invasive procedures. CONCLUSIONS: Our findings show that from 2006 to 2015, the overall survival increased and the risk of major lower limb amputation decreased following revascularization. These observations suggest that patient outcomes after lower limb revascularization have improved during a period of centralization and specialization of vascular services in the United Kingdom.

Changing Patterns of Carotid Endarterectomy Between 2011 and 2017 in England.

Background and Purpose- Carotid endarterectomy (CEA) reduces the risk of stroke in recently symptomatic patients and less so in asymptomatic patients. Recent evidence suggests that the number of CEAs may be declining. The aim of this study was to investigate annual patterns of CEA in asymptomatic and symptomatic patients in England from 2011 to 2017. Methods- Data from the National Vascular Registry were used to describe (1) the number of CEA procedures in England and its 9 geographic regions from 2011 to 2017, (2) the characteristics of patients undergoing CEA, and (3) whether rates of CEA correlated with the number of vascular arterial units within each region. Annual stroke incidence for each region was derived from official population figures and the number of index stroke admissions per year. Results- The overall number of CEAs performed in England fell from 4992 in 2011 to 3482 in 2017, a 30% decline. Among symptomatic patients, there was a 25% decline, the number of CEAs falling from 4270 to 3217. In asymptomatic patients, there were 722 CEAs performed in 2011 and 265 in 2017, a 63% decline. CEAs per 100 000 adults within all regions declined over time but the size of change varied across the regions (range, 1.7-5.5 per 100 000). The regional numbers of CEAs per year were associated with changes in the regional stroke incidence, the proportion of CEAs performed in asymptomatic patients, and the number of hospitals performing CEA. Conclusions- This population-based study revealed a 63% decline in CEAs among asymptomatic patients between 2011 and 2017, possibly because of changing attitudes in the role of CEA. Reasons for the 25% decline in CEAs among symptomatic patients are unclear as UK guidelines on CEA have not changed for these patients. Whether the proportion of symptomatic patients with 50% to 99% ipsilateral stenosis has changed requires investigation.

Thresholds for Abdominal Aortic Aneurysm Repair in England and the United States.

BACKGROUND: Thresholds for repair of abdominal aortic aneurysms vary considerably among countries. METHODS: We examined differences between England and the United States in the frequency of aneurysm repair, the mean aneurysm diameter at the time of the procedure, and rates of aneurysm rupture and aneurysm-related death. Data on the frequency of repair of intact (nonruptured) abdominal aortic aneurysms, in-hospital mortality among patients who had undergone aneurysm repair, and rates of aneurysm rupture during the period from 2005 through 2012 were extracted from the Hospital Episode Statistics database in England and the U.S. Nationwide Inpatient Sample. Data on the aneurysm diameter at the time of repair were extracted from the U.K. National Vascular Registry (2014 data) and from the U.S. National Surgical Quality Improvement Program (2013 data). Aneurysm-related mortality during the period from 2005 through 2012 was determined from data obtained from the Centers for Disease Control and Prevention and the U.K. Office of National Statistics. Data were adjusted with the use of direct standardization or conditional logistic regression for differences between England and the United States with respect to population age and sex. RESULTS: During the period from 2005 through 2012, a total of 29,300 patients in England and 278,921 patients in the United States underwent repair of intact abdominal aortic aneurysms. Aneurysm repair was less common in England than in the United States (odds ratio, 0.49; 95% confidence interval [CI], 0.48 to 0.49; P<0.001), and aneurysm-related death was more common in England than in the United States (odds ratio, 3.60; 95% CI, 3.55 to 3.64; P<0.001). Hospitalization due to an aneurysm rupture occurred more frequently in England than in the United States (odds ratio, 2.23; 95% CI, 2.19 to 2.27; P<0.001), and the mean aneurysm diameter at the time of repair was larger in England (63.7 mm vs. 58.3 mm, P<0.001). CONCLUSIONS: We found a lower rate of repair of abdominal aortic aneurysms and a larger mean aneurysm diameter at the time of repair in England than in the United States and lower rates of aneurysm rupture and aneurysm-related death in the United States than in England. (Funded by the Circulation Foundation and others.).

Short Stay EVAR is Safe and Cost Effective.

OBJECTIVE: Reducing length of stay (LOS) following surgery offers the potential to improve resource utilisation. Endovascular aneurysm repair (EVAR) is now delivered with a low level of morbidity and as such may be deliverable as a "23 hour stay" intervention. This systematic review aims to assess safety, feasibility and cost effectiveness of a short stay EVAR pathway. METHODS: A database search of Ovid MEDLINE (1996 - April 2018) and Embase (1974 - April 2018) was completed. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used. A Newcastle-Ottawa Scale was applied to assess study bias. RESULTS: In total, 570 papers were identified through the literature search, of which 32 abstracts were screened. This led to nine papers being assessed for eligibility. From five suitable studies, 450 (75%) patients were successfully discharged the same or next day after EVAR. Complications most often occurred within 3 hours of surgery, and major complications requiring intensive treatment unit admission occurred within 6 hours. Readmission rates were 0-5% for those discharged early, with no difference in 30 day readmission. Early discharge led to a statistically significant cost saving of £13,360 (LOS four days) to £9844 (LOS one day). CONCLUSION: Selected patients can safely undergo EVAR using a short stay pathway. A period of monitoring 6 h post-operatively for low risk patients would be sufficient. Reducing length of stay after EVAR in the UK from the current median of three days to 1.5 days would free 4361 bed days and lead to a saving of approximately £1,800,000 annually.

Cerebral embolization during endovascular infrarenal, juxtarenal, and suprarenal aortic aneurysm repair, high-risk maneuvers, and associated neurologic outcomes.

BACKGROUND: Risk factors for postoperative cognitive decline after noncardiac surgery are multifactorial and poorly understood. Evidence suggests that perioperative microembolic damage to the brain on movement of wires and catheters during endovascular aortic procedures may play an important role. Endovascular aortic aneurysm repair requires invasive manipulation of wires and cannulas within the aorta, but research into cerebral emboli during aortic aneurysm repair and cognitive or neurologic injury is scarce and limited to thoracic aneurysms. This study prospectively studied embolic phenomena detected in the middle cerebral artery during infrarenal, juxtarenal, and thoracic endovascular aortic repair (TEVAR) and investigated links to delirium, stroke, and postoperative cognitive decline. METHODS: There were 60 patients who received continuous left-sided perioperative transcranial Doppler monitoring during endovascular aortic aneurysm repair (bifurcated graft for infrarenal aneurysm, n = 18; endovascular aneurysm sealing graft, n = 16; endovascular aneurysm sealing and renal "chimney" stent, n = 17; and thoracic aneurysm, n = 3). The procedure was time stamped for events such as stiff wire insertion and graft deployment. A battery of cognitive tests designed to test several cognitive domains were performed preoperatively and at 90 days postoperatively. RESULTS: TEVAR and chimney grafts demonstrated significantly greater numbers of total procedural emboli compared with standard bifurcated grafts (mean emboli, 36.2 and 13.39, respectively; bifurcated graft, 5.81; P < .05). The highest risk maneuvers were guidewire and pigtail catheter insertion. This was the case for all procedures including infrarenal aneurysm repair. A higher perioperative embolic load was associated with medium-term cognitive decline in list recall but not with incidence of delirium or stroke. Risk of cognitive decline did not relate to procedure type. Antiplatelet use failed to demonstrate a protective effect. CONCLUSIONS: Patients are at risk of cerebral emboli during several types of endovascular aortic surgery, although TEVAR remains the highest risk procedure. As yet, there are no validated protective measures available to prevent cerebral emboli and their associated risks of clinical and subclinical neurologic injury.

Screening results from a large United Kingdom abdominal aortic aneurysm screening center in the context of optimizing United Kingdom National Abdominal Aortic Aneurysm Screening Programme protocols.

BACKGROUND: After its introduction in six pilot centers in 2009, the National Abdominal Aortic Aneurysm Screening Programme (NAAASP) is now established across the United Kingdom, demonstrating significant benefit in terms of fewer emergency surgeries and reduced 30-day surgical mortality. However, according to publication of data on annual screened abdominal aortic aneurysm (AAA) detection, a lower incidence than predicted in the original screening trials has been found. In this audit we assessed features and risk factors of men found to have a positive scan result in the southwest London AAA screening program, to determine screening yield for subgroups of populations and assess the case for a more targeted screening program. METHODS: Data from the NAAASP screening database for England were extracted for all men who attended screening from the April 1, 2009 through October 16, 2013 in the southwest London area. Primary outcomes were aneurysm prevalence, risk factors, and incidence within subgroups. Results were reviewed against nationally reported data and London census data. RESULTS: Of 24,891 men who were screened in the southwest London program during this period, 292 AAAs were identified (1.18%). Patients were asked to categorize their ethnic background according to classifications provided by the office of national statistics. Those at highest risk of AAA were white-British (1.35%), followed by black and black British (0.65%), and Asian/Asian British (0.23%). Number needed to screen to identify one AAA was calculated as 78, 154, and 431, respectively. The relative proportions of patients screened were similar to that described in the most recent United Kingdom census, except for white-British patients, indicating a shortfall in acceptance of screening invitations in this group. There were no AAA identified in Chinese men. A positive smoking history was found in 90%, a confirmed diagnosis of hypertension in 50%, hypercholesterolemia in 34%, and ischemic heart disease in 21%. CONCLUSIONS: Within southwest London, AAA was most strongly associated with being white-British, a previous or current smoker, and known hypertension. Targeted education in patient groups with identified risk factors for AAA should be considered to improve screening yield without excluding any subgroup from the screening program. This could draw on resources released by unused scans because of lower than predicted prevalence. AAA diagnosis should be seen as an opportunity to address the increased all-cause mortality associated with aortic aneurysmal disease.

The Abdominal Aortic Aneurysm Statistically Corrected Operative Risk Evaluation (AAA SCORE) for predicting mortality after open and endovascular interventions.

BACKGROUND: Accurate adjustment of surgical outcome data for risk is vital in an era of surgeon-level reporting. Current risk prediction models for abdominal aortic aneurysm (AAA) repair are suboptimal. We aimed to develop a reliable risk model for in-hospital mortality after intervention for AAA, using rigorous contemporary statistical techniques to handle missing data. METHODS: Using data collected during a 15-month period in the United Kingdom National Vascular Database, we applied multiple imputation methodology together with stepwise model selection to generate preoperative and perioperative models of in-hospital mortality after AAA repair, using two thirds of the available data. Model performance was then assessed on the remaining third of the data by receiver operating characteristic curve analysis and compared with existing risk prediction models. Model calibration was assessed by Hosmer-Lemeshow analysis. RESULTS: A total of 8088 AAA repair operations were recorded in the National Vascular Database during the study period, of which 5870 (72.6%) were elective procedures. Both preoperative and perioperative models showed excellent discrimination, with areas under the receiver operating characteristic curve of .89 and .92, respectively. This was significantly better than any of the existing models (area under the receiver operating characteristic curve for best comparator model, .84 and .88; P < .001 and P = .001, respectively). Discrimination remained excellent when only elective procedures were considered. There was no evidence of miscalibration by Hosmer-Lemeshow analysis. CONCLUSIONS: We have developed accurate models to assess risk of in-hospital mortality after AAA repair. These models were carefully developed with rigorous statistical methodology and significantly outperform existing methods for both elective cases and overall AAA mortality. These models will be invaluable for both preoperative patient counseling and accurate risk adjustment of published outcome data.

Management of a type Ia endoleak with the Nellix endovascular aneurysm sealing system.

PURPOSE: To report the application of the Nellix endovascular aneurysm sealing (EVAS) device, including two chimney grafts, to successfully treat a type Ia endoleak. CASE REPORT: An 87-year-old man had an asymptomatic 7.6-cm infrarenal abdominal aortic aneurysm (AAA) and a 4.5-cm right internal iliac artery aneurysm treated using an aortouni-iliac stent-graft. Two years after the index endovascular repair, an asymptomatic type Ia endoleak was detected on duplex ultrasound; the computed tomographic angiogram (CTA) demonstrated significant sac enlargement and stent-graft migration. Initial attempts to treat the leak with 2 aortic cuffs only reduced the size of the endoleak. Another procedure was undertaken using the Nellix device with chimney grafts to increase the proximal sealing zone above the existing stent-graft. Imaging postoperatively demonstrated successful resolution of the endoleak and continuing patency of both renal artery chimney stent-grafts. CTA at 6 months demonstrated persistent sealing of the endoleak. CONCLUSION: The use of the EVAS system may represent another endovascular solution that can be added to the clinician's repertoire for treating type Ia endoleak after conventional endovascular repair of infrarenal AAA.