Variations in Abdominal Aortic Aneurysm Care: A Report From the International Consortium of Vascular Registries

Five-year survival after elective open and endovascular aortic aneurysm repair

BACKGROUND AND OBJECTIVE

Current evidence suggests short-term survival benefit from endovascular aneurysm repair (EVAR) versus open surgical repair (OSR) in elective abdominal aortic aneurysm (AAA) procedures, but this benefit is lost during long-term follow-up. The aim of this study was to compare short- and mid-term all-cause mortality in patients with non-ruptured aneurysm treated by OSR and EVAR; and to assess the rate of complications and reinterventions, as well as to evaluate their impact on survival.

METHODS

The medical records of the non-ruptured AAA patients undergoing OSR or EVAR between 1 January 2011 and 31 December 2019 at Tartu University Hospital, Estonia, were retrospectively reviewed. We gathered survival data from the national registry (mean follow-up period was 3.7 ± 2.3 years).

RESULTS

A total of 225 non-ruptured AAA patients were treated operatively out of whom 95 (42.2%) were EVAR and 130 (57.8%) were OSR procedures. The difference in estimated all-cause mortality between the OSR and EVAR groups at day 30 was statistically irrelevant (2.3% vs 0%; p = 0.140), but OSR patients showed statistically significantly higher 5 year survival compared with EVAR patients (75.3% vs 50.0%, p = 0.002). Complication and reintervention rates for the EVAR and OSR groups did not differ statistically (26.3% vs 16.9%, p = 0.122; 10.5% vs 11.5%, p = 0.981, respectively). Multivariate analysis revealed that greater aneurysm diameter (p = 0.012), EVAR procedure (p = 0.016), male gender (p = 0.023), and cerebrovascular diseases (p = 0.028) were independently positively associated with 5-year mortality.

CONCLUSIONS

Thirty-day mortality, and complication and reintervention rates for EVAR and OSR after elective AAA repair were similar. Although the EVAR procedure is an independent risk factor for 5-year mortality, higher age and greater proportion of comorbidities among EVAR patients may influence not only the choice of treatment modality, but also prognosis.

Long-term implications of elective evar that is non-compliant with clinical practice guideline diameter thresholds

OBJECTIVE

Compliance with Society for Vascular Surgery (SVS) abdominal aortic aneurysm (AAA) clinical practice guideline (CPG)-diameter thresholds is variable for endovascular aneurysm repair (EVAR). To evaluate the implications and appropriateness of repairs that are noncompliant with current guidelines, we investigated the long-term outcomes, adherence to imaging follow-up, and associated health care costs in patients undergoing EVAR for AAA who do or do not meet recommended diameter thresholds.

METHODS

All patients receiving elective EVAR from 2003 to 2016 in the SVS Vascular Quality Initiative with linked Medicare claims were reviewed. Weekend procedures and isolated iliac aneurysms, as well as symptomatic and ruptured presentations, were excluded. Diameter thresholds for noncompliant repairs were defined as: men <55 mm; women <50 mm who did not have an iliac diameter ≥30 mm. We evaluated adherence to postoperative imaging surveillance, reimbursement amounts, reintervention, rupture, and all-cause mortality. We defined an EVAR quality metric as performance of the index procedure with freedom from conversion to open repair, 5-year rupture-free survival, and adherence to minimum imaging surveillance (at least one computed tomography scan documented between 6 and 24 months postoperatively).

RESULTS

Among 19,018 elective EVARs, 35% did not meet CPG diameter thresholds (26% within 5 mm of threshold). The rate of noncompliant repairs increased over time (24% in 2003 vs 36% in 2016; P < .001). Patients undergoing noncompliant repairs were younger, less likely to have multiple comorbidities, and more likely to receive EVAR with adherence to instructions for use criteria (89% vs 79%; P < .001). Patients undergoing noncompliant repairs had greater 5-year freedom from reintervention (86% vs 81%; P < .001), rupture-free survival (94% vs 92%; P = .01), and overall survival rates (71% vs 61%; P < .001) compared with repairs that complied with CPG diameter thresholds. Although noncompliant repairs had higher rates of 1-year imaging surveillance, overall differences were modest (68% vs 65%; P = .003). Importantly, for the entire cohort, follow-up imaging surveillance decreased over time (93% in 2003 vs 63% in 2014; P < .001). Notably, although noncompliant repairs had higher rates of achieving the composite quality metric compared with compliant repairs (43% vs 38%; P < .001), failure occurred with a significant majority of all repairs.

CONCLUSIONS

Compliance with SVS-endorsed CPG diameter thresholds for elective EVAR is poor, and rates of noncompliance are increasing. Noncompliant repairs appear to be offered more commonly to patients with fewer comorbidities and favorable anatomy, and these repairs are associated with improved rates of reintervention, rupture, and survival compared with procedures meeting CPG diameter thresholds. Importantly, noncompliant repairs fail to meet minimum quality standards in a majority of cases, which underscores the need for further policies to improve the overall quality and appropriateness of AAA care delivery nationally.

Thresholds for abdominal aortic aneurysm repair in Canada and United States

BACKGROUND

Previous studies have demonstrated significant geographic variations in the management of abdominal aortic aneurysms (AAA) despite standard guidelines. Differences in patient selection, operative technique, and outcomes for AAA repair in Canada versus United States were assessed.

METHODS

The Vascular Quality Initiative was used to identify all patients who underwent elective endovascular or open AAA repair between 2010 and 2019 in Canada and the United States. Demographic, clinical, and procedural characteristics were recorded and differences between countries were assessed using independent t test and χ² test. The primary outcome was the percentage of AAA repaired below recommended diameter thresholds (men, <5.5 cm; women, <5.0 cm). The secondary outcomes were in-hospital and 1-year mortality rates. Associations between region and outcomes were assessed using univariate/multivariate logistic regression and Cox proportional hazards analysis.

RESULTS

There were 51,455 US patients and 1451 Canadian patients who underwent AAA repair in Vascular Quality Initiative sites during the study period. There was a higher proportion of endovascular repairs in the United States (83.7% vs 68.4%; odds ratio [OR], 2.38; 95% confidence interval [CI], 2.13-2.63; P < .001). US patients had more comorbidities, including hypertension, congestive heart failure, chronic kidney disease, and prior revascularization. The percentage of AAA repaired below recommended thresholds was significantly higher in the United States (38.8% vs 15.2%; OR, 3.57; 95% CI, 3.03-4.17; P < .001). This difference persisted after controlling for demographic, clinical, and procedural characteristics (adjusted OR, 3.57; 95% CI, 2.63-4.17; P < .001). Factors that predicted AAA repair below recommended thresholds were US region (adjusted OR, 3.57; 95% CI, 3.03-4.17), male sex (adjusted OR, 2.89; 95% CI, 2.72-3.07), and endovascular repair (adjusted OR, 2.08; 95% CI, 1.95-2.21). The in-hospital mortality rate was low (1.0% vs 0.8%) and the 1-year rate mortality was similar between countries (hazard ratio, 0.96; 95% CI, 0.70-1.31; P = .79).

CONCLUSIONS

There are significant variations in AAA management between Canada and the United States. A greater proportion of US patients underwent AAA repair below the recommended diameter thresholds. This finding is partly driven by a higher percentage of endovascular repairs. Despite these differences, the perioperative and 1-year mortality rates are similar. Future studies should investigate reasons for these variations and quality improvement projects are needed to standardize care.

Nationwide Study of Ruptured Abdominal Aortic Aneurysms During Twenty Years (1994-2013)

OBJECTIVE

To analyze the epidemiology of ruptured abdominal aortic aneurysms (RAAA) in Sweden over 20 years, and assess the effect of endovascular repair (EVAR) on surgical treatment rate and outcome.

METHODS

All Swedish citizens >50 years with RAAA 1994 to 2013 were extracted from 3 national (Cause of Death, Patient, and Vascular Surgical) registries. Incidence, proportion repaired, surgical techniques, and 90-day mortality were assessed based on sex and age groups, with regression analysis.

RESULTS

18,726 individuals with RAAA were identified, 74.0% men. The incidence of RAAA decreased from 33.1/100,000: 1994 to 21.3/100,000: 2013 (relative change -35.6%, P < 0.001). The proportion of men with RAAA undergoing repair was 44.5%: 1994-1998, 49.7%: 2009-2013 (+11.7%, P < 0.001). In women, 22.3% were repaired in 1994-1998, versus 28.2%: 2009-2013 (+26.4%, P < 0.001). The proportion undergoing repair increased in octogenarians (men: +44.3%, P < 0.001; women +49.3%, P = 0.001). EVAR increased from 0% initially to 42.3% in men and 41.2% in women 2013. Overall, mortality rate among all individuals with RAAA decreased, men 75.8%: 1994-1998, 64.8%: 2009-2013 (-14.5%, P < 0.001); women 88.5%: 1994-1998, 82.2%: 2009-2013 (-7.1%, P < 0.001). Among those who underwent repair, mortality was 47.0% in men: 1994-1998, 31.8%: 2009-2013 (-32.3%, P < 0.001); women 51.8%: 1994-1998, 41.4%: 2009-2013 (-20.1%, P = 0.010).

CONCLUSION

RAAA mortality among men decreased, mainly attributed to falling incidence of RAAA. The mortality was further reduced by more patients being offered repair, increasingly often with EVAR, and improved survival after repair. Incidence of rupture remained unchanged among women, who had higher RAAA mortality. Focused efforts to reduce RAAA mortality among women are warranted.

Association between Hospital Volume and Failure to Rescue after Open or Endovascular Repair of Intact Abdominal Aortic Aneurysms in the VASCUNET and International Consortium of Vascular Registries

OBJECTIVE

To investigate the association between hospital volume and failure to rescue (FtR), after open (OAR) and endovascular (EVAR) repair of intact abdominal aortic aneurysms (AAA) among centers participating in the VASCUNET and International Consortium of Vascular Registries (ICVR).

SUMMARY BACKGROUND DATA

FtR (i.e., in-hospital death following major complications) is a composite end-point representing the inability to treat complications effectively and prevent death.

METHODS

Using data from eight vascular registries, complication and mortality rates after intact AAA repair were examined (n = 60,273; EVAR-43,668; OAR-16,605). A restricted analysis using pooled data from four countries (Australia, Hungary, New Zealand, USA) reporting data on all postoperative complications (bleeding, stroke, cardiac, respiratory, renal, colonic ischemia) was performed to identify risk-adjusted association between hospital volume and FtR.

RESULTS

The most frequently reported complications were cardiac (EVAR-3.0%, OAR-8.9%) and respiratory (EVAR-1.0%, OAR-5.7%). In adjusted analysis, 4.3% of EVARs and 18.5% of OARs had at least one complication. The overall FtR rate was 10.3% after EVAR and 15.7% after OAR. Subjects treated in the highest volume centers(Q4) had 46% and 80% lower odds of FtR after EVAR (OR = 0.54; 95%CI = 0.34-0.87;p = 0.04) and OAR (OR = 0.22; 95%CI = 0.11-0.44;p < 0.001) when compared to lowest volume centers(Q1), respectively. Colonic ischemia had the highest risk of FtR for both procedures (adjusted predicted risks, EVAR: 27%, 95%CI 14%-45%; OAR: 30%, 95%CI 17%-46%).

CONCLUSIONS

In this multi-national dataset, FtR rate after intact AAA repair with EVAR and OAR is significantly associated with hospital volume. Hospitals in the top volume quartiles achieve the lowest mortality after a complication has occurred.

Long-term Reintervention After Endovascular Abdominal Aortic Aneurysm Repair

OBJECTIVE

To describe the long-term reintervention rate after endovascular abdominal aortic aneurysm repair (EVR), and identify factors predicting reintervention.

SUMMARY OF BACKGROUND DATA

EVR is the most common method of aneurysm repair in America, and reintervention after EVR is common. Clinical factors predicting reintervention have not been described in large datasets with long-term follow-up.

METHODS

We studied patients who underwent EVR using the Vascular Quality Initiative registry linked to Medicare claims. Our primary outcome was reintervention, defined as any procedure related to the EVR after discharge from the index hospitalization. We used classification and regression tree modeling to inform a multivariable Cox-regression model predicting reintervention after EVR.

RESULTS

We studied 12,911 patients treated from 2003 to 2015. Mean age was 75.5 ± 7.3 years, 79.9% were male, and 89.1% of operations were elective. The 3-year reintervention rate was 15%, and the 10-year rate was 33%. Five factors predicted reintervention: operative time ≥3.0 hours, aneurysm diameter ≥6.0 cm, an iliac artery aneurysm ≥2.0 cm, emergency surgery, and a history of prior aortic surgery. Patients with no risk factors had a 3-year reintervention rate of 12%, and 10-year rate of 26% (n = 7310). Patients with multiple risk factors, such as prior aortic surgery and emergent surgery, had a 3-year reintervention rate 72%, (n = 32). Modifiable factors including EVR graft manufacturer or supra-renal fixation were not associated with reintervention (P = 0.76 and 0.79 respectively).

CONCLUSIONS

All patients retain a high likelihood of reintervention after EVR, but clinical factors at the time of repair can predict those at highest risk.

Editor's Choice - Variation in Intact Abdominal Aortic Aneurysm Repair Outcomes by Country: Analysis of International Consortium of Vascular Registries 2010 - 2016

OBJECTIVE

Outcomes for intact abdominal aortic aneurysm (AAA) repair vary over time and by healthcare system, country, and surgeon. The aim of this study was to analyse peri-operative mortality for intact AAA repair in 11 countries over time and compare outcomes by gender, age, and geographical location.

METHODS

Prospective data on primary repair of intact AAA were collected from 11 countries through the International Consortium of Vascular Registries (ICVR) and analysed for two time periods, 2010 - 2013 and 2014 - 2016. The primary outcome was peri-operative mortality after endovascular aneurysm repair (EVAR) and open surgical repair (OSR). Multivariable logistic regression models were used to adjust for differences in patient characteristics.

RESULTS

A total of 103 715 patients were included. The percentage of patients undergoing EVAR increased from 63.6% to 71.2% (p < .001) over the study period. This proportion varied by country from 35% in Hungary to 81% in the United States. Overall peri-operative mortality decreased from 2.1% to 1.6 % (p < .001). Mortality also declined significantly over time for both OSR 4.2% to 3.6 % (p = .002) and EVAR 1.0% to 0.7% (p = .002). Mortality was significantly higher for female than male patients (3.0% vs. 1.6% p < .001). The percentage of patients > 80 years old undergoing AAA repair remained constant at 23.6% (p = .91). Peri-operative mortality was higher for patients > 80 years than for those < 80 years old (2.7% vs. 1.6% p < .001). Forty-six per cent (n = 275) of all EVAR deaths occurred in the over 80s.

CONCLUSION

The proportion of AAA repairs performed using EVAR has increased over time. Peri-operative mortality continues to decline for both OSR and EVAR. Outcomes however were significantly worse for both women and those aged over 80, so efforts should be focused on these patient groups to further reduce elective AAA mortality rates.

[Treatment reality of aortic diseases in Switzerland]

Background

Due to the federally organized healthcare system in Switzerland, aortic interventions are performed in many different hospitals, presumably sometimes with a very small number of cases per institution. The aim of this study was to present the treatment reality of aortic diseases based on the aortic interventions recorded in Switzerland's vascular registry Swissvasc.

Methods

All interventions on the aorta that were carried out between January 2018 and December 2020 in Switzerland and entered in the Swissvasc registry were included in this overview. Interventions for the treatment of isolated pathologies of the iliac vessels as well as interventions on the ascending aorta and the proximal aortic arch were excluded.

Results

Open aortic surgery was performed in 28 hospitals and endovascular aortic repair (EVAR) in 33. Just under half of these hospitals achieved the recommended minimum number of cases for abdominal aortic aneurysms (AAA) of 30 open and endovascular interventions per year, which are currently discussed in the literature. In line with the literature 67% of the elective treatments for AAA were performed by EVAR. Corresponding to the current literature, 11% of the AAA were ruptured in the 3‑year observation period. In contrast to the recommendations of the current guidelines almost 60% of the ruptured AAA were treated by open repair. There was a certain tendency for a spontaneous centralization in the treatment of thoracic aortic pathologies as 87% of the interventions were carried out in only 5 hospitals.

Conclusion

This study shows that many clinics in Switzerland treat aortic pathologies, some with a very small caseload. Further investigations of the quality of care in the treatment of aortic pathologies are urgently needed.

The impact of COVID-19 pandemic on vascular registries and clinical trials

Quality improvement programs and clinical trial research experienced disruption due to the coronavirus disease 2019 (COVID-19) pandemic. Vascular registries showed an immediate impact with significant declines in second-quarter vascular procedure volumes witnessed across Europe and the United States. To better understand the magnitude and impact of the pandemic, organizations and study groups sent grass roots surveys to vascular specialists for needs assessment. Several vascular registries responded quickly by insertion of COVID-19 variables into their data collection forms. More than 80% of clinical trials have been reported delayed or not started due to factors that included loss of enrollment from patient concerns or mandated institutional shutdowns, weighing the risk of trial participation on patient safety. Preliminary data of patients undergoing vascular surgery with active COVID-19 infection show inferior outcomes (morbidity) and increased mortality. Disease-specific vascular surgery study collaboratives about COVID-19 were created for the desire to study the disease in a more focused manner than possible through registry outcomes. This review describes the pandemic effect on multiple VASCUNET registries including Germany (GermanVasc), Sweden (SwedVasc), United Kingdom (UK National Vascular Registry), Australia and New Zealand (bi-national Australasian Vascular Audit), as well as the United States (Society for Vascular Surgery Vascular Quality Initiative). We will highlight the continued collaboration of VASCUNET with the Vascular Quality Initiative in the International Consortium of Vascular Registries as part of the Medical Device Epidemiology Network coordinated registry network. Vascular registries must remain flexible and responsive to new and future real-world problems affecting vascular patients.

Appropriateness of surgery performed for abdominal aortic aneurysm at tertiary hospitals in Spain

BACKGROUND

To analyze the appropriateness of the type of repair (open or endovascular) performed for abdominal aortic aneurysm (AAA) in five university hospitals in Spain, according to evidence-based recommendations.

METHODS

A multicenter, retrospective cross-sectional study of patients with AAA who underwent elective open surgical repair (OSR) or endovascular aneurysm repair (EVAR). Data were collected on demographic and clinical variables and type of surgical repair. A pair of vascular surgeons from each participating hospital performed a blinded assessment based on GRADE recommendations. The concordance between the two evaluators and the agreement between their evidence-based recommendation and the procedure actually performed were assessed.

RESULTS

A total of 186 patients were selected; 179 were included. Mean age was 72.5 years (standard deviation [SD], 8.4), mean Charlson Comorbidity Index (CCI) was 2.04 (SD, 1.9). OSR was performed in 53.2% (n=99) and EVAR in 46.8% (n=87) of cases. Overall, 65.9% (118/179) of interventions performed were considered appropriate: 50% (47/94) of OSRs and 83.5% (71/85) of EVARs. The patient characteristics were similar for all the hospitals, but the chosen surgical technique did show significant differences among these centers. There were no significant differences among the hospitals in the proportion of cases judged as appropriate, either overall (p=0.346) or for each type of procedure (p=0.531 and p=0.538 for OSR and EVAR, respectively).

CONCLUSIONS

In this study, the majority of the AAA repairs performed were appropriate according to GRADE recommendations. A higher proportion of EVARs were considered appropriate than OSRs. Choice of AAA repair should be standardized through the use of evidence-based clinical practice guidelines, while incorporating patient preferences, to reduce the existing variability and ensure appropriate selection of AAA repair technique.

Anatomic eligibility for endovascular aneurysm repair preserved over 2 years of surveillance

OBJECTIVE

Endovascular aneurysm repair (EVAR) is a widely used option for patients with suitable vascular anatomy who have a large infrarenal abdominal aortic aneurysm (AAA). Patients with small AAAs are managed with careful surveillance and it is a common concern that their anatomy may change with AAA growth, and their option for EVAR may become limited. Device innovation has resulted in expanded ranges of anatomy that may be eligible for EVAR. This study sought to identify changes in anatomic eligibility for repair with contemporary endovascular devices in AAA patients, monitored by computed tomography scan over the course of 2 years.

METHODS

Patients from the Non-Invasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (N-TA³CT, NCT01756833) were included in this analysis. Females had baseline AAA maximum transverse diameter between 3.5 and 4.5 cm, and males had baseline maximum transverse diameter between 3.5 and 5.0 cm. Patients were included in this analysis if they completed pre-enrollment and 2-year follow-up computed tomography imaging. Pertinent anatomic measurements were performed on a postprocessing workstation in a centralized imaging core laboratory. EVAR candidacy was determined by measuring proximal aortic neck diameter, AAA length, and infrarenal neck angulation. Patients were considered to be eligible for EVAR if they qualified for at least one of the seven studied devices' instructions for use at baseline and at 2 years. A paired t test analysis was used to detect differences in aortic measurements over 2 years, and the McNemar test was used to compare eligibility over 2 years.

RESULTS

We included 192 patients in this analysis-168 male and 24 female. Of these patients, 85% were eligible for EVAR at baseline and 85% after 2 years of follow-up (P = 1.00; 95% confidence interval -0.034 to 0.034). Of the 164 EVAR candidates at baseline, 160 (98%) remained eligible over 2 years of surveillance. Insufficient neck length was the most common reason for both ineligibility at baseline (18 of 28 patients) as well as loss of candidacy over 2 years (3 of 4 patients).

CONCLUSIONS

The majority of patients eligible for EVAR when entering a surveillance program for small AAA remain eligible after 2 years. Substantial changes in AAA neck anatomy resulting in loss of EVAR treatment options are infrequent. Patients with anatomic AAA progression beyond EVAR eligibility remain candidates for complex EVAR and open repair.

Endovascular Aortic Repair in Nonagenarian Patients

BACKGROUND

The increasing proportion of elderly patients being treated for abdominal aortic aneurysm (AAA) in the endovascular era is controversial.

OBJECTIVES

This study compared 30-day outcomes of endovascular aortic repair (EVAR) in nonagenarians (NAs) with non-nonagenarians (NNAs).

METHODS

This retrospective analysis of the American College of Surgeons National Surgical Quality Improvement Program database included EVAR procedures performed from 2011 to 2017. Multivariate logistic regression in the unadjusted cohort, followed by propensity-score matching (PSM), was performed. Primary outcomes were 30-day mortality and 30-day major adverse events.

RESULTS

A total of 12,267 patients were included (365 NAs). Ruptured aneurysms accounted for 6.7% (n = 819): 15.7% (n = 57) in NAs versus 6.5% (n = 762) in NNAs (p < 0.001). Mean aneurysm diameter was 6.5 ± 1.8 cm in NAs versus 5.8 ± 1.7 cm in NNAs (p < 0.001). The unadjusted 30-day mortality was 9.9% in NA versus 2.2% in NNAs (p < 0.001). Multivariate analysis revealed age ≥90 years (odds ratio [OR]: 3.36), male sex (OR: 1.78), functional status (OR: 4.22), pre-operative ventilator dependency (OR: 3.80), bleeding disorders (OR: 1.52), dialysis (OR: 2.56), and ruptured aneurysms (OR: 17.21) as independent predictors of mortality. After PSM, no differences in 30-day mortality (intact AAA [iAAA]: 5.3% NA vs. 3% NNA [p = 0.15]; ruptured AAA [rAAA]: 38% NA vs. 28.6% NNA [p = 0.32]) or 30-day major adverse events (iAAA: 7% NA vs. 4.6% NNA [p = 0.22]; rAAA: 28% NA vs. 36.7% NNA [p = 0.35]) were observed.

CONCLUSIONS

Age was identified as an independent predictor of 30-day mortality after EVAR on multivariate analysis. However, no differences were found after PSM, suggesting that being ≥90 years of age but with similar comorbidities to younger patients is not associated with a higher short-term mortality after EVAR. Age ≥90 years alone should not exclude patients from EVAR, and tailored indications and carefully balanced risk assessment are advised.

Editor's Choice - Optimal Threshold for the Volume-Outcome Relationship After Open AAA Repair in the Endovascular Era: Analysis of the International Consortium of Vascular Registries

OBJECTIVE

As open abdominal aortic aneurysm (AAA) repair (OAR) rates decline in the endovascular era, the endorsement of minimum volume thresholds for OAR is increasingly controversial, as this may affect credentialing and training. The purpose of this analysis was to identify an optimal centre volume threshold that is associated with the most significant mortality reduction after OAR, and to determine how this reflects contemporary practice.

METHODS

This was an observational study of OARs performed in 11 countries (2010 - 2016) within the International Consortium of Vascular Registry database (n = 178 302). The primary endpoint was post-operative in hospital mortality. Two different methodologies (area under the receiving operating curve optimisation and Markov chain Monte Carlo procedure) were used to determine the optimal centre volume threshold associated with the most significant mortality improvement.

RESULTS

In total, 154 912 (86.9%) intact and 23 390 (13.1%) ruptured AAAs were analysed. The majority (63.1%; n = 112 557) underwent endovascular repair (EVAR) (OAR 36.9%; n = 65 745). A significant inverse relationship between increasing centre volume and lower peri-operative mortality after intact and ruptured OAR was evident (p < .001) but not with EVAR. An annual centre volume of between 13 and 16 procedures per year was associated with the most significant mortality reduction after intact OAR (adjusted predicted mortality < 13 procedures/year 4.6% [95% confidence interval 4.0% - 5.2%] vs. ≥ 13 procedures/year 3.1% [95% CI 2.8% - 3.5%]). With the increasing adoption of EVAR, the mean number of OARs per centre (intact + ruptured) decreased significantly (2010 - 2013 = 35.7; 2014 - 2016 = 29.8; p < .001). Only 23% of centres (n = 240/1 065) met the ≥ 13 procedures/year volume threshold, with significant variation between nations (Germany 11%; Denmark 100%).

CONCLUSION

An annual centre volume of 13 - 16 OARs per year is the optimal threshold associated with the greatest mortality risk reduction after treatment of intact AAA. However, in the current endovascular era, achieving this threshold requires significant re-organisation of OAR practice delivery in many countries, and would affect provision of non-elective aortic services. Low volume centres continuing to offer OAR should aim to achieve mortality results equivalent to the high volume institution benchmark, using validated data from quality registries to track outcomes.

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.

Nineteen-year outcomes with the Anaconda stent graft system from two tertiary centers

OBJECTIVE

The Anaconda stent graft device presents peculiar and unique features in its design and deployment sequence, available on the market for many years with minor modifications, among different generations. The aim of this study was to assess the long-term, real-life, outcomes obtained in two high-volume centers with this endograft for infrarenal aortic aneurysms treatment over a period of 19 years.

METHODS

All patients treated with the investigated device between 2000 and 2019, with at least 1 year of follow-up, were entered into a prospective database and data were reviewed retrospectively. The long-term results were assessed according to the Kaplan-Meier method. Primary outcomes were overall survival, freedom from AAA rupture, and freedom from AAA-related death. Secondary outcomes were freedom from late reintervention, freedom from late conversion to open repair, freedom from late limb occlusion, and freedom from late EVAR failure.

RESULTS

A total of 260 consecutive patients were treated during the study period. Technical success was achieved in 98.5% (256/260) of the cases. Two perioperative deaths (0.8%) and four major complications (1.5%) were recorded. At a mean follow-up of 54 ± 38 months (summary follow-up index = 0.86), the late survival estimate was 94.8% at 1 year, 75.2% at 5 years, 50.5% at 10 years, and 43.3% at 13 years, with no case of late AAA rupture or late AAA-related death. Late freedom from conversion was 99.2% at 1 year, 96.9% at 5 years, 94.0% at 10 years, and 94.0% at 13 years. Freedom from late limb thrombosis was 96.8% at 1 year and 91.0% at 5, 10, and 13 years. Estimates of freedom from late reintervention was 95.6% at 1 year, 87.0% at 5 years, 77.4% at 10 years, and 77.4% at 13 years. Estimates of limb thrombosis at 11 years were significantly different in patients receiving or not intraoperative iliac kissing balloon maneuver with noncompliant angioplasty catheters (98.0% vs 88.4%; P = .029).

CONCLUSIONS

The Anaconda stent graft demonstrated effective and durable outcomes for AAA treatment over a 19-year period, with no case of late AAA rupture or AAA related death in the studied population. Late limb occlusion was the leading cause of reintervention; however, a positive prevention strategy was found in intraoperative kissing balloon, which was associated with significant reduced rate of iliac thrombosis over time.

Female Sex and Outcomes after Endovascular Aneurysm Repair for Abdominal Aortic Aneurysm: A Propensity Score Matched Cohort Analysis

OBJECTIVE

Previous studies have showed a potential disadvantage of female patients who underwent abdominal aortic aneurysm (AAA) repair. The current study aims to determine sex-specific perioperative and long-term outcomes using propensity score matched unselected nationwide health insurance claims data.

METHODS

Insurance claims from a large German fund were used, covering around 8% of the insured German population. Patients who underwent endovascular aortic repair (EVAR) for intact AAA from 1 January 2011 to 30 April 2017 were included in the cohort. A 1:2 female to male propensity score matching was applied to adjust for confounding variables. Perioperative and long-term outcomes after 5 years were determined using matching and regression methods.

RESULTS

Among a total of 3736 patients (19.3% females, mean 75 years) undergoing EVAR for intact AAA, we identified 1863 matched patients. Before matching, females were more likely to be previously diagnosed with hypothyroidism, electrolyte disorders, rheumatoid disorders, and depression, while males were more often diabetics. In the matched sample, 23.4% of the females and 25.8% of the males died during a median follow-up of 776 and 792 days, respectively. Perioperatively, females were more likely to exhibit acute limb ischemia (5.3% vs. 3.2%, p = 0.031) and major bleeding (22.0% vs. 15.9%, p = 0.001) before they were discharged to rehabilitation (5.5% vs. 1.5%, p < 0.001) when compared to males. No statistically significant difference in perioperative (odds ratio 1.12, 95% CI 0.54-2.16) or long-term mortality (hazard ratio 0.91, 95% CI 0.76-1.08) was observed between sexes. This was also true regarding aortic reintervention rates after 1 year (2.0% vs. 2.9%) and 5 years (10.9% vs. 8.1%).

CONCLUSION

The current retrospective matched analysis of insurance claims revealed high early access-related morbidity in females when compared to their male counterparts. Short-term or long-term survival and reintervention outcomes were similar between sexes.

Editor's Choice - The GermanVasc Score: A Pragmatic Risk Score Predicts Five Year Amputation Free Survival in Patients with Peripheral Arterial Occlusive Disease

OBJECTIVE

Patients with peripheral arterial occlusive disease (PAOD) face an increased risk of both lower limb amputation and death. To date, it has been challenging to predict the long term outcomes for PAOD. The aim was to develop a risk score to predict worse five year amputation free survival (AFS).

METHODS

In this retrospective analysis of claims data, symptomatic PAOD patients were split into training and validation sets. Variables in the model were patient age and sex, Elixhauser comorbidities, and the 190 most common secondary diagnoses. Penalised Cox regression (least absolute shrinkage and selection operator [LASSO]) with tenfold cross validation for variable selection was performed and patients were categorised into five risk groups using the ten most important variables. All analyses were stratified by intermittent claudication (IC) and chronic limb threatening ischaemia (CLTI).

RESULTS

In total, 87 293 patients with PAOD (female 45.3%, mean age 71.4 ± 11.1 years) were included in the analysis. The most important variable predicting worse five year AFS was patient age >80 years. The GermanVasc score exhibited good predictive accuracy both for IC (c statistic = 0.70, 95% confidence interval [CI] 0.69-0.71) and CLTI (c statistic = 0.69, 95% CI 0.68-0.70) with adequate calibration due largely to alignment of observed and expected risk. Depending on the cumulative point score, the five year risk of amputation or death ranged from 9% (low risk) to 48% (high risk) for IC, and from 25% to 88% for CLTI.

CONCLUSION

The GermanVasc score predicts worse five year AFS stratified for inpatients suffering from IC and CLTI, with good predictive accuracy. By separating low from high risk patients, the GermanVasc score may support patient centred consent.

Occurrence and outcomes of type 3 endoleaks in endovascular aortic repair within the Vascular Quality Initiative database

Objectives

Type 3 endoleaks (T3ELs) represent a lack of aneurysm protection from systemic pressure. Previous studies have found a ~2% incidence of T3EL after standard infrarenal endovascular aneurysm repair (EVAR); however, no prior studies with new-generation devices have been able to determine an association between T3EL and clinical outcomes. Here we examine T3EL within the Society for Vascular Surgery Vascular Quality Initiative (VQI) to define rates of occurrence, rates and modes of reintervention, and clinical consequences of these endoleaks.

Design and setting

Participants receiving infrarenal EVAR in the VQI from January 2003 to September 2018 were analyzed in a retrospective cohort study.

Participants

Of 42 246 entries in the EVAR procedural registry, 41 604 had complete procedural information and were included in analysis. Of these, 36 082 had long-term follow-up, and 26 422 had follow-up (9-21 months per VQI reporting standards) with complete endoleak data recorded.

Interventions

All patients included in this study underwent an infrarenal EVAR.

Results

Within the VQI database, the rate of T3EL in infrarenal EVAR during index hospitalization was 0.37% (n=157/41 604), of which 85% were due to midgraft separation and 15% were due to fabric disruptions. Out of the 157 index hospitalization T3ELs, 4.5% (n=7) received procedural reintervention during that hospitalization, which accounted for 1% of all index hospitalization reinterventions. During the 21-month follow-up, the rate of incident T3EL was 0.7% (n=205/26 422), which accounted for 5% of all endoleaks seen during follow-up. Reinterventions for incident T3EL at follow-up were done in 30 patients (rate 0.1%), which accounted for 9% of endoleak reinterventions and 3.3% of all reinterventions. The presence of incident T3EL found during follow-up was associated with a significant decrease in 5-year survival (74% vs 80%, respectively; p=0.041) in Kaplan-Meier analysis.

Conclusion

T3ELs rates at placement and follow-up remain low; however, the majority reported in long-term follow-up are incident and these incident endoleaks are associated with decreased survival in EVAR.

An experimental evaluation of a concept to improve conventional aortic prostheses

Conventionally used textile prosthesis for traditional open surgical repair (OSR) of aortic aneurysms have a lower compliance than the native aortic tissue. Graft placements lead to an acute drop in compliance which effects cardiovascular risk and the development of graft related complications. A custom-made spring casing was applied to a Dacron graft segment under physiological pressure conditions within a five-element biventricular mock circulation loop, to investigate experimentally a concept to improve the compliance of a conventional aortic prosthesis by changing the transverse graft cross-section. Two different prosthesis locations, proximal and distal of compliant silicone tubing were used to study uniaxial graft compression with an elastic device. To characterise the devices' performance by means of pulse pressure (PP), diastolic pressure (P_dia) and pulse wave velocity(PWV), fluid pressures and flow were recorded. In a proximal graft setting (ascending aorta repair) elastic uniaxial compression with a custom-made spring casing (2 cm width) could significantly reduce PP by 10-14% (p < .001) and slowed PWV from 6.7 to 5.2 m/s (22%, p = .002). Applied to a graft in a distal position, the spring casing demonstrated less impact on PP (2-10%), but significantly reduced PWV in this mock aorta segment from 13.7 to 5.5 m/s (60%, p = .004). In conclusion, a newly conceptualised spring casing applied to the external wall of synthetic aortic grafts can reduce PP and slow PWV. By restoring elastic aortic recoil in stiff textile aortic prostheses, the presented concept is a potential solution to improve long-term aortic prosthesis related complications.

Vogl T, T. Grundmann R. Endovascular and Open Repair of Abdominal Aortic Aneurysm

BACKGROUND

This review presents the surgical indications, surgical procedures, and results in the treatment of asymptomatic and ruptured abdominal aortic aneurysms (AAA).

METHODS

An updated search of the literature on screening, diagnosis, treatment, and follow-up of AAA, based on the German clinical practice guideline published in 2018.

RESULTS

Surgery is indicated in men with an asymptomatic AAA ≥ 5.5 cm and in women, ≥ 5.0 cm. The indication in men is based on four randomized trials, while in women the data are not conclusive. The majority of patients with AAA (around 80%) meanwhile receive endovascular treatment (endovascular aortic repair, EVAR). Open surgery (open aneurysm repair, OAR) is reserved for patients with longer life expectancy and lower morbidity. The pooled 30-day mortality is 1.16% (95% confidence interval [0.92; 1.39]) following EVAR, 3.27% [2.7; 3.83] after OAR. Women have higher operative/interventional mortality than men (odds ratio 1.67%). The mortality for ruptured AAA is extremely high: around 80% of women and 70% of men die after AAA rupture. Ruptured AAA should, if possible, be treated via the endovascular approach, ideally with the patient under local anesthesia. Treatment at specialized centers guarantees the required expertise and infrastructure. Long-term periodic monitoring by mean of imaging (duplex sonography, plus computed tomography if needed) is essential, particularly following EVAR, to detect and (if appropriate) treat endoleaks, to document stable diameter of the eliminated aneurysmal sac, and to determine whether reintervention is necessary (long-term reintervention rate circa 18%).

CONCLUSION

Vascular surgery now offers a high degree of safety in the treatment of patients with asymptomatic AAA. Endovascular intervention is preferred.

Integrated Plasma and Tissue Proteomics Reveals Attractin Release by Intraluminal Thrombus of Abdominal Aortic Aneurysms and Improves Aneurysm Growth Prediction in Humans

OBJECTIVE

Discovery of novel biomarkers for abdominal aortic aneurysm growth (AAA) prediction.

BACKGROUND

Novel biomarker of AAA growth is a recognised priority in research. Our prior work implicated intraluminal thrombus (ILT) in AAAs to be a potential source of systemic mediators during AAA progression. Here we applied a mass spectrometry proteomics pipeline to discover novel biomarkers for AAA growth prediction.

METHODS

Patients were prospectively recruited. Plasma samples were collected at baseline (n = 62). AAA growth was recorded at 12 months. In Experiment 1, plasma samples from the fastest and slowest growth patients (n = 10 each) were compared. In Experiment 2, plasma samples were collected before and at 10-12 weeks after surgery (n = 29). In Experiment 3, paired ILT and omental biopsies were collected intra-operatively during open surgical repair (n = 3). In Experiment 4, tissue secretome was obtained from ex-vivo culture of these paired tissue samples. Samples were subjected to a liquid chromatography tandem mass spectrometry (LC-MS/MS) workflow to discover novel biomarkers.

RESULTS

We discovered 3 proteins that are: (i) present in ILT; (ii) released by ILT; (iii) reduced in circulation after AAA surgery; (iv) differs between fast and slow growth AAAs. One of these is Attractin. Plasma Attractin correlates significantly with future AAA growth (Spearman r = 0.35, P < 0.005). Using Attractin and AAA diameter as input variables, the AUROC for predicting no growth and fast growth of AAA at 12 months is 85% and 76%, respectively.

CONCLUSION

We show that ILT of AAAs releases mediators during the natural history of AAA growth. These are novel biomarkers for AAA growth prediction in humans.

Editor's Choice - International Variations and Sex Disparities in the Treatment of Peripheral Arterial Occlusive Disease: A Report from VASCUNET and the International Consortium of Vascular Registries

OBJECTIVE

The aim of this study was to determine sex specific differences in the invasive treatment of symptomatic peripheral arterial occlusive disease (PAOD) between member states participating in the VASCUNET and International Consortium of Vascular Registries.

METHODS

Data on open surgical revascularisation and peripheral vascular intervention (PVI) of symptomatic PAOD from 2010 to 2017 were collected from population based administrative and registry data from 11 countries. Differences in age, sex, indication, and invasive treatment modality were analysed.

RESULTS

Data from 11 countries covering 671 million inhabitants and 1 164 497 hospitalisations (40% women, mean age 72 years, 49% with intermittent claudication, 54% treated with PVI) in Europe (including Russia), North America, Australia, and New Zealand were included. Patient selection and treatment modality varied widely for the proportion of female patients (23% in Portugal and 46% in Sweden), the proportion of patients with claudication (6% in Italy and 69% in Russia), patients' mean age (70 years in the USA and 76 years in Italy), the proportion of octogenarians (8% in Russia and 33% in Sweden), and the proportion of PVI (24% in Russia and 88% in Italy). Numerous differences between females and males were observed in regard to patient age (72 vs. 70 years), the proportion of octogenarians (28% vs. 15%), proportion of patients with claudication (45% vs. 51%), proportion of PVI (57% vs. 51%), and length of hospital stay (7 days vs. 6 days).

CONCLUSION

Remarkable differences regarding the proportion of peripheral vascular interventions, patients with claudication, and octogenarians were seen across countries and sexes. Future studies should address the underlying reasons for this, including the impact of national societal guidelines, reimbursement, and differences in health maintenance.

Evolving Utility of Endovascular Treatment of Juxtarenal, Pararenal, and Suprarenal Abdominal Aortic Aneurysms Associated With Increased Risk of Mortality Over Time

BACKGROUND

Continued advances in endovascular technologies are resulting in fewer open abdominal aortic aneurysm (AAA) repairs. In addition, more complex juxtarenal, pararenal, and suprarenal (JPS) AAAs are being managed with various endovascular techniques. This study sought to evaluate the evolving trends in endovascular aneurysm repair (EVAR) of AAAs, hypothesizing increased rate of JPS AAA repair by EVAR. We also sought to evaluate the risk for morbidity and mortality for EVAR and open aneurysm repair (OAR) of JPS AAAs over time.

METHODS

The 2011-2017 American College of Surgeons National Surgical Quality Improvement Program Procedure-Targeted Vascular database was queried for patients undergoing OAR or EVAR for AAAs. A multivariable logistic regression analysis was performed for both infrarenal and JPS AAA repairs.

RESULTS

Of 18,661 patients who underwent AAA repair, 3,941 (21.1%) were OAR and 14,720 (78.9%) were EVAR. The rate of OAR decreased from 29.5% in 2011 to 21.3% in 2017 (P < 0.001) with a geometric-mean-annual decrease of 27.8%. The rate of EVAR increased from 70.5% to 78.7% during the same time period (P < 0.001) with a geometric-mean-annual increase of 11.6%. These trends remained true for both infrarenal and JPS AAAs. After adjusting for covariates, there was no difference in associated risk of 30-day mortality, renal complications, or ischemic colitis for either OAR or EVAR over each incremental year for infrarenal AAAs (P > 0.05). However, in patients undergoing EVAR for JPS AAAs, the associated risk of mortality increased with each incremental year (odds ratio [OR]: 1.30, confidence interval [CI]: 1.01-1.69, P = 0.039), whereas there was no difference in the risk of mortality for OAR of JPS AAAs with each incremental year (OR: 1.11, CI: 0.99-1.23, P = 0.067).

CONCLUSIONS

The rate of OAR for AAA has decreased over the past seven years with an increase in EVAR, particularly for more complex JPS AAAs. The associated risk for morbidity and mortality for treatment of infrarenal AAAs was not significantly affected by this increased utility of EVAR. The associated risk of mortality for JPS AAAs treated by EVAR increased over time, whereas this trend for associated risk of mortality was not seen for OAR of JPS AAAs. These findings, especially the increased associated risk of mortality over time with EVAR for JPS AAAs, warrant careful prospective analysis.

Management of Abdominal Aortic Aneurysm Disease: Similarities and Differences Among Cardiovascular Guidelines and NICE Guidance

The development of endovascular techniques has improved abdominal aortic aneurysm (AAA) management over the past 2 decades. Different cardiovascular societies worldwide have recommended the endovascular approach as the standard of care in their currently available guidelines. While endovascular treatment has established its role in daily clinical practice, a new debate has arisen regarding the indications, appropriateness, limitations, and role of open surgery. To inform this debate, the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases were searched from 2010 to May 2020; the systematic search identified 5 articles published between 2011 and 2020 by 4 cardiovascular societies and the National Institute of Health and Care Excellence (NICE). Four debatable domains were assessed and analyzed: diagnostic methods and screening, preoperative management, indications and treatment modalities, and postoperative follow-up and endoleak management. The review addresses controversial proposals as well as widely accepted recommendations and "gray zone" issues that need to be further investigated and analyzed, such as screening in women, medical management, and follow-up imaging. While the recommendations for AAA management have significant overlap and agreement among international cardiovascular societies, the NICE guidelines diverge regarding the role of open repair in aortic disease, recommending conventional surgery in most elective cases.

Editor's Choice - Volume-Outcome Relationships in Elective Abdominal Aortic Aneurysm Surgery: Analysis of the UK Hospital Episodes Statistics Database for the Getting It Right First Time (GIRFT) Programme

OBJECTIVE

To investigate whether a volume-outcome relationship exists for elective abdominal aortic aneurysm (AAA) surgery conducted within the National Health Service (NHS) in England.

METHODS

This was an analysis of administrative data. Data were extracted from the Hospital Episodes Statistics database for England from April 2011 to March 2019 for all adult admissions for elective infrarenal AAA surgery. Data were extracted for the NHS trust and surgeon undertaking the procedure, the surgical technique used (open or endovascular), the financial year of admission, length of hospital and critical care stay during the procedure and subsequent emergency re-admissions (primary outcome) and deaths within 30 days. Multilevel modelling was used to adjust for hierarchy and confounding.

RESULTS

A dataset of 31 829 procedures (8867 open, 22 962 endovascular) was extracted. For open surgery, lower trust annual volume was associated with higher 30 day emergency re-admission rates and higher 30 day mortality. For open surgery, lower surgeon annual volume was associated with higher 30 day mortality and length of hospital stay greater than the median. For endovascular surgery, lower surgeon annual volume was associated with not having an overnight stay in critical care. None of the other volume-outcome relationships investigated was significant.

CONCLUSION

For elective infrarenal AAA surgery in the UK NHS, there was strong evidence of a volume-outcome relationship for open surgery. However, evidence for a volume-outcome relationship is dependent on the specific procedure undertaken and the outcome of interest.

Quality of care in surgical/interventional vascular medicine: what can routinely collected data from the insurance companies achieve?

The complexity and diversity of surgical/interventional vascular medicine necessitate innovative and pragmatic solutions for the valid measurement of the quality of care in the long term. The secondary utilization of routinely collected data from social insurance institutions has increasingly become the focus of interdisciplinary medicine over the years. Owing to their longitudinal linkage and pan-sector generation, routinely collected data make it possible to answer important questions and can complement quality development projects with primary registry data. Various guidelines exist for their usage, linkage, and reporting. Studies have shown good validity, especially for endpoints with major clinical relevance. The numerous advantages of routinely collected data face several challenges that require thorough plausibility and validity procedures and distinctive methodological expertise. This review presents a discussion of these advantages and challenges and provides recommendations for starting to use this increasingly important source of data.

Medicare costs for endovascular abdominal aortic aneurysm treatment in the Vascular Quality Initiative

BACKGROUND

Reintervention after endovascular repair (EVR) of abdominal aortic aneurysms is common. However, the cumulative financial impact of reintervention after EVR on a national scale is poorly defined. Our objective was to describe the cost to Medicare for aneurysm treatment (EVR plus reinterventions) among a cohort of patients with known follow-up for 5 years after repair.

METHODS

We identified patients who underwent EVR within the Vascular Quality Initiative who were linked to their respective Medicare claims file (n = 13,995). We excluded patients who underwent EVR after September 30, 2010, and those who had incomplete Medicare coverage (n = 12,788). The remaining cohort (n = 1207) had complete follow-up until death or 5 years (Medicare data available through September 30, 2015). We then obtained and compiled the corresponding Medicare reimbursement data for the index EVR hospitalization and all subsequent reinterventions.

RESULTS

We studied 1207 Medicare patients who underwent EVR and had known follow-up for reinterventions for 5 years. The mean age was 76.2 years (±7.1 years), 21.6% of patients were female, and 91.1% of procedures were elective. The Kaplan-Meier reintervention rate at 5 years was 18%. Among patients who underwent reintervention, 154 (73.7%) had a single reintervention, 40 (19.1%) had two reinterventions, and 15 (7.2%) had three or more reinterventions. The median cost to Medicare for the index EVR hospitalization was $25,745 (interquartile range, $21,131-$28,774). The median cost for subsequent reinterventions was $22,165 (interquartile range, $17,152-$29,605). The cumulative cost to Medicare of aneurysm treatment (EVR plus reinterventions) increased in a stepwise fashion among patients who underwent multiple reinterventions, with each reintervention being similar in cost to the index EVR.

CONCLUSIONS

The overall cost incurred by Medicare to reimburse for each reintervention after EVR is roughly the same as for the initial procedure itself, meaning that Medicare cost projections would be greater than $100,000 for any individual who undergoes an EVR with three reinterventions. The long-term financial impact of EVR must be considered by surgeons, patients, and healthcare systems alike as these cumulative costs may hinder the fiscal viability of an EVR-first therapeutic approach and highlight the need for judicious patient selection paradigms.

Paradigm shifts in abdominal aortic aneurysm management based on vascular registries

Abdominal aortic aneurysm (AAA) is a relatively common and potentially fatal disease. The management of AAA has undergone extensive changes in the last two decades. High quality vascular surgical registries were established early and have been found to be instrumental in the evaluation and monitoring of these changes, most notably the wide implementation of minimally invasive endovascular surgical technology. Trends over the years showed the increased use of endovascular aneurysm repair (EVAR) over open repair, the decreasing perioperative adverse outcomes and the early survival advantage of EVAR. Also, data from the early EVAR years changed the views on endoleak management and showed the importance of tracking the implementation of new techniques. Registry data complemented the randomized trials performed in aortic surgery by showing the high rate of laparotomy-related reinterventions after open repair. Also, they are an essential tool for the understanding of outcomes in a broad patient population, evaluating the generalizability of findings from randomized trials and analysing changes over time. By using large-scale data over longer periods of time, the importance of centralization of care to high-volume centres was shown, particularly for open repair. Additionally, large-scale databases can offer an opportunity to assess practice and outcomes in patient subgroups (e.g. treatment of AAA in women and the elderly) as well as in rare aortic pathologies. In this review article, we point out the most important paradigm shifts in AAA management based on vascular registry data.

Big data in vascular surgery: registries, international collaboration and future directions

Given the increasing availability of large data set, small single-institutional series raise decreasing attention. Rapid expansion of technology from electronic medical records to easily accessible internet access, and widespread use and acceptance of registries in the medical world has allowed for research and quality improvement efforts using 'big data'. Big data, although technically not defined, typically refers to large databases that can be used to investigate common or rare disease processes or outcomes, describe variation in clinical practices across and between different specialties at various practice location, whilst allowing important information about trends over time. Big data have allowed investigators to quickly assimilate cohorts of patients and/or procedures to answer current questions, with more complete population representation and improved generalizability whilst decreasing the likelihood of power problems and type II errors. On the other hand, pitfalls still exist with the growing problem of hypothesis fishing, lack of granularity and the fear by many clinicians that registry transparency may have already gone too far, where surgery groups or individual surgeon outcomes are readily available to patients and referring providers. Within vascular surgery specifically, big data have expanded over the last decade and now includes regional, national and global registries that have major benefits of gathering specific clinical and procedural information within vascular surgery. In this review, we highlight the main vascular surgery registries and recap a few success stories of how the registries have been leveraged to benefit discovery, quality improvement and ultimately patient care. Additionally, we outline future directions that will be imperative for continued expansion, acceptance and adoption of 'big data' utilization inpatients with vascular disease.

Variation in Surgical Treatment of Abdominal Aortic Aneurysms With Small Aortic Diameters in the Netherlands

OBJECTIVE

To evaluate reasons to deviate from aneurysm diameter thresholds, and focus on the difference in how Dutch vascular surgical units (VSUs) perceive their deviation and their actual deviation.

BACKGROUND

Guidelines recommend surgical treatment for asymptomatic abdominal aortic aneurysms (AAAs) with a diameter of at least 55 mm for men and 50 mm for women. We evaluate reasons to deviate from these guidelines, and focus on the difference in how Dutch vascular surgical units (VSUs) perceive their deviation and their actual deviation.

METHODS

All patients undergoing elective AAA repair between 2013 and 2016 registered in the Dutch Surgical Aneurysm Audit (DSAA) were included. Surgery at diameters of <55 mm for men and <50 mm for women were considered guideline deviations. National deviation and hospital variation in deviation were evaluated over time. Questionnaires were distributed among all Dutch VSUs, inquiring for acceptable reasons for guideline deviation. VSUs were asked to estimate the guideline deviation percentage in their hospital which was then compared with their DSAA percentage.

RESULTS

In all, 9039 patients were included. In 15%, we found guideline deviation, varying from 2% to 40% between VSUs. Over time, 21 VSUs were identified with a lower percentage of deviation than the national mean each year and 8 VSUs with a higher percentage. 44/60 VSUs completed the questionnaire. Most commonly reported reasons to deviate were concomitant large iliac diameter (91%) and saccular aneurysm (82%). The majority of the VSUs (77%) estimated their guideline deviation to be <5%. Eleven VSUs (25%) estimated their deviation concordant with their DSAA percentage, but 75% of VSUs underestimated their deviation.

CONCLUSIONS

Dutch VSUs regularly deviate from the guidelines regarding aneurysm diameter, with variation between VSUs. Consensus exists amongst VSUs on acceptable reasons for guideline deviations; however, the majority underestimates their actual deviation percentage.

Operators believe patient-specific rehearsal improve individual and team performance

INTRODUCTION

Rehearsing endovascular aortic aneurysm repair on patient-specific data is recent within virtual reality simulation and opens up new possibilities for operators to prepare for complex procedures. This study evaluated the feasibility of patient-specific rehearsal (PsR) and assessed operators' appraisal of the VIST-LAB simulator from Mentice.

MATERIAL AND METHODS

CT-data was segmented and uploaded to the simulator, and simulated for 30 elective EVAR patients. Operators were asked how they perceived the PsR on a Likert scale after the PsR (once) and after the following procedure (each time).

RESULTS

Patients were simulated and operated by 14 operators, always in pairs of one vascular surgeon and one interventional radiologist. The operators estimated that PsR improved individual and team performance (median 4), and recommended the use of PsR in general (median 4) and for difficult cases (median 5). The simulator realism got moderate scores (median 2-3). Inexperienced operators seemed to appreciate the PsR the most.

CONCLUSIONS

PsR was feasible and was evaluated by operators to improve individual and team performance. Inexperienced users were more positive towards PsR than experienced users. PsR realism and the ease of importing patient-specific data can still be improved, and further studies to quantify and precisely identify benefits are needed.

Altered IL-32 Signaling in Abdominal Aortic Aneurysm

INTRODUCTION AND OBJECTIVE

Interleukin (IL)-32 is a pro-inflammatory cytokine not previously studied in relation to abdominal aortic aneurysm (AAA). The aim of this study was to elucidate the expression and localization of IL-32 in AAA.

METHODS

Expression and localization of IL-32 in human aortic tissue was studied with immunohistochemical analysis and Western blot (AAA: n = 5; controls: n = 4). ELISA was used to measure IL-32 in human plasma samples (AAA: n = 140; controls: n = 37) and in media from cultured peripheral blood mononuclear cells (PBMCs) from 3 healthy donors. IL-32 mRNA in PBMCs, endothelial cells, aortic smooth muscle cells (SMCs), and aortic tissue samples of AAA (n = 16) and control aortas (n = 9) was measured with qPCR.

RESULTS

IL-32 was predominantly expressed in SMCs and T-cell-rich areas. Highest mRNA expression was observed in the intima/media layer of the AAA. A weaker protein expression was detected in non-aneurysmal aortas. Expression of IL-32 was confirmed in isolated T cells, macrophages, endothelial cells, and SMCs, where expression was also inducible by cytokines such as interferon-γ. There was no difference in IL-32 expression in plasma between patients and controls.

CONCLUSION

IL-32 signaling is altered locally in AAA and could potentially play an important role in aneurysm development. Further studies using animal models would be helpful to study its potential role in AAA disease.

Mortality from abdominal aortic aneurysm: trends in European Union 15+ countries from 1990 to 2017

BACKGROUND

This observational study assessed trends in abdominal aortic aneurysm (AAA) death rates in European Union (EU) 15+ countries for the years 1990 to 2017.

METHODS

Age-standardized death rates (ASDRs) were extracted from the Global Burden of Disease Study Global Health Data Exchange. Trends were analysed using joinpoint regression analysis.

RESULTS

Between 1990 and 2017, ASDRs from AAA decreased in all 19 EU15+ countries for women, and in 18 of 19 countries for men. Increasing AAA mortality was observed only for men in Greece (+5·3 per cent). The largest relative decreases in ASDR between 1990 and 2017 were observed in Australia (men -65·6 per cent, women -50·4 per cent) and Canada (men -60·8 per cent, women -48·6 per cent). Over the 28-year interval, the smallest decreases in ASDR for women were noted in Greece (-2·3 per cent) and in Italy (-2·5 per cent). In 2017, the highest mortality rates were observed in the UK for both men and women (7·5 per 100 000 and 3·7 per 100 000 respectively). The lowest ASDR was observed in Portugal for men (2·8 per 100 000) and in Spain for women (1·0 per 100 000). ASDRs for AAA in 2017 were higher for men than women in all 19 EU15+ countries. The most recent trends demonstrated increasing AAA ASDRs in 14 of 19 countries for both sexes; the increases were relatively small compared with the improvements in the preceding years.

CONCLUSION

This observational study identified decreasing mortality from AAA across EU15+ countries since 1990. The most recent trends demonstrated relatively small increases in AAA mortality across the majority of EU15+ countries since 2012.

Hospital Volume Matters: The Volume-Outcome Relationship in Open Juxtarenal AAA Repair

OBJECTIVE

We studied whether the volume-outcome relationship would persist in more complex aortic operations.

BACKGROUND

Despite the added complexity of the involvement of the renal arteries in open juxtarenal abdominal aortic aneurysm (AAA) repair, the volume effect in these difficult operations has yet to be defined.

METHODS

We identified all patients in the Vascular Quality Initiative (VQI) who underwent open AAA repair from 2003 to 2016. We calculated each hospital's average annual volume for total open AAA repairs, and total open juxtarenal AAA repairs. We compared adjusted perioperative and long-term survival across quintiles of hospital volume, and constructed models including both volume metrics to evaluate the cross-volume effects.

RESULTS

Of 8880 total open AAA repairs, there were 3470 open juxtarenal cases. Centers with low (<4), medium (4-14), and high (>14) volumes of open juxtarenal repair demonstrated adjusted perioperative mortality of 9.0%, 4.9%, and 3.9%, respectively (P < 0.01). When both volume metrics were considered, open juxtarenal volume, but not total open AAA volume was associated with perioperative mortality (lowest quintile of juxtarenal volume: OR 2.36 [1.29-4.30], P < 0.01). Hospital volume was not associated with adjusted long-term mortality. High volume centers were more likely to use renal protective strategies such as mannitol and cold renal perfusion (both P < 0.01). Low volume centers performed a similar proportion of cases each year, but 22 centers (13%) did stop performing repairs during the study period.

CONCLUSION

Hospitals with low annualized volumes of open juxtarenal repair have higher perioperative mortality, irrespective of their total open aortic volume. Complex open AAA repairs should be performed at experienced centers, and future efforts should focus on centralization of complex aortic care.

Impact of Centralisation on Abdominal Aortic Aneurysm Repair Outcomes: Early Experience in Catalonia

OBJECTIVE

Several studies have revealed high volume centres have better outcomes in the treatment of abdominal aortic aneurysms (AAAs), thus supporting centralisation of this procedure into selected centres based on volume. To date however, the real benefit of centralisation of this pathology has not been well demonstrated. The aim of this study was to analyse the impact of centralisation in to high volume centres (defined as those performing more than 30 cases per year) on AAA treatment outcomes carried out in Catalonia (Spain).

METHODS

Data were collected from official national registries (HDMBD) for AAA treated by endovascular aneurysm repair (EVAR) or open repair (OR) over a nine year period. Two time periods were selected for comparison: before centralisation (2009-2014) and after complete centralisation (2015-2017). The primary objective was to determine short term mortality (in hospital and 30 day mortality) and length of stay (LOS) after intact AAA (iAAA) and ruptured AAA (rAAA) repair, before and after centralisation. Uni- and multivariable analyses were performed in order to identify independent outcomes predictors.

RESULTS

A total of 3 501 iAAAs, including 1 124 (32.1%) OR and 2377 (67.9%) EVAR, and 409 rAAAs, including 218 (53.3%) OR and 191 (46.7%) EVAR, were identified. After centralisation, there was a significant decrease in overall mortality in iAAA repair (4.7% vs. 2.0%, p < .001) and rAAA repair (53.1% vs. 41.9%, p = .028). Mortality reduction in iAAAs was significant for OR (8.7% vs. 3.6%, p = .005), but not for EVAR (2.2% vs. 1.5%, p = .25). Overall LOS decreased as well, mainly in iAAAs (9.49 ± 10.84 vs. 7.44 ± 12.23 days, p < .001), and in particular in elective EVAR (7.32 ± 7.73 vs. 6.00 ± 8.97 days, p < .001). Multivariable analysis was identified before the centralisation period as an independent predictor for both mortality (odds ratio 1.484, 95% CI 1.098-2.005, p = .010) and LOS (B coefficient 1.146, 95% CI 0.218-2.073, p = .016).

CONCLUSION

The implementation of a country based centralisation programme for AAA treatment led to a significant reduction in short term mortality, for both iAAA and rAAA, and mainly for elective OR. LOS also significantly decreased, mainly for elective EVAR. These results support the benefit of centralisation of AAA repair procedures.

Female sex is associated with comparable 5-year outcomes after contemporary endovascular aneurysm repair despite more challenging anatomy

BACKGROUND

Women with abdominal aortic aneurysms less often meet anatomic criteria for endovascular repair and experience worse perioperative and long-term survival.

METHODS

We compared long-term survival, aneurysm-related mortality, and rates of endoleaks and reinterventions between male and female patients in the Endurant Stent Graft Natural Selection Global Postmarket Registry (ENGAGE) using 2:1 propensity score matching.

RESULTS

There were 1130 male patients and 133 female patients, yielding 399 patients after matching (266 male patients, 133 female patients). Female patients were older, with smaller aneurysms, smaller iliac arteries, and shorter, more angulated necks, and they were more often treated outside the device instructions for use (all P < .001). Through 5 years, female patients experienced overall mortality comparable to that of well-matched male patients (34% vs 38%, respectively; hazard ratio, 0.89 [0.61-1.29]; P = .54) and lower aneurysm-related mortality (0% vs 3%; P = .047). Female patients experienced higher rates of any postoperative type IA endoleak through 5 years (10% vs 1%; P < .001) but comparable rates of secondary endovascular procedures (14% vs 16%; P = .40). Female sex was independently associated with significantly higher risk of long-term type IA endoleaks (hazard ratio, 4.8 [1.2-20.8]; P = .04), even after accounting for anatomic factors. No female patient experienced aneurysm rupture during follow-up, and only one female patient underwent conversion to open repair.

CONCLUSIONS

Despite more challenging anatomy, female patients in the ENGAGE registry had long-term outcomes comparable to those of male patients. However, female patients experienced higher rates of type IA endoleaks. Although standard endovascular aneurysm repair remains a viable solution for most women, whether high-risk patients may be better served with open surgery, custom-made devices, EndoAnchors (Aptus Endosystems, Sunnyvale, Calif), or chimneys is worthy of further study.

Editor's Choice - Assessment of Correlation Between Mean Size of Infrarenal Abdominal Aortic Aneurysm at Time of Intact Repair Against Repair and Rupture Rate in Nine Countries

OBJECTIVE

This study aimed to analyse the mean abdominal aortic aneurysm (AAA) diameter for repair in nine countries, and to determine variation in mean AAA diameter for elective AAA repair and its relationship to rupture AAA repair rates and aneurysm related mortality in corresponding populations.

METHODS

Data on intact (iAAA) and ruptured infrarenal AAA (rAAA) repair for the years 2010-2012 were collected from Denmark, England, Finland, Germany, Hungary, New Zealand, Norway, Sweden, and the USA. The rate of iAAA repair and rAAA per 100 000 inhabitants above 59 years old, mean AAA diameter for iAAA repair and rAAA repair, and the national rates of rAAA were assessed. National cause of death statistics were used to estimate aneurysm related mortality. Direct standardisation methods were applied to the national mortality data. Logistic regression and analysis of variance model adjustments were made for age groups, sex, and year.

RESULTS

There was a variation in the mean diameter of iAAA repair (n = 34 566; range Germany = 57 mm, Denmark = 68 mm). The standardised iAAA repair rate per 100000 inhabitants varied from 10.4 (Hungary) to 66.5 (Norway), p<.01, and the standardised rAAA repair rate per 100 000 from 5.8 (USA) to 16.9 (England), p<.01. Overall, there was no significant correlation between mean diameter of iAAA repair and standardised iAAA rate (r² = 0.04, p = .3). There was no significant correlation between rAAA repair rate (n = 12 628) with mean diameter of iAAA repair (r² = 0.2, p = .1).

CONCLUSION

Despite recommendations from learned society guidelines, data indicate variations in mean diameter for AAA repair. There was no significant correlation between mean diameter of AAA repair and rates of iAAA repair and rAAA repair. These analyses are subject to differences in disease prevalence, uncertainties in rupture rates, validations of vascular registries, causes of death and registrations.

Editor's Choice - Detection of Late Complications After Endovascular Abdominal Aortic Aneurysm Repair and Implications for Follow up Based on Retrospective Assessment of a Two Centre Cohort

OBJECTIVE

Endovascular aortic aneurysm repair (EVAR) is associated with the risk of late complications and mandates follow up. This retrospective study assessed post-EVAR complications in a two centre cohort. The study evaluated the rate of complications presenting with symptoms vs. those detected by imaging follow up. Additionally, the agreement between DUS and CTA in detecting complications was assessed in patients with both.

METHODS

All EVAR patients from 1998 to 2012 in two centres were included. Complications were classified based on whether they were symptomatic or detected by imaging, as well as based on imaging detection modality (DUS or CTA). For patients who had undergone DUS and CTA within three months of each other, the kappa coefficient of agreement was assessed.

RESULTS

Four hundred and fifty-four patients treated by EVAR were identified. The median follow up time was 5.2 (IQR 2.8-7.6) years. One hundred and eighteen patients (26%) developed 176 complications. One hundred and six (60.2%) of the complications were asymptomatic, and 70 (39.8%) were symptomatic. Two hundred and fifty-three patients had imaging with both modalities within three months of each other; the kappa coefficient for agreement between CTA and DUS for detecting clinically significant complications was 0.91. Regarding CTA as the standard modality, DUS had a sensitivity of 88.8% (95% CI 77.3-95.8%) and a specificity of 99.4% (95% CI 97.1-99.9%). Three of the complications missed by DUS were related to loss of proximal and distal seal, all occurring in patients with short sealing length on first post-operative CT scan.

CONCLUSION

Approximately a quarter of the patients developed complications, the majority of which were asymptomatic, underlining the importance of adequate surveillance. There was good agreement between CTA and DUS in detecting complications. Clinically significant complications related to inadequate seal were missed by DUS, suggesting that CTA still plays an important role in EVAR surveillance.

Perioperative Outcomes for Abdominal Aortic Aneurysm Repair Based on Aneurysm Diameter

BACKGROUND

Guidelines from the Society for Vascular Surgery recommend elective repair in asymptomatic patients with an abdominal aortic aneurysm (AAA) only if their diameter is greater than or equal to 5.5 cm, yet smaller ones are routinely repaired. This study aims to evaluate perioperative outcomes based on aneurysm size at the time of repair.

METHODS

Male patients who underwent elective endovascular aneurysm repair (EVAR) or open abdominal aneurysm repair (OAAR) repair of an infrarenal AAA were abstracted from 2011 to 2015 Targeted National Surgical Quality Improvement Program (NSQIP) database. Patients with symptoms or with aneurysmal extension into the visceral or iliac vessels were excluded. Outcomes of open versus endovascular repair were reported, with multivariate analyses to identify factors associated with the decision to repair AAA ≤5.4 cm.

RESULTS

A total of 2115 (90.9%) patients underwent EVAR, while 213 (9.1%) underwent OAAR. The mean diameter in patients who underwent OAAR was 6.1 cm (interquartile range [IQR]: 5.2-6.1 cm) versus 5.7 cm (IQR: 5.2-6.0 cm) for EVAR. However, in 42.5% of EVAR and 32.8% of OAAR patients, the diameter of the AAA was 5.4 cm or less. The group undergoing repair of AAA ≤5.4 cm was younger compared to the larger AAA group (71.9 vs 73.9 years; P < .0001). Patients older than 80 years were less likely to have a repair of AAA measuring ≤5.4 cm (odds ratio [OR] = 0.45, 95% confidence interval [CI] = 0.30-0.65). Additionally, patients who underwent EVAR were more likely to have AAA measuring ≤5.4 cm repaired compared to those who underwent OAAR (OR = 1.62, 95% CI = 1.19-2.21). There were no differences in perioperative morbidity or mortality between the groups.

CONCLUSION

There were no differences in perioperative outcomes after AAA repair, independent of aneurysm diameter. We found a higher likelihood of repairing AAA ≤5.4 cm in younger patients who were more likely to have been repaired with EVAR. Patients older than 80 years were less likely to undergo small AAA repair.