Center Volume is Associated with Diminished Failure to Rescue and Improved Outcomes Following Elective Open AAA Repair

Temporal Trends and Outcomes of Abdominal Aortic Aneurysm Care in the United States

BACKGROUND

Endovascular aortic aneurysm repair (EVAR) has had a dynamic impact on abdominal aortic aneurysm (AAA) care, often supplanting open AAA repair (OAR). Accordingly, US AAA management is often highlighted by disparities in patient selection and guideline compliance. The purpose of this analysis was to define secular trends in AAA care.

METHODS

The Society for Vascular Surgery Vascular Quality Initiative was queried for all EVARs and OARs (2011-2021). End points included procedure utilization, change in mortality, patient risk profile, Society for Vascular Surgery-endorsed diameter compliance, off-label EVAR use, cross-clamp location, blood loss, in-hospital complications, and post-EVAR surveillance missingness. Linear regression was used without risk adjustment for all end points except for mortality and complications, for which logistic regression with risk adjustment was used.

RESULTS

In all, 66 609 EVARs (elective, 85% [n=55 805] and nonelective, 15% [n=9976]) and 13 818 OARs (elective, 70% [n=9706] and nonelective, 30% [n=4081]) were analyzed. Elective EVAR:OAR ratios were increased (0.2 per year [95% CI, 0.01-0.32]), while nonelective ratios were unchanged. Elective diameter threshold noncompliance decreased for OAR (24%→17%; P=0.01) but not EVAR (mean, 37%). Low-risk patients increasingly underwent elective repairs (EVAR, +0.4%per year [95% CI, 0.2-0.6]; OAR, +0.6 points per year [95% CI, 0.2-1.0]). Off-label EVAR frequency was unchanged (mean, 39%) but intraoperative complications decreased (0.5% per year [95% CI, 0.2-0.9]). OAR complexity increased reflecting greater suprarenal cross-clamp rates (0.4% per year [95% CI, 0.1-0.8]) and blood loss (33 mL/y [95% CI, 19-47]). In-hospital complications decreased for elective (0.7% per year [95% CI, 0.4-0.9]) and nonelective EVAR (1.7% per year [95% CI, 1.1-2.3]) but not OAR (mean, 42%). A 30-day mortality was unchanged for both elective OAR (mean, 4%) and EVAR (mean, 1%). Among nonelective OARs, an increase in both 30-day (0.8% per year [95% CI, 0.1-1.5]) and 1-year mortality (0.8% per year [95% CI, 0.3-1.6]) was observed. Postoperative EVAR surveillance acquisition decreased (67%→49%), while 1-year mortality among patients without imaging was 4-fold greater (9.2% versus imaging, 2.0%; odds ratio, 4.1 [95% CI, 3.8-4.3]; P<0.0001).

CONCLUSIONS

There has been an increase in EVAR and a corresponding reduction in OAR across the United States, despite established concerns surrounding guideline adherence, reintervention, follow-up, and cost. Although EVAR morbidity has declined, OAR complication rates remain unchanged and unexpectedly high. Opportunities remain for improving AAA care delivery, patient and procedure selection, guideline compliance, and surveillance.

2023 Update on Vascular Anesthesia

The authors thank thank the editors for this opportunity to review the recent literature on vascular surgery and anesthesia and provide this clinical update. The last in a series of updates on this topic was published in 2019.1 This review explores evolving discussions and current trends related to vascular surgery and anesthesia that have been published since then. The focus is on the major points discussed in the recent literature in the following areas: carotid artery surgery, infrarenal aortic surgery, peripheral vascular surgery, and the preoperative evaluation of vascular surgical patients.

Center-level outcomes following elective fenestrated endovascular aortic aneurysm repair in the Vascular Quality Initiative database

OBJECTIVE

Hospital volume is associated with mortality after open aortic aneurysm repair. Fenestrated and branched endovascular aortic repair (B-FEVAR) has been increasingly used for repair of complex thoracoabdominal and juxtarenal aneurysms, but evidence of a center-volume relationship is limited. We aimed to measure the association of center volume with in-hospital mortality, postoperative outcomes, and 1-year survival following B-FEVAR.

METHODS

Patients undergoing elective endovascular thoracoabdominal and complex abdominal aneurysm repair with branch intervention (2014-2021) listed within the national Vascular Quality Initiative Thoracic Endovascular Aortic Repair/Complex EVAR database were analyzed. Centers were grouped into quartiles by mean annual procedure volume. Multivariable regression was used to evaluate the effect of center volume on in-hospital mortality adjusting for baseline and procedural characteristics. Kaplan-Meier estimation, log rank test, and mixed effects Cox regression were used to evaluate 1-year survival.

RESULTS

A total of 4302 adult elective F-BEVAR procedures were identified at a total of 163 centers. In-hospital mortality did not differ by hospital volume (quartile [Q]1 = 35/1059 [3.3%]; Q2 = 30/1063 [2.8%]; Q3 = 33/1120 [2.9%]; and Q4 = 44/1060 [4.2%]; P = .308). The high volume group had a higher rate of major complication (Q1 = 14.9%; Q2 = 12.8%; Q3 = 13.3%; and Q4 = 20.1%; adjusted P < .001). Physician-modified grafts were more frequently employed in high-volume centers (Q1 = 4.5%; Q2 = 18.7%; Q3 = 11.3%; and Q4 = 19.2%; P < .001), with a decreased incidence of any endoleak noted at the end of the procedure (Q1 = 34.9%; Q2 = 32.8%; Q3 = 30.0%; and Q4 = 29.0%; P = .003). In the multivariable analysis, in-hospital mortality was not associated with center volume, comparing very low volume to medium- and high-volume centers (odds ratio [95% confidence interval] vs Q4: Q1 = 1.1 [0.6-1.9], Q2 = 0.6 [0.4-1.1], and Q3 = 0.9 [0.5-1.5]; all P > .05). No significant difference was found in 1-year survival between center volume groups.

CONCLUSIONS

In-hospital mortality is not associated with procedure volume within centers performing complex endovascular aortic repair. However, complication rates and endoleak may be associated with procedure volume. Long-term outcomes by annualized procedure volume, specifically graft durability and sac expansion, should be investigated.

Intraoperative Predictors and Proposal for a Novel Prognostic Risk Score for In-Hospital Mortality after Open Repair of Ruptured Abdominal Aortic Aneurysms (SPARTAN Score)

(1) Background: Several mortality risk scores have been developed to predict mortality in ruptured abdominal aortic aneurysms (rAAAs), but none focused on intraoperative factors. The aim of this study is to identify intraoperative variables affecting in-hospital mortality after open repair and develop a novel prognostic risk score. (2) Methods: The analysis of a retrospectively maintained dataset identified patients who underwent open repair for rAAA from January 2007 to October 2023 in three Italian tertiary referral centers. Multinomial logistic regression was used to calculate the association between intraoperative variables and perioperative mortality. Independent intraoperative factors were used to create a prognostic score. (3) Results: In total, 316 patients with a mean age of 77.3 (SD ± 8.5) were included. In-hospital mortality rate was 30.7%. Hemoperitoneum (p < 0.001), suprarenal clamping (p = 0.001), and operation times of >240 min (p = 0.008) were negative predictors of perioperative mortality, while the patency of at least one hypogastric artery had a protective role (p = 0.008). Numerical values were assigned to each variable based on the respective odds ratio to create a risk stratification for in-hospital mortality. (4) Conclusions: rAAA represents a major cause of mortality. Intraoperative variables are essential to estimate patients' risk in surgically treated patients. A prognostic risk score based on these factors alone may be useful to predict in-hospital mortality after open repair.

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

Conflicting European and North American Society Abdominal Aortic Aneurysm (AAA) Volume Guidelines Differentially Discriminate Peri-operative Mortality After Elective Open AAA Repair

OBJECTIVE

The European Society for Vascular Surgery (ESVS) guidelines endorse a minimum abdominal aortic aneurysm (AAA) repair volume of 20 open (OAR) and or endovascular (EVAR) AAA repair procedures per year as a proxy for high quality care. In contrast, the Society for Vascular Surgery (SVS) espouses 10 exclusively OARs per year. Given the differences in these volume standards and definitions, debate persists regarding surgeon credentialing and healthcare resource allocation. This analysis aimed to determine which society endorsed volume benchmark better discriminates OAR mortality.

METHODS

A retrospective national registry based cohort analysis. Patients undergoing elective OAR were compared between centres meeting either ESVS (≥ 20 AAA procedures/year) or SVS (≥ 10 OARs/year) volume thresholds within the Vascular Quality Initiative (2010 - 2020). The primary outcome was in hospital death. Logistic regression was used for risk adjusted comparisons.

RESULTS

A total of 8 761 OARs were performed at 193 US centres, and the median (IQR) volume was 6.6 (3.3, 9.9) OARs/year. When applying the SVS centre volume definition, the proportion of centres meeting ESVS and SVS minimum case thresholds was 12% (n = 22) and 25% (n = 48), respectively. The absolute mortality difference was 0.3% between centres performing ≥ 20 vs. ≥ 10 OARs/year (2.6% vs. 2.9%; p = .51). There was an incremental association between OAR volume and crude mortality rate; however, this absolute difference between lower and higher thresholds was only 0.2%/procedure (OR 0.98, 95% CI 0.97 - 0.99; p < .001). Moreover, no difference in risk adjusted mortality was detected between volume standards (≥ 10 vs. ≥ 20; p = .78). In sub-analysis, the ESVS ≥ 20 total composite AAA repair volume threshold was not associated with mortality (p = .17); however, increasing the proportion of OAR cases making up the total annual AAA centre volume inversely correlated with mortality (p = .008).

CONCLUSION

It appears that the SVS endorsed AAA centre volume threshold using exclusively OAR had a modest ability to discriminate peri-operative mortality outcomes and was superior to the current composite ESVS volume guideline in differentiating centre performance. These findings raise questions regarding the clinical validity of using EVAR as a volume proxy for OAR.

Analysis of Early Death after Elective Open Abdominal Aortic Aneurysm Repair

BACKGROUND

Mortality after open abdominal aortic aneurysm repair is a quality measure and early death may represent a technical complication or poor patient selection. Our objective was to analyze patients who died in the hospital within postoperative day (POD) 0-2 after elective abdominal aortic aneurysm repair.

METHODS

The Vascular Quality Initiative was queried from 2003-2019 for elective open abdominal aortic aneurysm repairs. Operations were categorized as in-hospital death on POD 0-2 (POD 0-2 Death), in-hospital death beyond POD 2 (POD ≥3 Death), and those alive at discharge. Univariable and multivariable analyses were performed.

RESULTS

There were 7,592 elective open abdominal aortic aneurysm repairs with 61 (0.8%) POD 0-2 Death, 156 (2.1%) POD ≥3 Death, and 7,375 (97.1%) alive at discharge. Overall, median age was 70 years and 73.6% were male. Iliac aneurysm repair and surgical approach (anterior/retroperitoneal) were similar among groups. POD 0-2 Death, compared to POD ≥3 Death and those alive at discharge, had the longest renal/visceral ischemia time, more commonly had proximal clamp placement above both renal arteries, an aortic distal anastomosis, longest operative time, and largest estimated blood loss (all P < 0.05). Postoperative vasopressor usage, myocardial infarction, stroke, and return to the operating room were most frequent in POD 0-2 Death and extubation in the operating room was least frequent (all P < 0.001). Postoperative bowel ischemia and renal failure occurred most commonly among POD ≥3 Death (all P < 0.001).On multivariable analysis, POD 0-2 Death was associated with congestive heart failure, prior peripheral vascular intervention, female sex, preoperative aspirin use, lower center volume quartile, renal/visceral ischemia time, estimated blood loss, and older age (all P < 0.05).

CONCLUSIONS

POD 0-2 Death was associated with comorbidities, center volume, renal/visceral ischemia time, and estimated blood loss. Referral to high-volume aortic centers could improve outcomes.

Risk Prediction Models for Peri-Operative Mortality in Patients Undergoing Major Vascular Surgery with Particular Focus on Ruptured Abdominal Aortic Aneurysms: A Scoping Review

PURPOSE

The present scoping review aims to describe and analyze available clinical data on the most commonly reported risk prediction indices in vascular surgery for perioperative mortality, with a particular focus on ruptured abdominal aortic aneurysm (rAAA).

MATERIALS AND METHODS

A scoping review following the PRISMA Protocols Extension for Scoping Reviews was performed. Available full-text studies published in English in PubMed, Cochrane and EMBASE databases (last queried, 30 March 2023) were systematically reviewed and analyzed. The Population, Intervention, Comparison, Outcome (PICO) framework used to construct the search strings was the following: in patients with aortic pathologies, in particular rAAA (population), undergoing open or endovascular surgery (intervention), what different risk prediction models exist (comparison), and how well do they predict post-operative mortality (outcomes)?

RESULTS

The literature search and screening of all relevant abstracts revealed a total of 56 studies in the final qualitative synthesis. The main findings of the scoping review, grouped by the risk score that was investigated in the original studies, were synthetized without performing any formal meta-analysis. A total of nine risk scores for major vascular surgery or elective AAA, and 10 scores focusing on rAAA, were identified. Whilst there were several validation studies suggesting that most risk scores performed adequately in the setting of rAAA, none reached 100% accuracy. The Glasgow aneurysm score, ERAS and Vancouver score risk scores were more frequently included in validation studies and were more often used in secondary studies. Unfortunately, the published literature presents a heterogenicity of results in the validation studies comparing the different risk scores. To date, no risk score has been endorsed by any of the vascular surgery societies.

CONCLUSIONS

The use of risk scores in any complex surgery can have multiple advantages, especially when dealing with emergent cases, since they can inform perioperative decision making, patient and family discussions, and post hoc case-mix adjustments. Although a variety of different rAAA risk prediction tools have been published to date, none are superior to others based on this review. The heterogeneity of the variables used in the different scores impairs comparative analysis which represents a major limitation to understanding which risk score may be the "best" in contemporary practice. Future developments in artificial intelligence may further assist surgical decision making in predicting post-operative adverse events.

Incidence, predictors, and prognostic impact of in-hospital serious adverse events in patients ≥75 years of age undergoing elective endovascular aneurysm repair

BACKGROUND

This study sought to identify the factors associated with the occurrence of in-hospital serious adverse events after elective endovascular aortic repair (EVAR) in older patients within the Global Registry for Endovascular Aortic Treatment.

METHODS

Consecutive patients ages ≥75 years who received GORE EXCLUDER AAA Endoprosthesis (W.L. Gore & Associates, Inc, Flagstaff, AZ) for elective EVAR. Based on the age at index elective EVAR, patients were categorized into 3 groups for subsequent analyses: those ages 75 to 79, 80 to 84, and ≥85 years. The primary end points for this study were the incidence of serious adverse events and all-cause mortality. In-hospital complications were defined according to the International Organization for Standardization 14155 standard (https://www.iso.org/standard/71690.html) and considered serious adverse events if they led to any of the following: (1) a life-threatening illness or injury, (2) a permanent impairment of a body structure or a body function, (3) in-patient or prolonged hospitalization, or (4) medical or surgical intervention to prevent life-threatening illness or injury or permanent impairment to a body structure or a body function.

RESULTS

Overall, 1,333 older patients (ages 75-79: n = 601; 80-84: n = 474; and ≥85: n = 258) underwent elective EVAR in the Global Registry for Endovascular Aortic Treatment data set and were included in the present analysis. In total, 12 patients (0.9%) died perioperatively, and 103 patients (7.7%) experienced ≥1 in-hospital serious adverse event, with 18 patients (1.3%) experiencing >1 in-hospital complications. No significant differences were seen between the age groups in the rates of in-hospital serious adverse events (7.3% vs 8.2% vs 7.8%; P = .86). In logistic regression analysis, a history of chronic obstructive pulmonary disease (odds ratio = 2.014; 95% confidence interval, 1.215-3.340; P = .006) and prior requirement for dialysis (odds ratio = 4.655; 95% confidence interval, 1.087-19.928; P = .038) resulted as predictors for occurrence of in-hospital serious adverse events. In the whole cohort, the 5-year survival was 63% for patients who did not experience any in-hospital serious adverse events compared with 51% for those who experienced any complications (P = .003). Using multivariable Cox proportional hazards models, it was found that the occurrence of in-hospital serious adverse events (hazard ratio = 6.2; 95% confidence interval, 1.8-21.317; P = .003) and being underweight (hazard ratio = 7.0; 95% confidence interval, 1.371-35.783; P = .019) were the only independent predictors of death in ≤30 days from the initial intervention. Although age did not independently affect the risk for all-cause mortality in ≤180 days after the initial intervention, increasing age was associated with a higher risk for long-term death (ie, ≥181 days from index elective EVAR) in the multivariable analysis (ages 75-79: hazard ratio = 0.379; 95% confidence interval, 0.281-0.512; P < .001; and 80-84: hazard ratio = 0.562; 95% confidence interval, 0.419-0.754; P < .001).

CONCLUSION

After elective EVAR in older patients (ie, ≥75 years), the occurrence of in-hospital serious adverse events appears to increase the risk of death, particularly in ≤180 days after the initial elective EVAR intervention, and might be related to patient baseline characteristics, including history of pulmonary and renal disease.

Center Volume and Failure to Rescue after Open or Endovascular Repair of Ruptured Abdominal Aortic Aneurysms

BACKGROUND

The correlation between center volume and elective abdominal aortic aneurysm(AAA) repair outcomes is well established; however, these effects for either endovascular(EVAR) or open(OAR) repair of ruptured AAA(rAAA) remains unclear. Notably, the capacity to either avert or manage complications associated with postoperative mortality is an important cause of outcome disparities following elective procedures; however, there is a paucity of data surrounding non-elective presentations. Therefore, the purpose of this analysis was to describe the association between annual center volume, complications, and failure to rescue(FtR) after EVAR and OAR of rAAA.

METHODS

All consecutive endovascular and open rAAA repairs from 2010-2020 in the Vascular Quality Initiative were examined. Annual center volume(procedures/year per center) was grouped into quartiles: EVAR-Q1[<14](3.4%), Q2[14-23](12.8%), Q3[24-37](24.7%), Q4[>38](59.1%); OAR-Q1[<3](5.4%), Q2[4-6](12.8%), Q3[7-10](22.7%), Q4[>10](59.1%). The primary end-point was FtR, defined as in-hospital death after experiencing one of six major complications(cardiac, renal, respiratory, stroke, bleeding, colonic ischemia). Risk-adjusted analyses for inter-group comparisons was completed using multivariable logistic regression.

RESULTS

The unadjusted in-hospital death rate was 16.5% and 28.9% for EVAR and OAR, respectively. Complications occurred in 45% of EVAR(n=1,439/3,188) and 70% of OAR(n=1,366/1,961) patients with corresponding FtR rates of 14%(EVAR) and 26%(OAR). For OAR, Q4-centers had a 43% lower FtR risk(OR 0.57, 95%CI 0.4-0.9;p=.017) compared to Q1 centers. Centers performing >5 OARs/year had a 43% lower risk(OR 0.57, 95%CI 0.4-0.7;p<.001) of FtR and this decreased 4% for each additional 5 procedures performed annually(95%CI .93-.991;p=.013). However, there was no significant relationship between center volume and FtR after EVAR. The risk of FtR was strongly associated with a greater number of complications for both procedures(OR multiplied by 6.5 for EVAR and 1.5 for OAR for each additional complication;p<.0001). Among OAR patients with a single recorded complication, return to the operating room for bleeding had highest risk of in-hospital mortality(OR 4.1, 95%CI 1.1-4.8;p=.034), while no specific type of complication increased FtR risk after EVAR.

CONCLUSIONS

FtR occurs commonly after EVAR and OAR of rAAA within VQI centers. Importantly, increasing center volume was associated with reduced FtR risk after OAR but not EVAR. Complication pattern and frequency predicted FTR after either repair strategy. For stable patients, especially those deemed anatomically ineligible for EVAR, these findings emphasize the need to improve coordination of regional referral networks that centralize rAAAs to high-volume centers. Moreover, hospitals that treat rAAA should invest resources that develop protocols targeting specific complications to mitigate risk of preventable postoperative death.