International Trends in Patient Selection for Elective Endovascular Aneurysm Repair: Sicker Patients with Safer Anatomy Leading to Improved 1-Year Survival

Decreasing Trends in Reintervention and Readmission After Endovascular Aneurysm Repair in a Multiregional Implant Registry

OBJECTIVES

As endovascular aortic aneurysm repair (EVAR) matures into its third decade, measures such as long-term reintervention and readmission have become a focus of quality improvement efforts. Within a large United States integrated healthcare system, we describe time trends in the rates of long-term reinterventions utilization measures.

METHODS

Data from a US multiregional EVAR registry was used to perform a descriptive study of 3,891 adults who underwent conventional infrarenal EVAR for infrarenal abdominal aortic aneurysm between 2010 to 2019. Three-year follow-up was 96.7%. Outcomes included 1-, 3-, and 5-year graft revision (defined as a procedure involving placement of a new endograft component), secondary interventions (defined as a procedure necessary for maintenance of EVAR integrity, e.g., coil embolization and balloon angioplasty/stenting), conversion to open, interventions for type II endoleaks alone, and 90-day readmission. Crude cause-specific reintervention probabilities were calculated by operative year using the Aalen-Johansen estimator, with death as a competing risk and December 31, 2020 as the study end date.

RESULTS

Excluding interventions for type II endoleak alone, 1-year secondary intervention incidence decreased from 5.9% for EVARs in 2010 to 2.0% in 2019 (p<0.001) and 3-year incidence decreased from 7.2% to 3.6% from 2010 to 2017 (p=0.03). The 3-year incidences of graft revision (mean incidence 3.4%) and conversion to open remained fairly stable (mean incidence 0.6%) over time. The 3-year incidence of interventions for type II endoleak alone also decreased from 3.4% in 2010 to 0.7% in 2017 (p=0.01). 90-day readmission rates decreased from 19.3% for index EVAR in 2010 to 9.2% in 2019 (p=0.03).

CONCLUSIONS

Comprehensive data from a multiregional healthcare system demonstrates decreasing long-term secondary intervention and readmission rates over time in patients undergoing EVAR. These trends are not explained by evolving management of type II endoleaks and suggest improving graft durability, patient selection or surgical technique. Further study is needed to define implant and anatomic predictors of different types of long-term reintervention.

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.

Update of a Model to Predict Outcomes after Endovascular Aneurysm Repair

BACKGROUND

Risk assessment models must be continuously validated and updated to ensure that predictions remain valid. Here, the Endovascular Aneurysm Repair Risk Assessment Model, developed in 2008, is updated and improved.

METHODS

We used prospectively collected data from Australian patients who underwent elective endovascular aneurysm repair between 2009 and 2013 (n = 695). Data were provided by treating surgeons and the National Death Index. Key outcomes were early and midterm survival, early complications (endoleak, operative, and graft-related) and late complications (endoleak and graft-related). Multinomial logistic regression determined which preoperative variables best predicted each outcome. Area under Receiver Operating Characteristic curve (AUROC), model P-value and internal validation statistics were used to select the best model.

RESULTS

Ten preoperative variables were included in the modeling for 10 key outcomes. The most valid outcomes with AUROC>0.7 were 1- and 3-year survival, 30 and 90-day mortality, early and late endoleak (types I, III and IV) and type II endoleak (with an increase in sac size ≥5 mm). The 10 preoperative variables that contributed to outcome models were self-reported fitness, American Society of Anesthesiologists physical status score, history of stroke/transient ischemic attack, age, aneurysm angle, infrarenal neck length, white cell count, respiratory assessment, diabetes and statin therapy. Fitness alone statistically significantly predicted 30 and 90-day deaths better than any other preoperative variable; achieving high AUROCs (0.78 and 0.80), and high odds ratios (12.8 [95% CI: 1.5-110.4] and 18.1 [95% CI: 2.2-149]).

CONCLUSIONS

An updated interactive predictive model of outcomes after endovascular aneurysm repair has been created. Many of the variables used in the 2008 model continued to be significant, however, new variables including fitness and respiratory assessment, improved the model. The new model uses variables routinely collected preoperatively, and hence can better support surgeon-patient discussions prior to operation. Informing patients of potential risks or likely outcomes following elective surgery can assist with preoperative shared decision-making.

Descriptive and follow-up study of patients treated surgically for abdominal aortic aneurysm at tertiary hospitals in Spain

BACKGROUND

The aim of this study was to assess potential variability in the clinical characteristics and treatment of patients undergoing elective surgery for abdominal aortic aneurysm (AAA) across five hospitals in Spain.

METHODS

Multicenter, retrospective cohort study of patients diagnosed with AAA and treated with open surgical repair (OSR) or endovascular aneurysm repair (EVAR). We evaluated clinical and demographic variables, including comorbidity (Charlson Comorbidity Index [CCI]); anatomic characteristics; surgical risk (ASA Score); aneurysm characteristics; and in-hospital and overall mortality. All patients were followed for three years.

RESULTS

A total of 186 patients were included, mean age 72.5 (standard deviation [SD], 8.4), mean CCI 2.04 (SD, 1.9). The surgical technique was EVAR in 46.8% of cases (N.=87) and OSR in 53.2% (N.=99). The in-hospital mortality rate was 2.2%, with no differences between groups. The overall mortality rate during follow-up (mean, 2.9 years) was 24.1% for EVAR versus 8.1% for the OSR group (odds ratio [OR], 3.62; 95% confidence interval [CI], 3.60-3.64; P=0.004). EVAR was the only independent risk factor for mortality (OR, 3.89; 95% CI: 3.87-3.92; P=0.004). Inter-center variability in the type of surgery was high, with EVAR accounting for 19.4% to 75% of the surgical procedures, depending on the treating center (P<0.001).

CONCLUSIONS

In this study the in-hospital mortality rates for elective EVAR and OSR were similar. However, after the follow-up, patients who underwent EVAR had a three-fold greater mortality rate than those treated with OSR. There was substantial inter-hospital variability, underscoring the need to standardize treatment selection in patients who undergo elective surgery for AAA repair.

Variation in the choice of elective surgical procedure for abdominal aortic aneurysm in Spain

Objective

The two main surgical treatments for abdominal aortic aneurysm (AAA) are open surgical repair (OSR) and endovascular aneurysm repair (EVAR). The aim of this study was to analyze variation among Spanish hospitals in the use of OSR or EVAR for AAA. A secondary aim was to assess changes in preferences for these two procedures over time.

Methods

This was a retrospective longitudinal study based on discharge data from public hospitals in Spain during 2002–2012. Patient inclusion criteria were: age >18 years, elective admission, primary diagnosis of unruptured AAA, and surgical treatment with OSR or EVAR. The characteristics of the treating center, patients, and in-hospital mortality were recorded.

Results

We included 16,737 patients from 114 hospitals; 6,809 (40.7%) underwent EVAR and 9,928 (59.3%) underwent OSR. The total volume of surgeries increased throughout the period, and the probability that any given procedure was EVAR increased by 20% per year (OR 1.20, P<0.001). The volume and distribution of the two procedures varied highly across the participating hospitals. Overall, in-hospital mortality rate was 3.6% and it decreased during the study period (5.3% in 2002 and 3.2% in 2012), mainly due to a decrease in OSR-related mortality, despite a slight increase in EVAR-related mortality. Hospitals with higher surgical volumes were more likely to use EVAR and have lower in-hospital mortality rates.

Conclusion

This study reveals high variability in the surgical treatment of unruptured AAA across Spanish hospitals. The number of interventions has increased in recent years, with EVAR accounting for a growing percentage of these surgical procedures. Overall in-hospital mortality rates decreased significantly during this period, mainly due to lower mortality among patients undergoing OSR. In-hospital mortality rates were lower in higher-volume centers, regardless of the surgical approach used. Further research on variability and appropriateness of surgical management of AAA is required to assess the suitability of concentrating elective AAA repair in more experienced centers to potentially achieve better outcomes.

Circulating biomarkers are not associated with endoleaks after endovascular repair of abdominal aortic aneurysms

OBJECTIVE

Endoleak is a common complication of endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) but can be detected only through prolonged follow-up with repeated aortic imaging. This study examined the potential for circulating matrix metalloproteinase 9 (MMP9), osteoprotegerin (OPG), D-dimer, homocysteine (HCY), and C-reactive protein (CRP) to act as diagnostic markers for endoleak in AAA patients undergoing elective EVAR.

METHODS

Linear mixed-effects models were constructed to assess differences in AAA diameter after EVAR between groups of patients who did and did not develop endoleak during follow-up, adjusting for potential confounders. Circulating MMP9, OPG, D-dimer, HCY, and CRP concentrations were measured in preoperative and postoperative plasma samples. The association of these markers with endoleak diagnosis was assessed using linear mixed effects adjusted as before. The potential for each marker to diagnose endoleak was assessed using receiver operating characteristic curves.

RESULTS

Seventy-five patients were included in the study, 24 of whom developed an endoleak during follow-up. Patients with an endoleak had significantly larger AAA sac diameters than those who did not have an endoleak. None of the assessed markers showed a significant association with endoleak. This was confirmed through receiver operating characteristic curve analyses indicating poor diagnostic ability for all markers.

CONCLUSIONS

Circulating concentrations of MMP9, OPG, D-dimer, HCY, and CRP were not associated with endoleak in patients undergoing EVAR in this study.

Risk factors for ischaemic colitis after surgery for abdominal aortic aneurysm: a systematic review and observational meta-analysis

BACKGROUND

Ischaemic colitis is an infrequent but serious complication following repair of abdominal aortic aneurysm (AAA), with high mortality rates. This systematic review set out to identify risk factors for the development of ischaemic colitis after AAA surgery.

METHODS

A systematic search of the MEDLINE, EMBASE and CINAHL databases was performed. This search was limited to studies published in the English language after 1990. Abstracts were screened by two authors. Eligible studies were obtained as full text for further examination. Data was extracted by two authors, and any disputes were resolved via consensus. Extracted data was pooled using Mantel-Haenszel random effects models. Bias was assessed using two Cochrane-approved tools. Effect sizes are expressed as relative risk ratios alongside the 95 % confidence interval. Statistical significance was defined at the level of p < 0.05.

RESULTS

From 388 studies identified in the initial search, 33 articles were included in the final synthesis and analysis. Risk factors were grouped into patient (female gender, disease severity) and operative factors (peri-procedural hypotension, operative modality). The risk of ischaemic colitis was significantly higher when undergoing emergency repair versus elective (risk ratio (RR) 7.36, 3.08 to 17.58, p < 0.001). Endovascular repair reduced the likelihood of ischaemic colitis (RR 0.22, 0.12 to 0.39, p < 0.001).

DISCUSSION

The quality of published evidence on this subject is poor with many retrospective datasets and inconsistent reporting across studies. Despite this, emergency presentation and open repair should prompt close monitoring for the development of IC.

Chimney Grafts in Aortic Stent Grafting: Hazardous or Useful Technique? Systematic Review of Current Data

BACKGROUND

The chimney graft (CG) technique was introduced to rescue accidentally covered aortic branches during aortic endovascular repair. It extends the sealing zone. There is concern about "gutter" type I endoleak (EL-I) and about the durability of CGs. The aim of the present report was to analyze the rapidly increasing existing data.

METHODS

A search was performed (PRISMA criteria) for all studies of visceral and thoracic/arch chimney grafts. Technical and clinical details and outcome were assessed.

RESULTS

The present review includes 831 patients who underwent EVAR/TEVAR (endovascular aneurysm repair/thoracic endovascular aneurysm repair) with one or more chimney, periscope, or sandwich grafts. For aortic visceral vessels 517 patients received 911 visceral CGs and 314 patients received 364 arch CGs. Most procedures (81% visceral and 69% arch CGs) were elective. Thirty day mortality was 4% for both groups. The rate of early EL-I was 13% (visceral CGs) and 11% (arch CGs). Most EL-I were handled conservatively (observation: 70% for visceral CG and 45% for arch CG). Early CG patency was high (97-99%) and remained high during follow up (median 17 months). Late (after 30 days) EL-I was reported in nine visceral (2%) and 12 arch (4%) CG cases. Few other late complications were reported, but those losing a kidney at the initial repair seemed to have a high risk of requiring permanent hemodialysis.

CONCLUSION

Increasing amounts of data support the benefit of visceral and arch chimney graft techniques. In particular, the low early mortality and complication rates and high long-term patency seem advantageous; however, the majority of cases have been treated electively, and there is a high risk of bias in all studies. Mid- to long-term data suggest few late complications, except in cases where one renal artery was sacrificed. The CG technique is valuable for complex urgent patients and needs further documentation for other patient groups.