Comparative effectiveness of endovascular versus open repair of ruptured abdominal aortic aneurysm in the Medicare population

Technical challenges during emergent endovascular aneurysm repair with the ALTO system

INTRODUCTION

Ruptured abdominal aortic aneurysms (AAAs) pose an immediate threat for patient's life and endovascular repair (EVAR) is currently the preferred treatment modality in the presence of suitable anatomy. This is determined based on the requirements of each endograft as described in the instructions for use (IFU). The new ALTO system (Endologix, Irvin, CA, U.S.A.), can accommodate a great range of anatomies such as short necks and/or narrow access, but its unique design requires specific technical modifications during treatment of ruptured AAAs.

AREAS COVERED

The standard double balloon technique has long been described and it is used to provide circulatory support during EVAR for ruptured AAA. While this technique is straightforward with the use of endografts with a traditional design, this would not be the case if one uses the ALTO system. In that case specific maneuvers would be required to treat AAA patients in an acute setting.

EXPERT OPINION

The ALTO system although being able to treat AAAs with adverse anatomy, it may not be appropriate during treatment of ruptured AAA patients with profound hemodynamic instability. A careful evaluation of the individual's patient anatomy and hemodynamic condition is mandatory in order to decide the best endograft for each case.

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.

Treatment Outcomes of Patients With Ruptured Abdominal Aortic Aneurysms

BACKGROUND

Ruptured abdominal aortic aneurysm (rAAA) is a serious complication of abdominal aortic aneurysm associated with high operative mortality and morbidity rates. The present study evaluated the perioperative and long-term outcomes of Korean patients with rAAA based on national health insurance claims data.

METHODS

The National Health Insurance Service (NHIS) database was searched retrospectively to identify patients with rAAA who underwent endovascular aneurysm repair (EVAR) and open surgical repair (OSR) from 2009 to 2018. Perioperative (≤ 30 days), early postoperative (≤ 3 month), and long-term (> 3 month) survival, reinterventions, and complications were assessed.

RESULTS

The search identified 1,034 patients with rAAA, including 594 who underwent EVAR and 440 who underwent OSR. When the study period was divided into two, the total numbers of patients with rAAA, patients who underwent EVAR, and octogenarians were higher during the second half. The perioperative mortality rate was 29.8% in the EVAR and 35.0% in the OSR group (P = 0.028). Hartmann's procedure for bowel infarction was performed more frequently in the OSR than in the EVAR group (adjusted odds ratio, 6.28; 95% confidence interval [CI], 2.33-21.84; P = 0.001), but other complication rates did not differ significantly. All-cause mortality during the entire observation period did not differ significantly in the EVAR and OSR groups (adjusted hazard ratio, 1.17; 95% CI, 0.98-1.41; P = 0.087). Abdominal aortic aneurysm-related reintervention rate was significantly lower in the OSR group (adjusted hazard ratio, 0.31; 95% CI, 0.14-0.70; P = 0.005).

CONCLUSION

Although EVAR showed somewhat superior perioperative outcomes for rAAA, the long-term outcomes of EVAR after excluding initial 3 months were significantly worse than OSR. When anatomically feasible for both treatments, the perioperative mortality risk and reasonable prospects of long-term survival should be considered in rAAA.

Infrarenal Abdominal Aortic Aneurysm

Abdominal aortic aneurysms are found in up to 6% of men and 1.7% of women over the age of 65 years and are usually asymptomatic. The natural history of aortic aneurysms is continued dilation leading to rupture, which is associated with an overall 80% mortality. Of the patients with ruptured aneurysms that undergo intervention, half will not survive their hospitalization. Reduction in aneurysm mortality is therefore achieved by prophylactic repair during the asymptomatic period. On a population-based level, this is supported by abdominal aortic aneurysm screening programs. Approximately 60% of abdominal aortic aneurysms are confined to the infrarenal portion of the aorta and are amenable to repair with off-the-shelf endovascular devices. Endovascular techniques have now replaced open surgery as the primary modality for aneurysm repair.

[Endovascular aneurysm repair (EVAR) : Update D]

BACKGROUND

Abdominal aortic aneurysms can either be treated by open surgery or endovascular repair. In both cases, prostheses are implanted to prevent potentially lethal aortic ruptures.

OBJECTIVES

Studies seeking to identify the optimal treatment came to diverging conclusions. The goal of this article is to shed light on the discussion of which treatment option is to be preferred.

MATERIALS AND METHODS

This article summarizes the relevant studies on elective and emergency abdominal aortic aneurysm repair. The presented studies are discussed, and results are interpreted and compared.

RESULTS

While most studies indicate lower short-term mortality rates in endovascular aneurysm repair (EVAR), mortality rates converged in multiple trials and even showed a lower mortality rate for open repair in mid-term analyses. Most recent studies indicate long-term equivalence in terms of mortality and a higher rate of secondary interventions in EVAR patients.

CONCLUSIONS

The current body of literature indicates no real advantage of one therapy over another. The choice of therapy should depend on anatomic, clinical, and logistic criteria.

New tools to reduce radiation exposure during aortic endovascular procedures

INTRODUCTION

The evolution of endovascular surgery over the past 30 years has made it possible to treat increasingly complex vascular pathologies with an endovascular method. Although this generally speeds up the patient's recovery, the risks of health problems caused by long-term exposure to radioactive radiation increase. This warrants the demand for radiation-reducing tools to reduce radiation exposure during these procedures.

AREAS COVERED

For this systematic review Pubmed, Embase and Cochrane library databases were searched on 28 December 2021 to provide an overview of tools that are currently used or have the potential to contribute to reducing radiation exposure during endovascular aortic procedures. In addition, an overview is presented of radiation characteristics of clinical studies comparing a (potential) radiation-reducing device with conventional fluoroscopy use.

EXPERT OPINION

Radiation-reducing instruments such as fiber optic shape sensing or electromagnetic tracking devices offer the possibility to further reduce or even eliminate the use of radiation during endovascular procedures. In an era of increasing endovascular interventional complexity and awareness of the health risks of long-term radiation exposure, the use of these technologies could have a major impact on an ongoing challenge to move toward radiation-free endovascular surgery.

Derivation and Validation of a Risk Score for Abdominal Compartment Syndrome after Endovascular Aneurysm Repair for Ruptured Abdominal Aortic Aneurysms

BACKGROUND

Abdominal compartment syndrome (ACoS) is a devastating complication after endovascular aneurysm repair for ruptured abdominal aortic aneurysms (rEVAR). This study sought to develop a risk score for ACoS to identify patients who would benefit from early decompressive laparotomy.

METHODS

Model derivation was performed with VQI data for rEVAR from 2013-2020. The primary outcome was evacuation of abdominal hematoma. Multivariable logistic regression was used to create and validate a scoring system to predict ACoS. The model was validated using institutional data for rEVAR from 1998-2019.

RESULTS

The derivation cohort included 2,310 patients with rEVAR. Abdominal hematoma evacuation occurred in 265 patients (11.5%). Factors associated with abdominal hematoma evacuation on multivariable analysis included transfer from an outside hospital, preoperative creatinine ≥1.4 mg/dl, preoperative systolic blood pressure ≤85 mmHg, preoperative altered mental status, ≥3.0 liters intraoperative crystalloid, and ≥4 units of red blood cells transfused intraoperatively. The validation cohort consisted of 67 rEVAR; ACoS occurred in 8 patients (11.9%). The c-statistic was 0.84 in the derivation and 0.87 in the validation cohort, while Hosmer-Lemeshow was p= 0.15 in the derivation and 0.84 in the validation cohorts, suggesting good model discrimination and calibration. Points were applied based on β-coefficients to produce a risk score ranging from -1 to 13. A cutoff of risk score ≥8 resulted in a sensitivity and specificity of 87.5% and 83.1% for detecting patients with ACoS, respectively. ACoS conveyed a significantly higher mortality in both the derivation (ACoS: 49.8% vs No ACoS: 17.8%; p<0.001) and validation cohorts (ACoS: 75.0% vs No ACoS: 15.2%; p<0.001).

CONCLUSION

In patients with equivocal signs/symptoms of ACoS, this scoring system can be used to guide surgeons on when to perform decompressive laparotomy prior to leaving the operating room for rEVAR. Patients with a risk score ≥8 would benefit from decompressive laparotomy at index rEVAR.

A comparison of endovascular versus open repair for ruptured abdominal aortic aneurysm - Meta-analysis of propensity score-matched data

BACKGROUND

Optimal management of ruptured abdominal aortic aneurysms (rAAA) has been heavily debated in the literature. The aim of this review is to assess comparative outcomes from propensity-matched studies of endovascular versus open for rAAA.

METHODS

Electronic databases (MEDLINE and Embase) were searched in January 2021 using the Healthcare Databases Advanced Search interface. Eligible studies compared endovascular versus open repair for rAAA using propensity-matched cohorts. Pooled estimates of perioperative outcomes were calculated using odds ratio (OR) or mean difference (MD) and 95% confidence interval (CI) using the random-effects model. Time-to-event data meta-analysis was conducted using the inverse-variance method and reported as summary hazard ratio (HR) and associated 95% CI. The quality of evidence was graded using a system developed by the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) working group.

RESULTS

Six studies published between 2010 and 2020 were selected for qualitative and quantitative synthesis, reporting a total of 6731 patients. The odds of perioperative mortality after endovascular aneurysm repair (EVAR) were significantly lower than after open surgical repair (OSR) (OR 0.52, 95% CI 0.41-0.65). The hazard of overall mortality during follow-up was lower, although not significantly, after EVAR than after OSR (HR 0.79, 95% CI 0.62-1.01). The odds of acute kidney injury and early aneurysm-related reintervention were both significantly lower after EVAR than after OSR (OR 0.34, 95% CI 0.14-0.78 and OR 0.57, 95% CI 0.33-0.98, respectively). Patients treated with EVAR stayed in hospital for significantly less time than those treated with OSR (MD -5.13, 95% CI -7.94 to -2.32). The certainty of the body of evidence for perioperative mortality was low and for overall mortality was very low.

CONCLUSION

The evidence suggests that EVAR confers a significant benefit on perioperative mortality.

Time-to-event data meta-analysis of late outcomes of endovascular versus open repair for ruptured abdominal aortic aneurysms

OBJECTIVE

We investigated whether the well-documented perioperative survival advantage of emergency endovascular aneurysm repair (EVAR) compared with open repair would be sustained during follow-up.

METHODS

A systematic review conforming to the PRISMA (preferred reporting items for systematic reviews and meta-analyses) statement standards was conducted to identify studies that had reported the follow-up outcomes of endovascular vs open repair for ruptured abdominal aortic aneurysms. Electronic bibliographic sources (MEDLINE [medical literature analysis and retrieval system online], Embase [Excerpta Medica database], CINAHL [cumulative index to nursing and allied health literature], and CENTRAL [Cochrane central register of controlled trials]) were interrogated using the Healthcare Databases Advanced Search interface (National Institute for Health and Care Excellence, London, United Kingdom). A time-to-event data meta-analysis was performed using the inverse variance method, and the results were reported as summary hazard ratios (HRs) and associated 95% confidence intervals (CIs). Mixed effects regression was applied to investigate the outcome changes over time. The quality of the body of evidence was appraised using the GRADE (grades of recommendation, assessment, development, and evaluation) system.

RESULTS

Three randomized controlled trials and 22 observational studies reporting a total of 31,383 patients were included in the quantitative synthesis. The mean follow-up duration across the studies ranged from 232 days to 4.9 years. The overall all-cause mortality was significantly lower after EVAR than after open repair (HR, 0.79; 95% CI, 0.73-0.86). However, the postdischarge all-cause mortality was not significantly different (HR, 1.10; 95% CI, 0.85-1.43). The aneurysm-related mortality, which was reported by one randomized controlled trial, was not significantly different between EVAR and open repair (HR, 0.89; 95% CI, 0.69-1.15). Meta-regression showed the mortality difference in favor of EVAR was more pronounced in more recent studies (P = .069) and recently treated patients (P = .062). The certainty for the body of evidence for overall and postdischarge all-cause mortality was judged to be low and that for aneurysm-related mortality to be high.

CONCLUSIONS

EVAR showed a sustained mortality benefit during follow-up compared with open repair. A wider adoption of an endovascular-first strategy is justified.

Effect of endovascular therapy on the expression levels of serum T lymphocyte subsets, Notch1 and TACE proteins in patients with abdominal aortic aneurysm

To investigate the effect of endovascular therapy on the expression levels of serum T lymphocyte subsets, Notch1 and TACE proteins in patients with abdominal aortic aneurysm (AAA). A total of 84 AAA patients treated in the General Hospital of Northern Theater Command of Chinese PLA from January 2018 to October 2019 were equally divided into the control group and research group according to different surgical methods. The control group underwent laparotomy and the research group received endoluminal repair. The expression levels of serum T-cell subsets, plasma Notch1 and TACE proteins were compared before and 1 week after surgery between the two groups; the expression levels of plasma Notch1 and TACE proteins in patients with different tumor diameters in the research group were compared; the comparison of the surgical indexes and the incidence of complications was conducted. After treatment, the molecular level of CD3⁺ and CD4⁺ in the research group was significantly higher than that in the control group, whereas the molecular level of CD8⁺, and the expression levels of Notch1 and TACE proteins in the plasma were significantly lower than that in the control group (P < 0.05). In the research group, the expression levels of plasma Notch1 and TACE proteins were in direct proportion with tumor diameter (P < 0.05). The intraoperative blood loss in the research group was significantly less than that in the control group, the operation time, postoperative fasting time and postoperative hospital stay were significantly shorter than that in the control group, and the total incidence of complications (11.90%) was significantly lower than that in the control group (38.09%) (P < 0.05). At 12 months after operation, there was no statistically significant difference in the incidence of complications and mortality between the two groups. Endovascular therapy fro AAA can greatly improve the expression levels of T-lymphocyte subsets, Notch1 and TACE proteins, and markedly reduce the incidence of complications.

Epidemiology of endovascular and open repair for abdominal aortic aneurysms in the United States from 2004 to 2015 and implications for screening

BACKGROUND

Contemporary national trends in the repair of ruptured abdominal aortic aneurysms (AAAs) and intact AAAs are relatively unknown. Furthermore, screening is only covered by insurance for patients aged 65 to 75 years with a family history of AAAs and for men with a positive smoking history. It is unclear what proportion of patients who present with a ruptured AAA would have been candidates for screening.

METHODS

Using the National Inpatient Sample from 2004 to 2015, we identified ruptured and intact AAA admissions and repairs using the International Classification of Diseases codes. We generated the screening-eligible cohort using previously identified proportions of male smokers (87%) and all patients with a family history of AAAs (10%) and applied these proportions to patients aged 65 to 75 years. We accounted for those who could have had a previous AAA diagnosis (17%), either from screening or an incidental detection in patients aged >75 years who had presented with AAA rupture. The primary outcomes were treatment and in-hospital mortality between patients meeting the criteria for screening vs those who did not.

RESULTS

We evaluated 65,125 admissions for ruptured AAAs and 461,191 repairs for intact AAAs. Overall, an estimated 45,037 admitted patients (68%) and 25,777 patients who had undergone repair for ruptured AAAs (59%) did not meet the criteria for screening. Of the patients who did not qualify, 27,653 (63%) were aged >75 years, 10,603 (24%) were aged <65 years, and 16,103 (36%) were women. Endovascular AAA repair (EVAR) increased for ruptured AAAs from 10% in 2004 to 55% in 2015 (P < .001), with operative mortality of 35%. EVAR increased for intact AAAs from 45% in 2004 to 83% in 2015 (P < .001), with operative mortality of 2.0%.

CONCLUSIONS

Most patients who had undergone repair for ruptured AAAs did not qualify for screening. EVAR was the primary treatment of both ruptured and intact AAAs with relatively low in-hospital mortality. Therefore, expansion of the screening criteria to include selected women and a wider age range should be considered.

Frailty is a Poor Predictor of Postoperative Morbidity and Mortality After Ruptured Abdominal Aortic Aneurysm

BACKGROUND

Frailty has gained prominence as a predictor of postoperative outcomes across a number of surgical specialties, vascular surgery included. The role of frailty is less defined in the acute surgical setting. We assessed the prognostic value of frailty for patients undergoing surgery for a ruptured abdominal aortic aneurysm (rAAA).

METHODS

A single-institution retrospective chart review of all patients undergoing surgical intervention for rAAA between January 1, 2011 and November 27, 2019 was performed. Frailty was assessed for each patient using the modified frailty index (mFI), a validated frailty metric based on the Canadian Study of Health and Aging. Frailty was defined as an mFI ≥0.27. The performance of the mFI was compared to that of the Vascular Study Group of New England (VSGNE) rAAA mortality risk score. Chi square, Fisher's exact, and t tests, were used to evaluate for associations between frailty and in-hospital outcomes. Univariate and multivariate logistic regression were used to obtain odds ratios for in-hospital mortality. A receiver operating characteristic (ROC) curve was generated to compare the predictive value of the mFI and VSGNE score for in-hospital mortality.

RESULTS

Sixty patients were identified during the study period with an in-hospital mortality rate of 37%. Twenty-one patients were deemed frail by mFI metric and included all patients with known myocardial infarction, stroke with a neurologic deficit or dependent functional status, however the mortality rate did not differ significantly based on frailty status (33% nonfrail vs. 43% frail, P= 0.47). Frailty status was not significantly different for patients with acute kidney injury (10% nonfrail vs. 10% frail), prolonged intubation (13% vs. 5%), abdominal compartment syndrome (8% vs. 10%), and Type I or Type III endoleak (8% vs. 19%). On multivariate analysis controlling for systolic blood pressure <70 mm Hg, suprarenal aortic control, and creatinine >2.0 mg/dl, the mFI produced an adjusted odds ratio (aOR) of 0.7 (95% confidence interval [CI]: 0.2-3.0). The ROC curve for the mFI produced an area under the curve (AUC) of 0.55 (P= 0.55) for in-hospital mortality while that of the VSGNE score produced an AUC of 0.69 (P= 0.02).

CONCLUSIONS

The mFI did not significantly predict in-hospital outcomes after rAAA in this cohort. This suggests that the baseline health status of a patient with rAAA may play a less significant role in their postoperative prognosis than their acuity on presentation.

Survival and Living Situation After Ruptured Abdominal Aneurysm Repair in Octogenarians

OBJECTIVE

To determine the 30 day and one year mortality and post-operative living situation in octogenarians treated for ruptured abdominal aortic aneurysm (rAAA).

METHODS

A retrospective study was performed at four centres in the Netherlands. All consecutive patients aged ≥80 years, presenting with a rAAA between January 2013 and October 2018, were included. The primary outcomes were post-operative living situation and one year mortality.

RESULTS

In total, 157 patients were included. Forty-seven received palliative care and 110 patients had surgery. After endovascular or open repair, the one year mortality rate was 50.0%. The 30 day mortality rate was 40.8% (95% confidence interval [CI] 27-55) and 31.7% (95% CI 20-44), for endovascular and open repair, respectively (p = .32). Sixty-five per cent of survivors were discharged home, while 34.8% went to a nursing home for rehabilitation. Of the surviving patients, 82.6% went back to living in their pre-rupture home situation. Of the investigated variables, only a high body mass index proved a significant predictor of death at 30 days and one year. Compared with operated patients, patients turned down for surgery were older (mean age 87.5 ± 3.8 vs. 84.0 ± 3.5; p < .001), lived significantly more often in a nursing home (odds ratio 1.02, 95% CI 1.00-1.03; p < .001), were more often dependent (odds ratio 3.69, 95% CI 2.31-5.88; p < .001) and had a lower Glasgow Coma Scale score on arrival (odds ratio 0.42, 95% CI 0.25-0.69; p = .002). All palliative patients died within three days.

CONCLUSION

Overall treatment outcomes showed that octogenarians should not be denied surgery based on age alone, as half of the octogenarians that undergo surgical treatment are still alive one year after rAAA repair. In addition, > 80% returned to their own home after rehabilitation.

Evaluation of Survival Outcomes of Endovascular Versus Open Aortic Repair for Abdominal Aortic Aneurysms with a Big Data Approach

Abdominal aortic aneurysm (AAA) is a localized enlargement of the abdominal aorta. Once ruptured AAA (rAAA) happens, repairing procedures need to be applied immediately, for which there are two main options: open aortic repair (OAR) and endovascular aortic repair (EVAR). It is of great clinical significance to objectively compare the survival outcomes of OAR versus EVAR using randomized clinical trials; however, this has serious feasibility issues. In this study, with the Medicare data, we conduct an emulation analysis and explicitly "assemble" a clinical trial with rigorously defined inclusion/exclusion criteria. A total of 7826 patients are "recruited", with 3866 and 3960 in the OAR and EVAR arms, respectively. Mimicking but significantly advancing from the regression-based literature, we adopt a deep learning-based analysis strategy, which consists of a propensity score step, a weighted survival analysis step, and a bootstrap step. The key finding is that for both short- and long-term mortality, EVAR has survival advantages. This study delivers a new big data strategy for addressing critical clinical problems and provides valuable insights into treating rAAA using OAR and EVAR.

Open Surgical Repair of Abdominal Aortic Aneurysms Maintains a Pivotal Role in the Endovascular Era

Since the advent of endovascular aortic repair (EVAR) nearly three decades ago, there has been a paradigm shift in the treatment of the abdominal aortic aneurysm (AAA) to favor EVAR due to its reduced operative mortality, less invasive nature, and faster recovery times. However, more recently there has been an accumulation of data from large meta-analyses and randomized clinical trials revealing that EVAR has no survival benefit after approximately 2 years and is associated with substantially higher rates of reintervention and aneurysm rupture in the long term. These findings call into question the durability of EVAR compared with open aortic repair and emphasize the need for surgeons to remain competent with open aortic surgery in the modern era. This article will provide comprehensive review of a large body of literature comparing endovascular repair to open aortic surgery for the management of AAAs, and it will offer an overview of the open surgical repair technique for AAAs.

Endograft type and anesthesia mode are associated with mortality of endovascular aneurysm repair for ruptured abdominal aortic aneurysms

OBJECTIVE

Endovascular aneurysm repair has become the primary treatment modality for ruptured infrarenal abdominal aortic aneurysm. This study examines the impact of endograft type on perioperative outcomes for ruptured infrarenal abdominal aortic aneurysm.

METHOD

The targeted endovascular aneurysm repair files of the American College of Surgeons National Surgical Quality Improvement Program database (2012-2017) were used. Only patients treated for ruptured infrarenal abdominal aortic aneurysm were included. All patients requiring concomitant stenting of the visceral arteries or aneurysmal iliac arteries or open abdominal surgery were excluded. The characteristics of patients treated with the different endografts and the corresponding outcomes were compared using Stata software.

RESULTS

There were 479 patients treated with the three most common endografts: Cook Zenith (n = 127), Gore Excluder (n = 239), and Medtronic Endurant (n = 113). The number of other endografts was too small for statistical analysis. Compared to patients treated with Excluder or Endurant, the patients treated with Zenith had significantly lower body mass index (P < .001) and were less likely to be white (P < .001). On the other hand, patients treated with Endurant were less likely to be smoker (P = .016). Patients treated with Zenith had significantly larger ruptured infrarenal abdominal aortic aneurysm diameter (P = .045). The overall mortality was 18% and morbidity 74.3%. There was a statistically significant difference in overall mortality (Zenith = 11.8%, Excluder = 18%, Endurant = 24.8%, P = .033) but not morbidity (P = .808) between the three groups. Post hoc analysis for overall mortality showed only significant difference between Zenith and Endurant. The difference in mortality was not significant in patients presenting with ruptured infrarenal abdominal aortic aneurysm without hypotension (P = .065). On multivariable analysis, treatment with the Endurant endograft was associated with increased mortality compared to Zenith (odds ratio = 3.0 [confidence interval 1.31-6.7]). General anesthesia (odds ratio = 2.67 [confidence interval 1.02-7.02]), rupture with hypotension (odds ratio = 4.49 [confidence interval 2.54-7.95]), and dependent functional status (odds ratio = 5.7 [confidence interval 1.96-16.59]) were independently associated with increased mortality while increasing body mass index (odds ratio = 0.97 [confidence interval 0.95-0.99]) was associated with reduced risk of mortality.

CONCLUSIONS

This study highlights contemporary outcomes of endovascular aneurysm repair for ruptured infrarenal abdominal aortic aneurysm with relatively low mortality. Endograft type and anesthesia technique are modifiable factors that can potentially improve outcomes. Significant variation in the outcomes of the different endografts warrants further research.

Modern mortality risk stratification scores accurately and equally predict real-world postoperative mortality after ruptured abdominal aortic aneurysm

OBJECTIVE

It is often unclear which patients presenting with a ruptured abdominal aortic aneurysm (rAAA) are likely to survive after surgery. The Harborview Medical Center (HMC), Dutch Aneurysm Score (DAS), and Vascular Study Group of New England (VSGNE) risk scores have been recent attempts at predicting mortality in this setting. We compared the prognostic value of these scoring systems for patients at our institution with rAAA.

METHODS

A retrospective chart review was performed for all patients who received surgery at our institution for rAAA between January 1, 2011, and November 27, 2019. The χ², Fisher's exact, and t-tests were used to screen preoperative variables against in-hospital mortality. HMC, DAS, and VSGNE scores were calculated for each patient and tested against in-hospital mortality. Logistic regression and receiver operating characteristic curves were used to assess performance of each scoring system.

RESULTS

Sixty-four patients were identified during the study period. Fifteen patients were excluded because 4 patients chose comfort care and an additional 11 patients were missing key variables. The final cohort for analysis included 49 patients who underwent surgery, including 33 patients receiving endovascular repair and 16 patients receiving open repair. The in-hospital mortality was 37% (24% for endovascular repair vs 63% for open repair). Individual variables associated with in-hospital mortality were lowest preoperative systolic blood pressure (P = .036), creatinine greater than 2.0 mg/dL (P = .020), first recorded intraoperative pH (P = .007), and use of suprarenal aortic control (P = .025), and preoperative cardiac arrest approached significance (P = .051). Plots of the HMC and VSGNE scores vs in-hospital mortality rate produced linear relationships (R² = 0.97 and R² = 0.93, respectively), in which a higher score was associated with a greater likelihood of mortality. On logistic regression analysis using HMC score components, creatinine greater than 2.0 mg/dL produced a significant association with in-hospital mortality (odds ratio, 12.3; 95% confidence interval [CI], 1.1-131.7). Similar analysis using VSGNE components produced a significant association between suprarenal aortic control and in-hospital mortality (odds ratio, 5.5; 95% CI, 1.2-25.5). receiver operating characteristic curves produced an area under the curve of 0.74 (95% CI, 0.60-0.88), 0.73 (95% CI, 0.58-0.87), and 0.67 (95% CI, 0.51-0.83) for the HMC, VSGNE, and DAS, respectively.

CONCLUSIONS

The HMC, VSGNE, and DAS scores performed similarly and adequately predicted in-hospital mortality after rAAA. The HMC score holds the added benefit of using preoperative variables, setting it apart as a valid prognostic indicator in the preoperative setting.

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.

Patients with a Ruptured Abdominal Aortic Aneurysm Are Better Informed in Hospitals with an "EVAR-preferred" Strategy: An Instrumental Variable Analysis of the Dutch Surgical Aneurysm Audit

BACKGROUND

While several observational studies suggested a lower postoperative mortality after minimal invasive endovascular aneurysm repair (EVAR) in patients with a ruptured abdominal aortic aneurysm (RAAA) compared to conventional open surgical repair (OSR), landmark randomized controlled trials have not been able to prove the superiority of EVAR over OSR. Randomized controlled trials contain a selected, homogeneous population, influencing external validity. Observational studies are biased and adjustment of confounders can be incomplete. Instrumental variable (IV) analysis (pseudorandomization) may help to answer the question if patients with an RAAA have lower postoperative mortality when undergoing EVAR compared to OSR.

METHODS

This is an observational study including all patients with an RAAA, registered in the Dutch Surgical Aneurysm Audit between 2013 and 2017. The risk difference (RD) in postoperative mortality (30 days/in-hospital) between patients undergoing EVAR and OSR was estimated, in which adjustment for confounding was performed in 3 ways: linear model adjusted for observed confounders, propensity score model (multivariable logistic regression analysis), and IV analysis (two-stage least square regression), adjusting for observed and unobserved confounders, with the variation in percentage of EVAR per hospital as the IV instrument.

RESULTS

2419 patients with an RAAA (1489 OSR and 930 EVAR) were included. Unadjusted postoperative mortality was 34.9% after OSR and 22.6% after EVAR (RD 12.3%, 95% CI 8.5-16%). The RD adjusted for observed confounders using linear regression analysis and propensity score analysis was, respectively, 12.3% (95% CI 9.6-16.7%) and 13.2% (95%CI 9.3-17.1%) in favor of EVAR. Using IV analysis, adjusting for observed and unobserved confounders, RD was 8.9% (95% CI -1.1-18.9%) in favor of EVAR.

CONCLUSIONS

Adjusting for observed confounders, patients with an RAAA undergoing EVAR had a significant better survival than OSR in a consecutive large cohort. Adjustment for unobserved confounders resulted in a clinical relevant RD. An "EVAR preference strategy" in patients with an RAAA could result in lower postoperative mortality.

Contemporary mortality after emergent open repair of complex abdominal aortic aneurysms

OBJECTIVE

Mortality after open repair for emergent complex abdominal aortic aneurysm (AAA) is poorly defined. This study evaluated the 30-day mortality of open complex AAA repair performed for rupture or other emergent indication using a national surgical registry. We subsequently identified factors associated with mortality.

METHODS

The targeted vascular module from the American College of Surgeons National Surgical Quality Improvement Program was queried to identify patients undergoing open repair for juxtarenal and suprarenal AAAs or type IV thoracoabdominal aneurysms (TAAAs) for rupture or other emergent indication from 2011 to 2017. Univariate analyses were performed using the Fisher's exact test for categorical variables and the Wilcoxon rank sum test for continuous variables. Multivariable logistic regression was performed to identify factors independently associated with mortality.

RESULTS

We included 374 patients who underwent an emergent complex open AAA repair during the study period. There were 142 (38%) cases performed for rupture with hypotension, 141 (38%) for rupture without hypotension, 40 (11%) for symptomatic AAA, and 51 (14%) for another indication. The distribution by aneurysm type was 224 juxtarenal AAAs, 122 suprarenal AAAs, and 28 type IV TAAAs. Overall, there was a 30-day mortality of 32% (118 deaths). For those with juxtarenal AAA repair, 67 (30%) patients died within 30 days; there were 38 (31%) deaths within 30 days in those with suprarenal AAA, and 13 (46%) deaths within 30 days in those with type IV TAAA. On univariate analysis, preoperative variables associated with death were increasing age, use of a transperitoneal surgical approach, lower preoperative estimated glomerular filtration rate, low baseline albumin concentration (<3.5 g/dL), need for preoperative transfusion, low body mass index (<18.5 kg/m²), and hypotension at presentation. Intraoperative variables associated with mortality were supraceliac clamp location and concurrent renal revascularization. On multivariable analysis, factors independently associated with death included rupture with associated hypotension (reference: other emergent indication; adjusted odds ratio [AOR], 3.28; confidence interval [CI], 1.75-5.41; P < .001), age >60 years (reference: <60 years; AOR, 1.59; CI, 1.18-2.13; P = .002), longitudinal laparotomy incision (reference: retroperitoneal; AOR, 3.28; CI, 1.75-6.16; P < .001), and supraceliac cross-clamp (reference: clamp above one renal artery; AOR, 2.14; CI, 1.31-3.50; P = .003).

CONCLUSIONS

Nearly one-third of patients die within 30 days of emergent open complex AAA repair. Mortality is particularly high for patients with type IV TAAAs, approaching 50%. Predictors of 30-day mortality include rupture with associated hypotension, increasing age, supraceliac clamp location, and longitudinal transperitoneal repair approach. These results will help inform surgical decisions preoperatively and intraoperatively.

The Use of Iliac Branched Devices in the Acute Endovascular Repair of Ruptured Aortoiliac Aneurysms

BACKGROUND

The objective of this study was to evaluate the feasibility and midterm outcomes of iliac branch devices (IBDs) to preserve the internal iliac artery perfusion in emergent endovascular repair of ruptured aorto-iliac aneurysms.

METHODS

Between December 2012 and July 2017, a total of 8 IBDs were implanted in 6 patients (the median age 65 years; all men) in a single tertiary referral center. The indication for IBD implantation was a ruptured abdominal aortic aneurysm with a concomitant common iliac artery aneurysm (n = 4) or isolated CIA aneurysms (n = 2). The main outcome measures were technical and clinical success. The secondary outcomes were primary and primary assisted patency, the occurrence of type I/III endoleaks, and reinterventions.

RESULTS

All patients were hemodynamically stable during the procedures, which were performed under local anesthesia. Technical success was achieved in all cases (the median total procedure time of 188 min and the median IBD procedure time of 28 min). The median follow-up was 34 months (interquartile range 19-78). There were no deaths during the follow-up and no major complications unrelated to the IBD. Two (25%) secondary interventions were performed for IBD occlusion in patients with bilateral IBDs. The other reintervention was a type II endoleak embolization in 1 of these 2 patients. The freedom from reintervention estimate was 75% through 2 years. The overall primary assisted patency was 100% through 3 years.

CONCLUSIONS

The use of IBDs in the acute setting is feasible to exclude ruptured aortoiliac aneurysms while maintaining pelvic circulation. The secondary intervention rate is considerable; however, the midterm assisted primary patency rates are promising. Further studies are needed to guide patient selection and to evaluate longer term outcomes.

Disparities in mortality after abdominal aortic aneurysm repair are linked to insurance status

OBJECTIVE

The objective of this study was to determine differences in mortality after abdominal aortic aneurysm (AAA) repair based on insurance type.

METHODS

In this retrospective cohort study, data from all-payer patients in nonpsychiatric hospitals in New York, Maryland, Florida, Kentucky, and California from January 2007 to December 2014 (excluding California, ending December 2011) were extracted from the State Inpatient Databases, Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality. There were 90,102 patients ≥18 years old with available insurance data who underwent open AAA repair or endovascular aneurysm repair (EVAR) identified using International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes 3844, 3925, and 3971. EVAR patients were identified using the procedure code 3971, and the remainder of cases were categorized as open. Patients were divided into cohorts by insurance type as Medicare, Medicaid, uninsured (self-pay/no charge), other, or private insurance. Patients were further stratified for subgroup analyses by procedure type. Unadjusted rates of in-hospital mortality, the primary outcome, as well as secondary outcomes, such as surgical urgency, 30-day and 90-day readmissions, length of stay, total charges, and postoperative complications, were examined by insurance type. Adjusted odds ratios (ORs) for in-hospital mortality were calculated using multivariate logistic regression models fitted to the data. The multivariate models included patient-, surgical-, and hospital-specific factors with bivariate baseline testing suggestive of association with insurance status in addition to variables that were selected a priori.

RESULTS

Medicaid and uninsured patients had the highest rates of mortality relative to private insurance beneficiaries in all cohorts. Medicaid patients incurred a 47% increase in the odds of mortality, the highest among the insured, after all AAA repairs (OR, 1.47; 95% confidence interval [CI], 1.23-1.76), whereas uninsured patients experienced a 102% increase in the odds of mortality (OR, 2.02; 95% CI, 1.54-2.67). Subgroup analyses for open AAA repair and EVAR corroborated that Medicaid insurance (open repair OR, 1.37 [95% CI, 1.14-1.64]; EVAR OR, 2.06 [95% CI, 1.40-3.04]) and uninsured status (open repair OR, 1.85 [95% CI, 1.35-2.54]; EVAR OR, 2.96 [95% CI, 1.82-4.81]) were associated with the highest odds of mortality after both procedures separately.

CONCLUSIONS

This study demonstrates that Medicaid insurance and uninsured status are associated with higher unadjusted rates and adjusted ORs for in-hospital mortality after AAA repair relative to private insurance status. Primary payer status therefore serves as an independent predictor of the risk of death subsequent to AAA surgical interventions.

Association of Operative Repair Type and Trauma Center Designation With Outcomes in Ruptured Abdominal Aortic Aneurysm Repair

OBJECTIVE

Open repair of ruptured abdominal aortic aneurysm (rAAA) has shown improved outcomes at trauma centers. Whether the benefit of trauma center designation extends to endovascular repair of rAAA is unknown.

METHODS

Retrospective cohort study using the California Office of Statewide Health Planning and Development 2007 to 2014 discharge database to identify patients with rAAA. Data included demographic and admission factors, discharge disposition, International Classification of Diseases, Ninth Revision, Clinical Modification codes, and hospital characteristics. Hospitals were categorized by trauma center designation and teaching hospital status. The effect of repair type and trauma center designation (level I, level II, or other-other trauma centers and nondesignated hospitals) was evaluated to determine rates and risks of 9 postoperative complications, in-hospital mortality, and 30-day postdischarge mortality.

RESULTS

Of 1941 rAAA repair patients, 61.2% had open and 37.8% had endovascular; 1.0% had both. Endovascular repair increased over the study interval. Hospitals were 12.0% level I, 25.0% level II, and 63.0% other. A total of 48.7% of hospitals were teaching hospitals (level I, 100%; level II, 42.2%; and other, 41.8%). Endovascular repair was significantly more common at teaching hospitals (41.5% vs 34.3%, P < .001) and was the primary repair method at level I trauma centers (P < .001). Compared with open repair, endovascular repair was protective for most complications and in-hospital mortality. The risk for in-hospital mortality was highest among endovascular patients at level II trauma centers (hazard ratio 1.67, 95% confidence interval [CI]: 0.95-2.92) and other hospitals (hazard ratio 1.66, 95% CI: 1.01-2.72).

CONCLUSIONS

Endovascular repair overall was associated with a lower risk of adverse outcomes. Endovascular repair at level I trauma centers had a lower risk of in-hospital mortality which may be a result of their teaching hospital status, organizational structure, and other factors. The weight of the contributions of such factors warrants further study.

Sex differences in Japanese patients with ruptured aortic aneurysms

OBJECTIVE

This study aimed to assess the sex differences in clinical presentation and outcomes of Japanese patients with ruptured aortic aneurysm (rAA) using a large nationwide claims-based database in Japan.

METHODS

We identified patients hospitalized in certified teaching hospitals in Japan with rAA between April 1, 2012, and March 31, 2015. Patients' characteristics and in-hospital outcomes were compared between men and women. The Barthel index was used for evaluating functional status at discharge by examining the ability to perform basic daily activities.

RESULTS

Of 7086 eligible patients, 32.3% (2291/7086) were women. Women were older than men (81.9 years vs 76.1 years; P < .001), had higher prevalence of coma at admission (33.2% vs 25.2%; P < .001), and were less likely to undergo emergency operation including endovascular aneurysm repair (35.7% vs 51.1%; P < .001). The unadjusted mortality rate (62.5% vs 52.0%; P < .001) and Barthel index at discharge (78.7 vs 86.1; P < .001) were significantly worse in women than in men. However, multilevel mixed-effect logistic regression analyses showed that female sex itself was not an independent predictor for in-hospital death (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.78-1.04; P = .17). Older age, coma at admission, and vasopressor use were detected as independent predictors for in-hospital death. The same results were confirmed for each rupture site. Stratified analyses showed that older women (threshold, 80 years; OR, 0.81; 95% CI, 0.66-0.98; P = .028) and those who underwent emergency operation (OR, 0.75; 95% CI, 0.61-0.93; P = .009) showed significantly better outcomes than men.

CONCLUSIONS

In a univariate analysis, female patients with rAA showed worse mortality than men because of their older age, more severe clinical presentation, and low emergency operation rate. However, after adjustment for covariates, female sex itself was not associated with increased mortality.

Morphologic and Operative Evolution of Open Ruptured Abdominal Aortic Aneurysm Repair

BACKGROUND

Increased use of endovascular repair for intact abdominal aortic aneurysms has fundamentally shifted the approach to ruptured aneurysms. Unfortunately, not all patients are anatomically suited for endovascular repair. It is hypothesized that, in the endovascular era, patients undergoing open repair are increasingly complex; with an unknown impact on postoperative morbidity and mortality.

MATERIAL AND METHODS

The Cleveland Clinic Foundation database was queried for all patients undergoing open repair of ruptured abdominal aortic aneurysms (rAAA) from 2006 to 2015. Electronic medical charts and cross-sectional imaging were retrospectively reviewed. The overall patient cohort was dichotomized between early (E-OR, 2006 to 2010) and late open repairs (L-OR, 2011 to 2015). Groups were compared based on demographic, anatomic, and perioperative variables. The primary endpoint was perioperative mortality. Secondary endpoints included overall mortality, late aneurysm-related mortality, and perioperative morbidity.

RESULTS

Of 140 patients who underwent open repair of rAAA (63, E-OR; 77, L-OR), 76% had cross-sectional imaging available for review. Aneurysm repairs in the later time period had significantly shorter infrarenal neck lengths, were more likely to have a prior aortic intervention, tended to have poor access vessels, and were more likely to require visceral or renal revascularization (each P < 0.05). While late survival did not differ between time periods, perioperative mortality (27 vs. 46%, P = 0.021) and late aneurysm-related mortality (29.9% vs. 47.6%, P = 0.031) was lower for L-OR compared with E-OR. While no anatomic variables significantly impacted survival, early time period of repair, presence of chronic kidney disease, and need for cardiopulmonary resuscitation were predictive of both perioperative and overall mortality on univariate and multivariate analysis.

CONCLUSIONS

Despite the increasing anatomic and operative complexity of patients undergoing open repair of rAAAs, perioperative mortality and late aneurysm-related mortality have improved over time. These results highlight the need for both systems and expertise needed to appropriately treat this changing patient population.

Comparison of perioperative costs with fast-track vs standard endovascular aneurysm repair

Background

Perioperative health care utilization and costs in patients undergoing elective fast-track vs standard endovascular aneurysm repair (EVAR) remain unclear.

Methods

The fast-track EVAR group included patients treated with a 14 Fr stent graft, bilateral percutaneous access, no general anesthesia or intensive care monitoring, and next-day hospital discharge. The standard EVAR group was identified from Medicare administrative claims using a matching algorithm to adjust for imbalances in patient characteristics. Hospital outcomes included operating room time, intensive care monitoring, hospital stay, secondary interventions, and major adverse events (MAEs). Perioperative outcomes occurring from hospital discharge to 30 days postdischarge included MAE, secondary interventions, and unrelated readmissions.

Results

Among 1000 matched patients (250 fast-track; 750 standard), hospital outcomes favored the fast-track EVAR group, including shorter operating room time (2.30 vs 2.83 hrs, P<0.001), shorter hospital stay (1.16 vs 1.69 d, P<0.001), less need for intensive care monitoring (4.4% vs 48.0%, P<0.001), and lower secondary intervention rate (0% vs 2.4%, P=0.01). Postdischarge outcomes also favored fast-track EVAR with a lower rate of MAE (0% vs 7.2%, P<0.001) and all-cause readmission (1.6% vs 6.8%, P=0.001). The total cost to the health care system during the perioperative period was $26,730 with fast-track EVAR vs $30,730 with standard EVAR. Total perioperative health care costs were $4000 (95% CI: $3130–$4830) lower with fast-track EVAR vs standard EVAR, with $2980 in savings to hospitals and $1030 savings to health care payers.

Conclusion

A fast-track EVAR protocol using a 14 Fr stent graft resulted in shorter procedure time, lower intensive care utilization, faster discharge, lower incidence of MAE, lower readmission rates, and lower perioperative costs compared to standard EVAR.

Sex differences in repair rates and outcomes of patients with ruptured abdominal aortic aneurysm

BACKGROUND

Data are conflicting on sex differences in ruptured abdominal aortic aneurysm (rAAA) repair rates and outcomes have rarely been addressed. The aim of this study was to investigate differences in the management and outcome of rAAA in men and women, and to describe time trends over a 15-year interval.

METHODS

Data on patients with rAAA were extracted from the Swedish National Patient Registry and the Cause of Death Registry for the interval 2001-2015. The study included patients with rAAA whether or not they were admitted to any hospital in Sweden. A propensity score-matched model was used to determine sex differences in repair type and outcome after rupture. Time trends for rAAA events and mortality were investigated.

RESULTS

Some 10 724 patients were identified. A higher percentage of men were admitted to hospital (79·8 versus 77·5 per cent; P = 0·011). Of those admitted, a higher percentage of men than women were treated (56·6 versus 40·4 per cent, P < 0·001). Women were less likely to be treated when diagnosed with rAAA (average treatment effect (ATE) in the model -0·080, 95 per cent c.i. -0·106 to -0·055; P < 0·001). Thirty-day mortality was also higher in women (ATE 0·094, 0·053 to 0·135; P < 0·001); this effect persisted to 1 year (ATE 0·095, 0·052 to 0·137; P < 0·001). Time trends indicated a decrease in rAAA incidence, mostly owing to a decrease among men.

CONCLUSION

In this study, fewer women with rAAA received surgery and 30-day mortality was higher than in men. There was an overall decrease in rAAA incidence, principally in men.

Strategy of endovascular versus open repair for patients with clinical diagnosis of ruptured abdominal aortic aneurysm: the IMPROVE RCT

BACKGROUND

Ruptured abdominal aortic aneurysm (AAA) is a common vascular emergency. The mortality from emergency endovascular repair may be much lower than the 40-50% reported for open surgery.

OBJECTIVE

To assess whether or not a strategy of endovascular repair compared with open repair reduces 30-day and mid-term mortality (including costs and cost-effectiveness) among patients with a suspected ruptured AAA.

DESIGN

Randomised controlled trial, with computer-generated telephone randomisation of participants in a 1 : 1 ratio, using variable block size, stratified by centre and without blinding.

SETTING

Vascular centres in the UK (n = 29) and Canada (n = 1) between 2009 and 2013.

PARTICIPANTS

A total of 613 eligible participants (480 men) with a ruptured aneurysm, clinically diagnosed at the trial centre.

INTERVENTIONS

A total of 316 participants were randomised to the endovascular strategy group (immediate computerised tomography followed by endovascular repair if anatomically suitable or, if not suitable, open repair) and 297 were randomised to the open repair group (computerised tomography optional).

MAIN OUTCOME MEASURES

The primary outcome measure was 30-day mortality, with 30-day reinterventions, costs and disposal as early secondary outcome measures. Later outcome measures included 1- and 3-year mortality, reinterventions, quality of life (QoL) and cost-effectiveness.

RESULTS

The 30-day mortality was 35.4% in the endovascular strategy group and 37.4% in the open repair group [odds ratio (OR) 0.92, 95% confidence interval (CI) 0.66 to 1.28; p = 0.62, and, after adjustment for age, sex and Hardman index, OR 0.94, 95% CI 0.67 to 1.33]. The endovascular strategy appeared to be more effective in women than in men (interaction test p = 0.02). More discharges in the endovascular strategy group (94%) than in the open repair group (77%) were directly to home (p < 0.001). Average 30-day costs were similar between groups, with the mean difference in costs being -£1186 (95% CI -£2997 to £625), favouring the endovascular strategy group. After 1 year, survival and reintervention rates were similar in the two groups, QoL (at both 3 and 12 months) was higher in the endovascular strategy group and the mean cost difference was -£2329 (95% CI -£5489 to £922). At 3 years, mortality was 48% and 56% in the endovascular strategy group and open repair group, respectively (OR 0.73, 95% CI 0.53 to 1.00; p = 0.053), with a stronger benefit for the endovascular strategy in the subgroup of 502 participants in whom repair was started for a proven rupture (OR 0.62, 95% CI 0.43 to 0.89; p = 0.009), whereas aneurysm-related reintervention rates were non-significantly higher in this group. At 3 years, considering all participants, there was a mean difference of 0.174 quality-adjusted life-years (QALYs) (95% CI 0.002 to 0.353 QALYs) and, among the endovascular strategy group, a cost difference of -£2605 (95% CI -£5966 to £702), leading to 88% of estimates in the cost-effectiveness plane being in the quadrant showing the endovascular strategy to be 'dominant'.

LIMITATIONS

Because of the pragmatic design of this trial, 33 participants in the endovascular strategy group and 26 in the open repair group breached randomisation allocation.

CONCLUSIONS

The endovascular strategy was not associated with a significant reduction in either 30-day mortality or cost but was associated with faster participant recovery. By 3 years, the endovascular strategy showed a survival and QALY gain and was highly likely to be cost-effective. Future research could include improving resuscitation for older persons with circulatory collapse, the impact of local anaesthesia and emergency consent procedures.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN48334791 and NCT00746122.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 31. See the NIHR Journals Library website for further project information.

Instrumental variable based estimation under the semiparametric accelerated failure time model

Randomized controlled trials are the gold standard for estimating causal effects of treatments or interventions, but in many cases are too costly, too difficult, or even unethical to conduct. Hence, many pressing medical questions can only be investigated using observational studies. However, direct statistical modeling of observational data can result in biased estimates of treatment effects due to unmeasured confounding. In certain cases, instrumental variable based techniques can be used to remove such biases. These techniques are indeed widely studied and used in econometrics under parametric outcome models, however limited works have focused on the utilization of instrumental variables in survival analysis, where semiparametric models are often necessary. The additional challenge in analyzing survival data is the presence of censoring. In this paper, we introduce an instrumental variable method that relaxes the strong assumptions of previous works and provides consistent estimation of the causal effect of a treatment on a survival outcome. We demonstrate the efficacy of our method in various simulated settings and an analysis of Medicare enrollment data comparing two prevalent surgical procedures for abdominal aortic aneurysm from an observational study.

What Did Endovascular Aortic Repair Bring for the Treatment Strategy of Abdominal Aortic Aneurysm?

Objective: We examined the effects of the introduction of endovascular aortic repair (EVAR) on treatment for abdominal aortic aneurysms (AAAs).

Subjects: We compared patients in the following three periods: period I (January 2002–December 2006, 105 patients), period II (January 2007–December 2011, 242 patients, duration of 5 years after the introduction of EVAR), and period III (January 2012–December 2016, 237 patients, duration of 5 years after period II). We used the American Society of Anesthesiologists (ASA) classification for risk assessment.

Results: In the Open repair (OR) group, the incidences of ASA class 2 increased and classes 3 and 4 decreased significantly in periods II and III compared with period I. In all periods, there were no in-hospital deaths. Suprarenal aortic cross-clamping was required in 18 patients (19.1%) in period III and 5 patients (6.3) in period I, and the difference was significant (P<0.05). In the EVAR group, no differences in age, sex, or ASA classification class were observed between periods II and III. In period II, one patient died due to aneurysm rupture during surgery. Significant differences were observed when comparing both groups in periods II and III: patients in the EVAR group were older (P<0.01) and the OR group had a higher proportion of ASA class 2 patients and the EVAR group had a higher proportion of ASA class 3 or 4 patients (P<0.01). Among all AAA surgeries, rupture occurred in 25 patients (23.8%) in period I, 18 patients (7.4) in period II, and 16 patients (6.8) in period III. The number of ruptures was significantly lower in periods II and III than in period I (P<0.01).

Conclusions: The findings of this study suggest that EVAR should be indicated for high-risk patients and had the good outcome of AAA treatment. (This is a translation of Jpn J Vasc Surg 2018; 27: 27–32.)

Systematic review and meta-analysis of the risk of bowel ischemia after ruptured abdominal aortic aneurysm repair

OBJECTIVE

Outcomes after repair of ruptured abdominal aortic aneurysm (RAAA) have improved in the last decade. It is unknown whether this has resulted in a reduction of postoperative bowel ischemia (BI). The primary objective was to determine BI prevalence after RAAA repair. Secondary objectives were to determine its major sequelae and differences between open repair (OR) and endovascular aneurysm repair (EVAR).

METHODS

This systematic review (PROSPERO CRD42017055920) followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. MEDLINE and Embase were searched for studies published from 2005 until 2018. The methodologic quality of observational studies was assessed with the Methodological Index for Non-Randomized Studies (MINORS) tool. The quality of the randomized controlled trials (RCTs) was assessed with the Cochrane Collaboration's tool for assessing risk of bias. BI prevalence and rates of BI as cause of death, reoperation, and bowel resection were estimated with meta-analyses with a random-effects model. Differences between OR and EVAR were estimated with pooled risk ratios with 95% confidence intervals (CIs). Changes over time were assessed with Spearman rank test (ρ). Publication bias was assessed with a funnel plot analysis.

RESULTS

A total of 101 studies with 52,670 patients were included; 72 studies were retrospective cohort studies, 14 studies were prospective cohort studies, 12 studies were retrospective administrative database studies, and 3 studies were RCTs. The overall methodologic quality of the RCTs was high, but that of observational studies was low. The pooled prevalence of BI ranged from of 0.08 (95% CI, 0.07-0.09) in database studies to 0.10 (95% CI, 0.08-0.12) in cohort studies. The risk of BI was higher after OR than after EVAR (risk ratio, 1.79; 95% CI, 1.25-2.57). The pooled rate of BI as cause of death was 0.04 (95% CI, 0.03-0.05), and that of BI as cause of reoperation and bowel resection ranged between 0.05 and 0.07. BI prevalence did not change over time (ρ, -0.01; P = .93). The funnel plot analysis was highly suggestive of publication bias.

CONCLUSIONS

The prevalence of clinically relevant BI after RAAA repair is approximately 10%. Approximately 5% of patients undergoing RAAA repair suffer from severe consequences of BI. BI is less prevalent after EVAR than after OR.