Mid-term cost-effectiveness analysis of open and endovascular repair for ruptured abdominal aortic aneurysm

A Comparison of Endovascular Aneurysm Repair and Open Repair for Ruptured Aortic Abdominal Aneurysms

Management modalities of ruptured abdominal aortic aneurysm (AAA) include ruptured open aneurysm repair (rOAR) and ruptured endovascular aneurysm repair (rEVAR). In this study, we aim to systematically review all the previously published randomized controlled trials (RCTs) that compared rOAR and rEVAR. A systematic search was performed in the following databases: PubMed, Scopus, Web of Science, Google Scholar, Clinical trials, and others with all the potentially relevant keywords that were adjusted to meet the search strategy for each database to collect all the relevant studies that were published up to January 2021. A total of 11 studies were identified through our comprehensive search. Among these studies, seven represented the IMPROVE trial, two represented the AJAX trial, and two represented the Nottingham and ECAR trials, each, while the remaining four studies were not RCTs; however, these were included in the discussion as they obtained data from the IMPROVE trial. The IMPROVE trials preferred EVAR use due to the potential survival benefit and improved quality of life, although the EVAR and OAR had similar mortality rates. In the AJAX and ECAR, the mortality rates favored EVAR over OAR with no significance while the opposite was noticed in the Nottingham trial with no significance also. Similar rates of re-interventions and complications were also noticed and some studies reported that EVAR is cost-effective. Overall evidence slightly favors EVAR over OAR and further studies are needed.

ANALYSIS OF SPIN IN VASCULAR SURGERY RANDOMIZED CONTROLLED TRIALS WITH NONSIGNIFICANT OUTCOMES

OBJECTIVES

Spin is the manipulation of language that distorts the interpretation of objective findings. The purpose of this study is to describe the characteristics of spin found in statistically nonsignificant randomized controlled trials (RCT) comparing carotid endarterectomy (CEA) to carotid artery stenting (CAS) for carotid stenosis (CS), and endovascular repair (EVAR) to open repair (OR) for abdominal aortic aneurysms (AAA).

METHODS

A search of MEDLINE, EMBASE, and the Cochrane Controlled Register of Trials was performed in June 2020 for studies published describing AAA or CS. All phase three RCTs with nonsignificant primary outcomes comparing OR to EVAR or CEA to CAS were included. Studies were appraised for the characteristics and severity of spin using a validated tool. Binary logistic regression was performed to assess the association of spin grade to (1) funding source (commercial vs non-commercial) and (2) the publishing journal's impact factor.

RESULTS

Thirty-one of 355 articles captured were included for analysis. Spin was identified in nine abstracts (9/18) and 13 main texts (13/18) of AAA articles and seven abstracts (7/13) and ten main texts (10/13) of CS articles. For both AAA and CS articles, spin was most commonly found in the manuscript discussion section, with the most commonly employed strategy being the interpretation of statistically nonsignificant primary results to show treatment equivalence or rule out adverse treatment effects. Increasing journal impact factor was associated with a statistically significant lower likelihood of spin in the study title or abstract conclusion (βOR = 0.96, 95% CI: 0.94 - 0.98, p < 0.01) while no significant association could be found with funding source (βOR = 1.33, 95% CI: 0.30-5.92, p = 0.71).

CONCLUSIONS

A large proportion of statistically nonsignificant RCTs contain interpretations that are inconsistent with their results. These findings should prompt authors and readers to appraise study findings independently and to limit the use of spin in study interpretations.

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.

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.

Extended use of endovascular aneurysm sealing for ruptured abdominal aortic aneurysms

Endovascular repair of abdominal aortic aneurysms (EVAR) is now an established treatment modality for suitable patients presenting with aneurysm rupture. EVAR for ruptured aneurysms reduces transfusion, mechanical ventilation, intensive care. and hospital stay when compared with open surgery. In the emergency setting, however, EVAR is limited by low applicability due to adverse clinical or anatomical characteristics and increased need for reintervention. In addition, ongoing bleeding from aortic side branches post-EVAR can cause hemodynamic instability, larger hematomas, and abdominal compartment syndrome. Endovascular aneurysm sealing, based on polymer filling of the aneurysm, has the potential to overcome some of the limitations of EVAR for ruptured aneurysms and to improve outcomes. Recent literature suggests that endovascular aneurysm sealing can be performed with early mortality similar to that of EVAR for ruptured aortic aneurysms, but experience is limited to a few centers and a small number of patients. The addition of chimney grafts can increase the applicability of endovascular aneurysm sealing in order to treat short-neck and juxtarenal aneurysms as an alternative to fenestrated endografts. Further evaluation of the technique, with larger longitudinal studies, is necessary before advocating wider implementation of endovascular aneurysm sealing in the emergency setting.

Endovascular Repair for Ruptured Abdominal Aortic Aneurysms has Improved Outcomes Compared to Open Surgical Repair

INTRODUCTION

Ruptured abdominal aortic aneurysm (rAAA) remains a critical diagnosis, and research is needed to address outcomes following surgical repair. The purpose of this study was to compare nationwide outcomes for patients who received either endovascular repair (EVAR) or open surgical repair (OSAR) for rAAA.

METHODS

The Medicare Provider Analysis and Review file from 2005 to 2009 was used to identify patients diagnosed with rAAA and treated with either EVAR or OSAR. Those patients with both procedures were excluded. Primary outcomes included mortality, postoperative complications, and readmission rates. Secondary outcomes included hospital resource utilization and length of stay (LOS).

RESULTS

A total of 8480 patients with rAAA who underwent EVAR (n = 1939) or OSAR (n = 6541) were identified. On multivariate regression, the likelihood of dying in the hospital after OSAR compared to EVAR was significantly greater (odds ratio [OR] = 1.95; 95% confidence interval [CI] = 1.74-2.18). There was significantly greater frequency of postoperative complications after OSAR compared to EVAR (OR = 2.1, 95%CI = 1.86-2.37, P < .0001). Freedom from readmission after OSAR was significantly greater than that after EVAR. Total hospital cost for all services after EVAR was greater than that after OSAR (US$100 875 vs US$89 035; P < .0001), but intensive care unit (ICU) cost for EVAR was significantly less than that for OSAR (US$5516 vs US$8600; P < .0001). Total hospital and ICU LOS were shorter in EVAR compared to OSAR (P < .0001 for both).

DISCUSSION

EVAR for rAAA has shown mortality benefits over OSAR as well as reduced ICU and total LOS. This data suggest EVAR is associated with a greater survival benefit, fewer postoperative complications, and may help improve hospital resource utilization.

Incidence and Outcomes of Severe Renal Impairment Following Ruptured Abdominal Aortic Aneurysm Repair

INTRODUCTION

Acute kidney injury (AKI) following ruptured abdominal aortic aneurysm (rAAA) repair is common and multifactorial. A standard definition of AKI after endovascular repair (EVAR), the Aneurysm Renal Injury Score (ARISe), has been proposed to facilitate standardised reporting and thus improve understanding of this issue.

METHODS

Data were collected retrospectively on AKI in a prospectively maintained database of all patients treated for rAAA in a single tertiary referral centre since the availability of routine out of hours emergency EVAR. The ARISe score was used to describe the degree of AKI and factors which correlated with poor renal outcomes were assessed.

RESULTS

Two-hundred and five patients were treated between January 2006 and April 2014. Of these, 125 were treated with open repair (OSR) and 80 were treated with EVAR. Severe AKI (defined as ARISe score ≥3) occurred in 36% of patients. After correction for confounders, patients treated with OSR were significantly more likely to develop severe AKI (43% vs. 26%, p = .02). There was no significant difference in preoperative serum creatinine between groups, but increased preoperative serum creatinine was strongly associated with severe AKI postoperatively (p < .001). Age, sex, endograft type, and preoperative CT scanning were not associated with differences in renal outcomes. Clamp position above renal arteries was predictive of severe AKI in patients treated with OSR (p < .01). Patients suffering severe AKI had significantly higher mortality at 30 days and 12 months (28% vs. 5% and 44% vs. 13%, p < .001 for both comparisons).

CONCLUSION

Severe AKI is common following successful repair of rAAA. In this large case series of high-risk patients, OSR was associated with significantly higher rates of severe AKI compared with EVAR, despite the increased dose of contrast involved in EVAR and the older age of these patients. In turn, severe AKI was associated with higher mortality rates.

Midterm Re-interventions and Survival After Endovascular Versus Open Repair for Ruptured Abdominal Aortic Aneurysm

OBJECTIVE

To compare the midterm re-intervention and survival rates after EVAR and OR for ruptured abdominal aortic aneurysms (RAAA).

METHODS

Observational cohort study including all consecutive RAAA patients between 2004 and 2011 in 10 hospitals in the Amsterdam ambulance region. The primary end point was re-interventions within 5 years of the primary intervention. The secondary end point was death. The outcomes were estimated by survival analyses, compared using the logrank test, and subsequently adjusted for possible confounders using Cox proportional hazard models. Re-interventions were estimated in all patients and in patients who survived their hospital stay.

RESULTS

Of 467 patients with a RAAA, 73 were treated by EVAR and 394 by OR. Five years after the primary intervention, the rates of freedom from re-intervention were 55% for EVAR (26/73, 95% CI: 41-69%) and 60% for OR (130/394, 95% CI: 55-66%) (p = .96). After adjustment for age, sex, comorbidity, and pre-operative hemodynamic stability, the risk of re-intervention was similar (HR 1.01, 95% CI: 0.65-1.55). The survival rates were 36% for EVAR (45/73, 95% CI: 24-47%) and 38% for OR (235/394, 95% CI: 33-43%) (p = .83). In 297 patients who survived their hospital stay, the rates of freedom from re-intervention were 66% for EVAR (15/54, 95% CI: 52-81%) and 90% for OR (20/243, 95% CI: 86-95%) (p < .01). After adjustment for age and sex, the risk of re-intervention was higher after EVAR (HR 0.27, 95% CI: 0.14-0.52).

CONCLUSIONS

Five years after the primary intervention, endovascular and open repair for ruptured abdominal aortic aneurysm resulted in similar re-intervention and survival rates. However, in patients who survived their hospital stay the re-intervention rate was higher for EVAR than for OR.