Editor's Choice - Endovascular vs. Open Repair for Abdominal Aortic Aneurysm: Systematic Review and Meta-analysis of Updated Peri-operative and Long Term Data of Randomised Controlled Trials

Outcomes of off-the-shelf multibranched stent grafts with intentional occlusion of directional branches using endovascular plugs during endovascular repair of complex aortic aneurysms

OBJECTIVE

To evaluate the technique and outcomes of intentional occlusion of directional branches (DBs) using endovascular plugs during branched endovascular aortic repair using off-the-shelf Zenith t-Branch thoracoabdominal (TAAA) stent grafts.

METHODS

We reviewed the clinical data and outcomes of all consecutive patients treated by branched endovascular aortic repair using off-the-shelf Zenith t-Branch TAAA stent-graft (Cook Medical, Bloomington, Ind) in seven academic centers from 2013 to 2019. All patients had at least one DB intentionally occluded using extension of the branch with balloon or self-expandable covered stent, followed by placement of endovascular plugs. Intentional occlusion was indicated in patients with variations in the normal four-vessel renal-mesenteric anatomy, pre-existing dialysis, or in those who failed catheterization of a target vessel. End points were 30-day/in-hospital mortality, major adverse events, secondary interventions, target artery (TA) patency, TA instability, and patient survival.

RESULTS

There were 100 patients, 65 male and 35 female, with median age of 71 years (interquartile range [IQR], 66-75 years). Of these, 31 patients (31%) had urgent/emergent operations for symptomatic/contained ruptured aneurysms. The median aneurysm diameter was 72 mm (IQR, 61-85 mm). A total of 290 renal-mesenteric arteries were incorporated with a median of three (IQR, 3-3) vessels/patient. Indications for DB occlusion were less than four suitable renal-mesenteric targets in 84 patients or pre-existing dialysis and inability to catheterize a target vessel in eight patients each. There were 110 DBs occluded by vascular plugs, including 48 celiac axis, one superior mesenteric artery, and 61 renal DBs. Thirty-day/in-hospital mortality was 10%, including 9% for elective and 13% for urgent/emergent procedures. Major adverse events occurred in 44 patients (44%), including acute kidney injury in 19 patients (19%), estimated blood loss >1 L in 12 patients (12%), respiratory failure and new onset dialysis in six patients (6%) each, bowel ischemia in five patients (5%), and myocardial infarction and paraplegia in two patients (2%) each. The median follow-up was 5 months (range, 1-13 months). Eighteen patients (18%) required secondary interventions, none for problems related to the occluded DB. There were no endoleaks related to the occluded DB. At 2 years, primary and secondary patency and freedom from TA instability were 93% ± 3%, 97% ± 2%, and 91% ± 4%, respectively. Freedom from secondary interventions and patient survival were 75% ± 6% and 63% ± 7%, respectively.

CONCLUSIONS

Intentional occlusion of DBs using endovascular plugs allows versatile use of a four-vessel off-the-shelf multi-branched TAAA stent graft in patients with variations in the normal renal and mesenteric anatomy or when technical difficulties prevent successful target vessel stenting. There were no endoleaks or secondary interventions associated with the occluded DB.

Persisting Type 2 Endoleaks Following EVAR for AAA Are Associated With AAA Expansion

PURPOSE

To determine the evolution of abdominal aortic aneurysm (AAA) diameter in the presence of persisting type 2 endoleaks (pEL2) following endovascular abdominal aortic aneurysm repair (EVAR).

MATERIALS AND METHODS

This is a retrospective, single-center, case-control study. All patients with pEL2 (pEL2 group, persisting for > 12 months) between 2004 and 2018 were identified and compared with a 1:1 age- and gender-matched control with no endoleak (control group). Primary outcome measures were freedom from AAA expansion and freedom from AAA shrinkage over time. AAA diameter measurements were performed on computed tomography angiography (CTA). Secondary outcome measures were survival, AAA-related mortality, reinterventions for pEL2, incidence of secondary type 1 endoleaks (EL1), and infrarenal aortic branch vessel anatomy.

RESULTS

A total of 773 patients were treated with EVAR for AAA between 2004 and 2018. Of them, 286 patients demonstrated type 2 endoleaks (EL2) in postoperative CTA or intraoperative angiography (37%). Forty-five of 286 EL2 (15.7%) were pEL2 (pEL2 group). Freedom from AAA expansion in the pEL2 group was 100%, 96.7%, 85.2%, and 54.3% after 1, 2, 3, and 4 years, respectively, compared with 100% after 1, 2, 3, and 4 years in the control group (p<0.01). Freedom from AAA shrinkage in the pEL2 group after 1, 2, 3, and 4 years was 95.5%, 90.4%, 90.4%, and 79.1%, respectively, compared with 86.7%, 34.8%, 19.3%, and 19.3% in the control group (p<0.01). Overall survival at 1, 2, 3, and 4 years was 100%, 97.6%, 95.0% and 95.0% in the pEL2 group and 100% at 1, 2, 3, and 4 years in the control group (p=0.17). There were no AAA-related deaths in either group. Patients with pEL2 had a significantly increased number of infrarenal aortic branches (p<0.05, respectively). Eighteen patients (40.0%) in the pEL2 group underwent 34 reinterventions for pEL2, with a median follow-up (FU) of 925 days (0-4173). Clinical success was achieved in 9 patients (50.0%). Four patients (8.9%) with pEL2 developed secondary EL1 after a median FU of 1278 days (662-2121).

CONCLUSION

pEL2 are associated with AAA expansion during midterm FU. Further studies are warranted to evaluate the association of AAA expansion due to pEL2 with clinical outcomes to allow recommendations with regard to treatment indications.

A Finite Element Based Analysis of a Hemodynamics Efficient Flow Stent Suitable for Different Abdominal Aneurysm Shapes

This research aimed to examine the impact of a proposed flow stent (PFS) on different abdominal artery shapes. For that purpose, a finite element-based model using the computational fluid dynamics (CFD) method is developed. The effect of PFS intervention on the hemodynamic efficiency is estimated by all of the significant criteria used for the evaluation of aneurysm occlusion and possible rupture; the flow velocity, pressure, wall shear stress (WSS), and WSS-related indices. Results showed that PFS intervention preserves the effects of high flow rate and decreases irregular flow recirculation in the sac of the aneurysm. The flow velocity decreases inside the aneurysm sac in the range of 55% to 80%. The time-averaged wall shear stress (TAWSS) was reduced from 42% to 53% by FPS deployment. The simulation results implies that PFS could heal an aneurysm efficiently with a mechanism that causes the development of thrombus and ultimately leads to aneurysm resorption.

Endovascular Abdominal Aortic Aneurysm Repair with Ovation Alto stent graft: Protocol of the ALTAIR study (ALTo endogrAft Italian Registry). (Preprint)

Background

Since 2010, the Ovation Abdominal Stent Graft System has offered an innovative sealing option for abdominal aortic aneurysm (AAA) by including a sealing ring filled with polymer 13 mm from the renal arteries. In August 2020, the redesigned Ovation Alto, with a sealing ring 6 mm closer to the top of the fabric, received CE Mark approval.

Objective

This registry study aims to evaluate intraoperative, perioperative, and postoperative results in patients treated by the Alto stent graft (Endologix Inc.) for elective AAA repair in a multicentric consecutive experience.

Methods

All consecutive eligible patients submitted to endovascular aneurysm repair (EVAR) by Alto Endovascular AAA implantation will be included in this analysis. Patients will be submitted to EVAR procedures based on their own preferences, anatomical features, and operators experience. An estimated number of 300 patients submitted to EVAR with Alto stent graft should be enrolled. It is estimated that the inclusion period will be 24 months. The follow-up period is set to be 5 years. Full data sets and cross-sectional images of contrast-enhanced computed tomography scan performed before EVAR, at the first postoperative month, at 24 or 36 months, and at 5-year follow-up interval will be reported in the central database for a centralized core laboratory review of morphological changes. The primary endpoint of the study is to evaluate the technical and clinical success of EVAR with the Alto stent graft in short- (90-day), mid- (1-year), and long-term (5-year) follow-up periods. The following secondary endpoints will be also addressed: operative time; intraoperative radiation exposure; contrast medium usage; AAA sac shrinkage at 12-month and 5-year follow-up; any potential role of patients’ baseline characteristics, valuated on preoperative computed tomography angiographic study, and of device configuration (number of component) in the primary endpoint.

Results

The study is currently in the recruitment phase and the final patient is expected to be treated by the end of 2023 and then followed up for 5 years. A total of 300 patients will be recruited. Analyses will focus on primary and secondary endpoints. Updated results will be shared at 1- and 3-5-year follow-ups.

Conclusions

The results from this registry study could validate the safety and effectiveness of the new design of the Ovation Alto Stent Graft. The technical modifications to the endograft could allow for accommodation of a more comprehensive range of anatomies on-label.

Trial Registration

ClinicalTrials.gov NCT05234892; https://clinicaltrials.gov/ct2/show/NCT05234892

International Registered Report Identifier (IRRID)

PRR1-10.2196/36995

Abdominal aortic aneurysm clinical practice guidelines: a methodological assessment using the AGREE II instrument

OBJECTIVES

Abdominal aortic aneurysm (AAA) clinical practice guidelines (CPGs) provide evidence-based information on patient management; however, methodological differences exist in the development of CPGs. This study examines the methodological quality of AAA CPGs using a validated assessment tool.

METHODS

Medline, EMBASE and online CPG databases were searched from 1946 to 31 October 2021. Full-text, English language, evidence-based AAA CPGs were included. Consensus-based CPGs, summaries of CPGs or CPGs which were only available on purchase were excluded. Five reviewers assessed their quality using the Appraisal of Guidelines for Research and Evaluation II instrument. An overall guideline assessment scaled score of ≥80% was considered as the threshold to recommend CPG use in clinical practice.

RESULTS

Seven CPGs were identified. Scores showed good inter-reviewer reliability (intraclass correlation coefficient 0.943, 95% CI 0.915 to 0.964). On average, CPGs performed adequately with mean scaled scores of over 50% in all domains. However, between CPGs, significant methodological heterogeneity was observed in all domains. Four CPGs scored ≥80% (European Society of Cardiology, the Society of Vascular Surgery, the European Society of Vascular Surgery and the National Institute of Health and Care Excellence), supporting their use in clinical practice.

CONCLUSIONS

Four CPGs were considered of adequate methodological quality to recommend their use in clinical practice; nonetheless, these still showed areas for improvement, potentially through performing economic analysis and trial application of recommendations. A structured approach employing validated CPG creation tools should be used to improve rigour of AAA CPGs. Future work should also evaluate recommendation accuracy using validated appraisal tools.

Proximal Seal Dilatation following Fenestrated Endovascular Repair for Complex Abdominal Aortic Aneurysms

OBJECTIVES

Although Proximal neck dilatation following infrarenal endovascular aneurysm repair (EVAR) is common and is associated with proximal graft failure, little is known about sealing zone dilatation and its clinical relevance following fenestrated EVAR (FEVAR). We studied proximal seal dilatation (PSD) dynamics following FEVAR and assessed its clinical significance.

METHODS

We included all consecutive patients treated for a juxta-/supra-renal aneurysm with fenestrated EVAR using the Zenith Fenestrated Endovascular Graft (Cook Medical, Bloomington, Ind) from 2008 to 2018 in two large teaching hospitals in the Netherlands. The primary outcome was PSD over time and was determined using a linear mixed-effects model. Secondary outcomes included associations for early PSD and difference in aortic dilatation at the level of the covered-stent compared to the bare-stent. Proximal seal related adverse events were also obtained.

RESULTS

Our cohort included 84 patients with a median CTA follow-up time of 24.5 months [IQR 17-42]. Maximum aneurysm-diameter was 60.1 mm (IQR 56.9-67.2). Mean proximal seal diameter at baseline was 26.2 mm (±2.8), mean stent oversizing was 20.1% (±9.1), and mean proximal seal length was 29.5 mm (±11.7). Proximal seal dilatation of 1.7 mm (95%CI:1.4-2.1) was found in the first year, decelerating thereafter (2^nd-year: 0.9mm/year [95%CI:0.7-1.1]). Over 10% PSD at one year occurred in 22 patients (27%) and was associated with stent-graft oversizing (OR: 1.1 [95%CI:1.03-1.2], p=.008) and a lower number of target vessels (four fenestrations/ref two fenestrations: OR: 0.13 [95%CI:0.02-0.74], p=.029). At last available imaging, dilatation difference was higher at the level of the covered stent compared with the bare stent (3.0mm [IQR 1.3-5.1] vs. 1.6mm [IQR 0.8-2.5], p<.001). During the study period, only one patient (1.2%) developed a proximal seal related-adverse event (type-IA endoleak).

CONCLUSION

PSD is present following FEVAR, occurring at a faster rate in the first year and subsequently decelerating thereafter, similarly to neck dilatation after standard infrarenal EVAR. Although its clinical implication seems to remain limited in the first years following implantation, further research is required to assess the effect of PSD on long-term FEVAR outcomes.

Quality-adjusted life year comparison at medium term follow-up of endovascular versus open surgical repair for abdominal aortic aneurysm in young patients

Objectives

This study aimed to compare the quality of life and cost effectiveness between endovascular aneurysm repair (EVAR) and open surgical repair (OSR) in young patients with abdominal aortic aneurysm (AAA).

Design

This was a single-center, observational, and retrospective study.

Materials and methods

A retrospective analysis was conducted of patients with AAA, who were <70 years old and underwent EVAR or OSR between January 2012 and October 2016. Only patients with aortic morphology that was suitable for EVAR were enrolled. Data on the complication rates, medical expenses, and expected quality-adjusted life years (QALYs) were collected, and the cost per QALY at three years was compared.

Results

Among 90 patients with aortic morphology who were eligible for EVAR, 37 and 53 patients underwent EVAR and OSR, respectively. No significant differences were observed in perioperative cardiovascular events and death between the two groups. However, during the follow-up period, patients undergoing OSR showed a significantly lower complication rate (hazard ratio [HR] = 0.11; P = .021). From the three-year cost-effectiveness analysis, the total sum of costs was significantly lower in the OSR group (P < .001) than that in the EVAR group, and the number of QALYs was superior in the OSR group (P = .013). The cost per QALY at three years was significantly lower in the OSR group than that in the EVAR group (mean: $4038 vs. $10 137; respectively; P < .001)

Conclusions

OSR had lower complication rates and better cost-effectiveness than EVAR Among young patients with feasible aortic anatomy.

Controversies in Vascular Surgery

There have been significant advances in vascular surgery in recent years. These advances include procedural techniques, choice of procedure, and application of nonoperative management. Endovascular techniques have expanded greatly over the past decade. As a result, for many clinical scenarios there is more than 1 option for management, which has given rise to controversies in the choice of best management. This article reviews current controversies in the management of carotid artery disease, abdominal aortic aneurysms, acute deep venous thrombosis, and inferior vena cava filter placement.

Comparison of Early and Mid-Term Outcomes After Fenestrated-Branched Endovascular Aortic Repair in Patients With or Without Prior Infrarenal Repair

OBJECTIVE

The purpose of this study was to compare short- and mid-term outcomes of fenestrated-branched endovascular repair (F-BEVAR) of pararenal (PRAA)/thoracoabdominal (TAAA) aortic aneurysms in patients with or without prior endovascular/open (EVAR/OAR) infrarenal aortic repair.

METHODS

Data from consecutive F-BEVAR (2010-2019) at two high-volume aortic centers were retrospectively reviewed. Primary endpoints were technical success, 30-day mortality, and overall survival. Secondary endpoints included 30-day major adverse events (MAE), freedom from type I/III endoleaks, reinterventions, sac expansion, and target vessel (TV) primary patency.

RESULTS

A total of 222 consecutive patients were included for analysis; of these 58 (26.1%) had prior infrarenal repair (EVAR=33, OAR=25) and 164 (73.9%) had native PRAA/TAAA. At baseline, patients with prior infrarenal repair were older (mean age=75.1 vs 71.6 years, p=.005) and the proportion of females was lower (8.6% vs 29.3%, p=.002). Technical success was 97.8% (n=217) in the entire cohort, without any significant differences between study groups (94.8% vs 98.8%, p=.08). At 30 days, there were no significant differences between patients with prior infrarenal repair as compared with those without in rate of MAE (44.8% vs 54.9%, p=.59). The 5-year estimate of survival for those who underwent native aortic repair was 61.6%, versus 61.3% for those who had a previous repair (p=.67). The 5-year freedom from endoleaks I/III estimates were significantly lower in patients who had prior infrarenal repair as compared with patients undergoing treatment of native aneurysms (57.1% vs 66.1%, p=.03), mainly owing to TV-related endoleaks (ie, type IC and/or IIIC endoleaks). No significant differences were found between study groups in rates of reinterventions and TV primary patency. Five-year estimates of freedom from sac increase >5mm were significantly lower in patients who received F-BEVAR after previous infrarenal repair as compared with those who underwent treatment of native aneurysms (48.6% vs 77.5%, p=.002).

CONCLUSIONS

F-BEVAR is equally safe and feasible for treatment of patients with prior infrarenal repair as compared with those undergoing treatment for native aneurysms. Increased rates of TV-related endoleaks were observed which could lead to lower freedom from aneurysm sac shrinkage during follow-up. Nevertheless, the 5-year rates of reinterventions and TV patency were similar, thereby indicating that overall effectiveness of treatment remained satisfactory at mid-term.

Impact of proximal neck anatomy on short-term and mid-term outcomes after treatment of abdominal aortic aneurysms with new-generation low-profile endografts. Results from the multicentric "ITAlian north-east registry of ENDOvascular aortic repair with the BOltOn Treo endograft (ITA-ENDOBOOT)"

INTRODUCTION

The aim of the study was to evaluate the short-term and mid-term technical and clinical outcomes of the Bolton Treo endograft in subjects with abdominal aortic aneurysm (AAA) requiring endovascular aortic repair (EVAR) and assess if presence of hostile proximal neck would represent a risk factor for increased failure rates.

METHODS

A retrospective review of all consecutive patients who had undergone elective or non-elective EVAR with the Bolton Treo endograft at five institutions located in the North-East of Italy (January 2016-December 2020) was performed. The main exposure variable for this study was presence of hostile (HAN) or friendly (FAN) aortic neck.

RESULTS

A total of 137 consecutive patients were treated with the Bolton Treo endograft at participating institutions; of these 63 (46%) presented HAN while 74 (54%) had FAN. At baseline, no significant differences were observed in the distribution of demographics and comorbidities between study groups. Two type Ia endoleaks (EL) were detected at completion angiography, all in patients with HAN but none in patients with FAN (3% vs 0%, p=.04), but no type III EL were identified in the whole cohort. The median duration of follow-up in the study cohort was 30 months (IQR 22-34 months) and was similar between study groups (p=.87). At three-years, survival estimates were 89% and 91% (p=.82) in patients with HAN and FAN, respectively. At three years, patients with HAN had significantly lower freedom from type IA endoleak as compared with patients with FAN (87% vs 94%, p=.02). No significant differences were found between study groups in the three-year estimates of freedom from reinterventions (80% vs 86%, p=.28). Using cox proportional hazards, presence of type II EL (HR 3.15, 95%CI 1.18-8.5, p=.02) and presence of type IA EL (HR 4.22, 95%CI 1.39-12.85, p=.01) were found as independent predictors for reinterventions in univariate analysis, although they were no longer significant in the multivariate model. Freedom from sac increase >5mm at three years were not significantly different between study groups (92% vs 91%, p=.95).

CONCLUSIONS

Within a contemporary multicentric real-world experience, EVAR with the Bolton Treo endograft shows a satisfactory safety profile in the immediate postoperative phase and acceptable outcomes during mid-term follow-up. Presence of HAN is correlated with development of type Ia EL (either early following stent-graft implantation or late after EVAR) which, in turn, may represent a significant factor leading to reinterventions.

Long-term results of low-profile stent grafts for treatment of infrarenal aortic aneurysms: Results from a retrospective multicenter registry

OBJECTIVE

In recent years, manufacturers have developed new stent grafts with lower profiles to increase the endovascular aneurysm repair applicability. As reported by the current European Society for Vascular Surgery guidelines, long-term evaluation of such low-profile platforms is strongly recommended. This study aims to report outcomes beyond 5 years from a multicenter registry, including a real-world cohort of patients electively treated with low-profile stent grafts.

METHODS

A retrospective data collection of patients who had undergone elective implantation of low-profile endograft ≤16 Fr. (Zenith LP, Ovation, Incraft) was performed in nine centers. The primary endpoint was a long-term primary clinical success. Secondary endpoints were survival rate, freedom from abdominal aortic aneurysm (AAA)-related death, freedom from type I to III endoleak, limb patency, and freedom from all reinterventions. The Kaplan-Meier curves were stratified for investigative devices. A multivariate analysis evaluated predictors of primary clinical success and reintervention rate.

RESULTS

A total of 619 patients were enrolled (Ovation, n = 373; Incraft, n = 111; and Zenith LP, n = 135), with a mean follow-up of 56.8 ± 22.8 months. The overall primary and the secondary clinical success rate at 8 years was 72.1% and 93.8%, respectively. At 8 years, overall survival was 53.2%, freedom from AAA-related death was 94.4%, freedom from reintervention was 74%, freedom from type I/III endoleak was 86.9%, and limb patency was 90.4%. A significantly worse primary clinical success of the Zenith LP was recorded as dependent on more limb-related events. No differences between platforms were registered in the rate of AAA-related deaths, open conversion, sac enlargement, and type I/III endoleaks (P = .26). Multivariate analysis identified iliac tortuosity (hazard ratio, 2.053) and Zenith LP (hazard ratio, 3.818) as significant independent predictors of clinical failure and reintervention.

CONCLUSION

Low-profile stent grafts have acceptable long-term outcomes. Overall survival and AAA-related death were in line with those reported for traditional devices. Long-term surveillance and reintervention, when necessary, remain crucial to guarantee durability.

Endograft apposition and infrarenal neck enlargement after endovascular aortic aneurysm repair

BACKGROUND

Sufficient apposition and oversizing of the endograft in the aortic neck are both essential for durable endovascular aneurysm repair (EVAR). These measures are however not regularly stated on post-EVAR computed tomography angiography (CTA) scan reports. In this study endograft apposition and neck enlargement (NE) after EVAR with an Endurant II(s) endograft were analyzed and associated with supra- and infrarenal aortic neck morphology.

METHODS

In 97 consecutive elective patients, the aortic neck morphology was measured on the pre-EVAR CTA scan on a 3mensio vascular workstation. The distance between the lowest renal artery and the proximal edge of the fabric (shortest fabric distance, SFD), and the shortest length of circumferential apposition between endograft and aortic wall (shortest apposition length, SAL) was determined on the early post-EVAR CTA scan. NE, defined as the aortic diameter change between pre- and post-EVAR CTA scan, was determined at eight levels: +40, +30, +20, +15, +10, 0, -5 and -10 mm relative to the lowest renal artery baseline. The aortic neck diameter and preoperative oversizing were correlated to NE with the Pearson correlation coefficient. The effective post-EVAR endograft oversizing is calculated from the nominal endograft diameter and the post-EVAR neck diameter where the endograft is circumferentially apposed.

RESULTS

The median time (interquartile range, IQR) between the EVAR procedure and the pre- and post-EVAR CTA scan was 40 (25, 71) days and 36 (30, 46) days, respectively. The Endurant II(s) endograft was deployed with a median (IQR) SFD of 1.0 (0.0, 3.0) mm. The SAL was <10 mm in 9% of patients and significantly influenced by the pre-EVAR aortic neck length (p=0.001), hostile neck shape (p=0.017), and maximum curvature at the suprarenal aorta (p=0.039). The median (interquartile range) SAL was 21.0 (15.0, 27.0) mm with a median (IQR) pre-EVAR infrarenal neck length of 23.5 (13.0, 34.8) mm. The median (IQR) difference between the SAL and neck length was -5.0 (-12.0, 2.8) mm. Significant (p<.001) NE of 1.7 (0.9, 2.5) mm was observed 5 mm below the renal artery baseline, which resulted in an effective post-EVAR endograft oversizing <10% in 43% of the patients. No correlation was found between NE and aortic neck diameter or preoperative oversizing.

CONCLUSIONS

Circumferential apposition between an endograft and the infrarenal aortic neck, SAL, and NE can be derived from standard postoperative CT scans. These variables provide essential information about the post-procedural endograft and aortic neck morphology regardless of the preoperative measurements. Patients with SAL <10 mm or effective oversizing <10% due to NE may benefit from intensified follow-up, but clinical consequences of SAL and NE should be evaluated in future longitudinal studies with longer term follow-up.

ePTFE-based biomedical devices: An overview of surgical efficiency

Polytetrafluoroethylene (PTFE) is a ubiquitous material used for implants and medical devices in general because of its high biocompatibility and inertness: blood vessel, heart, table jawbone, nose, eyes, or abdominal wall can benefit from its properties in case of disease or injury. Its expanded version, ePTFE is an improved version of PTFE with better mechanical properties, which extends its medical applications. A material as frequently used as ePTFE with these exceptional properties deserves a review of its main uses, developments, and possibility of improvements. In this systematic review, we examined clinical trials related to ePTFE-based medical devices from the literature. Then, we excluded all trials using ePTFE as a control to test other devices. ePTFE-coated stents, hemodialysis and bypass grafts, guided bone and tissue regeneration membranes, hernia and heart repair and other devices are reviewed. The rates of success using these devices and their efficiency compared to other materials used for the same purposes are reported. ePTFE appears to be more or just as efficient compared to them. Some success rates remain low, suggesting the need of improvement ePTFE for medical applications.

Recurrent infection is more common after endovascular versus open repair of infected abdominal aortic aneurysm: Systematic review and meta-analysis

OBJECTIVE

Controversy has continued regarding the use of endovascular aneurysm repair (EVAR) vs open aneurysm repair (OAR) for infected abdominal aortic aneurysms (AAAs). In the present study, we investigated the comparative outcomes of EVAR and OAR for the treatment of infected AAAs.

METHODS

We conducted a systematic review and meta-analysis using the MEDLINE and EMBASE databases through May 2021. We included studies that had described both EVAR and OAR for the treatment of infected AAAs. The primary endpoints were the rates of recurrent infection and related rupture and/or death. Perioperative and 1-year mortality and readmissions and reinterventions were also analyzed.

RESULTS

Fourteen observational studies describing a total of 1203 patients (EVAR, 359 [29.8%]; OAR, 844 [70.2%]) were eligible for qualitative analysis. The baseline characteristics included diabetes mellitus (33.2%), fever at presentation (71.6%), rupture at diagnosis (26.1%), and positive blood cultures (52.5%). The mean follow-up period ranged from 12 to 40 months. The use of EVAR became more prevalent in recent years (2016-2020, 32.4%) compared with the former period (2010-2015, 13.8%; P < .0001). Fenestrated, branched, or concomitant visceral debranching EVAR was performed in 6.1% of cases. In OAR, surgical debridement was consistently performed, and in situ reconstruction was applied in 82.2% and an omental flap in 51.5%. In nine studies considered for quantitative analysis, the patients' background (EVAR, n = 264; OAR, n = 274) were statistically balanced. The crude rates of recurrent infection and related rupture or death were 13.6% (95% confidence interval [CI], 8.8%-18.5%) and 4.9% (95% CI 1.8%-8.0%), respectively. The pooled analyses depicted significantly higher rates of recurrent infection after EVAR than after OAR (relative risk [RR], 2.42; 95% CI, 1.80-3.27; P < .0001; I² = 0%). Recurrent infection-related rupture or death (RR, 1.51; 95% CI, 0.70-3.23; P = .29; I² = 0%), perioperative death (RR, 0.80; 95% CI, 0.39-1.65; P = .55; I² = 35%), 1-year mortality (hazard ratio, 1.12; 95% CI, 0.97-1.28; P =.13; I² = 0%), and readmission or reintervention (RR, 1.16; 95% CI, 0.74-1.82; P =.52; I² = 0%) were not significantly different statistically between the two groups. Funnel plots showed no evidence of publication bias. Sensitivity analyses of leave-one-out meta-analysis confirmed higher rates of recurrent infection after EVAR.

CONCLUSIONS

EVAR has become more prevalent as the initial treatment of infected AAAs. Although operative and 1-year survival were similar between OAR and EVAR groups, recurrent infection was more frequent after EVAR. This limitation should be weighed in selecting patients for EVAR in infected AAAs. Postoperative graft and infection surveillance are critical, especially after EVAR.

[Case load and quality indicators in the treatment of abdominal aortic aneurysms]

BACKGROUND

The MTL30 (mortality, transfer, length of stay) was proposed as a surrogate parameter for evaluating the quality of large and potentially complication-prone visceral surgical interventions.

OBJECTIVE

The aim of this study was to find out to what extent the MTL30 can be correlated with the results of the abdominal aortic aneurysm (AAA) registry of the German Institute for Vascular Health Research (DIGG) of the German Society for Vascular Surgery and Vascular Medicine (DGG) and with the case volume of the participating hospitals.

MATERIAL AND METHODS

Elective endovascular abdominal aortic aneurysm repair (EVAR) was performed in 14,282 patients and open repair (OAR) in 3923 patients. Case volume of the treating hospitals, hospital mortality, length of stay and transfer to another acute care hospital were determined 30 days after the index intervention.

RESULTS

The hospital mortality was 1.3% for EVAR and 4.9% for OAR (p = 0.000), the MTL30 was 5.0% and 14.4%, respectively (p = 0.000). For EVAR, no relationship between case volume and hospital mortality (quintile 1: 1.0%; quintile 5: 1.3%) as well as case volume and MTL30 (quintile 1: 5.3%; quintile 5: 5.3%) could be demonstrated. Also in OAR there was no significant relationship between case volume and hospital mortality (quintile 1: 5.8%, quintile 5: 3.5%; p = 0.505) and case volume and MTL30 (quintile 1: 16.4%, quintile 5: 12.2%, p = 0.110). With a hospital mortality rate of 7.2% (5-10%) the MTL30 for OAR was 17.6%. In both EVAR and OAR, the length of stay correlated significantly with hospital mortality and MTL30.

DISCUSSION

A clear relationship between hospital case volume and hospital mortality could not be shown in the AAA registry of the DIGG. The same was true for the MTL30. It remains to be seen whether the MTL30 offers an additional benefit compared to the recording of hospital mortality and inpatient length of stay as a quality parameter.

Thirty-day Results from the ZEPHYR Registry: Outcomes of EVAR Using the Zenith Alpha™ Abdominal Endovascular Graft for the Treatment of AAA in 347 Patients

BACKGROUND

To report technical and clinical 30-day results following treatment with the Zenith Alpha™ abdominal stent graft from the ZEnith alPHa for aneurYsm Repair Registry (ZEPHYR).

METHODS

Multicenter, nonrandomized, single arm, core laboratory-controlled, prospective registry collecting data on the Zenith Alpha Abdominal Endovascular Graft being used in subjects with abdominal aortic aneurysms (AAA) from sites in Germany, Belgium, and The Netherlands between December 2016 and December 2019. Inclusion criteria were non-ruptured AAAs with a maximum diameter ≥50 mm or enlargement >5 mm over 6 months with an AAA neck length ≥10 mm (site reported). Primary outcome measure was treatment success at 30 days. Treatment success was defined as a combined endpoint consisting of technical and clinical success. Technical success was defined as successful stent graft delivery and deployment as well as successful removal of the delivery system. Clinical success at 30 days was defined as freedom from type I and III endoleak, aneurysm rupture, conversion to open surgery and stent graft occlusion.

RESULTS

Three hundred forty-seven subjects were included from 14 sites with a median age of 73.0 years (IQR 68.0-79.0). Thirty-four patients were female (9.8%). The median AAA diameter was 58.3 mm (IQR 55.0-63.5). The median proximal neck diameter was 23.6 mm (IQR 22.0-25.2) with a median proximal neck length of 24.4 mm (IQR 15.0-34.8) and a median infrarenal neck angulation of 24.5° (IQR 15.0-35.0). The right and left common iliac diameter were 16.1 mm (IQR 14.1-19.4) and 16.2 mm (IQR 14.1-19.1), respectively. The treatment success rate at 30 days was 94.8% (N = 329). Technical success was achieved in 333 patients (96.0%). The clinical success rate at 30 days was 98.8% (N = 343). Three patients had limb occlusions at 30 day follow up (0.9%). One patient had a type Ib endoleak (0.3%). Seventy percent of vascular access approaches were percutaneous. The reintervention rate was 1.7% (N = 6) within 30 days. Indications for reinterventions were a false aneurysm at puncture site (N = 1), limb complications (N = 2), stentgraft-associated renal artery occlusions (N = 2), and an external iliac artery thrombosis (N = 1).

CONCLUSIONS

Endovascular aneurysm repair using the Zenith Alpha Abdominal Endovascular Graft is effective in the short term. Long term results will be reported in the future.

Prognostic Role of Severe Infrarenal Aortic Neck Angulation in Endovascular Aneurysm Repair

OBJECTIVE

To investigate whether patients with severe infrarenal aortic neck angulation have worse outcomes than those without severe angulation after endovascular aneurysm repair (EVAR).

DATA SOURCES

The HDAS (Healthcare Database Advanced Search) interface developed by NICE (National Institute for Health and Care Excellence) was used to search electronic bibliographic databases.

REVIEW METHODS

Studies comparing outcomes of standard EVAR in patients with and without severe neck angulation were considered. Pooled outcome estimates were calculated using the odds ratio (OR) or hazard ratio (HR) and 95% confidence interval (CI), using the Mantel-Haenszel or inverse variance method, as appropriate. Random effects models of meta-analysis were applied. The GRADE (Grading of Recommendation, Assessment, Development, and Evaluation) methodology was used to assess the certainty of evidence.

RESULTS

Ten studies reporting a total of 7 371 patients (1 576 with severe neck angulation and 5 795 without) were included. The studies reported medium term follow up. No statistically significant difference was found for the primary outcomes (overall mortality: HR 1.27, 95% CI 0.88 - 1.85, low certainty; aneurysm related mortality: HR 1.07, 95% CI 0.80 - 1.44, moderate certainty; aneurysm rupture: HR 1.41, 95% CI 0.66 - 2.99, low certainty). The hazard of type Ia endoleak (HR 1.86, 95% CI 1.32 - 2.61) and re-intervention was higher in patient with severe angulation (HR 1.24, 95% CI 1.01 - 1.54), but there was no significant difference in the odds of adjunctive procedures (OR 1.23, 95% CI 0.48 - 3.11), or the hazard of sac expansion (HR 0.83, 95% CI 0.44 - 1.55) or stent migration (HR 1.22, 95% CI 0.78 - 1.92). Meta-analysis of studies that conducted multiple Cox regression analysis showed no significant difference for any of the primary outcomes.

CONCLUSION

Severe neck angulation may not be a poor prognostic indicator for overall/aneurysm related mortality and rupture in the medium term after EVAR but may increase the risk of late type 1 endoleaks and re-intervention; therefore, patients require close surveillance.

Mechanisms of abdominal aortic aneurysm progression: A review

Abdominal aortic aneurysm (AAA) is a common disease associated with significant cardiovascular morbidity and mortality. Up to now, there is still controversy on the choice of treatment method of AAA. Even so, the mechanisms of AAA progression are poorly defined, making targeting new therapies problematic. Current evidence favors an interaction of the hemodynamic microenvironment with local and systemic immune responses. In this review, we aim to provide an update of mechanisms in AAA progression, involving hemodynamics, perivascular adipose tissue, adventitial fibroblasts, vasa vasorum remodeling, intraluminal thrombus, and distribution of macrophage subtypes.

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

OBJECTIVE

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

SUMMARY BACKGROUND DATA

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Early and mid-term outcomes following open surgical conversion after failed endovascular aneurysm repair from the "Italian North-easT RegIstry of surgical Conversion AfTer Evar" (INTRICATE)

OBJECTIVE

To report the early and mid-term outcomes following open surgical conversion (OSC) after failed endovascular aortic repair (EVAR) using data from a multicentric registry.

METHODS

A retrospective study was carried out on consecutive patients undergoing OSC after failed EVAR at eight tertiary vascular units from the same geographic area in the North-East of Italy, from April 2005 to November 2019. Study endpoints included early and follow-up outcomes.

RESULTS

144 consecutive patients were included in the study. Endoleaks were the most common indication for OSC (50.7%), with endograft infection (24.6%) and occlusion (21.9%) being the second most prevalent causes. The overall rate of 30-day all-cause mortality was 13.9% (n=20); 32 patients (22.2%) experienced at least one major complication. Mean length of stay (LoS) was 13 ± 12.7 days. On multivariate logistic regression, age (OR 1.09, 95% CI 1.01-1-19, p= .02), renal clamping time (OR 1.07, 95% CI 1.02-1.13, p= .01), and suprarenal/celiac clamping (OR 6.66, 95% CI 1.81-27.1, p= .005) were identified as independent predictors of peri-operative major complications. Age was the only factor associated with peri-operative mortality at 30 days. Renal clamping time > 25 minutes had sensitivity of 65% and specificity of 70% in predicting the occurring of major adverse events (AUC 0.72; 95% CI 0.61-0.82). At 5 years, estimated survival was significantly lower for patients treated due to aortic rupture/dissection (28%, 95% CI 13-61), compared to patients in whom the indication for treatment was endoleak (54%, 95% CI 40-73), infection (53%, 95% CI 30-94), or thrombosis (82%, 95% CI 62-100; p= .0019). 5-year survival rates were significantly lower in patients who received emergent treatment (28%, 95% CI 14-55) as compared with those who were treated in urgent (67%, 95% CI 48-93) or elective setting (57%, 95% CI 43-76; p= .00026). Subjects who received suprarenal/celiac (54%, 95% CI 36-82) or suprarenal (46%, 95% CI 34-62) aortic cross-clamping had lower survival rates at 5 years than those whose aortic-cross clamp site was infrarenal (76%, 95% CI 59-97; p= .041). Using multivariate Cox Proportional Hazard, older age and emergency setting were independently associate with higher risk for overall 5 years mortality.

CONCLUSIONS

OSC after failed EVAR was associated with relatively high rates of early morbidity and mortality, particularly for emergency setting surgery. Endoleaks with secondary sac expansion were the main indication for OSC and suprarenal aortic cross-clamping was frequently required. Endograft infection and emergent treatment remained associated with poorer short-term and long-term survival.

Retroperitoneal versus transperitoneal approach for elective open abdominal aortic aneurysm repair

BACKGROUND

There has been extensive debate in the surgical literature regarding the optimum surgical access approach to the infrarenal abdominal aorta during an operation to repair an abdominal aortic aneurysm. The published trials comparing retroperitoneal (RP) and transperitoneal (TP) aortic surgery show conflicting results. This is an update of the review first published in 2016.

OBJECTIVES

To assess the effectiveness and safety of the retroperitoneal versus transperitoneal approach for elective open abdominal aortic aneurysm repair on mortality, complications, hospital stay and blood loss.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and the World Health Organization International Clinical Trials Registry Platform and the ClinicalTrials.gov trials registers to 30 November 2020. The review authors searched the Chinese Biomedical Literature Database and handsearched reference lists of relevant articles to identify additional trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that assessed the RP approach versus the TP approach for elective open abdominal aortic aneurysm (AAA) repair. There were no restrictions on language or publication status.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from the included trials. We resolved any disagreements through discussion with a third review author. Two review authors independently assessed the risk of bias in included trials with the Cochrane risk of bias tool. For dichotomous outcomes, we calculated the odds ratio (OR) with the corresponding 95% confidence interval (CI). For continuous data, we calculated a pooled estimate of treatment effect by calculating the mean difference (MD) and standard deviation (SD) with corresponding 95% CIs. We pooled data using a fixed-effect model, unless we identified heterogeneity, in which case we used a random-effects model. We used GRADE to assess the overall certainty of the evidence. We evaluated the outcomes of mortality, complications, intensive care unit (ICU) stay, hospital stay, blood loss, aortic cross-clamp time and operating time.

MAIN RESULTS

We identified no new studies from the updated searches. After reassessment, we included one study which had previously been excluded. Five RCTs with a combined total of 152 participants are included. The overall certainty of the evidence ranged from low to very low because of the low methodological quality of the included trials (unclear random sequence generation method and allocation concealment, and no blinding of outcome assessors), small sample sizes, small number of events, high heterogeneity and inconsistency between the included trials, no power calculations and relatively short follow-up. There was no evidence of a difference between the RP approach and the TP approach regarding mortality (odds ratio (OR) 0.32, 95% CI 0.01 to 8.25; 3 studies, 110 participants; very low-certainty evidence). Similarly, there was no evidence of a difference in complications such as hematoma (OR 0.90, 95% CI 0.13 to 6.48; 2 studies, 75 participants; very low-certainty evidence), abdominal wall hernia (OR 10.76, 95% CI 0.55 to 211.78; 1 study, 48 participants; very low-certainty evidence), or chronic wound pain (OR 2.20, 95% CI 0.36 to 13.34; 1 study, 48 participants; very low-certainty evidence) between the RP and TP approaches in participants undergoing elective open AAA repair. The RP approach may reduce ICU stay (mean difference (MD) -19.02 hours, 95% CI -30.83 to -7.21; 3 studies, 106 participants; low-certainty evidence); hospital stay (MD -3.30 days, 95% CI -4.85 to-1.75; 5 studies, 152 participants; low-certainty evidence); and blood loss (MD -504.87 mL, 95% CI -779.19 to -230.56; 4 studies, 129 participants; very low-certainty evidence). There was no evidence of a difference between the RP approach and the TP approach regarding aortic cross-clamp time (MD 0.69 min, 95% CI -7.23 to 8.60; 4 studies, 129 participants; very low-certainty evidence) or operating time (MD -15.94 min, 95% CI -34.76 to 2.88; 4 studies, 129 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

Very low-certainty evidence from five small RCTs showed no clear evidence of a difference between the RP approach and the TP approach for elective open AAA repair in terms of mortality, or for rates of complications including hematoma (very low-certainty evidence), abdominal wall hernia (very low-certainty evidence), or chronic wound pain (very low-certainty evidence). However, a shorter intensive care unit (ICU) stay and shorter hospital stay was probably indicated following the RP approach compared to the TP approach (both low-certainty evidence). A possible reduction in blood loss was also shown after the RP approach (very low-certainty evidence). There is no clear difference between the RP approach and TP approach in aortic cross-clamp time or operating time. Further well-designed, large-scale RCTs assessing the RP approach versus TP approach for elective open AAA repair are required.

A systematic review and meta-analysis on the management of concomitant abdominal aortic aneurysms and renal tumours

OBJECTIVES

The treatment of concomitant abdominal aortic aneurysms and renal tumours is controversial. The aim of this study was to ascertain which of the following three strategies, one-stage open aneurysm repair and nephrectomy, two-stage open aneurysm repair and nephrectomy or two-stage endovascular aneurysm repair and nephrectomy, is the best approach.

METHODS

systematic review and meta-analysis of articles published between January 1992 and April 2021 describing the treatment of concomitant abdominal aortic aneurysms and renal tumours.

RESULTS

A total of 1168 records were identified. After the selection process, 12 studies with data on 89 patients were included. Sixty-two patients underwent one-stage open procedures, 18 patients underwent two-stage open procedures and nine underwent two-stage endovascular procedures. The overall postoperative mortality was 0.82% (95% CI, 0.00-4.61). The postoperative mortality for one-stage open procedures was 3.09% (95% CI, 0.00-10.11). No deaths occurred in the postoperative period open two-stage procedures or two-stage endovascular procedures. The weighted postoperative morbidity for all procedures was 23.86% (95% CI, 12.64-35.08) and for open one-stage procedures was 37.40% (95% CI, 14.33-60.47). Data concerning postoperative complications of two-stage open procedures were extractable from only one patient in whom no complications were reported. Two postoperative complications were reported after two-stage endovascular procedures from a total of six patients with extractable postoperative data. We were unable to perform meta-analysis on long-term outcomes as the data were reported non-uniformly.

CONCLUSION

There is currently no evidence to suggest that any procedure is associated with better outcomes. However, a one-stage open approach was the most commonly used option, favoured as it avoids delaying treatment of either of the conditions. Two-stage open procedures were preferred in cases where the surgical risk of a one-stage procedure was higher than the potential benefit. For such cases, two-stage endovascular repair is becoming more popular as a less invasive approach.

Midterm Outcomes of a Prospective, Nonrandomized Study to Evaluate Endovascular Repair of Complex Aortic Aneurysms Using Fenestrated-Branched Endografts

OBJECTIVE

The aim of this study was to investigate the midterm outcomes of fenestrated and branched endovascular aortic repair (FB-EVAR) of pararenal (PRA) and thoracoabdominal aortic aneurysms (TAAAs).

SUMMARY BACKGROUND DATA

FB-EVAR has been associated with decreased morbidity compared to open repair, but there is limited midterm data.

METHODS

A total of 430 patients (302 males, mean age 74 ± 8 years) treated by FB-EVAR were enrolled in a prospective, nonrandomized investigational device exemption study. Endpoints included 30-day mortality and major adverse events (MAEs), freedom from all cause and aortic-related mortality, target vessel patency, and freedom from secondary intervention and target vessel instability.

RESULTS

There were 133 PRAs and 297 TAAAs with 1673 renal-mesenteric arteries incorporated by fenestrations or directional branches (3.9 ± 0.5 vessels/patient). At 30 days or within the hospital stay if longer than 30 days, there were 4 (0.9%) deaths. MAEs included new-onset dialysis in 8 patients (2%), permanent paraplegia or stroke in 10 patients each (2%), and respiratory failure requiring tracheostomy in 2 patients (0.5%). After a mean follow-up of 26 ± 20 months, there were 3 (0.7%) aortic-related deaths from SMA stent occlusion, gastrointestinal hemorrhage, or complications of open arch repair. At 5 years, freedom from all-cause and aortic-related mortality were 57% ± 5% and 98% ± 1%, respectively. Freedom from secondary intervention was 64% ± 4%, primary target vessel patency was 94% ± 1%, and freedom from target vessel instability was 89% ± 2% at same interval. One patient (0.2%) had nonfatal aneurysm treated using endovascular repair.

CONCLUSION

FB-EVAR is safe and effective for treatment of PRA and TAAAs with low rate of aortic-related mortality and aneurysm rupture on midterm follow-up.

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.

Inflammatory Gene Expression of Human Perivascular Adipose Tissue in Abdominal Aortic Aneurysms

OBJECTIVE

Perivascular adipose tissue (PVAT) contributes to vascular homeostasis and is increasingly linked to vascular pathology. PVAT density and volume were associated with abdominal aortic aneurysm (AAA) presence and dimensions on imaging. However, mechanisms underlying the role of PVAT in AAA have not been clarified. This study aimed to explore differences in PVAT from AAA using gene expression and functional tests.

METHODS

Human aortic PVAT and control subcutaneous adipose tissue were collected during open AAA surgery. Gene analyses and functional tests were performed. The control group consisted of healthy aorta from non-living renal transplant donors. Gene expression tests were performed to study genes potentially involved in various inflammatory processes and AAA related genes. Live PVAT and subcutaneous adipose tissue (SAT) from AAA were used for ex vivo co-culture with smooth muscle cells (SMCs) retrieved from non-pathological aortas.

RESULTS

Adipose tissue was harvested from 27 AAA patients (n [gene expression] = 22, n [functional tests] = 5) and five control patients. An increased inflammatory gene expression of PTPRC (p = .008), CXCL8 (p = .033), LCK (p = .003), CCL5 (p = .004) and an increase in extracellular matrix breakdown marker MMP9 (p = .016) were found in AAA compared with controls. Also, there was a decreased anti-inflammatory gene expression of PPARG in AAA compared with controls (p = .040). SMC co-cultures from non-pathological aortas with PVAT from AAA showed increased MMP9 (p = .033) and SMTN (p = .008) expression and SAT increased SMTN expression in these SMC.

CONCLUSION

The data revealed that PVAT from AAA shows an increased pro-inflammatory and matrix metallopeptidase gene expression and decreased anti-inflammatory gene expression. Furthermore, increased expression of genes involved in aneurysm formation was found in healthy SMC co-culture with PVAT of AAA patients. Therefore, PVAT from AAA might contribute to inflammation of the adjacent aortic wall and thereby plays a possible role in AAA pathophysiology. These proposed pathways of inflammatory induction could reveal new therapeutic targets in AAA treatment.

The Polymer-Based Technology in the Endovascular Treatment of Abdominal Aortic Aneurysms

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta that progressively grows until it ruptures. Treatment is typically recommended when the diameter is more than 5 cm. The EVAR (Endovascular aneurysm repair) is a minimally invasive procedure that involves the placement of an expandable stent graft within the aorta to treat aortic disease without operating directly on the aorta. For years, stent grafts' essential design was based on metallic stent frames to support the fabric. More recently, a polymer-based technology has been proposed as an alternative method to seal AAA. This review underlines the two platforms that are based on a polymer technology: (1) the polymer-filled endobags, also known as Endovascular Aneurysm Sealing (EVAS) with Nellix stent graft; and (2) the O-ring EVAR polymer-based proximal neck sealing device, also known as an Ovation stent graft. Polymer characteristics for this particular aim, clinical applications, and durability results are hereby summarized and commented critically. The technique of inflating endobags filled with polymer to exclude the aneurysmal sac was not successful due to the lack of an adequate proximal fixation. The platform that used polymer to create a circumferential sealing of the aneurysmal neck has proven safe and effective.

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.

Endovascular repair for abdominal aortic aneurysms

Management of abdominal aortic aneurysms has been the subject of rigorous scientific scrutiny. Prevalence studies have directed the formation of screening programmes, and observational studies and randomised controlled trials have defined aneurysm growth and treatment thresholds. Pre-emptive intervention with traditional open surgical repair has been the bedrock of improving long-term outcome and survival in patients with abdominal aortic aneurysms but it is associated with a significant procedural morbidity and mortality. Endovascular aneurysm repair (EVAR) has substantially reduced these early complications and has been associated with promising results in both elective and emergency aneurysm repair. However, the technique has brought its own unique complications, endoleaks. An endoleak is the presence of blood flow within the aneurysm sac but outside the EVAR graft. Although in randomised control trials EVAR was associated with a reduced early mortality compared with open repair, its longer-term morbidity and mortality was higher because endoleak development is associated with a higher risk of rupture. These endoleak complications have necessitated the development of postoperative imaging surveillance and re-intervention. These contrasting benefits and risks inform the selection of the mode of repair and are heavily influenced by individual patient factors. An improved strategy to predict endoleak development could further help direct treatment choice for patients and improve both early and late outcomes. This article reviews current EVAR practice, recent updates in clinical practice guidelines and the potential future developments to facilitate the selection of mode of aneurysm repair.Trial registration number: ClinicalTrials.gov NCT04577716.

A population-based study of post-endovascular aortic repair rupture during 15 years

OBJECTIVE

The devastating event of a ruptured abdominal aortic aneurysm (rAAA) in patients who have survived a previous AAA repair, either elective or urgent, is a feared and quite uncommon event. It has been suggested to partly explain the loss of the early survival benefit for endovascular aortic repair (EVAR) vs open surgical repair (OSR). The main objective of this study was to report the national incidence rate, risk factors and outcome of post-EVAR ruptures. Secondarily, the national incidence rate of ruptures after OSR (post-OSR ruptures) was investigated.

METHODS

We conducted a nationwide, population-based, retrospective cohort study using the inpatient and outpatient entries for all patients >40 years of age, receiving their first (index) surgical procedure for AAA, from 2001 to 2015. Only patients surviving their index procedure were included. The primary outcome was rAAA, registered after discharge from the index procedure (EVAR or OSR), identified in the Swedish National Patient Registry and the Cause of Death Registry.

RESULTS

In total, 14,859 patients survived their primary (index) AAA procedure. There were 6470 EVAR procedures, 5893 for intact AAA (iAAA) and 577 for rAAA. Of the 6470 EVAR patients, 86 cases of post-EVAR rupture were identified, corresponding with a cumulative incidence of 1.3% over a mean follow-up time of 3.9 years. The incidence rate was 3.4 (95% confidence interval [CI], 2.7-4.2)/1000 person-years. The independent risk factors identified for post-EVAR rupture were rAAA at index surgery HR 2.4 (95% CI, 1.4-4.1, p 0.002) and age (hazard ratio, 1.1; 95% CI, 1.0-1.1; P < .001). Freedom from post-EVAR rupture was 99%, 98%, and 96% at 3, 5, and 10 years, respectively. Total and postoperative mortality after post-EVAR rupture were 42% and 17% (30 days), 45% and 22% (90 days), and 53% and 33% (1 year). The incidence rate of post-OSR rupture was 0.9/1000 person-years (95% CI, 0.7-1.2).

CONCLUSIONS

Post-EVAR rupture is a rare complication that can occur at any time after the index EVAR procedure. This finding may have implications for the discussion of limited follow-up programs and for the choice of procedure in patients with an AAA with a long life expectancy. An rAAA as the indication for the index surgery and age were identified as risk factors for post-EVAR rupture. The mortality associated with post-EVAR rupture is high, but lower than that of primary rAAA. The much lower risk of post-OSR rupture was confirmed, but must not be neglected as a possible late complication.

Nationwide Study to Predict Colonic Ischemia after Abdominal Aortic Aneurysm Repair in The Netherlands

BACKGROUND

Colonic ischemia remains a severe complication after abdominal aortic aneurysm (AAA) repair and is associated with a high mortality. With open repair being one of the main risk factors of colonic ischemia, deciding between endovascular or open aneurysm repair should be based on tailor-made medicine. This study aims to identify high-risk patients of colonic ischemia, a risk that can be taken into account while deciding on AAA treatment strategy.

METHODS

A nationwide population-based cohort study of 9,433 patients who underwent an AAA operation between 2014 and 2016 was conducted. Potential risk factors were determined by reviewing prior studies and univariate analysis. With logistic regression analysis, independent predictors of intestinal ischemia were established. These variables were used to form a prediction model.

RESULTS

Intestinal ischemia occurred in 267 patients (2.8%). Occurrence of intestinal ischemia was seen significantly more in open repair versus endovascular aneurysm repair (7.6% vs. 0.9%; P < 0.001). This difference remained significant after stratification by urgency of the procedure, in both intact open (4.2% vs. 0.4%; P < 0.001) and ruptured open repair (15.0% vs. 6.2%); P < 0.001). Rupture of the AAA was the most important predictor of developing intestinal ischemia (odds ratio [OR], 5.9, 95% confidence interval [CI] 4.4-8.0), followed by having a suprarenal AAA (OR 3.4; CI 1.1-10.6). Associated procedural factors were open repair (OR 2.8; 95% CI 1.9-4.2), blood loss >1L (OR 3.6; 95% CI 1.7-7.5), and prolonged operating time (OR 2.0; 95% CI 1.4-2.8). Patient characteristics included having peripheral arterial disease (OR 2.4; 95% CI 1.3-4.4), female gender (OR 1.7; 95% CI 1.2-2.4), renal insufficiency (OR 1.7; 1.3-2.2), and pulmonary history (OR 1.6; 95% CI 1.2-2.2). Age <68 years proved to be a protective factor (OR 0.5; 95% CI 0.4-0.8). Associated mortality was higher in patients with intestinal ischemia versus patients without (50.6% vs. 5.1%, P < 0.001). Each predictor was given a score between 1 and 4. Patients with a score of ≥10 proved to be at high risk. A prediction model with an excellent AUC = 0.873 (95% CI 0.855-0.892) could be formed.

CONCLUSIONS

One of the main risk factors is open repair. Several other risk factors can contribute to developing colonic ischemia after AAA repair. The proposed prediction model can be used to identify patients at high risk for developing colonic ischemia. With the current trend in AAA repair leaning toward open repair for better long-term results, our prediction model allows a better informed decision can be made in AAA treatment strategy.

Epidemiology and management of aortic disease: aortic aneurysms and acute aortic syndromes

The aorta is the 'greatest artery', through which oxygenated blood is delivered from the left ventricle to end organs with each cardiac cycle (200 million litres of blood transported in an average lifetime). The aorta can be affected by a wide spectrum of acute factors (such as cocaine use, weight lifting and trauma) and chronic acquired and/or genetic conditions (such as systemic arterial hypertension and phaeochromocytoma), which variously lead to increased aortic wall stress. The medial layer of the aorta can also be subject to abnormalities (such as Marfan syndrome, bicuspid aortic valve, inflammatory vasculitis, atherosclerosis and infections). Despite important advances in diagnostic and therapeutic interventions, data derived from registries and population-based studies highlight that the burden of aortic diseases remains high. Therefore, specific resources need to be allocated to design and implement preventive strategies (healthy lifestyles, modifications to cardiovascular risk factors, and educational and screening programmes) at individual and community levels. In this Review, we discuss the epidemiology, management and outcomes of the most common aortic diseases, namely, aortic aneurysms and acute aortic syndromes.

Editor's Choice - Fenestrated or Branched Endovascular versus Open Repair for Complex Aortic Aneurysms: Meta-Analysis of Time to Event Propensity Score Matched Data

OBJECTIVE

The aim of this review was to investigate comparative outcomes of fenestrated or branched endovascular aneurysm repair (F/BEVAR) with open repair for juxta/para/suprarenal or thoraco-abdominal aortic aneurysms.

METHODS

Electronic bibliographic sources (MEDLINE and Embase) were interrogated using the Healthcare Databases Advanced Search interface. Eligible studies compared F/BEVAR with open repair for complex aortic aneurysms using propensity score or Cox regression modelling/multivariable logistic regression analysis. Pooled estimates of peri-operative outcomes were calculated using the odds ratio (OR) and 95% confidence interval (CI). The result of time to event analysis was reported as summary hazard ratio (HR) and 95% CI. Random effects models and the inverse variance method were applied. The quality of evidence was graded using the system developed by the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) working group.

RESULTS

Eleven studies published between 2014 and 2019 were selected for inclusion in qualitative and quantitative synthesis reporting a total of at least 7 061 patients. The odds of peri-operative mortality after F/BEVAR were lower, although not significantly, than after open repair (OR 0.56, 95% CI 0.28-1.12), whereas the hazard of overall mortality during follow up was higher following F/BEVAR, but, again, without reaching statistical significance (HR 1.25, 95% CI 0.93-1.67). The hazard of re-intervention was significantly higher after endovascular therapy (HR 2.11, 95% CI 1.39-3.18). The certainty for the body of evidence for peri-operative and overall mortality during follow up was judged to be very low and moderate, respectively, and for re-intervention it was judged to be high.

CONCLUSION

The evidence is uncertain about the effect of F/BEVAR on peri-operative mortality when compared with open repair. There is probably no difference in overall survival, but F/BEVAR results in an increased re-intervention hazard. There is a need for high level evidence to inform decision making and vascular/aortic service provision.

Biomechanical rupture risk assessment of abdominal aortic aneurysms using clinical data: A patient-specific, probabilistic framework and comparative case-control study

We present a data-informed, highly personalized, probabilistic approach for the quantification of abdominal aortic aneurysm (AAA) rupture risk. Our novel framework builds upon a comprehensive database of tensile test results that were carried out on 305 AAA tissue samples from 139 patients, as well as corresponding non-invasively and clinically accessible patient-specific data. Based on this, a multivariate regression model is created to obtain a probabilistic description of personalized vessel wall properties associated with a prospective AAA patient. We formulate a probabilistic rupture risk index that consistently incorporates the available statistical information and generalizes existing approaches. For the efficient evaluation of this index, a flexible Kriging-based surrogate model with an active training process is proposed. In a case-control study, the methodology is applied on a total of 36 retrospective, diameter matched asymptomatic (group 1, n = 18) and known symptomatic/ruptured (group 2, n = 18) cohort of AAA patients. Finally, we show its efficacy to discriminate between the two groups and demonstrate competitive performance in comparison to existing deterministic and probabilistic biomechanical indices.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Current status on aortic endografts

Endovascular treatment has become widespread to treat aneurysmal disease, especially located in the aorta. The modern era of abdominal aortic aneurysm repair started between 1986 and 1991, and in the last 30 years, Endovascular Treatment for abdominal aortic aneurysms evolved both due to the development of new materials and devices and the increasing appeal and effectiveness of the endovascular therapy itself. Vascular surgeons are using nowadays different solutions of Endovascular Treatment to treat all the expressions of aortic pathology (aneurysms, dissections and trauma) both in the acute and elective setting. Despite its use in every location of the aorta (the ascending aorta, the aortic arch, the thoracic aorta, thoraco-abdominal aorta, pararenal, iuxtarenal and infrarenal aortic aneurysms and iliac aneurysms), its safety and efficiency, endovascular treatment for aortic aneurysms presents some drawbacks: despite a lower short-term morbi-mortality, reinterventions and long-term patency are higher compared to open repair. In this review, we detail the most used types of endografts according to location, their performances and durability for each device. We conclude by discussing options to overcome ET limitations. Therefore, an obvious question arises: what we need in the future? What can the technological progress gives to physicians to further improve this new way of treating aorta?

Impact of Gradual Adoption of EVAR in Elective Repair of Abdominal Aortic Aneurysm: A Retrospective Cohort Study from 2009 to 2015

INTRODUCTION

The recommendations about the preferred type of elective repair of abdominal aortic aneurysm (AAA) still divides guidelines committees, even nowadays. The aim is to assess outcomes after AAA repair focusing on differences between endovascular aneurysm repair (EVAR) and open surgical repair (OSR).

METHODS

The observational retrospective cohort study of consecutive patients submitted to elective AAA repair at a tertiary center, 2009-2015. Exclusion criteria were as follows: nonelective cases or complex aortic aneurysms. Primary outcomes were postoperative complications, length of hospital stay, survival, freedom from aortic-related mortality, and vascular reintervention. Time trends were assessed along the period under analysis.

RESULTS

From a total of 211 included patients, those submitted to EVAR were older (74 ± 7 vs. 67 ± 9 years; P < 0.001), presented a higher prevalence of hypertension (83.5% vs. 68.5%, P = 0.004), obesity (28.7% vs. 14.3%, P = 0.029), previous cardiac revascularization (30.5% vs. 14.7%, P = 0.005), heart failure (17.2% vs. 5.2%, P = 0.013), and chronic obstructive pulmonary disease (32.8% vs. 13.3%, P = 0.002). Patients were followed during a median of 49 months. EVAR resulted in a significantly shorter length of hospital stay (median 4 and interquartile range 3 vs. 8 (9); P < 0.001), lower 30-day complications (10.6% vs. 22.8%, P = 0.017), lower aortic-related mortality, and similar reintervention after adjustment with a propensity score. Along the time under analysis, EVAR became the predominate type of repair (P = 0.024), the proportion of complications decreased (P = 0.014), and the 30-day mortality (P = 0.035).

CONCLUSIONS

Although EVAR was offered to patients with more comorbidities, better and durable outcomes were achieved after EVAR, favoring its adoption for elective AAA repair.

Prognostic Significance of Aneurysm Sac Shrinkage After Endovascular Aneurysm Repair

Purpose: To investigate whether patients who develop aneurysm sac shrinkage following endovascular aneurysm repair (EVAR) have better outcomes than patients with a stable or increased aneurysm sac. Materials and Methods: The Healthcare Databases Advanced Search interface developed by the National Institute for Health and Care Excellence was used to interrogate MEDLINE and EMBASE. Thesaurus headings were adapted accordingly. Case-control studies were identified comparing outcomes in patients demonstrating aneurysm sac shrinkage after EVAR with those of patients with a stable or expanded aneurysm sac. Pooled estimates of dichotomous outcome data were calculated using the odds ratio (OR) and 95% confidence interval (CI). Meta-analysis of time-to-event data was conducted using the inverse-variance method; the results are reported as a summary hazard ratio (HR) and 95% CI. Summary outcome estimates were calculated using random-effects models. Results: Eight studies were included in quantitative synthesis reporting a total of 17,096 patients (8518 patients with sac shrinkage and 8578 patients without sac shrinkage). The pooled incidence of sac shrinkage at 12 months was 48% (95% CI 40% to 56%). Patients with aneurysm sac shrinkage had a significantly lower hazard of death (HR 0.73, 95% CI 0.60 to 0.87), secondary interventions (HR 0.42, 95% CI 0.29 to 0.62), and late complications (HR 0.37, 95% CI 0.24 to 0.56) than patients with a stable or increased aneurysm sac. Furthermore, their odds of rupture were significantly lower than those in patients without shrinkage (OR 0.09, 95% CI 0.02 to 0.36). Conclusion: Sac regression is correlated to improved survival and a reduced rate of secondary interventions and EVAR-related complications. The prognostic significance of sac regression should be considered in surveillance strategies. Intensified surveillance should be applied in patients who fail to achieve sac regression following EVAR.