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Ashraf F, Ambreen T, Park CW, Kim DI. Comparative evaluation of ballet-type and conventional stent graft configurations for endovascular aneurysm repair: A CFD analysis. Clin Hemorheol Microcirc 2021; 78:1-27. [PMID: 33459700 PMCID: PMC8293652 DOI: 10.3233/ch-200996] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE: Cross limb stent graft (SG) configuration technique for endovascular aneurysm repair (EVAR) is employed for splayed aortic bifurcations to avoid device kinking and smoothen cannulation. The present study investigates three types of stent graft (SG) configurations for endovascular aneurysm repair (EVAR) in abdominal aortic aneurysm. A computational fluid dynamic analysis was performed on the pulsatile non-Newtonian flow characteristics in three ideally modeled geometries of abdominal aortic (AA) SG configurations. METHODS: The three planar and crosslimb SG configurations were ideally modeled, namely, top-down nonballet-type, top-down ballet-type, and bottom-up nonballet-type configurations. In top-down SG configuration, most of the device is deployed in the main body in the vicinity of renal artery and the limbs are extended to the iliac artery. While in the bottom-up configuration, some of the SG device is deployed in the main body, the limbs are deployed in aortic bifurcation, and the extra stent graft of the main body is extended to the proximal aorta until the below of the renal artery. The effects of non-Newtonian pulsatile flow on the wall stresses and flow patterns of the three models were investigated and compared. Moreover, the average wall shear stress (AWSS), oscillatory shear stress index (OSI), absolute helicity, pressure distribution, graft displacement and flow visualization plots were analyzed. RESULTS: The top-down ballet-type showed less branch blockage effect than the top-down nonballet-type models. Furthermore, the top-down ballet-type configuration showed an increased tendency to sustain high WSS and higher helicity characteristics than that of the bottom-up and top-down non-ballet type configurations. However, displacement forces of the top-down ballet-type configuration were 40% and 9.6% higher than those of the bottom-up and top-down nonballet-type configurations, respectively. CONCLUSIONS: Some complications such as graft tearing, thrombus formation, limb disconnection during long term follow up periods might be relevant to hemodynamic characteristics according to the configurations of EVAR. Hence, the reported data required to be validated with the clinical results.
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Affiliation(s)
- Fahmida Ashraf
- School of Mechanical Engineering, Kyungpook National University, Daegu, South Korea
| | - Tehmina Ambreen
- School of Mechanical Engineering, Kyungpook National University, Daegu, South Korea
| | - Cheol Woo Park
- School of Mechanical Engineering, Kyungpook National University, Daegu, South Korea
| | - Dong-Ik Kim
- Division of Vascular Surgery, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, South Korea
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Law Y, Chan YC, Cheng SW. Delayed open conversion after endovascular aortic repair. Asian Cardiovasc Thorac Ann 2018; 27:80-86. [PMID: 30563352 DOI: 10.1177/0218492318820195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
AIM We present the clinical outcomes of patients who underwent delayed (>30 days) open surgical repair after endovascular aortic aneurysm repair. METHODS All patients receiving delayed open repair of infrarenal and juxtarenal aortic aneurysms after endovascular repair from July 2001 to December 2017 were retrospectively reviewed. Patients' baseline characteristics, indications for delayed open conversion, and time between endovascular repair and open conversion are described. Early outcomes included operative approach, morbidity, and mortality. Midterm outcomes included survival. RESULTS Twenty-two (3.3%) of 667 patients with prior infrarenal endovascular aortic aneurysm repair had delayed open conversion (20 elective and 2 emergency). The time from endovascular repair to open conversion was 60 ± 36 months. The indications were 6 (27%) type Ia endoleaks, 6 (27%) type II endoleaks with enlarging sac size, 2 (9%) endotensions, 7 (32%) unknown types of endoleak, and 1 (5%) graft infection. The 7 minutes unknown endoleaks were confirmed as lumbar leaks in 4 cases and fabric leaks in 3. Operative time was 222 ± 48 min with blood loss of 2211 ± 2057 mL. Hospital stay after conversion was 12 ± 8 days. There was no 30-day mortality. Estimated survival rates were 96%, 91%, 86%, 79% and 57% at 1, 2, 3, 4, and 5 years postoperatively. CONCLUSION Delayed conversion to open surgery after endovascular aortic aneurysm repair by endograft explantation appears to be safe with good short- and mid-term outcomes. With careful preoperative assessment, open conversion remained a realistic and viable option in patients with failed endovascular treatment.
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Affiliation(s)
- Y Law
- Division of Vascular Surgery, Department of Surgery, The University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong
| | - Y C Chan
- Division of Vascular Surgery, Department of Surgery, The University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong
| | - S W Cheng
- Division of Vascular Surgery, Department of Surgery, The University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong
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Open versus Endovascular Repair of Abdominal Aortic Aneurysm in the Elective and Emergent Setting in a Pooled Population of 37,781 Patients: A Systematic Review and Meta-Analysis. ISRN CARDIOLOGY 2014; 2014:149243. [PMID: 25006502 PMCID: PMC4004021 DOI: 10.1155/2014/149243] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 02/03/2014] [Indexed: 01/09/2023]
Abstract
Background. We evaluated the incidence of mortality and myocardial infarction (MI) in endovascular repair (EVAR) as compared to open aneurysm repair (OAR) in both elective and ruptured abdominal aortic aneurysm (AAA ) setting. Methods. We analyzed the rates of 30-day mortality, 30-day MI, and hospital length of stay (LOS) based on comparative observation and randomized control trials involving EVAR and OAR. Results. 41 trials compared EVAR to OAR with a total pooled population of 37,781 patients. Analysis of elective and ruptured AAA repair favored EVAR with respect to 30-day mortality with a pooled odds ratio of 0.19 (95% CI 0.17–0.20; I2 = 88.9%; P < 0.001). There were a total of 1,835 30-day MI events reported in the EVAR group as compared to 2,483 events in the OAR group. The pooled odds ratio for elective AAA was 0.74 (95% CI 0.58–0.96; P = 0.02) in favor of EVAR. The average LOS was reduced by 296.75 hrs (95% CI 156.68–436.82 hrs; P < 0.001) in the EVAR population. Conclusions. EVAR has lower rates of 30-day mortality, 30-day MI, and LOS in both elective and ruptured AAA repair.
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Stather PW, Sidloff D, Dattani N, Choke E, Bown MJ, Sayers RD. Systematic review and meta-analysis of the early and late outcomes of open and endovascular repair of abdominal aortic aneurysm. Br J Surg 2013; 100:863-72. [DOI: 10.1002/bjs.9101] [Citation(s) in RCA: 249] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2013] [Indexed: 12/18/2022]
Abstract
Abstract
Background
Any possible long-term benefit from endovascular (EVAR) versus open surgical repair for abdominal aortic aneurysm (AAA) remains unproven. Long-term data from the Open Versus Endovascular Repair (OVER) trial add to the debate regarding long-term all-cause and aneurysm-related mortality. The aim of this study was to investigate 30-day and long-term mortality, reintervention, rupture and morbidity after EVAR and open repair for AAA in a systematic review.
Methods
Standard PRISMA guidelines were followed. Random-effects Mantel–Haenszel meta-analysis was performed to evaluate mortality and morbidity outcomes.
Results
The existing published randomized trials, together with information from Medicare and SwedVasc databases, were included in a meta-analysis. This included 25 078 patients undergoing EVAR and 27 142 undergoing open repair for AAA. Patients who had EVAR had a significantly lower 30-day or in-hospital mortality rate (1·3 per cent versus 4·7 per cent for open repair; odds ratio (OR) 0·36, 95 per cent confidence interval 0·21 to 0·61; P < 0·001). By 2-year follow-up there was no difference in all-cause mortality (14·3 versus 15·2 per cent; OR 0·87, 0·72 to 1·06; P = 0·17), which was maintained after at least 4 years of follow-up (34·7 versus 33·8 per cent; OR 1·11, 0·91 to 1·35; P = 0·30). There was no significant difference in aneurysm-related mortality by 2 years or longer follow-up. A significantly higher proportion of patients undergoing EVAR required reintervention (P = 0·003) and suffered aneurysm rupture (P < 0·001).
Conclusion
There is no long-term survival benefit for patients who have EVAR compared with open repair for AAA. There are also significantly higher risks of reintervention and aneurysm rupture after EVAR.
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Affiliation(s)
- P W Stather
- Vascular Surgery Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - D Sidloff
- Vascular Surgery Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - N Dattani
- Vascular Surgery Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - E Choke
- Vascular Surgery Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - M J Bown
- Vascular Surgery Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- Leicester National Institute for Health Research Cardiovascular Biomedical Research Unit, Leicester, UK
| | - R D Sayers
- Vascular Surgery Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
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Molony DS, Kavanagh EG, Madhavan P, Walsh MT, McGloughlin TM. A computational study of the magnitude and direction of migration forces in patient-specific abdominal aortic aneurysm stent-grafts. Eur J Vasc Endovasc Surg 2010; 40:332-9. [PMID: 20573524 DOI: 10.1016/j.ejvs.2010.06.001] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Accepted: 06/03/2010] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Endovascular aneurysm repair for abdominal aortic aneurysm (AAA) is now a widely adopted treatment. Several complications remain to be fully resolved and perhaps the most significant of these is graft migration. Haemodynamic drag forces are believed to be partly responsible for migration of the device. The objective of this work was to investigate the drag forces in patient-specific AAA stent-grafts. METHODS CT scan data was obtained from 10 post-operative AAA patients treated with stent-grafts. 3D models of the aneurysm, intraluminal thrombus and stent-graft were created. The drag forces were determined by fluid-structure interaction simulations. A worst case scenario was investigated by altering the aortic waveforms. RESULTS The median resultant drag force was 5.46 N (range: 2.53-10.84). An increase in proximal neck angulation resulted in an increase in the resultant drag force (p = 0.009). The primary force vector was found to act in an anterior caudal direction for most patients. The worst case scenario simulation resulted in a greatest drag force of 16 N. CONCLUSIONS Numerical methods can be used to determine patient-specific drag forces which may help determine the likelihood of stent-graft migration. Anterior-posterior neck angulation appears to be the greatest determinant of drag force magnitude. Graft dislodgement may occur anteriorally as well as caudally.
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Affiliation(s)
- D S Molony
- Centre for Applied Biomedical Engineering Research, Department of Mechanical and Aeronautical Engineering and Materials and Surface Science Institute, University of Limerick, Ireland
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Endovascular Abdominal Aortic Aneurysm Repair: Part I. Ann Vasc Surg 2009; 23:799-812. [DOI: 10.1016/j.avsg.2009.03.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Accepted: 03/21/2009] [Indexed: 12/20/2022]
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Lovegrove RE, Javid M, Magee TR, Galland RB. A meta-analysis of 21 178 patients undergoing open or endovascular repair of abdominal aortic aneurysm. Br J Surg 2008; 95:677-84. [DOI: 10.1002/bjs.6240] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Abstract
Background
Several studies have compared outcomes after elective open and endovascular approaches to abdominal aortic aneurysm (AAA) surgery, with varying results.
Methods
A random-effects meta-analysis was undertaken to compare operative outcomes, postoperative complications, 30-day mortality and long-term patient survival after surgery. Endpoints were compared using odds ratios (ORs), weighted mean differences (WMDs) or log hazard ratios (HRs) as appropriate.
Results
Forty-two studies comprising 21 178 patients (10 855 open; 10 323 endovascular) were included. In the elective setting (20 715 patients), the endovascular method was associated with a shorter stay in intensive care (WMD − 36 h; P < 0·001) and a shorter total postoperative stay (WMD − 5·4 days; P < 0·001). Cardiac (OR 1·76; P = 0·002) and respiratory (OR 4·01; P < 0·001) complications were more common after open surgery. In the endovascular group, 30-day mortality was lower (OR 0·46; P < 0·001). Endovascular surgery was also associated with an improved long-term aneurysm-related mortality (HR 0·39; P < 0·001). For ruptured AAA (463 patients), the less invasive operation was associated with a reduced stay in intensive care (WMD − 100·4 h; P = 0·005) and a significantly lower 30-day mortality (OR 0·45; P = 0·005).
Conclusions
The endovascular repair of AAA offers a clear benefit in terms of reduction in postoperative adverse events and 30-day mortality. In the longer term, it is also associated with a reduction in aneurysm-related mortality, but not in all-cause mortality.
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Affiliation(s)
- R E Lovegrove
- Department of General Surgery, Royal Berkshire Hospital, London Road, Reading RG1 5AN, UK
| | - M Javid
- Department of General Surgery, Royal Berkshire Hospital, London Road, Reading RG1 5AN, UK
| | - T R Magee
- Department of General Surgery, Royal Berkshire Hospital, London Road, Reading RG1 5AN, UK
| | - R B Galland
- Department of General Surgery, Royal Berkshire Hospital, London Road, Reading RG1 5AN, UK
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De Rango P, Cao P, Parlani G, Verzini F, Brambilla D. Outcome after endografting in small and large abdominal aortic aneurysms: a metanalysis. Eur J Vasc Endovasc Surg 2008; 35:162-72. [PMID: 18069023 DOI: 10.1016/j.ejvs.2007.10.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Accepted: 10/17/2007] [Indexed: 10/22/2022]
Abstract
AIM To compare the results of endovascular repair (EVAR) in large and small (diameter < 5.5cm) abdominal aortic aneurysms (AAA). METHODS A systematic review was performed to identify studies comparing the outcomes after EVAR of large and small aneurysms. Outcomes considered were: risk of death (perioperative, all cause, aneurysm-related), ruptures, and complications (conversion, reintervention). Weighted pooled estimates of outcomes in patients with small versus large aneurysms were calculated. The inverse variance method was used (random-effect model). Subgroup analyses by a follow-up longer or shorter than 24 months were performed. RESULTS Five studies, with published and unpublished data, totallying 7,735 patients, were included. Overall, the weighted pooled estimates were: OR 0.68; 95% CI 0.51-0.90 for operative mortality, OR 0.77; 95% CI 0.69 to 0.86 for all cause mortality, OR 0.58; 95% CI 0.40 to 0.87 for aneurysm-related mortality and OR 0.61; 95% CI 0.47 to 0.79 for rupture in favour of small AAA group. Pooled estimates were not influenced by follow-up length. Conversion and reintervention rates were not significantly lower for small AAA. CONCLUSIONS EVAR in small versus large AAA might be associated with lower operative mortality, aneurysm-related mortality and aneurysm rupture. Better evidence is needed to support these suggestions.
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Affiliation(s)
- P De Rango
- Division of Vascular and Endovascular Surgery, University of Perugia, Ospedale S. Maria della Misericordia, Perugia, Italy
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