Early and mid-term results of endovascular abdominal aortic aneurysm repair with hostile proximal neck anatomy
AbstractBackground. Currently, there are no exact recommendations on the possibility of performing endovascular repair of an abdominal aortic aneurysm if the requirements for the anatomy of its proximal neck go beyond the recommended criteria.
Objective. The aim of our study was to evaluate the immediate and mid-term results of endovascular repair of an abdominal aneurysm with hostile anatomy of its proximal neck.
Patients and methods. We retrospectively analyzed therapeutic outcomes in 88 patients who underwent endovascular abdominal aortic aneurysm repair with a hostile proximal landing zone. The stent grafts implanted into the patients were as follows: Seal, Zenith Alpha, ELLA, Ovation Prime, Anaconda, Endurant. The outcome measures comprised the incidence of clinically significant complications, reoperations, and mortality within 2 years after surgery.
Results. The study included a total of 88 patients, of whom there were 75 (85%) men and 13 (15%) women. A conical neck of the aneurysm was present in 12 (14) patients. Parietal thrombotic masses in the zone of proximal fixation were moderately pronounced (<50% of the circumference) in 33 (38%) cases and significantly pronounced (50% and more of the circumference) in eight (9%) cases. Moderate angulation from 60° to 75° was observed in ten (11%) patients, with pronounced neck angulation of 75° and more encountered in six (7%) patients. Calcification of more than 50% of the cervical circumference was observed in 66 (75%) patients. An aneurysm neck length of less than 10 mm was observed in four (5%) cases.
The technical success of the operation was achieved in 98.86% of cases. One (1%) patient developed thrombosis of the endograft limb in the early postoperative period. The 2-year primary patency of the stent-grafts was 82.95%. The total number of endoleaks during the in-hospital and mid-term postoperative periods did not differ significantly, amounting to 20 (22.72%) and 24 (27.27%), respectively (p=0.60). The presence of parietal thrombotic masses in the area of the proximal neck increased the risk of thrombosis of the stent-graft limbs in the postoperative period [RR 5.03 (1.28; 19.81), p=0.02]. Angulation of the proximal aneurysm neck elevated the risk of endoleaks [RR 1.55 (1.06; 5.30), p=0.04].
Conclusion. Endovascular abdominal aortic aneurysm repair in hostile anatomy of the proximal landing zone is a safe and effective method of treatment, with a technical success rate of 98.86%. It was found that angulation in the area of the proximal aneurysmal neck contributed to the development of endoleaks in the mid-term follow-up period, with thrombotic masses in the region of the proximal neck of the aneurysm being predictive factors for thrombosis of the stent-graft limbs.
Funding. This study was financially supported by the Russian Science Foundation grant 21-15-00091.
Conflict of interest. The authors declare no conflicts of interest.
Authors’ contribution. Study conception and design – Karpenko A.A., Rabtsun A.A., Osipova O.S., Ignatenko P.V.; data collection and handling – Rabtsun A.A., Efimova–Syakina K.A., Osipova O.S., Cheban A.V., Gostev A.A., Saaya Sh.B.; statistical processing – Rabtsun A.A., Gostev A.A., Osipova O.S., Saaya Sh.B.; draft manuscript preparation – Osipova O.S., Rabtsun A.A., Efimova-Syakina K.A.; manuscript revision – Karpenko A.A., Osipova O.S., Ignatenko P.V.
Acknowledgments. The authors express their sincere thanks to Aivazov Sakhib Allaz ogly, a resident physician of the “Novosibirsk State Medical University” of the RF Ministry of Public Health, for help in data collection.
For citation: Osipova O.S., Rabtsun A.A., Efimova–Syakina K.A., Cheban A.V., Gostev A.A., Saaya Sh.B., Ignatenko P.V., Karpenko A.A. Early and mid-term results of endovascular abdominal aortic aneurysm repair with hostile proximal neck anatomy. Angiology and Vascular Surgery. Journal named after Academician A.V. Pokrovsky. 2023; 29 (4): 102–7. DOI: https://doi.org/10.33029/1027-6661-2023-29-4-102-107
Keywords:aorta; aneurysm; endovascular treatment; endovascular aneurysm repair; stent-graft
Introduction
Endovascular repair of infrarenal aortic aneurysms has proved to be a reliable alternative to open surgical correction. This is first of all due to the creation of high-technology devices owing to which the operation has become mainstream, with minimum mortality in both early and late postoperative periods [1].
At the same time, the technical success of the operation and stable clinical outcomes can only be achieved in favourable anatomical conditions. Of the latter, the main is the proximal stent graft landing zone, which must ensure reliable sealing of the place of coupling of the implanted device with the adjacent vascular wall and minimise the risk of the device migration during its long stay inside the vascular lumen. The success of the procedure also depends on the diameter of iliac arteries through which stent-graft’s components are delivered to the implantation zone and eventually ensure successful sealing of the distal zone of the device contact with iliac arteries [2].
Depending on the endograft design, anatomical constraints of the aneurysm to be stented are determined. Given the primary importance of aneurysmal sac sealing in the proximal landing zone, the possibility of carrying out the procedure is determined by the diameter and length of the infrarenal aortic portion, its tortuosity, the presence of parietal thrombosis, calcification, and the so-called prismatic (flaring downward) shape of the aortic neck [3].
Broadening the indications for stent graft implantation outside the instruction for use anatomical limits influences the technical success of the procedure, increasing the risk of developing short- and long-term postoperative complications. At the same time in comorbid and aged patients, open surgical correction due to traumaticity and the necessity in many patients of cross-clamping of the aorta above the renal arteries (RA) during formation of the central anastomosis is also accompanied by an increased risk of early postoperative complications and lethal outcomes. Therefore, some patients undergo endovascular repair of an abdominal aortic aneurysm with anatomical parameters beyond the limits recommended by manufacturing companies [4].
The purpose of our study was to evaluate the immediate and mid-term results of endovascular repair of an abdominal aneurysm with hostile anatomy of its proximal neck.
Patients and methods
We retrospectively analyzed therapeutic outcomes in a total of 88 patients who underwent endovascular abdominal aortic aneurysm repair with a hostile proximal landing zone. The stent grafts were implanted via 2 accesses to the common femoral arteries (CFA) on both sides. The main body of the endograft and its additional branches were inserted through the CFA.
The endograft size and manufacturing companies were selected according to the individual anatomy of the aneurysmal sac and arteries of access, as well as the possibilities of the clinic purchasing the device.
Assessment of the nature of the lesion of the aortic infrarenal portion and calculation of the sent-graft’s sizes were carried out analyzing contrast-enhanced multispiral computed tomography (MSCT) of the aorta, iliac and femoral arteries, with slice thickness not more than 1 mm.
To evaluate the clinical results, the following variables were included into the database: baseline patient characteristics, accompanying diseases, aneurysmal anatomy, endovascular intervention protocol data, postoperative follow-up and the findings of aortic ultrasound examination and MSCT-angiography in the early postoperative period, as well as at 6, 12 and 24 months thereafter.
Inclusion criteria: infrarenal aneurysms of the aorta or aortoiliac aneurysms (asymptomatic and symptomatic, uncomplicated) with a transverse diameter exceeding 5.5 cm. Aneurysms with anatomy of the proximal landing zone going beyond the instruction for use attached to a stent graft concerned.
Exclusion criteria: pronounced tortuosity, calcification and the diameter of iliac arteries less than 6 mm, diameter of the proximal aortic neck more than 32 mm. We did not include patients with the diameter of the proximal neck more than 32 mm because we did not have available stent grafts with the diameter of the proximal landing zone more than 32 mm. Using stent grafts with smaller diameter of the proximal landing zone in this case would have knowingly resulted in failed operation and put the patient at unjustified risk.
The recommended limit characteristics of the proximal landing zone for the stent grafts used are shown in Table 1.
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The decision to perform an endovascular procedure was made by a multidisciplinary team consisting of a vascular surgeon, cardiologist and anesthesiologist, with a thorough assessment of the risk of intraoperative and early postoperative complications in performing an open surgical operation.
The endografts were implanted in a surgical operating room equipped with the high-resolution angiographic unit Innova 3100 (GE HealthCare, USA). The aorta was visualized with the help of intraoperative administration of iodine-containing contrast media (Ultravist-370, Visipaque, Iopamiro 370, Optirey, Xenetx 350, Scanlux 370). Endografts were implanted according to the standard technique. In aseptic conditions under local anesthesia, open surgical access to the right and left CFA was performed, followed by puncture of the CFA anterior wall on both sides with inserting into the arterial lumen introducers 7 Fr, through which angiography of the iliac arteries was performed in order to visualize their anatomy and ostia of the internal iliac arteries. As the next stage, from the side of inserting the main body of the stent graft through iliac arteries and aortic aneurysm, into its suprarenal portion we inserted an angiographic catheter and through its lumen under fluorographic control into the ascending aorta we placed with the distal end a super stiff angiographic guidewire 0.035” in diameter (Lunderquist Extra Stiff Wire Guide, William Cook Europe, Bjaeveskov, Denmark). To control the RA ostia, via the access in the right brachial artery, through the subclavian artery, brachiocephalic trunk and thoracic aorta we inserted a pigtail catheter 0.35 mm to be deployed with the inner end slightly above the proximally located ostium of the RA.
The introducers were then alternatively retrieved from the femoral arteries, followed by inserting into the aorta the main body of the stent graft to be positioned with the proximal coating border immediately beneath the lumen of the distally situated RA. Expansion of the stent graft body was followed by catheterization of its contralateral leg and implantation of the extension into the respective iliac artery.
The implanted stent grafts were as follows: Seal, Zenith Alpha, ELLA, Ovation Prime, Anaconda, Endurant (Fig. 1).
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The technical success of the operation was defined as successful implantation of all components of the endograft without stent graft migration in the proximal zone of fixation and no need to switch to open surgery.
Successfulness of endovascular treatment of abdominal aorta aneurysms was evaluated by the frequency of clinically significant complications, re-interventions and mortality on POD 3–5, at 6, 12 and 24 months, as well as by the findings of color duplex mapping of arteries, telephone interviewing, ultrasonography and/or MSCT angiography.
Accumulation and primary sorting of data were performed using Microsoft Excel 2010. Analysis of surgical treatment was carried out with the use of SPSS Statistica 12 (StatSoft, Inc, USA). Quantitative data were presented as mean ± standard deviation and categorical data as percentage (%). The categorical variables were compared using the two-tailed Fisher’s exact test. Anatomical predictors of endoleaks and thromboses of stent graft limbs in the postoperative period were analyzed by means of the univariate and multivariate Cox regression analysis. Differences were regarded as statistically significant if p<0.05.
Results
Patient characteristics
The study included a total of 88 patients, of whom there were 75 (85%) men and 13 (15%) women (mean age 67±6.17 years). Distribution of the patients by accompanying pathology is shown in Table 2.
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All operations were performed electively. In 92% of patients, the course of aneurysms was asymptomatic, with fusiform aneurysms accounting for 96%.
A conical neck (dilatation of the neck by not less than 3 mm along a length of 20 mm from the inferior RA) was present in 12 (14%) patients.
Parietal thrombotic masses in the zone of proximal fixation were moderately pronounced (<50% of the circumference) in 33 (38%) patients and significantly pronounced (50% and more of the circumference) in eight (9%) patients.
Moderate angulation from 60° to 75° was observed in ten (11%) patients, with pronounced neck angulation of 75° and more encountered in six (7%) patients.
Calcification of more than 50% of the cervical circumference was observed in 66 (75%) patients. An unsatisfactory aneurysm neck length of less than 10 mm was observed in four (5%) patients. The presence of one criterion of hostile anatomy of the aneurysmal neck was observed in 6 (7%) patients, a combination of 2 factors – in 11 (13%), 3 factors – in 26 (29%), four factors – in 26 (29%) and 5 factors – in 19 (22%) patients.
The duration of the follow-up period was 24 months.
Procedural and early results
The technical success of the operations was achieved in 98.8%. All 88 patients received implantation of all stent graft’s components. Migration of graft components in the zone of proximal fixation occurred in 1 patient with angulation of the proximal neck less than 60° and in 2 – in the zone of distal fixation. In migration of components in the distal zone of fixation, no additional interventions were performed. Iliac-renal bypassing was performed for stent graft components migration in the area of proximal fixation zone with covering of the RA ostium by the graft fabric.
Six (7%) patients during endovascular repair of abdominal aortic aneurysms underwent the following planned procedures: occlusion of the internal iliac artery with spirals – 1 (1%), endarterectomy from the CFA – 1 (1%), stenting of the RA – 3 (3%), balloon angioplasty of the iliac artery with stenting – 1 (1%).
The average duration of the operation amounted to 150 minutes. The median of the volume of the administered contrast medium was 250 ml.
The mean levels of creatinine and urea were 99 mmol/L and 6.2 mmol/L prior to operation; on POD 1 – 100 and 6.3 mmol/L, before discharge – 94 and 5.6 mmol/L, respectively. In dynamics, urea and creatinine levels naturally increased on POD 1 and decreased to the baseline values at discharge. The average length of hospital stay amounted to 10 days.
One (1%) patient in the early postoperative period developed stent graft limb thrombosis, another one (1%) developed thrombosis of peripheral arteries. Four (5%) patients with baseline concomitant chronic kidney disease, after surgery were found to have a decrease in the glomerular filtration rate. Two (2%) patients postoperatively demonstrated progression of chronic lower-extremity ischemia.
Eight (9%) patients after surgery were diagnosed as having anemia, with positive dynamics observed on the background of conservative therapy – the patients were discharged in a satisfactory condition. In two (2%) patients, hematoma was revealed in the access zone, requiring no additional operation. There were no infectious complications in the access zones.
One (1%) patient died from myocardial infarction.
During the in-hospital period, the findings of ultrasonography and MACT angiography of the abdominal aortic portion and lower-limb arteries demonstrated endoleaks in 20 (23%) patients: type IA endoleak was registered in 8 (%), type IB – in 4 (5%), type II – in 4 (5%), type III and IV in – 2 (2%) patients, respectively.
Mid-term results
In the remote period of follow-up, the number of type I endoleaks did not change, however with an increased number of type II endoleaks and a decreased number of type III and type IV endoleaks. The total number of endoleaks in the early and mid-term postoperative periods did not differ significantly. The change in the number of endoleaks is shown in Fig. 2.
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The 2-year primary patency of the stent-grafts was 82.95%. From discharge to 24 months, 14 (16%) patients developed thromboses of one of the endograft’s limbs. Of these, 13 patients underwent hybrid surgery to relieve extremity ischemia. The procedures consisted in repeat exposure of the CFA on the side of the lesion, recanalization of the thrombosed stent-graft limb with hydrophilic and super stiff guidewires, then thrombectomy of fresh thrombotic masses with a balloon catheter through the preliminary inserted guidewire, followed by either stenting of residual stenoses or occlusion with nitinol stents. Portions of lesion in the endograft limb were stented with Wallstent Uni (Boston Scientific) stents 1–2 cm smaller in diameter than the previously implanted stent graft. Stenoses of the outflow arteries were removed by implantation of nitinol self-expanding stents Absolut Pro (Abbott). One patient after failed attempts of endograft limb recanalization was subjected to femorofemoral crossover bypass.
For type I endoleaks persisting over a period from 8 to 18 months, additional interventions were performed: implantation of the endograft extension into the proximal landing zone – in 2 patients, and additional stent-graft limb into the distal landing zone – in 2 patients. A further two patients with type Ia endoleak and progressing dilatation of the proximal aneurysmal neck were found to have sac growth by more than 2 cm. Due to impossibility of endovascular sealing of the leak zone, open operations were performed: aneurysmectomy, aortobifemoral prosthetic repair. Both interventions proved uneventful, with no complications. Stenting of the RA was performed in 2 patients for hemodynamically significant stenoses revealed. A total of 22 (25%) repeat operations were performed.
The survival rate amounted to 96.59%. One patient died from the novel coronavirus infection, another one – from ruptured aneurysm within 2 years after primary endoprosthetic repair.
Risk factors for the development of stent-graft limb thrombosis were assessed by means of the univariate Cox regression analysis demonstrating that the presence of parietal thrombotic masses in the area of the proximal neck increased the risk of developing stent-graft limb thrombosis in the postoperative period [RR 5.03 (1.28; 19.81), p=0.02]. The data are shown in Table 3.
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It was found that the presence of angulation of the proximal aneurysmal neck increased the risk of the development of endoleaks [RR 1.55 (1.06; 5.30), p=0.04] (Table 4).
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Discussion
Endovascular treatment of abdominal aortic aneurysms is a safe alternative to open operation. Thus, in their systematic review H. Alsusa et al. demonstrated a statistically significant decrease in perioperative mortality after endovascular aneurysm repair than after open surgical repair. Stenting of abdominal aortic aneurysm yielded better long-term results, with the difference hovering on the brink of statistical significance [5].
However, despite this, one of the problems in endovascular treatment of abdominal aortic aneurysms is unfavorable anatomy of the aortic aneurysm proximal neck (wide and short, conical or strongly curved, the presence of thrombus, aortic wall calcinosis). Endoprosthetic repair of aneurysms with such a proximal neck is associated with an increased risk of endoleak occurrence. In the study conducted by N.A. Al-Zoubi et al., including a total of 43 patients, the incidence of endoleaks amounted to 21%, with type Ia endoleaks accounting for 2.3%, type Ib endoleaks for 4.7%, and the most frequent type II endoleak for 14%. There were no type III, IV and V endoleaks in either early or long-term follow-up periods [6]. According to the results of our study, endoleaks during the in-hospital period accounted for 23% and in the remote period of follow-up for 27%, which is consistent with the literature data.
Analyzing our findings showed that the presence of proximal neck angulation over 60° resulted in a 1.55-fold increase in the risk for endoleak development in the mid-term postoperative period, with similar results published previously. Thus, in their study, Albertini J.N. et al. reported that proximal neck angulation was significantly greater in patients who had type Ia endoleaks (50±16, p=0.0005) or graft migration (54±20, p=0.003), compared to patients who had none of these two complications (37±18). Neck diameter was significantly greater in patients with type Ia endoleaks (p=0.05). The presence of a conical shape, thrombosis and calcification was also associated with a risk of type I endoleaks and graft migration [7].
Mention should be made that in our study there was no stent-graft migration in patients with proximal aneurysmal neck angulation above 60°. Apparently, it may be attributed to more meticulous calculation of the sizes of the implanted device and the use of new more elastic frames of modern endografts. This can be confirmed by the study of C. Mascoli et al., who analyzed their experience with the Gore Excluder endografts with active control system in abdominal aortic aneurysms with severe infrarenal neck angulation (the median neck angle 70°). Technical success was achieved in all cases, with perioperative type-I/III and II endoleaks observed in 0 and 4 (16%) patients, respectively, and estimated survival at 24 months amounting to 92% [8].
To solve the problem concerning endoleak development, Y. Chen et al. proposed to fulfill the aneurysmal sac with fibrin glue to prevent type IA endoleak following EVAR. After discharge, the average maximal aneurysm diameter was significantly smaller than before surgery. The postoperative maximal aneurysm diameter decreased in 76 patients and was stable in 22 patients. One patient with aneurysm dilatation was switched to open operation for type IV endoleak. Another patient who had no blood flow to the aneurysmal sac was under close observation, periodically undergoing computed tomography. In the perioperative period and during follow-up there were no recurrence of type I endoleak, distal embolization, migration, bending or dysfunction of the tent graft [9].
Amongst systemic complications occurring after endovascular repair of abdominal aorta aneurysm, of importance are ischemic events of adjacent vascular basins. Their development may be caused by thrombosis and thromboembolisms of arteries, dissection of aneurysmal wall, resulting from incorrect position of the sent graft or during its implantation. Thus, in their study D. Daye et al. reported that ischemic complications after endovascular abdominal aortic aneurysm repair were present in 9% of patients. The most common complication was lower extremity ischemia [10]. We noted that a predictive factor of dysfunction of the stent graft itself and the development of ischemic complications is the presence of thrombotic masses in the area of the proximal aneurysmal neck.
Postoperative renal ischemia may develop due to thromboembolism or resulting from unintentional cover of the RA ostium with the endograft in a short neck. In our study 2 patients in the remote period required RA stenting.
M.T. de Bruijn et al. described 5 clinical case reports of endovascular treatment of complicated abdominal aortic aneurysms by combining various types of endografts. They concluded that combining the AFX and Valiant Captiva endografts is an off-the-shelf solution for treatment of large diameter aortic necks and small aortic bifurcations [11]. R. Giudice et al. presented their experience with EndoAnchors in difficult anatomies of aneurysms, concluding that EndoAnchors can be safely used in the prevention and treatment of type Ia endoleaks in patients with challenging aortic necks, with good results in terms of sac exclusion and diameter reduction in the mid-term follow-up [12].
In our study, technical success of the operation was achieved in 98.8% of patients. The 2-year primary patency of the stent-grafts was 82.95%.
Conclusion
Endoprosthetic repair of abdominal aortic aneurysms with unfavorable anatomy of the proximal landing zone is a safe and effective method of treatment, with a technical success rate of 98.8%.
It was found that angulation in the area of the aneurysmal neck increases the risk of the development of endoleaks in the mid-term follow-up period, and the presence of thrombotic masses in the area of the aneurysmal neck is a predictive factor for thrombosis of the stent-graft limbs.
High risk of complications in the remote period of follow-up suggests the necessity of meticulous postoperative instrumental control of the results of operation in this patient cohort.
Study limitations. There are of course limitations of this study. First, it was a retrospective study without a control group for comparison. Second, the procedures of endovascular abdominal aortic aneurysm repair were performed using various stent grafts of several manufacturers and hence with different recommended constraints of the proximal landing zone.
References
1. Antoniou G.A., Antoniou S.A., Torella F. 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. European Journal of Vascular and Endovascular Surgery. 2020; 59 (3): 385–397. DOI: https://doi.org/10.1016/j.ejvs.2019.11.030
2. Chaikof E.L., Dalman R.L., Eskandari M.K., et al. The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. Journal of Vascular Surgery. 2018; 67 (1): 2–77.e2. DOI: https://doi.org/10.1016/j.jvs.2017.10.044
3. Kyriakou F., Dempster W., Nash D. Analysing The Cross-Section of The Abdominal Aortic Aneurysm Neck and Its Effects on Stent Deployment. Scientific Reports. 2020; 10: 4673. DOI: https://doi.org/10.1038/s41598-020-61578-y
4. Popova I.V., Ignatenko P.V., Rabtsun A.A., et al. Outcomes of endoprosthetic repair of abdominal aortic aneurysm. Angiology and Vascular Surgery. 2021; 27 (4): 59–69. DOI: https://doi.org/10.33529/ANGIO2021402 (in Russian)
5. Alsusa H., Shahid A., Antoniou G.A. A comparison of endovascular versus open repair for ruptured abdominal aortic aneurysm – Meta-analysis of propensity score-matched data. Vascular. 2022; 30 (4): 628–638. DOI: https://doi.org/10.1177/17085381211025168
6. Al-Zoubi N.A., Al-Shawwa Z. Complications of endo-vascular aortic repair for abdominal aortic aneurysm: A retrospective single-centre experience. Annals of Medicine and Surgery. 2021; 23 (64): 102219. DOI: https://doi.org/10.1016/j.amsu.2021.102219
7. Albertini J.N., Kalliafas S., Travis S., et al. Anatomical risk factors for proximal perigraft endoleak and graft migration following endovascular repair of abdominal aortic aneurysms. European Journal of Vascular and Endovascular Surgery. 2000; 19 (3): 308–312. DOI: https://doi.org/10.1053/ejvs.1999.1045
8. Mascoli C., Faggioli G., Goretti M., et al. Endovascular Treatment of Abdominal Aortic Aneurysm With Severe Angulation of Infrarenal Aortic Neck by Gore Conformable Endograft. Journal of Endovascular Therapy. 2023; 30 (3): 410–418. DOI: https://doi.org/10.1177/15266028221083461
9. Chen Y., Zhang L., Liu Z., et al. Fibrin Glue Sac Filling for Preventing Type II Endoleak, Short-Term Outcomes of a Prospective Randomized Controlled Trial. Journal of Endovascular Therapy. 2023; 21: 15266028231159245. DOI: https://doi.org/10.1177/15266028231159245
10. Daye D., Walker T.G. Complications of endovascular aneurysm repair of the thoracic and abdominal aorta: evaluation and management. Cardiovascular Diagnosis and Therapy. 2018; 8 (Suppl 1): S138–S156. DOI: https://doi.org/10.21037/cdt.2017.09.17
11. de Bruijn M.T., Tournoij E., van den Heuvel D.A., et al. Endovascular treatment of complex abdominal aortic aneurysms by combining different types of endoprostheses. Vascular. 2016; 24 (4): 425–429. DOI: https://doi.org/10.1177/1708538116652763
12. Giudice R., Borghese O., Sbenaglia G., et al. The use of EndoAnchors in endovascular repair of abdominal aortic aneurysms with challenging proximal neck: Single-centre experience. JRSM Cardiovascular Disease. 2019; 8: 2048004019845508. DOI: https://doi.org/10.1177/2048004019845508
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