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Corresponding author. Department of Vascular and Endovascular Surgery, Paracelsus Medical University, Klinikum Nürnberg, Breslauer Strasse 201, 90471, Nürnberg, Germany.
Affiliations
Department of Vascular and Endovascular Surgery, Paracelsus Medical University, Nuremberg, Germany
The use of fenestrated stent grafts to treat short neck, juxta- and suprarenal aortic aneurysms is increasing worldwide, but midterm outcome reports are scarce. This study aimed to report peri-operative results and midterm outcomes after five years from a single centre.
Methods
Patients treated with primary fenestrated endovascular aortic aneurysm repair (FEVAR) for short neck, juxta- or suprarenal aortic aneurysms within the period January 2010 to May 2020 with follow up in the centre were included. Early (technical success, operative mortality, spinal cord ischaemia) and five year outcomes (cumulative survival, freedom from aortic related death, target vessel patency, target vessel instability [TVI], re-interventions) were analysed.
Results
A total of 349 patients (313 male, mean age 72.3 ± 7.7 years) were included in the study. Technical success was 98% (342/349). The thirty day mortality rate was 0.9% (3/349). Estimated survival at five years was 69.3 ± 3.1%. Freedom from aneurysm related death at five years was 98.8% ± 0.7%. Estimated target vessel patency at five years was 98.7 ± 0.4%. Estimated freedom from TVI at five years was 97.2 ± 0.6%. Estimated freedom from re-intervention at five years was 86.5 ± 2.3%. Survival did not differ significantly between patients with and without re-interventions (p = .088).
Conclusion
Midterm results of FEVAR remain good as indicated by sustained target vessel patency and low aortic related mortality rates. An important proportion of patients require re-interventions, which do not have a negative impact on midterm survival.
Fenestrated endovascular aortic aneurysm repair (FEVAR) is being used increasingly to treat complex abdominal aortic aneurysms. Several specialised centres have shown very good short term outcomes with high technical success and low peri-operative mortality and morbidity rates. Midterm outcomes of FEVAR are less well studied. This study shows that midterm outcomes of FEVAR remain good with low aortic related mortality rates and sustained target vessel patency. Late re-interventions are required for a substantial proportion of patients, but this does not affect survival during follow up.
Introduction
Fenestrated endovascular aneurysm repair (FEVAR) was first reported in 1999 for the treatment of a juxtarenal aortic aneurysm.
The technique has evolved over time and the number of the included target vessels and fenestrations has been increasing in expert centres aiming to treat more complex pathologies and to create a longer proximal sealing zone.
Comparison of outcomes for double fenestrated endovascular aneurysm repair versus triple or quadruple fenestrated endovascular aneurysm repair in the treatment of complex abdominal aortic aneurysms.
FEVAR was initially developed to treat high risk patients unfit for open surgery and anatomically unsuitable for standard EVAR. Gradually, FEVAR became an alternative option to treat patients suitable for open repair. In some institutions, FEVAR has gradually evolved to be the first line treatment for anatomically suitable short neck, juxta- and suprarenal aortic aneurysms.
The European Society for Vascular Surgery abdominal aortic aneurysm (AAA) guidelines of 2019 state that for juxtarenal aortic aneurysms, FEVAR should be considered the preferred treatment option in those with suitable anatomy.
Editor's Choice – European Society for Vascular Surgery (ESVS) 2019 clinical practice guidelines on the management of abdominal aorto-iliac artery aneurysms.
Most publications on FEVAR focus on early outcomes. Several specialised centres have shown very good technical success rates with low peri-operative mortality and morbidity.
Editor’s Choice – Fenestrated or branched endovascular versus open repair for complex aortic aneurysms: meta-analysis of time to event propensity score matched data.
, but also need to be taken into account when balancing the different treatment options.
This report presents peri-operative and midterm outcomes of FEVAR for short neck, juxta- or suprarenal aortic aneurysms with the goal to determine FEVAR durability and risk of late failure. Data from patients treated in a single centre institution over a ten year period were analysed.
Materials and Methods
Patients treated with FEVAR for short neck, juxta- or suprarenal aortic aneurysm within the period January 2010 to May 2020 and who were followed in the institution were analysed for this study. Patients treated in the institution, but followed by their referring vascular centre, (frequently far away or even in a foreign country), were excluded from the study. Patients that had previously undergone one or more open or endovascular aortic procedures were also excluded. Patients with a thoraco-abdominal aortic aneurysm were excluded even if treated with 4× FEVAR (Fig. 1)
Figure 1Flowchart of included patients treated with primary fenestrated endovascular aneurysm repair (FEVAR) for short neck, juxta- or suprarenal aortic aneurysm within the period January 2010 to May 2020. BEVAR = branched endovascular aneurysm repair; AAA = abdominal aortic aneurysm.
All patients signed informed consent for collection, processing, and review of clinical and morphological data. Ethics committee approval was waived in view of the design of the study with anonymised retrospective data analysis.
The main indication for FEVAR included a proximal infrarenal neck too short for standard EVAR, but otherwise suitable anatomy for EVAR in an AAA of at least 50 mm diameter or in a smaller AAA in conjunction with an iliac aneurysm larger than 35 mm. Details of device design, and procedure execution have been described previously.
Patients were followed with clinical and laboratory examination including abdominal Xrays in standardised anteroposterior and oblique views as reference prior to discharge. Computed tomography angiography (CTA) scans were usually performed at one month, one year, and thereafter, depending on each patient’s characteristics. On suspicion of endoleak or target vessel malperfusion, additional digital subtraction angiography for further evaluation and possible re-intervention was carried out. For non-suspicious cases, follow up with abdominal Xray, duplex ultrasonography, and renal function was performed, with the need for yearly CTA being discussed within the group with the aim of reducing their number.
Data analysis
Statistical analysis was performed using SPSS, version 26.0 (IBM Corp, Armonk, NY). Variables are presented as mean ± standard deviation (SD). Early analysed outcomes included technical success, 30 day mortality and peri-operative spinal cord ischaemia (SCI) rates. Technical success was defined as successful deployment of the planned stent grafts with patent stented target vessels and absence of type I or III endoleak in the first post-operative CTA. Midterm durability endpoints included survival, freedom from aneurysm related death, target vessel patency, target vessel instability (TVI), and freedom from re-interventions. Aneurysm related death included all peri-operative deaths within 30 days of the procedure and all subsequent deaths during follow up associated with complications of the aortic repair. TVI was defined as a composite endpoint of target vessel occlusion, or re-intervention indicated to treat a target vessel related complication, or any death or rupture related to target vessel complication.
Time dependent outcomes were reported using Kaplan–Meier estimates, and differences were determined by the log rank test. A p value less than .05 was considered statistically significant.
Results
Patient and aneurysm characteristics
During the study period, 349 patients (313 male, mean age 72.3 ± 7.7 years) were included in the study (Fig. 1). Patient comorbidities and risk factors are listed in Table 1. The mean aneurysm diameter was 59.3 ± 8.4 mm and mean proximal infrarenal neck length 1.3 ± 2.1 mm. Forty-seven (13.5%) patients had a short neck AAA, 240 (68.8%) a juxtarenal AAA, and 62 (17.8%) a suprarenal AAA. Three (0.9%) patients had an acute aneurysm (contained rupture: n = 2, symptomatic: n = 1). In two of these patients, FEVAR had previously been planned and the stent graft was readily available. In the third patient, a stent graft delivered for another patient was used. The stent graft was immediately re-ordered and became available in due time for the initial patient.
Table 1Pre-operative characteristics of 349 patients treated with primary fenestrated endovascular aneurysm repair for short neck, juxta- or suprarenal aortic aneurysms
Variable
Patients (n = 349)
Smoking, current or past
180 (51.6)
Hypertension
287 (82.2)
Diabetes mellitus
61 (17.5)
Hypercholesterolaemia
154 (44.1)
CAD
225 (64.5)
COPD
143 (41.0)
Serum creatinine >100 μmol/L
138 (39.5)
PAD
87 (24.9)
ASA ≥III
154 (44.1)
Data are shown as n (%). CAD = coronary artery disease; PAD = peripheral arterial disease; COPD = chronic obstructive pulmonary disease; ASA = American Society of Anesthesiologists.
Stent grafts were customised based on the Cook Zenith system (William A. Cook Australia, Ltd, Brisbane, Australia) fitting fenestrations and scallops for the visceral vessels according to pre-operative CTA measurements. Most commonly, a composite three part system was used consisting of a proximal fenestrated tube, a distal bifurcated component, and a contralateral limb.
A stent graft with fenestrations for the renal arteries only (and most commonly a scallop for the superior mesenteric artery, SMA) was used in 132 (37.8%) patients. A stent graft with fenestrations for the renal arteries and the SMA (and most commonly a scallop for the coeliac trunk) was used in 172 (49.3%) patients. A stent graft with four fenestrations for the renal arteries, SMA, and coeliac trunk was used in 45 (12.9%) patients. Stent graft design evolved during the study period towards a more complex configuration.
Comparison of outcomes for double fenestrated endovascular aneurysm repair versus triple or quadruple fenestrated endovascular aneurysm repair in the treatment of complex abdominal aortic aneurysms.
The mean sealing zone length (excluding the length of the scallop) increased from 22.2 ± 7 mm in 2010 to 45.3 ± 14 mm in 2019.
A total of 1 223 vessels were targeted (935 fenestrations, 288 scallops), including 669 renal arteries, 337 SMAs, and 217 coeliac trunks. Of those, 922 were stented with a bridging stent graft. Bridging stent graft types used were the Advanta V12 (Atrium Medical; Hudson, NH, USA) in 824 target vessels, the BeGraft peripheral (Bentley InnoMed GmbH, Hechingen, Germany) in 45 target vessels, and the Lifestream (Bard Peripheral Vascular, Tempe, AZ, USA) in 53 target vessels.
Technical success
Technical success was achieved in 342 (98%) patients. Technical failure occurred in seven patients. In five patients, technical failure concerned a target vessel (renal artery) problem (unsuccessful catheterisation or stenting or dissection). One patient had to be converted intra-operatively due to rupture of a calcified iliac artery after stent graft introduction and partial deployment. One patient died intra-operatively due to myocardial infarction after a complicated procedure in a “shaggy” aorta with embolisation problems.
Peri-operative outcomes
The thirty day mortality rate was 0.9% (3/349). One patient died intra-operatively, as mentioned above. One patient died of complications following post-operative renal bleeding. One patient with severe chronic obstructive pulmonary disease died of respiratory complications after re-intubation.
Peri-operative SCI complications occurred in two (0.6%) patients. One patient (4× FEVAR starting 3 cm above the coeliac trunk) developed paraplegia on day four post-operatively that improved to paraparesis after cerebrospinal fluid drainage. A second patient (3× FEVAR with double width scallop for the coeliac trunk) presented with lower limb and pelvic hypo-aesthesia (without motor deficit) on the third post-operative day. Symptoms improved quickly after cerebrospinal fluid drainage and at one month he had recovered completely.
Midterm outcomes
During follow up, 18 (5.2%) patients were lost to follow up at some stage, mainly due to old age and or comorbidity. Mean follow up duration was 49.3 ± 32.2 months (range 1 – 127 months). The survival curve is shown in Fig. 2A. Estimated survival at five years was 69.3 ± 3.1%. Freedom from aneurysm related death at five years was 98.8 ± 0.7% (Fig. 2B). In total, seven patients died due to aneurysm related causes. Three patients died peri-operatively and are described above. One patient died of mesenteric ischaemia due to superior mesenteric artery occlusion 27 months after the procedure. One patient died of an aortoduodenal fistula following open conversion for rupture twice (one laparotomy with lumbar artery ligation and preservation of the graft, a second laparotomy with complete graft removal and aortobifemoral graft) 36 months after the initial procedure. One patient died of rupture probably related to a type II endoleak 66 months after the procedure. This patient had presented with aneurysm sac growth (61 – 68 mm) during follow up. A selective angiogram showed a type II endoleak without signs of type I/III endoleak and a conservative approach was chosen. The last patient also died of rupture 80 months after the procedure. Three months before rupture he had undergone a native computed tomography scan (without contrast due to renal insufficiency) that demonstrated good proximal and distal stent graft apposition and no aneurysm growth.
Figure 2Cumulative Kaplan–Meier estimate of the cumulative overall patient survival (A), and freedom from aneurysm related mortality (B) in 349 patients treated with primary fenestrated endovascular aneurysm repair for short neck, juxta- or suprarenal aortic aneurysms.
During follow up, occlusion was documented in 14 target vessels including 12 renal arteries (in 11 patients) and two SMAs. One SMA occlusion was noted in a single width scallop and one in a large strut free stented fenestration. Renal artery occlusion resulted in permanent dialysis in one patient (bilateral renal occlusion). No other patient needed dialysis during the follow up period. SMA occlusion was lethal in one patient as described before. In four patients, a potential reason for target vessel occlusion was identified (stopped antiplatelets due to other procedure: n = 3, severe dehydration due to gastroenteritis: n = 1). Occlusion rates according to bridging stent graft type were 8/824 (1%) for the Advanta V12, 1/45 (2.2%) for the BeGraft peripheral, and 1/53 (1.9%) for the Lifestream. The remaining occlusions were noted in non-stented vessels. Estimated target vessel patency at five years was 98.7 ± 0.4% (Fig. 3A). Estimated freedom from TVI at five years was 97.2 ± 0.6% (Fig 3B).
Figure 3Estimated target vessel patency (A), and freedom from target vessel instability (B) in 349 patients treated with primary fenestrated endovascular aneurysm repair for short neck, juxta- or suprarenal aortic aneurysms.
A total of 47 re-interventions were performed in 38 (10.9%) patients during follow up (Table 2). Estimated freedom from re-intervention at five years was 86.5 ± 2.3% (Fig. 4). Τhe most common type of re-intervention was a relining or extension of a target vessel bridging stent graft. Proximal stent graft extension was required in three (0.9%) patients, in two of them to treat a type Ia endoleak (with a second fenestrated branched stent graft) and in one patient to treat an aortic wall haematoma dissection (with thoracic tube stent graft). Estimated survival did not differ significantly between patients with and without re-intervention (p = .088) (Fig. 5).
Table 2Re-interventions during follow up in 349 patients treated with primary fenestrated endovascular aneurysm repair for short neck, juxta- or suprarenal aortic aneurysms
Re-intervention
n
Time of re-intervention – mo
Target vessel bridging stent relining or extension
14
1, 2, 3, 5, 9, 13, 18, 19, 19, 20, 25, 25, 32, 44
Distal stent graft extension (type Ib endoleak)
9
24, 44, 49, 52, 53, 57, 73, 77, 86
Coil embolisation (type II endoleak)
8
7, 9, 12, 12, 14, 18, 20, 21
Iliac PTA or stenting
5
1, 1, 14, 25, 48
Proximal stent graft extension (type Ia endoleak: 2; Dissection: 1)
Figure 4Estimated freedom from in 349 patients treated with primary fenestrated endovascular aneurysm repair for short neck, juxta- or suprarenal aortic aneurysms
Figure 5Estimated survival in in 349 patients treated with primary fenestrated endovascular aneurysm repair for short neck, juxta- or suprarenal aortic aneurysms with and without re-intervention
Several centres including this institution have published early outcomes of FEVAR, demonstrating high initial technical success rates and early safety and efficacy of the technique.
The present study reports the FEVAR experience over a 10 year period for short neck, juxta- and suprarenal AAA aiming to provide data with regard to midterm FEVAR durability.
Estimated survival at five years was 69.3%, demonstrating that a significant proportion of treated patients survive the procedure. Aneurysm related mortality, including both peri-operative and late deaths, remained low, showing that FEVAR is an effective treatment in preventing aneurysm rupture in the vast majority of the patients. Apart from the patients that died peri-operatively, a total of four patients died of aneurysm related causes during follow up including one patient who died of mesenteric ischaemia and three patients who died of aneurysm rupture complications.
Target vessel patency remained excellent during the follow up period, as also previously documented in other series.
Midterm outcomes of a prospective, nonrandomized study to evaluate endovascular repair of complex aortic aneurysms using fenestrated-branched endografts.
Freedom from TVI remained above 97% at five years. A life threatening target vessel occlusion of the SMA was rare, with two events noted in 349 patients. Previous studies have shown that unstented SMA scallops, especially the old single width design (10 mm), may be more prone to occlusion due to a “shuttering” effect.
The low event rate in this series prevents any meaningful statistical comparison between scallops and stented fenestrations for the SMA. Besides, such a comparison has limited clinical relevance nowadays given that a scallop for the SMA has been practically abandoned in many centres in favour of a large fenestration as part of a 3×/4× FEVAR procedure. All other occluded target vessels were renal arteries. Only one patient required permanent dialysis due to bilateral renal artery occlusion. Mean time to target vessel occlusion was 16.7 months with 71% of the occlusions noted within the first 18 months after the procedure. This shows that a target vessel occlusion is most likely to occur early after the initial procedure. Similar findings were also reported recently by Sveinsson et al. who showed that 73% of target vessel occlusions occurred within the first year of follow up.
The authors suggested that this may be due to an initial settling distal migration of the aortic stent graft or technical imperfections missed in the intra-operative or early post-operative imaging. In three patients, the potential reason that led to target vessel occlusion was the pause in antiplatelet therapy, which most commonly includes aspirin and clopidogrel for at least three months and preferentially for six and then monotherapy with aspirin.
More than 70% of re-interventions were performed to correct a target vessel problem, loss of distal stent graft sealing, or a type II endoleak. Proximal sealing problems were noted in less than 1%, showing that FEVAR may provide durable proximal sealing in the majority of the patients.
Another important point is the impact of re-interventions on the midterm mortality rate of patients after FEVAR. The data show that although an important proportion of patients will require re-intervention after FEVAR, these secondary procedures do not negatively affect survival during follow up. This is in line with the findings of other groups; Giles et al. reported re-intervention data after F/BEVAR on 308 patients and also showed that re-interventions do not negatively affect survival during follow up.
Zetterval et al. reported re-intervention outcomes from 1 681 patients of the US Fenestrated and Branched Aortic Research Consortium with a mean follow up of 23 months. Re-interventions were associated with improved late survival, implying that some re-interventions may have been life saving.
In view of the above data, the treating physicians should clearly inform FEVAR patients about the need for close surveillance and the probability of secondary procedures (mostly not life threatening) to secure durability of the repair.
Peri-operative outcomes were very good, with technical success and 30 day mortality rates similar to standard EVAR. This can be attributed to the high volume of cases that has made FEVAR a standard routine procedure for the involved team over the years. Additionally, the treated patient cohort included both high risk patients, but also a proportion of lower risk patients that could have undergone open surgery.
The single centre retrospective nature of the study is associated with several limitations. Practice changed over time with the use of triple and quadruple fenestrated grafts for the same extent of disease. Five per cent of the patients were lost to follow up, mostly due to advanced age and extensive comorbidity. The risk of missing some events must be acknowledged. Both the local population and the patients referred were a mixed group of low and high risk patients. Referral from other centres occurred for different reasons, both surgeon and patient related. Finally, this series originates from a high volume academic centre with large experience in complex aortic endovascular repair, and the presented outcomes may not be reproducible in lower volume settings.
Conclusions
This series shows that midterm outcomes of FEVAR for short neck, juxta- and suprarenal aneurysms remain good with sustained patency of target vessels and a low aortic related mortality rate. There is a need for re-intervention in a substantial proportion of patients, but this does not affect the survival during follow up.
Conflict of Interest
Eric L.G. Verhoeven has received educational grants and is a consultant for Cook Inc., W.L. Gore & Associates, Siemens, Atrium-Maquet, and Bentley Innomed. Athanasios Katsargyris has received speaker fees from Cook Inc., & W.L. Gore & Associates, and is a consultant for Bentley Innomed.
Comparison of outcomes for double fenestrated endovascular aneurysm repair versus triple or quadruple fenestrated endovascular aneurysm repair in the treatment of complex abdominal aortic aneurysms.
Editor's Choice – European Society for Vascular Surgery (ESVS) 2019 clinical practice guidelines on the management of abdominal aorto-iliac artery aneurysms.
Editor’s Choice – Fenestrated or branched endovascular versus open repair for complex aortic aneurysms: meta-analysis of time to event propensity score matched data.
Midterm outcomes of a prospective, nonrandomized study to evaluate endovascular repair of complex aortic aneurysms using fenestrated-branched endografts.
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