Endovascular aneurysm repair: prevention and treatment of complications
Goudeketting, Seline
DOI:
10.33612/diss.98524202
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2019
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Goudeketting, S. (2019). Endovascular aneurysm repair: prevention and treatment of complications.
Rijksuniversiteit Groningen. https://doi.org/10.33612/diss.98524202
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Midterm Single-Centre Results
of Endovascular Abdominal
Aortic Aneurysm Repair with
Additional EndoAnchors
J Endovasc Ther. 2018 Dec;24(1):90-100
Seline R. Goudeketting Jan Wille Daniel A.F. van den Heuvel Jan-Albert Vos Jean-Paul P.M. de Vries
8
ABSTRACT
Purpose: To review midterm clinical outcomes of EndoAnchor placement during or after endovascular aneurysm repair (EVAR) or chimney EVAR (ch-EVAR).
Materials and Methods: A retrospective analysis was conducted of 51 consecutive patients [median age 75 years; 38 men] who underwent EVAR/ch-EVAR with EndoAnchor placement between June 2010 and December 2016 to prevent seal failures (31, 61%) or to treat type IA endoleak and/or migration (20, 39%). Median aortic neck diameter was 27.7 mm and median neck length was 9.0 mm. Thirty-three (65%) had a conical neck; 48 (94%) had at least 1 hostile neck characteristic. Thirty-two (63%) patients had severe comorbidities (ASA score ≥III). Eight patients had a single ch-EVAR procedure. Baseline patient characteristics, anatomic variables, procedure details, early and late complications, reinterventions, and aneurysm-related and all-cause mortality rates were recorded. Follow-up imaging was performed with computed tomography angiography (CTA) or duplex ultrasonography.
Results: Median procedure time was 100 minutes; a median of 6 EndoAnchors were implanted. There were 10 (10%) residual type IA endoleaks at the end of the procedure; 9 had resolved by the first postoperative CTA. One residual and 2 new type IA endoleaks were identified at the first postoperative imaging. Median follow-up for the entire cohort was 24.0 months, during which 3 new type IA endoleaks were identified. Five of the 6 type IA endoleaks were treated, 1 resolved spontaneously. There was 1 endograft limb occlusion without clinical consequences, 1 chimney graft occlusion without possibilities for a reintervention, 1 rupture after type IV endoleak (a Nellix device was successfully deployed within the main device), and 1 complete graft explantation for infection. There was no new-onset hemodialysis. Kaplan-Meier estimates of freedom from type IA endoleak, proximal neck–related reinterventions, and aneurysm-related mortality at 2 years were 87.3%, 92.2%, and 94.0%, respectively.
Conclusion: EndoAnchors are helpful in the endovascular treatment of unfavorable proximal aortic necks, with fair midterm results.
INTRODUCTION
Endovascular aneurysm repair (EVAR) is an effective treatment for the exclusion of abdominal aortic aneurysms (AAAs). To assess complications during follow-up, both the Society for Vascular Surgery and the European Society for Vascular Surgery recommend that follow-up imaging should include a computed tomography (CT) scan at 1 and 12 months postoperatively, which can thereafter be replaced by duplex ultrasound if no complications are seen during the first postoperative year.1,2 After EVAR, especially in patients with challenging aortic neck anatomy, type Ia endoleaks and endograft migration due to insufficient sealing or fixation are lingering challenges.3 The Heli-FX EndoAnchor System (Medtronic Vascular, Santa Rosa, CA, USA) was designed to increase the migration resistance of abdominal aortic endografts and prevent proximal neck complications, which has been previously demonstrated and described in experimental settings4,5 and feasibility studies with small patient cohorts.6-8 Implantation of EndoAnchors has been reported to be useful in the prevention of migration and type Ia endoleaks or in the treatment of such complications.6,9-12 The risk for proximal neck–related complications increases with longer follow-up.3 Small patient series on the use of EndoAnchors after EVAR have been reported.6-8 The Aneurysm Treatment Using the Heli-FX Aortic Securement System Global Registry (ANCHOR) was designed to assess worldwide use of EndoAnchors in patients with unfavorable aortic neck anatomy.9,10,13,14 Moreover, EndoAnchors in combination with chimney EVAR (ch-EVAR) procedures have been described only sporadically.15,16 Currently, mid- and long-term outcomes after EndoAnchor use is limited to the results from the ANCHOR multicenter registry.9-11,13 Therefore, this study assesses the 2-year clinical outcomes of patients treated with EndoAnchors after EVAR and ch-EVAR in a single high-volume center.
MATERIALS AND METHODS
Study design
A retrospective observational cohort study was undertaken of patients who underwent a primary or revision EVAR or ch-EVAR procedure with additional EndoAnchors (Medtronic Vascular, Santa Rosa, CA, USA) at our institution. The institutional review board approved this study (registration number: Z17.077); because of its retrospective design, individual patient informed consent for data analysis was waived.
All consecutive patients treated with EndoAnchors were identified and electronic medical records were reviewed. Patients were excluded from this cohort if they (1)
were included in the global ANCHOR study, (2) had postoperative follow-up at another hospital so data on possible complications and reinterventions might be unreliable or unknown, or (3) had EndoAnchors used distally to affix the endograft to a challenging iliac landing zone. Patients were divided into 2 groups based on the indication for EndoAnchor use: prophylactic to increase the migration resistance and prevent type IA endoleaks (i.e., prevent proximal neck complications) or therapeutic to treat acute type Ia endoleaks during the primary EVAR or to treat type Ia endoleaks and/or endograft migration during EVAR follow-up.
Patient data collected from individual electronic medical records included baseline demographics (gender, age, comorbidities, and prior AAA surgery) and the American Society of Anesthesiologists (ASA) classification to identify the operative risk per patient. Anatomic characteristics were acquired from the preoperative computed tomography angiography (CTA) scans processed on a 3Mensio vascular workstation (version 9.0; Pie Medical Imaging BV, Maastricht, the Netherlands). The anatomic characteristics measured included AAA diameter, infrarenal neck diameter and length, suprarenal and infrarenal angulation, and thrombus and calcium circumference and thickness. The characteristics of a hostile neck were defined as commonly employed in the literature (i.e., neck length <10 mm, neck diameter >28 mm, infrarenal neck angulation >60°, significant mural thrombus/calcium >2 mm in average thickness or >50% of the aortic wall circumference, or a conical neck).17 A conical neck was defined as a >10% decrease or increase in diameter at 15 mm below the baseline (lowest renal artery), corresponding to a tapered or conical neck, respectively.18 The distribution of EndoAnchors was quantified by counting how many quadrants of the aortic circumference contained EndoAnchors.
Procedure and follow-up
The baseline procedure referred to the one during which EndoAnchors were deployed. Procedure details retrieved from electronic medical records included procedure time, estimated blood loss, type of endograft, and number of EndoAnchors. Procedure success was defined as successful deployment of the endograft and the EndoAnchors without a type IA or III endoleak at completion angiography.19
The use of adjunctive devices or need for adjunct procedures during the EndoAnchor procedure, length of hospitalization, and intensive care admission were documented. Thirty-day and late complications, aneurysm-related and all-cause mortality, as well as reinterventions were recorded. Aneurysm-related mortality included all causes of death within 30 days of the baseline procedure or death at a later time because of aneurysm rupture, reintervention, or surgical conversion. Major nonfatal complications in this cohort were defined as type Ia and Ib endoleaks, type III endoleaks, stent occlusions, aneurysm rupture, and endograft explantation.
Follow-up imaging after the baseline procedure consisted of CTA, magnetic resonance angiography (MRA), and duplex or contrast-enhanced ultrasound. CTA was the preferred imaging modality during the first postoperative year. Follow-up was performed within 60 days after the EndoAnchor procedure, at 1 year, and yearly thereafter. If there were no complications at the 1-year CTA, follow-up was continued with duplex, which was also performed in patients with renal failure (estimated glomerular filtration rate <30 mL/min or serum creatinine >1.2 mg/dL). Follow-up imaging reports were assessed for complications, including stent migration (in case of MRA or CTA), endoleaks, and occlusions.
Patient sample
Between June 2010 and July 2017, 82 patients were treated with EndoAnchors at our institution. Thirty-one patients were ineligible for this analysis due to inclusion in the global ANCHOR study (n=22), postoperative follow-up at another hospital (n=2), or EndoAnchor implantation in the iliac arteries (n=7). Of the remaining 51 patients (median age 75 years; 38 men) 31 patients received prophylactic treatment with EndoAnchors vs 20 patients treated therapeutically for endoleak and/or migration. Patient characteristics are shown in Table 8.1 anatomic characteristics in Table 8.2. Thirty-two (63%) patients had severe comorbidities (ASA score ≥III) and 13 patients had undergone previous EVAR (5 in another hospital). Forty-eight (94%) patients had at least 1 hostile neck criterion.
Five different types of endografts were employed in this cohort [Endurant, Talent, and Valiant (Medtronic Vascular, Santa Rosa, CA, USA); Zenith (Cook Medical, Bloomington, IN, USA); and Excluder (W.L. Gore & Associates, Flagstaff, AZ, USA)].
Statistical analysis
Descriptive statistics were used to present the baseline patient characteristics, anatomic variables, procedure details, and outcomes during follow-up. Normality of the data was tested with the Shapiro-Wilk test. Since the majority of the data were not normally distributed, all continuous data are presented as median [interquartile range (IQR)]. Categorical data are presented as number (percentage). Binary logistic regression was performed to identify independent predictors of major complications. Kaplan-Meier survival curves were generated for freedom from type IA endoleak and proximal neck–associated reinterventions, as well as for aneurysm and all-cause mortality; groups were compared with the log-rank test. The estimates are presented with the 95% confidence interval (CI). The threshold of statistical significance was P < .05. Statistical analyses were performed with SPSS (version 24; IBM Corporation, Armonk, NY, USA).
Table 8.1. Baseline patient characteristics.a
Variable Total (n=51) Prophylactic (n=31) Therapeutic (n=20) Age, years 75 (70-78), range 53-88 74 (66-78), range 53-88 76 (72-79), range 57-84 Men 38 (75) 24 (77) 14 (70)
Body mass index, kg/m2 26.2 (23.2-29.0) 26.6 (23.1-29.0) 25.4 (24.1-29.7)
Body mass index >30 kg/m2
7 (14) 3 (10) 4 (20)
Myocardial infarction 17 (33) 14 (45) 3 (15)
Cardiac history 25 (49) 17 (55) 8 (40)
Hypertension 22 (43) 13 (42) 9 (45)
Peripheral artery disease 5 (10) 4 (13) 1 (5)
Stroke/TIA 3 (6) 1 (3) 2 (10)
COPD 12 (24) 6 (19) 6 (30)
Coronary artery disease 6 (12) 1 (3) 5 (25) History of malignancy 13 (26) 6 (19) 7 (35) Diabetes mellitus 8 (16) 5 (16) 3 (15) Smoking history 28 (55) 17 (55) 11 (55) GFR <60 mL/min/1.73m2 12 (24) 5 (16) 7 (35) Serum creatinine >1.2 mg/dL 10 (20) 4 (13) 6 (30)
Previous AAA surgery 13 (26) 1 (3) 12 (60)
ASA class
II 19 (37) 11 (36) 8 (40)
III 31 (61) 19 (61) 12 (60)
IV 1 (2) 1 (3) 0 (0)
Abbreviations: AAA, abdominal aortic aneurysm; ASA, American Society of Anesthesiologists; COPD, chronic obstructive pulmonary disease; GFR, glomerular filtration rate; TIA, transient ischemic attack.
aContinuous data are presented as the median (interquartile range); categorical data are given as the number
(percentage).
RESULTS
Procedure outcomes
Details of the procedures are shown in Table 8.3. Fifty of the 51 procedures were elective; the urgently treated patient was already in our hospital for pneumonia and septicemia when she developed pain in the lower abdomen. CTA showed a ruptured infrarenal AAA of 9.7 cm. The patient collapsed in the trauma unit and was immediately transferred to the operating theatre, where she received an Endurant II endograft and prophylactic EndoAnchors; she is alive at 19 months follow-up.
The Endurant was the most commonly implanted endograft (37, 74%). Single chimney grafts were implanted in 8 patients (5 prophylactic, 3 therapeutic). Two of
the 3 patients with no hostile neck criteria were treated for endoleak and migration, respectively. The third patient underwent a procedure with an iliac branch device (IBD) because of a left common iliac artery aneurysm. Because of the challenging iliac landing zone, the decision was made to prophylactically deploy EndoAnchors to ensure adequate proximal seal and prevent late migration.
A total of 340 EndoAnchors were deployed, with a median of 6 EndoAnchors (IQR 5-7) in the prophylactic cases and a median of 6 (IQR 5, 9) in the therapeutic patients to treat endoleak (14, 70%), migration (5, 25%), or both (1, 5%). There were 37 patients with aortic neck diameters ≤29 mm, with a median of 6 (IQR 5-6) deployed EndoAnchors in the prophylactic group (n=19) vs 7 (IQR 5-9) in the therapeutic group (n=18). One patient of the therapeutic arm had received only 3 EndoAnchors, i.e., less than the recommended number of EndoAnchors according to the instructions for use (IFU). Fourteen patients had neck diameters >29 mm (12 prophylactic and 2 therapeutic). The median number of deployed EndoAnchors in the prophylactic group was 6 (IQR 6-7), with 2 patients receiving less than the recommended 6 EndoAnchors (i.e., 1
Table 8.2. Baseline anatomic characteristics.a
Variable Total (n=51) Prophylactic (n=31) Therapeutic (n=20) Preoperative imaging, d 45.0 (29.0-67.0) 42.0 (25.0-69.0) 51.0 (32.8-63.8) Maximum aneurysm sac diameter, mm 63.7 (57.3-71.0) 62.1 (56.6-68.0) 67.6 (58.4-80.1) Aortic neck diameter, mm
Highest renal artery 26.4 (23.0-30.1) 27.1 (23.0-30.5) 25.1 (23.0-27.5) Baseline (lowest renal artery) 27.7 (24.7-30.8) 28.2 (24.9-31.4) 26.8 (24.0-28.5) 5 mm distal to lowest renal artery 28.7 (25.5-31.7) 29.8 (27.2-32.0) 28.2 (23.5-30.9) 10 mm distal to lowest renal artery 30.8 (28.0-32.9) 31.2 (28.3-33.7) 30.2 (25.2-31.4) 15 mm distal to lowest
renal artery
31.8 (29.4-34.8) 32.2 (30.3-35.3) 30.2 (27.1-34.7) Neck length, mm 9.0 (5.0-18.0) 11.0 (5.0-20.0) 7.5 (4.5-16.3) Suprarenal angulation, deg 14.0 (6.0-20.0) 10.0 (6.0-17.0) 14.0 (5.3-23.0) Infrarenal angulation, deg 16.0 (10.0-28.0) 16.0 (10.0-24.0) 19.5 (11.3-37.3) Neck thrombus thickness, mmb 1.7 (0.0-2.5) 2.1 (1.0-2.6) 0.0 (0.0-2.2)
Neck thrombus circumference, degb 82.0 (0.0-164.0) 99.0 (15.0-180.0) 0.0 (0.0-106.5)
Neck calcium thickness, mmb 1.0 (0.0-1.7) 1.2 (0.0-1.7) 0.0 (0.0-1.2)
Neck calcium circumference, degb 13.0 (0.0-37.0) 16.0 (0.0-37.0) 0.0 (0.0-31.8)
Conical neck 33 (65) 21 (68) 12 (60)
Tapered 1 (2) 1 (3) 0 (0)
Conical 32 (63) 20 (65) 12 (60)
Hostile neck 48 (94) 30 (97) 18 (90)
aContinuous data are presented as the median (interquartile range); categorical data are given as the number
(percentage).
bNot measured for revision cases.
patient received 4 and another received 5 EndoAnchors). Of the 2 therapeutically treated patients, one received 6 EndoAnchors and the other 4 EndoAnchors.
Circumferential deployment (4 quadrants) of EndoAnchors was achieved in 10 patients. Deployment within 270° of the circumference (3 quadrants) was achieved in 22 patients. In 9 patients, EndoAnchors were deployed in one half (2 quadrants) of the circumference, whereas in 8 patients 2 quadrants were also used, but they were on opposite sides of the neck. In the remaining 2 patients, the EndoAnchors were deployed in 1 quadrant of the circumference owing to treatment of a type IA endoleak in combination with almost circumferential thrombus in the aortic neck.
EndoAnchor deployment was successful in 337 (99%). One EndoAnchor fractured during implantation due to dense calcification in the aortic wall. The distal part of the fractured EndoAnchor remained within the endograft; the other part remained within the endoguide and was retrieved. Another 2 EndoAnchors dislocated during implantation and had to be snared and removed. These complications occurred in the first 6 patients (#2 and #6) and were due to the fact that not all lengths of endoguides were available at that time (year 2010). Bare metal stents [2 AndraStent (Andramed, Reutlingen, Germany) and 1 Palmaz (Cordis Corporation, a Cardinal Health company, Milpitas, CA, USA)] were deployed in 3 patients because of type Ia endoleaks after the use of EndoAnchors. The median procedure time was 100 minutes (IQR 90-120) and median estimated blood loss was 150 mL (IQR 100-250). A total of 10 (20%) type Ia endoleaks were still present on the completion angiograms; 4 (13%) vs 6 (30%) in the prophylactic and therapeutic arms, respectively.
Complications and reinterventions
Median follow-up was 23.9 months (IQR 13.4-35.6), with follow-up imaging involving CTA (61%), duplex ultrasound (38%), or MRA (1%). Between the first and latest follow-up imaging, the aortic neck increased a median of 2.5 mm (IQR 0.6-3.8). There was no new-onset hemodialysis, and no endograft migration occurred during this time frame. Major complications arose in 11 (22%) of 51 patients: type IA endoleak (6, 12%), type IB endoleak (5, 10%), chimney stent-graft occlusion (1, 2%), endograft limb occlusion (1, 2%), aneurysm rupture (1, 2%) due to type IV endoleak, and endograft explantation (1, 2%) due to infection. The binary logistic regression did not identify any significant predictors of major complications (Table 8.4).
Table 8.3. Baseline anatomic characteristics.a
Variable Total (n=51) Prophylactic (n=31) Therapeutic (n=20) Indication
Elective 50 (98) 30 (97) 20 (100)
Acute 1 (2) 1 (3) 0 (0)
Type of endograft
Valiant cuff (in AFX unibody) 3 (6) 2 (7) 1 (5) Cook cuff (in AFX unibody) 1 (2) 0 (0) 1 (5)
Endurant 37 (73) 27 (84) 10 (50)
Excluder 1 (2) 0 (0) 1 (5)
Talent 5 (10) 0 (0) 5 (25)
Zenith 4 (8) 2 (7) 2 (10)
Total EndoAnchors 340 (100) 187 (55) 153 (45) EndoAnchors per patient 6 (5-7) 6 (5-7) 6 (5-9) Distribution of EndoAnchors 1 Quadrant 2 (4) 1 (3) 1 (5) 2 Quadrants 17 (33) 9 (29) 8 (40) 0-180° 9 (18) 4 (13) 6 (30) Opposing sides 8 (16) 5 (16) 2 (10) 3 Quadrants 22 (43) 14 (45) 8 (40) 4 Quadrants (circumferential) 10 (20) 7 (23) 3 (15) Procedure duration, min 100.0 (90-120) 120.0 (90-120)b 100.0 (70-120)
Estimated blood loss, mL 150.0 (100-250) 150.0 (100-237.5)c 200.0 (100-300)d
Proximal adjunct procedures
Cuff 16 2 14
AndraStent/Palmaz stent 3 1 2
Chimney stent graft (all single) 8 5 3 Distal adjunct procedures
Iliac extensionse 17 7 10
Iliac branch device 2 1 1
Coils in the IIA 1 1 0
Amplatzer plug in the IIA 1 0 1
Type IA endoleak at completion 10 (20) 4 (13) 6 (30) Intensive care unit admission 2 (4) 2 (7) 0 (0) Length of hospitalization, d 4 (4-6) 4 (4-6) 4 (4-5) Imaging follow-up, mo 23.9 (13.4-35.6) 23.9 (14.1-34.9) 24.4 (11.6-39.7)
Abbreviation: IIA, internal iliac artery.
aContinuous data are presented as the median (interquartile range); categorical data are given as the number
(percentage).
bData available on 23 patients. cData available on 24 patients. dData available on 19 patients. eSeventeen extensions in 11 patients.
Table 8.4. Binary logistic regression of major complications. Predictors of major
complications (binary)
Coefficient Standard error Odds ratio P value
Maximum sac diameter, mm -0.049 0.032 1.050 .126 Aortic neck diameter, mm
Highest renal artery -0.012 0.233 1.012 .958
Baseline (lowest renal artery) -0.174 0.471 1.190 .712 5 mm distal to lowest renal artery -0.022 0.589 0.978 .970 10 mm distal to lowest renal artery -0.281 0.484 0.755 .562 15 mm distal to lowest renal artery -0.285 0.268 1.329 .289
Neck length, mm -0.031 0.045 1.032 .486
Suprarenal angulation, deg -0.016 0.051 1.016 .753 Infrarenal angulation, deg -0.034 0.038 0.966 .364 Neck thrombus thickness, mma -0.499 0.378 1.646 .187
Neck thrombus circumference, dega -0.006 0.008 0.994 .493
Neck calcium thickness, mma -0.054 0.775 0.948 .945
Neck calcium circumference, dega -0.023 0.022 1.023 .293
Number of EndoAnchors -0.210 0.147 1.233 .153
aNeck thrombus and calcium thickness and circumference were not measured for revision cases.
There were 17 reinterventions in 13 patients, as shown in Table 8.5. Freedom from any reintervention was estimated as 83.3% (95% CI 72.7% to 93.9%) at 1 year and 80.5% (95% CI 68.9% to 92.1%) at 2 years (Figure 8.1). The freedom from a proximal neck– related reintervention was 95.4% (95% CI 89.1% to 100%) and 92.2% (95% CI 83.6% to 100%) at 1 and 2 years, respectively (P = .056).
Type IA endoleaks
At first postoperative imaging, 9 of the 10 type IA endoleaks that were present at completion angiography had resolved. In addition to the residual postoperative leak noted above, 2 new type IA endoleaks were seen on the first postoperative (<60 days) CT scan. One was treated with an AndraStent 56 days after the EndoAnchor procedure (Table 8.5, patient #22); at completion angiography the endoleak was absent, but an extravasation observed at the origin of the renal artery required embolization. The patient is alive without type IA endoleak at 44 months but has chronic renal insufficiency (stage 4) without the need for hemodialysis.
One endoleak (patient #44) was treated with banding of the infrarenal aorta; 47 months later a type IV endoleak was suspected, after which the aneurysm ruptured. A Nellix endosystem (Endologix Inc, Irvine, CA, USA) was deployed within the previous Excluder endograft. Completion angiography showed absence of an endoleak, and the patient is alive at 64 months. The other patient (#26) did not receive a reintervention;
the endoleak had resolved at 10 months, and the patient is alive at 34 months.
Three other endoleaks were detected over the course of follow-up. All were treated successfully with a Valiant cuff (patient #29) and 2 AndraStents (patients #20 and #37). However, subsequent CT imaging in patient #20 showed a persistent type IA endoleak that required banding 16 months after the reintervention.
Kaplan-Meier survival analysis estimated that freedom from type IA endoleak for the entire cohort was 93.8% (95% CI 86.9% to 100%) at 1 year and 87.3% (95% CI 76.5% to 98.1%) at 2 years. Comparing the prophylactic and therapeutic arms, freedom from type Ia endoleak estimates were 93.3% (95% CI 84.3% to 100%) vs 94.4% (95% CI 83.8% to 100%) after 1 year and 88.9% (95% CI 76.9% to 100%) vs 84.0% (95% CI 62.4% to 100%) after 2 years, respectively (P = .814; Figure 8.2).
Mortality
Aneurysm-related mortality in this cohort was 5.9% (3/51). Two patients died within 30 days after elective EVAR (4%). One patient (#8) in the prophylactic group developed pneumosepsis and died 13 days after the procedure. The other patient (#51), from the therapeutic group, suffered congestive heart failure and developed multiorgan failure, expiring 14 days after the baseline procedure. During follow-up, one therapeutically treated patient (#14) received a median laparotomy and subsequent aortotomy because
Figure 8.1. Kaplan-Meier estimates of the freedom from any reintervention and proximal neck– related reintervention for the entire cohort (P = .056).
of a rapid increase in AAA size; 800 mL of hygroma were removed. No endoleaks could be determined during surgery, and the endograft was left in place. The following day, a relaparotomy was performed, and 3 L of serosanguinous fluid was removed; no explantation of the endograft was performed. Postoperatively, the patient became septic and died of multiorgan failure 9 months after the initial procedure. No additional aneurysm-related deaths occurred during further follow-up.
Freedom from all-cause mortality was 92.0% (95% CI 84.6% to 99.4%) at 1 year and decreased to 84.8% (95% CI 74.4% to 95.2%) at 2 years. Cumulative freedom from aneurysm-related mortality at 1 year was 94.0% (95% CI 87.3% to 100%), which remained the same at 2 years (P = .020; Figure 8.3).
Figure 8.2. Kaplan-Meier estimates of the freedom from type IA endoleak for the entire cohort and the prophylactic and therapeutic EndoAnchor implant treatment arms (P = .814).
Figure 8.3. Kaplan-Meier estimates of the freedom from all-cause and aneurysm-related mortality for the entire cohort (P = .020).
Early (<60 days) La te(60-days to 2years) tient Complica tion R einter vention Complica tion R einter vention Complica tion R einter vention Outcome
ophylactic EndoAnchor implanta
tion Pneumosepsis -Died 13 days a
fter the baseline
pr
ocedur
e
a
Type IA endoleak and r
enal dysfunction AndraS tent and emboliza tion right renal artery -Reduced r
enal function, but
no need f or hemodialysis. Alive at 44 months -Type IB endoleak Distal extension right endogra
ft limb -Alive a t 72 months Type IA endoleak -Endoleak r esolved without tr ea tment, alive a t 34 months
-Type IA and IB endoleak
s
V
aliant cuff and EndoAnchor implants and distal extensions both sides
-Died 33 months a fter baseline pr ocedur e o f causes unr ela ted to the pr ocedur e or aneurysm -Gra ft in fection (S . aur eus and Bactriodetes) Complete explant in fected endogra ft and EndoAnchor implants -Alive a t 22 months Hema
toma left arm
after single ch-EV AR Sur gical evacua tion b -Alive a t 15 months
Occlusion left endogra
ft limb -Mild claudica tion, no need for r eintervention. Alive a t 22 months
-Type IA and IB endoleak
s
Both AndraS
tent and distal
extensions -Alive a t 60 months Type IB endoleak IBD complica ted by ruptur e o f the
distal IIA. Sur
gical repair r equir ed -Alive a t 54 months -Type IB endoleak s both sides Distal extensions -Alive a t 54 months Early (<60 days) La te(60-days to 2years) tient Complica tion R einter vention Complica tion R einter vention Complica tion R einter vention Outcome
ophylactic EndoAnchor implanta
tion -Ser oma ca vity left gr oin Sur gical ex cochlea tion -Alive a t 19 months tion -Rapid incr ease in AAA siz e, no type I , II ,
or III endoleak detected
Explora tion, r emoval o f 800 mL o f hygr oma via aortotomy Septic Relapar otomy , removal of 3 L o f ser osanguinous fluid Pa tient died o f multior gan failur e 9 months a fter the baseline pr ocedur e c Hema
toma left arm
after single ch-EV AR Sur gical evacua tion b
Renal insufficiency due to stenosis C
G Selective ca theteriza tion and r e-stenting. A ttempts a t recanaliza tion o f right r enal artery unsuccessful -Pa tient’s r educed r enal function r
emains stable. Alive
at 15 months -Type IA endoleak AndraS tent Incr easing
diameter due to persistent type IA endoleak Banding pro ximal aorta Alive a t 52 months Type IA endoleak Banding pr o ximal aorta Type IV endoleak and ruptur e
Nellix device within main device
-Alive a t 64 months Occlusion C G -Died 9 months a fter baseline pr ocedur e, not r ela ted to
aneurysm nor endogra
ft Decompensa tio cor dis and multior gan failur e -Died 1 4 days a
fter the baseline
pr ocedur e a evia tions: AAA, abd
ominal aortic aneurysm;
ch-EV
AR, chimney endovascular aneurysm r
epair; C
G, chimney gra
ft; EIA, external iliac artery; IBD
, iliac branch device;
, pr
ophylactic; T
, therapeutic.
ela
ted mortality within 30 days o
f the baseline pr ocedur e; bReintervention bef or e first f ollow-up imaging; cAneurysm-r ela
ted mortality during f
ollow-up. .5 . Complica tions and r einterventions.
8
Early (<60 days) La te(60-days to 2years) tient Complica tion R einter vention Complica tion R einter vention Complica tion R einter vention Outcome
ophylactic EndoAnchor implanta
tion Pneumosepsis -Died 13 days a
fter the baseline
pr
ocedur
e
a
Type IA endoleak and r
enal dysfunction AndraS tent and emboliza tion right renal artery -Reduced r
enal function, but
no need f or hemodialysis. Alive at 44 months -Type IB endoleak Distal extension right endogra
ft limb -Alive a t 72 months Type IA endoleak -Endoleak r esolved without tr ea tment, alive a t 34 months
-Type IA and IB endoleak
s
V
aliant cuff and EndoAnchor implants and distal extensions both sides
-Died 33 months a fter baseline pr ocedur e o f causes unr ela ted to the pr ocedur e or aneurysm -Gra ft in fection (S . aur eus and Bactriodetes) Complete explant in fected endogra ft and EndoAnchor implants -Alive a t 22 months Hema
toma left arm
after single ch-EV AR Sur gical evacua tion b -Alive a t 15 months
Occlusion left endogra
ft limb -Mild claudica tion, no need for r eintervention. Alive a t 22 months
-Type IA and IB endoleak
s
Both AndraS
tent and distal
extensions -Alive a t 60 months Type IB endoleak IBD complica ted by ruptur e o f the
distal IIA. Sur
gical repair r equir ed -Alive a t 54 months -Type IB endoleak s both sides Distal extensions -Alive a t 54 months Early (<60 days) La te(60-days to 2years) tient Complica tion R einter vention Complica tion R einter vention Complica tion R einter vention Outcome
ophylactic EndoAnchor implanta
tion -Ser oma ca vity left gr oin Sur gical ex cochlea tion -Alive a t 19 months tion -Rapid incr ease in AAA siz e, no type I , II ,
or III endoleak detected
Explora tion, r emoval o f 800 mL o f hygr oma via aortotomy Septic Relapar otomy , removal of 3 L o f ser osanguinous fluid Pa tient died o f multior gan failur e 9 months a fter the baseline pr ocedur e c Hema
toma left arm
after single ch-EV AR Sur gical evacua tion b
Renal insufficiency due to stenosis C
G Selective ca theteriza tion and r e-stenting. A ttempts a t recanaliza tion o f right r enal artery unsuccessful -Pa tient’s r educed r enal function r
emains stable. Alive
at 15 months -Type IA endoleak AndraS tent Incr easing
diameter due to persistent type IA endoleak Banding pro ximal aorta Alive a t 52 months Type IA endoleak Banding pr o ximal aorta Type IV endoleak and ruptur e
Nellix device within main device
-Alive a t 64 months Occlusion C G -Died 9 months a fter baseline pr ocedur e, not r ela ted to
aneurysm nor endogra
ft Decompensa tio cor dis and multior gan failur e -Died 1 4 days a
fter the baseline
pr ocedur e a evia tions: AAA, abd
ominal aortic aneurysm;
ch-EV
AR, chimney endovascular aneurysm r
epair; C
G, chimney gra
ft; EIA, external iliac artery; IBD
, iliac branch device;
, pr
ophylactic; T
, therapeutic.
ela
ted mortality within 30 days o
f the baseline pr ocedur e; bReintervention bef or e first f ollow-up imaging; cAneurysm-r ela
ted mortality during f
ollow-up.
.5 continued.
DISCUSSION
In this 51-patient single-center experience of EndoAnchor use during EVAR and ch-EVAR, the 20% type IA endoleak rate at completion was higher compared to results from the ANCHOR cohort (6% to 9.1%).9-11 However, 9 of the endoleaks had resolved at first postoperative CT imaging, which is in line with the observation of Bastos Gonçalves et al.20 that >50% of the type IA endoleaks present at completion angiography spontaneously resolve on the first postoperative scans. Furthermore, the high rate of spontaneous resolution suggests that the combination with EndoAnchors makes the course of type IA endoleaks more benign. Although small gutters may exist, they can resolve within 30 days (possibly due to thrombus formation within the gutter and delayed adaptation of the endograft toward the aortic wall).21
The literature has shown that the occurrence of type IA endoleaks after EVAR is significantly higher in patients with hostile neck anatomy,3,22,23 which has been associated with a fourfold increased risk of type IA endoleaks at 1 year.3 Additionally, a significant increase in late type I endoleaks was observed in hostile vs favorable necks in a meta-analysis of studies (9.6% vs 1.9%).24
At 1-year follow-up there was a lower incidence of type IA endoleaks in this cohort compared to the first 100 patients with 1-year follow-up in the ANCHOR database (5.9% vs 8.1%). Moreover, 1-year freedom from type IA endoleak was slightly better than that reported by Jordan et al.10 (93.8% vs 89.4%), and the 87.3% 2-year rate was just below their 1-year results. Muhs et al.14 showed a high 97% freedom from type IA endoleak in a subset of 87 prophylactically treated ANCHOR patients, which is considerably higher than the 88.9% reported in our cohort. A possible explanation for this discrepancy may be the larger percentage of patients with hostile necks, greater median neck diameters at different levels below the renal arteries, and shorter median neck length in the current cohort, contributing to a greater risk of type IA endoleak during follow-up.17,22
Jordan et al.13 showed a 1.9% 30-day mortality and 3.4% all-cause mortality at 1 year for prophylactically treated patients, which matched the 3.2% 30-day mortality and all-cause mortality at 1 year for the prophylactic arm in our series. An explanation for the higher rate for all-cause mortality at 1 year in the entire cohort compared to ANCHOR results (7.8% vs 3.5%–4.7%10,11) may be that one of the exclusion criteria of the ANCHOR study is a life expectancy <1 year.17 Patients ineligible for enrolment in the ANCHOR study had been treated with EndoAnchors and where thus included in the current series.
Moreover, our 85% freedom from all-cause mortality at 2 years compared well with estimates reported for EVAR without EndoAnchors in challenging aortic necks,23,24
fenestrated EVAR25-27 (FEVAR), and ch-EVAR.28,29 The 94% freedom from related mortality in our cohort corresponded to the late freedom from aneurysm-related mortality for standard EVAR or FEVAR in challenging neck anatomy.30 While open repair shows freedom from aneurysm-mortality >96%,30 patients with ASA III class and prior aortic procedures were preferably treated using EVAR in the current series. Of note, 4 patients in our series had neck diameters ≥33 mm and were treated with a Valiant cuff or ch-EVAR because open surgery was absolutely contraindicated due to cardiopulmonary comorbidity. None of the patients in this cohort was treated with FEVAR because of less optimal anatomy (small iliac or renal arteries or severe suprarenal or infrarenal angulation). Additionally, the 2- to 3-month waiting time for a fenestrated endograft was considered too long for some patients.
There was one endograft explantation after infection in our cohort. Explantation of an endograft with EndoAnchors may be more challenging. Before the aneurysm sac was opened, the aorta was cross-clamped above the renal arteries. After aortotomy the endograft was transected just below the EndoAnchors, which were unscrewed. Thereafter, the proximal part of the main body was removed.
Eight patients were treated with a single ch-EVAR procedure and EndoAnchors; none developed type IA endoleaks during follow-up. No proximal neck–related reinterventions were performed, and only 1 chimney stent-graft occlusion was observed. In these ch-EVAR cases, EndoAnchors were preferably deployed circumferentially in the remaining short neck below the chimney stent-graft to ensure adequate seal between the main device and aortic wall and to prevent the EndoAnchors from compressing the chimney stent graft. If this neck length was not available, the EndoAnchors were deployed next to the chimney graft to significantly minimize gutter formation.21 However, this is technically challenging; one must prevent implantation too close to the chimney graft to avoid compression, but deployment that is too far from the chimney will not prevent gutter formation. Of note, EndoAnchors should be implanted along the chimney grafts only in cases of gutter-associated endoleaks.21 Ideally, EndoAnchor deployment should be evenly divided over the aortic circumference per the IFU to achieve the intended fixation and sealing. However, in ~80% of the cases, EndoAnchors were deployed in fewer than the intended 4 quadrants. This noncircumferential deployment was related to thrombus/calcium load present in the aortic neck or high angulation of the aortic neck, which made positioning of the endoguide challenging. Maldeployment of EndoAnchors can be caused by operator inexperience or mismatch between the length of the endoguide tip and the diameter of the infrarenal aorta. The length of the endoguide should always be chosen to conform to the diameter of the infrarenal neck. Notably, there is a learning curve associated with the use of EndoAnchors; 9 different vascular surgeons (including fellows) performed
the interventions in this cohort. Because of this learning curve (4–6 cases), it is advised to initially use EndoAnchors in patients without challenging aortic neck anatomy. In primary cases, endoleaks were sometimes identified after deployment of the main device. In case of an observed endoleak, the first decision was to use EndoAnchors (thus therapeutic EndoAnchor use in primary patients). If needed, all 10 EndoAnchors were used. In case of persistent endoleak after deployment of the EndoAnchors, a proximal extension cuff was deployed only if the distance between the lowest renal artery and the top of the fabric of the main body was >3 mm. If the endoleak still persisted after these interventions, the type IA endoleak was accepted and a 1-month CT scan was awaited.
Instead of primary EVAR with additional EndoAnchors, other therapeutic options exist such as open repair, ch-EVAR, or FEVAR. In the majority of patients in this study cohort, the risks of open repair were high due to comorbidities or former abdominal surgery. In some of the cases it was the preference of the patient to undergo EVAR instead of open surgery. Patients were ineligible for ch-EVAR or FEVAR due to small visceral arteries, logistic reasons, or aortic arch and subclavian artery anatomic restrictions.
Abdominal radiography was not used in conjunction with contrast-enhanced ultrasound, and in this cohort the majority of the follow-up was performed with CT imaging. Although EndoAnchors cause metal artifacts on CT scans, it is still feasible to assess migration, endoleaks, and proper deployment of EndoAnchors into the aortic wall on these scans, which is important to prevent type IA endoleaks during follow-up.31
Limitations
The main limitations of this study are the retrospective design and relatively small number of patients. Additionally, because this is a consecutive cohort of patients who were not included in the ANCHOR study, the risk of selection bias has to be taken into account. Moreover, the effect of the different distributions of EndoAnchors on outcomes was not investigated in this cohort. Additionally, the penetration of the EndoAnchors in the aortic wall was not defined in this study, and its effect on the patient outcome was not assessed. It was assumed that the correct endoguide size was used during each intervention in this cohort. However, since the size was not mentioned in the majority of the cases, no analysis could be performed on the effect of correct or incorrect endoguide size on the technical success rate.
It should be noted that the Endurant stent-graft is the workhorse in our hospital, and thus the majority of patients in this cohort had an Endurant device. Today, the Endurant stent-graft with EndoAnchors is approved in the United States for necks as
short as 4 mm. However, at the time of EndoAnchor implantation in this patient cohort, this approval did not exist, and neck length <10 mm was used as a hostile neck criterion. Because of the small patient numbers treated with other endoprostheses, no analyses were performed between stent-graft models and clinical outcomes. Moreover, no analysis was made of radiation dose associated with the use of EndoAnchors during EVAR, but a previous study has demonstrated that radiation dose was not significantly increased during EVAR with EndoAnchors.32
CONCLUSION
EndoAnchors are helpful in the endovascular treatment of unfavorable proximal aortic necks and can also be used safely in ch-EVAR procedures. Ninety percent of the type IA endoleaks present at completion angiography had resolved at the first postoperative CT and did not need reintervention. At 2-year follow-up, the overall freedom from type IA endoleak, aneurysm-related mortality, and proximal neck–related reintervention were acceptable taking into account the challenging infrarenal neck characteristics. The new approval of Endurant combined with EndoAnchors for ≥4-mm aortic necks increases the applicability of this approach, especially in a challenging cohort with hostile neck anatomy. EndoAnchors are reliable adjuncts to the armamentarium of the endovascular specialist. Additional data, larger numbers, and longer follow-up are needed to confirm the patient population that can truly benefit from EndoAnchors.
DECLARATION OF CONFLICTING INTERESTS
The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Jean-Paul P. M. de Vries is a consultant on the Scientific Advisory Board for Medtronic, Inc. Jan-Albert Vos is a consultant on the Peripheral Vascular Advisory Board for Medtronic, Inc.
FUNDING
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by a restricted grant from Medtronic, Inc.
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