Endovascular aneurysm sealing for abdominal aortic aneurysm

24 Pages·2015·0.28 MB·English

by  Vassilia Verdiel

IP 1283 [IPGXXX]

NATIONAL INSTITUTE FOR HEALTH AND
CARE EXCELLENCE
INTERVENTIONAL PROCEDURES PROGRAMME
Interventional procedure overview of endovascular
aneurysm sealing for abdominal aortic aneurysm
The aorta is the largest artery (blood vessel) in the body. An abdominal aortic
aneurysm is a swelling of part of the aorta, inside the abdomen. The swelling
happens because there is a weakness in the wall of the aorta. In endovascular
aneurysm sealing, 2 stents (tiny tubes) are inserted through a small cut in the
skin and then through the arteries to the aneurysm. The aneurysm is sealed off
around the stents with a polymer.
Introduction
The National Institute for Health and Care Excellence (NICE) has prepared this
interventional procedure (IP) overview to help members of the Interventional
Procedures Advisory Committee (IPAC) make recommendations about the safety
and efficacy of an interventional procedure. It is based on a rapid review of the
medical literature and specialist opinion. It should not be regarded as a definitive
assessment of the procedure.
Date prepared
This IP overview was prepared in January 2015.
Procedure name
 Endovascular aneurysm sealing for abdominal aortic aneurysm.
Specialist societies
 British Society of Interventional Radiology.
 Vascular Society of Great Britain and Ireland.
IP overview: Endovascular aneurysm sealing for abdominal aortic aneurysm
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Description
Indications and current treatment
An abdominal aortic aneurysm (AAA) is a dilatation of part of the aorta. In some
cases aneurysms may leak or rupture, causing internal bleeding and death.
Some patients with a ruptured aneurysm will survive long enough to have
surgical repair but the mortality is high. If a large aneurysm is detected, then
treatment is often advised to prevent rupture.
The traditional treatment for AAA is open surgical repair. Endovascular aneurysm
repair (EVAR) is a less invasive alternative method which is now commonly used.
This is done by inserting a stent graft via catheters in the femoral arteries. The
stent graft is held in place by self-expanding radial force, supplemented by
balloon expansion and by integral hooks, which attach it to the wall of the aorta.
A snug fit is important to prevent blood from flowing between the stent graft and
the aorta (an endoleak) and to prevent the stent graft from migrating.
What the procedure involves
Endovascular aneurysm sealing is a new approach to EVAR. It uses a polymer
filling to form a rubbery cast within the aneurysm sac, which excludes it from the
circulation. The aim is to stabilise the stent graft position and reduce the rate of
endoleaks and repeat interventions.
With the patient under general, regional or local anaesthesia, and using
fluoroscopic guidance, guidewires are introduced via each femoral artery and
advanced through the aneurysm. A device (consisting of integral catheters with a
balloon expandable stent and attached endobags) is advanced over each
guidewire and carefully positioned within the aneurysm. The catheters are
connected to an external console and a vacuum is created using a syringe, which
prepares the endobags. The balloons are inflated to expand the stents. A
biostable polyethylene glycol polymer is injected through the catheters into the
endobags under pressure monitoring. As the polymer is injected the endobags
expand to fill the aneurysm sac, sealing it off from the circulation and holding the
stent grafts in place.
Possible advantages of using endovascular aneurysm sealing over standard
EVAR alone include its use for aneurysms with shorter necks, and the reduced
risk of type 2 endoleaks (persistent filling of the aneurysm sac by retrograde flow
in the lumbar and inferior mesenteric arteries).
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Literature review
Rapid review of literature
The medical literature was searched to identify studies and reviews relevant to
endovascular aneurysm sealing for abdominal aortic aneurysm (AAA). The
following databases were searched, covering the period from their start to 27
January 2015: MEDLINE, PREMEDLINE, EMBASE, Cochrane Library and other
databases. Trial registries and the Internet were also searched. No language
restriction was applied to the searches (see appendix C for details of search
strategy). Relevant published studies identified during consultation or resolution
that are published after this date may also be considered for inclusion.
The following selection criteria (table 1) were applied to the abstracts identified by
the literature search. Where selection criteria could not be determined from the
abstracts the full paper was retrieved.
Table 1 Inclusion criteria for identification of relevant studies
Characteristic Criteria
Publication type Clinical studies were included. Emphasis was placed on identifying
good quality studies.
Abstracts were excluded where no clinical outcomes were
reported, or where the paper was a review, editorial, or a
laboratory or animal study.
Conference abstracts were also excluded because of the difficulty
of appraising study methodology, unless they reported specific
adverse events that were not available in the published literature.
Patient Patients with abdominal aortic aneurysm.
Intervention/test Endovascular aneurysm sealing.
Outcome Articles were retrieved if the abstract contained information
relevant to the safety and/or efficacy.
Language Non-English-language articles were excluded unless they were
thought to add substantively to the English-language evidence
base.

List of studies included in the IP overview
This IP overview is based on 127 patients from 1 non-randomised comparative1
study and 2 case series2-3.
Other studies that were considered to be relevant to the procedure but were not
included in the main extraction table (table 2) have been listed in appendix A.

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Table 2 Summary of key efficacy and safety findings on endovascular aneurysm sealing for
AAA
Study 1 Kisis K (2012)
Details
Study type Non-randomised prospective cohort study
Country Latvia
Recruitment period 2008-2011
Study population and n=45 (22 endovascular aneurysm sealing [EVAS] versus 23 open surgery [OS]) consecutive patients
number with abdominal aortic aneurysm (AAA)
Age and sex Mean 68.5 years; 83% (33/40) male (data only provided for participants who completed study)
Patient selection criteria In both groups, AAA anatomy allowed for either open surgery or endovascular repair. The patients were
included in the EVAS group during the period when Nellix devices were available. All other patients were
allocated to the OS group.
Technique Endovascular aneurysm sealing using Nellix or open surgical approach.
Follow-up 1 year
Conflict of The authors stated no conflict of interest.
interest/source of
funding
Analysis
Follow-up issues:
 One patient from the EVAS group refused to participate in the study and 4 patients died during the study period
(1 patient in the EVAS group and 3 patients in the OS group), leaving 20 patients in the OS group and 20 patients in
the EVAS group.
Study design issues:
 Quality of life was the only outcome measured in this study. The SF-36 questionnaire (RAND corporation, higher
score indicates better QoL) was used in order to compare the quality of life before the procedure, and 1 month and
1 year after the procedure.
 Before the operation, an attending physician discussed the survey questions with each patient. After the hospital
discharge, the questionnaires were administered by phone.
 The SF-36 questionnaire was translated from English into Latvian and Russian and the patients were allowed to
choose their preferred language in order to avoid confusion that would affect the reliability of the results.
 p values were calculated using t-tests.
Study population issues:
 The EVAS group had more patients with benign prostatic hyperplasia than the OS group (20% [4/20] versus 5%
[1/20], P<0.05) and aneurysmal widening of other blood vessels (20% [4/20] versus 0% [0/20], P<0.05).
 Patient overlap with Krievins (2011) study (in table 2) and Donayre (2011) study (in Appendix A).
Other issues: None.
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Key efficacy and safety findings
Efficacy Safety
Number of patients analysed: 40 (20 EVAS versus 20 OS) Gastrointestinal
disorders
associated with

surgery
Results of the SF-36 Questionnaire subscales (mean [SD])
 EVAS group:
Before the 1 month after the 1 year after the 10%
procedure procedure procedure
 OS group: 60%
Component
EVAS OS p EVAS OS p EVAS OS p
 p<0.001
(n=20) (n=20) (n=20) (n=20) (n=20) (n=20)

Physical functioning 76 71 (8) NS 70 (7) 43 (9) <0.001 68 59 (9) 0.016

(10) (10)
Blood loss during
Role-physical 66 66 NS 60 (13) 34 (12) <0.001 65 57 NS
surgery (mean,
(12) (12) (13) (11)
SD)
Bodily pain 61 (8) 63 (8) NS 60 (10) 28 (10) <0.001 60 27 (8) <0.001
 EVAS group:
(11)
250 mL (SD,
General health 64 65 NS 63 (11) 60 (13) NS 68 65 (8) NS 150)
(10) (10) (10)
 OS group:
Vitality 59 59 NS 52 (5) 30 (10) <0.001 58 54 (8) NS 1025 mL (SD,
(11) (11) (10) 205)
Social functioning 66 66 NS 61 (9) 36 (11) <0.001 54 45 (6) 0.007  p<0.01
(10) (10) (10)
 3 patients from
Role-emotional 63 63 NS 58 (15) 35 (7) <0.001 57 42 0.009 the OS group
(10) (10) (15) (15) needed blood
Mental health 63 (6) 64 NS 65 (10) 53 (13) 0.002 54 (9) 51 NS transfusion.
(10) (10)
Physical component 48 (4) 48 (3) NS 47 (3) 38 (3) <0.001 48 (4) 42 (3) <0.001
summary (PCS)
Mental component 44 (3) 45 (3) NS 44 (4) 37 (3) <0.001 40 (4) 39 (4) NS
summary (MCS)

Abbreviations used: EVAS, endovascular aneurysm sealing; QoL, quality of life; NS, not significant; OS, open surgery; SD, standard
deviation

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Study 2 Krievins DK (2011)
Details
Study type Case series
Country 4 sites (Latvia, New Zealand, Venezuela and Colombia)
Recruitment period 2008-2010
Study population and n=34 patients with AAA (mean diameter 5.8± 0.8 cm [SD]).
number
Age and sex Mean age 71 years; 91% (31/34) male
Patient selection criteria Aneurysm size 4.5 cm or greater, aneurysm size twice the diameter of the infrarenal neck and documented
rate of aneurysm enlargement >10% in 1 year with aortic neck length 10 mm or greater.
After review of the clinical results from the first 21 patients, the study protocol was modified to allow inclusion
of patients with shorter aortic necks (5 mm or greater).
Technique Nellix (Endologix).
Follow-up Mean 15 months
Conflict of The study was funded by Nellix.
interest/source of
funding
Analysis
Follow-up issues:
 Contrast CT scans were done on all patients prior to treatment and within 30 days of treatment. Follow-up CT scans
were done at 6, 12 and 24 months.
 DICOM (Digital Imaging and Communications in Medicine) data sets of all pre- and post-operative CT scans were
sent for independent Core Laboratory image analysis.
 Follow-up CT scan measurements included aneurysm diameter and cross-sectional area and endograft position with
respect to the superior mesenteric artery (SMA) and vertebral body reference points.
Study design issues:
 The first post-procedure CT scan (within 30 days) was used as the baseline for comparison of quantitative
morphological changes on follow-up CT scans.
 Statistical comparison of individual measures was performed using the paired t-test or Fisher’s exact test.
Study population issues:
 50% (17/34) of patients met the inclusion criteria for Food and Drug Administration (FDA)-approved endografts
(favourable anatomy); 50% (17/34) had 1 or more adverse anatomic feature: 24% (8/34) neck length <10 mm, 9%
(3/34) neck angle >60º (9%) and 38% (13/34) iliac diameter >23 mm.
 Patient overlap with Kisis (2012) study (in Table 2) and Donayre (2011) study (in Appendix A).
Other issues: None.
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Key efficacy and safety findings
Efficacy Safety
Number of patients analysed: 34 Mortality
 Technical success (successful deployment and implantation Event 30 days 6 months 1 year 2 years Total
of the endoprostheses): 100% (34/34) (0-30 (31-182 (183- (366- n=34
days) days) 365 730
 Conversion to surgery: 0% (0/34)
n=34 n=33 days) days)

n=32 n=5
Endoleak
Mortality 3%* 0% 3% 0% 6%
Event 30 days 6 months 1 year 2 years Total (1/34) (1/32) (2/34)
(0−30days) (31−182 (183−365 (366−730 n=34 Aneurysm- 3%* 0% 0% 0% 0%
n=34 days) days) days) related (1/34)
n=33 n=32 n=5 mortality
Any 6% (2/34) 3% 3% 0% 6% *These events occurred in the same patient; the death is considered
endoleak (1/33) (1/32) (2/34) aneurysm-related as this occurred within the 30 days following the
procedure.
 One patient had a proximal type I endoleak, which was seen
 One patient died during the 30-day post-operative period of
on the 30-day CT scan and was fully resolved at 60 days.
multisystem organ failure. The authors state that this death
There was no endoleak on the 6-month and 12-month CT
was not device-related “as evidenced by post-procedure CT
scans.
scan and post-mortem examination of the aneurysm and
 The other patient had a distal type I endoleak because the device”.
device endobag was too short to fully fill the aneurysm sac
 The other patient died at 10 months of congestive heart
and due to the nonavailability of Nellix iliac extenders early in
failure; this patient had a normal CT scan at 6 months.
the clinical experience. This endoleak persisted with no
change in aneurysm size for 12 months. An elective  Number of patients with major adverse events: 12% (4/34), 2
secondary endovascular procedure was performed at with favourable anatomy and 2 with adverse anatomy.
15 months with placement of coils and an iliac extender,
resulting in complete resolution of the endoleak.
Mean estimated blood loss (SD): 165±107 ml (range 35-
400 ml).
Secondary interventions
Event 30 days 6 months 1 year 2 years Total
(0−30 (31−182 (183−365 (366−730 n=34
days) days) days) days)
n=34 n=33 n=32 n=5
Secondary 3% 0% 0% 20% 6%
interventions (1/34) (1/5) (2/34)

No significant differences in outcomes between patients with
favourable anatomy and patients with adverse anatomy (p=ns,
Fisher’s exact test).
Abbreviations used: AAA, abdominal aortic aneurysm; CT, computerised tomography; SD, standard deviation.

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Study 3 Ameli-Renani S (2014) [Conference abstract only]
Details
Study type Retrospective case series
Country England
Recruitment period Not reported
Study population and n=48 patients with abdominal aortic aneurysm (AAA)
number
Age and sex Not reported
Patient selection criteria Not reported
Technique Nellix
Follow-up Mean 3 months (range 1−11 months)
Conflict of Not reported
interest/source of
funding
Analysis
Follow-up issues: None.
Study design issues: None.
Study population issues: The study group included 46 elective and 2 emergency repairs for ruptured aneurysms.
Other issues: None.
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Key efficacy and safety findings
Efficacy Safety
Efficacy findings from conference abstracts are not normally  No death at the latest follow-up.
considered adequate to support decisions on efficacy and are
 Complications rate: 10% (5/48)
not generally selected for presentation in the overview.
Complication Number of Outcome

patients
Stenosis/kinking 4% (2/48) Treated by extension iliac
of the distal Nellix endografts
limb
Type 2 endoleak 2% (1/48) Treated by extension iliac
from internal iliac endografts
artery
Type 1a endoleak 2% (1/48) The type 1a endoleak was
embolised with Onyx. This
was complicated by a
contrast reflux into the
proximal left Nellix stent
remedied by the placement
of a covered stent within the
proximal left Nellix stent to
isolate the displaced Onyx.
Complete 2% (1/48) This was managed
occlusion of the conservatively (no further
left Nellix stent details provided).
with preserved
perfusion of the
left leg
Partial renal 6% (3/48) No details provided. These
infarcts with adverse events were not
preserved renal included in the complications
function rate.

 Re-interventions rate; 8% (4/48)

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Efficacy
Technical success (successful delivery and deployment of the device)
A case series of 34 patients with AAA treated by endovascular aneurysm sealing
reported technical success (defined as the successful delivery and deployment of
the device) in 100% (34/34) of patients2.
Conversion to open surgical repair
The case series of 34 patients reported no conversion to open surgical repair2.
Secondary endovascular procedures of any type
The case series of 34 patients reported secondary interventions in 6% (2/34) of
patients; 1 was done within 30 days after the procedure (no further details
provided) and the other was 15 months after the procedure to treat a distal type 1
endoleak (also described in section 5)2.
Quality of life
A non-randomised prospective cohort study of patients with AAA treated by
endovascular aneurysm sealing (n=20) or open surgery (n=20) reported mean
SF-36 scores (± standard deviation) for the physical component summary
1 month after the procedure, of 47 (±3) for endovascular aneurysm sealing and
38 (±3) for open surgery (p<0.001; there was no difference between groups at
baseline). One year after the procedure, the scores were 48 (±4) for
endovascular aneurysm sealing and 42 (±3) for open surgery (p<0.001). For the
mental component summary of the SF-36 questionnaire 1 month after the
procedure, the scores were 44 (± 4) for endovascular aneurysm sealing and
37 (±3) for open surgery (p<0.001; there was no difference between groups at
baseline). One year after the procedure the scores were 40 (±4) for endovascular
aneurysm sealing and 39 (±4) for open surgery (p value not significant)1.
Safety
Death
Death was reported in 6% (2/34) of patients in a case series of 34 patients with
AAA treated by endovascular aneurysm sealing. One patient died within 30 days
after the procedure of multisystem organ failure. The authors state that this death
was not device-related “as evidenced by post-procedure CT scan and
post-mortem examination of the aneurysm and device”. The other patient died
10 months after the procedure of congestive heart failure; this patient had a
normal CT scan at 6-month follow-up2.
Endoleak
Endoleak was reported in 6% (2/34) of patients over a mean follow-up of
15 months in the case series of 34 patients. One patient had a proximal type 1
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