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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 4, July/August 2021
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AFRICA
Thereafter, similar survival rates were reported. In the same
study, higher complications and interventions were reported in
the EVAR group after an eight-year follow-up period. This eight-
year follow-up period also revealed that the aneursym rupture
rate in the EVAR group was 5.4% compared to 1.4% in the open-
surgery group.
11
The EVAR group displayed higher complication
rates, secondary interventions, delayed aneursym ruptures, and
long-term aneurysm-associated mortality rates compared to the
conventional surgery groups.
10
Endoleaks are the most frequent complications of EVAR and
the frequency has been reported to range from 2.4 to 45.5%.
12
The continum of aneursym expansion, rupture development
and associated mortalities following EVAR has been reported
to be correlated with endoleaks.
13,14
Therefore, endoleaks require
a close follow up and the frequency should depend on the
endoleak type. The most common endoleaks are types I and II.
15
In one study, type I and III endoleaks were reported to have
higher sac expansion rates. They were suggested to be high-
pressure endoleaks and early medical intervention was advised.
16
On the other hand, type II and V endoleaks were considered lower
pressure and therefore less urgent for medical intervention.
17
If
aneursym volume is not increased significanlty in type II endoleaks,
they can be resolved without any medical treatment. Therefore, in
such cases a ‘wait and see’ approach has been suggested.
18
The importance of pre-operative opening of inferior
mesenteric and lumbar arteries has been documented in EVAR-
associated type II endoleaks.
2
In the current study, 3.8 and 7.6%
of the patients displayed type I and II endoleaks, respectively.
Additional interventions were performed in patients who
displayed a type I endoleak. In the follow up of patients with
type II endoleaks, abnormal sac expansion was not observed,
therefore additional interventions were not performed. The
reduced endoleak rates in the present study compared to the
other published studies in the literaure could be associated with
the short follow-up period.
In our study, the impact of the device used on the observed
differences in endoleak, graft migration and sac regression
following EVAR was also investigated and a potential impact
of the device was found.
19
However, opposite results stating no
effect of the device has also been reported.
1
The impact of three
different devices was investigated on the volumetric regression
following EVAR and no significant difference was found.
However, irregularities in the number of devices distributed may
have impacted on the current results.
The correlation between pre-operative thrombus load and
sac regression has been investigated and controversial results
have been reported. Some studies report an increased sac
expansion with lower thrombus load.
9
Slower regression and
higher intervention rates have also been reported in cases of
elevated thrombus load.
20
However, there are some studies that
do not suggest any association between thrombus load and sac
regression.
21
In the present study, volumetric regression of TAV
was significantly higher in all three postoperative periods, with a
higher thrombus load.
It is well known that development of an aneursym is a chronic
condition and may continue after EVAR. Therefore, CTA scans
should be performed during the early and late postoperative
period in order to determine expansion and the elimination of
potential endoleaks. Lifetime CTA monitoring however is a
disadvantage.
22
The results of our study suggest the use of three-
dimensional reconstructive volumetric measurements that show
all surfaces of the aneurysm instead of using two-dimensional
longitudinal sections that only allow assessment of diameter.
The main limitations of our study were the retrospective
nature of data collection, the relatively small sample size, and lack
of long-term follow up. Other limiting factors that could have
affected regression or enlargement and were largely unknown
were patient-related factors, such as smoking, hypertension
and medication used. Also the number of CTA images done
decreased, especially by the 24th month postoperatively.
Conclusion
Even though mean TAV displayed volumetric regression for
the first 12 months, the re-start of expansion at 24 months
supports the long-term doubts about EVAR. PLV measurements
demonstrated that six-, 12- and 24-month measurements did
not show significant differences after the placement of a stent.
However, increased expansion of TAV while PLV were not
significantly different at 24 months suggests pathological
processes had continued outside the stent graft. The most
regression of the aneurysm sac was detected in the distal portion,
followed by the proximal and then the middle sections. Future
long-term studies are required to determine when sac expansion
will reach the pre-operative state and what course this expansion
will take in the period after 24 months.
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