Comparison of the incidence of type II endoleak after
Endovascular Aneurysm Repair with
polytetrafluoroethylene (PTFE) or polyester
endografts in patients electively treated for
abdominal aortic aneurysms
Maud Kuijpers
Student number 2679073
Major Clinical major
Course code AB_1196
EC 18
Name organization Rijnstate Arnhem
Department Vascular surgery
Daily supervisor Suzanne Holewijn
VU supervisor Jan Blankensteijn
Period of internship 7 maart 2022 t/m 3 juni 2022
,Table of content
1. Abstract
2. Introduction
3. Methods
3.1 Study design
3.2 Data extraction
3.3 Study population
3.4 Endpoints
3.5 Statistical analysis
4. Results
5. Discussion
6. Reference list
7. Reflection
8. Appendices (including additional analysis)
2
,1 Abstract
Background. Endoleak type II (T2EL), characterized by collateral backflow outside the endograft in the
aneurysm sac derived from aortic branches, is the most common complication after endovascular abdominal
aneurysm repair (EVAR). The nature of graft material for abdominal aortic aneurysms (AAA) endografts may be
expanded in most cases polytetrafluoroethylene (PTFE) or polyester. IDE trials suggest that there might be a
difference in the incidence of T2EL after EVAR between PTFE and polyester endografts. Therefore, the primary
aim of this study was to evaluate the 1-year incidence of T2ELs after EVAR between PTFE and polyester
endografts in patients electively treated for an infrarenal AAA.
Methods. A single centre, retrospective observational study, was conducted between 01-01-2011 and
January 01-01- 2022. 409 patients electively treated for an infrarenal AAA were identified in an existing local
AAA database. The primary endpoint was the incidence of T2EL occurring within 12 months after the EVAR-
procedure. Secondary endpoints included the presence of procedural T2ELs (< 24 h), early T2ELs (≤ 30 days),
late T2ELs (> 30 days), persistent T2ELs (lasting longer than six months), blood vessels responsible for T2ELs and
aneurysm remodeling in time. Kaplan-meyer analysis, univariate Cox regression and multivariate backward
stepwise Cox regression and non-parametric tests were used.
Results. The study sample for follow-up information included 402 patients. Most of the procedural T2ELs
(77.9%) disappeared during the follow-up period without performing reintervention, with significantly more
disappeared procedural T2ELs in the polyester group. There was no significant difference in the incidence of
T2ELs within 12 months after EVAR between the PTFE-group and PE-group (p=0.271). The incidence of T2ELs
(without the disappearance of procedural T2ELs) was significanlty higher in the PTFE group (p=0.010). There
was no significant difference between the incidence of procedural endoleaks, early endoleaks, late endoleaks
and persistent endoleaks (p=0.493;p=0.687;p=0.687; and p=0.905, respectively). The origin blood vessel
responsible for T2EL was significantly not different between the two groups (p=0.646). The mean time to the
first diagnosed T2EL was significantly not different between the two groups (p=0.504). The mean AAA
maximum diameter has decreased after EVAR, with no significant difference between the two groups
(p=0.084). Positive predictors for T2ELs within 12 months after EVAR were higher diastolic blood pressure and
larger infrarenal neck lenght for both the T2EL incidence with and without the disappeared procedural T2ELs
included (p<0.001;p=0.007). Smoking was only a predictive factor for T2ELs when disappeared procedural
T2ELs were not included (p=0.046).
Conclusion. There was no significant difference in the incidence of T2ELs within 12 months after EVAR between
PTFE and polyester endografts in patients electively treated for an infrarenal abdominal aortic aneurysm. Most
of the procedural T2ELs disappeared during the follow-up period. When disappeared procedural T2ELs were
not included, the incidence of T2ELs was significanlty higher in the PTFE group. Only higher diastolic blood
pressure and larger infrarenal neck length contributed to predicting T2EL after EVAR within 1 year follow-up.
When disappeared procedural T2ELs were not included, smoking was also a predictive factor for T2ELs.
3
, Keywords: Abdominal aortic aneurysm: Endovascular abdominal aneurysm repair: Endoleak type II:
Polytetrafluoroethylene: Polyester: Procedural type 2 endoleak.
4
Endovascular Aneurysm Repair with
polytetrafluoroethylene (PTFE) or polyester
endografts in patients electively treated for
abdominal aortic aneurysms
Maud Kuijpers
Student number 2679073
Major Clinical major
Course code AB_1196
EC 18
Name organization Rijnstate Arnhem
Department Vascular surgery
Daily supervisor Suzanne Holewijn
VU supervisor Jan Blankensteijn
Period of internship 7 maart 2022 t/m 3 juni 2022
,Table of content
1. Abstract
2. Introduction
3. Methods
3.1 Study design
3.2 Data extraction
3.3 Study population
3.4 Endpoints
3.5 Statistical analysis
4. Results
5. Discussion
6. Reference list
7. Reflection
8. Appendices (including additional analysis)
2
,1 Abstract
Background. Endoleak type II (T2EL), characterized by collateral backflow outside the endograft in the
aneurysm sac derived from aortic branches, is the most common complication after endovascular abdominal
aneurysm repair (EVAR). The nature of graft material for abdominal aortic aneurysms (AAA) endografts may be
expanded in most cases polytetrafluoroethylene (PTFE) or polyester. IDE trials suggest that there might be a
difference in the incidence of T2EL after EVAR between PTFE and polyester endografts. Therefore, the primary
aim of this study was to evaluate the 1-year incidence of T2ELs after EVAR between PTFE and polyester
endografts in patients electively treated for an infrarenal AAA.
Methods. A single centre, retrospective observational study, was conducted between 01-01-2011 and
January 01-01- 2022. 409 patients electively treated for an infrarenal AAA were identified in an existing local
AAA database. The primary endpoint was the incidence of T2EL occurring within 12 months after the EVAR-
procedure. Secondary endpoints included the presence of procedural T2ELs (< 24 h), early T2ELs (≤ 30 days),
late T2ELs (> 30 days), persistent T2ELs (lasting longer than six months), blood vessels responsible for T2ELs and
aneurysm remodeling in time. Kaplan-meyer analysis, univariate Cox regression and multivariate backward
stepwise Cox regression and non-parametric tests were used.
Results. The study sample for follow-up information included 402 patients. Most of the procedural T2ELs
(77.9%) disappeared during the follow-up period without performing reintervention, with significantly more
disappeared procedural T2ELs in the polyester group. There was no significant difference in the incidence of
T2ELs within 12 months after EVAR between the PTFE-group and PE-group (p=0.271). The incidence of T2ELs
(without the disappearance of procedural T2ELs) was significanlty higher in the PTFE group (p=0.010). There
was no significant difference between the incidence of procedural endoleaks, early endoleaks, late endoleaks
and persistent endoleaks (p=0.493;p=0.687;p=0.687; and p=0.905, respectively). The origin blood vessel
responsible for T2EL was significantly not different between the two groups (p=0.646). The mean time to the
first diagnosed T2EL was significantly not different between the two groups (p=0.504). The mean AAA
maximum diameter has decreased after EVAR, with no significant difference between the two groups
(p=0.084). Positive predictors for T2ELs within 12 months after EVAR were higher diastolic blood pressure and
larger infrarenal neck lenght for both the T2EL incidence with and without the disappeared procedural T2ELs
included (p<0.001;p=0.007). Smoking was only a predictive factor for T2ELs when disappeared procedural
T2ELs were not included (p=0.046).
Conclusion. There was no significant difference in the incidence of T2ELs within 12 months after EVAR between
PTFE and polyester endografts in patients electively treated for an infrarenal abdominal aortic aneurysm. Most
of the procedural T2ELs disappeared during the follow-up period. When disappeared procedural T2ELs were
not included, the incidence of T2ELs was significanlty higher in the PTFE group. Only higher diastolic blood
pressure and larger infrarenal neck length contributed to predicting T2EL after EVAR within 1 year follow-up.
When disappeared procedural T2ELs were not included, smoking was also a predictive factor for T2ELs.
3
, Keywords: Abdominal aortic aneurysm: Endovascular abdominal aneurysm repair: Endoleak type II:
Polytetrafluoroethylene: Polyester: Procedural type 2 endoleak.
4
