Fenestrated Endovascular Aneurysm Repair

497 Pages·2015·14.03 MB·English

by  Jane Elizabeth Cross

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Fenestrated Endovascular
Aneurysm Repair – Validation of
Current UK Practise
MD (Res) Clinical Research
Jane Elizabeth Cross Student Number: 1047777
University College London
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I, Jane Elizabeth Cross, confirm that the work presented in this
thesis is my own. Where information has been derived from
other sources, I confirm that this has been indicated in the
thesis.
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Abstract
EVAR has revolutionised aneurysm management; level one evidence shows advantages
of endovascular repair over open repair. However, analysis of the EUROSTAR database
of >11,000 aneurysms shows that use of EVAR outside manufacturer’s instructions for
use is associated with a significant risk of aneurysm related mortality and type 1
endoleak.

Recent advances have seen the evolution of fenestrated endografts (FEVAR) to enable
endovascular repair of aneurysms with a compromised proximal neck. However, these
complex endografts are often technically difficult to insert and long term durability is
unknown. In this thesis I hypothesise that all abdominal aortic aneurysms should be
treated endovascularly and aim to determine the indications for fenestrated
endografts.

A meta-analysis found current evidence for FEVAR to be limited. A weakness in current
evidence base is lack of concurrence between definition of juxta/para and supra-renal
aneurysms leading to difficulty in comparison between series. A new classification
system of aneurysm necks based on the endograft seal zone is proposed. Further
adjuncts to complex endograft insertion are discussed including use of CO2
angiography to reduce incidence of contrast induced nephropathy and use of
temporary axillo-bifemoral grafts to reduce reperfusion injury.
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Indications for FEVAR based on current evidence are unclear and a consensus
statement to determine the indications was undertaken. An initial survey outlined
current UK practise of aneurysm management. The consensus statement using RAND
methodology determined the indications for FEVAR in approximately two thirds of all
scenarios but outlined a grey area of equipoise in almost one third of scenarios.

In conclusion, whilst most aneurysms are technically suitable for endovascular repair,
it is not possible to conclude that FEVAR is superior to open repair in the long term. A
grey area of equipoise was highlighted for the indications of EVAR; further evidence is
required to determine guidelines for patient suitability.
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Contents

Page
Part 1
1. Introduction: Background to standard EVAR 26
1.1 Level one evidence for EVAR 30
1.1a EVAR I & II Trial design 30
1.1b DREAM Trial design 30
1.1c EVAR I Early results 31
1.1d DREAM Early results 31
1.1e EVAR I midterm results 32
1.1f EVAR Trial II 33
1.1g Long term results for EVAR I Trial 34
1.1h Long term results for DREAM trial 35
1.1i Long term results for EVAR II Trial 35
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1.2 EVAR for small aneurysms 36
1.3 Summary 38

2. Endovascular Repair of Abdominal Aortic Aneurysms with Adverse Necks:
Infra-renal Sealing is not a Safe Option 41
2.1 Introduction 42
2.2 Methods 43
2.3 Results 45
2.4 Discussion 57

3. Endovascular alternatives to standard EVAR in the adverse neck 61
3.1 Fenestrated endografts 62
3.1a Indications 64
3.1b Manufacturing a "home-made" fenestrated stent graft 67
3.2 Chimney graft (aka the snorkel graft) 73
3.3 Conclusion 78
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4. A Meta-analysis of Observational Studies in Epidemiology: Fenestrated
Endovascular Aneurysm Repair 80
4.1 Introduction 81
4.2 Methods 83
4.3 Results 85
4.4 Discussion 95

5. Summary of Part 1 102
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Part 2 – FEVAR Adjuncts
6. A new classification system of AAA based upon proximal sealing zones:
Results of complex aortic stent grafting in 100 consecutive patients 110
6.1 Introduction 111
6.2 Methods 112
6.2a Patient Selection 112
6.2 b Pre-operative imaging assessment and Zone Classification 113
6.2 c Devices 114
6.2 d Methods – statistical analysis 116
6.3 Results 116
6.4 Discussion 123

7. Use of CO2 angiography for complex endovascular aneurysm repair 129
7.1 Introduction 130
7.2 Methods 132
7.3 Results 137
7.4 Discussion 140