Endovascular aneurysm repair: prevention and treatment of complications
Goudeketting, Seline
DOI:
10.33612/diss.98524202
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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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ENDOVASCULAR ANEURYSM REPAIR
Prevention and treatment of complications
ISBN: 978-94-034-1813-1 (electronic version) ISBN: 978-94-034-1812-4 (printed book) Cover design: Tim de Roos
Lay-out: Ilse Modder, www.ilsemodder.nl
Printed by: Gildeprint - Enschede, www.gildeprint.nl Copyright © S.R. Goudeketting 2019
All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, without prior permission of the publisher and copyright owner, or where appropriate, the publisher of the articles.
The author gratefully acknowledges financial support of this thesis by: St. Antonius Ziekenhuis Nieuwegein, Faculteit Medische Wetenschappen Universitair Medisch Centrum Groningen, Rijksuniversiteit Groningen, Chipsoft and Stichting Lijf en Leven.
Endovascular aneurysm repair:
prevention and treatment of complications
PhD thesis
to obtain the degree of PhD at the University of Groningen
on the authority of the Rector Magnificus Prof. C. Wijmenga
and in accordance with the decision by the College of Deans. This thesis will be defended in public on Wednesday 23 October 2019 at 16:15 hours
by
Seline Rachelle Goudeketting
born on 17 July 1991 in Zwolle
Prof. C.H. Slump
Assessment committee Prof. J.A.M. Zeebregts Prof. W. Wisselink Prof. J.A. Reekers
Chapter 1 General introduction and outline of the thesis
PART I Can new imaging modalities help prevent complications in the treatment of aortoiliac disease?
Chapter 2 Pros and cons of 3D image fusion in endovascular aortic repair: a systematic review and meta-analysis
Chapter 3 The use of 3D image fusion for percutaneous transluminal angioplasty and stenting of iliac artery obstructions: validation of the technique and systematic review of literature
Chapter 4 Changes in apposition of endograft limbs in the iliac arteries post-EVAR. Determination with new CT-applied software
PART II Outcomes of endovascular AAA repair in complex anatomies
Chapter 5 Influence of aortic neck characteristics on successful aortic wall penetration of EndoAnchors in therapeutic use during endovascular aneurysm repair
Chapter 6 Analysis of the position of EndoAnchor implants in therapeutic use during endovascular aneurysm repair Chapter 7 The effect of different EndoAnchor configurations on
aortic endograft displacement resistance: an experimental study
Chapter 8 Midterm single-centre results of endovascular abdominal aortic aneurysm repair with additional EndoAnchors
11 28 31 51 71 90 93 113 135 155
Chapter 9 Systematic review and meta-analysis of elective and urgent late open conversion after failed endovascular aneurysm repair
Chapter 10 Summary, general discussion and future perspectives Nederlandse samenvatting, algemene discussie en toekomstvisie
Chapter 11 List of abbreviations
Graduation committee
Co-authors and affiliations Dankwoord List of publications Curriculum Vitae 177 211 224 239 243 244 246 250 252
General Introduction
and Outline of the Thesis
INTRODUCTION
Abdominal aortic aneurysm
An abdominal aortic aneurysm (AAA) is defined as a 50% increase in aortic diameter compared with the healthy native aortic diameter or an absolute diameter larger than 3 cm.1 The prevalence of AAA is estimated to be up to 14.2% in men and 6.2% in women,
and risk factors include advanced age, male sex, family history, smoking, diabetes mellitus, atherosclerosis, and hypertension.1–5 Three main processes are involved in the
process of dilatation, which are inflammation, upregulation of proteolytic pathways, and smooth muscle cell apoptosis. Inflammation is associated with the production of reactive oxygen species and oxidative stress, which induces vascular smooth muscle apoptosis and promotes the proteolytic pathway that results in degradation of extracellular matrix proteins in the aortic wall. This, in turn, decreases the elastin concentration and increases the production of disordered collagen, thereby further weakening the aortic wall. Over time, the combination of elastin degradation and continuous hemodynamic load results in dilatation of the aortic wall.1,4 Atherosclerosis
can develop as a consequence of the changes in luminal flow, which can result in chronic inflammation and may accelerate the breakdown of collagen and elastin.1,6
Aneurysms are known to continue to grow over time. This increases the risk of rupture, which has a reported mortality rate of up to 85%.1,7 Growth rates of 0.2
to 0.3 cm/year have been reported for AAAs between 3 cm and 5.5 cm, but larger aneurysms tend to expand faster compared with smaller aneurysms.3,8 Risk of rupture
is sex-dependent, and despite the higher prevalence of AAA in men, the rupture rate is higher in women.5,8 Elective treatment for AAA is indicated when the risk of rupture
is larger than the risk of the intervention. The 2018 Society for Vascular Surgery guidelines recommend elective repair for patients at low or acceptable surgical risk with aneurysms of >5.5 cm for men and >5 cm for women. AAAs with a growth rate of more than 1 cm/year should be repaired at a smaller diameter.3,8 In case of a high
operative risk, the AAA diameter threshold of when to treat may be diameters between 6 cm and 7 cm. The decision whether to intervene is not only dependent on aneurysm size and risk of rupture, but comorbidities, physical status, and life expectancy should also be taken into account.8 Thus, the treatment strategy should be defined for each
individual patient and aortic anatomy.
Treatment of AAAs
Treatment options for AAA are open surgery or endovascular repair. Open surgical repair has been practiced since its first description in 1952 and has been refined ever since.9 The procedure requires laparotomy, clamping of the aorta, aortotomy to
remove thrombus and debris from within, and subsequently, insertion of a prosthetic graft. Even in patients fit for surgery, there is a significant risk of complications: reported mortality was up to 4.2% and postoperative complications occurred in up to 13%.10,11
Volodos et al.12 first described the endovascular aneurysm repair (EVAR) technique
in 1986 as an alternative treatment approach for AAAs. During EVAR, arterial access is achieved through the common femoral arteries. An introduction sheath allows insertion of guidewires, over which catheters and the endograft’s main body and limbs can be advanced.13,14 The main body needs an oversizing of 15% to 20% compared
with the diameter of the infrarenal neck to create a radial force that provides fixation and withstands drag forces.15 In addition, hooks, barbs, and/or suprarenal bare-metal
stents are incorporated to enhance fixation.
For infrarenal AAAs, the self-expandable endograft is positioned just below the lowest (most distal) renal artery orifice in the infrarenal aortic neck. The contralateral iliac limb is inserted after main body deployment, and if adequate proximal and distal seal is achieved, the aneurysm will be successfully excluded from the blood flow.14,16
Approximately 30% of patients have AAAs with unsuitable proximal neck anatomy for a standard EVAR procedure. Hostile aortic neck anatomy includes short neck length (<10-15 mm), large aortic neck diameter (>30 mm), large infrarenal angulation (>60°), reversed taper, and/or large thrombus or calcium load. This may hamper the sealing and fixation of the endograft within the aortic neck.8,17–22 To circumvent these
problems and to treat juxtarenal and suprarenal aneurysms, fenestrated, branched, or chimney EVAR procedures (F/B/ch-EVAR) can be performed. These procedures are generally more complex, because additional stents are deployed to maintain the blood flow to the renal and/or visceral arteries.22,23
Compared with open repair, EVAR significantly reduces short-term cardiac and pulmonary complications and demonstrates lower early morbidity and mortality rates.8,24 This latter is especially beneficial in patients with high surgical risk. EVAR is also
associated with shorter procedure and recovery times, reduced hospital and intensive care unit lengths of stay, and reduced blood loss.8,10,25 Reports on renal complications
vary in literature, but appear to be dependent on follow-up duration.26Acute renal
insufficiency has shown lower incidences after EVAR (2%-19%) compared with open repair (11%-27%).27,28 At 3 years’ follow-up, however, increased renal impairment
has been observed after EVAR (between 25% and 36%) than after open repair (up to 19%).27–30 The steady decline in renal function after EVAR can be attributed to the high
contrast volumes required for continued postoperative computed tomography (CT) angiography (CTA) surveillance.31 Nevertheless, the rates of renal failure requiring
dialysis are comparable to open repair procedures, ranging between 0.5% and
2%.28,32 On long-term follow-up, open aneurysm repair procedures demonstrate
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higher freedom from reinterventions, largely because of the number of graft-related complications with EVAR.11,33,34
Whether EVAR is more cost-effective than open surgical repair remains unclear because of the many factors involved, including the preoperative imaging, implants, hospitalization duration, treatment of complications at the time of the initial procedure or during follow-up, and long-term imaging follow-up.8 Currently, EVAR
is the preferred treatment strategy, largely due to its minimally invasive character and lower morbidity and postoperative mortality in young patients with low operative risk. However, FEVAR or open surgical repair should be performed in patients with unfit anatomy for standard EVAR.
Role of imaging in EVAR
Preoperative assessment
CTA is routinely performed during the preprocedural workup to visualize the aortoiliac trajectory. The protocol typically includes a multiphase acquisition: a noncontrast, arterial, and/or delayed-phase examination. The noncontrast CT acquisition is useful in differentiating calcifications. For the arterial phase, iodinated contrast medium is administered intravenously, and the acquisition is performed using bolus triggering. Ideally, slices are reconstructed to 1.0 mm to 1.5 mm. Delayed images can be acquired approximately 2 minutes after the contrast injection and are useful to assess slow endoleaks.35 Drawbacks of CTA are the use of radiation and iodinated contrast
material that may induce nephrotoxicity.28 Contrast-enhanced magnetic resonance
angiography (MRA) can be performed in patients who cannot receive iodinated contrast. MRA does not use radiation, but is more time consuming and expensive than CTA and is also not suitable for patients with metal implants.23,36 Even though both
imaging techniques can be used for preoperative EVAR planning, CTA is considered the gold standard and the preferred imaging modality because it is readily available and fast.
Intraoperative guidance
Endovascular procedures are performed under fluoroscopy guidance and rely on the use of iodinated contrast media and ionizing radiation. By use of digital subtraction angiographies (DSAs) the location of the origins of the renal and internal iliac arteries can be visualized. DSAs can also visualize possible complications after endograft deployment.37,38 Because of the potentially nephrotoxic effects of iodinated contrast
and carcinogenic factors of radiation, it is highly relevant to reduce the number of imaging series. Patients with pre-existing renal impairment are especially at greater risk for renal complications during follow-up.27,28 Moreover, reducing radiation
exposure and procedure time may be beneficial to both patients and specialists.39 The
number of imaging series used greatly depends on the procedure complexity: more complex procedures proportionally increase the amount of administered contrast, radiation dose, and procedure time; for example, the radiation doses for complex EVAR procedures can be twice those of standard EVAR procedures.40
Preprocedural imaging holds valuable information that is used for planning the procedures and sizing the endografts but can also be used during the endovascular interventions. New available three-dimensional (3D) image guidance tools allow for intraoperative use of preoperative CTA for continuous fusion guidance during these interventions. After rigid registration of preoperative imaging to an intraoperatively acquired cone-beam CT scan, the CTA images are overlaid on live fluoroscopy. Dijkstra et al.41 were the first to report the use of this 3D image fusion technique in
patients undergoing FEVAR. The technique demonstrated reduction in contrast and radiation dose for EVAR and more complex EVAR procedures such as branched or fenestrated thoracic aortic aneurysm repair.41–44 Introduction of stiff guidewires and
delivery systems during EVAR may influence the accuracy of the fusion images caused by deformation of iliac arteries.45,46 To fully rely on the use of the 3D image fusion
technique and minimize contrast and fluoroscopy use, accurate registration of the images is of utmost importance.
Postoperative EVAR surveillance and complications
Despite the improvements in endograft fixation (e.g., suprarenal fixation and anchoring hooks and pins), complications still occur in the long-term after EVAR. Follow-up imaging is therefore necessary to assess for late complications. Imaging is routinely performed by CTA at 1 and 12 months postoperatively, and in case of no complications, annual duplex ultrasound imaging is used thereafter.3,8 Some complications are similar
to those observed after open repair procedures, such as graft infection, aortoenteric fistulas, graft occlusion, or thrombosis.25 Other complications are more EVAR specific
and include the occurrence of endoleaks (i.e., persistent blood flow into the aneurysm sac) and migration of the implanted device.8,16
Type I endoleaks occur due to incomplete sealing at the proximal (type IA) or distal (type IB) landing zones.8,16 Type II endoleaks arise from branch vessels that feed
the aneurysm sac through retrograde flow, which can lead to sac enlargement. Type III endoleaks are usually structural failures (holes or defects) or separations of the endograft components. Type IV endoleaks represent porous endograft material that will spontaneously seal, and treatment is not required. Finally, type V endoleaks (or endotension) are described as an enlarging aneurysm sac without visible endoleak.8
Repair of type I and III endoleaks is advised when detected, because they can lead
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to repressurization of the aneurysm, sac expansion, and ultimately, rupture.16,24,47–51
The management of type II endoleaks continues to be debated: treatment is generally recommended for leaks with sac expansion of >1 cm, whereas surveillance suffices when no sac enlargement is observed. Endotension management should be individualized to the patient and can entail surveillance, relining of the endograft, or explantation.8
Migration is defined as endograft displacement by more than 5 to 10 mm, which is often caused by dilatation of the aortic neck.16 If left untreated, migration may lead to
late type I endoleaks and an increased risk of rupture.16,24,47–51 Secondary interventions
after EVAR, which have been reported to have a rate as high as 20%, are ideally performed endovascularly.52–54
Proximal neck–related complications
Reinterventions for type IA endoleaks and migration are required in up to 3.0% and 5.1% of the patients, respectively.34,55–58 A significantly higher occurrence of type
IA endoleaks is observed in patients with hostile proximal neck anatomy.19 Initial
treatment for type IA endoleaks is balloon angioplasty to remodel the proximal part of the endograft and promote apposition. In case of undersized, maldeployed, or migrated endografts, covered extension cuffs can be deployed to overcome the seal failures and create a new seal length of at least 15 mm. If this can only be achieved by extension superior to the renal arteries, FEVAR cuffs are the preferred treatment option to maintain renal blood flow. The Heli-FX EndoAnchor system (Medtronic Vascular, Santa Rosa, CA, USA) can also be used to prevent further migration of the endograft or treat type IA endoleaks by attaching the endograft to the aortic wall. Alternatively, coil or Onyx (ev3, Irvine, CA, USA) embolization can be performed to treat an endoleak. These can be useful in case of short infrarenal necks or when the aforementioned techniques are insufficient in treating the complication, and patients are not good candidates for open conversion. Lastly, when FEVAR cuffs cannot be deployed and there are no other endovascular options, bare-metal stents (e.g., Palmaz stents [Cordis Corporation, a Cardinal Health company, Milpitas, CA, USA] or AndraStent [Andramed, Reutlingen, Germany]) can be deployed to achieve adequate seal.20,59
EndoAnchors
EndoAnchors are developed to improve seal and increase the migration resistance of endografts in the aortic neck. They can be used prophylactically to enhance proximal fixation and seal60–62 but are also commonly deployed in a therapeutic
setting to resolve type IA endoleaks and to prevent further endograft migration.63,64
Four or six EndoAnchors should be circumferentially deployed, depending on aortic
neck diameter (≤29 mm or >29 mm), in which case the migration resistance can approximate that of a surgical hand-sewn anastomosis.63,65 Current reports on the
use of EndoAnchors mainly come from the Aneurysm Treatment Using the Heli-FX Aortic Securement System Global Registry (ANCHOR; NCT01534819) that assesses worldwide use of EndoAnchors in patients with unfavorable aortic neck anatomy. The registry consists of a primary (prophylactic and therapeutic treatment for acute type IA endoleaks) and revision arm (therapeutic treatment for type IA endoleaks and/or migration during follow-up). Results demonstrated high technical success rates in the treatment of acute and late type IA endoleaks.60 In addition, prophylactic use of
EndoAnchors resulted in a significant sac regression 2 years after EVAR compared with standard EVAR without EndoAnchors.66
To achieve fixation and resolve type IA endoleaks, EndoAnchors should be circumferentially and successfully deployed into the aortic wall (i.e., penetration of at least 2 mm). At 1-year follow-up of the ANCHOR study, 4% to 8% of patients demonstrated persistent or renewed type IA endoleaks.64,67 Reasons for type IA
endoleak after EndoAnchor treatment need to be investigated to improve outcomes after the EndoAnchor implantation procedure. Individual analysis of EndoAnchor penetration depths, angles, and circumferential distribution will give insight in the association between EndoAnchor implantation and successful treatment of type IA endoleaks.
Even though circumferential distribution is recommended, EndoAnchors are frequently used in a targeted manner when treating type IA endoleaks. The EndoAnchors are often only deployed in or near the endoleak and not along the entire circumference, whereas during prophylactic use, they are more frequently deployed circumferentially. The effect on migration resistance of other than circumferential distributions needs to be analyzed to understand the possible long-term consequences of these other configurations.
Distal seal complications
Even though less attention has been paid to the distal endograft fixation, sufficient distal seal is important to prevent distal complications. Type IB endoleaks can develop due to dilatation of the common iliac artery or lack of radial force of the endograft limb within the vessel, which may lead to endograft limb retraction.68,69 Reintervention
for type IB endoleaks is required in up to 2.3% of post-EVAR patients.34,55–58 Endograft
limb failure can be treated by a branched iliac device or hypogastric embolization and limb extension into the external iliac artery. Alternatively, an open reconstruction can be performed.20
Because of the dynamic surroundings of the endograft, subtle changes in the
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position of the endograft may take place before migration or endoleaks occur.24 Vascular
Imaging Analysis (VIA) prototype software (Endovascular Diagnostics BV, Utrecht, The Netherlands) was developed to detect these subtle changes in the proximal neck.70
The VIA prototype software uses 3D coordinates acquired from CTA images to define infrarenal aortic neck characteristics and endograft position and apposition.71 By
analyzing CT scans during follow-up and visualizing the position and apposition of the endograft, the occurrence of proximal neck-related complications can be predicted.70
This same software may be able to detect subtle changes in position and apposition of the endograft limbs, which can provide information to predict distal complications. In case of complications requiring treatment, these are preferably performed electively. Thus, early detection of changes in endograft limb position that may be indications for future complications is important to prevent the need for urgent reinterventions.
Open conversion
When further endovascular salvage procedures may be unsafe or unfeasible, open conversion has to be considered.8 Explantation of an endograft may be technically
challenging, and the risk associated with these procedures is considerable. Mortality rates of 3% to 10% have been reported.72 The number of early and late complications
after EVAR may increase, because physicians seem to be pushing the boundaries by treating more complex cases. Consequently, this may also increase the rate of late open conversion after EVAR. It is important to understand the risks associated with late open conversions in an elective and urgent setting to come to a patient-tailored decision on when to perform the conversion.
AIMS AND OUTLINE OF THE THESIS
This thesis is divided into two parts. The first presents and investigates whether new imaging modalities can help to prevent complications in the treatment of obstructive and aneurysmatic aortoiliac disease, and the second part is focused on outcomes of EVAR in complex anatomies.
Part I offers insights on new imaging modalities to help prevent and detect complications during and after treatment of aortoiliac obstructions and aneurysms. The two objectives of the first part of this thesis are to
•
investigate the potential and accuracy of fusion imaging during endovascularaortoiliac interventions for obstructive and aneurysmal disease, and
1
•
validate the VIA prototype software for the analysis of the position and apposition of endograft limbs during EVAR follow-up.More complex EVAR procedures will demand an increase of radiation exposure and contrast use, and innovations in intraoperative imaging are being sought to minimize this. Chapters 2 and 3 report on the use of a 3D image fusion technique in endovascular procedures. For the fusion imaging to be fully incorporated in clinical practice, it is important to investigate its registration accuracy and understand the benefits of intraoperative use during endovascular procedures. Chapter 2 therefore investigates the registration accuracy of the use of this multimodal image fusion technique in endovascular obstructive iliac artery interventions and the effect of the insertion of stiff guidewires on fusion accuracy. Chapter 3 analyses the potential of the 3D image fusion technique in EVAR procedures to reduce the amount of contrast media used, radiation dose, procedure time, and fluoroscopy time.
Postprocedural imaging is regularly performed after EVAR to assess for complications; however, small positional changes in endograft limbs may be missed on regular CT scans. The VIA prototype software has demonstrated that it can accurately visualize and predict proximal neck–related complications. To prevent late distal seal complications, Chapter 4 validates the VIA software to determine endograft limb position and apposition in iliac arteries during follow-up after EVAR.
Part II is subdivided into two sections. The first section is specifically focused on the analyses of the position of individual EndoAnchors and subsequently investigates the effect of EndoAnchors on resolving type IA endoleaks and providing fixation and seal. The second section focuses on the outcomes of EVAR and late conversions after EVAR in patients with complex anatomies.
The objectives of Part IIa are to:
•
demonstrate a novel method for analysis of aortic wall penetration and positionof individual EndoAnchors and its effect on resolving type IA endoleaks, and
•
investigate distribution patterns along the aortic neck circumference toimprove EndoAnchor use in preventing endograft migration.
To treat or prevent type IA endoleaks and migration by use of EndoAnchors, successful circumferential deployment is recommended. Yet, complications still develop or persist after EndoAnchor use. The influence of anatomic characteristics on successful deployment of EndoAnchors needs to be reviewed to understand the occurrence
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of proximal neck–related events. Therefore, Chapter 5 reports a novel method to quantify EndoAnchor penetration depths into the aortic wall. All EndoAnchors from a cohort of ANCHOR patients receiving therapeutic EndoAnchors for type IA endoleaks are investigated and classified into one of three categories: good, borderline, or no penetration. Predictors of successful EndoAnchor penetration are assessed, and the predictors for persistent type IA endoleaks after EndoAnchor use are established. EndoAnchors should be deployed within the seal zone, and calcified regions or areas with thrombus >2 mm thickness should be avoided. Because penetration for nearly 47% of EndoAnchors was inadequate, Chapter 6 investigates EndoAnchor deployment beyond recommended use. EndoAnchor implantation above the endograft fabric or within gaps of >2 mm between the endograft and aortic wall (e.g., below the aortic neck, large endoleaks, or within thick thrombus) is defined as beyond recommended use. In addition, the individual EndoAnchor analyses of the previous study are expanded by assessment of deployment angles, distribution, and location along the circumference of the aortic neck. This will increase the understanding of endoleak persistence after EndoAnchor deployment.
A large variety in EndoAnchor distribution patterns along the aortic circumference was observed in the investigated ANCHOR cohort, even though a circumferential distribution is desired. An understanding of the consequence of these other distributions is important, because they may result in late complications. In Chapter 7, an experimental model is developed to investigate the effect of different EndoAnchor configurations on displacement resistance of the endograft. This study defines displacement of the proximal endograft when part of the endograft migrates by 3 mm and illustrates the importance of different EndoAnchor distributions on proximal fixation.
The objectives of Part IIb are to:
•
discuss the long-term outcomes of EVAR with EndoAnchors, and•
review the outcomes of late open conversions after failed EVAR.Current reports on the outcomes after EndoAnchor use are mainly from the multicenter ANCHOR database consisting of many different centers and user experiences. In addition, EndoAnchors can reduce gutter formation after ch-EVAR procedures, but outcomes after these procedures with the addition of EndoAnchors are limited. Therefore, Chapter 8 reports the midterm clinical outcomes of patients treated by (ch-)EVAR procedures with additional EndoAnchors in a single center. End points include the occurrence of type IA endoleaks, need for proximal neck–related reinterventions, and aneurysm-related mortality.
Late conversion can be considered when endovascular salvage procedures prove insufficient to treat complications after EVAR. Chapter 9 provides a comprehensive systematic review of the literature investigating the 30-day mortality rates for urgent and elective late open conversions. The outcomes can be used to accurately inform the patients about the risk associated with late open conversion after primary EVAR. Finally, Chapter 10 concludes this thesis with a summary, general discussion, and future perspectives.
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30. Greenhalgh R, Brown L, Kwong G, et al. Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomized controlled trial. Lancet. 2004;364:843-848.
31. Nijhof WH, Baltussen EJM, Kant IMJ, et al. Low-dose CT angiography of the abdominal aorta and reduced contrast medium volume : Assessment of image quality and radiation dose. Clin Radiol. 2015:1-10. 32. Wald R, Waikar SS, Liangos O, et al. Acute renal failure after endovascular vs open repair of abdominal
aortic aneurysm. 2002.
33. van Schaik TG, Yeung KK, Verhagen HJ, et al. Long-term survival and secondary procedures after open or endovascular repair of abdominal aortic aneurysms. J Vasc Surg. 2017;66(5):1379-1389.
34. De Bruin JL, Baas AF, Buth J, et al. Long-term outcome of open or endovascular repair of abdominal aortic aneurysm. N Engl J Med. 2010;362(20):1881-1889.
35. Baliyan V, Verdini D, Meyersohn NM. Noninvasive aortic imaging. Cardiovasc Diagn Ther. 2018;8(I):3-18. 36. Kicska G, Litt H. Preprocedural planning for endovascular stent-graft placement. Semin Interv Radiol.
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2009;26(1):44-55.
37. Bekken J, Jongsma H, Ayez N, et al. Angioplasty versus stenting for iliac artery lesions (Review). Cochrane Database Syst Rev. 2015;(5):1-29.
38. P. Törnqvist, N.V. Dias TR. Optimizing imaging for aortic repair. J Cardiovasc Surg (Torino). 2015;56:189-195.
39. Van Den Berg JC. Update on New Tools for Three-dimensional Navigation in Endovascular Procedures. Aorta. 2014;2:279-285.
40. De Ruiter QMB, Reitsma JB, Moll FL, et al. Meta-analysis of Cumulative Radiation Duration and Dose during EVAR Using Mobile, Fixed, or Fixed/3D Fusion C-Arms. J Endovasc Ther. 2016;23(6):944-956. 41. Dijkstra ML, Eagleton MJ, Greenberg RK, et al. Intraoperative C-arm cone-beam computed tomography
in fenestrated/branched aortic endografting. J Vasc Surg. 2011;53:583-590.
42. Dias NV, Billberg H, Sonesson B, et al. The effects of combining fusion imaging, low-frequency pulsed fluoroscopy, and low-concentration contrast agent during endovascular aneurysm repair. J Vasc Surg. 2015;63:1147-1155.
43. Hertault A, Maurel B, Sobocinski J, et al. Impact of hybrid rooms with image fusion on radiation exposure during endovascular aortic repair. Eur J Vasc Endovasc Surg. 2014;48:382-390.
44. Kaladji A, Dumenil A, Mahé G, et al. Safety and accuracy of endovascular aneurysm repair without pre-operative and intra-pre-operative contrast agent. Eur J Vasc Endovasc Surg. 2015;49:255-261.
45. Kaladji A, Dumenil A, Castro M, et al. Prediction of deformations during endovascular aortic aneurysm repair using finite element simulation. Comput Med Imaging Graph. 2013;37(2):142-149.
46. Schulz CJ, Schmitt M, Böckler D, et al. Fusion Imaging to Support Endovascular Aneurysm Repair Using 3D-3D Registration. J Endovasc Ther. 2016;23(5):791-799.
47. Powell JT, Sweeting MJ, Ulug P, et al. Meta-analysis of individual-patient data from EVAR-1, DREAM, OVER and ACE trials comparing outcomes of endovascular or open repair for abdominal aortic aneurysm over 5 years. Br J Surg. 2017;104(3):166-178.
48. Schlösser FJV, Gusberg RJ, Dardik A, et al. Aneurysm Rupture after EVAR: Can the Ultimate Failure be Predicted? Eur J Vasc Endovasc Surg. 2009;37(1):15-22.
49. Fransen GAJ, Vallabhaneni SR, van Marrewijk CJ, et al. Rupture of infra-renal aortic aneurysm after endovascular repair: A series from EUROSTAR registry. Eur J Vasc Endovasc Surg. 2003;26(5):487-493. 50. Filis KA, Galyfos G, Sigala F, et al. Proximal Aortic Neck Progression: Before and After Abdominal Aortic
Aneurysm Treatment. Front Surg. 2017;4(May):1-6.
51. Spanos K, Karathanos C, Athanasoulas A, et al. Systematic review of follow-up compliance after endovascular abdominal aortic aneurysm repair. J Cardiovasc Surg (Torino). 2018;59(4):611-618. 52. Conrad MF, Adams AB, Guest JM, et al. Secondary intervention after endovascular abdominal aortic
aneurysm repair. Ann Surg. 2009;250(3):383-389.
53. Mehta M, Sternbach Y, Taggert JB, et al. Long-term outcomes of secondary procedures after endovascular aneurysm repair. J Vasc Surg. 2010;52(6):1442-1448.
54. Stather PW, Sidloff D, Dattani N, et al. Systematic review and meta-analysis of the early and late outcomes
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of open and endovascular repair of abdominal aortic aneurysm. Br J Surg. 2013;100(7):863-872. 55. Hobo R, Buth J. Secondary interventions following endovascular repair of abdominal aortic aneurysm.
Diagnostic Interv Radiol. 2006;12(2):99-104.
56. Brown LC, Powell JT, Thompson SG, et al. The UK endovascular aneurysm repair (EVAR) trials: Randomised trials of EVAR versus standard therapy. Health Technol Assess (Rockv). 2012;16(9).
57. Leurs LJ, Kievit J, Dagnelie PC. Influence of infrarenal neck length on outcome of endovascular abdominal aortic aneurysm repair. J endovasc Ther. 2006;13:640-648.
58. Zhou W, Blay E, Varu V, et al. Outcome and clinical significance of delayed endoleaks after endovascular aneurysm repair. J Vasc Surg. 2014;59(4):915-920.
59. Faries PL, Cadot H, Agarwal G, et al. Management of endoleak after endovascular aneurysm repair: Cuffs, coils, and conversion. J Vasc Surg. 2003;37(6):1155-1161.
60. Jordan WD, de Vries JPPM, Ouriel K, et al. Midterm Outcome of EndoAnchors for the Prevention of Endoleak and Stent-Graft Migration in Patients With Challenging Proximal Aortic Neck Anatomy. J Endovasc Ther. 2015;22(2):163-170.
61. Perdikides T, Melas N, Lagios K, et al. Primary endoanchoring in the endovascular repair of abdominal aortic aneurysms with an unfavorable neck. J Endovasc Ther. 2012;19(6):707-715.
62. De Vries JPPM, van de Pavoordt HDWM, Jordan JR WD. Rationale of EndoAnchors in abdominal aortic aneurysms with short or angulated necks. J Cardiovasc Surg. 2014;55:103-107.
63. Avci M, Vos JA, Kolvenbach RR, et al. The use of endoanchors in repair EVAR cases to improve proximal endograft fixation. J Cardiovasc Surg (Torino). 2012;53(4):419-426.
64. Jordan WD, Mehta M, Varnagy D, et al. Results of the ANCHOR prospective, multicenter registry of EndoAnchors for type Ia endoleaks and endograft migration in patients with challenging anatomy. J Vasc Surg. 2014;60(4):885-892.e2.
65. Melas N, Perdikides T, Saratzis A, et al. Helical EndoStaples enhance endograft fixation in an experimental model using human cadaveric aortas. J Vasc Surg. 2012;55(6):1726-1733.
66. Muhs BE, Jordan W, Ouriel K, et al. Matched cohort comparison of endovascular abdominal aortic aneurysm repair with and without EndoAnchors. J Vasc Surg. 2017:1-9.
67. Jordan WD, Mehta M, Ouriel K, et al. One-year results of the ANCHOR trial of EndoAnchors for the prevention and treatment of aortic neck complications after endovascular aneurysm repair. Vascular. 2016;24(2):177-186.
68. Arko FR, Heikkinen M, Lee ES, et al. Iliac fixation length and resistance to in-vivo stent-graft displacement. J Vasc Surg. 2005;41(4):664-671.
69. Bastos Gonçalves F, Oliveira NF, Josee van Rijn M, et al. Iliac Seal Zone Dynamics and Clinical Consequences After Endovascular Aneurysm Repair. Eur J Vasc Endovasc Surg. 2017;53(2):185-192.
70. Schuurmann RCL, van Noort K, Overeem SP, et al. Determination of Endograft Apposition, Position, and Expansion in the Aortic Neck Predicts Type IA Endoleak and Migration After Endovascular Aneurysm Repair. J Endovasc Ther. 2018;25(3):366-375
71. Van Noort K, Schuurmann RCL, Slump CH, et al. A new method for precise determination of endograft
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position and apposition in the aortic neck after endovascular aortic aneurysm repair. J Cardiovasc Surg (Torino). 2016;57(5):737-746.
72. Scali ST, Beck AW, Chang CK, et al. Defining risk and identifying predictors of mortality for open conversion after endovascular aortic aneurysm repair. J Vasc Surg. 2016;63(4):873-881e1.
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Can New Imaging Modalities
Help Prevent Complications
in the Treatment of
Aortoiliac Disease?
The Use of 3D Image Fusion
for Percutaneous Transluminal
Angioplasty and Stenting of
Iliac Artery Obstructions:
Validation of the Technique and
Systematic Review of Literature
Seline R. Goudeketting* Stefan G. H. Heinen* Daniel A. F. van den Heuvel
Marco J. van Strijen Michiel W. de Haan Cornelis H. Slump Jean-Paul P.M. de Vries *Both authors contributed equally J Cardiovasc Surg (Torino). 2018 Feb;59(1):26-36
2
ABSTRACT
Background: The effect of the insertion of guidewires and catheters on fusion accuracy of the three-dimensional (3D) image fusion technique during iliac percutaneous transluminal angioplasty (PTA) procedures has not yet been investigated.
Methods: Technical validation of the 3D fusion technique was evaluated in 11 patients with common and/or external iliac artery lesions. A preprocedural contrast-enhanced magnetic resonance angiogram (CE-MRA) was segmented and manually registered to a cone-beam computed tomography image created at the beginning of the procedure for each patient. The treating physician visually scored the fusion accuracy (i.e., accurate [<2 mm], mismatch [2–5 mm], or inaccurate [>5 mm]) of the entire vasculature of the overlay with respect to the digital subtraction angiography (DSA) directly after the first obtained DSA. Contours of the vasculature of the fusion images and DSAs were drawn after the procedure. The cranial-caudal, lateral-medial, and absolute displacement were calculated between the vessel centerlines. To determine the influence of the catheters, displacement of the catheterized iliac trajectories were compared with the noncatheterized trajectories. Electronic databases were systematically searched for available literature published between January 2010 till August 2017.
Results: The mean registration error for all iliac trajectories (N=20) was small (4.0 ± 2.5 mm). No significant difference in fusion displacement was observed between catheterized (n = 11) and noncatheterized (n = 9) iliac arteries. The systematic literature search yielded 2 manuscripts with a total of 22 patients. The methodological quality of these studies was poor (≤11 MINORS score), mainly due to a lack of a control group. Conclusions: Accurate image fusion based on preprocedural CE-MRA is possible and could potentially be of help in iliac PTA procedures. The flexible guidewires and angiographic catheters, routinely used during endovascular procedures of iliac arteries, did not cause significant displacement that influenced the image fusion. Current literature on 3D image fusion in iliac PTA procedures is of limited methodological quality.
INTRODUCTION
Peripheral artery disease (PAD) of the lower extremities affects between 15% and 20% of people aged older than 70 years.1 The iliac artery is involved in up to 30% of patients with
PAD.2 Percutaneous transluminal angioplasty (PTA), with or without stent placement,
is the preferred treatment option in most of these patients. For a successful technical outcome, the use of iodinated contrast media and ionizing radiation is still necessary in most procedures to create 2-dimensional (2D) digital subtraction angiographies (DSAs) to visualize the location of the lesion and evaluate the severity of a stenosis.2
In recent years, the policy to reduce radiation exposure for patients and physicians, as well as the amount of nephrotoxic contrast, has been embraced globally.
During the preprocedural workup, contrast-enhanced magnetic resonance angiography (CE-MRA) or computed tomography (CT) angiography (CTA) are routinely used to image the aortic-femoral trajectory. The development of new image guidance tools in angiography suites allows for continuous fusion guidance of such preprocedural imaging during endovascular interventions. The technique of 3-dimensional (3D) image fusion relies on performing a rigid registration of preprocedural image data, such as CTA or CE-MRA, to a preprocedurally acquired cone-beam CT (CBCT) or 2 fluoroscopic orthogonal images. Registration takes approximately 5 to 10 minutes and is based on the fusion of bony landmarks and, in case of CTA, arterial wall calcifications. Image fusion significantly reduces the volume of iodinated contrast in endovascular aneurysm repair (EVAR) procedures.3 In addition, it may reduce the total amount of
ionizing radiation, fluoroscopy time, and procedure time, especially in more complex cases.3 This is particularly true for the juxtarenal aortic anatomy with relatively fixed
orifices of the target visceral arteries. However, the introduction of stiff guidewires and delivery systems during EVAR procedures will result in deformation of the iliac arteries4
and can disturb the accuracy of the rigidly fused images of these access arteries.5 In
our clinical experience, this is particularly the case in elongated iliac arterial anatomy. A few studies have described the feasibility of the 3D image fusion technique for peripheral artery interventions.6,7 These studies, however, did not investigate the
effect of the insertion of guidewires and catheters on the fusion accuracy during endovascular iliac artery interventions, which is the main subject of the current study. We conducted a systematic review of the available literature regarding the 3D image fusion technique in endovascular iliac artery interventions to evaluate the available clinical information on this subject.
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METHODS
Technical validation of 3D fusion technique
Periprocedural analysis
Technical validation of the 3D fusion technique was evaluated in common and/or external iliac artery lesions that were treated during elective percutaneous interventions (i.e., PTA or recanalization, with or without additional stenting) in the angiography suite. All procedures were performed in patients with disabling claudication that did not respond to a supervised exercise program. The local medical ethical committee (METC azM/UM) approved the study protocol, and all patients gave written informed consent before study inclusion.
Besides a clinical examination, measurement of ankle-brachial indices, and treadmill tests, all patients underwent a preprocedural peripheral artery CE-MRA (Intera 1.5T; Philips Healthcare, Best, The Netherlands). A standard T1-weighted fast field echo protocol was used with a field of view of 430 × 300 × 105 mm3 and an
acquired spatial resolution of 1.41 × 1.41 × 3.00 mm3. The reconstructed voxel size
was 1.22 × 1.22 × 3.00 mm3. The first step for fusion imaging was the segmentation
of the preprocedural CE-MRA. The Philips XperGuide software (Version R1.4.0.10030; Philips Healthcare) was used to manually remove all anatomical structures, apart from the aorta and iliac and femoral arteries. The resulting segmented 3D data set is visible during the intervention.
Before the start of the endovascular procedure, patients were placed supine on a vacuum mattress on the angiography table. When the vacuum was created, the mattress formed a mold around the patient. This minimized leg and pelvic movement during the intervention, thus limiting registration errors caused by movement artifacts. A noncontrast-enhanced CBCT of the pelvic area was created at the beginning of the procedure using the flat panel detector of the C-arm angiography system (Allura Xper FD20; Philips Healthcare). The 8-second CBCT was reconstructed to a 3D volume with a maximum spatial resolution of 0.65 × 0.65 × 0.65 mm3 and was automatically
transferred to the 3D XtraVision workstation (Philips Healthcare).
A technical physician performed the manual 3D-3D registration of the original preprocedural CE-MRA and CBCT. Bony landmarks, such as the vertebrae and femoral heads, were used for registration. In addition, calcified spiculae of the arterial walls, as visible on the CBCT, were registered to the vessel lumen, as visible on the CE-MRA (Figure 2.1). The image registration linked the CE-MRA to the 3D coordinate system of the C-arm. Therefore, the view angle of the segmented CE-MRA images followed rotations of the C-arm, table movements, and furthermore, adapted to magnification. The time to perform the registration was recorded. The endovascular procedure was performed
under fusion guidance, using additional contrast runs whenever deemed necessary. All patients underwent an initial DSA run to confirm the accuracy of the fusion images. The treating physician visually scored the fusion accuracy of the entire vasculature of the overlay with respect to the DSA directly after the first obtained DSA (Figure 2.2A-B). Fusion quality was categorized as accurate (<2 mm), mismatch (2–5 mm), or inaccurate (>5 mm). If needed, the fused images could be manually translated or reregistered from the current fusion images to achieve a more accurate overlay before the actual revascularization procedure started. The DSAs and fusion images were saved for postprocedural analysis. Before the end of the procedure, a completion DSA confirmed the procedural success, defined as a <30% residual stenosis over the treated iliac lesion. Contrast runs were performed with the 4F Cobra catheter (Radifocus Glidecath, Terumo Europe, Leuven, Belgium); interventions were performed over a 0.035-inch angled Glidewire (Terumo Europe).
Postprocedural analysis and statistics
The image attributes of the initial DSA run were transcribed to the Digital Imaging and Communications in Medicine (DICOM) header of the corresponding secondary captured fusion images. This did not alter the image data of the fusion images but enabled the analysis of the secondary captured fusion images with the Cardiovascular Angiography Analysis System (CAAS) workstation (Release 7.5; PIE Medical Imaging, Maastricht, The Netherlands). The fusion images and DSAs were both analyzed with the Quantitative Vessel Analysis (QVA) of the CAAS software. After image calibration was performed using the known catheter size, the arterial wall contour lines were semiautomatically drawn. The contour coordinates were exported, and 2D centerline reconstructions were performed using Matlab R2015b software (The Mathworks, Inc.,
Figure 2.1. Manually performed rigid registration between the CBCT (red) and the CE-MRA (blue) in the axial, coronal, and sagittal planes. Bony landmarks and calcified speculae of the arterial walls, visible on CBCT, were registered to the vessel lumen of the CE-MRA.
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Natick, MA, USA). To perform a fair analysis between the corresponding points at the DSA and fusion image, a cross-correlation method (Appendix I) was used to pair points along the reconstructed centerlines. To overcome the various vessel lengths of patients, vessel length was normalized to a distance between 0 and 1, with 0 being the aorta bifurcation and 1 being the common femoral artery bifurcation. The cranial-caudal, lateral-medial, and absolute displacement were derived from the distance between the centerlines of the DSA and the fusion image (Figure 2.3A-D).
Figure 2.2. Two examples of image fusion as seen during the first DSA run. Panel A shows a patient where the fusion accuracy was scored inaccurate. The overlay can then be manually translated to improve the fusion accuracy. Panel B shows an example of an accurate fusion.
Figure 2.3. Example of displacement calculation between (A) DSA and (B) CE-MRA. Quantitative Vessel Analysis (QVA) software was used to segment the vessel wall, and the luminal centerline was calculated. (C) The left iliac trajectory of the DSA and CE-MRA images were overlaid. (D) The displacement between corresponding points on the centerline was evaluated in the lateral-medial and cranial-caudal direction. The absolute displacement was also calculated, which is represented by the black line (black arrow).
To determine the possible influence of the diagnostic catheter on the vascular anatomy, the centerlines of the DSA and fusion image were translated and aligned at the aorta bifurcation. The fusion image centerline was then rotated to optimize the match with the DSA, and the displacement analysis was repeated. However, different from previous analysis, catheterized iliac trajectories were compared with the noncatheterized iliac trajectories, which served as a reference.
We also analyzed the learning curve for performing the registration by calculating the average absolute displacement for every performed procedure.
Statistical analysis
Normally distributed data are reported as the mean ± standard deviation, and non-normally distributed data are reported as median (range). Statistical significance was analyzed with the independent t-test or Mann-Whitney U-test for normally and non-normally distributed data, respectively. P values were considered significant when α < .05.
Systematic review
Literature search
The PubMed/MEDLINE, Embase, and the Cochrane Database of Controlled Trials databases were searched to identify clinical studies published in English between January 2010 till August 2017 on the use of 3D image fusion technique during endovascular iliac artery interventions. The Medical Subject Heading terms used were “software” OR “computer-assisted surgery” or “multimodal imaging” OR “cone-beam computed tomography” OR “interventional radiology” OR “fluoroscopy” OR “three-dimensional imaging” OR “angiography,” in combination with (AND) “overlay” OR “fusion” OR “roadmap.” The same search terms were used as keywords, and all combinations of these keywords were added to the search as free-text terms, limited to the title and abstract.
Inclusion/Exclusion Criteria
Two authors (SRG and SGHH) independently reviewed the title and abstract of each manuscript that was identified with the broad search. A strict inclusion criterion was used. Manuscripts were included only when the 3D image fusion technique (both 2D-3D or 2D-3D-2D-3D registration) was used for periprocedural guidance during endovascular interventions of iliac artery obstructions. The reference lists of the selected manuscripts were assessed for further relevant publications. The 2 reviewers compared the articles for eligibility, and full papers were retrieved if 1 or both of the reviewers considered the title and abstract eligible.
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Data Collection and Quality Assessment
The extracted data included the number of patients, 3D image fusion details, type of endovascular intervention, and study endpoints. The 12-item Methodological Index for Non-Randomized studies (MINORS) scoring system was used to assess the methodological quality of the studies.8 A maximum score of 24 could be achieved (0
= not reported, 1 = reported but inadequate, or 2 = reported and adequate), where a score of ≤14 is considered poor quality, 15 through 22 is moderate quality, and ≥23 is good quality. Two authors (SRG and SGHH) independently scored the included studies. The opinion of a third reviewer (JPPMdV) was sought in case of discrepancies.
RESULTS
Technical validation of the 3D fusion technique
We evaluated 11 patients (7 men [63.6%]; median age, 68 years [range, 53–88 years]) with a total of 15 common and/or external iliac artery occlusion (n = 5) and/or stenosis (n = 10). All suffered intermittent claudication that did not respond to a supervised exercise program. Of the 11 patients, 4 had 2 iliac artery lesions, and 3 of those 4 patients had bilateral lesions. At the time of the initial DSA run, 2 patients were catheterized on both sides. One patient did not undergo PTA because the stenotic lesion observed on the CE-MRA was non-significant on the initial DSA run. The procedures (1 DSA, 9 PTAs with additional stenting, and 5 recanalizations with additional stenting) were successful and uncomplicated. No complications occurred related to the use of the 3D image fusion technique.
The median time between the preprocedural CE-MRA and the PTA procedure was 32 days (range, 17–82 days). The median volume of administered iodinated contrast agent was 28 mL (range, 15–56 mL). The median radiation dose (dose area product) of the procedures was 54.1 Gycm2 (range, 18.0–159.0 Gycm2), and median fluoroscopy time (in minutes:seconds) was 06:03 (range, 01:29–23:36). The median total procedure time from femoral access to arterial closure was 49 minutes (range, 13–111 minutes).
Periprocedural analysis
Image fusion was feasible in all cases with a median time of 6 minutes (range, 2–10 minutes). The interventionalist visually scored the initial image fusion accuracy after acquiring the first DSA run. Fusion quality was judged accurate in 3 patients (27%), mismatch in 6 (55%), or inaccurate in 2 (18%). In case of a mismatch or inaccurate fusion quality, the fusion could be translated to a more accurate fusion quality before the intervention was continued.
In total, there were 22 iliac trajectories to analyze, of which 13 were iliac trajectories with catheter or guidewire, and 9 were iliac trajectories without. Two of the trajectories with catheter or guidewire were excluded from the analysis because of long occlusions present on the CE-MRA and DSA. The remaining 20 iliac trajectories (i.e., 9 without and 11 with a catheter or guidewire) were used to determine the accuracy of the registration, the influence of the catheter on the image vasculature, and the possible learning curve present when performing the registration of the CE-MRA to the CBCT.
Postprocedural analysis
The lateral-medial, cranial-caudal, and absolute displacements were determined by comparing the centerline of the fusion image with the initial DSA centerline (n = 20). The aortic bifurcation was visible on all DSA and fusion images. On average, the centerline of the fusion image was registered more medial and caudal compared with the DSA, –0.6 ± 3.7 mm and –0.2 ± 3.0 mm, respectively (Figure 2.4). The registration error between the DSA and the fusion image increased toward the distal end of the external iliac artery. The mean absolute registration error between the DSA and the fusion image from the aortic bifurcation to the femoral artery bifurcation was 4.0 ± 2.5 mm.
Influence of inserting a catheter or guidewire in the iliac arteries
Catheterized and noncatheterized trajectories were compared to determine the influence of the endovascular equipment on fusion accuracy. The registration errors at the noncatheterized sites were equal to the errors of the catheterized sites (Figure 2.5, A vs D, B vs E, and C vs F). The average displacement errors between the iliac vessel trajectories without (n = 9) and with (n = 11) a catheter were (1) lateromedial, 0.0 ± 0.8 mm versus 0.1 ± 0.9 mm (P = .447), (2) craniocaudal, 0.2 ± 0.6 mm versus 0.4 ± 0.7 mm, (P = .255), and (3) Absolute, 0.9 ± 0.6 mm versus 1.0 ± 0.6 mm (P = .447). Of note, the displacement in the aortic bifurcation (distance 0) is perfect because this point was used to match the DSA and fusion image.
Learning curve
The average displacement error decreased with increasing number of registrations performed by the technical physician, as seen in Figure 2.6. The trend line shows the average displacement error was reduced from 5.6 mm to 2.5 mm after 11 procedures were performed.
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Figure 2.4. Displacement of the fusion image relative to DSA for all 20 iliac trajectories that could be analyzed. Displacement is shown in the (A) lateral-medial and (B) cranial-caudal direction. (C) The absolute displacement error increases towards the common femoral artery. Lengths of all 20 iliac trajectories were normalized from 0 to 1, with 0 being the location of the aorta bifurcation and 1 the common femoral artery bifurcation. The blue line represents the mean ± standard deviation of all displacement lines. Notably, some of the displacement lines were interrupted owing to an occluded segment for which no displacement could be determined.
Systematic review
Included studies
The literature search yielded 8441 articles, of which 8437 were excluded because there was (1) no intraoperative use of the 3D image fusion technique and/or (2) no iliac artery intervention was performed (Figure 2.7). The crosscheck of references of the eligible articles did not identify additional manuscripts. The full-text of 4 manuscripts was evaluated, after which 2 articles were excluded. The first was excluded because the report was an EVAR procedure with an iliac side-branch device9 and the second
because of the treatment of an internal iliac artery aneurysm.10 Two manuscripts
met the inclusion criteria.6,7 The study characteristics are reported in Table 2.1. The
methodological quality of both articles was poor, mainly because of a lack of a control group. The studies used both CTA and CE-MRA for the 3D image fusion technique. Both studies used the Allura XtraVision 8.3 workstation (Philips Healthcare).
Figure 2.5. (A) The lateral-medial, (B) cranial-caudal, and (C) absolute displacement of the fusion image relative to DSA for iliac trajectories without a catheter (n = 9) are shown; (D-F) similar displacements are shown for the catheterized (n = 11) iliac trajectories. Lengths of all iliac trajectories were normalized from 0 to 1, with 0 being the location of the aorta bifurcation and 1 the common femoral artery. The blue lines represent the mean ± standard deviation of the displacement lines.
Figure 2.6. The average displacement error between the DSA and fusion image for all 11 performed procedures. The registration of the images became more accurate with increased experience of the technical physician.
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Figure 2.7. Flowchart of the literature search.
Description of studies
Ierardi et al.7 evaluated 5 patients with aorto-iliac steno-occlusive disease, of which 4
patients underwent preprocedural CTA and 1 patient underwent CE-MRA. Registration was based on arterial wall calcifications and bony landmarks. The registration process took approximately 3 to 4 minutes and was performed by a skilled interventional radiologist. The operator judged the overlay accuracy and decided whether the fusion was acceptable or not. All fusion images were sufficient, meaning no CBCT scans had to be repeated.
To evaluate the feasibility, precision, and added value of image fusion guidance in peripheral artery interventions, 17 patients were treated under fusion guidance for 14 common and/or external iliac artery and 6 superficial femoral artery and/or popliteal artery interventions in the study by Sailer et al.6 All interventions were performed under
local anesthesia in the angiography suite. Registration was performed based on vessel wall calcifications, bony and organ landmarks, and took the interventional radiologists an average of 5 ± 2 minutes. The average maximum difference between the position of the vasculature on angiography and CE-MRA/CTA fusion roadmap was 1.86 ± 0.95 mm after the exclusion of 3 patients with substantial leg and pelvis movement. The fusion roadmap had an added value in 75% of the procedures, and pretreatment angiography series could be omitted in 47% of the patients when evaluated by the executing interventional radiologist. Completion angiograms were performed in all patients to confirm treatment success and to detect possible complications.
2
Search results (n = 8441) 4000 Pubmed/Medline 4378 Embase
63 Cochrane database of controlled trials
Full-text study excluded (n = 2) Reason:
- Endovascular aortic repair procedure with the
addition of an iliac side branch device
- Coil embolization and stent placement of a left
internal iliac artery aneurysm Full-text assessed for eligibility (n = 4)
Duplicate publications and irrelevant articles (title/abstract) excluded (n = 8437)
Table 2.1. Included studies of the systematic review. Study N Study Type Pre-operative Imaging Fusion with
Intervention Endpointsa MINORS
Ierardi
2015 7
5 Feasibility
study
CTA/MRA CBCT Angioplasty and
stent placement in aorto-iliac steno-occlusive disease IC: 20 (20-40) DAP: 60.05 (55.02-63.75) PT: 33 (27-38) FT: 12.42 (10.17-14.25) RT: 3-4 11 Sailer 2014 6 17 Feasibility study CTA/MRA CBCT Recanalization and/or stenting and/or PTA in CIA/ EIA/SFA/popliteal artery/tibiofibular trunk IC: 58 (30-125) PT: 102 (45-260) RT: 5±2 RE: 1.86 (95% CI 0-3.72) 10
Abbreviations: CBCT, cone-beam computed tomography; CI, confidence interval; CIA, common iliac artery; CTA, computed tomography angiography; DAP, dose area product (Gycm2); EIA, external iliac artery; FT, fluoroscopy time (min); IC, iodinated contrast (mL); IIA, internal iliac artery; MRA, magnetic resonance angiography; PT, procedure time (min); PTA, percutaneous transluminal angioplasty; RE, registration error (mm); RT, registration time (min); SFA, superficial femoral artery;
aVariables are given as mean (range) or 95% confidence interval (CI).
DISCUSSION
Our study is the first study to validate the reliability of 3D image fusion technology for interventions of iliac artery obstructions. The visual errors between the fusion images and DSAs were scored <5 mm in 9 of 11 patients. The mean absolute registration error for all iliac trajectories was small (4.0 ± 2.5 mm). On average, the fusion image was registered slightly more medial (–0.6 ± 3.7 mm) and caudal (–0.2 ± 3.0 mm) with respect to the DSA run. The average displacement decreased to 2.5 mm with increasing experience with the technique. The absolute registration error after post-procedural translation and rotation between iliac trajectories without and with catheters was small (0.9 ± 0.6 mm vs. 1.0 ± 0.6 mm), and the difference was not significant (P = .447). Hence, there was no significant influence of the catheters or guidewires on the accuracy of the image fusion technique.
Image fusion accuracy can be influenced by the image quality of the preoperative CTA or CE-MRA. In the current study, a regular preprocedural CE-MRA was used for the image fusion technique, which was of sufficient quality to perform the interventions under fusion guidance. However, fusion imaging has some limitations, such as stent artifacts at the location of the lesion and the occurrence of long-segment occlusions,
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