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Chapter 35
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Surveillance After Elective EVAR
Blanca Călinescu
1
Army’s Clinical Emergency Center for Cardiovascular Diseases, Bucharest, Romania; 2“Vasile Goldiş” Western University of Arad, Arad, Romania;
3
“Iuliu Haţieganu” University of Medicine and Pharmacy Cluj-Napoca, Cluj-Napoca, Romania; 4Praxis für Gefäß- und Thoraxschirurgie Rolf
Dammrau, Düren, Germany; 5Düren County Hospital, Düren, Germany
1,2
, Ionel Droc1, Aurel Mironiuc3, Rolf Dammrau4, Horst Kinkel
5
Chapter Outline
Introduction 403
Postoperative Surveillance 403
Contrast-Enhanced Computed Tomography 404
Magnetic Resonance Imaging 405
Plain Abdominal Radiography 405
Duplex Ultrasound/Contrast-Enhanced Ultrasound 405
EVAR Surveillance Protocol 406
References 408
INTRODUCTION
With the introduction into clinical practice and increasingly frequent application of endovascular repair of abdominal aortic
aneurysms (EVAR), along with the well-known benefits of minimally invasive interventions, controversies arise associated to new treatment methods. These controversies include the medium- and long-term results of EVAR influenced by the
potential occurrence of procedure-specific complications (Fig. 35.1).
Results of several randomized controlled trials show a significant postprocedural complication rate up to 8–9 years
[1,2]. Complications arising from endovascular abdominal aortic aneurysm repair occur in 40% of patients in the first
4 years post-EVAR, resulting in a nonneglectable reintervention rate of 20% [3]. A recent study deemed lifelong surveillance necessary to identify long-term complications and plan a possible reintervention [4].
Since the reported results of EVAR Trial 1 completed in 2004, the most recent technological advancements
as well as increase of operator experience significantly reduced the incidence of postinterventional peripheral
embolization, aneurysm rupture, or stent-graft migration. Continuous challenge of anatomical boundaries and extension of EVAR indication, however, maintain the risk of endoleak development, which is the main reason for pursuing
lifelong patient follow-up.
POSTOPERATIVE SURVEILLANCE
To maintain the long-term success of EVAR, namely to eliminate the risk of aneurysm rupture, lifelong, regular imaging
surveillance must redocument and reassure the exclusion of the aneurysm sac from the systemic circulation.
It is critical for the basic imaging method to accurately
l detect and characterize endoleaks;
l assess morphological changes of the residual sac through measurement of aneurysm size and if possible volume
calculation;
l detect mechanical changes in the stent graft, such as migration, kinking, or structural failure
In addition to diagnostic accuracy requirements, the basic imaging method should meet other criteria as well: be cheap,
repeatable, noninvasive, widely available, and safe.
In practice, there are several imaging methods included in the follow-up protocol of patients with abdominal aortic
aneurysms (AAA) treated by EVAR: contrast-enhanced computed tomography (CTA), magnetic resonance imaging (MRI),
New Approaches to Aortic Diseases from Valve to Abdominal Bifurcation. http://dx.doi.org/10.1016/B978-0-12-809979-7.00035-3
Copyright © 2018 Elsevier Inc. All rights reserved.
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FIGURE 35.1 Modes of endovascular repair of abdominal aortic aneurysms (EVAR) failure.
duplex ultrasonography (DUS), contrast-enhanced ultrasonography (CEUS), plain abdominal radiography (Rx), and digital
subtraction angiography (DSA), each of them having their own advantages and drawbacks.
Surveillance protocols for EVAR that are the current standard of care were derived from early trials not having the
long-term data available that we have today, confiding mainly in the instructions for use for the devices. These protocols
include serial CTA and plain abdominal radiographs at 1, 6, 12 months post-EVAR and yearly thereafter. Major concerns
with this protocol are the potential carcinogenic effects of the cumulative radiation dose and nephrotoxicity of the contrast
medium. In addition, there are cost-associated issues, CTA follow-up costs representing a third of the total costs of EVAR
[5]. In recent years, several studies have focused on establishing a safe, effective, cost-efficient EVAR follow-up protocol,
but without reaching a consensus [6,7]. The most reliable alternative imaging method for CTA is still a highly debated issue.
Contrast-Enhanced Computed Tomography
In current clinical practice, CTA is considered the “gold standard” imaging method for EVAR surveillance. The highresolution images and volumetric data sets obtained allow accurate aneurysm morphology assessment as well as detection
of postprocedural complications.
Long-term application, for more than 20 years, of CTA-based protocols consisting of CTA examination at 30 days,
6 months, 12 months, and then yearly after EVAR proved effective but raised several concerns.
Given that in the case of endoleaks intrasac flow characteristics differ, these can be depicted at various time intervals
after contrast-medium administration. From this consideration a multiphasic CT angiography was proposed including precontrast as well as early and delayed postcontrast acquisitions. Concerns regarding this protocol refer to the high radiation
dose, contrast-medium nephrotoxicity [8], and high cost involved.
The average radiation dose calculated for an examination is 15 mSv, although this value may differ depending on
the device used. Patients included in the CTA-based follow-up protocol accumulate an average radiation dose of about
50–100 mSv, at which a high cancer risk was identified [9,10].
Box 35.1 shows the estimated dosage of ionizing radiation a patient receives per examination. It is noteworthy that a
single abdominal CT scan without contrast is equivalent to 100 chest X-rays.
The stochastic risk of fatal, radiation-induced tumor is estimated to be 5%/Sv radiation; therefore, the risk of cancer
induction by a single CTA examination is around 1–1500 (International Commission on Radiological Protection, 2007).
These numbers support the need for alternative EVAR follow-up imaging, particularly in younger patients.
Another disadvantage is that CTA requires administration of iodinated contrast agents, which are associated with nephrotoxic effects. Renal insufficiency is a comorbidity encountered in 80% of patients with AAAs, being the leading risk
factor for contrast-induced nephrotoxicity [8]. A study that evaluated the risk of developing contrast-induced nephropathy
showed 11% incidence of renal impairment with 0.6% mortality rate after repeated CTA examinations [11].
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Box 35.1 Estimated Dosage of Ionizing Radiation
l
Chest X-ray
l
Head CT
l
Abdomen-pelvis native
l
Abdomen-pelvis with contrast
l
Triphasic post-EVAR follow-up
l
Hiroshima A bomb (mean)
*Doses shown in mSv (milisieverts). Numbers in parentheses show the relative ratio compared to chest
X-ray. CT, computed tomography; EVAR, endovascular repair of abdominal aortic aneurysm.
0.05 (1×)*
2 (40×)
10 (200×)
15 (300×)
25 (500×)
20 (400×)
It is also proven that although CTA accurately diagnoses endoleaks, in certain cases, CTA fails to specify the type and
characteristics of the periprosthetic blood flow, especially in low flow type 2 endoleaks. A study published by Stravropoulos
et al. evaluating the diagnostic accuracy of CTA resulted in a specificity (Sp) of 60% and sensibility (Se) of 81% in endoleak
classification and characterization [12].
Magnetic Resonance Imaging
MRI is a noninvasive examination method based on the intravenous injection of gadolinium chelates (0.1 mmol/L). The
imaging performance of this method depends largely on the metal composition of the stent graft. Nitinol-based stents are
in general suitable for MRI, but elgiloy stents, as well as stainless steel stents, usually cause artifacts that render the study
nondiagnostic [13].
MRI offers an advantage over CTA as it is free from radiation and does not require the administration of iodinated
contrast medium.
As disadvantages, in addition to the limitations given by the metal composition of the stent graft, the method has limited
use in patients with metallic implants such as pacemaker, defibrillator, neurostimulator, mechanical heart valve, or ferromagnetic intraocular devices.
Several studies involving patients with nitinol stent-grafts resulted in a specificity and sensitivity of MRI examination
at least equal to that of CTA examination [14–16]. According to a study conducted by Ayuso et al. MRI has a Se of 100%
and a Sp of 82% in identifying type II endoleaks [17]. In another study including thoracic aortic endografts, MRI and CTA
were found to be equally accurate in the assessment of the aneurysm morphology (measurement and stent-graft position),
but MRI proved less accurate than CTA in the detection of all type endoleaks [18]. New blood-pool MR contrast agents may
improve the detection of low-flow endoleaks [19].
Although the overall results are encouraging MRI cannot be considered as replacement for CTA in the follow-up exami-
nation of EVAR not only considering its limitations, but also considering the lack of availability and high costs.
Plain Abdominal Radiography
Radiography continues to be used in basic post-EVAR surveillance despite the availability of advanced imaging modalities. It is applied as an adjunct investigation method for the detection of structural changes of the stent-graft that might
be missed on CTA. Radiography is considered by some authors to be superior to CTA in this regard [20]. Any protocol
should include antero-posterior and lateral acquisitions for depiction of stent-graft migration and component separation as well as oblique acquisition able to detect wire fractures, although the clinical importance of the later is not fully
elucidated.
It is preferable to perform radiography prior to same-day CT examination so that excreted contrast material in the collecting system does not obscure the stent-graft [21].
Duplex Ultrasound/Contrast-Enhanced Ultrasound
Color duplex ultrasound has been proposed as an alternative EVAR surveillance imaging method for CTA. Ultrasound
offers several advantages compared to CTA, including lower cost, absence of radiation exposure and nephrotoxicity, ensuring excellent patient safety and compliance. However, it is largely operator dependent and the quality of images can be
adversely affected by the patient’s habitus and excess bowel gas, this being the probable reason for the poor performance
of DUS in endoleak detection.
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FIGURE 35.2 (A) Contrast-enhanced ultrasound (CEUS) aspect of a type III endoleak misdiagnosed by computed tomography (CT) as type II endoleak
originated from the inferior mesenteric artery that prompted reintervention. (B) CEUS aspect of a type II endoleak originating from an accessory renal
artery erroneously diagnosed by CT as type I endoleak originating from the proximal attachment site of the endoprosthesis.
A critical component of aneurysm imaging and subsequent endoleak management is determination of the aneurysm
size. Aneurysm enlargement may prompt intervention, whereas aneurysm shrinkage is reassuring.
To consider DUS as an alternative to CTA in EVAR surveillance and to introduce a new protocol based on ultrasonographic examinations it was necessary for DUS to prove a good correlation with measurements performed with CTA.
Several studies found that aneurysm size measurements obtained with DUS correlate well with those obtained with
CT [22,23]. Our group recently performed a prospective, multicenter study [24] to determine the diagnostic accuracy of
DUS and CEUS compared to the reference standard, CTA, in the diagnosis of postoperative complications as well as in
the detection of morphological changes of the residual aneurysm sac (diameter measurement). The Pearson coefficient
correlation was found to be 0.91 indicating a large degree of correlation between DUS and CT when measuring aneurysm
size following EVAR.
There have been also disagreements in the size measurements, ultrasound aneurysm measurements found to be typically
smaller than those taken with CT [13]. Other investigators have shown that changes in AAA measurement may be misrepresented on DUS [25]. To reduce the variability there is an urgent need for standardization of DUS scanning techniques given
that in current clinical practice protocols vary significantly from one institution to another [26–28].
Although aneurysm enlargement establishes that the indication for intervention is the accurate diagnosis and character-
ization of endoleaks that guide it.
The reported sensitivities of DUS compared with CT vary considerably, ranging from 25% to 100% [22–24,29–31]. A
recent bivariate metaanalysis of 21 published studies comparing CTA with color duplex ultrasound and CEUS showed that
the sensitivity and specificity of DUS for endoleak detection were 77% and 94%, respectively. In comparison, the sensitivity and specificity of CEUS for endoleak detection were 98% and 88%, respectively [7].
It is unanimously accepted that CEUS improves the diagnostic accuracy of DUS in endoleak detection and characterization. Several studies found it even to be superior to CTA or MRI in this regard [6,7,22–24,29,32]. The additional temporal
information provided by CEUS is crucial in the diagnosis and characterization of low-flow endoleaks. We found CEUS to
have an advantage over CT in the follow-up of type II endoleaks (Fig. 35.2A and B) as well as in the follow-up of complex
aneurysms treated with fenestrated or branched endografts allowing the assessment of flow characteristics in the branches
and stented fenestrations as well as the renal perfusion (Fig. 35.3A and B) [24].
Furthermore, the ultrasonic microbubble contrast agent employed is safe with no known nephrotoxicity [33].
EVAR SURVEILLANCE PROTOCOL
In the absence of randomized trials to evaluate novel surveillance protocols, a few recommendations can be made based on
available evidence. Clearly, routine CTA is unnecessary.
It is also clear that none of the mentioned imaging methods can be used as a stand-alone imaging method and that an
effective EVAR surveillance protocol should include several modalities, each with specific indications, reducing radiation
exposure, nephrotoxicity, and costs as much as possible.
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FIGURE 35.3 (A) Renal perfusion assessed by duplex ultrasonography; (B) Renal perfusion assessed by contrast-enhanced ultrasound.
FIGURE 35.4 Endovascular repair of abdominal aortic aneurysms (EVAR) surveillance protocol. AAA, abdominal aortic aneurysm; CEUS, contrast-
enhanced ultrasonography; CTA, contrast-enhanced computed tomography; DUS, duplex ultrasonography.
A new effective and safe DUS/CEUS-based surveillance regimen can be proposed based on the results of aforemen-
tioned studies (Fig. 35.4).
One limitation of DUS/CEUS, however, is in the detection of structural abnormalities within the endograft. The
replacement of CT with DUS/CEUS as a surveillance tool would remove the capability of structural imaging of the
endograft and thus mandate the inclusion of an abdominal X-ray as part of any new protocol. A recent study performed by G.J. Harrison et al. concluded that follow-up after EVAR primarily based on DUS and Rx is feasible and
safe [31].
At 30 days, post-EVAR is recommended to perform triphasic CTA together with DUS/CEUS and plain abdominal
radiography to outline morphologic changes after the procedure, to detect endoleaks, migration, or structural problems.
The results of these investigations should be recorded for comparative purposes. One group reported that precontrast
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acquisitions may only be necessary in the first post-EVAR examination, with all subsequent examinations acquiring only
postcontrast images, using the initial native scan for comparison [34].
A normal 30-day CTA was correlated with a 92.9% chance of complication-free EVAR at a mean of 3.4 years and a
97.1% chance of freedom from undergoing a secondary intervention [35].
At 6 and 12 months post-EVAR, DUS/CEUS + abdominal radiography can be performed. If there is a continued lack of
endoleak and the aneurysm sac is stable or has shrunk, then further follow-up is performed with yearly DUS/CEUS + Rx.
Increase in sac size, detection of high velocity flow within the aneurysm sac suggestive of an endoleak, structural abnormalities
in the graft, or inability to obtain adequate pictures of the graft with DUS/CEUS would require further evaluation with CTA.
Adoption of this protocol would lead to a significant reduction in the number of CT scans required as part of the postoperative surveillance with a resultant reduction in exposure to both ionizing radiation and intravenous contrast and a
significant cost saving.
Follow-up of patients after EVAR should also include ankle-brachial pressure index measurement on a regular basis.
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[2] De Bruin JL, Baas AF, Buth J, Prinssen M, Verhoeven EL, Cuypers PW, et al. Long term outcome of open or endovascular repair of abdominal aortic
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[5] Sternbergh WC, Greenberg RK, Chuter TA, Tonnessen BH. Redefining postoperative surveillance after endovascular aneurysm repair: recommen-
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[6] Dill-Macky M, Wilson R, Sternbach Y, Kachura J, Lindsay T. Detecting endoleaks in aortic endografts using contrast-enhanced sonography. Am J
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[7] Mirza TA, Karthikesalingam A, Jackson D, Walsh SR, Holt PJ, Hayes PD, Boyle JR. Duplex ultrasound and contrast-enhanced ultrasound versus com-
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[8] Walsh SR, Tang TY, Boyle JR. Renal consequences of endovascular abdominal aortic aneurysm repair. J Endovasc Ther 2008;15:73–82.
[9] Brenner DJ, Doll R, Goodhead DT, Hall EJ, Land CE, Little JB, et al. Cancer risks attributable to low doses of ionizing radiation: assessing what we
really know. Proc Natl Acad Sci USA 2003;100(24):13761–6.
[10] Ohki T. Long-term AAA sac pressure monitoring. Endovascular Today November 2006:55–63.
[11] Tepel M, Aspelin P, Lameire N. Contrast-induced nephropathy. A clinical and evidence-based approach. Circulation 2006;113:1799–806.
[12] Stavropoulos SW, Clark TW, Carpenter JP, Fairman RM, Litt H, Velazquez OC, Insko E, Farner M, Baum RA. Use of CT angiography to classify
endoleaks after endovascular repair of abdominal aortic aneurysms. J Vasc Interv Radiol 2005;16:663–7.
[13] Walker TG, Kalva SP, Yeddula K, et al. Clinical practice guidelines for endovascular aneurysm repair: written by the standards of Practice Committee
for the Society of Interventional Radiology and endorsed by the Cardiovascular and Interventional Radiological Society of Europe and the Canadian
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[14] Cejna M, Loewe C, Schoder M, et al. MR angiography vs CT angiography in the follow-up of nitinol stent grafts in endoluminally treated aortic
aneurysms. Eur Radiol 2002;12:2443–50.
[15] Insko EK, Kulzer LM, Fairman RM, Carpenter JP, Stavropoulos SW. MR imaging for the detection of endoleaks in recipients of abdominal aortic
stent-grafts with low magnetic susceptibility. Acad Radiol 2003;10:509–13.
[16] van der Laan MJ, Bartels LW, Viergever MA, Blankensteijn JD. Computed tomography versus magnetic resonance imaging of endoleaks after
EVAR. Eur J Vasc Endovasc Surg 2006;32:361–5.
[17] Ayuso JR, de Caralt TM, Pages M, Riambau V, Ayuso C, Sanchez M, et al. MRA is useful as a follow-up technique after endovascular repair of aortic
aneurysm with nitinol endoprostheses. J Magn Reson Imaging 2004;20:803–10.
[18] Weigel S, Tombach B, Maintz D, et al. Thoracic aortic stent graft: comparison of contrast-enhanced MR angiography and CT angiography in the
follow-up. Initial results. Eur Radiol 2003;13:1628–34.
[19] Ersoy H, Jacobs P, Kent CK, Prince MR. Blood pool MR angiography of aortic stent-graft endoleak. Am J Roentgenol 2004;182:1181–6.
[20] Fearn S, Lawrence-Brown MM, Semmens JB, Hartley D. Followup after endovascular aortic aneurysm repair: the plain radiograph has an essential
role in surveillance. J Endovasc Ther 2003;10:894–901.
[21] William Stavropoulos S, Charagundla SR. Imaging techniques of detection and management of endoleaks after endovascular aortic aneurysm repair.
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[22] Raman KG, Missig Carroll N, Richardson T, Muluk SC, Makaroun MS. Color-flow duplex ultrasound scan versus computed tomographic scan in
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[23] Gray C, Goodman P, Herron CC, Lawler LP, O’Malley MK, O’Donohoe MK, McDonell CO. Use of colour duplex ultrasound as a first line surveil-
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[24] Droc I, Călinescu FB, Droc G, Blaj C, Dammrau R. Aortic stenting. Min Invas Ther Allied Technol 2015;24(5):296–304.
[25] d’Audiffret A, Desgranges P, Kobeiter DH, Becquemin JP. Follow-up evaluation of endoluminally treated abdominal aortic aneurysms with duplex
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[26] Sato DT, Goff CD, Gregory RT, et al. Endoleak after aortic stent graft repair: diagnosis by color duplex ultrasound scan versus computed tomogra-
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[27] Abada HT, Sapoval MR, Paul JF, de Maertelaer V, Mousseaux E, Gaux JC. Aneurysmal sizing after endovascular repair in patients with abdominal
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[28] Sprouse LR, Meier III GH, Lesar CJ, Demasi RJ, Sood J, Parent FN, et al. Comparison of abdominal aortic aneurysm diameter measurements
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[29] Cantisiani V, Ricci P, Grazhdani H, Napoli A, Fanelli F, Catalano C, Galati G, D’Andrea V, Biancari F, Passariello R. Prospective comparative
analysis of colour-doppler ultrasound, contrast-enhanced ultrasound, computed tomography and magnetic resonance in detecting endoleak after
endovascular abdominal aneurysm repair. Eur J Endovasc Surg 2011;41:186–92.
[30] Wolf YG, Johnson BL, Hill BB, et al. Duplex ultrasound scanning versus computed tomographic angiography for postoperative evaluation of endo-
vascular abdominal aortic aneurysm repair. J Vasc Surg 2000;32:1142–8.
[31] Harrison GJ, Oshin OA, Vallabhaneni SR, Brennan JA, Fisher RK, McWilliams RG. Surveillance after EVAR based on duplex ultrasound and
abdominal radiography. Eur J Vasc Endovasc Surg 2011;42:187–92.
[32] Giannoni MF, Fanelli F, Citone M, Cristina Acconcia M, Speziale F, Gossetti B. Contrast ultrasound imaging: the best method to detect type II
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[33] Cosgrove DO, Kiely P, Williamson R, Blomley MJ, Eckersley RJ. Ultrasonographic contrast media in the urinary tract. BJU Int 2000;86(Suppl.
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[34] Lezzi R, Cotroneo AR, Filippone A, et al. Multidetector CT in abdominal aortic aneurysm treated with endovascular repair: are unenhanced and
delayed phase enhanced images effective for endoleak detection? Radiology 2006;241:915–21.
[35] Johnstone JK, Oderich GS. Mechanisms of EVAR failure and new surveillance strategies. Endovascular Today February 2014:64–7.
Chapter 36
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Dissection of the Abdominal Aorta
Lucian Florin Dorobantu
Monza Hospital, Bucharest, Romania
Chapter Outline
Introduction 411
Symptoms and Signs 411
Diagnosis 412
INTRODUCTION
Aortic dissection was first recognized in 1760 by the doctor of George II who died from a transverse fissure on the inner
side of the ascending aorta through which blood passed in its external coat to form an ecchymosis and caused a cardiac
tamponade.
Laennec introduced the term of dissecting aneurysm in 1826 [1]. The first author who described the difference in prognosis between dissections that have origin in the descending aorta compared with those in the ascending aorta was Thomas
Peacock in 1843 [2]. He described later, in 1863, three cases of abdominal dissection [3].
Aortic dissection is rarely limited to the abdominal aorta. Usually, it involves the thoracic aorta and may extend in an
antegrade fashion into the abdominal aorta. Isolated and spontaneous dissection of the abdominal aorta (not associated
with blunt trauma or with descending thoracic aortic dissection) represents less than 2% of all aortic dissections [4]. There
are not large series of isolated acute aortic abdominal dissection (IAAAD) reported in the literature, this situation being
considered exceptional.
The largest number of patients was reported by Trimarchi et al. [5] who evaluated 1417 patients of International Registry
of Acute Aortic Dissection (IRAD) and found IAAAD in only 1.3%, 18 patients.
Because its incidence is extremely low, the natural history is unknown.
IAAAD is omitted from all standard and well-known classification of aortic dissection, Stanford and DeBakey. Only in
types I and III of DeBakey classification, this entity is included as a progression of the dissected thoracoabdominal aorta. It
is also included in the type A and B dissections according to Stanford classification, but only like an antegrade abdominal
extension of this type of dissection.
Management Strategies 412
References 414
SYMPTOMS AND SIGNS
There are no typical symptoms and signs for IAAAD. Abdominal pain is the most frequent symptom, although dissection
may be painless. If the abdominal dissection is a proximal extension of a type A or B dissection, the symptoms can be
those of the original point of the dissection (interscapular pain, etc.). Nevertheless, the abdominal pain is the most common
symptom in patients reported in the literature [5–7].
Hypertension is usually present in majority of patients with AAD, and the IAAAD makes no exception. Other predisposing factors of IAAAD seem to be similar to those of thoracic dissection, as atherosclerosis or pretexting abdominal
aneurysm [5,8].
Other signs and symptoms can be produced by occlusion of a major vessel once the IAAAD occurs. One leg or both
can become pale and pulseless and limb ischemia appears if dissection occludes the iliac artery or the aortic bifurcation.
Oliguria or anuria may appear with occlusion of the origin of the renal artery. Signs of mesenteric ischemia or infarction
may also be present.
New Approaches to Aortic Diseases from Valve to Abdominal Bifurcation. http://dx.doi.org/10.1016/B978-0-12-809979-7.00036-5
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Nonpenetrating injuries of the abdominal aorta are a rare cause of IAAAD due to the fact that the aorta is protected by
the posterior location [9]; if this lesion appears, it is usually associated with other major damages of the abdominal organs.
This problem is often fatal and the symptoms are related with the coexisting lesions or by the complications of the IAAAD.
There is no correlation observed between known syndromes such as Marfan and Ehler Danlos that are more likely connected with the aortic wall disorders and type A dissections and the IAAAD.
DIAGNOSIS
Usually the dissection of the abdominal aorta is diagnosed spontaneously in asymptomatic patients during computed
tomography (CT) examination for other reasons.
In patients with spontaneous IAAAD, Graham et al. [10] found that abdominal echocardiography and Doppler studies
were effective tools to demonstrate the false lumen and to evaluate the flow.
In symptomatic patients in which the IAAAD is suspected, the diagnosis is confirmed by a CT or magnetic resonance
imaging (MRI) investigation.
Contrast-enhanced CT shows direct or indirect signs of the dissection but may also disclose complications or provide
complementary data as precise vessels diameter and associated lesions that guide surgical treatment (Fig. 36.1).
Peterson et al. [11] are one of the few partisans of angiography in most acute posttraumatic dissection. Most of the
authors are suggesting that there is no need for aortography (Fig. 36.2) unless the MRI/CT is not rapidly available or if the
occlusion of a major branch of aorta is suspected.
In the IRAD study, the spiral CT was the most common examination in 83.3% of patients, being also used as the first
diagnostic exam in 72.2% of patients; MRI was used only in 4 of the18 patients, whereas the visceral or renal arteries
involvement was evidenced by CT and MRI. No aortography was used in this study [5].
MANAGEMENT STRATEGIES
There are few data regarding the strategies of management of the IAAAD. Because of the small number of patients, there
are no guidelines of definitive treatment [12].
Clinical examination and the presence of the complications at the time is crucial in the decision-making process.
In our opinion, asymptomatic patients with a normal aorta as well as the patients in whom the initial pain resolves and
with no other complication should be treated medically, with antihypertensive medication and beta blockers. There is poor
evidence that the aortic rupture may appear in the IAAAD evolution. Jonker et al. [13], in one of the largest series of these
patients, estimated this risk at about 10%.
The presence of complications, such as unrelenting pain despite the blood pressure control, pulse deficits, limb ischemia, mesenteric ischemia or infraction, acute renal failure, must be treated surgically. In our opinion, the surgical treatment
of the aortic dissection itself must preclude the treatment of its complications.
FIGURE 36.1 Contrast enhanced computed tomography exam—abdominal aortic dissection involving the left renal artery.
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The same surgical strategy should be considered in the situation in which the IAAAD coexists with abdominal aorta
dilatation [12]; the probability of aortic rupture is higher in this situation due to the fact that the dissection process affects
the already abnormal vascular wall in a negative manner.
In the particular case of traumatic abdominal dissection, the general opinion, based on short series of patients published
so far, is that the surgical treatment is indicated [14].
The goal of the surgical treatment of the aortic dissection is to close the entry site and decompress the false lumen. In the
false lumen, usually thrombosis occurs, but if this does not, the situation remains stable because the remaining flow cannot
cause further extension of the dissection.
The standard procedure is the open surgery. It consists of replacing the affected segment of the aorta with a Dacron
graft. If the affected segment (entry point) is suprarenal, the surgeon must implant or bypass the visceral branches into the
Dacron graft (Fig. 36.3).
Open repair of the IAAAD has been considered for years the gold standard of treatment with good results [13,15]. The
endovascular approach is the modern alternative to the standard procedure.
In IRAAD study, the majority of patients had a medical management (66%); the remaining six patients benefit from
open surgery, only one patient had an endovascular management [5].
FIGURE 36.2 Aortography—abdominal aortic dissection.
FIGURE 36.3 Dacron graft on the abdominal aorta with visceral artery implantation and left renal artery bypass.
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