|Year : 2020 | Volume
| Issue : 3 | Page : 237-240
Contrast-Enhanced ultrasound in endovascular aneurysm repair follow-up: Our experience
Cristina Busoni, Dalmazio Frigerio
ASST Vimercate, Via Santi Cosma e Damiano 10, 20871 Vimercate (MB), Italy
|Date of Submission||29-Oct-2019|
|Date of Decision||07-Nov-2019|
|Date of Acceptance||06-Dec-2019|
|Date of Web Publication||12-Sep-2020|
ASST Vimercate, Via Santi Cosma e Damiano 10, 20871 Vimercate (MB)
Source of Support: None, Conflict of Interest: None
Background: Endovascular aneurysm repair (EVAR) is actually the most common surgical technique used in the treatment of abdominal aortic aneurysm (AAA), worldwide. In EVAR, as we know, the most common complication is endoleak (EL), which is the most common cause of failure in the endovascular treatment of AAA. We can deduce that the surveillance and mid-term/long-term follow-up is mandatory and very important to detect EL. Contrast-enhanced ultrasound (CEUS) has been proposed as the gold standard in EVAR follow-up because its ability to detect EL (especially if they are at low flow like type II) and because it is a cheap technique, reducing direct costs and X-ray exposure to the patients. Methods: We started using CEUS as the first-level examination to detect EL in every EVAR patients. CEUS is performed at 3–6–12 months after EVAR and then annually. Computed tomography scan is performed to every patient, to confirm the diagnosis of EL and in any case of sac enlargement without evidence of EL during CEUS. The procedure consists in the administration of 2.5 ml SonoVue® (Bracco Farmaceutici-Milano) bolus followed by 5 ml sodium chloride 0.9% and is performed on Philips IU22 (Philips, Netherlands). We used to start collecting time at the end of the bolus injection. Results: In our 31 patient population, we recorded 13 cases of EL (41.93%), in particular, 3 cases of type I-III (9.68%) and 10 cases of type II (32.25%); in the whole group, sensibility and specificity (Se and Sp) of CEUS to detect EL (not type-specific) were 92% and 100%, respectively. These data are as other data of more important case-series. Conclusions: CEUS is considered the gold standard technique to detect early EL for more authors worldwide. In our experience, we can confirm this matter because CEUS has high Se and Sp (about 100%, in any cases).
Keywords: Contrast-enhanced ultrasound, endoleak, endovascular aneurysm repair, follow-up
|How to cite this article:|
Busoni C, Frigerio D. Contrast-Enhanced ultrasound in endovascular aneurysm repair follow-up: Our experience. Indian J Vasc Endovasc Surg 2020;7:237-40
|How to cite this URL:|
Busoni C, Frigerio D. Contrast-Enhanced ultrasound in endovascular aneurysm repair follow-up: Our experience. Indian J Vasc Endovasc Surg [serial online] 2020 [cited 2020 Sep 27];7:237-40. Available from: http://www.indjvascsurg.org/text.asp?2020/7/3/237/294921
| Background|| |
Endovascular aneurysm repair (EVAR) is actually considered a safe and valid technique in the treatment of abdominal aortic aneurysms (AAAs), particularly because of its low morbidity and mortality in the perioperative period and its reductions of hospital stay, in comparison to the surgical traditional technique. Despite these advantages, EVAR has its own complications, which the most common is endoleak (EL) (10%–20% in most series). EL is defined as the persistence of blood flow in the aneurismal sac, and it is classified into five types: type 1 (a-b-c), type 2, type 3, type 4, and type 5 or endotension [Table 1]; the most frequent EL is type 2 (20%–44%). The most important and prevalent result of EL is an incessant growth of the aneurismal sac and finally its rupture, so any patient who underwent EVAR is strictly monitored with specific tests at 3–6–12 months and then annually (minimum 6 years, EUROSTAR project); the goal of this plan is to find early as possible the diameter increase and in some cases, sketch the treatment out. In the past follow-up was based on computed tomography (CT) scan using X-ray and iodinate-contrast, now the new technologies allow the use of contrast-enhanced ultrasound (CEUS) as first-level examination to detect EL and its consequences, using CT scan only in doubtful cases or to plan interventions. This change in the management of EVAR follow-up is due to the sensibility and specificity (Se and Sp) of CEUS, which is about 67%–100% and 79%–100% respectively, in most series; these events cause a reduction in X-ray exposure, reduction in iodinate-contrast use and renal-toxicity and reduction of total costs.
In this article, we will describe our own experience using CEUS as “gold standard” and first-level examination in EVAR-patients follow-up to detect early EL, confirming sensibility and specificity data.
| Methods|| |
Patients, inclusion and exclusion criteria
This single-center retrospective study (January 2017 –August 2019) includes 31 patients who underwent EVAR from 2017, and informed consent was obtained from all the patients enrolled. Exclusion criteria consisted of the presence of insufficient image quality or the lack of any image study, but nobody was excluded from the study. The population is formed by 28 men and 3 women, mean age 78.6 years (61–100); there are 13 Gore C3 Excluder grafts (2 iliac-branched endografts), 3 Zenith-Cook grafts (2 in monoiliac form), 12 Medtronic Endurant grafts (5 in monoiliac form), and 3 Jotec E-tegra grafts (1 iliac-branched, 1 single E-ventus). None of the patients had allergic diathesis after iodinate or ultrasound contrast injection; only 1 patient had a reduction in aneurysm sac (shrinkage), data confirmed by CEUS and CT scan.
Imaging technique – Contrast-enhanced ultrasound
All ultrasound examinations were performed on a Philips IU22 scanner (Philips, Amsterdam, The Netherlands) with specific software setting (Philips QLAB), convex probes (C5-1), and low acoustic ultrasound pressure without using the color-flow technique. We obtained longitudinal and axial scans, oriented in relation to the aortoiliac major axis. All patients have specific preparation to reduce abdominal gas to have the best images [Table 2]. Each examination started with a B-mode scan to measure the diameter of the sac and to control the correct position of the stents; note is made of the echogenicity of thrombus within the aneurysm sac; using color flow imaging and spectral Doppler, waveform characteristics and velocities are recorded in the common femoral arteries. Then, we administrated 2.5 ml bolus of the second-generation contrast agent (SonoVue®, Bracco, Milan, Italy) in peripheral vein (usually left forearm), followed by 5 ml bolus of saline solution 9%. The on-screen timer is started at the end of the injection. Aorta insonation was continuous with a dynamic observation from the unenhanced to contrast-enhanced phase. During the contrast-enhanced phase, we evaluated the presence of EL, showed by the presence of contrast microbubbles in the aneurysm sac; in the majority of cases, evaluating the direction of the flow and its filling time, we can determine the type of EL, because immediate enhancement would suggest a graft-related type I or III EL whereas a delay of >5 s would suggest a type II EL. Every examination stops after about 6 min, to detect every possible EL, also the later ones (type II, typically). We performed CEUS examination at 3–6–12 months after EVAR, then annually.
Imaging technique – Computed tomography
Abdominal aorta CT scan study was performed with a 64-row scanner (Brilliance CT-64; Philips, The Netherlands) before and after intravenous administration of 1.5 ml/kg of iodine contrast agent (Omnipaque 350, GE Healthcare s. r. l., USA; 130 ml maximum) by automatic injector. Patients underwent a craniocaudal scan from diaphragm to symphysis pubis with a three-phase protocol: noncontrast scan, arterial contrast-scan (4 s delay), and venous-contrast acquisition (60 s delay). CT images were analyzed on a dedicated workstation to generate multiplanar two-dimensional reconstruction, maximum intensity projections and three-dimensional reconstructions (volume rendering); the images were separately evaluated by a radiologist and by a vascular surgeon; in controversial cases, due to classification of EL, radiologists and vascular surgeons worked together to come to a conclusion. We performed CT scan at 3–12 months, then every 2 years.
| Results|| |
In our 31 patient population, everyone underwent both CEUS and CT scan to compare the results, and we recorded 13 cases of EL (41.93%), in particular, 3 cases of type I–III (9.68%) and 10 cases of type II (32.25%); the incidence of EL is higher than in literature because of our small population.
In the whole group, Se and Sp of CEUS to detect EL (not type-specific) were 92% and 100%, respectively.
Type I–III EL was treated by endovascular repair, in 2 cases using proximal cuffs with success and in 1 case the patient refused the treatment (he was elderly, now he was died, but the aneurysm sac was intact). Two of these cases were diagnosed using CEUS and confirmed by CT scan, and 1 was distinguished by CT scan (CEUS was diagnostic for type II EL), then we can say that CEUS has 67% of Se to diagnose type I or III EL, which were the most dangerous complications because of the high incidence of sac rupture in short time.
In type II EL group, we have a miscellaneous cases: 1 is doubt case but the patient refuses diagnostic angiography, 1 was successfully treated with paraendograft injection of Onyx® glue, 1 treated by laparoscopic binding of ischemia-modified albumin [Figure 1] and [Figure 2], 1 was solved by itself, and 6 cases are stable without sac enlargement. In this group, 9 cases of type II EL were detected by CEUS, 1 case had a negative CEUS with sac enlargement and the diagnosis was obtained by CT scan, with a Se of 90% of CEUS in detecting type II EL.
Eighteen patients were, and are now, free of EL complication both in CEUS and CT scan [Figure 3], [Figure 4], [Figure 5], [Figure 6].
| Conclusions|| |
Since EVAR was introduced in clinical practice, it was considered a safe and valid alternative to traditional surgery; although the results were and are excellent in the immediate postoperative period, the medium- and long-term results are under discussion, because of ELs. In the past, CT scan was considered the unique gold standard technique to find EL, but it does not indicate direction of blood flow or provide accurate temporal information and may not be able to classify some EL; actually many studies emphasize the potential role of CEUS as first-level technique to early diagnosis of this potential catastrophic event. In our study, we can confirm the accuracy of CEUS in EVAR follow-up, although it has limitations due to the burden of the echo reflection by the metallic component of the graft, extended calcifications, obesity, low-flow EL, and operator experience; so we now use this technique as fist level examination, using CT scan only to investigate doubt cases or patients with type I–III EL to plan a treatment or patients who have a sac expansion without evidence of EL during CEUS. The limitations of this study include its retrospective nature and small numbers of patients who underwent CEUS, however in our opinion, CEUS can be utilized as safe and effective method in post-EVAR surveillance; with our work, we hope to raise interesting questions about the future of this method around the scientific community, to play a role in technological surgical developments.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2]