Cardiovasc Intervent Radiol DOI 10.1007/s00270-013-0762-4
CLINICAL INVESTIGATION
Inferior Mesenteric Artery Embolization Before Endovascular Aortic Aneurysm Repair Using Amplatzer Vascular Plug Type 4 Rene´ Mu¨ller-Wille • Wibke Uller • Holger Go¨ßmann • Peter Heiss • Philipp Wiggermann • Marco Dollinger • Piotr Kasprzak • Karin Pfister Christian Stroszczynski • Walter A. Wohlgemuth
•
Received: 20 August 2013 / Accepted: 13 September 2013 Ó Springer Science+Business Media New York and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) 2013
Abstract Purpose This study was designed to evaluate the efficacy and safety of Amplatzer Vascular Plug type 4 (AVP-4) for embolization of the inferior mesenteric artery (IMA) before endovascular aneurysm repair (EVAR) of the abdominal aorta to prevent endoleaks. Methods A single-center retrospective review of 31 patients who underwent IMA embolizations before EVAR using the AVP-4 was performed. We analyzed the insertion and detachment procedure, the technical success, and the final position of the plug. Technical success was defined as complete occlusion of the IMA. To compare the incidence of IMA-related type II endoleaks in patients with and without preoperative IMA embolization, we additionally reviewed the course of 43 patients with a preoperatively patent IMA who underwent no IMA embolization. Results Plugs with a diameter of 5, 6, and 8 mm were used in 5 (16.1 %), 21 (67.7 %), and 5 (16.1 %) patients, respectively (50–100 % oversizing). In 29 of 31 patients (93.5 %), we observed complete occlusion of the IMA R. Mu¨ller-Wille (&) W. Uller H. Go¨ßmann P. Heiss P. Wiggermann M. Dollinger C. Stroszczynski W. A. Wohlgemuth Department of Radiology, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany e-mail: [email protected] W. Uller e-mail: [email protected]
within 10 min (mean 5.1 min). Precise placement of the plug in the proximal segment of the IMA without occlusion of the first IMA branches was achievable in all patients. The distance between the AVP-4 and the first branches was on average 12 (range 2–57) mm. Preoperative IMA embolization with AVP-4 significantly reduced the incidence of complex IMA-lumbar type II endoleaks after EVAR (0/31 vs. 11/43; p = 0.002). Conclusions The AVP-4 is a safe, feasible, and technically effective embolization device for IMA embolization before EVAR. Keywords Arterial intervention Embolization Endovascular aneurysm repair Abdominal aortic aneurysm (AAA) Introduction Endovascular aneurysm repair (EVAR) is an accepted alternative to open surgery in the treatment of abdominal M. Dollinger e-mail: [email protected] C. Stroszczynski e-mail: [email protected] W. A. Wohlgemuth e-mail: [email protected]
H. Go¨ßmann e-mail: [email protected]
P. Kasprzak K. Pfister Department of Surgery, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, Regensburg, Germany e-mail: [email protected]
P. Heiss e-mail: [email protected]
K. Pfister e-mail: [email protected]
P. Wiggermann e-mail: [email protected]
123
R. Mu¨ller-Wille et al.: IMA Embolization Using AVP-4
aortic aneurysms (AAA). One potential drawback is the occurrence of type II endoleaks after EVAR. This type of endoleak is defined as retrograde blood flow through aortic branch vessels into the perigraft space, occurring in 10–25 % of patients after EVAR [1]. Backflow through the inferior mesenteric artery (IMA) can transmit systemic pressures into the aneurysm sac [2], and it has been shown that persistent type II endoleaks were significantly associated with aneurysm sac growth and a high incidence of secondary interventions [3]. On preoperative CT scans, the IMA is patent in up to 76 % [4] of cases and it turned out that patients with a preoperative patent IMA had a significantly higher risk of developing a type II endoleak [4–8]. There is some evidence that preoperative or intraoperative coil embolization of a patent IMA reduces the development of type II endoleaks [9–14]. Recently, Ward et al. [14] demonstrated that preoperative coil embolization of the IMA in 108 patients was associated significantly with reduced aneurysm sac volume enlargement at 24 months and secondary intervention. One concern against preoperative IMA embolization, however, is the risk of intestinal ischemia. To prevent ischemic complications, the trunk of the IMA has to be embolized, leaving the left colic artery (LCA) and superior rectal artery (SRA) open to preserve the blood supply of the rectum and sigmoid colon. Therefore, a precise and safe embolization technique of the IMA trunk is essential. The newly introduced Amplatzer Vascular Plug type 4 (AVP-4, St. Jude Medical, Plymouth, MN, USA) offers a controllable alternative to classical coils [15–21]. The AVP-4 is a self-expanding nitinol wire mesh derived from the Amplatzer septal occluder. The multilayered and double-lobed design of the plug induces rapid thrombosis after deployment. In contrast to the larger AVP-II, the AVP-4 is delivered through a 4-F or 5-F diagnostic catheter with a 0.038-inch minimum inner lumen. This low-profile made the AVP-4 suitable for embolization of the IMA via a standard diagnostic catheter. We summarize our initial technical experience with the AVP-4 for preoperative embolizations of the IMA in patients undergoing EVAR of the abdominal aorta.
Materials and Methods Patients We conducted a retrospective study of 31 patients who underwent IMA embolization before EVAR using the AVP-4 between July 2011 and July 2013 (all male patients; mean age 69 years; age range 51–83 years). Preoperative embolization of a patent IMA was part of our regular patient preparation before elective EVAR of AAA. Patients characteristics are summarized in Table 1.
123
Embolization Technique Twenty-eight procedures (90.3 %) were performed under local anesthesia in our angiography suite and three (9.7 %) under general anesthesia in our hybrid operating room immediately before EVAR. Depending on the individual anatomy of the patient (i.e., steep vs. flat downward angle of the IMA-origin) embolization was performed via right femoral artery or left brachial artery approach. A 0.035inch hydrophilic guidewire (Radifocus, Terumo, Tokyo, Japan) and a 4-F or 5-F diagnostic catheter with a 0.038inch inner lumen (e.g., 4-F Vertebralis, Cordis, Miami Lakes, FL, USA) were used for selective catheterization. Before catheterization of the IMA, an angiogram of the superior mesenteric artery (SMA) was performed to ensure a sufficient collateral blood flow via Riolan’s anastomosis (Fig. 1). The distal tip of the diagnostic catheter was then placed into the proximal segment of the IMA and another angiogram was performed to evaluate the exact anatomy of the IMA (Fig. 2). The guidewire was removed and the AVP-4 was passed through into the tip of the catheter. We used plugs with a diameter between 5 and 8 mm depending on the diameter of the IMA. We intended an oversizing of 50–100 %. The purpose was to place the plug in the proximal segment of the IMA not to occlude the bifurcation of LCA and SRA (Fig. 1). The device had a radiopaque marker band at each end to ensure good visibility. When the device was placed appropriately, the diagnostic catheter was retracted slowly under fluoroscopy to deploy the plug. If the position of the plug was suboptimal on first attempt, the device was retracted and repositioned. The plug, connected with a microscrew attachment at the end of the 155-cm PTFE-coated delivery wire, was released by
Table 1 Patients (n = 31) n
(%)
Diseases Infrarenal aortic aneurysm
21
(67.7)
Infrarenal aortic aneurysm and iliac artery aneurysm
7
(22.6)
Juxtarenal aortic aneurysm
1
(3.2)
Penetrating atherosclerotic ulcer
1
(3.2)
Dissecting aortic aneurysm
1
(3.2)
22
(71)
Stent-graft type Aortobiiliac stent-graft Aortobiiliac stent-graft and fenestrated/branched
7
(22.6)
Aortouniiliac stent-graft
1
(3.2)
Aortic stent-graft
1
(3.2)
Cook (Zenith)
19
(61.3)
Gore (Excluder)
12
(38.7)
Stent-graft manufactures
R. Mu¨ller-Wille et al.: IMA Embolization Using AVP-4
counterclockwise rotation of the delivery wire. An angiogram was performed after detachment of the plug to prove occlusion of the IMA. Finally, we again performed an angiogram of the SMA to control the perfusion of the LCA and SRA via Riolan’s anastomosis. Evaluation of Technical Success Technical success was defined as the complete occlusion of the IMA on the final angiogram and the absence of IMArelated type II endoleaks on contrast-enhanced postoperative CT scans (Fig. 3). We routinely performed a triplephase CT scan (noncontrast, arterial phase, delayed phase)
within the first 30 days after EVAR. A dual-source CT scanner (Somatom Definition Flash, Siemens, Forchheim, Germany) was used for all examinations. Contrastenhanced images were obtained during the injection of 90 mL of contrast medium (Ultravist 370, Bayer HealthCare Pharmaceuticals, Berlin, Germany) at a flow rate of 4 mL sec-1. An IMA-related type II endoleak was defined as a continuous area of contrast-enhancement from the IMA into the aneurysm sac. To assess the final position of the released plug, we retrospectively measured the length of the IMA and of the AVP-4, as well as the distance from plug to the first branches of the IMA (Fig. 4). All measurements were done
Fig. 1 This 69-year-old man had an incidental finding of an abdominal aortic aneurysm measuring 5.8 cm. A Selective superior mesenteric artery (SMA) arteriogram before IMA embolizations using a 5-mm AVP-4 shows a patent left branch (black arrowheads) of the middle colic artery (MCA) in the splenic flexure region. B Selective inferior mesenteric artery (IMA) arteriogram
demonstrates the left colic artery (LCA), which has an ascending division that anastomoses with the left branch of the middle colic artery (black arrowheads). C Contrast-enhanced CT after IMA embolization (AVP-4) and EVAR showed perfusion of the superior rectal artery (SRA) via the SMA-IMA anastomosis (white arrows)
Fig. 2 Embolization technique. A Selective angiogram of the inferior mesenteric artery. B The diagnostic catheter was placed in the trunk of the IMA (IMA inferior mesenteric artery, LCA left colic artery, SA sigmoid arteries, SRA superior rectal artery). C Insertion of the constrained AVP-4 through the diagnostic catheter. D Deployment of
the AVP-4 in the proximal segment of the IMA by retracting the diagnostic catheter (arrow). E Detachment of the AVP-4 by counterclockwise rotation of the delivery wire (arrow). F Extraction of the delivery wire and release of the plug
123
R. Mu¨ller-Wille et al.: IMA Embolization Using AVP-4
Fig. 3 Technically successful IMA embolization before EVAR of an abdominal aortic aneurysm using a single AVP-4. A Transbrachial catheterization of the IMA using a 4-F diagnostic catheter (vertebralis, cordis). B The AVP-4 (8 mm) was inserted through the diagnostic catheter and released by counterclockwise rotation of the
delivery wire. C Final angiogram showed complete occlusion of the proximal IMA. D Contrast-enhanced CT angiogram after EVAR showed a technically successful IMA embolization using AVP-4. IMA-related type II endoleak was not detected
defined by SIR classification system for complications by outcome [22]. Comparison with Control Group To compare the incidence of IMA-related type II endoleaks in patients with and without preoperative IMA embolization, we reviewed the course of all patients who underwent elective EVAR for AAA between January 2008 and January 2010 (70 patients). Forty-three patients (43/70; 61.4 %) with preoperative patent IMA served as control group (mean age 73 years; range 61–85 years). Differences between both groups were tested for statistical significance using Fisher’s exact test (two-tailed).
Results
Fig. 4 Evaluation of plug position. Curved planar reformation (CPR) images were obtained along the course of the IMA before embolization (A) and after EVAR (B). L length of the IMA, P length of the plug, D distance between the AVP-4 and the first branches of the IMA, LCA left colic artery, SRA superior rectal artery
on curved planar reformation images of the IMA computed from the contrast-enhanced CT data sets (SyngoVia, CTvascular, Siemens, Forchheim, Germany). Procedure-Related Complications We evaluated retrospectively the incidence of procedurerelated complications. Minor and major complications were
123
Embolization of the IMA was performed on average 17 (range 0–134) days before EVAR. In most cases (26/31, 83.9 %), the left brachial artery approach was used. In two cases (6.5 %), the origin of the IMA was heavily calcified and insertion of a 4-F diagnostic catheter was primary not achievable. Therefore, the calcified ostium of these two patients was dilated with a 4-mm low-profile balloon to make the IMA accessible for the diagnostic catheter. In most cases, the contrast-enhanced lumen of the IMA had a diameter of 3 mm (17/31, 54.8 %), followed by 4 mm (12/31, 38.7 %) and 5 mm (2/31, 6.5 %). Patients with an IMA diameter of 3 and 4 mm most often were embolized with a 6-mm AVP-4 (12/15, 70.6 %; 9/12, 75 %). In the two patients with an IMA diameter of 5 mm, we used the 8-mm AVP-4 (Table 2). The selected plugs were oversized by 50–100 % (mean 77.5 %).
R. Mu¨ller-Wille et al.: IMA Embolization Using AVP-4 Table 2 Diameter of the IMA and the released AVP-4 in 31 patients IMA diameter
AVP-4 diameter 5 mm
6 mm
8 mm
3 mm
5
12
0
17
4 mm
0
9
3
12
5 mm
0
0
2
2
5
21
5
IMA inferior mesenteric artery, AVP-4 Amplatzer Vascular Plug type 4
The plug was released without any complication by rotating the delivery wire counterclockwise in all cases. We observed no plug migration after detachment. Occlusion of the IMA was achieved in 29 of 31 patients (93.5 %) within 10 (mean, 5.1) minutes after deployment of the plug (Fig. 3). In two cases, additional embolization with Gelfoam was performed to achieve complete occlusion in the same session. Finally, angiographic occlusion of the IMA was documented in each case. Technical success was achieved in all patients (100 %). Retrospective analyses of the postoperative CT scans showed that the plug was placed correctly in the proximal segment of the IMA without occlusion of the IMA branches in all cases. The distance between the distal marker band of the AVP-4 and the first branches of the IMA was on average 12 (range 2–57) mm. The mean length of the IMA was 35 (range 18–64) mm (Fig. 5). The lengths of the released 5, 6, and 8-mm AVP-4 were on average 13 (range 12–14) mm, 16 (range 13–18) mm, and 23 (range 20–25) mm, respectively. In two patients (6.5 %), the proximal marker band of the AVP-4 protruded slightly into the aortic lumen. In both cases, the plug was released via a right femoral artery approach. The steep angle of the diagnostic catheter prevented a deeper insertion of the plug. We observed no nontarget embolization, rectosigmoid ischemia, dissections, stroke (in cases of brachial artery approach), or death in the period between IMA embolization and EVAR. Two (6.5 %) puncture site hematomas occurred. All embolized patients underwent contrast-enhanced CT scans within 30 days after EVAR (mean 6 days; range 1–26 days). We identified no IMA-related early type II endoleaks. There were one type I endoleak (1/31; 3.2 %), one type III endoleak (1/31; 3.2 %), and six (6/31; 19.4 %) early type II endoleaks. All type II endoleaks were small and attributed to a retrograde flow from lumbar arteries, mostly fourth lumbar arteries (5/6; 83.3 %). Three patients with early lumbar type II endoleak had follow-up for more than 6 months available (range 7–10 months). Aneurysm sac size was stable in two and decreased in one patient.
Fig. 5 Length of the IMA in 31 patients
In the control group, we observed four type I endoleaks (4/43; 9.3 %) and 14 early type II endoleaks (14/43; 32.6 %). Most of these type II endoleaks were complex IMA-lumbar type II endoleaks (11/14; 78.6 %); three (3/14; 21.4 %) patients had lumbar type II endoleaks. Twelve patients with early-type II endoleaks (12/14; 85.7 %) had follow-up data for more than 6 months available [mean 26 (range 9–47) months]. Eight patients—all with a complex IMA-lumbar type II endoleak—showed a significant aneurysm sac enlargement (C5 % volume increase) during follow-up. In comparison, preoperative IMA embolization significantly reduced the incidence of early complex IMAlumbar type II endoleaks after EVAR (0/31 vs. 11/43; p = 0.002). The incidence of lumbar type II endoleaks was comparable in both groups (6/31 vs. 3/43; p = 0.15).
Discussion The low-profile design of the AVP-4 eliminates the need for large-lumen guiding catheters or sheaths compared with its larger precursor AVP-II, enabling the deployment of the plug in smaller arteries. Since its introduction, several reports and case series described the use of the AVP-4 for the embolization of arteriovenous fistulas [15], treatment of pseudoaneurysms and hemorrhages [16–19], occlusions of aneurysms [17, 19, 20], and for preparation before selective internal radiotherapy [19, 21]. Up to now, IMA embolization before EVAR using the AVP-4 has been reported only by Mordasini (two patients) [17] and Pech (three patients) [19].
123
R. Mu¨ller-Wille et al.: IMA Embolization Using AVP-4
The optimal device for preoperative IMA embolizations should safely occlude the vessel and should be short enough to allow collateral perfusion of the IMA branches. Our data supported the impression that the AVP-4 is an effective and safe device for IMA embolizations before EVAR. Occlusion of the IMA was achieved on average 5 min after placement of a single AVP-4. In two patients, occlusion time was longer than 10 min, thus additional Gelfoam embolization was performed. It is possible that occlusion would have occurred without Gelfoam as well. Plug oversizing between 50 and 100 % provided a secure fixation of the plug in all cases. Unlike the description by Pech et al. [19], we had no problems in disconnecting the plug. The released AVP-4 was short enough to ensure an adequate distance between the plug and the first branches of the IMA. In most cases, the 6-mm AVP-4 was used, which had a mean length of 16 mm after detachment. In the present study, the measured length of IMA matched with the reported range of 2–7 (mean 3.5) cm based on dissections of adult cadavers [23]. Furthermore, the possibility of angiography before final plug detachment through the delivery catheter provides additional security. If the position of the AVP-4 is suboptimal, the device can be retracted and repositioned. In most cases, we used a transbrachial access for IMA embolization, because the IMA runs in most cases steeply downwards and a straight catheter position was preferable for a safe and stable positioning of the relatively stiff device. In our series, embolization via the femoral approach was technically possible but more difficult, and in two cases, the plug protruded slightly into the aortic lumen. Mordasini et al. [17] describe an unsuccessful IMA embolization with an AVP-4 via a femoral approach as a result of repeated catheter tip dislocation. Similarly Muthu et al. [11] reported that transfemoral coil embolization of the IMA failed because of unstable catheter position. All previous studies used coils for IMA embolization before EVAR [9, 10, 12–14]. Up to now, no studies have compared the AVP-4 with coils in this setting regarding technical success, procedural time, radiation dose, and costs. Nevertheless, it has been shown that the precursor AVP-II had advantages over coils for selective embolization of larger arteries. In a randomized trial, the embolization of the gastroduodenal artery before internal radiotherapy using the AVP-II was associated with a shorter duration of the procedure, shorter embolization times, and less exposure to radiation [24]. Furthermore, the material cost for embolization was approximately 30 % lower with the AVP-II than with coil embolization [24]. It has recently been published that the risk of bowel ischemia after coil embolizations of the IMA is \1 % [14]. Nevertheless, we deem it absolutely necessary to perform a selective angiogram of the SMA to evaluate the collateral blood flow through Riolan’s arcade before occluding the IMA trunk regardless with which material.
123
We observed a relatively high incidence of lumbar type II endoleaks in our embolized patient group. However, the incidence of lumbar type II endoleaks was statistically not different to our control group. It shall be taken into account that preoperative IMA embolization significantly reduced the incidence of complex IMA-lumbar type II endoleaks, which had more clinical significance than small lumbar endoleaks, hence most control patients with complex IMAlumbar endoleaks showed aneurysm sac enlargement during follow-up. One major drawback of our study is that not all patients have follow-up data (more than 6 months) available to date due to the recent data set. Thus, incidence of late onset IMA-related type II endoleaks and aneurysm size changes were not evaluable. Furthermore, randomized studies are warranted to compare the AVP-4 with coils in this setting.
Conclusions The AVP-4 is a safe and effective embolization device for selective IMA embolization before EVAR. Conflict of interest of interest.
The authors declare that they have no conflict
References 1. Veith FJ, Baum RA, Ohki T et al (2002) Nature and significance of endoleaks and endotension: summary of opinions expressed at an international conference. J Vasc Surg 35:1029–1035 2. Velazquez OC, Baum RA, Carpenter JP et al (2000) Relationship between preoperative patency of the inferior mesenteric artery and subsequent occurrence of type II endoleak in patients undergoing endovascular repair of abdominal aortic aneurysms. J Vasc Surg 32(4):777–788 3. Jones JE, Atkins MD, Brewster DC et al (2007) Persistent type 2 endoleak after endovascular repair of abdominal aortic aneurysm is associated with adverse late outcomes. J Vasc Surg 46(1):1–8 4. Sampaio SM, Panneton JM, Mozes GI et al (2005) Aneurysm sac thrombus load predicts type II endoleaks after endovascular aneurysm repair. Ann Vasc Surg 19(3):302–309 5. Fan CM, Rafferty EA, Geller SC et al (2001) Endovascular stentgraft in abdominal aortic aneurysms: the relationship between patent vessels that arise from the aneurysmal sac and early endoleak. Radiology 218(1):176–182 6. Abularrage CJ, Crawford RS, Conrad MF et al (2010) Preoperative variables predict persistent type 2 endoleak after endovascular aneurysm repair. J Vasc Surg 52(1):19–24 7. AbuRahma AF, Mousa AY, Campbell JE et al (2011) The relationship of preoperative thrombus load and location to the development of type II endoleak and sac regression. J Vasc Surg 53(6):1534–1541 8. Brountzos E, Karagiannis G, Panagiotou I et al (2012) Risk factors for the development of persistent type II endoleaks after endovascular repair of infrarenal abdominal aortic aneurysms. Diagn Interv Radiol 18(3):307–313
R. Mu¨ller-Wille et al.: IMA Embolization Using AVP-4 9. Axelrod DJ, Lookstein RA, Guller J et al (2004) Inferior mesenteric artery embolization before endovascular aneurysm repair: technique and initial results. J Vasc Interv Radiol 15(11):1263–1267 10. Bonvini R, Alerci M, Antonucci F et al (2003) Preoperative embolization of collateral side branches: a valid means to reduce type II endoleaks after endovascular AAA repair. J Endovasc Ther 10(2):227–232 11. Muthu C, Maani J, Plank LD et al (2007) Strategies to reduce the rate of type II endoleaks: routine intraoperative embolization of the inferior mesenteric artery and thrombin injection into the aneurysm sac. J Endovasc Ther 14(5):661–668 12. Nevala T, Biancari F, Manninen H et al (2010) Inferior mesenteric artery embolization before endovascular repair of an abdominal aortic aneurysm: effect on type II endoleak and aneurysm shrinkage. J Vasc Interv Radiol 21(2):181–185 13. Parry DJ, Kessel DO, Robertson I et al (2002) Type II endoleaks: predictable, preventable, and sometimes treatable? J Vasc Surg 36(1):105–110 14. Ward TJ, Cohen S, Fischman AM et al (2013) Preoperative inferior mesenteric artery embolization before endovascular aneurysm repair: decreased incidence of type II endoleak and aneurysm sac enlargement with 24-month follow-up. J Vasc Interv Radiol 24(1):49–55 15. Buttarelli L, Capocasale E, Marcato C et al (2011) Embolization of pancreatic allograft arteriovenous fistula with the Amplatzer Vascular Plug 4: case report and literature analysis. Transplant Proc 43(10):4044–4047 16. Ferro C, Rossi UG, Bovio G et al (2010) The Amplatzer Vascular Plug 4: preliminary experience. Cardiovasc Interv Radiol 33(4):844–848
17. Mordasini P, Szucs-Farkas Z, Do DD et al (2010) Use of a latestgeneration vascular plug for peripheral vascular embolization with use of a diagnostic catheter: preliminary clinical experience. J Vasc Interv Radiol 21(8):1185–1190 18. Ng EH, Comin J, David E et al (2012) Amplatzer vascular plug 4 for proximal splenic artery embolization in blunt trauma. J Vasc Interv Radiol 23(7):976–979 19. Pech M, Mohnike K, Wieners G et al (2011) Advantages and disadvantages of the Amplatzer Vascular Plug IV in visceral embolization: report of 50 placements. Cardiovasc Interv Radiol 34(5):1069–1073 20. Rossi UG, Seitun S, Ferro C (2013) Endovascular embolization of a third jejunal artery aneurysm: isolation technique using the Amplatzer Vascular Plug 4. Catheter Cardiovasc Interv 81(6): 1049–1052 21. Yildiz AE, Peynircioglu B, Cil BE (2012) Applications of the Amplatzer Vascular Plug 4. Diagn Interv Radiol 18(2):225–230 22. Sacks D, McClenny TE, Cardella JF et al (2003) Society of interventional radiology clinical practice guidelines. J Vasc Interv Radiol 14(9 Pt 2):S199–S202 23. Michels NA, Siddharth P, Kornblith PL et al (1965) The variant blood supply to the descending colon, rectosigmoid and rectum based on 400 dissections. Its importance in regional resections—a review of medical literature. Dis Colon Rectum 8:251–278 24. Pech M, Kraetsch A, Wieners G et al (2009) Embolization of the gastroduodenal artery before selective internal radiotherapy: a prospectively randomized trial comparing platinum-fibered microcoils with the Amplatzer Vascular Plug II. Cardiovasc Interv Radiol 32(3):455–461
123
CLINICAL INVESTIGATION
Inferior Mesenteric Artery Embolization Before Endovascular Aortic Aneurysm Repair Using Amplatzer Vascular Plug Type 4 Rene´ Mu¨ller-Wille • Wibke Uller • Holger Go¨ßmann • Peter Heiss • Philipp Wiggermann • Marco Dollinger • Piotr Kasprzak • Karin Pfister Christian Stroszczynski • Walter A. Wohlgemuth
•
Received: 20 August 2013 / Accepted: 13 September 2013 Ó Springer Science+Business Media New York and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) 2013
Abstract Purpose This study was designed to evaluate the efficacy and safety of Amplatzer Vascular Plug type 4 (AVP-4) for embolization of the inferior mesenteric artery (IMA) before endovascular aneurysm repair (EVAR) of the abdominal aorta to prevent endoleaks. Methods A single-center retrospective review of 31 patients who underwent IMA embolizations before EVAR using the AVP-4 was performed. We analyzed the insertion and detachment procedure, the technical success, and the final position of the plug. Technical success was defined as complete occlusion of the IMA. To compare the incidence of IMA-related type II endoleaks in patients with and without preoperative IMA embolization, we additionally reviewed the course of 43 patients with a preoperatively patent IMA who underwent no IMA embolization. Results Plugs with a diameter of 5, 6, and 8 mm were used in 5 (16.1 %), 21 (67.7 %), and 5 (16.1 %) patients, respectively (50–100 % oversizing). In 29 of 31 patients (93.5 %), we observed complete occlusion of the IMA R. Mu¨ller-Wille (&) W. Uller H. Go¨ßmann P. Heiss P. Wiggermann M. Dollinger C. Stroszczynski W. A. Wohlgemuth Department of Radiology, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany e-mail: [email protected] W. Uller e-mail: [email protected]
within 10 min (mean 5.1 min). Precise placement of the plug in the proximal segment of the IMA without occlusion of the first IMA branches was achievable in all patients. The distance between the AVP-4 and the first branches was on average 12 (range 2–57) mm. Preoperative IMA embolization with AVP-4 significantly reduced the incidence of complex IMA-lumbar type II endoleaks after EVAR (0/31 vs. 11/43; p = 0.002). Conclusions The AVP-4 is a safe, feasible, and technically effective embolization device for IMA embolization before EVAR. Keywords Arterial intervention Embolization Endovascular aneurysm repair Abdominal aortic aneurysm (AAA) Introduction Endovascular aneurysm repair (EVAR) is an accepted alternative to open surgery in the treatment of abdominal M. Dollinger e-mail: [email protected] C. Stroszczynski e-mail: [email protected] W. A. Wohlgemuth e-mail: [email protected]
H. Go¨ßmann e-mail: [email protected]
P. Kasprzak K. Pfister Department of Surgery, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, Regensburg, Germany e-mail: [email protected]
P. Heiss e-mail: [email protected]
K. Pfister e-mail: [email protected]
P. Wiggermann e-mail: [email protected]
123
R. Mu¨ller-Wille et al.: IMA Embolization Using AVP-4
aortic aneurysms (AAA). One potential drawback is the occurrence of type II endoleaks after EVAR. This type of endoleak is defined as retrograde blood flow through aortic branch vessels into the perigraft space, occurring in 10–25 % of patients after EVAR [1]. Backflow through the inferior mesenteric artery (IMA) can transmit systemic pressures into the aneurysm sac [2], and it has been shown that persistent type II endoleaks were significantly associated with aneurysm sac growth and a high incidence of secondary interventions [3]. On preoperative CT scans, the IMA is patent in up to 76 % [4] of cases and it turned out that patients with a preoperative patent IMA had a significantly higher risk of developing a type II endoleak [4–8]. There is some evidence that preoperative or intraoperative coil embolization of a patent IMA reduces the development of type II endoleaks [9–14]. Recently, Ward et al. [14] demonstrated that preoperative coil embolization of the IMA in 108 patients was associated significantly with reduced aneurysm sac volume enlargement at 24 months and secondary intervention. One concern against preoperative IMA embolization, however, is the risk of intestinal ischemia. To prevent ischemic complications, the trunk of the IMA has to be embolized, leaving the left colic artery (LCA) and superior rectal artery (SRA) open to preserve the blood supply of the rectum and sigmoid colon. Therefore, a precise and safe embolization technique of the IMA trunk is essential. The newly introduced Amplatzer Vascular Plug type 4 (AVP-4, St. Jude Medical, Plymouth, MN, USA) offers a controllable alternative to classical coils [15–21]. The AVP-4 is a self-expanding nitinol wire mesh derived from the Amplatzer septal occluder. The multilayered and double-lobed design of the plug induces rapid thrombosis after deployment. In contrast to the larger AVP-II, the AVP-4 is delivered through a 4-F or 5-F diagnostic catheter with a 0.038-inch minimum inner lumen. This low-profile made the AVP-4 suitable for embolization of the IMA via a standard diagnostic catheter. We summarize our initial technical experience with the AVP-4 for preoperative embolizations of the IMA in patients undergoing EVAR of the abdominal aorta.
Materials and Methods Patients We conducted a retrospective study of 31 patients who underwent IMA embolization before EVAR using the AVP-4 between July 2011 and July 2013 (all male patients; mean age 69 years; age range 51–83 years). Preoperative embolization of a patent IMA was part of our regular patient preparation before elective EVAR of AAA. Patients characteristics are summarized in Table 1.
123
Embolization Technique Twenty-eight procedures (90.3 %) were performed under local anesthesia in our angiography suite and three (9.7 %) under general anesthesia in our hybrid operating room immediately before EVAR. Depending on the individual anatomy of the patient (i.e., steep vs. flat downward angle of the IMA-origin) embolization was performed via right femoral artery or left brachial artery approach. A 0.035inch hydrophilic guidewire (Radifocus, Terumo, Tokyo, Japan) and a 4-F or 5-F diagnostic catheter with a 0.038inch inner lumen (e.g., 4-F Vertebralis, Cordis, Miami Lakes, FL, USA) were used for selective catheterization. Before catheterization of the IMA, an angiogram of the superior mesenteric artery (SMA) was performed to ensure a sufficient collateral blood flow via Riolan’s anastomosis (Fig. 1). The distal tip of the diagnostic catheter was then placed into the proximal segment of the IMA and another angiogram was performed to evaluate the exact anatomy of the IMA (Fig. 2). The guidewire was removed and the AVP-4 was passed through into the tip of the catheter. We used plugs with a diameter between 5 and 8 mm depending on the diameter of the IMA. We intended an oversizing of 50–100 %. The purpose was to place the plug in the proximal segment of the IMA not to occlude the bifurcation of LCA and SRA (Fig. 1). The device had a radiopaque marker band at each end to ensure good visibility. When the device was placed appropriately, the diagnostic catheter was retracted slowly under fluoroscopy to deploy the plug. If the position of the plug was suboptimal on first attempt, the device was retracted and repositioned. The plug, connected with a microscrew attachment at the end of the 155-cm PTFE-coated delivery wire, was released by
Table 1 Patients (n = 31) n
(%)
Diseases Infrarenal aortic aneurysm
21
(67.7)
Infrarenal aortic aneurysm and iliac artery aneurysm
7
(22.6)
Juxtarenal aortic aneurysm
1
(3.2)
Penetrating atherosclerotic ulcer
1
(3.2)
Dissecting aortic aneurysm
1
(3.2)
22
(71)
Stent-graft type Aortobiiliac stent-graft Aortobiiliac stent-graft and fenestrated/branched
7
(22.6)
Aortouniiliac stent-graft
1
(3.2)
Aortic stent-graft
1
(3.2)
Cook (Zenith)
19
(61.3)
Gore (Excluder)
12
(38.7)
Stent-graft manufactures
R. Mu¨ller-Wille et al.: IMA Embolization Using AVP-4
counterclockwise rotation of the delivery wire. An angiogram was performed after detachment of the plug to prove occlusion of the IMA. Finally, we again performed an angiogram of the SMA to control the perfusion of the LCA and SRA via Riolan’s anastomosis. Evaluation of Technical Success Technical success was defined as the complete occlusion of the IMA on the final angiogram and the absence of IMArelated type II endoleaks on contrast-enhanced postoperative CT scans (Fig. 3). We routinely performed a triplephase CT scan (noncontrast, arterial phase, delayed phase)
within the first 30 days after EVAR. A dual-source CT scanner (Somatom Definition Flash, Siemens, Forchheim, Germany) was used for all examinations. Contrastenhanced images were obtained during the injection of 90 mL of contrast medium (Ultravist 370, Bayer HealthCare Pharmaceuticals, Berlin, Germany) at a flow rate of 4 mL sec-1. An IMA-related type II endoleak was defined as a continuous area of contrast-enhancement from the IMA into the aneurysm sac. To assess the final position of the released plug, we retrospectively measured the length of the IMA and of the AVP-4, as well as the distance from plug to the first branches of the IMA (Fig. 4). All measurements were done
Fig. 1 This 69-year-old man had an incidental finding of an abdominal aortic aneurysm measuring 5.8 cm. A Selective superior mesenteric artery (SMA) arteriogram before IMA embolizations using a 5-mm AVP-4 shows a patent left branch (black arrowheads) of the middle colic artery (MCA) in the splenic flexure region. B Selective inferior mesenteric artery (IMA) arteriogram
demonstrates the left colic artery (LCA), which has an ascending division that anastomoses with the left branch of the middle colic artery (black arrowheads). C Contrast-enhanced CT after IMA embolization (AVP-4) and EVAR showed perfusion of the superior rectal artery (SRA) via the SMA-IMA anastomosis (white arrows)
Fig. 2 Embolization technique. A Selective angiogram of the inferior mesenteric artery. B The diagnostic catheter was placed in the trunk of the IMA (IMA inferior mesenteric artery, LCA left colic artery, SA sigmoid arteries, SRA superior rectal artery). C Insertion of the constrained AVP-4 through the diagnostic catheter. D Deployment of
the AVP-4 in the proximal segment of the IMA by retracting the diagnostic catheter (arrow). E Detachment of the AVP-4 by counterclockwise rotation of the delivery wire (arrow). F Extraction of the delivery wire and release of the plug
123
R. Mu¨ller-Wille et al.: IMA Embolization Using AVP-4
Fig. 3 Technically successful IMA embolization before EVAR of an abdominal aortic aneurysm using a single AVP-4. A Transbrachial catheterization of the IMA using a 4-F diagnostic catheter (vertebralis, cordis). B The AVP-4 (8 mm) was inserted through the diagnostic catheter and released by counterclockwise rotation of the
delivery wire. C Final angiogram showed complete occlusion of the proximal IMA. D Contrast-enhanced CT angiogram after EVAR showed a technically successful IMA embolization using AVP-4. IMA-related type II endoleak was not detected
defined by SIR classification system for complications by outcome [22]. Comparison with Control Group To compare the incidence of IMA-related type II endoleaks in patients with and without preoperative IMA embolization, we reviewed the course of all patients who underwent elective EVAR for AAA between January 2008 and January 2010 (70 patients). Forty-three patients (43/70; 61.4 %) with preoperative patent IMA served as control group (mean age 73 years; range 61–85 years). Differences between both groups were tested for statistical significance using Fisher’s exact test (two-tailed).
Results
Fig. 4 Evaluation of plug position. Curved planar reformation (CPR) images were obtained along the course of the IMA before embolization (A) and after EVAR (B). L length of the IMA, P length of the plug, D distance between the AVP-4 and the first branches of the IMA, LCA left colic artery, SRA superior rectal artery
on curved planar reformation images of the IMA computed from the contrast-enhanced CT data sets (SyngoVia, CTvascular, Siemens, Forchheim, Germany). Procedure-Related Complications We evaluated retrospectively the incidence of procedurerelated complications. Minor and major complications were
123
Embolization of the IMA was performed on average 17 (range 0–134) days before EVAR. In most cases (26/31, 83.9 %), the left brachial artery approach was used. In two cases (6.5 %), the origin of the IMA was heavily calcified and insertion of a 4-F diagnostic catheter was primary not achievable. Therefore, the calcified ostium of these two patients was dilated with a 4-mm low-profile balloon to make the IMA accessible for the diagnostic catheter. In most cases, the contrast-enhanced lumen of the IMA had a diameter of 3 mm (17/31, 54.8 %), followed by 4 mm (12/31, 38.7 %) and 5 mm (2/31, 6.5 %). Patients with an IMA diameter of 3 and 4 mm most often were embolized with a 6-mm AVP-4 (12/15, 70.6 %; 9/12, 75 %). In the two patients with an IMA diameter of 5 mm, we used the 8-mm AVP-4 (Table 2). The selected plugs were oversized by 50–100 % (mean 77.5 %).
R. Mu¨ller-Wille et al.: IMA Embolization Using AVP-4 Table 2 Diameter of the IMA and the released AVP-4 in 31 patients IMA diameter
AVP-4 diameter 5 mm
6 mm
8 mm
3 mm
5
12
0
17
4 mm
0
9
3
12
5 mm
0
0
2
2
5
21
5
IMA inferior mesenteric artery, AVP-4 Amplatzer Vascular Plug type 4
The plug was released without any complication by rotating the delivery wire counterclockwise in all cases. We observed no plug migration after detachment. Occlusion of the IMA was achieved in 29 of 31 patients (93.5 %) within 10 (mean, 5.1) minutes after deployment of the plug (Fig. 3). In two cases, additional embolization with Gelfoam was performed to achieve complete occlusion in the same session. Finally, angiographic occlusion of the IMA was documented in each case. Technical success was achieved in all patients (100 %). Retrospective analyses of the postoperative CT scans showed that the plug was placed correctly in the proximal segment of the IMA without occlusion of the IMA branches in all cases. The distance between the distal marker band of the AVP-4 and the first branches of the IMA was on average 12 (range 2–57) mm. The mean length of the IMA was 35 (range 18–64) mm (Fig. 5). The lengths of the released 5, 6, and 8-mm AVP-4 were on average 13 (range 12–14) mm, 16 (range 13–18) mm, and 23 (range 20–25) mm, respectively. In two patients (6.5 %), the proximal marker band of the AVP-4 protruded slightly into the aortic lumen. In both cases, the plug was released via a right femoral artery approach. The steep angle of the diagnostic catheter prevented a deeper insertion of the plug. We observed no nontarget embolization, rectosigmoid ischemia, dissections, stroke (in cases of brachial artery approach), or death in the period between IMA embolization and EVAR. Two (6.5 %) puncture site hematomas occurred. All embolized patients underwent contrast-enhanced CT scans within 30 days after EVAR (mean 6 days; range 1–26 days). We identified no IMA-related early type II endoleaks. There were one type I endoleak (1/31; 3.2 %), one type III endoleak (1/31; 3.2 %), and six (6/31; 19.4 %) early type II endoleaks. All type II endoleaks were small and attributed to a retrograde flow from lumbar arteries, mostly fourth lumbar arteries (5/6; 83.3 %). Three patients with early lumbar type II endoleak had follow-up for more than 6 months available (range 7–10 months). Aneurysm sac size was stable in two and decreased in one patient.
Fig. 5 Length of the IMA in 31 patients
In the control group, we observed four type I endoleaks (4/43; 9.3 %) and 14 early type II endoleaks (14/43; 32.6 %). Most of these type II endoleaks were complex IMA-lumbar type II endoleaks (11/14; 78.6 %); three (3/14; 21.4 %) patients had lumbar type II endoleaks. Twelve patients with early-type II endoleaks (12/14; 85.7 %) had follow-up data for more than 6 months available [mean 26 (range 9–47) months]. Eight patients—all with a complex IMA-lumbar type II endoleak—showed a significant aneurysm sac enlargement (C5 % volume increase) during follow-up. In comparison, preoperative IMA embolization significantly reduced the incidence of early complex IMAlumbar type II endoleaks after EVAR (0/31 vs. 11/43; p = 0.002). The incidence of lumbar type II endoleaks was comparable in both groups (6/31 vs. 3/43; p = 0.15).
Discussion The low-profile design of the AVP-4 eliminates the need for large-lumen guiding catheters or sheaths compared with its larger precursor AVP-II, enabling the deployment of the plug in smaller arteries. Since its introduction, several reports and case series described the use of the AVP-4 for the embolization of arteriovenous fistulas [15], treatment of pseudoaneurysms and hemorrhages [16–19], occlusions of aneurysms [17, 19, 20], and for preparation before selective internal radiotherapy [19, 21]. Up to now, IMA embolization before EVAR using the AVP-4 has been reported only by Mordasini (two patients) [17] and Pech (three patients) [19].
123
R. Mu¨ller-Wille et al.: IMA Embolization Using AVP-4
The optimal device for preoperative IMA embolizations should safely occlude the vessel and should be short enough to allow collateral perfusion of the IMA branches. Our data supported the impression that the AVP-4 is an effective and safe device for IMA embolizations before EVAR. Occlusion of the IMA was achieved on average 5 min after placement of a single AVP-4. In two patients, occlusion time was longer than 10 min, thus additional Gelfoam embolization was performed. It is possible that occlusion would have occurred without Gelfoam as well. Plug oversizing between 50 and 100 % provided a secure fixation of the plug in all cases. Unlike the description by Pech et al. [19], we had no problems in disconnecting the plug. The released AVP-4 was short enough to ensure an adequate distance between the plug and the first branches of the IMA. In most cases, the 6-mm AVP-4 was used, which had a mean length of 16 mm after detachment. In the present study, the measured length of IMA matched with the reported range of 2–7 (mean 3.5) cm based on dissections of adult cadavers [23]. Furthermore, the possibility of angiography before final plug detachment through the delivery catheter provides additional security. If the position of the AVP-4 is suboptimal, the device can be retracted and repositioned. In most cases, we used a transbrachial access for IMA embolization, because the IMA runs in most cases steeply downwards and a straight catheter position was preferable for a safe and stable positioning of the relatively stiff device. In our series, embolization via the femoral approach was technically possible but more difficult, and in two cases, the plug protruded slightly into the aortic lumen. Mordasini et al. [17] describe an unsuccessful IMA embolization with an AVP-4 via a femoral approach as a result of repeated catheter tip dislocation. Similarly Muthu et al. [11] reported that transfemoral coil embolization of the IMA failed because of unstable catheter position. All previous studies used coils for IMA embolization before EVAR [9, 10, 12–14]. Up to now, no studies have compared the AVP-4 with coils in this setting regarding technical success, procedural time, radiation dose, and costs. Nevertheless, it has been shown that the precursor AVP-II had advantages over coils for selective embolization of larger arteries. In a randomized trial, the embolization of the gastroduodenal artery before internal radiotherapy using the AVP-II was associated with a shorter duration of the procedure, shorter embolization times, and less exposure to radiation [24]. Furthermore, the material cost for embolization was approximately 30 % lower with the AVP-II than with coil embolization [24]. It has recently been published that the risk of bowel ischemia after coil embolizations of the IMA is \1 % [14]. Nevertheless, we deem it absolutely necessary to perform a selective angiogram of the SMA to evaluate the collateral blood flow through Riolan’s arcade before occluding the IMA trunk regardless with which material.
123
We observed a relatively high incidence of lumbar type II endoleaks in our embolized patient group. However, the incidence of lumbar type II endoleaks was statistically not different to our control group. It shall be taken into account that preoperative IMA embolization significantly reduced the incidence of complex IMA-lumbar type II endoleaks, which had more clinical significance than small lumbar endoleaks, hence most control patients with complex IMAlumbar endoleaks showed aneurysm sac enlargement during follow-up. One major drawback of our study is that not all patients have follow-up data (more than 6 months) available to date due to the recent data set. Thus, incidence of late onset IMA-related type II endoleaks and aneurysm size changes were not evaluable. Furthermore, randomized studies are warranted to compare the AVP-4 with coils in this setting.
Conclusions The AVP-4 is a safe and effective embolization device for selective IMA embolization before EVAR. Conflict of interest of interest.
The authors declare that they have no conflict
References 1. Veith FJ, Baum RA, Ohki T et al (2002) Nature and significance of endoleaks and endotension: summary of opinions expressed at an international conference. J Vasc Surg 35:1029–1035 2. Velazquez OC, Baum RA, Carpenter JP et al (2000) Relationship between preoperative patency of the inferior mesenteric artery and subsequent occurrence of type II endoleak in patients undergoing endovascular repair of abdominal aortic aneurysms. J Vasc Surg 32(4):777–788 3. Jones JE, Atkins MD, Brewster DC et al (2007) Persistent type 2 endoleak after endovascular repair of abdominal aortic aneurysm is associated with adverse late outcomes. J Vasc Surg 46(1):1–8 4. Sampaio SM, Panneton JM, Mozes GI et al (2005) Aneurysm sac thrombus load predicts type II endoleaks after endovascular aneurysm repair. Ann Vasc Surg 19(3):302–309 5. Fan CM, Rafferty EA, Geller SC et al (2001) Endovascular stentgraft in abdominal aortic aneurysms: the relationship between patent vessels that arise from the aneurysmal sac and early endoleak. Radiology 218(1):176–182 6. Abularrage CJ, Crawford RS, Conrad MF et al (2010) Preoperative variables predict persistent type 2 endoleak after endovascular aneurysm repair. J Vasc Surg 52(1):19–24 7. AbuRahma AF, Mousa AY, Campbell JE et al (2011) The relationship of preoperative thrombus load and location to the development of type II endoleak and sac regression. J Vasc Surg 53(6):1534–1541 8. Brountzos E, Karagiannis G, Panagiotou I et al (2012) Risk factors for the development of persistent type II endoleaks after endovascular repair of infrarenal abdominal aortic aneurysms. Diagn Interv Radiol 18(3):307–313
R. Mu¨ller-Wille et al.: IMA Embolization Using AVP-4 9. Axelrod DJ, Lookstein RA, Guller J et al (2004) Inferior mesenteric artery embolization before endovascular aneurysm repair: technique and initial results. J Vasc Interv Radiol 15(11):1263–1267 10. Bonvini R, Alerci M, Antonucci F et al (2003) Preoperative embolization of collateral side branches: a valid means to reduce type II endoleaks after endovascular AAA repair. J Endovasc Ther 10(2):227–232 11. Muthu C, Maani J, Plank LD et al (2007) Strategies to reduce the rate of type II endoleaks: routine intraoperative embolization of the inferior mesenteric artery and thrombin injection into the aneurysm sac. J Endovasc Ther 14(5):661–668 12. Nevala T, Biancari F, Manninen H et al (2010) Inferior mesenteric artery embolization before endovascular repair of an abdominal aortic aneurysm: effect on type II endoleak and aneurysm shrinkage. J Vasc Interv Radiol 21(2):181–185 13. Parry DJ, Kessel DO, Robertson I et al (2002) Type II endoleaks: predictable, preventable, and sometimes treatable? J Vasc Surg 36(1):105–110 14. Ward TJ, Cohen S, Fischman AM et al (2013) Preoperative inferior mesenteric artery embolization before endovascular aneurysm repair: decreased incidence of type II endoleak and aneurysm sac enlargement with 24-month follow-up. J Vasc Interv Radiol 24(1):49–55 15. Buttarelli L, Capocasale E, Marcato C et al (2011) Embolization of pancreatic allograft arteriovenous fistula with the Amplatzer Vascular Plug 4: case report and literature analysis. Transplant Proc 43(10):4044–4047 16. Ferro C, Rossi UG, Bovio G et al (2010) The Amplatzer Vascular Plug 4: preliminary experience. Cardiovasc Interv Radiol 33(4):844–848
17. Mordasini P, Szucs-Farkas Z, Do DD et al (2010) Use of a latestgeneration vascular plug for peripheral vascular embolization with use of a diagnostic catheter: preliminary clinical experience. J Vasc Interv Radiol 21(8):1185–1190 18. Ng EH, Comin J, David E et al (2012) Amplatzer vascular plug 4 for proximal splenic artery embolization in blunt trauma. J Vasc Interv Radiol 23(7):976–979 19. Pech M, Mohnike K, Wieners G et al (2011) Advantages and disadvantages of the Amplatzer Vascular Plug IV in visceral embolization: report of 50 placements. Cardiovasc Interv Radiol 34(5):1069–1073 20. Rossi UG, Seitun S, Ferro C (2013) Endovascular embolization of a third jejunal artery aneurysm: isolation technique using the Amplatzer Vascular Plug 4. Catheter Cardiovasc Interv 81(6): 1049–1052 21. Yildiz AE, Peynircioglu B, Cil BE (2012) Applications of the Amplatzer Vascular Plug 4. Diagn Interv Radiol 18(2):225–230 22. Sacks D, McClenny TE, Cardella JF et al (2003) Society of interventional radiology clinical practice guidelines. J Vasc Interv Radiol 14(9 Pt 2):S199–S202 23. Michels NA, Siddharth P, Kornblith PL et al (1965) The variant blood supply to the descending colon, rectosigmoid and rectum based on 400 dissections. Its importance in regional resections—a review of medical literature. Dis Colon Rectum 8:251–278 24. Pech M, Kraetsch A, Wieners G et al (2009) Embolization of the gastroduodenal artery before selective internal radiotherapy: a prospectively randomized trial comparing platinum-fibered microcoils with the Amplatzer Vascular Plug II. Cardiovasc Interv Radiol 32(3):455–461
123
