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First report of a late type III endoleak from fabric tears of a Zenith stent graft

2008; Elsevier BV; Volume: 48; Issue: 3 Linguagem: Inglês

10.1016/j.jvs.2008.03.047

1097-6809

Anders Wanhainen, Rickard Nyman, Mats-Ola Eriksson, Martin Björck,

Vascular Procedures and Complications

We report a case of a late type III endoleak from a hole in the fabric of the main body of a Zenith bifurcated endograft 7 years after implantation. Abdominal pain and a rapidly expanding aneurysm were eventually followed by rupture. The defect was detected at open surgery, whereas no evidence of endoleak was found at preoperative computed tomography (CT) or angiogram. The defect was repaired by a relining procedure with an Excluder stent graft. The patient, however, died 3 weeks after admission. We report a case of a late type III endoleak from a hole in the fabric of the main body of a Zenith bifurcated endograft 7 years after implantation. Abdominal pain and a rapidly expanding aneurysm were eventually followed by rupture. The defect was detected at open surgery, whereas no evidence of endoleak was found at preoperative computed tomography (CT) or angiogram. The defect was repaired by a relining procedure with an Excluder stent graft. The patient, however, died 3 weeks after admission. Among recent advancements in the management of abdominal aortic aneurysm (AAA), the introduction of endovascular aneurysm repair (EVAR) is the most important. Since its introduction in 1986,1Volodos N.L. Shekhanin V.E. Karpovich I.P. Troian V.I. Gur'ev IuA. [A self-fixing synthetic blood vessel endoprosthesis.].Vestn Khir Im I I Grek. 1986; 137: 123-125PubMed Google Scholar, 2Volodos N.L. Karpovich I.P. Troyan V.I. Kalashnikova YuV. Shekhanin V.E. Ternyuk N.E. et al.Clinical experience of the use of self-fixing synthetic prostheses for remote endoprosthetics of the thoracic and the abdominal aorta and iliac arteries through the femoral artery and as intraoperative endoprosthesis for aorta reconstruction.Vasa Suppl. 1991; 33: 93-95PubMed Google Scholar, 3Parodi J. Palmaz J. Barone H. Transfemoral intraluminal graft implantation for abdominal aortic aneurysms.Ann Vasc Surg. 1991; 5: 491-499Abstract Full Text PDF PubMed Scopus (2972) Google Scholar EVAR has become increasingly popular. This technique offers a short-term benefit over open repair4Greenhalgh R.M. Brown L.C. Kwong G.P. Powell J.T. Thompson S.G. EVAR trial participantsComparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomised controlled trial.Lancet. 2004; 364: 843-848Abstract Full Text Full Text PDF PubMed Scopus (1634) Google Scholar; however, there is still uncertainty about the long-term durability of EVAR. Late complications after EVAR include endoleaks, which ultimately may cause aneurysm rupture and death. Type III endoleak arises from a defect in the graft fabric, inadequate seal, or disconnection of modular graft components5White G.H. May J. Waugh R.C. Chaufour X. Yu W. Type II and type IV endoleak: toward a complete definition of blood flow in the sac after endoluminal AAA repair.J Endovasc Surg. 1998; 4: 305-309Crossref Scopus (355) Google Scholar and is associated with high risk of aneurysm rupture.6Harris P.L. Vallabhaneni R. Desgranges P. Becquemin J.P. van Marrewijk C. Laheij R.J.F. Incidence and risk factors of late rupture, conversion and death after endovascular repair of infrarenal aortic aneurysms: the EUROSTAR experience.J Vasc Surg. 2000; 32: 739-749Abstract Full Text Full Text PDF PubMed Scopus (662) Google Scholar We report a case of a fatal late type III endoleak from a large hole in the fabric of the main body of the Zenith bifurcated endograft 7 years after implantation. A 77-year-old man with a history of a myocardial infarction and coronary bypass surgery underwent endovascular exclusion of an expanding 70-mm AAA in the year 2000. The proximal neck was 21 mm in diameter and 30 mm in length with no angulation. A Zenith bifurcated endograft (Cook Inc, Bloomington, Ind) was implanted uneventfully. Completion angiogram showed no endoleak. Follow-up with duplex scan and computed tomography (CT) showed, until March 2007, a stable sac that had decreased to 52 mm, without any detected endoleak. In May 2007, 7 years after implantation and 2 months after the last duplex scan, the patient presented with abdominal pain. At the time of presentation, he was 84 years old and had developed Alzheimer disease, although after medication he still managed to live in his own apartment. An urgent contrast CT revealed an intact 65-mm aneurysm but no endoleak, extravasations, or migration of the stent graft. Neither the general surgeon attending the patient nor the radiologist has commented on the fact that the AAA had expanded 10 mm compared with the duplex scan and CT taken 2 months earlier (Fig 1 a). The pain diminished and the patient was sent home the next day; however, 48 hours after the initial symptoms, he returned with renewed abdominal pain and a tender aneurysm. A CT showed that the aneurysm had expanded to 75 mm. An emergency angiography was performed (Fig 2). No endoleak was detected and the sac pressure, measured through a direct aneurysm sac puncture, was 38 mm Hg without pulsatility. This finding, together with high blood pressure (220 mm Hg), made us suspect an intermittent type II endoleak. Two lumbar arteries at the level of the aneurysm sac were therefore embolized with coils after catheterization through the hypogastric arteries, and antihypertensive treatment was initiated.Fig 2Lateral (a) and frontal (b) preoperative angiograms.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Over the next 48 hours, the hemoglobin level decreased from 140 to 77 g/L, and a CT revealed a large retroperitoneal hematoma as well as intraperitoneal bleeding (Fig 1 b). The patient was taken to our hybrid operating theater. No endoleak was found at angiogram, and an occluding balloon was placed in the proximal stent graft. A laparotomy confirmed the CT finding of a large retroperitoneal hematoma and massive intra-abdominal bleeding. With an aortic occluding balloon used for proximal control, the aneurysm sac was opened and multiple minor bleedings from holes in the fabric of the main body of the bifurcated Zenith endograft were found in close conjunction with stent sutures (Fig 3 a). One of the bleedings, however, was more prominent and was situated close to a stent suture break. The stent graft was firmly fixated proximally and no type I or type II endoleak was observed. Because of the patient's general health status, with advanced age and Alzheimer disease, we refrained from a graft replacement, which would have included a demanding suprarenal aortic clamping. The defects were instead repaired by a relining procedure with an Excluder bifurcated stent graft (W.L. Gore and Associates, Flagstaff, Ariz) delivered percutaneously. The total volume of blood loss was estimated as 5.5 L. No heparin was given intra- or postoperatively. After the immediate postoperative period, the patient had low-grade bleeding with a transfusion need of only two units of blood over a 2-week period. He developed episodes of hypotension and mental confusion. Again because of his advanced age and Alzheimer disease, the treatment was limited according to the wish of the family. Three weeks after admission, the patient died of heart failure that developed gradually. Autopsy showed a large rupture in the region of the left posterior aortic wall, which was not associated with the puncture site. Despite a partial detachment of the suprarenal stent, a firm fixation of the stent graft was noted (Fig 4 a). A fracture on the main body was noted in the long stent proximal to the bifurcation (Fig 4 b). Minor holes in the fabric were observed in conjunction with several stent sutures (Fig 3 b). Perioperative observation of larger-volume bleeding through the stent graft was explained by a fairly large hole in the fabric in conjunction with a stent suture break (Fig 5).Fig 5a, A large hole (arrow) in the fabric in conjunction with a stent suture break. b, Close up of the fabric tear (postmortem examination).View Large Image Figure ViewerDownload Hi-res image Download (PPT) The Zenith bifurcated stent graft system is one of several commercially available devices. It is a tri-modular system constructed of self-expanding stainless steel Z-shaped stents attached with surgical sutures to a woven polyester graft material. It also has an uncovered stent with barbs that extend into the suprarenal aorta for proximal fixation. Since its introduction in 1997, the current generation of the Zenith AAA Endovascular Graft has undergone two minor modifications: an increase in the number of barbs on the uncovered proximal stent in 1997, and additional sutures to improve the fixation of the most proximal suprarenal stent in 2002. The device used in the present case report was made in the year 2000, and thus prior to the 2002 modification but after the 1997 modification. So far more than 75,000 Zenith devices have been implanted worldwide (Cook Europe, Bjaeverskov, Denmark, personal communication, January 14, 2008). Late failures of Zenith stent graft structure are rare. Breakage of the sutures that attach the proximal stent was observed in previous models of the Zenith stent graft, prior to 2002. In response to these reports, the manufacturer doubled the number of sutures holding the proximal stent in place, which greatly reduced the risk for proximal stent separation. Stent fractures, predominantly located in the long stent proximal to the bifurcation, are a common finding; however, they are hardly ever clinically relevant.7Hiramoto J.S. Reilly L.M. Schneider D.B. Sivamurthy N. Rapp J.H. Chuter T.A.M. Long-term outcome and reintervention after endovascular abdominal aortic aneurysm repair using the Zenith stent graft.J Vasc Surg. 2007; 45: 461-466Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar Type III endoleak due to fabric defect is a rare but serious complication. It has been reported with other stent graft systems 8Teutelink A. van der Laan M.J. Milner R. Blankensteijn J.D. Fabric tears as a new cause of type III endoleak with Ancure endograft.J Vasc Surg. 2003; 38: 843-846Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar, 9Biebl M. Hakaim A.G. Oldenburg W.A. Klocker J. McKinney J.M. Paz-Fumagalli R. Management of a large intraoperative type IIIb endoleak in a bifurcated endograft—a case report.Vasc Endovascular Surg. 2005; 39: 267-271Crossref PubMed Scopus (14) Google Scholar, 10Lee W.A. Huber T.S. Seeger J.M. Late type III endoleak from graft erosion of an Excluder stent graft: a case report.J Vasc Surg. 2006; 44: 183-185Abstract Full Text Full Text PDF PubMed Scopus (30) Google Scholar and with the Zenith system in one case report in which the fabric tear was caused by balloon modeling during the implantation procedure.11van der Vliet J.A. Blankensteijn J.D. Kool L.J. Type III endoleak caused by fabric tear of a Zenith endograft after low-pressure balloon modeling.J Vasc Interv Radiol. 2005; 16: 1042-1044Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar No instance of late fabric disruption in a Zenith stent graft has previously been reported. Minor holes in conjunction with stent sutures are, according to the stent manufacturer, normal and should not be of any clinical importance (Cook Europe, Bjaeverskov, Denmark, personal communication, January 14, 2008). However, the observed large hole in the fabric represents a major failure of the device. A possible mechanism may be a primary stent suture break, which causes the movable stent to wear a hole in the fabric. The present case report clearly illustrates the diagnostic challenges associated with late endoleak due to fabric defect. The sudden onset makes it difficult to prevent by means of surveillance, and the specific nature of a late type III endoleak caused by a fabric defect makes it difficult to visualize with CT and angiogram. The inability of CT and angiogram to detect the endoleak is difficult to explain, and we can only speculate on the cause. One possible mechanism may be that the pressure in the intact sac prevents sufficient extravasations of contrast to be detected. Furthermore, an endoleak may pressurize the AAA sac nonuniformly, with higher pressure in the endoleak nidus than in the thrombus,12Dias N.V. Ivancev K. Resch T.A. Malina M. Sonesson B. Endoleaks after endovascular aneurysm repair lead to nonuniform intra-aneurysm sac pressure.J Vasc Surg. 2007; 2: 197-203Abstract Full Text Full Text PDF Scopus (48) Google Scholar which probably explained the inability to detect a high pressure inside the aneurysm at the time of puncture. Continued bleeding after relining may be explained by back bleeding from lumbar arteries, which was previously silent because of the pressure inside an intact aneurysm sac. This is the first reported case of a late type III endoleak from fabric tears of a Zenith stent graft. It is a serious and potentially lethal complication as well as a diagnostic challenge. With the limited long-term follow-up data in the literature, the current finding is disturbing.