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Conservative management of persistent aortocaval fistula after endovascular aortic repair

2013; Elsevier BV; Volume: 58; Issue: 4 Linguagem: Inglês

10.1016/j.jvs.2012.10.138

1097-6809

Koen M. van de Luijtgaarden, Frederico Bastos Gonçalves, Ellen V. Rouwet, Johanna M. Hendriks, Sander Ten Raa, Hence J.M. Verhagen,

Aortic Disease and Treatment Approaches

Endovascular repair is a valid alternative for patients with abdominal aortic aneurysms. However, in patients with concomitant aortocaval fistulas, type II endoleaks may result in a persistent communication between the aneurysm sac and the inferior vena cava. In these patients, prompt closure of the persistent fistula has been advocated. We present a patient with an abdominal aortic aneurysm, with aortocaval fistula, who was managed endovascularly. Aneurysm sac shrinkage was observed despite persistent aortocaval communication due to type II endoleak. This case demonstrates that conservative management of type II endoleaks associated with persistent aortocaval fistulas is possible and may result in favorable aneurysm sac remodelling. Endovascular repair is a valid alternative for patients with abdominal aortic aneurysms. However, in patients with concomitant aortocaval fistulas, type II endoleaks may result in a persistent communication between the aneurysm sac and the inferior vena cava. In these patients, prompt closure of the persistent fistula has been advocated. We present a patient with an abdominal aortic aneurysm, with aortocaval fistula, who was managed endovascularly. Aneurysm sac shrinkage was observed despite persistent aortocaval communication due to type II endoleak. This case demonstrates that conservative management of type II endoleaks associated with persistent aortocaval fistulas is possible and may result in favorable aneurysm sac remodelling. Endovascular aneurysm repair (EVAR) is a valid alternative over open reconstruction in patients with (ruptured) abdominal aortic aneurysms (AAAs).1Moll F.L. Powell J.T. Fraedrich G. Verzini F. Haulon S. Waltham M. et al.Management of abdominal aortic aneurysms clinical practice guidelines of the European Society for Vascular Surgery.Eur J Vasc Endovasc Surg. 2011; 41: S1-58Abstract Full Text Full Text PDF PubMed Scopus (1016) Google Scholar However, in patients with concomitant arteriovenous (AV) fistulas, type II endoleaks may result in a persistent communication between the aneurysm sac and the venous system. In the current literature, early closure of the fistula has been advocated due to concerns about future aneurysm-related complications.2Burke C. Mauro M.A. SIR 2003 film panel case 8: aortocaval fistula supplied by a type II endoleak.J Vasc Interv Radiol. 2003; 14: 813-817Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar, 3Kopp R. Weidenhagen R. Hoffmann R. Waggershauser T. Meimarakis G. Andrassy J. et al.Immediate endovascular treatment of an aortoiliac aneurysm ruptured into the inferior vena cava.Ann Vasc Surg. 2006; 20: 525-528Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar We present an AAA patient with an aortocaval fistula who was managed conservatively and in whom favorable aneurysm sac remodelling was observed, despite a persistent aortocaval communication due to a large type II endoleak. A 61-year-old man presented at the emergency department with acute low back and abdominal pain. The patient had a history of hypertension and chronic obstructive pulmonary disease. Prescription medications included a β-blocker, an angiotensin II inhibitor, and a short-acting β2-adrenergic receptor agonist. On admission, his heart rate and blood pressure were within normal reference ranges (72 beats/min and 123/87 mm Hg, respectively). Physical examination revealed a tender, pulsatile abdominal mass, without abdominal bruit or thrill. No clinical signs of venous hypertension or heart failure were observed. Laboratory results showed no hepatic or kidney dysfunction. A computed tomography angiography (CTA) demonstrated a large AAA (10 cm in transverse diameter) with an associated aortocaval fistula (Fig 1). The patient's anatomy was suitable for EVAR, and a bifurcated Endurant endovascular device (Medtronic Inc, Minneapolis, Minn) was used for exclusion. The perioperative final angiography showed an evident type II endoleak from the inferior mesenteric artery, but no further action was taken. The patient had an uneventful postoperative recovery and was discharged after 5 days. In addition, postoperative renal and hepatic function remained normal. A postoperative CTA showed persistent communication with the inferior vena cava (IVC) as a result of the type II endoleak (Fig 1). To evaluate the systemic repercussion of the persistent aortocaval fistula, the patient was referred for a formal cardiac evaluation after 3 months. He was asymptomatic, and results of electrocardiography were normal. Echocardiography showed a normal systolic left ventricular ejection fraction, with no signs of increased right atrial filling pressure and a physiologic collapse of the IVC. Consequently, no further action was taken. After 1 year of follow-up, CTA showed shrinkage of the aneurysm sac diameter by 10 mm and an 8% reduction in volume compared with the postoperative CTA,4van Prehn J. van der Wal M.B. Vincken K. Bartels L.W. Moll F.L. van Herwaarden J.A. Intra- and interobserver variability of aortic aneurysm volume measurement with fast CTA postprocessing software.J Endovasc Ther. 2008; 15: 504-510Crossref PubMed Scopus (55) Google Scholar despite the persistent type II endoleak (Fig 2). Persistent AV fistulas after EVAR have been reported, but the natural history of this complication remains unknown; moreover, there is no clear evidence in the current literature supporting treatment over observation. Our case demonstrates that persistent aortocaval communication due to type II endoleak is possible and that a conservative approach may be preferable in the absence of systemic manifestations and in the face of favorable aneurysm sac remodelling. Aortocaval fistulas are, by definition, high-flow fistulas that may result in complications due to increased cardiac output and venous hypertension.5Davidovic L. Dragas M. Cvetkovic S. Kostic D. Cinara I. Banzic I. Twenty years of experience in the treatment of spontaneous aorto-venous fistulas in a developing country.World J Surg. 2011; 35: 1829-1834Crossref PubMed Scopus (19) Google Scholar, 6Nennhaus H.P. Javid H. The distinct syndrome of spontaneous abdominal aortocaval fistula.Am J Med. 1968; 44: 464-473Abstract Full Text PDF PubMed Scopus (76) Google Scholar, 7Sobrinho G. Ferreira M.E. Albino J.P. Gomes H. Capitao L.M. Acute ischemic hepatitis in aortocaval fistula.Eur J Vasc Endovasc Surg. 2005; 29: 239-243Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar Treatment is therefore advised. Patients with aortocaval fistulas have traditionally been treated with open repair, with mortality rates ranging from 16% to 66%.5Davidovic L. Dragas M. Cvetkovic S. Kostic D. Cinara I. Banzic I. Twenty years of experience in the treatment of spontaneous aorto-venous fistulas in a developing country.World J Surg. 2011; 35: 1829-1834Crossref PubMed Scopus (19) Google Scholar Because EVAR has been adopted as valid treatment for (ruptured) AAAs,1Moll F.L. Powell J.T. Fraedrich G. Verzini F. Haulon S. Waltham M. et al.Management of abdominal aortic aneurysms clinical practice guidelines of the European Society for Vascular Surgery.Eur J Vasc Endovasc Surg. 2011; 41: S1-58Abstract Full Text Full Text PDF PubMed Scopus (1016) Google Scholar also in the presence of aortocaval fistulas, persistent communication between the aneurysm sac and the IVC may occur due to a type II endoleak. The question remains if—and how—we should manage these persistent fistulas. Type II endoleak is defined as persistent retrograde flow into the aneurysm sac from the inferior mesenteric, lumbar, or other arteries, without attachment-site leak.8White G.H. May J. Waugh R.C. Chaufour X. Yu W. Type III and type IV endoleak: toward a complete definition of blood flow in the sac after endoluminal AAA repair.J Endovasc Surg. 1998; 5: 305-309Crossref PubMed Scopus (344) Google Scholar They are classified as (a) simple, with one patent branch or (b) complex, with two or more patent branches.9Veith F.J. Johnston K.W. Endovascular treatment of abdominal aortic aneurysms: an innovation in evolution and under evaluation.J Vasc Surg. 2002; 35: 183Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar These endoleaks are considered important because they may result in repressurization of the excluded aneurysm sac, with consequent growth and, ultimately, rupture. However, in the presence of persistent caval communication, type II endoleaks are subject to different flow and pressure dynamics caused by the connection with the low-pressure venous system (2-8 mm Hg).10Melby S.J. Moazami N. Damiana R. Cardiac surgery.in: Klingensmith M.E. The Washington manual of surgery. Chapter 30. Lippincott Williams & Wilkins, Philadelphia, PA2008: 509-528Google Scholar The connection causes a pressure gradient, resulting in a decrease of in-sac pressure (Fig 3), mimicking the concept of aneurysm sac fenestration.11Voute M.T. Bastos Goncalves F.M. Hendriks J.M. Metz R. van Sambeek M.R. Muhs B.E. et al.Treatment of post-implantation aneurysm growth by laparoscopic sac fenestration: long-term results.Eur J Vasc Endovasc Surg. 2012; 44: 40-44Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar Owing to the low-pressure nature, this special type of type II endoleak has a very low probability of aneurysm sac growth. This was confirmed in our patient, in whom we observed significant aneurysm sac shrinkage at 1 year (Fig 2). Several cases of endovascular treatment for AAA patients with aortocaval fistulas have been described.12Beveridge C.J. Pleass H.C. Chamberlain J. Wyatt M.G. Rose J.D. Aortoiliac aneurysm with arteriocaval fistula treated by a bifurcated endovascular stent-graft.Cardiovasc Intervent Radiol. 1998; 21: 244-246Crossref PubMed Scopus (43) Google Scholar, 13Umscheid T. Stelter W.J. Endovascular treatment of an aortic aneurysm ruptured into the inferior vena cava.J Endovasc Ther. 2000; 7: 31-35Crossref PubMed Google Scholar, 14Lau L.L. O'Reilly M.J. Johnston L.C. Lee B. Endovascular stent-graft repair of primary aortocaval fistula with an abdominal aortoiliac aneurysm.J Vasc Surg. 2001; 33: 425-428Abstract Full Text Full Text PDF PubMed Scopus (62) Google Scholar, 15Vetrhus M. McWilliams R. Tan C.K. Brennan J. Gilling-Smith G. Harris P.L. Endovascular repair of abdominal aortic aneurysms with aortocaval fistula.Eur J Vasc Endovasc Surg. 2005; 30: 640-643Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar However, only four case reports of persistent aortocaval fistulas have been published to date. Burke et al2Burke C. Mauro M.A. SIR 2003 film panel case 8: aortocaval fistula supplied by a type II endoleak.J Vasc Interv Radiol. 2003; 14: 813-817Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar reported a patient with a type II endoleak 4 days postoperatively, which was immediately treated with a cuff in the IVC and glue in the aneurysm sac. Kopp et al3Kopp R. Weidenhagen R. Hoffmann R. Waggershauser T. Meimarakis G. Andrassy J. et al.Immediate endovascular treatment of an aortoiliac aneurysm ruptured into the inferior vena cava.Ann Vasc Surg. 2006; 20: 525-528Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar reported a similar patient who underwent secondary coiling of a persistent type II endoleak. Lastly, Vetrhus et al15Vetrhus M. McWilliams R. Tan C.K. Brennan J. Gilling-Smith G. Harris P.L. Endovascular repair of abdominal aortic aneurysms with aortocaval fistula.Eur J Vasc Endovasc Surg. 2005; 30: 640-643Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar suggested that persistent fistulas in this context tend to resolve spontaneously, which did not occur in our patient. The fistulas in their two patients resolved on-table in one patient and after 4 weeks in the other, without further intervention.15Vetrhus M. McWilliams R. Tan C.K. Brennan J. Gilling-Smith G. Harris P.L. Endovascular repair of abdominal aortic aneurysms with aortocaval fistula.Eur J Vasc Endovasc Surg. 2005; 30: 640-643Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar Taken together, the chance of a persistent aortocaval fistula after EVAR is rather small but is considerable due to the high frequency of type II endoleaks after EVAR. We treated our patient conservatively because no systemic repercussions of the AV fistula were present and secondary interventions for type II endoleaks are generally reserved for persistent endoleaks (≥6 months) associated with aneurysm sac enlargement.16Abularrage C.J. Crawford R.S. Conrad M.F. Lee H. Kwolek C.J. Brewster D.C. et al.Preoperative variables predict persistent type 2 endoleak after endovascular aneurysm repair.J Vasc Surg. 2010; 52: 19-24Abstract Full Text Full Text PDF PubMed Scopus (87) Google Scholar However, we acknowledge that conservative management in our patient might result in complications. Increased cardiac output and, ultimately, heart failure may develop from AV fistulas. Nevertheless, we considered this risk was relatively small because the arterial component of the fistula in our patient resulted from retrograde flow from the inferior mesenteric artery. Moreover, a physiologic collapse of the IVC was observed, emphasizing the low-pressure nature of the fistula. Nonetheless, careful and continued cardiac evaluation is required to ensure early identification of this possible complication. In addition, embolization may occur as a result of dislodgment of aneurysm sac debris; however, we believe that the risk for clinically significant embolization is minute. First, the chance of embolization from untreated AAAs is very small.17Baxter B.T. McGee G.S. Flinn W.R. McCarthy W.J. Pearce W.H. Yao J.S. Distal embolization as a presenting symptom of aortic aneurysms.Am J Surg. 1990; 160: 197-201Abstract Full Text PDF PubMed Scopus (36) Google Scholar Second, closing an AV fistula with an implant may also induce thromboembolism. Lastly, the chance of embolization due to manipulation during secondary intervention to close the AV fistula is probably higher than the embolization risk itself. Because compression of the IVC was observed, thrombosis could occur. Therefore, implantation of an endograft in the IVC could be considered to exclude the AV fistula and treat IVC compression. However, this compression is frequently observed in EVAR patients, and caval thrombosis is anecdotic. Also, stent graft placement in a significantly compressed IVC may yield a suboptimal result, with a risk of endograft collapse or acute stent thrombosis, or both. Our case shows that in the absence of systemic repercussions, persistent aortocaval fistulas due to type II endoleak after EVAR may be managed conservatively and that favorable remodeling of the aneurysm sac is possible. Nevertheless, close observation, including periodic cardiac evaluation, is mandatory. Secondary intervention may be reserved for patients with persistent aortocaval fistulas combined with aneurysm sac enlargement or systemic manifestations.