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When stent-grafts fail: extraction and open surgical repair of the thoracic aorta.

Year: 2011
Type: article
Abstract: The use of stent-grafts to perform abdominal endovascular aortic repair (EVAR) and thoracic endovascular aortic repair (TEVAR) in patients with aortic aneurysms was widely adopted upon their approval in 1999 and 2005, respectively, by the U.S. Food and Drug Administration. Since that time, usage rates have stabilized: currently, EVAR is used in as many as 70% of all abdominal aortic repairs,1 whereas TEVAR accounts for roughly 25% of all descending thoracic aortic repairs in patients less than 65 years of age2,3 and for about 45% in patients more than 65 years of age.4 As the number of EVAR and TEVAR survivors has grown, reports of complications have similarly increased. Although secondary endovascular rescue measures are often undertaken, patients with serious complications (for example, continued aneurysmal expansion, continued dilation of nearby aortic sections, infection, or device migration) often are converted, ultimately, to open aortic repair; the stent-graft is partly or fully extracted (often via a thoracoabdominal approach in patients with previous EVAR repairs), and the diseased aorta is replaced with a polyester graft.5–11 Patients who need stent-graft excision often present with complicating factors beyond a failed EVAR or TEVAR, such as chronic aortic dissection, a genetically triggered aortic disease, or a history of both endovascular and open aortic repairs. Nevertheless, in many ways, our repairs that involve stent-graft explantation are similar to our traditional open descending thoracic and thoracoabdominal repairs, in that the extent of repair generally dictates which components of our multimodal approach to repair are used (Fig. 1).11,12 For example, we use our standard extended thoracotomy for repairs limited to the descending thoracic aorta, and we use our utility thoracoabdominal incision for repairs involving the abdominal aorta. In patients who need open repair for failed EVAR, we have found that using an oblique thoracoabdominal incision at the 9th or 10th intercostal space (in the manner of a Crawford extent IV thoracoabdominal aortic aneurysm repair) provides the exposure necessary to appropriately manage the visceral branches. We also apply our standard approach to organ and spinal cord protection during stent-graft extraction procedures.11,12 Fig. 1 Late conversion to open repair in a 54-year-old man who A) had undergone endovascular repair of a limited section of the descending thoracic aorta, subsequent to acute type III aortic dissection. Despite this repair, he had become symptomatic 4 ... We use left-heart bypass to provide distal aortic perfusion during extent I and II thoracoabdominal repairs, and we use cold crystalloid renal perfusion whenever the renal artery ostia are accessible. We tend to reserve cerebrospinal fluid drainage for patients undergoing thoracoabdominal extent I and II repairs, but we use this adjunct selectively in other patients, too—particularly those with risk factors such as prior abdominal aortic repair or contained rupture. We also aggressively reattach selected patent segmental arteries between T8 and L2. Whereas direct reattachment of segmental arteries may be possible in aortic sections previously covered by a stent-graft, sometimes a small-diameter graft (for example, an 8-mm graft) may be needed to create a conduit to selected spinal arteries. In addition, the approach to reattachment may combine both of the above-mentioned strategies in a single patient, and there may be gaps in artery reattachment (for example, T8 and T11 might be reattached, whereas T9 and T10 are not). The presence of the failed stent-graft can complicate aortic clamping. In patients with a failed TEVAR, the proximal clamp often needs to be placed between the left common carotid and left subclavian arteries. Hypothermic circulatory arrest (HCA) may be used when the wires of the stent-graft protrude well into the aortic arch or when aneurysm size precludes proximal aortic clamping.9 Although the potential need for HCA is often apparent from the preoperative imaging studies, at times the decision to use HCA is not made until direct intraoperative inspection. In patients with stent-graft failure, the surgeon should have a high degree of suspicion of stent-graft infection, even if the patient has no suggestive symptoms or signs. In cases of occult stent-graft infection, gross signs of infection, such as pus or necrotic tissue, may be discovered during surgery. On the other hand, inflammation is often observed surrounding the stent-graft even in patients without infection.13 In cases of suspected or documented infection, the stent-graft should be extracted completely.11,14,15 During repair, we favor using a polyester graft that has been soaked in an antibiotic, such as rifampin. Pedicled omental flaps are often used to wrap the new graft in an effort to reduce the risk of reinfection. Occasionally, an extra-anatomic approach might be justified to avoid recurrent graft infection. Transcutaneous catheters can be placed alongside the graft to enable postoperative antibiotic irrigation. Cultures of the excised graft material should be used to identify the infecting organism(s) and guide antibiotic therapy. These repairs necessitate a full postoperative course of intravenous antibiotics, and the patients often require lifelong suppressive therapy with oral antibiotics. Despite the best attempts at repair, long-term survival in patients with infection is greatly reduced, especially in cases with concomitant fistulae, such as aortoesophageal or aortobronchial fistulae.16–18 In patients without aortic infection, part of the stent-graft may be left in place, as long as a full thickness of the aortic wall surrounds—and preferably adheres to—the stent-graft to prevent excessive bleeding from needle holes. Wire-cutters are sometimes needed when one is cutting through the stent-graft. Proximally, it is important to recognize that the stent-graft might have been sutured directly to the aortic wall, as is commonly done in the frozen elephant trunk approach. Distally, relatively large portions of bifurcated abdominal stent-grafts may be left in place after the main body of the stent-graft is trimmed, particularly if the extension limbs are well adhered. These anastomoses are typically performed end-to-end and incorporate the stent-graft, the residual aortic wall, and the polyester replacement graft. In our experience, many patients who undergo stent-graft extraction are relatively young and without risk-enhancing comorbidities; consequently, the survival prognosis for patients without infection tends to be favorable.
Language: English
Field: Medicine
Open Access status: green
OpenAlex ID: W56286005
FWCI: 0.272
Cites: 17
Cited by: 5
Related to: 10