The use of adjunctive stents to maintain the patency of critical branches of the aorta has variously been called the “kissing stent,” “chimney,” “double barrel,” or “snorkel” technique.1–3 These have been advocated as alternatives until specific fenestrated and/or branch grafts are more readily available to maintain patency of critical side branches and to allow endografts to be placed more proximally in more favorable landing zones. Although most often described for juxtarenal aneurysms, as a method of preserving the renal arteries in particular, this approach has been used for the thoracic great vessels and for a wide variety of pathologies.1,3–9 However, questions remain regarding the risk of endoleak and stroke in these procedures and the optimal type of grafts to use.
A 75-year-old Vietnamese gentleman presented with a 3-day history of severe right upper quadrant pain, chills, and rigors, followed by new-onset intrascapular and left neck pain and hoarseness and coughing while swallowing. His medical history was notable for hepatitis B and C, past alcohol dependency, portal hypertension, gout, tuberculosis, chronic obstructive pulmonary disease, and chronic renal insufficiency (admission serum creatinine level, 2.2 mg/dL). He was cachetic and weak and appeared malnourished. Serum albumin level was 2.6 g/dL (reference range, 3.5–4.8 g/dL); protein level, 5.5 g/dL (reference range, 6.1–7.9 g/dL); and transferrin level, 122 mg/dL (reference range, 215–365 mg/dL). He had no history of notable chest trauma. Computed tomographic angiogram demonstrated a large aneurysm arising from the origin of the left subclavian artery and extensive pleuro-parenchymal scarring (Fig. 1). The patient’s leukocyte count was 20,000/μL, and he had previously been noted to have a common duct stone, although this was not documented at this admission. Within 24 hours of receiving parenteral antibiotics, his leukocyte count dropped, liver functions normalized, his chills resolved, and it was felt that he had experienced transient cholangitis. Blood cultures were negative, as were venereal disease research laboratory and rapid plasma reagin. A carotid and vertebral ultrasound revealed no significant carotid disease, and transcranial Doppler confirmed an intact posterior Circle of Willis. He did, however, describe worsening neck and posterior chest pain.
We did not feel that the patient would tolerate open repair and thus offered him the choice of endovascular repair or medical management, and he chose the former. To get even a minimal proximal landing zone, the origin of the left common carotid would have to be covered (Fig. 2). The patient underwent preprocedural hydration using sodium bicarbonate, and his creatinine level had improved to 0.9 mg/dL. The endovascular repair consisted of an open exposure of the right common femoral artery, placing distally a 31 mm × 31 mm × 10 cm Gore-Tag (W.L. Gore, Flagstaff, AZ, USA) to provide stability, and then advancing a 34 mm × 34 mm × 10 cm C-TAG (W.L. Gore) proximally. Simultaneously, a left carotid exposure was performed and accessed with a 7F sheath. Advancing the C-Tag was difficult because it would get caught up in the proximal lip of the aneurysm. Ultimately, by advancing an end snare through the carotid to give added stability, we were able to advance the graft. We then deployed an 8 mm × 5 cm Viabahn (W.L. Gore) graft into the origin of the thoracic aorta, trying to match it up with the proximal extent of the thoracic endograft. Unfortunately, in removing the deployment device, the stent was inadvertently pushed into the ascending aorta. This was retrieved, while maintaining wire access, using an end snare and withdrawing into the access sheath, which was then replaced into the femoral artery. Another Viabahn was placed in the carotid artery, and gentle “kissing” ballooning was performed. To complete the procedure, the left subclavian artery was coil embolized proximal to the origin of the left vertebral artery. Completion angiogram demonstrated no endoleak and retrograde left vertebral flow (Fig. 3). Total procedural time was 245 minutes, fluoroscopy time was 65 minutes, and the amount of contrast agent used was 240 mL. The starting hematocrit level was 31%, and the patient received a total of 1 unit of packed red blood cells throughout the procedure and did not require any postprocedure.
The patient was extubated the next day and required 3 days of hospitalization. At 2 months’ follow-up, the aneurysm was sealed; although there is an inferior “bird’s beak,” the carotid duplex shows no obstruction to flow (Fig. 4). The patient’s hoarseness, swallowing disorder, and intrascapular pain have resolved, although he still has neck pain felt to be caused by cervical arthropathy. At 7 months’ follow-up, the aneurysm had completely resolved (Fig. 5).
When landing a thoracic endograft in the distal arch, assessment of what constitutes an adequate landing zone must take into account not only the distance to the aneurysm but also the distance to the maximal angulation of the arch-descending aortic junction. The forces acting on the thoracic aorta and, therefore, the endograft are greatest in the area where the arch turns and descends.10 The role of kissing stents, in which branch vessel patency is maintained by laying a stent parallel to the main endograft, has been championed as a reasonable alternative in certain cases, primarily in patients with an increased risk of stroke or when the landing zone needs minimal extension.10 One of the concerns regarding this approach has been the risk of endoleak arising between the gutters of the side-by-side stents. Although studies suggest that sufficient remodeling occurs by both the grafts and aortic walls, it has been stressed that the seal zone should be considered distal to the point where the paired grafts come into apposition.3,11 In addition, depending on the acuity of the angle that a given branch stent graft must traverse, the greater the concern of graft occlusion. The more kissing stents required, the greater these concerns become.
The specific role of stenting the left common carotid artery to extend the landing zone has been described. In a partial review of the literature, we found reports of 33 cases, including a mixture of bare and covered self-expanding and balloon-expanded stents used for a wide variety of aortic pathology. Approximately one half were placed for inadvertent coverage of the origin of the carotid. Most cases were approached using direct carotid exposure; the remainder, using a variety of extrathoracic bypasses that were in place. It has been commented, and our experience is in concordance, that it is extremely difficult to gain sufficient purchase to the left common carotid artery from a right brachial approach. Two (6%) patients experienced stroke (one fatal), two (6%) required operative repair (one for persistent type I endoleak, one for persistent aneurysmal expansion), and one (3%) had type I endoleak that had resolved.3,4,6–9,12,13 Follow-up was limited, but one of the larger series, reported by Shu and colleagues,8 noted no complications at 6 to 15 months after the procedure.
Alternative strategies have included a variety of great vessel debranching, including ascending aortic to great vessel (with or without left subclavian anastamosis), or extrathoracic debranching, including carotid-carotid, carotid-carotid-subclavian, or/left carotid-subclavian bypass—all designed to extend the landing zone.14 These would have been technically feasible in this case, but the patient’s degree of malnourishment, overall weakness, pleural scarring, and his other comorbidities suggested to us that the least invasive approach was the safest. In addition, the patient already had pulmonary dysfunction and vocal cord paresis. There is a small incidence of pharyngeal dysfunction and recurrent nerve injury with the retropharyngeal carotid-carotid bypass route, and we were worried that this could lead to significant pulmonary issues if this occurred. Other approaches under investigation include the use of laser-assisted in situ fenestration, but this is not available at our institution.15 In addition, our preprocedure transcranial Doppler demonstrated that the risk of posterior circulation stroke was minimal. If we had determined that maintaining the left subclavian flow was critical to preserve posterior circulation, then we would have considered a left carotid-subclavian bypass or a combined kissing stent approach that included the left subclavian artery.
We believe that our case illustrates four important points. The first is that a team capable of both open and endovascular approaches assessed the risk/benefit of both approaches. Second, preoperative evaluation determined that the risk of stroke was not increased by excluding the subclavian artery, simplifying the procedure. Third, the left common carotid origin tends to arise at an angle from the arch that, in this case, did not require it to cross an acute angle. Finally, the team needs to have advanced skill in access and wire and catheter manipulation. Even a team that feels it is skilled can have complications that should be preventable. In this case, special skills were required to manage the complication of the stent graft being dislodged into the arch, as well as simply traversing the arch with the endograft.
Although the promised advent of true hybrid stent grafts should diminish the need for kissing stents, they will not diminish the need for a team that can comprehensibly evaluate patients and offer all possible approaches to repair. In patients who do not have prohibitive operative risks and the anatomy is not favorable for endovascular solutions, we still recommend debranching as appropriate and as an adjunct to endovascular repair or formal open repair. In high-risk patients, these approaches offer an alternative, albeit at the risk of less than completely satisfying results.
1. Schlosser FJ, Aruny JE, Freiburg CB, Mojibian HR, Sumpio BE, Muhs BE. The chimney procedure is an emergently available endovascular solution for visceral aortic aneurysm rupture. J Vasc Surg
. 2011; 53: 1386–1390.
2. Greenberg RK, Clair D, Srivastava S, . Should patients with challenging anatomy be offered endovascular aneurysm repair? J Vasc Surg
. 2003; 38: 900–906.
3. Baldwin ZK, Chuter TAM, Hiramoto JS, Reilly LM, Schneider DB. Double-barrel technique for preservation of aortic arch branches during thoracic endovascular repair. Ann Vasc Surg
. 2008; 22: 703–709.
4. Criado FJ. A percutaneous technique for preservation of arch branch patency during thoracic endovascular repair (TEVAR). J Endovasc Ther
. 2007; 14: 54–58.
5. Hiramoto JS, Chang CK, Reilly LM, Schneider DB, Rapp JH, Chuter TAM. Outcome of renal artery stenting for renal artery coverage during endovascular aortic aneurysm repair. J Vasc Surg
. 2009; 49: 1100–1106.
6. Ma H, Yang H-Y, Zou J-J, Zhang X-W. Management with insufficient proximal landing zone for endovascular repair in aortic dissection. Chin Med J
. 2011; 124: 3003–3007.
7. Ohrlander T, Sonesson B, Ivancev K, Resch T, Dias N, Malina M. The chimney graft: a technique for preserving or rescuing aortic branch vessels in stent graft sealing zones. J Endovasc Ther
. 2008; 15: 161–165.
8. Shu C, Luo MY, Li M, Wang T, He H. Early results of left carotid chimney technique in endovascular repair of acute non-A-non-B aortic dissections. J Endovasc Ther
. 2011; 18: 477–484.
9. Wang GJ, Woo EY. Snorkel procedures for TEVAR. Endovasc Today.
10. Figueroa CA, Taylor CA, Chiou AJ, Yeh V, Zarins CK. Magnitude and direction of pulsatile displacement forces acting on thoracic aortic endografts. J Endovasc Ther
. 2009; 16: 350–358.
11. Bruen KJ, Feezor RJ, Daniels MJ, Beck AW, Lee WA. Endovascular chimney technique versus open repair of juxtarenal and suprarenal aneurysms. J Vasc Surg
. 2011; 53: 895–905.
12. Gehringhoff B, Torsello G, Pitoulias GA, Austerman M, Donas KP. Use of chimney grafts in aortic arch pathologies involving the supra-aortic branches. J Endovasc Ther
. 2011; 18: 650–655.
13. Sugiura K, Sonesson B, Akesson M, Bjorses K, Holst J, Malina M. The applicability of chimney grafts in the aortic arch. J Cardiovasc Surg (Torino)
. 2009; 50: 475–481.
14. Bergeron P, Coulon P, DeChaumaray T, et al.. Great vessel transposition and aortic arch exclusion. J Cardiovasc Surg
. 2005; 46: 141–147.
15. Murphy EH, Dimaio JM, Dean W, Jessen ME, Arko FR. Endovascular repair of acute traumatic thoracic aortic transection with laser-assisted in-situ fenestration of a stent-graft covering the left subclavian artery. J Endovasc Ther
. 2009; 16: 457–463.
Keywords:Copyright © 2012 by the International Society for Minimally Invasive Cardiothoracic Surgery. Unauthorized reproduction of this article is prohibited.
Thoracic endograft; Kissing stents; Snorkel; Thoracic aneurysm