Hybrid Endovascular and Off-Pump Open Surgical Treatment for Synchronous Aneurysms of the Aortic Arch, Brachiocephalic Trunk, and Abdominal Aorta

Abstract

A 71-year-old patient was admitted for synchronous aneurysms of the aortic arch, brachiocephalic trunk, and juxtarenal abdominal aorta involving the iliac arteries. The patient first underwent open surgical repair of the juxtarenal abdominal aortic aneurysm by means of aorto-bifemoral bypass. Three months later, he underwent off-pump surgical repair of the aneurysm of the brachiocephalic trunk and bypass grafting from the ascending aorta to the brachiocephalic trunk and the left common carotid artery, followed by successful exclusion of the aneurysm of the aortic arch by deployment of a Zenith TX1 custom-made endograft, inserted through a limb of the aorto-bifemoral graft.

Combined endovascular and open surgical treatment is an appealing new alternative to open surgical repair for complex aortic diseases. Debranching of the aortic arch enables endovascular grafting in this area, thereby avoiding cardiopulmonary bypass and circulatory arrest. Staged and simultaneous procedures should be considered for the treatment of complex aortic diseases even in poor-risk patients; however, due to the investigative characteristics of these procedures, patient selection and postoperative follow-up should be carried out with utmost attention.

Endovascular grafting of the thoracic aorta is gaining widespread acceptance for treating an array of aortic diseases, due to its reduced invasiveness.^1,2 The more invasive the standard open treatment is, the more appealing becomes the endovascular alternative; however, there are still limitations, such as an aneurysmal neck of inadequate size for attachment of the graft and sealing of the aneurysm.

In regard to proximal extension of the thoracic aortic disease into the aortic arch, it has been shown that the left subclavian artery can be covered safely by the endograft and that its revascularization is only rarely needed. The left common carotid artery has also been covered by endograft in order to use the segment of aortic arch between the left common carotid artery and the left subclavian artery as a proximal neck; this can be safely accomplished only if revascularization of the left common carotid artery has been previously accomplished.^3,4

Involvement of the brachiocephalic trunk and of the proximal aortic arch obliges the clinician to make choices, namely the source of inflow for revascularization of the supra-aortic trunk and the selection of a graft with the ability to navigate to the proximal aortic arch and be released there.

Conventional open surgical treatment of aneurysms that involve the entire aortic arch and the proximal brachiocephalic trunk usually requires cardiopulmonary bypass (CPB) and hypothermic circulatory arrest. Endovascular treatment associated with surgical revascularization of the supra-aortic trunks enabled us to successfully treat this complex case with reduced invasiveness.

Case Report

A 71-year-old man was admitted to our institution for synchronous aneurysms of the aortic arch, brachiocephalic trunk, and juxtarenal abdominal aorta. His relevant medical history included hypertension, severe chronic obstructive pulmonary disease, and tobacco use. He had dysphonia in association with left vocal cord paralysis (which in turn was probably caused by compression of the recurrent laryngeal nerve by the aneurysm).

Computed tomography (CT) (Fig. 1A) and magnetic resonance angiography (MRA) (Fig. 1B) showed the postero-inferior extension of the aneurysm of the arch and defined its dimension (transverse diameter, 7.8 × 7 cm). An aneurysm of the origin of the brachiocephalic trunk (3.2 cm), coiling of the right internal carotid artery, and kinking of the left internal carotid artery were also shown. The juxtarenal abdominal aortic aneurysm (AAA) had a transverse diameter of 8 cm and involved both the common iliac arteries.

Fig. 1 Axial computed tomographic (A) and multiplanar magnetic resonance angiographic (B) scans show multiple aneurysms involving the aortic arch and the brachiocephalic trunk (arrow).

The patient first underwent surgical resection of the juxtarenal AAA and implantation of a bifurcated aorto-bifemoral Dacron graft (Hemashield, Platinum 22 × 11 mm, Meadox Medicals, Inc.; Oakland, NJ). Recovery from this operation was slow, so 3 months passed before the patient was readmitted for treatment of the aneurysm of the aortic arch.

Hybrid endovascular treatment was planned in order to avoid hypothermic circulatory arrest, thereby maintaining direct cerebral perfusion through the supra-aortic vessels. A Zenith TX1 cone-shaped endograft (William Cook Europe; Bjaeverskov, Denmark) was custom-made (194 × 42 × 36 mm) to fit the differing dimensions of the ascending and descending aorta. The tapered tip of the delivery system, which is usually 8 cm long, was reduced to 4 cm in our custom-made device in order to minimize interference with the aortic valve and left ventricle. The procedure was performed in the operating room under fluoroscopic guidance, with use of a portable C-arm image intensifier with digital subtraction angiography (OEC Medical Systems, Inc., series 9600; Salt Lake City, Utah). The right brachial artery was cannulated with a 6F introducer for diagnostic angiography.

The procedure was performed under general anesthesia, supplemented by epidural analgesia. Cerebral activity was monitored by means of continuous intra-operative electroencephalography (EEG).

The 1st stage of the procedure was surgical “debranching” of the aortic arch. A median sternotomy was performed, and the ascending aorta and supra-aortic trunks were isolated; heparin was administered (5000 UI). The ascending aorta was side-clamped, and a proximal end-to-side anastomosis was performed with a bifurcated Dacron graft (Hemashield, Platinum 12 × 7 mm), positioned with the limbs facing up.

The left common carotid artery was test-clamped and no anomalies were recorded by EEG; the artery was then ligated proximally and transected. An end-to end anastomosis with a branch of the bifurcated graft was performed. Similarly, the brachiocephalic trunk was test-clamped distally, and no EEG anomalies were observed. The aortic arch was side-clamped, including the aneurysmal origin of the brachiocephalic trunk. The brachiocephalic trunk was transected and an end-to-end anastomosis was performed with the other limb of the graft. The proximal aneurysmal part of the brachiocephalic trunk was resected, and the continuity of the aortic arch was restored with a suture, which was reinforced with Teflon felts.

A proximal neck of sufficient length was thus obtained in the proximal arch and ascending aorta for endovascular stent grafting (Fig. 2). The right limb of the aorto-bifemoral graft (implanted in the previous operation for AAA) was exposed in the groin and cannulated. A standard guidewire was advanced into the left ventricle and replaced with an extra-stiff guidewire (Back-up Meier, Boston Scientific Corporation; Miami, Fla). The endograft was advanced up to the arch. At this time, the patient experienced an asystolic cardiac arrest. Cardiac resuscitation was immediately performed by means of direct cardiac massage and intravenous administration of 2 mg of adrenaline. Spontaneous and effective cardiac activity was promptly restored, and the procedure was completed uneventfully. In spite of the reduction in length of the tapered tip of the delivery system, the probable cause of the life-threatening arrhythmia was either the stiff guidewire or the endograft.

Fig. 2 Intraoperative view after revascularization of the supra-aortic trunks and resection of the aneurysm of the brachiocephalic trunk. Note the guidewire ring positioned as the proximal radiologic marker.

The endograft was successfully deployed, which completely excluded the aneurysm (Figs. 3A and 3B). Completion aortography was performed from the ascending aorta, which had been cannulated through the right brachial artery and the bypass graft, and showed a satisfactory result (Fig 3C). Transesophageal echocardiography (Fig. 4A) showed immediate slowing of the flow (smoke effect) in the sac and, within a few hours, thrombus formation.

Fig. 3 A) Angiogram shows the aneurysm of the arch after repair of the aneurysm of the brachiocephalic trunk and bifurcated grafting of the supra-aortic trunks. B) The radiopaque marker enabled precise release of the endograft without use of iodinated contrast medium. C) Note complete exclusion of the aortic arch with the thoracic stent-graft.

Fig. 4 Postoperative transesophageal echocardiogram (A) shows slowing of the flow, or “smoke effect.” Computed tomographic scans in axial (B) and sagittal (C) views show complete thrombosis of the aneurysmal sac and correct positioning of the endograft in the aortic arch, without endoleak. The bifurcated graft to the brachiocephalic vessels is also shown (arrow).

After surgery, the patient was transferred to an intensive care unit, and he was moved to the surgical ward on postoperative day 4. The postoperative course was complicated by atrial fibrillation and by pulmonary atelectasis and effusion on postoperative days 2 and 3, respectively, which regressed after medical therapy, including intravenous administration of amiodarone, antibiotic agents, and diuretic agents. Postimplantation syndrome (pain, fever, leukocytosis, and decreased platelet count) was not observed. Postoperative CT showed satisfactory placement of the endograft with complete thrombosis of the aneurysmal sac (Figs. 4B and 4C). The patient was discharged in good clinical condition on postoperative day 8. At his 3-month follow-up, he was doing well.

Discussion

Hypothermic circulatory arrest is the preferred method to treat aortic arch aneurysms. However, deep hypothermia is associated with prolonged extracorporeal circulation and with increased mortality and morbidity rates due to microemboli production and to total body inflammatory reaction—particularly coagulopathy, respiratory distress, and renal, cardiac and endothelial dysfunction.^5,6 An alternative method that avoids CPB and hypothermic circulatory arrest would clearly benefit the patient.

Endovascular grafting has proved a safe and effective alternative to conventional surgical treatment of aneurysms of the aortic arch, partly because it avoids CPB. The problem of the lack of an adequate proximal neck for safe fixation of the endograft may be solved by “lengthening the branchless descending thoracic aorta” by means of surgical revascularization of the supra-aortic vessels, as pointed out by Criado and coworkers^3,4 in 2002; according to their “map” of the aortic arch, the zone proximal to the brachiocephalic trunk (“zone 0”) is technically the most challenging.

A completely extrathoracic revascularization of the supra-aortic vessels could be achieved by using the femoral artery as the inflow vessel, as proposed by Ishimaru (see Criado⁴); however, the ascending aorta may be a safer and more durable source of inflow to the cerebral vessels. Buth and colleagues⁷ in 1998 reported retrograde endovascular grafting of the distal aortic arch after ascending aorta-to-left common carotid and left subclavian artery bypass with a bifurcated graft.

Other authors have reported debranching the aortic arch to enable a stent-graft to land in “zone 0” of the aortic arch. Nitta and associates⁸ reported previous revascularization of the supra-aortic vessels with a trifurcated graft from the ascending aorta, performed under extracorporeal circulation and antegrade cerebral perfusion; this does not seem to us to be necessary, since a temporary occlusion of one of the supra-aortic vessels is usually well tolerated, and an intraluminal shunt can be used if an EEG shows inadequate tolerance by the brain.

A complex case of ruptured aortic arch aneurysm in a very sick patient was reported by Drenth and co-authors.⁹ The patient was treated successfully with off-pump coronary bypass grafting, ascending aorta-to-brachiocephalic and left common carotid bypass with a bifurcated graft, and endovascular grafting of the aortic arch with 2 Gore Excluder® thoracic grafts.

Dietl's group¹⁰ reported 2 cases in which there had been previous replacement of the ascending aorta for type A dissection with aneurysmal dilatation of the arch; in these patients, Dietl and colleagues performed a bypass from the ascending aortic graft to the brachiocephalic trunk and left common carotid artery, then performed endovascular grafting of the arch with Gore stent-grafts.

Chuter and coworkers¹¹ reported their use (landing in zone 0) of an interesting modular branched stent-graft for endovascular repair of aortic arch disease; it enables preservation of the brachiocephalic trunk, provided that this vessel is of normal size.

In treating our patient, we were challenged by the simultaneous presence of 3 distinct aneurysms. A staged approach seemed sensible due to the severity of the lesions. The AAA was treated first with an open operation; thus we were able to overcome problems posed by the short proximal neck and by the iliac aneurysms, while gaining a safe access route for subsequent deployment of the endograft. The 2nd procedure was delayed due to the slow recovery of the patient; ideally, it should be performed as soon as possible in order to reduce the risk of rupture of the thoracic aneurysm during the interval between the 2 operations.¹²

The revascularization of the supra-aortic vessels and the closure of the aneurysm of the brachiocephalic trunk were safely accomplished without CPB, by means of aortic side-clamping and controlled hypotension. The intraoperative placement of a radiopaque marker at the desired landing site enabled precise deployment of the graft without use of additional contrast medium for aortography.

Moreover, we were able to show that the commercially available Zenith TX1 graft is indeed suitable for delivery and deployment in this zone. The normal difference in size between the ascending and descending thoracic aorta makes it desirable to use a tapered conical endograft, thus avoiding a problematic mismatch between the diameter of the distal stent and that of a tubular endograft suited to the ascending aorta.

In conclusion, the synergy between open surgery and endovascular procedures extends the indications for use of endovascular grafting, even to the most challenging areas, such as zone 0 of the aortic arch. Staged and simultaneous procedures should be considered for the treatment of complex aortic diseases even in poor-risk patients; however, due to the investigative characteristics of these procedures, patient selection and postoperative follow-up should be carried out with utmost attention.

Acknowledgments

The authors would like to thank Michael John, coordinator of the English courses in the Faculty of Medicine and Surgery at the Vita-Salute San Raffaele University, for his suggestions regarding the linguistic aspects of this paper. They also gratefully acknowledge Dr. Giovanni La Canna for performing transesophageal echocardiography on this patient.