Cath Lab Digest

Following Placement of a Thoracic Aortic Endograft: Successful Treatment with Carotid Subclavian Bypass

Introduction

Most traumatic thoracic aortic disruptions occur in the proximal descending thoracic aorta. A significant number of patients with thoracic aortic pathology are found to have disease adjacent to the origin of the great vessels. Endovascular treatment of these injuries often requires either partial or complete intentional coverage of the origin of the left subclavian artery (LSA) in order to obtain an adequate length of the proximal landing zone. The majority of these patients will not require subsequent revascularization of the LSA. There are, however, specific clinical situations where revascularization of the left subclavian and vertebral arteries may be required either prior to or following placement of the thoracic endograft.

Herein, we describe an unusual clinical case in which a dialysis-dependent man was treated with an endograft for a thoracic injury. The patient developed symptoms suggestive of vertebrobasilar insufficiency and diminished flow to a left upper extremity arteriovenous (AV) fistula. Subsequent revascularization of the LSA was required to restore adequate flow and function to the AV fistula. To our knowledge, this complication of LSA occlusion following endograft placement has not been described in literature.

Case Report

A 32-year-old was involved in a motor vehicle accident in which he was the restrained driver of a car that hit a barricade in a frontal collision. The patient was taken to another institution in town where he was found to have sustained a concussion and multiple rib fractures. Computed tomography (CT) revealed a thoracic aortic injury with a pseudoaneurysm along the lesser curvature of the proximal descending aorta. He underwent endovascular repair of the thoracic aortic injury with placement of a Gore Thoracic Aortic Endograft (TAG) 26 x 10 endoprosthesis (W.L. Gore & Associates, Inc, Flagstaff, Arizona). During follow-up imaging studies at the other institution, there was a question of an endoleak, and the patient was subsequently transferred to our institution for further management.

The patient’s past medical history is complex and significant for congenital glomerulonephritis. The patient has had renal failure for almost 20 years. He has had a total of 4 failed kidney transplants; the most recent of these was placed in 2005 and failed in 2006. Following this, the patient returned to hemodialysis via a left forearm AV fistula that had been patent and functional for about 19 years. His other medical history included hyperparathyroidism (status-post parathyroidectomy), atrial fibrillation, hypertension, and anemia of chronic kidney disease.

At our institution, a CT angiogram of the arch vessels confirmed a thoracic endograft with an endoleak filling the aortic pseudoaneurysm cavity at the level of the aortic isthmus along the lesser curvature. In addition, there was subtotal (~ 90%) occlusion of the origin of the LSA (Figure 1) and a patent, dominant left vertebral artery with a hypoplastic right vertebral artery.

At this time, the patient was noted to have diminished flow rates in the left forearm AV fistula on attempted hemodialysis, with decreased finger pressures when compared with the contralateral side. In addition, the dialysis unit reported trouble with cannulation of the fistula and frequent infiltration. A subsequent fistulogram demonstrated a patent, mature, left-forearm radiocephalic AV fistula with a few areas of mild stenosis and a patent central venous system on the ipsilateral side.

At the same time, the patient described perioral numbness, blurry vision, tinnitus, and decreased hearing in the left ear. These symptoms were suggestive of vertebrobasilar insufficiency.1

The patient subsequently underwent a left carotid-to-subclavian artery bypass with a 7 mm Dacron graft and ligation of the LSA proximal to the origin of the large left vertebral artery. The postoperative course was uncomplicated, and the patient was discharged home in good condition. Following revascularization of the LSA, the patient was noted to have resolution of the facial numbness, hearing changes, and blurry vision. In addition, the left forearm AV fistula now had a robust thrill. The dialysis flow rates and AV fistula function returned to pre-injury baseline. A CT angiogram performed 3 days postoperatively showed a patent left carotid-subclavian bypass with normal flow to the left vertebral artery and distal left subclavian and axillary arteries. In addition, the endoleak was noted to have resolved.

CT angiography performed at 6-month follow up (Figure 2) showed a well-placed endograft with no evidence of endoleak. The patient continues to do well. The AV fistula is functioning well, and he has had no recurrence of his neurologic symptoms.

Discussion

Endovascular management of aortic pathology has revolutionized the treatment of numerous disease processes, including degenerative aortic aneurysmal disease, aortic dissection, and traumatic aortic injury. Each of these disease processes presents unique anatomic challenges. Therefore, evaluation of the feasibility of treatment with a thoracic endograft should be conducted on a case-by-case basis.