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We report a rare case of Stanford type A acute aortic dissection involving an aberrant right subclavian artery and originating from Kommerell's diverticulum in a 52-year old man. Initially, as an emergency measure, total arch replacement and right axillary artery reconstruction were performed. However, due to the subsequent enlargement of the false lumen, thoracic endovascular aortic repair and right subclavian artery coiling were performed successfully 5 months after the first operation. Herein, we describe surgical management approaches for the treatment of a Stanford type A acute aortic dissection with aberrant right subclavian artery.
An aberrant right subclavian artery (RSCA) has been previously reported as a rare congenital anomaly, occurring in 0.5–2.0% of the population . Therefore, the Stanford type A acute aortic dissection (AAD) with aberrant RSCA is an exceedingly rare disease, which makes surgical planning for this condition in an emergency quite difficult. Here, we describe our experience with the surgical management of a Stanford type A AAD with aberrant RSCA in a case that was treated with a two-stage operation.
A 52-year old man, with a chief complaint of chest and back pain, was referred to our hospital for therapeutic management of Stanford type A AAD, which was previously diagnosed with a contrast-enhanced computed tomography (CT). His blood pressure was 97/59 mmHg using nitroglycerin. The performance status was good without digestive symptom and disturbance of consciousness. The contrast-enhanced CT scan showed an aberrant RSCA with an entry originating from Kommerell's diverticulum (Fig. (Fig.1).1). All cervical branches including aberrant RSCA were dissected, and all visceral branches branched off from true lumen without malperfusion. The aorta was dissected from sinus of Valsalva to bilateral common iliac artery, but aortic regurgitation was mild and coronary arteries were all intact. Minor axis of aorta was 40 mm at the distal aortic arch. Emergency surgery was performed on the same day, and the ascending aorta and total aortic arch were replaced using a 28-mm four-branched vascular graft (Triplex, TERUMO Co., Tokyo, Japan) via a median sternotomy during cardiopulmonary bypass. Firstly, an 8-mm prosthetic graft (Hemashield, Maquet, Rastatt, Germany) was anastomosed to the four-branched vascular graft beforehand for right axillary reconstruction. Cardiopulmonary bypass was established with direct true lumen cannulation. The patient was cooled down to 26°C and circulatory arrest was applied, then selective cerebral perfusion was performed. The RSCA was also perfused with a balloon cannula inserted via the origin. The entry was located at the base of the origin of the aberrant RSCA. As far as the risk of bleeding complication is concerned, it was considered that it would be safer to make the distal anastomosis between the left and right subclavian arteries rather than distal to the RSCA. To enable a thoracic endovascular aortic repair (TEVAR) if the false lumen would expand after the first operation, a landing zone space of >2 cm was secured on the proximal side of the aberrant RSCA for stent grafting. Lastly, the right axillary artery was reconstructed with an 8-mm graft that was anastomosed to the four-branched vascular graft.
The patient had well-controlled blood pressure and was discharged from our hospital as there was no false lumen enlargement on a follow-up CT 1 month after the first operation. However, at an outpatient visit after 3 months, rapid enlargement of the false lumen was observed on CT (Fig. (Fig.2A).2A). Therefore, a secondary operation was planned. Both TEVAR and aberrant RSCA coiling were performed as a staged operation. The course was good without any endoleaks and satisfactory remodelling of the descending aorta was achieved (Fig. (Fig.22B).
The Stanford type A AAD with the primary entry at the origin of an aberrant RSCA is a rare condition. To close the primary entry, this pathology can require total aortic arch replacement with the distal anastomosis distal to the origin of RSCA, total arch replacement with frozen elephant trunk technique or left thoracotomy approach to replace the whole arch and the descending aorta. However, big operation for AAD is often associated with a serious bleeding complication.
Previously, although some similar case reports have been presented, strategies or methods for treatment have varied among institutions [2–4]. In this patient, it was considered insecure to close the entry at the proximal descending aorta via a median sternotomy approach; therefore, only total aortic arch replacement and right axillary artery reconstruction was performed during the first operation. However, the decision to perform a secondary operation was made because of rapid enlargement of a false lumen. Therefore, even in the absence of initial enlargement of the false lumen, regular follow-up by CT scanning should be done.
At the time of the initial operation, we devised a procedure to secure a landing zone space for a stent graft more than 2 cm from the distal anastomosis, foreseeing a possibility for TEVAR if a secondary operation was needed. Although we had an option to perform distal aortic arch and descending thoracic aorta replacements via a left thoracotomy if TEVAR was not selected, we selected TEVAR in consideration of operative invasiveness. Despite a 5-month gap from the first to the second operation, the entry and false lumen disappeared after TEVAR. This case showed the possibility that remodelling of the dissected aorta can be achieved in cases with a large entry even if more than 5 months have elapsed from the initial surgery.
In summary, acute Stanford type A AAD with an aberrant RSCA was treated with a two-stage operation including an endovascular treatment at the second procedure. Total aortic arch replacement with consideration for the following endovascular treatment and close follow-up with CT was useful to save the patient from rupture of the enlarged aortic dissection.
Conflict of interest: none declared.