Surgical technique.
Surgical technique has been described in detail previously[4]. During the first stage, axillary cannulation is usually used for inflow for cardiopulmonary bypass, so as to avoid retrograde embolization of aortic debris under retrograde femoral perfusion. Under straight deep hypothermic arrest (DHCA) at 18°C during, aortic arch replacement is performed, with elephant trunk deployment. For the elephant trunk construction, a Dacron graft is brought to the surgical field and invaginated into itself. An anastomosis is performed between the aortic tissue and the full thickness of the invaginated graft, leaving the elephant trunk itself dangling in the descending aorta (Figure 2)[4]. The inner portion of the inverted elephant trunk is then everted and used for the aortic arch replacement. The arch vessels are then reconstructed and attached to the new Dacron aortic arch. Aortic Zone 2 was our preferred site for the aortic arch anastomosis (just before the left subclavian artery. During rewarming, the arch graft is sutured to the ascending aorta or to another graft replacing the ascending aorta. The patient is rewarmed and weaned from cardiopulmonary bypass.
During the second stage, typically 3 to 6 weeks later, a left thoracotomy or thoracoabdominal incision is made in a curvilinear fashion. In our institution, we prefer left atrial to femoral bypass for the Stage II procedure. Recently, we have switched from a centrifugal pump without oxygenator to the full heart-lung machine with an oxygenator for our descending and thoracoabdominal procedures [9]. When the distal aorta is clamped, bypass is instituted, and vertical aortotomy is done in the descending aorta at the level of the elephant trunk graft, which is then retrieved by the finger-thumb technique and clamped [10] (Figure 3). We then pull down gently on the elephant trunk, as a considerable longitudinal portion of the elephant trunk graft may still be up in the aortic arch. A proximal graft-to-graft anastomosis is performed to provide the required length of graft for reaching to the distal extent of the aortic resection. We perform the distal anastomosis and visceral anastomoses as required. The subclavian artery is transected and grafted (8 or 10 mm Dacron graft) during the Stage II procedure. The remaining aortic tissue is usually wrapped around the anastomosed graft, and the thoracotomy/thoraco-abdominal incision is closed in a standard fashion (Figure 4