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