Proximalization to zone 0/1- The further we advance
Though the FET has recently been implanted in zone 2, it is not without
challenges and complications. These challenges and complications may be
less as compared to implantation in zone3, but they still persists -
recurrent laryngeal nerve palsy (2.8% vs 5.2%, p=0.526), permanent
neurological defect (5.8% vs 9.9%, p=0.431), paraplegia (0 vs 4.7%,
p=0.191), bleeding (15.9% vs 12.2%,p=0.553) [9]. In the quest to
reduce the complication, newer technical devices are being introduced.
This necessitates the debranching of the supra-aortic arch vessels to
zone 0 and later implant the hybrid prosthesis in zone 0/1. Different
techniques to debranch the three supra-aortic vessels in the mediastinum
to Zone 0 are described - trifurcation arch graft with a perfusion side
arm port (TAPP graft, Vascutek Ltd., Renfrewshire, Scotland [10],
4-branched Dacron graft [11], Lupiae prosthesis (Vascutek Terumo
Inc, Scotland, UK) [12] or individual branch graft to each branch
vessel [13]. Among these ‘branch first’ techniques popularized by
Matalanis has a minimum DHCA time and reduced cardiopulmonary bypass
time [10]. With the advent of the neo E-vita and E-novia, the hybrid
prosthesis can be implanted in zone 0 to 3, and the supra aortic arch
vessels can be reimplanted individually, en bloc or just left in situ
with an uncovered stent graft
The advantages to implant the graft in zone 0/1 include (a)
proximalization of aortic arch to zone 0 (b) surgeons not familiar with
aortic arch and antegrade circulation can as well perform the procedure
with a brief period of DHCA after initial debranching (c) Can eliminate
the incidence of recurrent laryngeal nerve palsy and significantly
decrease paraplegia (d) The techniques allow a systematic interrogation
of each branch anastomosis ensuring secure hemostatic anastomosis (e)
Distal anastomosis is more proximal, enabling an easier hemostatic check
after the release of cross clamp.
Patients, who are sick with complex and very acute aortic dissection
including distal arch/proximal descending aorta re-entry tears, are not
suitable for total arch replacement or any complex surgery like FET as a
prolonged cardiopulmonary bypass time may be deleterious. These patients
may benefit from E-novia. The hybrid prosthesis consists of a distal
covered and proximal non-covered stent-graft portion. The covered
stent-graft is placed in the descending thoracic aorta while the
non-covered stent-graft is accommodated in the aortic arch. The proximal
anastomosis would be performed in Zone 0, eventually reducing the
ischemic time and hypothermic circulatory arrest time. This combines the
classic fast proximal aortic repair with the proposed downstream benefit
of the descending aorta in FET. The concept is similar to the PETTICOAT
experience in acute type B dissection where the branch vessel stays open
when there is adequate run off in the target vessel. The early result in
6 patients has been published recently [14], and discussed by
Roselli [15]. These are at present reserved for acute type I aortic
dissection, Penn B, C, BC, and patients with severe concomitant disease
[5].