Branched Aortic Arch Study

An aneurysm is a localized bulge in the wall of an artery. Aneurysms of the aorta are prone
to progressive dilatation, which if left untreated ultimately results in rupture, internal
bleeding and death. Traditional open surgery involves aortic exposure through a long
incision, aortic clamping to interrupt blood flow, and replacement or repair of the dilated
aortic segment using a fabric conduit (graft), which is sutured (anastomosis) to the
nondilated arteries above and below the aneurysm. Some subjects are able to withstand such a
large operation better than others, but many suffer complications, and all suffer pain,
debility, and a lengthy stay in hospital.

Endovascular aneurysm repair is a less invasive alternative that substitutes a trans-arterial
route to the aneurysm for direct exposure, and stent-mediated attachment for sutured
anastomosis. Compared to open surgical repair, endovascular repair is associated with less
physiological derangement, less pain, less blood loss, lower complication rates and shorter
hospital stay. Consequently, endovascular repair has become standard therapy for aneurysms of
the abdominal aorta and descending thoracic aorta, where there are no vital branches and
endovascular exclusion rarely causes ischemic complications.

Open surgical repair of the proximal aortic arch requires hypothermic circulatory arrest,
because it deprives the heart of its outflow and the brain of its inflow. Endovascular repair
also obstructs outflow from the heart, but only for a few seconds, while the graft is
released from its delivery sheath. The greater problem is inflow to the brain. In
anticipation of aortic arch exclusion, the brachiocephalic circulation requires an
alternative source of blood. One alternative is bypass from the ascending aorta. However,
this requires median sternotomy and partial aortic clamping, both of with are potential
sources of morbidity.

Inclusion Criteria:

- Aneurysm of the aortic arch larger than 6cm in diameter, or symptomatic aneurysm of
the aortic arch, of any diameter, or any arch aneurysm with a 2-year rupture rate
estimated to be more than 20%.

- Anticipated mortality rate with open repair estimated to be more than 20%.

- Suitable arterial anatomy for stent-graft

- Life expectancy more than 2 years

- Ability to give informed consent and willingness to comply with follow-up schedule

Exclusion Criteria:

- Free rupture of the aneurysm

- Pregnancy

- Anaphylactic reaction to contrast material

- Allergy to stainless steel or polyester

- Unwillingness or inability to comply with the follow-up schedule

- Serious systemic or groin infection

- Uncorrectable coagulopathy

- Significant presence of carotid artery atherosclerosis

- Arrhythmia define as 2nd- and 3rd-degree atrioventricular block or sinus node disease,
such as sick sinus syndrome and symptomatic bradycardia, unless the patient already
has a pacemaker in place and cardiology consultation confirms that it is safe to
proceed.