Acute Aortic Disease.. - Index of

Endovascular Thoracic Aortic Stent Grafting 281
prevalence is 0.5 and 2.95 per 100,000 per year. In the United States, it is estimated
that the prevalence is between 0.2 and 0.8 per 100,000 per year, resulting in
approximately 2000 new cases per year (10). These estimates may be low, with
one autopsy series demonstrating the antemortem diagnosis was made in only
15% of patients (11). Analysis that takes this factor into account results in an
estimate of approximately 6000 new cases per year in the United States.
The standard of care for the treatment of type A aortic dissection is surgical
therapy. The present surgical strategy is designed to prevent (i) rupture, (ii) heart
failure related to acute aortic valve insufficiency, (iii) coronary malperfusion,
and (iv) cerebral malperfusion, or stroke. Recent advances in surgical management
of acute type A dissection have resulted in significantly lower morbidity and
mortality. Recent series demonstrated mortality rates ranging from 9% to 25%
(12–19). Five-year survival following type A dissection repair ranges from 71% to
89% (13,17,20).
Proximal operative strategy (i.e., the choice of surgical technique for managing
the proximal end of the dissection) does not appear to have significant impact
on morbidity and mortality. Driever et al. (17) noted no difference in survival or
stroke rate when comparing aortic valve replacement (AVR) with supracoronary
ascending aortic replacement and valve resuspension with supracoronary aortic
replacement at five and 10 years. Lai et al. (16) similarly reported no difference
in six year survival between patients treated with composite valve conduit (65%),
AVR and supracoronary replacement (45%), and valve resuspension and supracoronary
aortic replacement (69%). In the largest reported single-center experience
(295 patients treated between 1990 and 2003 for acute type A aortic dissection),
Kallenbach et al. (13) showed no difference in outcome with respect to mortality,
neurological complications, and five year survival when comparing composite valve
conduit, supracommissural replacement, and valve-sparing aortic root replacement.
Due to the improved surgical outcome and the inherent complexity of
proximal repair, the application of endovascular aortic stent graft therapy has been
limited in acute type A dissection. A few case reports have demonstrated feasibility
of endovascular repair of type A dissection in a very small number of patients
(22–24). The role of endovascular stent graft therapy in the treatment of acute
type A dissection remains unclear.
In an adjunctive role, investigators have reported the concomitant use of an
aortic stent graft in the descending thoracic aorta during conventional open type A
dissection repair—in an effort to obliterate the distal thoracic dissection and prevent
chronic aneurysmal dilatation. The long-term results of these “hybrid”
procedures remain to be determined.
Type B Dissection
Although there is consensus that ascending aortic dissections should be managed
by urgent surgical repair, controversy currently exists regarding the optimal therapeutic
strategy for descending thoracic aortic dissections (Stanford type B).