Discussion
Aortic dissections and aneurysms are rare complications in patients
with SLE; however, their incidence is higher in patients with SLE than
in age- and sex-matched controls1, 2. Patients with
SLE develop aortic aneurysms at a relatively early
age4. Pathological changes in patients with SLE
include cystic medial necrosis with mucopolysaccharide deposition and
Marfan-like changes, such as destruction of elastic
fibers5. Interestingly, histopathology results from
the present case showed a tear in the tunica media elastic fibers,
suggesting that this was the cause of the aortic dissection 17 years
previously. Various factors, other than atherosclerosis, have been
postulated to contribute to the formation of aortic aneurysms in
patients with SLE. Mucoid degeneration, vascular injury, hypertension,
arteriosclerosis, and steroid therapy are reportedly associated with
aneurysm formation 6. Long-term steroid therapy
inhibits chondroitin sulfate and granulation tissue formation, affecting
connective tissues and increasing the incidence of
atherosclerosis6, 7. The thoracic aorta is considered
more resistant to atherosclerosis than the abdominal aorta. The
difference in susceptibility to lipid deposition and subsequent plaque
formation suggests differences in the cellular and extracellular
compositions of the thoracic and abdominal aorta. This supports a
different pathophysiological mechanism for the development of TAA and
AAA8. Vasculitis and cystic medial degeneration
reportedly cause TAA, whereas atherosclerotic changes due to long-term
steroid therapy cause AAA in patients with SLE9. The
present case was of a TAA with severe atherosclerotic lesions. These
lesions and her early age suggest that the TAA may have been influenced
by SLE and steroid therapy.
The incidence of postoperative pseudoaneurysm after cardiac surgery is
estimated to be <0.5%10. Previous reports
include pseudoaneurysm occurring 1 year after acute aortic dissection
repair3, and true aneurysm recurrence 5 months after
AAA repair in SLE patients11. We should consider the
possibility of true aneurysms developing in patients with SLE even after
total arch replacement and consider using a technique that does not
leave the aortic wall short of the sino-tubular junction.