Introduction
The prevalence of diabetes mellitus (DM) in patients requiring cardiac
surgery is significantly increasing and achieving tight perioperative
glycemic control in DM patients could decrease perioperative morbidity
and improve survival [1-3] . Regarding aortic diseases,
current studies have demonstrated a negative correlation between DM and
the occurrence of aortic diseases [4-7] . However, previous
studies are contradictory in that patients with DM were found to have
poorer outcomes after abdominal aortic aneurysm repair [8],whereas mortality and clinical complications in type B aortic dissection
patients after thoracic endovascular aortic repair (TEVAR) were
significantly reduced in DM patients [9] . Whether patients
with aortic diseases may benefit from the tight glycemic control remains
unclear [10-11] .
DM has been shown to reduce the progression of aortic disease and the
pathophysiological explanation of these phenomena include: 1) increasing
the matrix of the aortic wall (suppression of plasmin and decreased
levels/activity of matrix metalloproteinase [MMP]) and 2) reducing
aortic mural macrophage infiltration and neovascularization[12] . The anti-inflammatory effect of oral antidiabetic
medication drugs (including metformin, sulfonylurea, and
thiazolidinedione) can also lower the risk of aortic aneurysm
development [13] . However, insulin treatment may diminish
this protective effect of hyperglycemia in preventing the aortic
aneurysm development process [14] . Therefore, it seems that
tight glycemic control (especially insulin treatment) is probably
unnecessary and harmful for DM patients with aortic diseases.
Acute aortic syndromes consist of three interrelated diseases: aortic
dissection, penetrating aortic ulcer and intramural hematoma (IMH).
According to the analysis from the International Registry of Acute
Aortic Dissection, fewer than 10% IMHA cases will resolve spontaneously
whereas 16% to 47% will progress to aortic dissection[15] . Complicated IMHA is defined as the presence of rapid
aortic expansion, signs of aortic rupture, fatal organ ischemia,
recurrent or refractory pain, and refractory hypertension despite
adequate medical therapy in the acute phase (≤14 days); immediate open
surgery is the first choice for these patients. However, for
uncomplicated IMHA patients, the ‘wait-and-watch strategy’ (optimal
medical therapy with blood pressure and pain control, serial imaging and
necessary TEVAR/surgery) is appropriate, particularly in the absence of
aortic dilation (>50 mm) and hematoma thickness less than
11 mm [16-17] . In Asian countries, the “wait-and-watch
strategy” is the first-line treatment for uncomplicated IMHA patients
with a maximum aortic diameter less than 50 mm and a hematoma thickness
less than 11 mm [18-20] . However, adverse clinical events
(development of aortic dissection, delayed surgery or death) that
develop within 6 months after medical treatment of uncomplicated IMHA
can reach a prevalence of 36.5% [18] which means that not
all uncomplicated IMHA patients may benefit from the “wait-and-watch
strategy”.
In sum, we hypothesized that in uncomplicated type A IMH patients who
received the “wait-and-watch strategy” (combined with tight glucose
management), patients with DM (compared with patients without DM) would
not benefit from such a treatment strategy because the
anti-hyperglycemia treatment would probably diminish the protective
effect of hyperglycemia in preventing aortic disease progression and the
obviously high adverse clinical events that develop within 6 months
after medical treatment of uncomplicated IMHA [1][18] .
To answer this question, we compared the clinical outcomes in
uncomplicated IMHA patients who received the “wait-and-watch strategy”
(with and without DM) during the first hospitalization and later
follow-up period.