3. Results
In this prospective pilot study, 15 patients with symptomatic (7
patients, 47%) and asymptomatic carotid artery stenosis undergoing CEA
were included. Among symptomatic patients, 5 (71%) had recent stroke
and 2 (29%) had recent TIA with a median timing of the most recent
event of 6 weeks (IQR: 1-18) before the surgery (Table 1). Demographic
and clinical characteristics including risk factors, NASCET degree of
stenosis, medications and preoperative laboratory results are summarized
in Table 1. Symptomatic and asymptomatic patients did not significantly
differ in respect to preoperative characteristics. Symptomatic patients
had significantly higher hsCRP and D-dimer levels (p =0.016 andp =0.036, respectively). Mean NASCET degree of stenosis was higher
in the symptomatic as compared to the asymptomatic group (95%
[80-95] and 80% [76.3-83.8], p =0.021, respectively).
There was no significant difference in the length of hospitalization and
perioperative complications between the two groups, and only one patient
in the symptomatic group had an episode of perioperative TIA which has
recovered after the surgery.
Carotid plaque features detected on preoperative MRI scan are summarized
in Tables 2 and 3. Prevalence of unstable plaque was higher in
symptomatic than asymptomatic patients, although this was not
statistically significant (63% vs. 37%, p =0.077) (Table 2, Fig.
1). The most common type of carotid plaque as per modified AHA
classification was type IV-V (10 patients, 65%) (Table 3).
Differences between preoperative symptoms and histological and
immunohistochemistry features of carotid plaques are demonstrated in
Table 4. The expression of MMP-9 in CD68 cells within the carotid plaque
was found to be significantly higher in symptomatic as compared to
asymptomatic patients (86% vs. 25% with the highest expression,p =0.014). In the symptomatic group, 6 out of 7 plaque specimens
had the expression of MMP-9 in ≥5 clusters consisted of ≥20 cells or one
cluster ≥100 cells, while this was found only in one specimen in the
asymptomatic group (Table 4, Fig. 2 and 3). It was also higher in SMA
cells in symptomatic patients, but this did not reach statistical
difference (p =0.143). In addition, the average MVD by
immunohistochemical staining of CD34 was higher among the symptomatic
than asymptomatic patients (17 [6-23] vs. 6 [2.5-10], although
this did not reach significance (p =0.064). Similarly, lipid core
area was larger among the symptomatic than asymptomatic patients,
although it did not reach statistical significance (p =0.132).
Differences between MRI features of carotid plaques and histological and
immunohistochemistry features of carotid plaques are demonstrated in
Table 5. There were no significant differences between several
histological features and expression of MMP-9 between the patients with
unstable or stable carotid plaque detected by preoperative MRI, although
both the average MVD by immunohistochemical staining of CD34 and lipid
core area were somewhat higher among patients with unstable than stable
plaque. However, this was not significant (p =0.360 andp =0.569, respectively) (Table 5).