Introduction
Methods
Sample population
Histopathological examinations
Definitions of histopathological indices and semi-quantification of histopathological observations
Characteristics | Score | |||
---|---|---|---|---|
1 | 2 | 3 | 4 | |
Plaque rupture | Plaque intact | Plaque probably intact or artefactual break in the fibrous cap due to surgical incision | Plaque probably ruptured; the site of rupture is not clearly visible, though a thrombus adherent to lipid is present in the lumen | Definitely ruptured plaque |
Thrombus | Absent | Small | Large | |
Lipid core | Absent | Small; < 25% of the overall plaque area | Large; ≥ 25% of the overall plaque area | |
Fibrous tissue | Minimal | ≤ 50% of all tissue | > 50% of all tissue | |
Inflammatory cells | Absent | Occasional cell or 1 group of > 50 cells per section | 2–5 groups of > 50 cells per section | >5 groups of > 50 cells or 1 group of > 500 cells per section |
Foamy macrophages | Absent | < 50 cells per section | ≥50 cells per section | |
Intraplaque hemorrhage | Absent | Small | Large | |
Calcification | Absent | Stippling only | Calcified nodules | |
Intraplaque microvessels | Absent | < 10 per section | ≥10 per section | |
Overall instability | Definitely stable; predominantly fibrous plaque with thick, intact fibrous cap | Probably stable; single sign of instability, such as small hemorrhage or inflammation | Probably unstable; signs of instability present, such as inflammation, < 200 µm minimum fibrous cap thickness and large lipid core without rupture | Definitely unstable; presence of rupture, thrombus, large hemorrhage, inflammation and < 200 µm minimum fibrous cap thickness |
Magnetic resonance imaging
Statistical analysis
Results
Clinical characteristics
Group 1 (n = 66) | Group 2 (n = 13) |
P
| |
---|---|---|---|
Age (years) | 73.8 ± 7.0 | 71.6 ± 5.4 | 0.213 |
Men | 58 (88) | 13 (100) | 0.412 |
Diabetes mellitus | 26 (39) | 4 (31) | 0.785 |
Hypertension | 49 (74) | 11 (85) | 0.656 |
Dyslipidemia | 53 (80) | 13 (100) | 0.180 |
Chronic kidney disease | 17 (26) | 3 (23) | 0.884 |
Current smoker | 19 (29) | 7 (54) | 0.151 |
History of: | |||
Transient ischemic attack or cerebral infarction | 13 (20) | 4 (31) | 0.604 |
Coronary artery disease | 9 (14) | 3 (23) | 0.657 |
Peripheral artery disease | 3 (5) | 1 (8) | 0.636 |
Prior drug therapy | |||
Aspirin | 5 (8) | 3 (23) | 0.234 |
Clopidogrel | 4 (6) | 1 (8) | 0.825 |
Cilostazol | 1 (2) | 0 (0) | 0.655 |
Days between stroke onset and carotid endarterectomy | 50 ± 45 | 39 ± 33 | 0.384 |
Baseline laboratory results | |||
Glucose (mg/dl) | 135 ± 50 | 137 ± 48 | 0.904 |
Cholesterol (mg/dl) | |||
Low-density lipoprotein | 121 ± 32 | 105 ± 37 | 0.118 |
High-density lipoprotein | 52 ± 12 | 51 ± 14 | 0.934 |
Low-density/high-density lipoprotein cholesterol | 2.5 ± 0.9 | 2.2 ± 1.1 | 0.371 |
Triglycerides (mg/dl) | 147 ± 74 | 187 ± 71 | 0.083 |
Patient number | Statin | mg/day | Duration of therapy |
---|---|---|---|
1 | Pitavastatin | 1.0 | ≥ 1 year |
2 | Rosuvastatin | 2.5 | ≥ 1 year |
3 | Rosuvastatin | 2.5 | 8 months |
4 | Pravastatin | 10.0 | ≥ 1 year |
5 | Pitavastatin | 1.0 | ≥ 1 year |
6 | Rosuvastatin | 2.5 | 11 months |
7 | Rosuvastatin | 2.5 | ≥ 1 year |
8 | Rosuvastatin | 2.5 | ≥ 1 year |
9 | Rosuvastatin | 2.5 | ≥ 1 year |
10 | Rosuvastatin | 2.5 | ≥ 1 year |
11 | Rosuvastatin | 10.0 | ≥ 1 year |
12 | Rosuvastatin | 2.5 | 6 months |
13 | Atorvastatin | 5.0 | ≥ 1 year |
Histopathological plaque characteristics
Group 1 (n = 66) | Group 2 (n = 13) |
P
| |
---|---|---|---|
Plaque rupture | 2.82 ± 0.77 | 2.36 ± 0.48 | 0.009 |
Lumen thrombus | 1.97 ± 0.42 | 1.69 ± 0.32 | 0.009 |
Lipid core | 2.89 ± 0.24 | 2.79 ± 0.32 | 0.193 |
Fibrous tissue | 2.38 ± 0.36 | 2.49 ± 0.35 | 0.319 |
Inflammatory cells | 3.64 ± 0.48 | 3.31 ± 0.48 | 0.008 |
Foamy macrophages | 2.84 ± 0.29 | 2.67 ± 0.41 | 0.088 |
Intraplaque hemorrhage | 2.75 ± 0.39 | 2.49 ± 0.46 | 0.030 |
Calcifications | 2.43 ± 0.62 | 2.72 ± 0.40 | 0.113 |
Intraplaque microvessels | 2.88 ± 0.23 | 2.59 ± 0.34 | < 0.001 |
Overall instability | 3.29 ± 0.38 | 3.13 ± 0.26 | 0.098 |
Comparison of infarct volume in group 1 versus group 2
Correlation between infarct volume and histopathologic plaque characteristics in patients presenting with strokes
Infarct volume | |||
---|---|---|---|
r
|
r
2
|
P
| |
Lumen thrombus | 0.265 | 0.070 | 0.032 |
Plaque rupture | 0.203 | 0.041 | 0.102 |
Lipid core | 0.051 | 0.003 | 0.684 |
Fibrous tissue | − 0.055 | 0.003 | 0.663 |
Inflammatory cells | 0.124 | 0.015 | 0.321 |
Foamy macrophage | 0.119 | 0.014 | 0.340 |
Intraplaque hemorrhage | 0.035 | 0.001 | 0.783 |
Calcification | − 0.011 | < 0.001 | 0.929 |
Intraplaque microvessels | 0.125 | 0.016 | 0.317 |
Overall instability | 0.106 | 0.011 | 0.398 |