I wish they would put a picture in here with pointer arrows.
Juxtaluminal Black Area in Carotid Artery Plaques May Predict Strokes
Researchers from the Imperial College Faculty of Medicine in London in
the United Kingdom (S Kakkos, M Griffin, A Nicolaides, E Kyriacou, M
Sabetai, T Tegos, G Geroulakos) revealed that the presence and size of a
juxtaluminal black (hypoechoic) area (JBA) on carotid ultrasound of
asymptomatic carotid artery plaques can predict the occurrence of
ipsilateral ischemic stroke. Their findings were explained today at the
66th Vascular Annual Meeting presented by the Society for Vascular
Surgery®.
Co-author Stavros K. Kakkos, MD, MSc, PhD, RVT,
who also is in the Department of Vascular Surgery at the University
Hospital of Patras in Patras, Greece, said that the JBA is associated
with a lipid core close to the lumen or a thrombus on the plaque surface
and is defined as an area of carotid plaque pixels with gray scale
median (GSM) value less than 25 which is adjacent to the vessel lumen
and lacks a visible echogenic cap, after image normalization of the
ultrasound plaque images.
This is the best I can find of images; unreadably pathetic.
The size of a JBA was measured in
the carotid plaque images of 1,121 patients with asymptomatic carotid
stenosis that was 50-99 percent in relation to the bulb which was
followed for up to eight years. “We confirmed that JBA had a linear
association with future stroke rate,” said Dr. Kakkos. “The area under
the ROC curve was 0.816. Using Kaplan Meier curves, the mean annual
stroke rate was 0.4 percent in 706 patients with a JBA size <4 mm2,
1.4 percent in 171 patients with JBA size 4-8 mm2, 3.2 percent in 46
patients with JBA size 8-10 mm2, and 5 percent in 198 patients with
JBA size >10 mm2 with a highly significant statistical significance
(P<.001).”
In multivariate analysis using a Cox model
with ipsilateral ischemic events (amaurosis fugax, transient ischemic
attack [TIA] or stroke) as the dependent variable, JBA (<4, 4-8,
>8, in mm2) was still significant after adjusting for other plaque
features known to be associated with increased risk. These include
stenosis, GSM, presence of discrete white areas without acoustic
shadowing (DWA) indicating neovascularization, plaque area and history
of contralateral TIA or stroke. However, plaque area and GSM were not
significant.
Using the significant variables (stenosis,
DWA, JBA and history of contralateral TIA or stroke), this model
predicted the annual risk of stroke (range 0.5-10.0 percent). The
average annual stroke risk was <1 percent in 734 patients; 1-1.9
percent in 94; 2-3.9 percent in 134; 4-5.9 percent in 125; and 6-10
percent in 34.
“The size of JBA is linearly related to the
risk of stroke and can be used in risk stratification models,” said Dr.
Kakkos. “These findings need to be confirmed in future prospective
studies or in the medical arm of randomized controlled studies in the
presence of optimal medical therapy.”
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