Echo-lucency of computerized ultrasound images of carotid atherosclerotic plaques are associated with increased levels of triglyceride-rich lipoproteins as well as increased plaque lipid content.
BACKGROUND
Echo-lucency of carotid atherosclerotic plaques on computerized ultrasound B-mode images has been associated with a high incidence of brain infarcts as evaluated on CT scans. We tested the hypotheses that triglyceride-rich lipoproteins in the fasting and postprandial state predict carotid plaque echo-lucency and that echo-lucency predicts a high plaque lipid content.


RESULTS
The study included 137 patients with neurological symptoms and > or = 50% stenosis of the relevant carotid artery. High-resolution B-mode ultrasound images of carotid plaques were computer processed to yield a measure of echogenicity (gray-scale level). Lipoproteins were measured before and hourly for 4 hours after a standardized fatty meal. A subgroup of 58 patients underwent endarterectomy. On linear regression analysis, echo-lucency (low gray-scale level) was associated with elevated levels of fasting and postprandial plasma triglycerides (P=.0002 and P=.002), IDL cholesterol (P=.0009 and P=.006), and VLDL/chylomicron remnant cholesterol (P=.0003 and P=.0004) and triglycerides (P=.0003 and P=.003), the area under the plasma triglyceride curve 0 to 4 hours after a fatty meal (P=.001), and body mass index (P=.0001). On ANCOVA, body mass index, fasting IDL cholesterol, and fasting plasma triglycerides were independent predictors of echo-lucency. Echo-lucency was associated with increased relative plaque lipid content (P=.02).


CONCLUSIONS
Increased plasma levels of triglyceride-rich lipoproteins predict echo-lucency of carotid plaques, which is associated with increased plaque lipid content. Because echo-lucency has been associated with a high incidence of brain infarcts on CT scans, triglyceride-rich lipoproteins may predict a plaque type particularly vulnerable to rupture.
Grønholdt
M L
ML
Department of Vascular Surgery, Rigshospitalet, University Hospital of Copenhagen, Denmark. mlg@rh.dk
Nordestgaard
B G
BG
Wiebe
B M
BM
Wilhjelm
J E
JE
Sillesen
H
H
D001161:Arteriosclerosis / Q000097:blood* / Q000000981:diagnostic imaging*; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D002340:Carotid Artery Diseases / Q000097:blood* / Q000000981:diagnostic imaging*; D008078:Cholesterol, LDL / Q000097:blood; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood*; D008074:Lipoproteins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D014280:Triglycerides / Q000097:blood*; D014463:Ultrasonography
D008078:Cholesterol, LDL; D008055:Lipids; D008074:Lipoproteins; D014280:Triglycerides