PubMed · 14734511
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Paolo Angelini, Scott Flamm. 2004-01-20. Nebulous imaging.. https://doi.org/10.1161/01.cir.0000111130.33177.0b
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BACKGROUND: Acute coronary occlusions leading to ST-segment elevation myocardial infarctions (STEMIs) are due primarily to rupture of atherosclerotic plaques. Present "vulnerable plaque" detection technology focuses on identifying individual plaques with no clear therapeutic plan beyond conventional risk factor reduction. We developed a spatial map of the distribution of acute coronary occlusions to test our hypothesis that plaque ruptures do not occur uniformly throughout the coronary tree. METHODS AND RESULTS: We analyzed 208 consecutive patients who presented to the Brigham and Women's Hospital with STEMI and mapped the location of the acute coronary occlusion. These occlusions were not uniformly distributed throughout each of the major epicardial coronary arteries but tended to cluster within the proximal third of each of the vessels (right coronary artery, P=0.001; left anterior descending artery, P=0.003; left circumflex artery, P=0.001). Furthermore, Poisson regression showed that for each 10-mm increase in distance from the ostium, the risk of an acute coronary occlusion was significantly decreased by 13% in the right coronary artery, 30% in the left anterior descending artery, and 26% in the left circumflex artery. CONCLUSIONS: Acute coronary occlusions leading to STEMI tend to cluster in predictable "hot spots" within the proximal third of the coronary arteries. Identification of these high-risk zones for acute coronary occlusions will lead to future advances in vulnerable plaque detection technology and potentially locally directed preventive strategies.
BACKGROUND: Angiography of the coronary arteries reflects only changes in luminal dimensions. With intravascular ultrasound, cross-sectional images can be obtained and area measurements can be added to calculate volumes of the external elastic membrane (EEM), plaque plus media (P+M), and lumen. The aim of this study was to investigate the effect of lipid lowering by simvastatin on coronary atherosclerotic P+M as changes in volumes of EEM, P+M, and lumen. METHODS AND RESULTS: In 40 male patients with hypercholesterolemia, ischemic heart disease, and a nonsignificant coronary artery lesion in a not previously revascularized coronary artery, serial intravascular ultrasound studies with an ECG-triggered pullback were performed at baseline, after 3 months on a lipid-lowering diet, and after another 12 months on simvastatin 40 mg/d. Mean length of the analyzed atherosclerotic segments was 5.9+/-3.3 mm. After 12 months on simvastatin, a significant reduction in P+M volume of 6.3% (P=0.002) was observed, whereas only a nonsignificant reduction in EEM volume of 1.8% was seen without any concomitant change in lumen volume. A significant reduction in total cholesterol of 31.0% (6.1+/-0.8 versus 4.2+/-0.7 mmol/L, P<0.001) and LDL cholesterol of 42.6% (4.0+/-0.8 versus 2.2+/-0.6 mmol/L, P<0.001) was obtained. CONCLUSIONS: Lipid-lowering therapy with simvastatin for 12 months is associated with a significant P+M regression in coronary arteries measured as reduction in P+M and EEM volumes without any concomitant change in lumen volume.
In the past decade, improvements in CT techniques have enabled non-invasive visualization of the coronary arteries. Multidetector CT (MDCT) is currently the generally accepted technique for the follow-up of coronary stents and by-pass grafts, and for the evaluation of anomalous coronary arteries and coronary artery disease. Both the degree of stenosis, as well as plaque composition can be determined by MDCT. Plaque composition has proven to be a more important predictor for acute coronary syndromes than the degree of stenosis. In addition, MDCT has less risks of complication and lower costs. Limitations of MDCT are: sensitivity to rhythm- and breathing artefacts, a lower spatial and time resolution than coronary angiography (CAG), and difficulties in coronary evaluation close to high density structures such as calcifications and stents. Coronary angiography is still indicated when functional information has to be obtained about coronary flow. MDCT should be considered in all cases in which diagnostic CAG is performed.