TITLE

Vulnerable Plaques by CT

AUTHOR(S)
Abrams, Jonathan
PUB. DATE
September 2007
SOURCE
Clinical Cardiology Alert;Sep2007, Vol. 26 Issue 9, p70
SOURCE TYPE
Periodical
DOC. TYPE
Article
ABSTRACT
THE INCREASING USE OF 64-SLICE COMPUTED tomography or MSCT is beginning to significantly impact the medical literature. This study, from Japan; Irvine, California; and Gaithersburg, Maryland, is an early effort of utilizing MSCT to evaluate "vulnerable" coronary arteries that could cause an acute coronary syndrome (ACS). Coronary Plaque Evaluation by MSCT: The authors suggest that a ruptured coronary plaque is likely to be very similar in composition to a vulnerable, but non-ruptured plaque that has yet to become eroded or rupture, and that such imaging signatures can be assessed using high-quality imaging technology to identify lesions that are at high risk for causing a subsequent coronary event. While interest in plaque composition and imaging is very high at the present time, it remains unclear if current imaging capability allows for detection of a variety of important plaque characteristics. There are numerous catheter-based technologies and techniques being applied to help answer important questions relating to plaque vulnerability. These include optical coherence tomography, intravascular magnetic resonance, thermography, and most familiar, intravascular ultrasound or IVUS. The authors state, "Recent improvements in CT technology and the advent of multislice computed CT have spurred interest in non-invasive detection of morphologic characteristics of vulnerable plaques." This study began in 2004 with the utilization of 0.5mm X 16- slice CT; 56 of the 71 ACS patients enrolled had no further imaging; 15 individuals were added to the original cohort, resulting in a total of 71 patients; the latter group all had 64-slice imaging. The cohort was derived from screening of 441 patients. Individuals were classified as having stable or unstable angina, as well as acute coronary syndrome (ACS), which was defined by elevation of troponin or unstable angina pectoris. Stable angina patients with single vessel disease who had undergone a coronary angiogram were studied. STEMI patients were included if they were evaluated greater than 24 hours from the onset of chest pain and were symptom free. Coronary angiograms were used to identify the culprit lesion as well as to define other angiographic parameters. Of the 71 patients, 10 had STEMI, 9 had NSTEMI, 19 had unstable angina, and 33 had stable angina. Invasive procedures were performed on a majority of the patients. The MSCT protocol utilized is highly technical; readers interested in tomography details should refer to the article. Characteristics identified and analyzed include coronary artery remodeling (positive remodeling relates to increase in coronary artery diameter at a plaque site that is at least 10% larger than the adjacent reference segment). Plaques were analyzed by the presence or absence of calcification as well as IVUS analysis. Spotty and large calcifications were analyzed. Vessels were assessed as to presence of soft or fibrous plaque. Only patients imaged with the 64-slice unit were included for an IVUS analysis. Individuals who interpreted this study were blinded to clinical status. Sensitivity, specificity, positive/negative predictive values, and diagnostic accuracy were assessed for each vessel. Results: All 71 patients had comparable baseline characteristics (age, gender, or presence of diabetes/hypertension/hyperlipidemia, smoking and obesity). Positive expansive remodeling was noted in the large majority of culprit lesions (87%). Spotty calcification was noted in 63%. Culprit lesions had a large lipid core, with calcification seen in 22%. Stable angina patients demonstrated a low likelihood of positive remodeling, and plaques characterized as soft.…
ACCESSION #
26599314

 

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