Patrick Donnelly

Assessment of coronary plaque progression in coronary computed tomography angiography using a semiquantitative score.

OBJECTIVESnWe sought to describe the progression of coronary atherosclerotic plaque over time by computed tomography (CT) angiography stratified by plaque composition and its association with cardiovascular risk profiles.nnnBACKGROUNDnData on the progression of atherosclerosis stratified by plaque composition with the use of noninvasive assessment by CT are limited and hampered by high measurement variability.nnnMETHODSnThis analysis included patients who presented with acute chest pain to the emergency department but initially showed no evidence of acute coronary syndromes. All patients underwent contrast-enhanced 64-slice CT at baseline and after 2 years with the use of a similar protocol. CT datasets were coregistered and assessed for the presence of calcified and noncalcified plaque at 1 mm cross sections of the proximal 40 mm of each major coronary artery. Plaque progression over time and its association with risk factors were determined. Measurement reproducibility and correlation to plaque volume was performed in a subset of patients.nnnRESULTSnWe included 69 patients (mean age 55 +/- 12 years, 59% male patients) and compared 8,311 coregistered cross sections at baseline and follow-up. At baseline, any plaque, calcified plaque, and noncalcified were detected in 12.5%, 10.1%, and 2.4% of cross sections per patient, respectively. There was significant progression in the mean number of cross sections containing any plaque (16.5 +/- 25.3 vs. 18.6 +/- 25.5, p = 0.01) and noncalcified plaque (3.1 +/- 5.8 vs. 4.4 +/- 7.0, p = 0.04) but not calcified plaque (13.3 +/- 23.1 vs. 14.2 +/- 22.0, p = 0.2). In longitudinal regression analysis, the presence of baseline plaque, number of cardiovascular risk factors, and smoking were independently associated with plaque progression after adjustment for age, sex, and follow-up time interval. The semiquantitative score based on cross sections correlated closely with plaque volume progression (r = 0.75, p < 0.0001) and demonstrated an excellent intraobserver and interobserver agreement (kappa = 0.95 and kappa = 0.93, respectively).nnnCONCLUSIONSnCoronary plaque burden of patients with acute chest pain significantly increases during the course of 2 years. Progression over time is dependent on plaque composition and cardiovascular risk profile. Larger studies are needed to confirm these results and to determine the effect of medical treatment on progression.

Association between diabetes and different components of coronary atherosclerotic plaque burden as measured by coronary multidetector computed tomography

OBJECTIVEnThe aim of the study was to assess differences in the presence, extent, and composition of coronary atherosclerotic plaque burden as detected by coronary multidetector computed tomography (MDCT) between patients with and without diabetes mellitus.nnnMETHODSnWe compared coronary atherosclerotic plaques (any plaque, calcified [CAP], non-calcified [NCAP, and mixed plaque [MCAP]]) between 144 symptomatic diabetic and non-diabetic patients (36 diabetics, mean age: 54.4+/-12, 64% females) who underwent coronary 64-slice MDCT (Siemens Medical Solutions, Forchheim, Germany) for the evaluation of acute chest pain but proven absence of myocardial ischemia.nnnRESULTSnPatients with diabetes had a higher prevalence of any plaque, CAP, MCAP, and NCAP (p=0.08, 0.07, 0.05, and 0.05, respectively) and a significantly higher extent of any plaque, CAP, MCAP, and NCAP (3.8+/-4.2 vs. 2.0+/-3.2, p=0.01; 3.3+/-4.0 vs. 1.7+/-3.0, p=0.03; 1.4+/-2.6 vs. 0.6+/-1.5, p=0.03; and 1.9+/-3.0 vs. 1.0+/-1.9, p=0.03, respectively) as compared to controls. In addition, patients with diabetes had a significant higher prevalence of significant coronary artery stenosis (42% vs. 14%, p=0.0004) and an approximately 3.5-fold higher risk of significant coronary stenosis independent of the presence of hypertension and BMI (OR: 3.46, 95% CI: 1.37-8.74, p=0.009).nnnCONCLUSIONnPatients with diabetes have an approximately 3.5-fold higher risk of coronary stenosis independent of other cardiovascular risk factors and an overall increased coronary atherosclerotic plaque burden.

Multimodality imaging atlas of coronary atherosclerosis.

NEW HIGH-RESOLUTION IMAGING TECHNOLOGIES HAVE ENHANCED OUR UNDERSTANDING OF THE CORONARY atherosclerotic disease process, and this atlas provides a multimodality pictorial review of the development of histologically verified coronary atherosclerosis. A modified American Heart Association

Correlation of concentrations of high-sensitivity troponin T and high-sensitivity C-reactive protein with plaque progression as measured by CT coronary angiography

BACKGROUNDnElevated levels of inflammatory biomarkers are associated with increased cardiovascular morbidity and mortality.nnnOBJECTIVEnWe sought to determine whether elevated concentrations of high-sensitivity troponin T (hs-TnT) and high-sensitivity C-reactive protein (hs-CRP) predict progression of coronary artery disease (CAD) as determined by coronary CT angiography (coronary CTA).nnnMETHODSnPatients presenting to the emergency department with acute chest pain who initially showed no evidence of an acute coronary syndrome underwent baseline and follow-up coronary CTA (median follow-up, 23.9 months) using identical acquisition and reconstruction parameters. Coronary CTA data of each major coronary artery were co-registered. Cross-sections were assessed for the presence of calcified and noncalcified plaques. Progression of atherosclerotic plaque and change of plaque composition from noncalcified to calcified plaque was evaluated and correlated to levels of hs-TnT and hs-CRP at the time of the baseline CT.nnnRESULTSnFifty-four patients (mean age, 54.1 years; 59% male) were included, and 6775 cross-sections were compared. CAD was detected in 12.2 ± 21.2 cross-sections per patient at baseline. Prevalence of calcified plaque increased by 1.5 ± 2.4 slices per patient (P < .0001) over the follow-up period. On average, 1.6 ± 3.6 slices with new noncalcified plaque were found per patient (P < .0001) and 0.7 ± 1.7 slices with pre-existing noncalcified plaque had progressed to calcified plaque (P < .0001). After multivariate adjustment, change of overall CAD burden was predicted by baseline hs-TnT and hs-CRP (r = 0.29; P = .039 and r = 0.40; P = .004). Change of plaque composition was associated with baseline hs-TnT (r = 0.29; P = .03).nnnCONCLUSIONnConcentrations of hs-TnT and hs-CRP are weakly associated with a significant increase in CAD burden and change in plaque composition over 24 months independent of baseline risk factors.

Accuracy of dual-source computed tomography in quantitative assessment of low density coronary stenosis--a motion phantom study.

PurposeWe assessed the accuracy and reproducibility of non-calcified plaque quantification as simulated by a low-density stenosis in vessel phantoms using diameter and area measures, as well as the influence of vessel size and motion on quantification accuracy in dual-source computed tomography (DSCT).MethodsFour phantoms (2, 2.5, 3, and 4xa0mm in luminal diameter) made from a radiopaque Lucite (126u2009±u200923 Hounsfield units, HU) simulating a fixed radiolucent concentric coronary stenosis (7u2009±u20092 HU, 50% luminal narrowing) were connected to a cardiac motion simulator. Stenosis quantification was based on area and diameter measurements. All measurements were highly reproducible (all ICCu2009≥0.95, pu2009<u20090.001).ResultsThe mean measured degree of stenosis was 38.0u2009±u200911.7% for a single diameter measurement, resulting in a mean relative error of 22.0u2009±u200918.7%, decreasing with increasing phantom size (31.9u2009±u200922.1%; 25.2u2009±u200920.9%; 16.3u2009±u200912.8%; 14.5u2009±u200911.4%; for 2-, 2.5-, 3-, and 4-mm phantoms, respectively; pu2009<u20090.0001). Measurement accuracy significantly increased to 13.3u2009±u200913.9% by using area measurement (pu2009<u20090.0001). The degree of stenosis was not significantly different when comparing a motioned image with an image at rest.ConclusionDSCT enables highly reproducible quantification of low density stenosis, but underestimates the degree of stenosis, especially in small vessels. Area-based measurements reflect the true degree of stenosis with higher accuracy than diameter.

Computed tomography versus invasive coronary angiography: design and methods of the pragmatic randomised multicentre DISCHARGE trial

AbstractObjectivesMore than 3.5 million invasive coronary angiographies (ICA) are performed in Europe annually. Approximately 2 million of these invasive procedures might be reduced by noninvasive tests because no coronary intervention is performed. Computed tomography (CT) is the most accurate noninvasive test for detection and exclusion of coronary artery disease (CAD). To investigate the comparative effectiveness of CT and ICA, we designed the European pragmatic multicentre DISCHARGE trial funded by the 7th Framework Programme of the European Union (EC-GA 603266).MethodsIn this trial, patients with a low-to-intermediate pretest probability (10–60xa0%) of suspected CAD and a clinical indication for ICA because of stable chest pain will be randomised in a 1-to-1 ratio to CT or ICA. CT and ICA findings guide subsequent management decisions by the local heart teams according to current evidence and European guidelines.ResultsMajor adverse cardiovascular events (MACE) defined as cardiovascular death, myocardial infarction and stroke as a composite endpoint will be the primary outcome measure. Secondary and other outcomes include cost-effectiveness, radiation exposure, health-related quality of life (HRQoL), socioeconomic status, lifestyle, adverse events related to CT/ICA, and gender differences.ConclusionsThe DISCHARGE trial will assess the comparative effectiveness of CT and ICA.Key Points• Coronary artery disease (CAD) is a major cause of morbidity and mortality.n • Invasive coronary angiography (ICA) is the reference standard for detection of CAD.n • Noninvasive computed tomography angiography excludes CAD with high sensitivity.n • CT may effectively reduce the approximately 2 million negative ICAs in Europe.n • DISCHARGE addresses this hypothesis in patients with low-to-intermediate pretest probability for CAD.

Cardiac Computed Tomography

Computed tomography (CT) is one of the greatest innovations of the twentieth century, and it has revolutionized clinical practice. Sir Godfrey Hounsfield, an English engineer working for EMI, and Allan Cormack of Tufts University, Massachusetts, a South African-born physicist, developed the concept and the first computed axial tomographic (CAT) scanner in 1972. For the first time, a large volume of data could be collected in an orthogonal plane by using a thin X-ray beam to rotate around a region of interest. The earliest scanners took hours to acquire data and several days to reconstruct the final image for analysis. Subsequent advances such as “slip-ring” technology removed the need for a rigid mechanical linkage between the power cables and the X-ray tube. This enabled the X-ray tube to rotate indefinitely and resulted in spiral CT. CT imaging has become a cornerstone of clinical practice, and it is thought that over 62 million CT scans are performed each year in the USA