Coronary CT Angiography: Evaluation of Stenosis and Occlusion
Once an atherosclerotic plaque has been identified and properly characterized by means of coronary CT angiography (CTA), the next step is to define the extent of atherosclerotic involvement, i.e., significant reduction of the lumen by stenosis or complete occlusion of the vessel. A reduction in the caliber of the vessel lumen is associated with a reduction in blood flow and may have significant hemodynamic consequences; however, an important and clearly evident parietal atherosclerotic plaque may be present without significantly reducing lumen caliber. Thus, an exact definition of the extent of lumen reduction by means of coronary CTA is very important from a clinical point of view. In most cases, this diagnostic procedure is employed in not highly symptomatic patients (in patients in whom there is strong clinical suspicion of coronary disease, catheter angiography is directly performed); then, depending on the results of the clinical examination, a decision is made as to whether a more invasive approach (catheter angiography) is required. This decision depends at least in part on the significance of the vessel stenosis. The aim and key role of coronary CTA is to differentiate patients with normal coronary vessels from those with limited atherosclerotic involvement without evidence of stenosis (who may benefit from supportive drug therapy) and from those with significant stenosis. In this latter group, catheter coronary angiography may confirm the significance of the disease and define the therapeutic approach.
KeywordsAtherosclerotic Plaque Left Anterior Descend Collateral Circulation Vessel Lumen Significant Stenosis
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