Dye-Staining Angioscopy for Coronary Artery Disease

Novel imaging techniques using biomarkers have clarified the mechanisms of hitherto unanswered or misunderstood phenomena of coronary artery disease and enabled evaluation of myocardial blood and tissue fluid flows in vivo. Dye-staining coronary angioscopy using Evans blue (EB) as the biomarker can visualize fibrin and damaged endothelial cells, revealing that the so-called platelet thrombus is frequently a fibrin-rich thrombus; occlusive transparent fibrin thrombus, but not platelet thrombus, is not infrequently a cause of acute coronary syndrome; “fluffy” coronary luminal surface is caused by fibrin threads arising from damaged endothelial cells and is a residue of an occlusive thrombus after autolysis in patients with acute coronary syndrome without angiographically demonstrable coronary stenosis; and web or membrane-like fibrin thrombus is a cause of stent edge restenosis. Fluorescent angioscopy using visual or near-infrared light wavelengths is now used clinically for molecular imaging of the substances such as lipoproteins and cholesterol that constitute coronary plaques. Dye-staining cardioscopy using EB or fluorescein enables direct and real-time visualization of subendocardial microcirculation.