Understanding coronary artery disease: tomographic imaging with intravascular ultrasound

In 1856 the pathologist Virchow published his now classic observations on atherothrombosis based on the examination of postmortem tomographic artery sections. The Virchow triad describes three components contributing to the atherothrombotic disease process: the vessel wall, the blood constituents, and blood flow. In vivo coronary imaging techniques became available more than 100 years later with the introduction of selective coronary angiography in 1958 by Mason Sones. Selective coronary angiography has allowed the identification of significantly stenotic, advanced coronary lesions and narrowed the clinical interest of cardiologists on luminal dimensions. This singular focus on angiographic stenosis has resulted in a proliferation of surgical and catheter based revascularisation techniques allowing mechanical treatment of focal coronary artery disease (CAD). Expressions like “fixing rusty pipes” and “plumbing”, used by cardiologist to describe atherosclerosis and its treatment, reflect a mechanistic view of CAD, based on the enormous success of these myocardial revascularisation techniques. However, Virschow's observations and more contemporary models of atherosclerotic disease have led to an understanding of CAD as a systemic disease of a complex organ system (the vessel wall) and its environment (the blood components and flow phenomena). Importantly, the complex atherosclerotic disease process is frequently not reflected in the luminal silhouette because most lesions have silently developed over a long time before they obstruct the lumen. Therefore direct imaging of the vessel wall has become a new goal in the assessment of CAD progression and prevention. Intravascular ultrasound (IVUS) represents the first clinical imaging technique enabling routine tomographic imaging of coronary arteries. Comprehensive technical and clinical reviews of IVUS have recently been published.1,2 In this article we will give a brief summary of IVUS techniques and then describe the role of tomographic coronary imaging for a contemporary understanding of CAD using examples from past and present experience with IVUS. …