[Intracoronary echocardiography: current perspectives].

Contrast angiography is presently the standard for in vivo quantitation and morphologic evaluation of coronary atherosclerosis. Pathologic-angiographic correlation studies have shown marked angiographic underestimation of atheromatous plaques. This is particularly true in the early stages of intimal thickening and atheroma growth where media initially enlarges to accommodate the proliferative process without a chance in lumen size. The miniaturization of transducers allowed to mount them on the tip of a catheter and made it possible to position these catheters inside the arterial lumen and, for the first time, to see in vivo the vessel wall. Intravascular ultrasound is a new imaging technique with the ability to define and measure luminal areas and arterial wall components; therefore it serves as a potential tool to assess vascular wall morphology and dynamic vasomotor responses in epicardial coronary arteries. Its ability to measure luminal areas and diameters and the different components of the arterial wall has been validated by several in vitro, animal and in vivo studies. The definition of normal arterial wall by ultrasound has been defined looking at coronary arteries of young adults. It also showed that young subjects with angiographically normal vessels have a wide range of coronary intimal thickening, including occasional evidence of focal, early atheromatous lesions. Safety studies have shown it does not accelerate progression of angiographically quantifiable coronary artery disease suggesting that it can be safely utilized even in coronary arteries not undergoing interventions. The large potential of intracoronary imaging in the setting of interventional cardiology and future developments are also discussed, including the use of combined devices (ultrasound catheter-balloon angioplasty, ultrasound-atherectomy, ultrasound-laser); three dimensional reconstruction; new devices design, such as looking forward catheters; tissue characterization with the goal of differentiating between different types of plaque, and between soft plaque and thrombus; study of biomechanical properties of the atherosclerotic plaque, trying to distinguish between "good" and "bad" plaques. In conclusion, intravascular ultrasound is a powerful in vivo coronary imaging technique which may serve as a new standard for quantifying coronary atherosclerosis and offers significant potential for enhancing our understanding of the pathophysiology of coronary artery disease.