Use of Intravascular Ultrasound in Interventional Cardiology

Abstract

For the last 60 years, coronary angiography remains the investigation of choice to evaluate coronary artery disease. Coronary angiography, however, only provides a two-dimensional “luminogram” of a three-dimensional arterial structure. As a result, its interpretation is subjected to interobserver variability and may be compounded by vessel overlapping and tortuosity. Intravascular ultrasound (IVUS), on the other hand, is a catheter-based technique which provides a comprehensive assessment of the entire vessel wall, including the extent and distribution of the atherosclerotic plaque. Owing to its high resolution, IVUS has been used extensively in various clinical and research settings. Some of the IVUS diagnostic applications include assessment of angiographically intermediate lesions particularly in the left main coronary artery. The use of IVUS at times may result in redirection of therapeutic management. IVUS is also extremely valuable in guiding percutaneous revascularisation strategies, especially in the case of left main coronary artery disease. It allows detailed pre-intervention evaluation of the target artery as well as post-intervention assessment of procedural outcome. This information is ultimately critical for the clinician to devise an appropriate procedural strategy to optimise clinical outcome. In atherosclerosis research, IVUS has provided a significant insight into the understanding of the natural history of atherosclerosis. The serial IVUS-measured atheroma change has been widely used as a surrogate end point in various pharmacological clinical trials. The development of new IVUS technology, such as virtual histology IVUS or combined IVUS with near-infrared spectroscopy has allowed further characterisation of atherosclerotic plaque, which may ultimately impact cardiovascular outcome.