Intravascular sensors to assess unstable plaques and their compositions: a review

Abstract

Atherosclerosis and its thrombotic complications plague developed countries. The rupture of vulnerable atherosclerotic plaques contributes to acute cardiovascular events and sudden cardiac deaths. Historically, coronary angiography has proved an invaluable tool for the detection and treatment of coronary stenoses which may result in myocardial ischemia; however, the method lacks the capacity to provide thorough information about properties of the lesion (i.e. whether it is lipid-rich, fibrotic, or calcified). The recent advances in electronics, biomaterials and microfabrication techniques have enabled novel multimodality catheters for the assessment of atherosclerotic plaques, such as the integration of intravascular ultrasound with photoacoustic microscopy, or optical coherence tomography, and the utilization of stretchable electrodes for electrochemical impedance spectroscopy. These pave the way for identification of complexity and composition of potentially unstable plaques as well as investigations of stenosis severity, plaque formation and remodeling, in both humans and studied animal models. However, up to date, an effective real-time detection of the atherosclerotic lesions prone to rupture which could be ready for clinical trials, remains an unmet challenge. In this context, this review highlights existing and newly-emerged intravascular sensors to assess metabolically and mechanically unstable plaques. Advantages and limitations, as well as further development and potential clinical applications will be thoroughly discussed.