Atherosclerotic coronary plaque in a patient with the metabolic syndrome: assessment by lesion physiology and intravascular ultrasound virtual histology

In vivo IVUS-based 3-D fluid-structure interaction models with cyclic bending and anisotropic vessel properties for human atherosclerotic coronary plaque mechanical analysis

In this paper, a modeling approach combining in vivo intravascular ultrasound (IVUS) imaging, computational modeling, angiography, and mechanical testing is proposed to perform mechanical analysis for human coronary atherosclerotic plaques for potential more accurate plaque vulnerability assessment. A 44-slice in vivo IVUS dataset of a coronary plaque was acquired from one patient, and four 3-D models with fluid-structure interactions (FSIs) based on the data were constructed to quantify effects of anisotropic vessel properties and cyclic bending of the coronary plaque on flow and plaque stress/strain conditions. Compared to the isotropic model (model 1, no bending, no axial stretch), maximum stress- P(1) (maximum principal stress) values on the cut surface with maximum bending (where applicable) from model 2 (anisotropic, no bending, no stretch), model 3 (anisotropic, with bending, no stretch), and model 4 (anisotropic with bending and stretch) were, respectively, 63%, 126%, and 345% higher than that from model 1. Effects of cyclic bending on flow behaviors were modest (5%-15%). Our preliminary results indicated that in vivo IVUS-based FSI models with cyclic bending and anisotropic material properties could improve the accuracies of plaque stress/strain predictions and plaque vulnerability assessment. Large-scale patient studies are needed to further validate our findings.

Electrical Immunoassays toward Clinical Diagnostics: Identification of Vulnerable Cardiovascular Plaque

A technology for electrical detection of protein biomarkers has been developed. It is based on developing high-density, low-volume multiwell plate devices. The scientific core of this technology lies in integrating nanoporous membranes with microfabricated chip platforms. This results in the conversion of individual pores into wells of picoliter volume. Specific antibodies are localized and isolated into individual wells. The formation of the antibody–antigen-binding complex occurs in individual wells. The membrane allows for robust separation among individual wells.

This technology has the capability to achieve near real-time detection with improved sensitivity and selectivity. This is due to the two factors associated with the technology: (1) event-based electrochemical detection process, where the individual step in the formation of the binding complex results in a specific change to the electrochemical conductance due to the pertubation of the electrical double layer at the base of the each well. (2) The nanoporous membrane is an electrical insulator and is structurally robust throughout hence there is improved signal-to-noise ratio and cross-contamination between is minimized.

Another advantage of this technique is the use of electrical signal in protein identification as compared to the use of optical methods; hence, it is a noninvasive and a label-free technique. The signal acquisition is simple and it uses the existing data acquisition and signal analysis methods.

We have demonstrated the use of this technology for addressing a specific clinical problem: identification of vulnerable coronary plaque in the perioperative state.