The composition of vulnerable plaque and its effect on arterial waveforms

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Medical Diagnostics

Background:

• Carotid plaque composition significantly impacts plaque stability and patient prognosis.
• Unstable plaques feature a thin fibrous cap (FC) and large lipid core (LC), while stable plaques have thicker FC and less LC.
• Accurate identification of plaque composition aids surgical treatment decisions.

Purpose of the Study:

• To establish a non-invasive method for distinguishing between stable and unstable carotid plaques.
• To define the relationship between plaque composition and arterial waveform characteristics.

Main Methods:

• An in-vitro artificial arterial system with a pulsatile flow pump simulated carotid artery conditions.
• Five plaque types (LC, FC, Collagen, Calcium) were introduced into a 30% blocked artificial carotid artery.
• Pulsatile pressure, velocity, and arterial wall movement were measured proximal to the plaque.
• Non-invasive wave intensity analysis (Non-WIA) separated waveforms into forward and backward components.

Main Results:

• Reflected arterial waveforms strongly correlate with carotid plaque composition.
• Collagen percentage showed a linear correlation with backward diameter amplitude (r=0.74).
• Lipid content exhibited a strong negative correlation with backward diameter (r=-0.82).
• Calcium percentage showed a weak correlation with reflected waveforms.

Conclusions:

• Arterial waveform components can quantitatively distinguish between different carotid plaque compositions.
• This correlation suggests a potential for a novel non-invasive clinical tool.
• Such a tool could enable early detection and differentiation of stable and vulnerable carotid plaques.