Abstract 2768: ApoA-1 is a Strong Determinant of Radial Artery Intima-Media Thickness as Measured by Ultrasound Biomicroscopy
Introduction: It is recognized that arteriosclerosis occurs in brachial artery and reflects systemic atherosclerosis burden including the coronary arteries. Flow mediated vasodilation as assessed in the brachial artery is also a predictor of coronary artery endothelial function. Using the newly developed ultrasound biomicroscopy (UBM) with a resolution down to 30μm, it is possible to non-invasively study the radial artery wall structure in detail.
Hypothesis: Radial artery intima-media thickness (IMT) correlates with established biomarkers for cardiovascular diseases and could be a potential imaging biomarker.
Methods:Seventy-four healthy volunteers (F/M: 43/31, age: 39±11 (SD) years) were recruited. UBM equipped with a 55 MHz scan head was used to image the bilateral radial arteries in a long-axis view at the level of the wrists. A 10sec CINE loop was stored for subsequent image analysis using the software package provided by the manufacturer. Blood samples were collected after overnight fasting and lipids, ApoA-1 and ApoB were measured using standardized assays. In a separate group of age-matched subjects (n=56), we validated the relationship between carotid and radial IMT, which resulted in r=0.5 (p<0.0001).
Results: Average radial artery IMT was negatively associated with ApoA-1 (r=-0.69, p<0.0001) and positively associated with ApoB (r=0.63, p<0.0001). Further, radial artery IMT was also moderately correlated to HDL and triglyceride (HDL: r=-0.4, p<0.001; TG: r=0.3, p=0.01). In a multivariate regression model, correcting for age, gender, HDL, TG, blood pressure, and ApoB, ApoA-1 remained the strongest independent predictor for radial artery IMT.
Conclusions:UBM-measured radial artery IMT is closely related to established serum biomarkers for cardiovascular diseases. With the unique spatial resolution of UBM and the non-invasive approach, the current imaging protocol could be a potential novel imaging biomarker for atherosclerosis.