High-intensity Statin Treatment Is Associated with Reduced Plaque Structural Stress and Remodelling of Artery Geometry and Plaque Architecture

Aims Plaque structural stress (PSS) is a major cause of atherosclerotic plaque rupture and major adverse cardiovascular events (MACE). We examined the predictors of changes in peak and mean PSS (ΔPSSpeak, ΔPSSmean) in three studies of patients receiving either standard medical or high-intensity statin (HIS) treatment. Methods and results We examined changes in PSS, plaque size and composition between 7,348 co-registered baseline and follow-up virtual-histology intravascular ultrasound images in patients receiving standard medical treatment (controls, n = 18) or HIS (atorvastatin 80mg, n = 20, or rosuvastatin 40mg, n = 22). The relationship between changes in PSSpeak and plaque burden (PB) differed significantly between HIS and control groups (p < 0.001). Notably, PSSpeak increased significantly in control lesions with PB > 60% (p = 0.04), but not with HIS treatment. However, ΔPSSpeak correlated poorly with changes in lumen and plaque area or PB, plaque composition or lipid lowering. In contrast, ΔPSSpeak correlated significantly with changes in lumen curvature, irregularity and roughness (p < 0.05), all of which were reduced in HIS patients. ΔPSSmean correlated with changes in lumen area, PA, PB, and circumferential calcification, and was unchanged with either treatment. Conclusion Our observational study shows that PSSpeak changes over time were associated with baseline disease severity and treatment. The PSSpeak increase seen in advanced lesions with standard treatment was associated with remodelling artery geometry and plaque architecture, but this was not seen after HIS treatment. Smoothing plaques by reducing plaque/lumen roughness, irregularity and curvature represent a novel mechanism whereby high-intensity statins may reduce PSS, and thus may protect against plaque rupture and MACE.

An Initial Effort to Create a Superficial Femoral Artery Ultrasound Phantom Using 3-Dimensional Printing

Three-dimensional (3D) printing of anatomical structures has yielded valuable models for simulation, education, and surgical planning applications. Applications for 3D printing have continued to expand to include some ultrasound applications. The goal of this effort was to evaluate if a 3D printed model of a superficial femoral artery (SFA) would have realistic ultrasound characteristics. A computed tomography scan was 3D reconstructed and segmented using TeraRecon Aquarius Intuition software (TeraRecon, Foster City, California) to obtain an atherosclerotic SFA geometry. Both the lumen geometry and calcified plaque geometry of the SFA were exported as a stereolithographic (STL) file. The STL file was printed with An Object350 Connex 3D System using 2 different materials selected based on published elastic modulus data. VeroWhite was selected for the calcified plaque and TangoPlus Clear was selected for the artery wall. After printing, the SFA model was imaged in a water bath with a Phillips IU22 duplex ultrasound console and L12-9 ultrasound probe. Ultrasound imaging of the SFA model yielded grayscale views of artery geometry. Lumen geometry of the SFA model was similar to the actual artery geometry. Ultrasound was able to discern between the 3D print materials and visualize regions with stenosis. Suboptimal ultrasound parameters of echogenicity and wave velocity noted to differ from biological tissue. Total 3D print material cost was estimated at below $20. Although the 3D printed model did not have fully accurate ultrasound characteristics, it still provided realistic imaging. With further research, 3D printed models may offer a low-cost alternative for ultrasound phantoms.

Influence of the Realistic Artery Geometry Parameters on a Coronary Stent Fatigue Life

The stents’ adaptability and safety in realistic and idealized stenotic coronary model were compared to investigate the influence of artery geometry parameter on stent fatigue life. The stents’ fatigue resistance ability was calculated using Goodman diagram, and the cycle to failure, the fatigue life, and the fatigue safety factor (FSF) were analyzed. Although the peak top of the von Mises stress was located at the bending area of crowns, the stress distributions were different in the two models. Considering the safety and accuracy, it is necessary to use a realistic geometric model to calculate the stent fatigue performance.

Longitudinal study of carotid artery bifurcation geometry using magnetic resonance angiography

Background and purpose Carotid artery geometry has been suggested as a risk factor for atherosclerotic carotid disease. Although normal aging and disease development can both lead to geometric changes in the arteries, the exact nature of this phenomenon remains elusive. The aim of our study was to investigate carotid artery geometric changes in a longitudinal study. Material and methods We conducted a retrospective study of 114 subjects who underwent carotid contrast-enhanced magnetic resonance angiography at our clinic at baseline (2005 to 2007) and after 10 years. The right ( Rev#2–1) carotid arteries were segmented using semi-automated methods to obtain various measurements of carotid artery geometry. For each patient, these parameters were assessed at both time points, including bifurcation angle, internal carotid artery angle, vessel diameter, and circumference. Results The median age for the total patient population ( n = 114) at baseline was 59.06 ± 10.40 years. Mean time interval between baseline magnetic resonance angiography and magnetic resonance angiography after 10 years of these patients was 129.18 ± 7.77 months. For the whole group, there was a significant increase in the bifurcation angle ( p < 0.05) over a 10-year period. A significant increase was also noted in the diameter and circumference of the common carotid artery ( p < 0.05). However, the other vessel diameters and circumferences (bulb carotid, internal carotid) as well as the internal carotid angle did not significantly change ( p ≥ 0.05). Conclusion The diameter and circumference of the common carotid artery and bifurcation angle significantly increased over a decade of life.