Cap buckling as a potential mechanism of atherosclerotic plaque vulnerability.
Plaque rupture in atherosclerosis is the primary cause of potentially deadly coronary events, yet about 40% of ruptures occur away from the plaque cap shoulders and cannot be fully explained with the current biomechanical theories. Here, cap buckling is considered as a potential destabilizing factor which increases the propensity of the atherosclerotic plaque to rupture and which may also explain plaque failure away from the cap shoulders. To investigate this phenomenon, quasistatic 2D finite element simulations are performed, considering the salient geometrical and nonlinear material properties of diverse atherosclerotic plaques over the range of physiological loads. The numerical results indicate that buckling may displace the location of the peak von Mises stresses in the deflected caps. Plaque buckling, together with its deleterious effects is further observed experimentally in plaque caps using a physical model of deformable mock coronary arteries with fibroatheroma. Moreover, an analytical approach combining quasistatic equilibrium equations with the Navier-Bresse formulas is used to demonstrate the buckling potential of a simplified arched slender cap under intraluminal pressure and supported by foundations. This analysis shows that plaque caps - calcified, fibrotic or cellular - may buckle in specific undulated shapes once submitted to critical loads. Finally, a preliminary analysis of intravascular ultrasonography recordings of patients with atherosclerotic coronary arteries corroborates the numerical, experimental and theoretical findings and shows that various plaque caps buckle in vivo. By displacing the sites of high stresses in the plaque cap, buckling may explain the atherosclerotic plaque cap rupture at various locations, including cap shoulders.
Montreal Heart Institute, 5000 Belanger Street, Montreal, Canada H1T 1C8; Université de Montréal, Pavillon Roger-Gaudry, 2900 boul. Edouard-Montpetit, Montreal, Canada H3T 1J4.
Maria
M
Abdelali
Montreal Heart Institute, 5000 Belanger Street, Montreal, Canada H1T 1C8; McGill University, MacDonald Building, 817 Sherbrooke Street West, Montreal, Canada H3A 0C3.
Steven
S
Reiter
Montreal Heart Institute, 5000 Belanger Street, Montreal, Canada H1T 1C8; McGill University, MacDonald Building, 817 Sherbrooke Street West, Montreal, Canada H3A 0C3.
Rosaire
R
Mongrain
Laboratoire d'Imagerie Médicale, École Polytechnique de Montréal, 2900 boul. Edouard-Montpetit, Montreal, Canada H3T 1J4.
Michel
M
Bertrand
Montreal Heart Institute, 5000 Belanger Street, Montreal, Canada H1T 1C8; Université de Montréal, Pavillon Roger-Gaudry, 2900 boul. Edouard-Montpetit, Montreal, Canada H3T 1J4.
Philippe L
PL
L'Allier
Montreal Heart Institute, 5000 Belanger Street, Montreal, Canada H1T 1C8.
Ekaterini A
EA
Kritikou
Montreal Heart Institute, 5000 Belanger Street, Montreal, Canada H1T 1C8; Université de Montréal, Pavillon Roger-Gaudry, 2900 boul. Edouard-Montpetit, Montreal, Canada H3T 1J4. Electronic address: jean-claude.tardif@icm-mhi.org.
Jean-Claude
JC
Tardif
D001696:Biomechanical Phenomena; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000293:injuries; D006801:Humans; D008422:Materials Testing; D055595:Mechanical Phenomena; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging; D011312:Pressure; D012421:Rupture; D013314:Stress, Mechanical; D014463:Ultrasonography
Atherosclerosis; Buckling instability; Delamination; Elasticity; Finite element analysis; Plaque vulnerability