Pdf stress analysis of fracture of atherosclerotic plaques. Flammer, byoung joo choi, joerg herrmann, rajiv gulati, ryan j. Sudden thrombus growth on previously disrupted or intact plaques due to. In addition, plaque rupture and subsequent healing is recognized to be a major cause of further rapid plaque progression. Careful analysis of such ruptured culprit lesions has created the concept of vulnerable plaques. Coronary plaque disruption circulation aha journals. From the mechanics view point, the pulsatile blood flow in the arteries resembles a fatigue environment and generates stresses that affect the rupture of the atherosclerotic plaque. Unstable plaque rupture and from a thrombus and partially or fully occlude artery and thus acs. We searched medline 1950october 2010, the cochrane library 1993october 2010, trial registries, meeting abstracts, and selected references, using no limits.
Repeated episodes of thrombosis as a potential mechanism. A venous thrombus is a blood clot thrombus that forms within a vein. Lennon, soo jin kang, akiko maehara, hironori kitabata, takashi akasaka, lilach o lerman, sudhir s. The former predispose plaques to rupture, whereas the latter may precipitate disruption if. Microscopic analysis demonstrated structural damage in the fatigued. Effect of shot peening on fatigue crack growth in 7075t7351. The pulsatile blood flow in the arteries generates mechanical stresses that affect the rupture of the atherosclerotic plaque. Fatigue crack propagation analysis of plaque rupture qut. Fatigue crack propagation analysis of plaque rupture. Finite element analysis calculates stress intensity factor in the values of the jintegral are based on the stress intensity factors, jk, and by evaluating the contour integral directly, ja. Because the time and scope for intervention are limited, the key to reducing the high morbidity and mortality of these conditions is prevention. The mechanism of plaque rupture is not entirely clear but is thought to be a multifactorial process involving thinning and weakening of the fibrous cap and biomechanical stress as the trigger leading to plaque rupture. Investigations on the fatigue crack propagation threshold.
In a recent study in which careful quantitative coronary angiography was performed on patients with acs, the vast majority were found to have significant stenosis underneath their thrombus. If the thrombus breaks off and flows towards the lungs, it can become a pulmonary embolism pe, a blood clot in the lungs. A technique of fracture analysis used to determine the stress level at which preexisting cracks of known size will propagate leading to fracture. Though a lot of fatigue models have been developed and used. Materials and methods 1mri acquisition twenty seven patients table 1 with atherosclerotic carotid artery disease were included in this study. The genetic variants linked with the susceptibility of individuals to vte are well known. For fatigue, fatiguecrack propagation, and fracture data, however, design allowable values are usually not available and the data are presented in terms of typical or average values. Present study assesses mutations in six candidate genes contributing to the etiology of vte in indian subjects. The nucleation phase typically represents the longest period of fatigue life, although local irregularities could significantly shorten the nucleation period. Plaque fatigue crack growth per pressure pulse was estimated using an adapted parisrelation. Stressrelaxation and cyclic behavior of human carotid plaque. Ro, dauskardt, rh, yu, w, brendzel, am 1990 cyclic fatiguecrack propagation, stresscorrosion, and fracturetoughness behavior in pyrolytic carbon. Paris law in fracture mechanics is adopted to determine the fatigue crack growth rate. Mesoscopic fracture mechanism of mode ii delamination fatigue crack propagation in interlayertoughened cfrp.
Morphological aspects of fatigue crack propagation part ii. To elucidate the mechanisms of these events, the atherosclerotic rabbit model provides a unique and powerful tool that. Prediction of short fatigue crack propagation on the base of nonlocal fracture criterion 47. In this study, we explore the fatigue process in human carotid artery plaques using in vivo highresolution mr imaging by assessing the propagation of cracks leading to plaque rupture. Compared with metal whose fatigue behavior has been widely quantified, plaque is a more complex structure with various atherosclerotic components and anisotropic material properties. Fracture mechanics theory was introduced to describe the stress status at the crack tip and paris law was used to calculate the crack growth rate.
Fatigue and plaque rupture in myocardial infarction. Considering that the cardiovascular system is a classic fatigue environment, plaque rupture was treated as a chronic fatigue crack growth process in this study. Thermal residual stress relaxation in powder metal in100 superalloy. The correlation between fatigue crack propagation and stress intensity factor is analyzed. Rupture of atheromatous plaque in the carotid artery often leads to thrombosis and subsequent stroke. A crack modeled on the pressure vessel and then the stress intensity factor for crack propagation in different methods is evaluated. It is suggested that crack propagation analysis can lead to a better recognition of factors involved in plaque rupture and more accurate determination of vulnerable plaques. However, this current fatigue design code does not cover high strength steel structures, particularly, weldments of armor steel plates with austenitic stainless steel weid metal.
Pharmacologic prevention of coronary plaque rupture the. Plaque rupture definition of plaque rupture by medical. This is the immediate cause of acute myocardial infarction. From fatigue research it is known that fatigue life can often be divided into three periods. Fracture that occurs by rapid crack propagation and without appreciable macroscopic deformation. Analysis of fatigue crack propagation behavior in fillet. The most majority part of the fatigue crack growth at the spot weld and its propagation to the surface of a specimen which cannot to observed.
Anticlotting agent helps reduce the incidence and impact. Fatigue analysis was performed based on the plaque geometry derived from in vivo mri of the carotid artery at the point of maximum stenosis. In this study, we used a fatigue analysis based on in vivo magnetic resonance imaging mri to investigate the rupture initiation location, crack propagation path and fatigue life within plaques of asymptomatic and symptomatic individuals. Rupture, atherosclerotic plaque and fuel cells researchgate, the. Mesoscopic fracture mechanism of mode ii delamination. Gross photograph and composition of plaque rupture. Fatigue crack initiation and propagation life prediction. Stress intensity factor analysis and fatigue behavior of a crack in the residual stress field of welding. Plaque rupture plays a role in the majority of acute coronary syndromes.
The study comprised 93 vte patients and 102 healthy controls. Analysis of stress intensity factor and crack propagation. The evidence of previous plaque rupture and intraplaque. New insights into atherosclerotic plaque rupture postgraduate. Incremental crack propagation was dynamically simulated based on. Fatigue strength and fatigue fracture mechanism for spot. Fourdimensional ultrasonographic characterization of. Propagated thrombus definition of propagated thrombus by. Morphometric analysis of the composition of coronary arterial plaques in. Rupture of atheromatous plaque is the major cause of stroke or heart attack. Rupture of atherosclerotic plaque with resulting thromboembolism is a predominant.
Increased understanding of thrombotic mechanisms together with the recent identification of subsets of patients who are at increased risk of. Crack propagation, fracture surface analysis, retardation, twostep loading, striation, crack closure phenomena. The fatigue crack growth resistance of the interlayertoughened cfrp was higher than that of conventional cfepoxy. Eroded plaques tend to lack features associated with rupture prone. Stp1497 residual stress effects on fatigue and fracture. Growth of coronary plaque presents clinically as angina when coronary flow is decreased. The separation of a lipidrich lesion from the wall of a blood vessel. The process of atherosclerotic plaque rupture with superimposed thrombosis is generally considered to play an integral role in acute coronary events and depends more on features of plaque vulnerability than on the degree of stenosis. Repeated episodes of thrombosis as a potential mechanism of plaque progression in cardiac allograft vasculopathy. Thus, fatiguecrackpropagation results are usually presented in terms of crack. In the present work here, the fatigue crack propagation threshold of a surface crack for an armco iron loaded in the vhcf regime was investigated by a new approach which combines the fracture surface analysis and the temperature recording on the surface during the test by an infrared camera.
Mribased fatigue analysis predicts plaque vulnerability. Mechanical properties, tensile testing, thrombosis, rupture, aneurysms, finite element analysis, stress, aorta, biological tissues, maintenance regionspecific medial fiber microarchitecture in the longitudinalradial and circumferentialradial planes of ascending thoracic aortic aneurysm among bicuspid and tricuspid aortic. How does calcification influence plaque vulnerability. However, it is rupture of the plaque that causes the catastrophic. Crack propagation paths are sometimes prerequisite for the proper estimation of fatigue crack propagation, because curved crack paths and sharp crack turning could. Fatigue failure being the accumulation of the damage due to repeated loading that occurs when the stresses are much lower than those needed to rupture the plaque with normal loading.
These devices can keep a vessel from rapidly closing after angioplasty if plaque rupture occurs. Prediction of atherosclerotic plaque life perceptions. In order to maintain structural integrity of welded structures, it is of great importance to evaluate the fitness for serviceability of the structural components, in which fatigue cracks are found during inservice inspections. Individual product monographs should be consulted for important drug interactions prior to prescribing. Intravascular octbased management in plaque erosion the erosion study ikkyung jang, md, phd harvard medical school massachusetts general hospital in collaboration with bo yu, md, phd harbin medical university. The total fatigue life is the sum of crack initiation life and crack propagation life. Stress analysis of fracture of atherosclerotic plaques. Fatigue crack propagation must be caused by a shear andor a normal separation mode. Massive dvt is defined as iliofemoral thrombosis with severe symptoms. Gross photograph of a coronary artery cut in crosssection showing the site of a plaque rupture arrow with an underlying necrotic core nc and luminal thrombus th. The addition of spectroscopic analysis supplements the structural detail of oct. Fatigue rupture analysis and the fatigue life were used to evaluate the rupture risk. The damage this does to the lining of a blood vessel triggers a cascade of events that result in blood clot formation within the vessel and its eventual obstruction. Fatiguecrack propagation is more complicated than fatigue because different life curves fig.
When one measures fatigue crack propagation rate, a crack increment, ha, and its corresponding increment in load cycles, an, are measured. Plateletrich thrombus at the site of plaque rupture is characterized as white granular. Thrombosis is a term for a blood clot occurring inside a blood vessel. In such patients, treatment with pharmacomechanical, catheterdirected thrombus reduction therapy should be considered since it rapidly relieves venous obstruction with few adverse effects. A common type of venous thrombosis is a deep vein thrombosis dvt, which is a blood clot in the deep veins of the leg. Anticlotting agent helps reduce the incidence and impact of stent thrombosis during pci. Fatigue analysis of welded joints for low and medium carbon steels is well established and documented in british standard, bs 7608.
Vte constitutes a spectrum ranging from asymptomatic distal deep venous thrombosis dvt and subsegmental pulmonary embolism pe, to limb threatening dvt and fatal pe. Intravascular modalities for detection of vulnerable plaque. Mechanisms of plaque rupture cardiovascular research oxford. Full text pdf 1219k abstracts references10 as a retardation of fatigue crack propagation occurs under two step loading such as high to low loading, it is difficult to estimate the fatigue life in variable loading. A metaanalysis of anticoagulation for calf deep venous. Atherosclerotic plaque is subjected to a repetitive deformation due to arterial pulsatility during each cardiac cycle and damage may be accumulated over a time period causing fibrous cap fc fatigue, which may ultimately lead to rupture. With this relevance, in vivo imagebased mechanical analysis has been employed. In this study, we investigate the fatigue process in human carotid plaques using in vivo carotid magnetic resonance mr imaging. Fatigue crack propagation behavior and fracture surface. Gianluca rigatelli, md, phd, ebir, 1 marco zuin, 2 tra t. Rupture of atherosclerotic plaque with resulting thromboembolism is a. Ihdacs pathophysiology and treatment flashcards quizlet. The crack growth rate under various stress ratios was well correlated to the stress. These plaques typically cause only minor stenosis of the coronary lumen and are morphologically characterized by a.
Editorial by vandenbroucke venous thrombosis and venous thromboembolism are major medical problems. Gillard, impact of calcification and intraluminal thrombus. Journal of biomechanical engineering, 510, article number. Intracoronary cavitation as a cause of plaque rupture and.
It is suggested that crack propagation analysis can lead to a better recognition of factors involved in plaque rupture and more. Fatigue cumulative damage and crack propagation analysis. Nguyen, 4 aravinda nanjundappa, 5 ernest talarico, 6 le cao phuong duy, 7 and thach nguyen 3, 8. Venous thromboembolism vte, with an annual incidence of 1. Myocardial infarction contributes to most fatalities in which atherosclerotic plaque disruption is the underlying pathology. Arteriosclerosis, thrombosis, and vascular biology, 37s1. The role of plaque rupture and thrombosis in coronary.
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