Fatigue crack propagation analysis of plaque rupture and thrombosis

To elucidate the mechanisms of these events, the atherosclerotic rabbit model provides a unique and powerful tool that. The pulsatile blood flow in the arteries generates mechanical stresses that affect the rupture of the atherosclerotic plaque. 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. Rupture of atheromatous plaque in the carotid artery often leads to thrombosis and subsequent stroke. The total fatigue life is the sum of crack initiation life and crack propagation life. Rupture of atheromatous plaque is the major cause of stroke or heart attack. Eroded plaques tend to lack features associated with rupture prone. Because the time and scope for intervention are limited, the key to reducing the high morbidity and mortality of these conditions is prevention. Venous thromboembolism vte, with an annual incidence of 1. 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. Incremental crack propagation was dynamically simulated based on. The former predispose plaques to rupture, whereas the latter may precipitate disruption if. Numerical investigation of atherosclerotic plaque rupture. Gianluca rigatelli, md, phd, ebir, 1 marco zuin, 2 tra t.

Plaque rupture definition of plaque rupture by medical. Mesoscopic fracture mechanism of mode ii delamination. Flammer, byoung joo choi, joerg herrmann, rajiv gulati, ryan j. Compared with metal whose fatigue behavior has been widely quantified, plaque is a more complex structure with various atherosclerotic components and anisotropic material properties. 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. Thus, fatiguecrackpropagation results are usually presented in terms of crack. Fatigue strength and fatigue fracture mechanism for spot. Individual product monographs should be consulted for important drug interactions prior to prescribing. Meeting a key functional requirement of nextgeneration medical devices. Fatigue crack initiation and propagation life prediction. In addition, plaque rupture and subsequent healing is recognized to be a major cause of further rapid plaque progression. Though a lot of fatigue models have been developed and used.

The correlation between fatigue crack propagation and stress intensity factor is analyzed. 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. Fourdimensional ultrasonographic characterization of. Fracture that occurs by rapid crack propagation and without appreciable macroscopic deformation. 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. 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. Stressrelaxation and cyclic behavior of human carotid plaque. Gross photograph and composition of plaque rupture. Intracoronary cavitation as a cause of plaque rupture and. Repeated episodes of thrombosis as a potential mechanism of plaque progression in cardiac allograft vasculopathy. If the thrombus breaks off and flows towards the lungs, it can become a pulmonary embolism pe, a blood clot in the lungs. Considering that the cardiovascular system is a classic fatigue environment, plaque rupture was treated as a chronic fatigue crack growth process in this study. 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.

The study comprised 93 vte patients and 102 healthy controls. 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. The separation of a lipidrich lesion from the wall of a blood vessel. Careful analysis of such ruptured culprit lesions has created the concept of vulnerable plaques. 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. Crack propagation fatigue crack crack initiation crack behavior fillet weldtjoint geometric parameters crack growth direction strain energy density hotrolled aisi 1035 fatigue strength the fatigue tests on tjoints, with and without toe undercut, were conducted to determine the actual crack growth path and to verify the analytical predictions. New insights into atherosclerotic plaque rupture postgraduate. Coronary plaque disruption circulation aha journals.

Plaque rupture plays a role in the majority of acute coronary syndromes. Rupture of atherosclerotic plaque with resulting thromboembolism is a predominant. The evidence of previous plaque rupture and intraplaque. A venous thrombus is a blood clot thrombus that forms within a vein. Vte constitutes a spectrum ranging from asymptomatic distal deep venous thrombosis dvt and subsegmental pulmonary embolism pe, to limb threatening dvt and fatal pe. 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. These devices can keep a vessel from rapidly closing after angioplasty if plaque rupture occurs. Fatigue crack propagation behavior and fracture surface. A metaanalysis of anticoagulation for calf deep venous.

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. 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. How does calcification influence plaque vulnerability. With this relevance, in vivo imagebased mechanical analysis has been employed. When one measures fatigue crack propagation rate, a crack increment, ha, and its corresponding increment in load cycles, an, are measured. 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. Increased understanding of thrombotic mechanisms together with the recent identification of subsets of patients who are at increased risk of. The nucleation phase typically represents the longest period of fatigue life, although local irregularities could significantly shorten the nucleation period. Crack propagation paths are sometimes prerequisite for the proper estimation of fatigue crack propagation, because curved crack paths and sharp crack turning could. Growth of coronary plaque presents clinically as angina when coronary flow is decreased. Fatigue analysis was performed based on the plaque geometry derived from in vivo mri of the carotid artery at the point of maximum stenosis.

We searched medline 1950october 2010, the cochrane library 1993october 2010, trial registries, meeting abstracts, and selected references, using no limits. Rupture of atherosclerotic plaque with resulting thromboembolism is a. Nguyen, 4 aravinda nanjundappa, 5 ernest talarico, 6 le cao phuong duy, 7 and thach nguyen 3, 8. These plaques typically cause only minor stenosis of the coronary lumen and are morphologically characterized by a. A common type of venous thrombosis is a deep vein thrombosis dvt, which is a blood clot in the deep veins of the leg.

Materials and methods 1mri acquisition twenty seven patients table 1 with atherosclerotic carotid artery disease were included in this study. Atherosclerotic plaque rupture is a catastrophic event that contributes to mortality and. Journal of biomechanical engineering, 510, article number. The crack growth rate under various stress ratios was well correlated to the stress. Mribased fatigue analysis predicts plaque vulnerability. Anticlotting agent helps reduce the incidence and impact. Stp1497 residual stress effects on fatigue and fracture. Microscopic analysis demonstrated structural damage in the fatigued. 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. A technique of fracture analysis used to determine the stress level at which preexisting cracks of known size will propagate leading to fracture. Fatiguecrack propagation is more complicated than fatigue because different life curves fig. Pdf stress analysis of fracture of atherosclerotic plaques. Fatigue life prediction has become important because of complex nature of fatigue as it is influenced by several factors, statistical nature of fatigue phenomena and time consuming fatigue tests. In such patients, treatment with pharmacomechanical, catheterdirected thrombus reduction therapy should be considered since it rapidly relieves venous obstruction with few adverse effects.

Propagated thrombus definition of propagated thrombus by. The addition of spectroscopic analysis supplements the structural detail of oct. 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. Paris law in fracture mechanics is adopted to determine the fatigue crack growth rate. Rupture, atherosclerotic plaque and fuel cells researchgate, the. Intravascular modalities for detection of vulnerable plaque. Stress analysis of fracture of atherosclerotic 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. Modified paris law was used to govern crack propagation and the. The genetic variants linked with the susceptibility of individuals to vte are well known. Investigations on the fatigue crack propagation threshold. From fatigue research it is known that fatigue life can often be divided into three periods. Gillard, impact of calcification and intraluminal thrombus. Persistent inflammation and mechanical injury associated with cholesterol crystal accretion within atherosclerotic plaques typically precedes plaque disruption rupture andor erosion and thrombosisoften the terminal events of atherosclerotic cardiovascular disease. Stress intensity factor analysis and fatigue behavior of a crack in the residual stress field of welding. 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. Lennon, soo jin kang, akiko maehara, hironori kitabata, takashi akasaka, lilach o lerman, sudhir s. Fatigue rupture analysis and the fatigue life were used to evaluate the rupture risk. Pharmacologic prevention of coronary plaque rupture the. Morphometric analysis of the composition of coronary arterial plaques in. 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.

Unstable plaque rupture and from a thrombus and partially or fully occlude artery and thus acs. Myocardial infarction contributes to most fatalities in which atherosclerotic plaque disruption is the underlying pathology. Effect of shot peening on fatigue crack growth in 7075t7351. In this study, we investigate the fatigue process in human carotid plaques using in vivo carotid magnetic resonance mr imaging. Fatigue analysis of welded joints for low and medium carbon steels is well established and documented in british standard, bs 7608. Part of the problem for fatigue and fatiguecrack propagation is that these behaviors are influenced by a wide range of parameters that include cyclic stress. Massive dvt is defined as iliofemoral thrombosis with severe symptoms. Fatigue crack propagation analysis of plaque rupture qut. Fatigue crack propagation analysis of plaque rupture. This is the immediate cause of acute myocardial infarction. Prediction of atherosclerotic plaque life perceptions. Fatigue cumulative damage and crack propagation analysis. Fatigue crack propagation must be caused by a shear andor a normal separation mode. 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.

Repeated episodes of thrombosis as a potential mechanism. Evolving concepts in the triad of atherosclerosis, inflammation and thrombosis. Prediction of short fatigue crack propagation on the base of nonlocal fracture criterion 47. Present study assesses mutations in six candidate genes contributing to the etiology of vte in indian subjects. The role of plaque rupture and thrombosis in coronary. The fatigue crack growth resistance of the interlayertoughened cfrp was higher than that of conventional cfepoxy. Analysis of stress intensity factor and crack propagation. 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. Ihdacs pathophysiology and treatment flashcards quizlet. Anticlotting agent helps reduce the incidence and impact of stent thrombosis during pci. Fatigue and plaque rupture in myocardial infarction. Mechanisms of plaque rupture cardiovascular research oxford. Morphological aspects of fatigue crack propagation part ii. Arteriosclerosis, thrombosis, and vascular biology, 37s1.

Plateletrich thrombus at the site of plaque rupture is characterized as white granular. Editorial by vandenbroucke venous thrombosis and venous thromboembolism are major medical problems. Sudden thrombus growth on previously disrupted or intact plaques due to. Modified clot waveform analysis to measure plasma coagulation potential in the presence of the anti. Crack propagation, fracture surface analysis, retardation, twostep loading, striation, crack closure phenomena. A crack modeled on the pressure vessel and then the stress intensity factor for crack propagation in different methods is evaluated. Plaque fatigue crack growth per pressure pulse was estimated using an adapted parisrelation. 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. Mesoscopic fracture mechanism of mode ii delamination fatigue crack propagation in interlayertoughened cfrp.