PAD occurs when atherosclerosis is found in arteries that perfuse the limbs, particularly the lower extremities. Atherosclerosis is thickening and hardening of the vessel wall caused by an accumulation of lipid-laden macrophages inside the arterial wall, which causes the formation of lesions or plaques. This process begins when the endothelial cells that line the artery walls are damaged. This lesion progresses from endothelial injury and dysfunction to fatty streaks to fibrotic plaques and ending in a complete lesions. Endothelial damage can be caused by a variety of factors including; smoking hypertension, diabetes, increased levels of low-density lipoprotein (LDL) and high-density lipoprotein (HDL), and autoimmunity. Atherosclerosis …show more content…
These inflamed cells are unable to make the normal amounts of antithrombic and vasodilating cytokines. Adhesion molecules that bind macrophages and other inflammatory and immune cells are expressed by inflamed endothelial cells. Many inflammatory cytokines and enzymes are released when macrophages adhere to the injured endothelium, which cause further injury to the vessel wall. The inflammation process creates toxic oxygen radical that cause oxidation of the LDL that have built up in the vessel intima. When LDL is oxidized it promotes added adhesion molecule expression with the recruitment of monocytes that differentiate into macrophages that will consume oxidized LDL when they infiltrate into the tunic intima. A lesion is then formed when the lipid-laden macrophages (foam cells) build up in large amounts. These lesions, also called fatty streaks, are found on the arterial walls of most people and is what defines the second step of atherosclerosis. Fatty streaks create more toxic oxygen radicals, recruit T cells that lead to autoimmunity, and release additional inflammatory mediators that will cause increased damage to the arterial
Margination and adhesion to the endothelium, in which accumulation of leukocytes occurs along the endothelial wall for adhesion. Afterward, these adhesions cause the separation of endothelial cells, allowing the leukocytes to extend and Transmigrate through the vessel walls. Followed by the response of chemical mediators(chemotaxis) that influence cell migration via an energy directed process which triggers the activation of Phagocytosis, in which monocytes, neutrophils, and tissue macrophages are activated to engulf and degrade cellular debris and
Myocardial infarctions are caused by vascular endothelial disruption most often associated with plaque build-up or atherosclerosis that develops over several years and causes thrombus formation which in turn
An artery is an elastic blood vessel that transports blood away from the heart. There are two main types of arteries: pulmonary arteries and systemic arteries.
Atherothrombosis is the pathophysiologic hallmark of acute coronary syndrome which can lead to an acute myocardial infarction. Platelet aggregation is one of the major reasons why ACS occurs, arterial plaque builds up over time from products such as lipids, cholesterol and fibrin. The vasa vasorum
Coronary artery disease (CAD) is the most common type of multifactorial chronic heart disease. It is a consequence of plaque buildup in coronary arteries. The arterial blood vessels, which begin out smooth and elastic become narrow and rigid, curtailing blood flow resulting in deprived of oxygen and nutrients to the heart [1].
The preliminary step in myocardial infarction is atherosclerosis. Atherosclerosis does not occur abruptly, it is a gradual and dynamic inflammatory disease which causes the narrowing of lumen due to the deposition of lipid and foam cells. The formation of fatty streak; which will eventually become a plaque causes the vessel lumen to diminish. The plaque will become unstable, rupture and eventually lead to the event of plaque disruption.
In conclusion, endothelial cells in atherosclerosis causes the increased expression of surface adhesion molecules which results in the increased amount of leukocytes attracted to the site and thus causing more inflammation than usual. In infective endocarditis, NBTE allows bacterial adhesion of the heart valves, mediated by ClfA and then FnbpA. These causes a range of reactions spanning of vegetative growth to inflammation.
Coronary heart disease is defined by the hardening of the epicardial coronary arteries. The buildup of plaque in the arteries slowly narrows the coronary artery lumen. In order to better understand the physiology of the disease, it is important to first know the basic anatomy of the human heart. The aorta, located in the superior region of the heart, branches off into two main coronary blood vessels, otherwise known as arteries. The arteries are located on the left and right side of the heart and span its surface. They subsequently branch off into smaller arteries which supply oxygen-rich blood to the entire heart (Texas Heart Institute, 2013). Therefore, the narrowing of these arteries due to plaque buildup significantly impairs blood flow throughout the heart.
Peripheral artery disease is usually caused by atherosclerosis, which is when fatty deposits accumulate in the arteries of, most likely, limbs. This does affect all arteries throughout the body, then in turn, slowing the blood flow. PAD may also be due to inflammation of the blood vessels, injury to the extremities, or even exposure to radiation. “Peripheral arterial disease (PAD) affects approximately 10% of the American population” (Gurbir Dhaliwal; Peripheral arterial disease: Epidemiology, natural history, diagnosis and treatment; 2007). If not taken care of, PAD may lead to critical limb ischemia, open sores on the feet or legs that become infected by gangrene. The gangrene is then removed surgically, but doctors might have to amputate the extremity all together. Another issue that arises with PAD if it is not under control is the risk of stroke or heart attack. These can cause death to part of the heart or brain, or even death itself. The population more at risk would be smokers, diabetics, people who are obese, those with hypertension or hyperlipidemia, over the age of 50, have a family history of PAD, or those with a high level of homocysteine. If someone does fall into a few of these categories a physician can do a few tests to check for PAD. The doctor will more than likely start off with a physical exam, blood test, and possibly an ultrasound. From there the physician may try an ankle-brachial index, or ABI, which compares the blood pressure of the feet to the blood pressure of the arm. “An American survey of 2174 patients older than 40 years of age used the ankle-brachial index (ABI) as a screening tool, and showed a PAD prevalence of 0.9% between the ages of 40 and 49 years, 2.5% between the ages of 50 and 59 years, ...
Atherosclerosis is the most common cause of CAD. Atherosclerosis is a progressive disease characterized by fat deposits in the arteries causing them to block the normal passage of blood. No one is quite sure how atherosclerosis develops. The plaque consists mostly of cholesterol, phospholipids and smooth muscle cells. They also reduce the size of the lumen of the affected artery which impairs the blood flow of this artery and later on could form a thrombus that will completely occlude the vessel. “Unfortunately, signs and symptoms of atherosclerosis usually don’t develop until at least 70% of an artery’s lumen has become obstructed. Angina is almost always the first symptom to appear.”(Journal: The killer behind CAD,2010). Modifiable factors that could prevent the occurrence of CAD include cigarette smoking, obesity, physical inactivity, atherogenic diet like diet high in cholesterol, use of contraceptive and hormone therapy replacement. “Women continue to ...
What is coronary heart disease (CHD)? It is a disease when plaque gets built up in the coronary arteries; and the job of the arteries are to provide rich-oxygenated blood to the heart muscle. Built plaque in the arteries leads to atherosclerosis and the plaque that is built can result from over the years. Throughout the years, the plaque tends to get hard or can rupture. If hardened, the arteries are now narrow and have weakened the flow of blood that travels to the heart. Blood clots can form from the plaque rupturing which can cause a great chance for the blood flow to be mostly blocked or blocked altogether. There are other names for coronary heart disease such as coronary artery disease, atherosclerosis, ischemic heart disease, etc.
Atherosclerosis begins when the inner wall of the artery becomes damaged and cholesterol and fatty plaques begin to lodge in the arteries. Damage to the endothelial wall inside the artery can be caused by hypertension, hyperlipidemia, and hyperglycemia (“Subclinical Atherosclerosis..” 443). When this happens, the immune system responds by sending monocytes to the damaged area. The monocytes turn into macrophages; their job is to eat up the excess cholesterol and unblock the artery. The macrophages are unable to digest all of the cholesterol, and as a result turn in to foam cells. When many macrophages are turned into foam cells, plaque results, and protrudes into the arterial wall, restricting blood flow and raising blood pressure (“Atherosclerosis Growth Process.” 8). If the plaque becomes too large it may break, releasing plaque into the blood. This can cause a great reduction in blood flow or a clot, resulting in stroke or myocardial infarction (“Stroke Risk.” 3).
The arteries supply blood rich in oxygen to the body, the veins direct deoxygenated blood from the capillaries back to the heart. These roles make up the circulatory function. Blood flow through these blood vessels can be disrupted resulting in peripheral vascular diseases. These diseases occur as a result of narrowing or blocking of the blood vessels. The risk factors of peripheral vascular diseases include diabetes, smoking, high level of cholesterol, overweight, high blood pressure etc. these risk factors result to aneurysms, Raynaud’s diseases, Buerger’s disease, renal artery disease etc. With this diseases, the peripheral vascular system should be assessed to enable nurses and other health personnel make good
Etiology Myocardial infarction occurs when the coronary arteries are blocked by a blood clot. It is commonly known as a “heart attack”. The heart needs its own constant supply of oxygen and nutrients to work properly. Two coronary arteries deliver oxygenated blood to the heart, and if one of these two arteries fails or becomes blocked, then a portion of the heart will not acquire the necessary oxygen. This clot could be because of CAD (coronary artery disease), which happens when the inner walls of the coronary arteries thicken because of buildup of cholesterol, fatty deposits, calcium among other elements that are carried in the blood (Boston Scientific, 2009).
Inflammation which is part of the innate immune system is a process by which the body reacts to injury protecting it from infection and foreign substances with the help of the body’s white blood cells “Inflammation can be defined as the body’s local vascular and cellular response to injury caused by factors that invade and injure the body from the outside (exogenous factors) or factors within the body that result in cellular or tissue injury (endogenous) factors” (Battle, 2009, P 238). Factors such as bacteria, viruses, burns, frostbite, chemical irritants, immune reactions and physical injury are examples of factors that can cause inflammation through different mechanisms. It is a protective mechanism with rapid response that neutralizes or destroys agents that causes injury and creates a barrier that limit the injury and prevents its spread to normal tissues (Battle, 2009). Also, it has elements that removes debris and heals the wound generated by the injury. It can be divided into acute and chronic inflammation.