File Name: asymptomatic atherosclerosis pathophysiology detection and treatment .zip
Anastasios Chatzikonstantinou, Marc E.
Abstract Atherosclerotic cardiovascular disease resulting in a heart attack is a major cause of morbidity and mortality, claiming millions of lives every year and killing more people than all wars combined. Both coronary calcium scoring and carotid intima thickness are approved imaging tests for further stratifying risk in the intermediate-risk patient. Clinicians can stratify individual risk more precisely using these imaging technologies, allowing for more targeted approaches to treatment.
However, cardiovascular disease still takes the lives of more than 2, Americans each day, an average of 1 death every 40 seconds, 2 and it is still the No.
One reason heart attacks and stroke are still so prevalent is due to the lack of preventive cardiology training given to healthcare providers worldwide ie, lack of investment. Preventive cardiology may be described as the aggressive early detection and treatment of cardiovascular conditions such as coronary artery disease and hypertension.
Since most atherosclerosis is asymptomatic, imaging allows us to detect it in early, preclinical stages, allowing for early intervention. The purpose of this article is to review the imaging that is most clinically useful to the practitioner, providing scientific support and rationale for its use. Only imaging technologies that are the most clinically useful will be addressed. The problem: The current standard of care does not include detection of asymptomatic atherosclerosis.
Instead, traditional risk factors are evaluated, the patient is put into a low-, medium-, or high-risk category, and lipid targets are determined by the clinician depending on the category.
Thus, coronary artery disease is not detected early. We know that early detection of cancer saves lives. The same is true for atherosclerosis. A one-size-fits-all approach based only on guidelines leaves some patients over-treated and others painfully under-treated. This study confirmed prior suspicions suggesting poor prediction using traditional risk factors in particular lipids , thus highlighting the shortcomings of existing national cholesterol education program guidelines.
There are many risk factors. The issue of what to do about high cholesterol is a daily issue for most practitioners. Does the patient have atherosclerosis or just high cholesterol? What should the treatment be? Does the patient have the type of plaque that could rupture? What is the real year risk of having a coronary event for the patient sitting in front of you? The national lipid association uses f categories. Most practitioners use the online calculator. Only an image can do that.
Traditional risk factors do a poor job of determining risk, especially for those in the intermediate risk range. Traditional risk factors may identify persons at very low or very high risk of heart attack or stroke in the next 10 years, but the majority of the population belongs to an intermediate-risk group for which the predictive power of risk factors is low. Are you over-treating or under-treating a particular patient?
In the case of under-treatment, take the example of a year-old non-hypertensive male who is sedentary, slightly overweight, and has a first degree relative who had a heart attack before age His systolic blood pressure is , total cholesterol is , triglycerides are , and HDL is One reason heart attacks and stroke are still so prevalent is due to the lack of preventive cardiology training given to healthcare providers worldwide. Now, this patient tells you he had a heart scan last week and that he has plaque in multiple coronary arteries.
He is in the 80th percentile for his age and gender for coronary artery calcium calcium scoring. His calcium volume is He is now in a high-risk category because he has been found to have CAD in addition to his other risk factors. Who has a greater risk of a heart attack based on risk factors alone? Teenagers have been found to have type 1. Autopsies of young recruits during the Korean War showed fatty streaks, and unfortunately, much younger children today with metabolic syndrome also have demonstrated this.
Types IV and higher can rupture, potentially causing a myocardial infarction. The lesions in this illustration do not limit circulation, may not cause symptoms, and could be missed by an angiogram or treadmill test. The only way to actually see plaque is with an image. A heart scan, angiogram, computed tomography CT angiogram, cardiac magnetic resonance imaging MRI , carotid Doppler ultrasound, carotid intima-media thickness CIMT ultrasound, or intravascular ultrasound are all valid imaging technologies.
CT angiograms, cardiac MRI and intravascular ultrasound, while valid, are not as widely available, are more invasive, and are less likely to be covered by insurance. So in the interest of time and clinical utility, they will not be discussed here. Angiogram: This is the most common and most widely available test for the diagnosis coronary artery stenosis.
Although an angiogram is good for diagnosing a stenotic artery, it does not detect the earlier stages of plaque. Remember too that most heart attacks are from plaque rupture, not stenosis. Angiograms are appropriate for patients with angina or patients with a high and above coronary artery calcium score because a narrowed artery can cause blood flow limitation, and subsequent pain and heavy plaque burden increases the chance of the patient having a stenotic artery. There is no occlusion, so the angiogram should be negative.
This artery may contain vulnerable plaque that could rupture, causing a serious myocardial infarction. Weakness: Angiogram will not diagnose those with vulnerable plaque only and no blood flow limitation.
The vast majority of all heart attacks are the result of vulnerable plaque ruptures at sites in the artery with minor stenosis and no blood flow limitation. Exercise tolerance testing also known as exercise testing, stress testing, exercise stress testing, or treadmill testing is used to evaluate patients who have chest pain or chest pain on exertion, sometimes as part of an expanded physical, and patients with known coronary artery disease.
Treadmill tests are designed to monitor the electrical activity of the heart during exercise using the standardized Bruce protocol. ST segment depression horizontal or downsloping is the most reliable indicator of exercise-induced ischemia. In an older high-risk patient, such as those aged over 50 with chest pain, a negative result cannot rule out significant CAD. Exercise testing is therefore of greatest diagnostic value in patients with an intermediate risk of CAD. Adding to the problem is the fact that some patients will form coronary collateral circulation, allowing for adequate myocardial perfusion even though there may be an occluded artery.
With collateral circulation, new anastomoses form as an adaptation to myocardial hypoxia. This is common in individuals who have exercised vigorously for many years.
This type of patient may have a normal stress test but extensive plaque. Thus, a high-risk patient with vulnerable plaque may be told he passed his treadmill test but may die of a heart attack the next day from a plaque rupture.
Coronary collateral circulation has been recognized for a long time as an alternative source of blood supply to a myocardial area affected by ischemia. Treadmill testing and angiography do not detect early atherosclerosis well, as discussed previously. Intima-media thickening represents as seen by B-mode ultrasound is the earliest visible change we can see in the arterial wall and is a reliable, safe, and relatively inexpensive means of assessing asymptomatic atherosclerosis. Increased intimal-medial thickness IMT of the common carotid artery as assessed by B-mode ultrasonography is an index of atherosclerosis and is associated with symptomatic CAD.
Both ultrasound and autopsy studies have found that carotid atherosclerosis correlates well with atherosclerosis elsewhere in the circulation and can be used as a marker of general atherosclerosis. In healthy adults, CIMT ranges from 0. Normal values based on age and gender for black and white races have been established.
Faster velocity indicates stenosis by virtue of a narrowing of the artery. Unfortunately, in the early stages of plaque formation, there is little narrowing.
Thus, a standard carotid Doppler will not identify subtle thickening of the arterial wall and may miss subclinical atherosclerosis and the opportunity to begin treatment early, potentially mitigating the need for a surgical procedure down the road. Since the s, many statin drug trials have used CIMT for evaluating the regression and progression of atherosclerosis. CIMT is more accurate in predicting heart attack and stroke than any other risk factor alone, 29 and increased CIMT is an independent risk factor even in the absence of any other risk factors.
Newer machines are automated and reduce inter-operator variability significantly. These machines can be operated in a family practice or other point-of-care setting and reduce the need for outsourcing. May miss coronary artery disease if this is the only test conducted. A low IMT does not preclude the presence of cardiac vessel disease. Lack of agreed upon reference set of measurements normative data and cut-off points. Some lack of standardization on where IMT should be measured. Not covered by most insurance companies.
Strengths: CIMT ultrasounds may be valuable for patients who are considered to be at intermediate-risk for CHD, as test results can be used to reclassify patients into a higher or lower risk status based on the results of these tests.
Reclassification of patients as higher risk using CIMT allows earlier treatment, thus potentially reducing the future need for surgery and reducing risk of heart attack and stroke, saving money on the back end. Patients reclassified as lower risk need less intervention, saving money on the front end. Cardiac CT is a reliable and repeatable means of estimating coronary artery plaque burden.
EBT uses a low-radiation, high-speed electron beam to scan the heart noninvasively for the presence of calcium deposits. EBT is capable of very rapid imaging of cardiac anatomy. Between and the late s, hundreds of papers were published from around the world validating the cardiac application of EBT. However, MDCT imaging involves considerably more radiation exposure, and this should be taken into consideration when choosing which coronary artery calcification CAC procedure to recommend.
Both types of heart scans identify calcified plaque and give a direct indication of coronary plaque burden. CAC also can be used to track progression or regression of plaque.
This is particularly useful for clinicians when evaluating efficacy of treatment. EBT uses a rotating electron beam to acquire 64 slice, ms x-ray images at 3 mm intervals during second breath-hold. Any cardiac scan using less than 64 slice technology is not accurate enough.
CAC provides a useful estimate of total coronary plaque burden. The process of CAC involves osteoblast-like cells, cytokines, transcription factors, and bone morphogenic proteins. Francis heart study, individuals with an initial CAC score in the — range had a fold increase in relative risk compared to those with a zero score.
A CAC score of is generally thought to be the dividing line between mild and moderate atherosclerosis. Newer plaque has less calcium and is more prone to rupture than older calcified plaque, so both calcium burden and extent of disease progression should be taken into account.
Coronary artery disease
Coronary artery disease CAD , also called coronary heart disease CHD , ischemic heart disease IHD ,  or simply heart disease , involves the reduction of blood flow to the heart muscle due to build-up of plaque atherosclerosis in the arteries of the heart. Usually symptoms occur with exercise or emotional stress , last less than a few minutes, and improve with rest. Risk factors include high blood pressure , smoking , diabetes , lack of exercise, obesity , high blood cholesterol , poor diet, depression , and excessive alcohol. Ways to reduce CAD risk include eating a healthy diet , regularly exercising, maintaining a healthy weight, and not smoking. In , CAD affected million people and resulted in 8.
Abstract Atherosclerotic cardiovascular disease resulting in a heart attack is a major cause of morbidity and mortality, claiming millions of lives every year and killing more people than all wars combined. Both coronary calcium scoring and carotid intima thickness are approved imaging tests for further stratifying risk in the intermediate-risk patient. Clinicians can stratify individual risk more precisely using these imaging technologies, allowing for more targeted approaches to treatment. However, cardiovascular disease still takes the lives of more than 2, Americans each day, an average of 1 death every 40 seconds, 2 and it is still the No. One reason heart attacks and stroke are still so prevalent is due to the lack of preventive cardiology training given to healthcare providers worldwide ie, lack of investment. Preventive cardiology may be described as the aggressive early detection and treatment of cardiovascular conditions such as coronary artery disease and hypertension.
David E. Atherosclerotic plaque rupture and resulting intracoronary thrombosis are thought to account for most acute coronary syndromes. In addition, many cases of sudden cardiac death may be attributable to atherosclerotic plaque disruption and its immediate complications. Our understanding of the atherosclerotic process and the pathophysiology of plaque disruption has advanced remarkably. Despite these advances, event rates after acute coronary syndromes remain unacceptably high. This review will focus on the pathophysiology underlying atherosclerotic plaque development, the sequellae of coronary plaque rupture, and current therapies designed to treat the acute coronary syndromes.
Coronary artery disease
Recent cardiovascular clinical trials have also shed more light upon the efficacy and safety of novel compounds targeting the main pathways of atherosclerosis and its cardiovascular complications. The focus of this update is on the pathophysiology and medical interventions of low-density lipoprotein cholesterol LDL-C , high-density lipoprotein cholesterol HDL-C , triglycerides TG and lipoprotein a Lp a. Main classical risk factors for atherosclerosis include dyslipoproteinaemia, diabetes, cigarette smoking, hypertension and genetic abnormalities. Hypercholesterolaemia is considered one of the main triggers of atherosclerosis. The increase in plasma cholesterol levels results in changes of the arterial endothelial permeability that allow the migration of lipids, especially LDL-C particles, into the arterial wall.
It seems that you're in Germany. We have a dedicated site for Germany. Despite recent advances in the diagnosis and treatment of symptomatic atherosclerosis, available traditional screening methods for early detection and treatment of asymptomatic coronary artery disease are grossly insufficient and fail to identify the majority of victims prior to the onset of a life-threatening event. Morteza Naghavi and leading authorities from the Society for Heart Attack Prevention and Eradication SHAPE present a new paradigm for the screening and primary prevention of asymptomatic atherosclerosis. The text focuses on accurate, yet underutilized, measures of subclinical atherosclerosis, notably coronary artery calcium scanning and carotid intima-media thickness measurement. The authors introduce a comprehensive approach to identifying the vulnerable patients asymptomatic individuals at risk of a near future adverse event.
Мидж, тебе отлично известно, что Стратмор всего себя отдает работе. Он относится к ТРАНСТЕКСТУ как к священной корове. Мидж кивнула. В глубине души она понимала, что абсурдно обвинять в нерадивости Стратмора, который был беззаветно предан своему делу и воспринимал все зло мира как свое личное. Попрыгунчик был любимым детищем коммандера, смелой попыткой изменить мир. Увы, как и большинство других поисков божества, она закончилась распятием. - Хорошо, - сказала .
Она быстро проверила отчет программы в поисках команды, которая могла отозвать Следопыта, но ничего не обнаружила. Складывалось впечатление, что он отключился сам по. Сьюзан знала, что такое могло произойти только по одной причине - если бы в Следопыте завелся вирус. Вирусы были самой большой неприятностью, с которой сталкивались в своей работе программисты. Поскольку компьютеры должны были выполнять операции в абсолютно точном порядке, самая мелкая ошибка могла иметь колоссальные последствия.