Cardiovascular disease

Cardiovascular disease
Specialty	Cardiology

Cardiovascular disease refers to the class of diseases that involve the heart and/or blood vessels (arteries and veins). While the term technically refers to any disease that affects the cardiovascular system, it is usually used to refer to those related to atherosclerosis (arterial disease). These conditions have similar causes, mechanisms, and treatments. In practice, cardiovascular disease is treated by cardiologists, thoracic surgeons, vascular surgeons, neurologists, and interventional radiologists, depending on the organ system that is being treated. There is considerable overlap in the specialities, and it is common for certain procedures to be performed by different types of specialists in the same hospital.

Most Western countries face high and increasing rates of cardiovascular disease. Each year, heart disease kills more Americans than cancer. Diseases of the heart alone caused 30% of all deaths, with other diseases of the cardiovascular system causing substantial further death and disability. It is the number 1 cause of death and disability in the United States and most European countries. A large histological study (PDAY) showed vascular injury accumulates from adolescence, making primary prevention efforts necessary from childhood. By the time that heart problems are detected, the underlying cause (atherosclerosis) is usually quite advanced, having progressed for decades. There is therefore increased emphasis on preventing atherosclerosis by modifying risk factors, such as healthy eating, exercise and avoidance of smoking.

Risk factors

There are many risk factors which associate with (but are not all causes of) various forms of cardiovascular disease. These include the following:

• Age
• Gender, men under age 64 are much more likely to die of coronary heart disease than women, although the gender difference declines with age. (The gender difference is less pronounced in blacks than in whites, but it is still significant )
• Absence of key nutritional elements, such as omega-3 fats and polyphenol antioxidants
• Diabetes mellitus
• Hypercholesterolemia (elevated cholesterol levels) and abnormal lipoprotein particle profile (cholesterol subtypes)
• Elevated Heart Rate
• Tobacco smoking
• Higher fibrinogen and PAI-1 blood concentrations
• Elevated homocysteine, or even upper half of normal
• Elevated blood levels of asymmetric dimethylarginine
• High blood pressure
• Exposure to high levels of environmental noise
• Obesity, especially central or male-type obesity; apart from being linked to diabetes, this form of obesity independently increases cardiovascular risk, presumedly by inducing an inflammatory and procoagulant state
• Insulin resistance, especially when excess food calories are ingested
• Genetic factors/Family history of cardiovascular disease
• Physical inactivity/ Sedentary lifestyle
• Depression
• Stress

Although men have a higher rate of cardiovascular disease than women, it is also the number one health problem for women in industrialized countries. After menopause, the risk for women approaches that of men. Hormone replacement therapy alleviates a number of post-menopausal problems, but appears to increase the risk of cardiovascular disease.

Prevention

Attempts to prevent cardiovascular disease are more effective when they remove and prevent causes, and they often take the form of modifying risk factors. Some factors, such as sex (male or female), age, and family history, cannot be modified. Smoking cessation (or abstinence) is one of the most effective and easily modifiable changes. Regular cardiovascular exercise (aerobic exercise) complements the healthful eating habits. According to the American Heart Association, build up of plaque on the arteries (atherosclerosis), partly as a result of high cholesterol and fat diet, is a leading cause for cardiovascular diseases. The combination of healthy diet and exercise is a means to improve serum cholesterol levels and reduce risks of cardiovascular diseases; if not, a physician may prescribe "cholesterol-lowering" drugs, such as the statins. These medications have additional protective benefits aside from their lipoprotein profile improvement. Aspirin may also be prescribed, as it has been shown to decrease the clot formation that may lead to myocardial infarctions and strokes; it is routinely prescribed for patients with one or more cardiovascular risk factors.

One possible way to decrease risk of cardiovascular disease is keep your total cholesterol below 150. In the Framingham Heart Study, those with total cholesterol below 150 only very rarely got coronary heart disease.

Eating oily fish at least twice a week may help reduce the risk of sudden death and arrhythmias. A 2005 review of 97 clinical trials by Studer et al. noted that omega-3 fats gave lower risk ratios than did statins. Olive oil is said to have benefits. Studies of individual heart cells showed that fatty acids blocked excessive sodium and calcium currents in the heart, which could otherwise cause dangerous, unpredictable changes in its rhythm.

Awareness

Interestingly, although cardiovascular is the number one cause of death for individuals in modern society, a majority of young people are unconcerned about their risk for development of this disease. Atherosclerosis is a process that develops over decades and is often silent until an acute event (heart attack) develops in later life. Population based studies in the youth show that the precursors of heart disease start in adolescence. The process of atherosclerosis evolves over decades, and begins as early as childhood. The Pathobiological Determinants of Atherosclerosis in Youth Study demonstrated that intimal lesions appear in all the aortas and more than half of the right coronary arteries of youths aged 15–19 years. However, most adolescents are more concerned about other risks such as HIV, accidents, and cancer than cardiovascular disease. (reference: Vanhecke et al. Awareness, knowledge, and perception of heart disease among adolescents. EJCPR 2006;13:718-723.). This is extremely important considering that 1 in 3 people will die from complications attributable to atherosclerosis. In order to stem the tide of cardiovascular disease, primary prevention is needed. Primary prevention starts with education and awareness that cardiovascular disease poses the greatest threat and measures to prevent or reverse this disease must be taken.

Treatment

Treatment of cardiovascular disease depends on the specific form of the disease in each patient, but effective treatment always includes preventive lifestyle changes discussed above. Medications, such as blood pressure reducing medications, aspirin and the statin cholesterol-lowering drugs may be helpful. In some circumstances, surgery or angioplasty may be warranted to reopen, repair, or replace damaged blood vessels.

Research

The causes, prevention, and/or treatment of all forms of cardiovascular disease are active fields of biomedical research, with hundreds of scientific studies being published on a weekly basis.

A fairly recent emphasis is on the link between low-grade inflammation that hallmarks atherosclerosis and its possible interventions. C-reactive protein (CRP) is an inflammatory marker that may be present in increased levels in the blood in patients at risk for cardiovascular disease. Its exact role in predicting disease is the subject of debate.

Some areas currently being researched include possible links between infection with Chlamydophila pneumoniae and coronary artery disease. The Chlamydia link has become less plausible with the absence of improvement after antibiotic use (Andraws et al 2005).

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References

• Vanhecke TE, Miller WM, Franklin BA, Weber JE, McCullough PA. Awareness, knowledge, and perception of heart disease among adolescents. European Journal of Cardiovascular Prevention and Rehabilitation. October, 2006; 13(5): 718-723. ISSN 1741-8267
• Andraws R, Berger JS, Brown DL. Effects of antibiotic therapy on outcomes of patients with coronary artery disease. JAMA 2005;293:2641-7. PMID 15928286.
• Leaf A, Kang JX, Xiao YF, Billman GE. Clinical prevention of sudden cardiac death by n-3 polyunsaturated fatty acids and mechanism of prevention of arrhythmias by n-3 fish oils. Circulation 2003;107:2646-52. PMID 12782616.
• American Heart Association "Heart Disease and Stroke Statistics-2006 Update". http://www.americanheart.org/downloadable/heart/1140534985281Statsupdate06book.pdf
• Studer M, Briel M, Liemenstoll B, Blass TR, Bucher HC. "Effect of different antilipidemic agents and diets on mortality: a systematic review." Arch. Intern. Med. 2005; 165(7): 725-730.
• Rainwater DL, McMahan CA, Malcom GT, Scheer WD, Roheim PS, McGill HC Jr, Strong JP. Lipid and apolipoprotein predictors of atherosclerosis in youth: apolipoprotein concentrations do not materially improve prediction of arterial lesions in PDAY subjects. The PDAY Research Group. Arterioscler Thromb Vasc Biol. 1999; 19: 753-61.
• Mcgill, HC, Jr., Mcmahan, CA, Zieske, AW et al. Associations of coronary heart disease risk factors with the intermediate lesion of atherosclerosis in youth. The Pathobiological Determinants of Atherosclerosis in Youth (PDAY) Research Group. Arterioscler. Thromb. Vasc. Biol. 2000; 20: 1998–2004.

External links

• Sister to Sister Information about Women's Heart Disease
• NCP Cardiovascular Medicine A Journal Covering Clinical Cardiovascular Medicine
• Cholesterol Content in Food
• The lacking awareness of cardiovascular disease by youth A study by Dr Thomas E. Vanhecke, MD.
• American Heart Association
• World Health Organization cardiovascular disease site
• Heart disease 'costing UK £29bn' at BBC News, 14 May 2006
• Diet, Nutrition and the prevention of chronic diseases (including cardiovascular diseases) by a Joint WHO/FAO Expert consultation (2003). Summary by GreenFacts.
• Total Cholesterol Distribution vs. CHD deaths
• American Heart Month - National month devoted to discussion of heart disease