The Prevalence of Peripheral Vascular Diseases - Term Paper Example

? Peripheral Vascular Disease Peripheral Vascular Disease The heart is the vital organ that pumps blood throughout the body. Along with the blood vessels, heart forms the circulatory system which sustains the blood circulation in the body to perfuse every cell and tissue with the oxygen and nutrient rich blood. The diseases affecting circulatory system range from those affecting the heart to those affecting the blood vessels. The diseases that affect the peripheral blood vessels are considered under the term Peripheral Vascular Disease. These disorders mainly affect the vessels supplying blood to the peripheral parts of the body, i.e. legs, arms and the viscera in thorax and abdomen. The pathology in the vessels can be functional or organic. In peripheral vascular disease due to functional pathology there are no structural lesions in the vessels and the circulatory upset is due to certain other mechanisms, like spasm of the vessels. Primary Raynaud’s phenomenon and secondary Raynaud’s disease are the examples of vascular problems having functional abnormalities. Organic pathology refers to structural changes in the blood vessels which lead to the circulatory disturbance. This category includes the peripheral arterial disease (PAD) due to atherosclerosis, which is a major cause of circulatory morbidity and mortality all over the world, especially in developed nations (Alonso et al, 2011). The disease manifestations are due to the obstruction of the vessels and the resultant ischemia. The symptoms depend upon the site of occlusion and the severity is related to the degree of obstruction. The various types of vascular diseases, their underlying pathology and disease manifestations will be discussed in the paper. The common pathology underlying most of the peripheral arterial diseases is the endothelial damage and the accumulation of fatty deposits. The lipid rich ‘fatty streaks’ are the earliest change and occur at the sites of stress and sheer force in the vascular tree (like bifurcations of arterial branches). The altered endothelial function is related to the ensuing slow inflammatory process. The lipid rich foam cells which are the macrophages are formed when monocytes attach to the endothelial cell receptors and take up low density lipoproteins (LDL) from the plasma. As these cells are worn out, they release their contents and the lipid rich pool forms in the intima of the vessels. The activated macrophages produce growth factors, cytokines as well as other inflammatory markers. Under the influence of these mediators, smooth muscle cells migrate to the intima and stabilize the thrombus. The acute symptoms of disease occur when the inflammatory process by macrophages overrides the repair attempts of the smooth muscle cells. Such plaques are known as vulnerable plaques. On the other hand, if the response by smooth muscle cells predominates, the lesion is covered by a fibrous cap and becomes a stable plaque. Further lipid deposition in such plaques results in an increase in the size of these plaques, which then continue to occlude the vessel until an acute event like rupture or total occlusion brings them to the clinical notice (Guyton et al, 2000). The prevalence of peripheral vascular diseases increases with age and the black populations are affected more commonly. The major risk factors for the peripheral vascular disease are smoking, diabetes, hyperlipidemia, and hypertension. Most individuals remain asymptomatic for years. It is only when about 70% lumen of the vessel is compromised that the disease manifests itself at rest. This is known as critical stenosis. In the long standing cases where development of occlusion is slow, collateral vessels develop and maintain the circulation. Any acute event in the face of such formerly, apparently healthy circulation can result in drastic consequences. The thrombi can become detached to become emboli and occlude other peripheral vessels (Blue toe/ finger syndrome). If the embolic load is high, sudden occlusion of major arteries can be fatal (Boon et al, 2006). A great majority of the peripheral vascular diseases affect the lower limb. PAD affects leg eight times more than the arm (Boon et al, 2006). The lower limb ischemia can be assessed clinically and may present in two different ways, either as intermittent claudication or as critical limb ischemia, depending upon the degree of obstruction and severity of the disease. Intermittent claudication refers to the pain that is brought on by walking and is relieved at rest. The cyclic pain occurs after a person covers a particular distance, called claudication distance. As the person stops walking, the pain is relieved, only to occur again as the walking is resumed. The pain can occur in the thigh or the buttocks, but since the vessel that is usually affected in intermittent claudication is the superficial femoral artery, the pain is mostly felt in the calf (Shearman 1989). Critical limb ischemia is the more severe form of disease affecting the vessels at many levels. The ischemic pain occurs even at rest, thus it is sometimes called night pain as well. The severity of the pain can mark the need for opiate analgesia. Due to the critical reduction in tissue perfusion, ulceration and eventually gangrene supervenes. The level of decreased pressure in the lower limb is assessed by measuring the ankle: brachial pressure index (ABPI). In healthy individuals, the ABPI is above 1. Moderate decrease is observed in ABPI in intermittent claudication (0.5- 0.9), whereas in critical limb ischemia, the pressure ratio falls to below 0.5. The pulses distal to the obstruction are either weak or absent and auscultation reveals bruits due to turbulent blood flow across the obstructed vessels. Other features observed due to the decreased blood flow include reduced skin temperature, loss of hair, thin and brittle nails and muscle wasting. Positive Buerger’s sign is observed when the limb becomes pale on elevation and red when it is kept dependent (Boon et al, 2006). Spasm of the peripheral vessels gives rise to a number of conditions. Raynaud’s disease (primary Raynaud’s phenomenon) is the disease sequence of alterations in the peripheral arteries that are triggered by stimuli like cold and emotional extremes. The initial reduction in blood flow due to the spasm makes the digits turn pale; the digits then become cyanotic due to the stasis of deoxygenated blood. The sequence reverses when the reactive hyperaemia makes the digits flush. This benign condition runs in families and afflicts 5 to 10% women in temperate areas. The whole sequence of events can be avoided by refraining from the inciting agents like cold. A distinct entity, Raynaud’s syndrome (secondary Raynaud’s phenomenon) refers to the static obstruction of the peripheral vessels supplying the digits. It occurs in association with the disorders of the connective tissues (systemic sclerosis) and can also occur with use of power tools that induce vibrations (Boon et al, 2006). This condition is particularly harmful as there is a chance of ulceration and gangrene. Such consequences can be avoided by protecting the digits and using antibiotics if infection occurs. Prevention plays a central role and lifestyle modifications can alter the outcome of the disease (Wann-Hansson, 2005). It is important for the patients to stop smoking and take regular exercise, i.e. at least 30 minutes, three times a week. Control of diabetes and dyslipidemias is essential. Diabetes predisposes to infections and impairs the healing ability. Reduction in blood cholesterol should be achieved by introducing diet modifications supplemented by Statin therapy. Since atherosclerosis is the culprit behind major morbidity and mortality associated with the vascular disease, the diagnosis and progression of concomitant conditions like coronary heart disease and hypertension should be sought and dealt with appropriately. Antiplatelet agents like Aspirin can be prescribed if needed. Thus, Prompt recognition and treatment of the peripheral vascular diseases can save the patients from the septic death or disability due to amputation and help them lead healthy lives comparable to the average healthy lifespan of the general population (Boon et al 2006). References 1. Alonso, A., McManus, D., & Fisher, D. Z. (2011).Peripheral vascular disease. Sudbury, Mass: Jones and Bartlett Publishers. 2. Boon, N. A., & Davidson, S. (2006). Davidson's principles & practice of medicine. Edinburgh: Elsevier/Churchill Livingstone 3. Guyton, A. C., & Hall, J. E. (2000). Textbook of medical physiology. Philadelphia: Saunders. 4. Shearman, C. P., & United Medical and Dental Schools of Guy's and St. Thomas's Hospitals . (1989). Intermittent claudication: A study of its assessment and associated pathophysiology. London: University of London 5. Wann-Hansson, C. (2005). Living with peripheral arterial disease: Quality of life and the patients' view of meaning. Lund: Dept. of Health Sciences, Univ. Read More