Diseases of the blood vessels
There is an extensive network of blood vessels in our body. They fall into two broad categories; arteries and veins. Like any other organ of the body, the blood vessels may also become diseased.
The diseases of the blood vessels are called vascular diseases. Many of us might know that with increasing age, a fatty substance called atheroma tend to accumulate along the inner wall (luminal surface) of the arteries.
The process of atheroma formation is called atherosclerosis — a condition that lies at the root of many arterial diseases. As the atheromas grow in size, they tend to encroach on to the arterial lumen causing its narrowing that leads to different degrees of blood flow obstruction. Such narrowing of arterial lumen is called stenosis.
Arterial stenoses may remain asymptomatic. However, significant stenoses almost invariably produce symptoms of inadequate tissue oxygenation (ischemia). A good example of such phenomenon is the ischemic chest pain one experiences when the coronary arteries are stenosed (angina pectoris). When the coronary stenosis is critical, such ischemia may turn into a heart attack (Myocardial infarction).
Similarly, critical carotid artery stenosis may give rise to symptoms of cerebral ischemia manifesting as events like stroke.
Atherosclerotic stenosis or occlusion of the iliac, femoral or popliteal arteries may cause ischemic leg pain called claudication — an event that is classically brought on by walking and relieved by rest.
Besides atherosclerosis, Buerger's disease is very important. The mechanism of arterial stenosis in Buerger's disease is inflammation and thrombosis of the small and medium-sized arteries and veins of the extremities which is thought to be an autoimmune reaction to tobacco. The disease manifests itself in the form of intermittent claudication (cramping leg pain on walking). In the most severe form, patients may present with gangrene in their feet or hand which often requires amputation. Since smoking plays a central role in the causation of arterial stenotic lesions in patients with claudication, quitting smoking is the single most important step in stopping the progression of the disease.
It is important to mention here that stenosis is not the only fate of an atherosclerotic artery. Rather, sometimes the reverse happens when the arterial walls are degenerated and weakened by atherosclerosis swell like a balloon. Such dilated segment of an artery is called an aneurysm. As the disease progresses, the wall of the aneurysm may become precariously thin which, at one stage, may give way to hemodynamic stress.
Rupture of an aortic aneurysm is a medical emergency in which patients suffer massive internal bleeding and inevitably succumb to death unless quickly intervened. In the western world, despite remarkable modernisation of emergency medical services, more than 75 percent of such patients ultimately die. It can be assumed that ruptured aortic aneurysm, which may remain asymptomatic constitutes a sizeable portion of the cases of unexplained sudden deaths that occur in our country.
Another kind of aortic disease that deserves mention here is aortic dissection in which blood enters the wall of the aorta through a small tear and advances distally or proximally creating a plane of cleavage within the wall. The disease manifests itself as a sudden crushing pain along the center of the upper and mid back. The implications of an aortic dissection can be serious when it affects a critical segment of the aorta.
Dissection often causes accumulation of a considerable amount of blood around the heart that creates pressure on it. Such phenomenon is called cardiac tamonade — a condition that calls for urgent intervention. Aortic root dissection may also jeopardise coronary artery flow causing coronary ischemia.
All of the arterial diseases discussed above have conventional surgical treatment. Although there is no question regarding the effectiveness of these surgical treatments, they are highly invasive and expensive. A number of minimally invasive treatment alternatives, which have been developed recently for such diseases are equally effective.
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