Atherosclerosis is a medical condition characterized by stiffening of the arteries of the body due to accumulation of fatty substances along the inner wall of the arteries. Arteries are the blood vessels which carry oxygen and other nutrients to the different organs of the body, hence stiffening and thereby gradual narrowing of the arteries lead to inadequate blood flow through them. Thus there is poor oxygen and nutrient supply to the different organs of the body leading to impairment of their functions.
Atherosclerosis is a type of arteriosclerosis however both the terms are often used interchangeably. This is a progressive disease which may start as early as during childhood and gradually progress to produce symptoms in the later years of life.
Common risk factors include chronic high blood pressure, diabetes, abnormality in lipid metabolism like high cholesterol level, family history, smoking etc. Although in many patients atherosclerosis is silent (does not produce any evident symptoms) it may lead to number of life threatening complications like heart attack (myocardial infarction), brain stroke, aneurysm etc.
Currently there are several treatment options to prevent and manage atherosclerosis effectively. These are change in life style pattern, intake of drugs like cholesterol lowering agents, antiplatelet drugs, beta blockers, ACE inhibitors, calcium channel blockers, certain interventions like angioplasty and placement of stents etc.
This condition develops gradually over several years and mild form of the disease usually does not produce any symptom. Symptoms usually appear when the supplying artery to any particular organ becomes narrow and stiff to such an extent that adequate blood flow through that particular artery becomes very much compromised. As a result oxygen as well as nutrient supply to these organs is also decreased resulting into various symptoms.
Symptoms depend upon the organ involved, like
1. Cardiovascular symptoms: these symptoms occur when there is narrowing and stiffening of the coronary arteries resulting into poor blood supply to the heart muscles (ischemia). Hence cardiac function is compromised. Common presenting symptoms include crunching chest pain (left sided), with excessive sweating, apprehension, lightheadedness even complete black out.
2. Central nervous system symptoms: these symptoms appear whenever the arteries supplying the brain tissue is narrowed leading to poor blood supply to the brain. Poor oxygenation to the brain may lead to sudden black out (transient ischemic attacks). Again complete stoppage of blood supply (oxygenation) due to clot formation (following rupture of the atherosclerotic plaque) leads to brain ischemia and consequently ischemic brain stroke. In some patients the stiff atherosclerotic artery may rupture leading to bleeding in the brain tissue and consequent hemorrhagic brain stroke. Presenting symptoms of the both types of stroke depends upon the area of the brain involved however common symptoms are slurring of speech, paralysis of facial muscles leading to deviation of mouth, dripping of saliva, inability to close the eyes, weakness to complete paralysis of the limbs (upper and or lower limbs) etc.
3. Kidney symptoms: if the supplying arteries of the kidneys are affected then there is chance of high blood pressure even complete shut down of renal functions (renal failure)
4. Symptoms of peripheral artery disease: Symptoms may also arise if the supplying arteries to the limbs are also affected by atherosclerosis. In these cases numbness to pain may occur during walking in the legs (intermittent claudication). Sometimes poor blood supply to arteries of limbs may lead to gangrene, decreased sensitivity to heat and cold and hence increased tendency of injury etc.
5. Symptoms may also arise if the supplying arteries to the genitals area affected. Erectile dysfunction is one of the most common presenting symptoms.
Atherosclerosis in the long run may lead to number of complications like coronary artery diseases like angina, heart failure and heart attack (myocardial infarction), cerebrovascular accidents like brain strokes, peripheral artery diseases and aneurysm. Aneurysm is characterized by abnormal balloon like swelling of the wall of the affected artery (usually large arteries like aorta are affected) and if it bursts it may kill the patient due huge blood loss.
The exact underlying cause of this slowly progressive health condition is not known however several factors which contribute to atherosclerosis are already been identified. Damage to the internal wall of the arteries is one of the important contributors. This usually occurs in patients of high blood pressure, abnormal lipid metabolism (high cholesterol level), diabetes, smoking, suffering from other inflammatory diseases like arthritis, lupus etc.
Number of cells like white blood cells and other substances tend to form clump at the damaged site on the inner wall of the artery. With time other substances like lipids also contribute in the clump (plaque) formation making the otherwise flexible arterial wall stiff. Next when the part of the atherosclerotic plaque breaks off and enters the general blood circulation (thrombus) clotting at that site may further narrow the already narrow lumen of the artery. The dislodged thrombus may also get lodged at a different site (embolus) leading to narrowing of that artery.
Common risk factors include family history of atherosclerosis, high blood pressure, diabetes, smoking, leading sedentary life, lack of exercise, excessive body weight (obesity) etc.
Despite all the complications mentioned above the good news is that atherosclerosis is both preventable and curable. Treatment options are
1. Life style pattern changes like regular exercise, quitting smoking, eating healthy diet, moderate drinking etc
2. Drugs like
a. LDL, the bad cholesterol lowering drugs like statins, drugs which boost HDL, the good cholesterol production like fibrates etc
b. Antiplatelet drugs like low dose aspirin, clopidogrel etc
c. Beta blockers
d. ACE inhibitors like captopril etc
e. Calcium channel blockers
f. Diuretics like furosemide
g. Thrombolytic therapy by administering alteplase, reteplase in heart attack etc
3. Surgical interventions like angioplasty and stent placement, coronary bypass surgery, endarterectomy etc.