Arteriosclerosis is a group of diseases with the characteristic features of thickening and loss of elasticity of the arterial walls. A specific type of arteriosclerosis is atherosclerosis. Atherosclerosis occurs when fats, cholesterol and other substances collect in and on the artery walls forming a plaque. The plaque can restrict or completely block the blood flow along the affected artery. Once a plaque bursts, the formation of a blood clot follows.
Atherosclerosis develops gradually, but progressively. The signs and symptoms only appear during moderate to severe blockage of the artery. The symptoms will depend on the location of the affected artery.
There is no exact single cause of atherosclerosis. It usually starts with a damage or injury on the inner artery wall caused by high blood pressure, cholesterol, triglyceride and sugar levels, smoking and inflammation from other diseases. Blood cells and other substances migrate to the site of injury and eventually harden. The plaque narrows the arteries, but can also break off and enter the bloodstream. This can lead to other conditions such as heart attack.
As the arteries become more blocked, several complications may arise. Coronary artery disease can develop and lead to heart attack or heart failure. A narrowed artery near the brain can lead to stroke. Aneurysms can develop which increase the risk for internal bleeding. Narrowed arteries leading to the kidneys can cause chronic kidney disease.
Diagnosis of atherosclerosis usually starts with a physical exam and medical history. There is a weak or absent pulse and decreased blood pressure on the affected area. Whooshing sounds can be heard with a stethoscope and evidences of poor wound healing are observed on the affected area. Confirmatory tests such as blood tests, Doppler ultrasound and ankle-brachial index can be done to confirm and locate the affected artery.
Commonly Prescribed Drugs
- Antihyperlipidemic agents decrease the levels of low-density lipoprotein (LDL) or the bad cholesterol and/or increase the high-density lipoprotein (HDL) or good cholesterol in the body. An example of this are the HMG-CoA reductase inhibitors or the statins and the fibric acid derivatives such as fenofibrate and gemfibrozil.
- Antiplatelets are given to reduce the risk of blood clot formation by decreasing the ability of platelets to stick together. Examples are aspirin and clopidogrel.
- ACE inhibitors lower the blood pressure which slows down the progression of atherosclerosis. These agents inhibit the enzyme that produces Angiotensin II, a substance that constricts blood vessels and increases blood pressure. Examples include captopril, enalapril and perindopril. Side effects: dry cough, increase in potassium levels, fatigue
- Calcium channel blockers lower blood pressure by preventing reentry of calcium in heart muscle and blood vessel. These agents relax and dilate the muscles of blood vessels. Common examples include amlodipine, diltiazem and verapamil. Side effects: palpitation, swelling of lower extremities, flushing
- Diuretics or water pills reduce blood pressure by helping the body excrete sodium and water. This lowers the volume of fluid in the blood vessels which decreases the blood pressure. A common thiazide diuretic is hydrochlorothiazide. Furosemide is a loop diuretic while spironolactone is a potassium-sparing diuretic. Side effects: increased urination, mineral loss, muscle cramps
Treatment and Management
Lifestyle changes are usually the appropriate treatment for atherosclerosis to prevent its progression. These include regular exercise to improve blood circulation and lower blood pressure, and eating a healthy diet based on fruits, vegetables and whole grains.
Quit or avoid smoking. Smoking directly causes damage to the arteries.
Invasive and Surgical Procedures
- Angioplasty and stent placement compresses the plaque deposits against the artery walls and leaves the artery open using the mesh tube/stent. This is done on a blocked or narrowed artery.
- Endarterectomy surgically removes the fatty deposits on the walls of the affected artery.
- Coronary artery bypass graft (CABG) is done by directly attaching a blood vessel on the aorta to avoid the blockage. This redirects the blood flow away from the blocked or narrowed artery.