Atherosclerosis
Atherosclerosis is the formation of a plaque (athero-) on the wall of the blood vessel making it hard or sclerosed (-sclerosis). This hard vessel has decreased diameter due to the plaque formation which can grow larger leading to significant vessel occlusion.
Risk factors such as hypertension, diabetes, smoking, high cholesterol/triglycerides, and platelet abnormalities can lead to the development of atherosclerosis. Sex and age also naturally predispose to this condition, with men being more commonly affected than women and the risk of atherosclerosis increasing with age.
Atherosclerosis can occur anywhere in the body but is more common in the abdominal aorta, coronary arteries, popliteal arteries, and internal carotid arteries. Stress on the vessel wall leads to injury to the endothelium. Macrophages infiltrate the injured endothelium and platelets aggregate and adhere to the endothelium. This activates the inflammatory response releasing cytokines and growth factors. Cytokines form the extracellular matrix. Hyperplasia of smooth muscle cells occurs which forms the fibrous cap.
Symptoms are generally asymptomatic if mild and are dependent on which vessels are affected. For instance, if the abdominal aorta is affected it can cause abdominal/back pain, coronary arteries can cause angina (chest pain/pressure), popliteal artery can cause leg claudication (pain and/or cramping), renal arteries can lead to high blood pressure or kidney problems.
Complications include aneurysms, thrombus formation, hypertension (due to atherosclerotic narrowing of renal artery), cerebral atrophy (involvement of circle of willis), and peripheral artery disease (PAD).
Ankle Brachial Index (ABI) calculation can help diagnose atherosclerosis in the lower limbs. A ratio less than 0.9 indicates presence of PAD. Angiography and duplex ultrasonography can be used to visualize the vessel defects.
Initial treatment includes minimizing risk factors (stop smoking, diet modification, exercise, weight loss, and stress management). Medications such as cilostazol prevent platelet aggregation. Surgical revascularization may be required.
