At 75% luminal narrowing, patients experience symptoms associated with limited perfusion of cardiomyocytes, especially under strenuous conditions. Under physical exertion, CAD induces chest pain, termed stable angina. Stable angina may deteriorate into unstable angina, marking the initiation of Acute Coronary Syndrome, which may further deteriorate into a myocardial infarction. Risk factors for CAD include smoking, high cholesterol, obesity, and family history of CAD. Primarily, the accumulation of cholesterol in the bloodstream from high-fat diets lead to atherosclerotic occlusion and its clinical consequences. Therefore, preventative measures for CAD mainly involve diet changes. A diet low in saturated and trans fats with an abundance of vegetables, fruits, and grains may lower the incidence of CAD. Peripheral Artery Disease
Peripheral artery disease (PAD), or limb ischemia, affects the femoral, popliteal, or iliac arteries. PAD is caused by atherosclerotic plaques that occlude blood flow to extremities. Once blood flow is impeded, ischemic muscle cells switch from aerobic to anaerobic metabolism to cope with oxygen scarcity. Anaerobic metabolism, however, is energy-inefficient, lowering the concentration of the intracellular energy molecule, ATP, within muscles. ATP depletion leads to a leakage of calcium into muscle cells, disrupting various muscular components and eventually causing muscle fiber necrosis.Risk factors for PAD include old age, smoking, hypertension, and high cholesterol, with smoking being the greatest contributing factor. This is because tobacco smoke contains potent chemicals that severely increase the occurrence of PAD. Thus, primary prevention of PAD is achieved with smoking cessation.
Sudden narrowing leads to more severe consequences, given the lack of time for collateral vessels to grow. As such, coldness, numbness or even paralysis of the affected body parts may result.The commonest symptom of arterial occlusion is intermittent claudication, which consists of a painful, aching sensation in the affected muscle. This is often provoked with physical activity and relieved with rest. Pain and muscle aching may build up with walking, and accelerate with light jogging or walking uphill. Often, pain is relieved after several minutes of rest. However, affected individuals are limited to short spurts of activity, impairing their quality of life. For severe symptoms, the signs are usually visible and lead to ischemia. The clinical presentation of ischemia consists of the 6 Ps, including pallor, pain, paresthesia, paralysis, pulselessness, and poikilothermia. Affected individuals initially notice a paleness of the affected region and feel severe pain. As the condition worsens, the region appears bluish and numb. In extreme cases, this will give way to paralysis and poikilothermia, possibly requiring amputation of the affected limb. Types of arterial occlusion
Commonly observed types of arterial occlusion include thrombosis, atherosclerosis, and embolism. Embolism
An embolism involves the occlusion of blood vessels by an embolus. Arterial occlusion by an embolus is termed arterial embolism. An embolus is an agent that blocks blood flow by physically obstructing blood vessels. This includes gas bubbles, fatty deposits, amniotic fluid, blood clots, and foreign material. Arterial emboli occasionally detach from primary sites and travel via circulation to occlude secondary arteries, causing multiple ischemic sites.