The aorta and its branches are subject to atherosclerosis. The branches feeding the lower limbs are a frequent site of arterial blockage, causing poor blood flow in the legs and feet. If this condition is not treated, gangrene may set in, necessitating amputation of the affected limb. Treatment involves balloon angioplasty or surgery to bypass the affected portion of the artery.
The aorta and other arteries may also develop an aneurysm, a weakened portion of the artery's wall that bulges outward and may rupture suddenly and fatally. Severe aneurysms are usually treated surgically to prevent rupture.
Raynaud disease, a disorder of the small arteries in the extremities, leads to numbness of the fingers and toes. It is often of unknown origin but may be secondary to some known disorder, and it is usually not serious.
The most serious disease of the veins is thrombophlebitis, which involves the formation of one or more blood clots, usually in the leg or pelvis. Symptoms include pain and inflammation, but some patients may have no symptoms. Symptomless patients are at particular risk of having a clot break off and be carried away by the bloodstream. A breakaway clot is known as an embolus, and if it becomes lodged in the lungs, it is called a pulmonary embolus and can be fatal. Patients who are bedridden or otherwise immobilized are at higher risk for thrombophlebitis and pulmonary embolism.
As a preventive measure, low doses of a blood thinner may be given to patients at high risk of developing blood clots. Once a clot occurs, treatment involves the use of blood-thinning or clot-dissolving drugs.
Varicose vein disease is widespread but not life-threatening; however, it can cause considerable discomfort and inconvenience. It tends to affect veins of the lower limbs. These veins contain regularly spaced valves, which normally ensure that blood flows toward the heart. If one or more valves no longer works properly, blood leaks backward, causing the involved vein to become distended. Symptoms include pain, tiredness, and/or tingling of the affected area. In some untreated cases the limb may become ulcerated because swelling of the leg impairs the arterial blood supply. Some varicosities are relieved by elastic support stockings. In other cases the diseased vein can be injected with a chemical that causes it to dry up so blood flow will then be rerouted through adjacent veins. Patients may also undergo surgical removal of the varicose segment.