Magnitude of the Problem

Thrombosis

Thrombosis of an atherosclerotic artery or a vascular grat is another major cause of acute arterial occlusion of the extremities. As Virchow suggested in 1856, thrombus formation is the result of an interaction between an injured surface, stasis and the hypercoagulability of blood:

Arterial thrombosis most oten develops at the points of severe stenosis. Since the course of atherosclerotic disease is chronic, a collateral network will have already developed and the clinical picture will be milder compared with arterial embolism. However, a thrombus can be formed in the absence of signiicant pre-existing stenosis, particularly when the surface of the plaque is ulcerated or ater an intraplaque haemorrhage resulting in sudden arterial occlusion.

Low-low conditions, such as congestive heart failure, hypovolaemia, hypotension of any cause or decreased blood low due to a more proximal stenosis.

Hypercoagulable states, such as myeloproliferative disorders, hyperviscosity syndromes and coagulation disorders, may contribute to thrombosis of the diseased artery.

Other causes of arterial thrombosis include:

Arterial aneurysms, with the risk of thrombosis being higher the more peripherally the aneurysm is located.

Arterial by-pass grat thrombosis, which frequently induces acute limb-threatening ischaemia, as the grat has usually allowed collateral vessels to regress. Early grat failure, within the irst postoperative month, is usually due to a technically suboptimal result, inappropriate indication or a transient episode of hypotension. Late grat failure, ater 1 month, is secondary to intimal hyperplasia at the anastomotic sites or to progression of atherosclerotic disease.

Aortic dissection.

Fibromuscular dysplasia, occasionally involving the iliac arteries.

Cystic adventitial disease, usually afecting the popliteal artery and rarely the femoral.

hromboangiitis obliterans, involving medium-sized muscular arteries.

Various arteritides, such as Takayasu’s aortitis and giant cell arteritis.

Compartment syndrome.

Еhoracic outlet syndrome.

Popliteal entrapment syndrome.

Ergotism.

It is difficult to find accurate incidence figures on acute leg ischemia. Data from some reports are given in Table 2. The numbers listed do not include conservatively treated patients or those whose legs were amputated as a primary procedure. The incidence increases with age and is seen with equal frequency in men and women. Regardless, the frequency indicates that it is a very common problem.

Дата добавления: 2014-12-23