Chronic occlusions of arterial vessels

Chronic occlusions of arterial vessels lead to a decrease in blood flow in the anatomical region or organ. With constant perfusion pressure, i.e., uniform blood flow, the pressure below the occlusion site decreases only when the lumen of the vessel is narrowed by more than 50%. This pattern becomes relative due to the presence of peripheral resistance. With a high peripheral resistance, even a narrowing of the lumen by 50% will not lead to a decrease in blood flow with a decrease in pressure in the occlusion zone. With insignificant peripheral resistance in the same situation, the pressure in the occlusion zone decreases with a decrease in blood flow. In stenosis, the organ blood flow depends on the influx to the occlusion zone (ie, perfusion pressure), the degree of narrowing (percent of vessel narrowing), the value of peripheral resistance and the viscosity of the blood. The morphological result of occlusion (i.e., increasing blood flow velocity and turbulence of blood flow) is poststenotic dilatation, the development of aneurysms, thrombi and peripheral embolism, collaterals. Collateral blood flow is a consequence of significant stenosis with a large pressure gradient between the pre- and poststenotic segments of the vessel. There is an expansion of small preformed vessels with their true anatomical growth and the formation of sufficient roundabout flow. The organic narrowing of the vessel is not completely compensated, the clinical manifestations appear initially at the load.

Chronic violations of the arterial blood flow are divided into 3 groups: angioneuropathy (Raynaud's disease, etc.); Angiopathy; Angiorganopathy. In the first two forms, in the absence of the effect of conservative measures, lumbar or thoracic sympathectomy is used. With angiorganopathy, accounting for up to 90% of all obliterans, surgical methods of treatment have a major role. Most often among organopathies occurs obliterating atherosclerosis and less often obteriruyuschy endarteritis and thromboangiitis.