Ischemia - what is this disease?
The role of collateral circulation
The human body is designed so wisely that has left collateral vessels, which open when needed and trying to help in the supply of ischemic tissue. This process requires time. It is proved that collaterals begin to work, when there is a pressure drop in the bloodstream and oxidized products of cells, nepolokivci oxygen, irritate the nerve endings.
Divided the collateral circulation on the capacity for rapid elimination of insufficiency of blood supply at 3 degrees:
- absolutely sufficient — the total diameter of the auxiliary vessel is equal to or exceeds shtrobirovaniya large vessel ischemia is removed quickly, the organ damage does not occur;
- relatively sufficient — all diameter of collaterals is smaller than the lumen of the damaged vessel, the opening is slow, and violations are removed immediately, there is a failure of tissue respiration, lack of oxygen;
- absolutely insufficient — combined forces collaterals is unable to replace the terminated flow, there is a heart attack on. This is typical of diseases such as myocardial infarction and ischemic stroke.
Allocate 2 types of damage:
- acute ischemia can develop quickly with a sudden thrombosis or embolism of a large vessel, collaterals do not have time to connect to the blood circulation of the affected area, so the result is a life-threatening disease;
- chronic ischemia is formed gradually with the growth of atherosclerotic plaque, slow the compression of the artery. Collaterals gradually take over the functions of the tissue supply. Clinical manifestations in this form are detected much later. For example, in electrocardiography find signs of myocardial infarction, which the patient didn't even know. So there is a painless form of ischemia.
Diagnosis of ischemia is carried out using objective methods: electrocardiography, echocardiography, research vessels of the fundus (ophthalmoscopy), ultrasound of the heart, electroencephalography, angiography of the vascular bed. With their help it is possible to identify manifestations of ischemia:
- the decrease in the number and caliber of blood vessels, of the small arterioles collapses and ceases to function;
- blanching and reduction in the size of the ischemic area of tissue due to insufficient blood supply;
- the temperature decrease in the affected tissues due to the cessation of metabolic processes;
- the occurrence of pain, caused by irritation of nerve endings oxidized products of cell activity.