Causes Of Angina And Microvascular Angina

Causes of angina and microvascular angina

     The main cause of angina, both unstable angina and myocardial infarction is the coronary artery disease. Coronary artery disease occurs when buildup plaques appear over the internal walls of coronary arteries and thus reduces the blood flow to the heart. In the majority of persons, coronary heart disease begins in adolescence and develops over the years.

     Elevated cholesterol, hypertension and smoking, deteriorates the arteries and contribute to the buildup plaques. The process of forming the plaques is called atherosclerosis. Plaques are deposits of cholesterol, calcium and other substances covered by a fibrous capsule. If there will be a sudden disturbance in the blood pressure, the artery will contract suddenly or if other factors are present (as inflammation), the fibrous capsule of the buildup plaque can break or crack, being the causes of angina The body will try to repair that rupture or fissure, in the same way it fix a skin lesion, by forming a thrombus at the capsule surface. Formed thrombus may completely obstruct the artery, blocking the blood flow to heart muscle and thus cause heart attacks. Newly-formed plaques have the highest risk of rupture. Fibrous capsule of a newly formed plaque buildup is more likely to break or to crack (more unstable) than a thicker capsule of an older plaque.

     Buildup plaques are not always the cause of angina. In some cases, rarely, the coronary spasm and the contracture can completely obstruct the blood flow and cause heart attacks. Most often, in these cases, all atherosclerosis is involved, but there are cases in which other factors produce the spasm. Cocaine, cold weather, emotional stress can cause episodes of arterial spasm. In many other cases is not known the cause of these spasms.

     Thrombi formed on a plaque buildup broken or cracked, may not be large enough to block the artery completely, but may reduce the blood flow in the territory vascularized of the artery, causing unstable angina. Unstable angina may be a sign that would follow a myocardial infarction, because that thrombus can grow in size and completely to obstruct the artery. If the thrombus is dissolved, immediately myocardial will be avoided, but the body will try over time to repair the injured capsule plaque buildup. Also a new repaired buildup plaque can be unstable. Likely to break again is high, thus being an important risk factor for a new myocardial infarction.

Precipitating factors

     In many cases is not known for sure the cause of occurrence of angina attack. Sometimes the body releases adrenaline and other hormones into the bloodstream in response to some intense emotions like anger, fear. Strenuous exercise, emotional stress, lack of sleep, and over nutrition can also be precipitating factors, meaning the causes of angina. Adrenaline increases the heart rate and the blood pressure and the coronary spasm, things that can cause the rupture of an unstable buildup plaque. Cocaine and nicotine, which can be found in tobacco products, can produce similar effects.

Microvascular angina

     Coronary X syndrome (microvascular angina) is a condition that is manifested by unstable retrosternal pain, with angina character, often with signs of myocardial ischemia, in the absence of coronary vessels damage. Diagnosis of microvascular angina determines whether there is the following:

• Angina-type pain (retrosternal pain with constrictive character that takes several minutes)
• Characteristic ECG changes during exercise,
• Coronary angiography shows normal coronary arteries,
• Do not induce coronary spasm in coronarography.

Aetiology of microvascular angina

     Nobody knows for sure but there are several theories. The most important theory argues that microvascular angina is due to a poorly defined condition of small vessels in heart muscle (vessels too small to be seen at coronarography). The second major theory supports the existence of certain "hypersensitivity" to cardiac pain. It is quite possible that patients with microvascular angina to present the two cases.

Incidence of microvascular angina

     This disease can affect anyone but is especially seen in young women (pre-menopausal). Doctors see a strong association between microvascular angina and a certain psychiatric disorders such as panic attacks.