Overview
Unstable angina is a clinical syndrome caused by acute myocardial ischemia, and it is an angina between stable angina and acute myocardial infarction. It includes incipient angina, worsening exertional angina, resting angina, recumbent angina, and post-infarction angina. Along with ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction, it is called acute coronary syndrome. Most unstable angina develops from stable angina.
Etiology
The development of unstable angina is closely related to plaque damage or plaque rupture. Platelet aggregation or wall thrombus formation is often seen at the plaque rupture, and the severity of luminal obstruction is related to the amount of wall thrombus. Vasoconstriction or spasm may also be involved in episodes of unstable angina because of the exposure of subcutaneous tissue after plaque rupture.
Symptoms
1. Primary angina pectoris
The duration of the disease is less than 1 month, and angina has never occurred before. It may occur at rest, during general activities or during physical labor, with no obvious regularity. The angina threshold fluctuates greatly, the condition is unstable in the incipient stage, and the probability of cardiac machine infarction is higher.
2. Worsening exertion type angina pectoris
Patients with stable angina have a sudden increase in the number of angina attacks within one month, prolonged duration and aggravation, without obvious triggers, sometimes not relieved by rest, with a significant increase in nitroglycerin consumption and a progressive decrease in activity tolerance.
3. Resting angina
Resting angina refers to angina that occurs at rest or under mild exertion. There are two clinical types: ① angina pectoris only occurs in the resting state, its attack characteristics and variant angina pectoris is similar, but during the attack ST-T depression. Resting angina that occurs in the presence of severe coronary artery obstruction. It is the most serious type of unstable angina. Most of the resting angina is combined with exertional angina, and its resting angina is a manifestation of the late stage of exertional angina, which often occurs at night.
4. Post-myocardial infarction angina pectoris
Post-myocardial infarction angina refers to angina that occurs within 48 hours to 1 month after acute myocardial infarction. These patients have a high probability of reinfarction. Post-myocardial infarction angina mainly occurs 2-14 days after acute myocardial infarction, and is most common in the second half of the night and early morning. It is mostly manifested as spontaneous angina pectoris or mixed angina pectoris.
5. Prone angina
Recumbent angina is characterized by both resting angina and exertional angina.
Examination
1. Electrocardiogram
During angina attack, there is obvious ST segment depression, sometimes T wave inversion is seen, and ST-T is basically normalized after angina relief.
2. Coronary angiography
Most of the first-type angina pectoris is single vessel lesions, and most of the unstable angina pectoris developed from long-term stable angina pectoris is multi-branch lesions. Recumbent angina is often accompanied by severe stenosis of three vessels with complete obstruction of a single vessel.
Diagnosis
A sudden increase in the number of angina attacks, prolonged duration, lack of effect of nitroglycerin, and attacks below the level of previously well-tolerated labor or at rest are basically diagnostic of the disease.
Differential diagnosis
1. Resting angina needs to be differentiated from recumbent angina.
Both are prone to attacks at night, but the former has no obvious relationship with myocardial oxygen consumption, while the latter has a clear relationship with the increase in myocardial oxygen consumption.
2. Stable angina pectoris
The pain is located behind the sternum, the range is not limited, can occur in the upper abdomen, pharynx, jaw, etc., often radiating to the left shoulder, the left upper arm, the inside of the left finger. The nature of the pain is varied, with obvious triggers, and can be induced by physical labor, exercise, and emotional excitement. The duration of the attack and the mode of relief are relatively consistent.
3. Non-ischemic chest pain
Short seconds of stabbing pain or lasting for hours of hidden pain, chest pain is often fixed at one point, can be clearly pointed out, mostly appeared after exertion, chest pain is related to respiration or other movements affecting the thorax, and can be transferred by other factors, and can be relieved after 10 minutes of containing nitroglycerin.
4. Gastrointestinal diseases
It is related to body position and meal time, and is relieved significantly by taking acid-control preparations.
5. Biliary colic
Long duration, mostly located in the right upper abdomen, localized pressure pain, may be accompanied by fever, leukocytosis, scleral yellowing.
Treatment
1. General treatment
Bed rest, intermittent oxygen intake, fluid or semi-fluid food.
2.Drug treatment
Intravenous nitroglycerin for 24～48 hours, after 48 hours, oral nitrate drugs can be chosen to continue the treatment. Other drugs include beta-blockers, calcium channel blockers, antithrombotic and antiplatelet therapy.
3. Surgical treatment
Surgical intervention.
Prognosis
Acute myocardial infarction occurs in 5% to 15% of patients with unstable angina, depending mainly on the severity of coronary artery disease. The best prognosis is for patients whose angina resolves completely after intervention.