Unstable angina

Causes and Risks:
Coronary artery disease is by far the most common cause of unstable angina. A coronary artery spasm may cause angina in less than 10% of cases.

Narrowing (plaques) of the coronary arteries occurs and may be severe enough to cause stable angina with exertion or stress , or may not be severe enough to cause any symptoms at all. For reasons not understood, at some point these plaques may rupture and platelets and blood clots may form causing a relatively stable narrowing to become unstable ("high-grade"), limiting blood flow to a region of the heart even at rest.

In unstable angina, the chest pain may occur at rest, or there may be increase in the severity, frequency, or duration of the pain, with chest pain occurring at lower levels of activity. There may be a history of MI ( heart attack ). Diabetes mellitus , hypertension , myxedema , peripheral vascular disease , heart valve disease, cardiomyopathy , and atherosclerosis may also produce angina.

Risk factors for angina include being male, cigarette smoking , high cholesterol levels (in particular, high LDL cholesterol and low HDL cholesterol ), high blood pressure , diabetes , family history of coronary heart disease before age 55, sedentary lifestyle, and being more than 30% over ideal body weight . Occasionally, sudden overwhelming stress can precipitate an episode of angina.

Unstable angina occurs in approximately 6 out of 10,000 people.

Prevention:
The best prevention is to modify those risk factors that can be changed. Stop smoking , lose weight if overweight , and control blood pressure , diabetes , and cholesterol . Some studies have shown that modifying risk factors can prevent the progression of arterial blockages and can lead to decrease in the severity of blockages.

Aspirin, antianginal medications such as nitrates (nitroglycerin), beta-blockers, calcium channel blockers, or others may be prescribed to prevent the occurrence of angina and lessen its severity.

Symptoms:
  • pain or discomfort in the chest or adjacent areas
    • under the breastbone
    • may radiate to shoulder, arm, jaw, neck, back or other areas
    • often described as tightness, squeezing, crushing, burning, choking, aching
    • not sharply localized

  • pain may occur at rest
  • pain may be new onset

If a pattern of stable angina has been present, the development of unstable angina may be signified by a change in the pattern, frequency, or severity. It may also be signified by an increase in the use of nitroglycerin.

Signs and Tests:
A physical examination may reveal a change in blood pressure . Transient heart murmur or arrhythmias (irregular heart beats) may occur.

ECG changes that occur at rest, during pain, is often diagnostic.
Heart scans or coronary angiography of the heart are often performed.

Treatment:
This is a severe condition and usually requires hospitalization. The goals of treatment are reduction of symptoms and prevention of complications.

Rest if chest pain occurs.

Aspirin, heparin, and nitroglycerin (often by paste or intravenously) are given during an attack. Other medications include beta-blockers, calcium channel blockers, antianxiety medications, and medications to control blood pressure and abnormal heart rhythms .

Surgery may be recommended. CABG (coronary artery bypass grafting) or PTCA ( balloon angioplasty ) may be necessary.

Prognosis:
The outcome varies. Outcome depends on many factors, one of which is the severity of the underlying coronary artery disease . Progression to MI ( heart attack ), arrhythmias , or sudden death may occur.

Complications:



Call Your Healthcare Provider:

  • chest pain develops which has not been evaluated
  • known angina changes in frequency, severity, or pattern
  • known angina is not relieved with usual doses of nitroglycerin or is not relieved within 15 to 20 minutes.