What is Angina
DEFINITION
Angina pectoris is characterized by discomfort that occurs when myocardial
oxygen demand exceeds supply. Myocardial ischemia can be asymptomatic (silent
ischemia), particularly in diabetic patients. Angina can be subdivided as follows:
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1. |
Chronic
(stable)
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a. |
Usually
follows a precipitating event (e.g., climbing stairs, sexual intercourse, a
heavy meal, emotional stress, cold weather). |
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b. |
Generally
same severity as previous attacks; relieved by rest or the customary dose of
nitroglycerin. |
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c. |
Caused by a
fixed coronary artery obstruction secondary to atherosclerosis. The presence of
one or more obstructions in major coronary arteries is likely; the severity of
stenosis is usually more than 70%.
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|
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2. |
Unstable
(rest or crescendo)
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a. |
Recent
onset. |
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b. |
Increasing
severity, duration, or frequency of chronic angina. |
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c. |
Occurs at
rest or with minimal exertion.
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|
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3. |
Vasospastic
angina (Prinzmetal's variant)
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a. |
Occurs at
rest. |
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b. |
Manifests
electrocardiographically as episodic ST-segment elevations. |
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c. |
Caused by
coronary artery spasms with or without superimposed coronary artery disease
(CAD). |
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d. |
Patients are
also more likely to develop ventricular arrhythmias.
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|
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4. |
Microvascular
angina (syndrome X)
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a. |
Refers to the
condition in patients with normal coronary angiograms and no coronary spasm but
chest pain resembling angina and positive exercise test results.
|
| |
b. |
Defective
endothelium-dependent dilation in the coronary microcirculation may contribute
to the altered regulation of myocardial perfusion and the ischemic
manifestations in these patients. |
| |
c. |
Patients with
chest pain and normal or nonobstructive coronary angiograms are predominantly
women, and many have a prognosis that is not as benign as commonly thought (2%
risk for death or myocardial infarction [MI] at 30 days of follow-up).
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| |
d. |
Useful
therapeutic agents for symptom relief are β-blockers, angiotensin-converting
enzyme (ACE) inhibitors, and tricyclic agents. Aggressive antiatherosclerotic
therapy with statins should also be undertaken.
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5. |
Refractory
angina:
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a. |
Refers to
patients who, despite optimal medical therapy, have both angina and objective
evidence of ischemia and are not considered candidates for
revascularization. |
| |
b. |
Current U.S.
Food and Drug Administration (FDA)-approved therapies consist of enhanced
external counterpulsation (EECP), transcutaneous electrical nerve stimulation
(TENS), and invasive therapies, such as spinal cord stimulation, transmyocardial
revascularization, and percutaneous myocardial revascularization. Although some
of these therapies may improve symptoms and quality of life, they have not been
shown to decrease mortality. |
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6. |
Other: angina
caused by aortic stenosis and idiopathic hypertrophic subaortic stenosis (IHSS),
cocaine, or epinephrine-induced coronary vasoconstriction. |
