Stable Angina
last authored: Jan 2010, David LaPierre
last reviewed:
Introduction
Angina (Latin: strangling) represents insufficent blood flow to the heart, usually occurring due to coronary artery atherosclerosis and during periods of exertion.
The Case of...
a simple case introducing clincial presentation and calling for a differential diagnosis to get students thinking.
Causes and Risk Factors
Angina affects almost four percent of the population. Causes include:
- coronary artery disease
- vasospasm
- infections
Aggravating factors include:
- anemia
- obesity
- hperthyroidism
- hypertension
- infection
- heart failure
- hypoxemia
Pathophysiology
Angina is the mildest form of ischemic heart disease, representing an imbalance between oxygen supply and demand. Under resting conditions, myocardial oxygen extraction is near maximal, and any further strain causes symptoms.
Exercise or stress causes an increase in sympathetic activity, leading to increased heart rate and contractility, and thereby myocardial oxygen requirements.
In the majority of people, angina is due to limitations in myocardial oxygen due to atherosclerosis in one or more coronary arteries.
In cold weather, vasoconstriction can decrease exercise tolerance.
Vessel autoregulation during ischemia
adenosine, increased[K]out , and decreased pH all lead to vasodiation in ischemic areas
Signs and Symptoms
- history
- physical exam
History
Angina is characterized by substernal pain or tightness, often decribed as constricting, squeezing, choking, or knifelike, with typical duration.
It can also be accompanied by shortness of breath or a sensation of choking.
Angina is uncomfortable but usually temporary. It can be provoked by exercise, emotional stress, cold weather, or eating a heavy meal, and removing these factors soon brings relief.
stable - hasn't changed for at least 2 months
CCS functional classification of angina:
- class I: ordinary activity does not cause angina
- class II: slight limitation
- class III: marked limitation
- class IV: inability to perform any activty without marked discomfort.
Physical Exam
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
Diagnostic Imaging
A stress test can be helpful to determine presence and extent of ischemia during exertion.
Differential Diagnosis
Treatments
Goals of treatment are to:
- decrease frequency and severity of symptoms
- prevent or slow atherosclerotic progression
- prolong life
- prevent future cardiac events
Lifestyle and risk factor modification
Improve diet and exercise to
- quitting smoking
- maintaining a healthy weight
- control dyslipidemia, diebetes mellitus, and hypertension
Statins can be used to lower LDL-C, stablize atherosclerotic plaques, and have anti-anflammatory and anti-thrombotic plaques
Symptom relief
Relief of symptoms and improvement in exercise capacity is acheived by improving oxygen supply or decreasing oxygen demand.
- nitroglycerin
- beta blockers
- if previous MI
- aim for resting HR of 50-60 bpm, and blunted heart response to exercise (100 bpm)
- avoid in people with asthma
- calcium channel blockers
If monotherapy does not work, additional drugs can be used.
If conduction system disease - amlodipine, nifedipine, nitroglycerin
SV arrhythmias - beta blocker, diltiazem, verapamil
Secondary prevention
Aspirin should be used daily, indefinitely, to reduce sudden death and MI. Clopidogrel should be used if intolerance to ASA.
Coronary artery bypass graft (CABG)
- left main disease
- significant proximal stenosis of the three main coronary arteries
- significant stenosis of 2 major coronary arteries, including proximal LAD
- presence of LV systlic dysfunction
- multi-vessel CAD in people with diabetes
Coronary angiography can be used if people have disabling angina or poor response to therapy, evidence of heart failure, people with serious ventricular arrhythmias, others.
Consequences and Course
The Case of...
Case #2 - a small story wrapping it all up and asking especially about management.
Additional Resources
any good free online resources for further reading.
Topic Development
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