View source for Chronic stable angina assessing the pretest probability of coronary artery disease

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{{Chronic stable angina}}

{{CMG}}; '''Associate Editor-in-Chief:''' Smita Kohli, M.D.

==Overview==
Pretest probability is defined as the probability of the target disorder before the result of a diagnostic test is known.  A number of studies have emphasized the importance of pretest probability of [[coronary artery disease|coronary artery disease (CAD)]].<ref name="pmid7258092">Diamond GA, Forrester JS (1981) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=7258092 Improved interpretation of a continuous variable in diagnostic testing: probabilistic analysis of scintigraphic rest and exercise left ventricular ejection fractions for coronary disease detection.] ''Am Heart J'' 102 (2):189-95. PMID: [http://pubmed.gov/7258092 7258092]</ref> Once a thorough patient [[Chronic stable angina symptoms|history]] and [[Physical examination|physical examination]] is complete, it is important to assess the probability of underlying CAD, as this helps both the physician and the patient to determine the next step in the [[Chronic stable angina test selection guideline for the individual basis|diagnosis]] and [[Chronic stable angina treatment|treatment]]. In patients with [[Chronic stable angina definition|chronic stable angina]], the strongest predictors contributing to underlying significant [[CAD]] include: the age, gender and type of pain (typical, atypical) experienced.<ref name="pmid7258092">Diamond GA, Forrester JS (1981) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=7258092 Improved interpretation of a continuous variable in diagnostic testing: probabilistic analysis of scintigraphic rest and exercise left ventricular ejection fractions for coronary disease detection.] ''Am Heart J'' 102 (2):189-95. PMID: [http://pubmed.gov/7258092 7258092]</ref>

==Pretest Probability==
*Pretest probability is defined as the probability of the target disorder before the result of a diagnostic test is known. 
*The pretest probability is especially useful for:
:*Deciding whether it is worth proceeding with testing at all (this is referred to as the test threshold)
:*Selecting the type of diagnostic test
:*Interpreting the results of a diagnostic test
:*Choosing whether to start therapy: a) without further testing (this is referred to as the treatment threshold) or b) while awaiting further testing

==Calculating the Pretest Probability for Coronary Artery Disease==
*The first step is to categorize the nature of the chest pain or discomfort. This can be done as follows:
:*Typical angina (definite): The characteristics of typical angina include:
::# Substernal chest discomfort of characteristic quality and duration
::# The pain is provoked by exercise or emotional stress
::# The pain is relieved by rest or [[NTG]]
:*Atypical angina (probable): Meets two of the above criteria
:*Non-anginal pain: Meets one or zero of the anginal characteristics.
*Based on the ACC/AHA 2002 guidelines,<ref name="pmid12515758">Gibbons RJ, Abrams J, Chatterjee K, Daley J, Deedwania PC, Douglas JS et al. (2003) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=12515758 ACC/AHA 2002 guideline update for the management of patients with chronic stable angina--summary article: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on the Management of Patients With Chronic Stable Angina).] ''Circulation'' 107 (1):149-58.[http://content.onlinejacc.org/cgi/reprint/41/1/159.pdf] PMID: [http://pubmed.gov/12515758 12515758]</ref> the  pretest probability can be classified into:
:*Low probability: less than 10%-20%;
:*Intermediate probability: between 20%-80%;
:*High probability: more than 80%-90%.
*A quick way to assess this is shown in Table 1.<ref name="pmid17998462">Fraker TD, Fihn SD, Gibbons RJ, Abrams J, Chatterjee K, Daley J et al. (2007)[http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=17998462 2007 chronic angina focused update of the ACC/AHA 2002 Guidelines for the management of patients with chronic stable angina: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines Writing Group to develop the focused update of the 2002 Guidelines for the management of patients with chronic stable angina.] ''Circulation'' 116 (23):2762-72.[http://content.onlinejacc.org/cgi/reprint/50/23/2264.pdf] PMID: [http://pubmed.gov/17998462 17998462]</ref><ref name="pmid15238371">Snow V, Barry P, Fihn SD, Gibbons RJ, Owens DK, Williams SV et al. (2004) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=15238371 Evaluation of primary care patients with chronic stable angina: guidelines from the American College of Physicians.] ''Ann Intern Med'' 141 (1):57-64. PMID: [http://pubmed.gov/15238371 15238371]</ref><ref name="pmid7055887">Diamond GA, Forrester JS (1982) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=7055887 Probability of CAD.] ''Circulation'' 65 (3):641-2. PMID: [http://pubmed.gov/7055887 7055887]</ref>

<center>'''Table 1: Pretest Probability of Coronary Artery Disease'''

{| border="1" align="center" style="background:LightSkyBlue"
|-
| bgcolor="CornFlowerBlue" |'''Age''' (yrs)
| bgcolor="CornFlowerBlue" |'''Gender'''
| bgcolor="CornFlowerBlue" |'''Non-anginal pain'''
| bgcolor="CornFlowerBlue" |'''Atypical angina'''
| bgcolor="CornFlowerBlue" |'''Typical angina'''
|-
| 30-39
| Men
| Low
| Intermediate
| Intermediate
|-
| 
| Women
| Low
| Low
| Intermediate
|-
| 40-49
| Men
| Intermediate
| Intermediate
| High
|-
| 
| Women
| Low
| Low
| Intermediate
|-
| 50-59
| Men
| Intermediate
| Intermediate
| High
|-
| 
| Women
| Low
| Intermediate
| Intermediate
|-
| 60-69
| Men
| Intermediate
| Intermediate
| High
|-
|
| Women
| Intermediate
| Intermediate
| High
|}</center>

==References==
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