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Three Part Question

In [patients with suspected acute myocardial ischaemia] does [chest pain lasting longer than 48 hours] enable [accurate exclusion of acute coronary syndromes]?

Clinical Scenario

A 42-year-old man arrives at the Emergency Department with four days of chest pain. He has no cardiac risk factors including diabetes, tobacco use, hypertension, abnormal lipids or family history of coronary artery disease (CAD) and his EKG demonstrates equivocal ST elevations in anterior leads. He wants to go home and states he is “only here because my wife made me.” You wonder if more than 48 hours of chest pain is sufficiently reliable to exclude ACS in a patient with no other risk factors and an equivocal EKG.

Search Strategy

Medline 1950-6/2009 using the OVID interface

*exp Chest Pain/mo, et, di and exp Acute Coronary Syndrome/
*exp Myocardial Infarction/ and exp Medical History Taking/
LIMIT to English language

Search Outcome

258 papers were found. Two relevant systematic reviews were submitted in 2003 and 2008 were found. Since 2008 no relevant papers were found.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Hess et al. 2008 USA	2 articles examined the diagnosis of ACS with a) prolonged chest pain in past 15 days in 321 patients b) ≥ 2 anginal events in past 24 hours in 1236 patients	Systematic review of 674 articles (8 deemed high quality) dating 1950-2007.	a) Recurrent ischemia, death, heart failure b) All-cause mortality, AMI, re-vascularization, unstable angina	Negative Likelihood ratio & 95% confidence intervals for presence of ACS using entire prediction guide a) 0.05 (0.01-0.22) b) 0.12 (0.04-0.36)	-evaluation in the systematic review was based on a multi-part prediction guide a) excluded chest pain more than 12 hours in duration b) number of events rather than duration
Chun & McGee 2003 USA	2 articles examined the duration of chest pain in the diagnosis of CAD and MI including 130 & 278 patients respectively.	Systematic review of 270 articles (64 deemed relevant) dating 1966-2003.	CAD defined as cardiac catheterization revealing substantial stenosis of any major epicardial vessel. MI defined as elevated cardiac isoenzyme levels, diagnostic EKG changes or both.	Likelihood ratio & 95% confidence intervals for presence of: >30 minutes of CP in diagnosis of CAD 0.1 (0.0-0.9) >60 minutes of CP in diagnosis of MI 1.1 (0.9-1.3)	-Duration of chest pain was limited to >30 or 60 minutes instead of multiple days

Comment(s)

Two good systematic reviews exist looking at bedside diagnosis of coronary artery disease including myocardial infarction and diagnostic accuracy of clinical prediction rules in ACS. However, there were no studies specifically evaluating duration of chest pain longer than one hour let alone multiple days. Clinical prediction guides exist using multiple history, physical and laboratory data points but many, if not all, require a definitively normal EKG.

Clinical Bottom Line

No good evidence exists to evaluate the accuracy of ruling out ACS in a patient with chest pain lasting over 60 minutes.

References

1. Hess EP, Thiruganasambandamoorthy V, Wells GA, Erwin P, Jaffe AS, Hollander HE, Montori VM, Stiell IG Diagnostic accuracy of clinical prediction rules to exclude acute coronary syndrome in the emergency department setting: a systematic review CJEM 2008 Jul; 10(4):373-82.
2. Kita Chun A, McGee SR Bedside diagnosis of coronary artery disease: a systematic review Am J Med 2004;117:334 –343