Presenting Features in ACS: What's Useful and What's Not?

The Study

The Value of Symptoms and Signs in the Emergent Diagnosis of Acute Coronary Syndromes

Body R, Carley S, Wibberley C, McDowell G, Ferguson J, Mackway-Jones K
Resuscitation. 2010;81:281-286

Study Summary

The investigators prospectively evaluated 796 patients presenting to the ED with suspected cardiac chest pain and recorded diverse clinical features, including aspects of patient histories and examinations. All patients were followed up for the diagnosis of acute myocardial infarction (MI) and the occurrence of adverse cardiac events (death, MI, need for urgent revascularization) within 6 months.

Acute MI was diagnosed in 148 (18.6%) of the patients. After adjustment for age and sex, presenting features that made acute MI more likely included pain radiating to the right arm or shoulder (odds ratio [OR], 2.23) or to both arms or shoulders (OR, 2.69), vomiting (OR, 3.50), central location of chest pain (OR, 3.29), and observed diaphoresis (OR, 5.18). Reported diaphoresis also predicted acute MI, but not as strongly as when observed by the clinician. Other nonhistorical factors that predicted acute MI were no surprise: ischemic findings on ECG and hypotension. These findings were all noted to be predictive of 6-month adverse outcome as well.

Symptoms that were not found to be predictive of acute MI or adverse outcome at 6 months included pain radiating to the jaw, neck, or throat or to the left arm or shoulder left-sided pain; dyspnea; nausea; pain at rest; and pain described as heavy or pressure, tight or squeezing, or similar to prior episodes of ischemia. Anecdotally, however, this is probably no surprise to experienced acute care physicians. We've all seen countless patients presenting with "classic" features that rule out acute MI and ACS. As Body and colleagues suggest, the presence or absence of many of these classic symptoms "gives us little capacity to discriminate between patient with and without acute MI in the ED."

Viewpoint

Body and colleagues' findings in this study, performed in England in a single inner-city ED, might not be worthy of a lengthy discussion if this were an isolated finding. However, there are 2 other important publications that support their findings -- publications with which all physicians who manage patients with chest pain should be familiar.

The first of these was by Panju and colleagues and appeared in 1998 in "The Rational Clinical Examination" section of JAMA.^[2]The authors reviewed the medical literature through the mid-1990s and assigned likelihood ratios (LRs) to various features that increase and decrease the chance that acute chest pain rules in or rules out acute MI. They found that the factors most likely to increase the likelihood of acute MI were positive findings on ECG (LR, 5.7-53.9), presence of a third heart sound (LR, 3.2), hypotension (LR, 3.1), and pain radiating to both the left and right arms simultaneously (LR, 7.1).

Unlike Body and colleagues, Panju and colleagues found that pain radiating to the left arm alone did slightly increase the likelihood of acute MI (LR, 2.3), but similar to Body and colleagues, they found that concern is greater with pain radiating to the right arm alone (LR, 2.9). Other concerning features included nausea and vomiting (LR, 1.9) and diaphoresis (LR, 2.0).

Panju and colleagues also identified several features of acute chest pain that decreased the probability of MI: pleuritic (LR, 0.2), sharp or stabbing (LR, 0.3), positional (LR, 0.3), and reproduced by palpation (LR, 0.2-0.4). Of note, although the LRs reflect a lesser chance of acute MI, none of these features eliminate the risk.

A more recent study by Swap and Nagurney^[1] reviewed the literature through 2005 to assess features that might predict ACS in patients presenting with chest pain. They found that the features that increased the likelihood of acute MI were pain radiating to the right arm or shoulder (LR, 4.7), pain radiating to both arms or shoulders (LR, 4.1), association between pain and exertion (LR, 2.4), pain radiating to the left arm (LR, 2.3), diaphoresis (LR, 2.0), and pain described as worse than previous angina or similar to previous MI (LR, 1.8). A surprise again: Pain described as pressure was not very predictive of ACS (LR, 1.3).

Swap and Nagurney's findings corroborated those of Panju and colleagues in that several features of acute chest pain decreased the probability of ACS, although none eliminated the risk: pleuritic (LR, 0.2), positional (LR, 0.3), sharp (LR, 0.3), reproduced by palpation (LR, 0.3), and not associated with exertion (LR, 0.8).

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