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Three Part Question

In [a patient with chest pain of uncertain aetiology] is [the use of antacids/alginates] useful for [differentiating between cardiac and gastro-oesophogeal causes]?

Clinical Scenario

A 57 year old man presents with a one hour history of central chest pain the character of which he cannot describe. There is no radiation but there is mild sweating and subjective shortness of breath. He has a history of smoking, hypertension, angina and a hiatus hernia; the pain came on after a curry. He has a normal ECG on admission and an unremarkable examination. You cannot decide whether this is cardiac or oesophageal in origin and wonder whether a single dose of antacid might relieve his pain and therefore clarify the diagnosis.

Search Strategy

Medline 1966-12/02 using the OVID interface.
[exp chest pain OR exp angina pectoris OR exp angina, unstable OR exp coronary disease OR exp myocardial infarction OR chest pain.af OR angina.af OR coronary.af OR myocardial.af OR cardiac.af OR myocard$.af] AND [ exp alginates OR exp antacids OR algin$,af OR antacid.af OR antacids.af OR gaviscon.af OR algicon.af OR gastrocote.af OR peptac.af OR topal.af]} LIMIT to human AND English language.

Search Outcome

Altogether 374 papers were found only two of which directly addressed the three part question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Henderson RD et al, 1978, Canada	100 patients with typical reflux pain. 43 with atypical pain and investigations showing oesophageal disease and normal coronary arteries	Clinical trial	Relief of pain with antacids	95% relief in typical reflux group. 18% atypical pain group	Small numbers No blinding Statistical significance not assessed Antacid type/dosage not described
Simpson FG et al, 1984, UK	46 patients with proven MI	Survey	Pain felt to be indigestion	21/46 (45%)	Small numbers Statistical significance not assessed
			Relief of pain in those that had taken antacids	5/17 (29%)

Comment(s)

Both studies are small, however in the Henderson paper if the 95% confidence intervals are calculated (81.5-100% typical, 9-30.2% atypical) there is a distinct difference between the two groups despite all the patients having normal ETTs and angiography. A further paper by Davies et al (1) has shown that the instillation of acid into the stomach decreases the angina threshold on exercise testing. The above tests would suggest that reflux affects angina and vice versa, the vagus nerve has been suggested as the common link between the two.

Clinical Bottom Line

Antacids are useful in the relief of pain that is clearly oesohageal in origin but the effect is insufficiemtly specific to be of value in aiding diagnosis.

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

1. Henderson RD, Wigle ED, Sample K, et al. Atypical chest pain of cardiac and esophageal origin. Chest 1978;73(1):24-7.
2. Simpson FG, Kay J, Aber CP. Chest Pain- indigestion or impending heart attack. Postgraduate Medical Journal 1984;60(703):338-340.
3. Davies HA, Rush EM, Lewis MJ, et al. Oesophageal stimulation lowers external angina threshold. Lancet 1985;1(8436):1011-1014.