Clinical score plus point-of-care troponin rules out acute coronary syndrome in general practice

Design

Cluster-randomised diagnostic trial, 2:1

Population

827 primary care patients with acute chest pain (740 intervention)

Primary outcome

Diagnostic accuracy for acute coronary syndrome and myocardial infarction

Effect

ACS sensitivity 98.3% (95% CI 90.8-100), NPV 99.7%; specificity 49.1%

POB-HELP was a cluster-randomised diagnostic trial in Dutch general practices. In 740 patients with acute chest pain, GPs applied a decision rule combining the Marburg Heart Score, a short clinical score, with a point-of-care high-sensitivity troponin I test; 87 patients in control practices received usual care.

The rule missed one acute coronary syndrome: sensitivity 98.3% (95% CI 90.8 to 100) and negative predictive value 99.7%. It missed no myocardial infarction. Specificity was about 49%, so roughly half of patients without a coronary syndrome were still flagged, and referral rates did not differ significantly from usual care (54.6% vs 47.1%).

The value is in the negatives: a patient who is low on the score and has a normal troponin can be managed in the practice with confidence. It does not reduce referrals overall. Point-of-care high-sensitivity troponin is not widely available in Indian primary care, but where it is, this combination is a safer rule-out than either clinical judgement or a single test alone. Timing of the test relative to symptom onset still matters.

• Consider combining a validated clinical score with point-of-care high-sensitivity troponin for chest pain in primary care.
• A low score with a normal troponin had a negative predictive value of 99.7% for acute coronary syndrome.
• A positive rule is not a diagnosis; most flagged patients did not have a coronary syndrome.
• Refer immediately anyone with ongoing pain, ECG changes or haemodynamic compromise, whatever the score.
• Check how long after symptom onset the troponin was taken.

Why it matters

It gives family physicians a tested way to keep low-risk chest pain in the practice safely.

Don't overread it

Referrals did not fall, and the confidence interval for sensitivity reaches down to about 91%.

The statistics, in plain English

Sensitivity of 98.3% rests on about 60 coronary syndromes, so its lower confidence limit is 90.8%: the rule could miss up to about 1 in 11 in the worst case. The negative predictive value is high mainly because most patients with chest pain in primary care do not have a coronary syndrome.

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