INTERCHEST Clinical Prediction Rule for Chest Pain in Primary Care
Rules out coronary artery disease (CAD) in primary care patients with chest pain.
Do not use in an emergency setting.
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When evaluating patients with chest pain in primary care, INTERCHEST scores ≤1 mean the chest pain is highly unlikely to be due to unstable CAD (NPV 98%), and further outpatient evaluation is generally safe and appropriate.
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A primary care patient with an INTERCHEST score of ≤1 generally does not need urgent evaluation of chest pain (unless there is clear evidence of clinical instability), and further evaluation may be done through non-urgent outpatient follow up.
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A primary care patient with an INTERCHEST score ≥2 does not necessarily have unstable CAD, but should have further testing done more urgently.
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For any primary care patient with chest pain, clinical stability can quickly be determined by evaluating the ABCs (airway, breathing, and circulation).
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A patient who shows no signs of respiratory distress and has appropriate vital signs is unlikely to be acutely unstable and can be further evaluated the office with appropriately targeted history, physical examination, and testing.
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If there is a readily apparent cause of chest pain other than CAD (e.g. trauma, infection), attention should be directed to these causes.
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If there are clearly anginal equivalent symptoms (e.g. jaw pain, dyspnea on exertion, arm pain), or if there are ischemic changes on the ECG, then the INTERCHEST score does not apply and urgent inpatient admission is warranted.
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A patient with undiagnosed chest pain and a low risk INTERCHEST score (≤1) can have further testing, including chest x-ray and stress testing, electively as an outpatient.
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A patient with a higher risk INTERCHEST score (≥2) does not necessarily have unstable CAD, but since unstable CAD cannot be excluded if the INTERCHEST score is ≥3, such patients generally warrant more urgent evaluation or inpatient admission.
No decision rule should trump clinical gestalt, and any patient with chest pain who is clinically unstable (respiratory distress or abnormal vital signs) warrants urgent or emergency inpatient admission.