Vancouver Chest Pain Rule

Clinical background

In the emergency department, chest pain of suspected ischaemic origin is one of the commonest and most resource-intensive management problems. Most of these patients do not have an acute coronary syndrome (ACS), but the consequence of missing an infarction is serious enough that traditional practice has often meant prolonged observation, serial blood tests and sometimes provocative testing of patients who in retrospect were low risk all along. The Vancouver Chest Pain Rule was developed precisely to identify a subgroup who can be discharged safely after only 2 hours of observation, without further provocative testing or admission. The tool is therefore a rule-out instrument, not a diagnostic test for confirming ACS.

Applying the Vancouver Chest Pain Rule

Unlike score-based instruments such as HEART or TIMI, the Vancouver Chest Pain Rule is a decision rule with two alternative routes to safe early discharge. No total score is calculated. The patient is judged safe for early discharge if either route A or route B is satisfied and all the mandatory conditions are met:

Route A (young, low-risk profile):

• Age <40 years
• No known coronary artery disease (previous myocardial infarction, PCI, CABG or angina)
• The pain does not radiate to the neck, jaw or either arm
• No sweating observed at the onset
• The pain is not part of an accelerating or worsening pattern
• No ischaemic ECG changes (new, not previously known)
• Initial (0 h) troponin below the 99th percentile
• 2-hour troponin below the 99th percentile

Route B (pain reproducible on palpation):

• The chest pain is fully reproducible on palpation
• No ischaemic ECG changes (new, not previously known)
• Initial (0 h) troponin below the 99th percentile
• 2-hour troponin below the 99th percentile

The rule can be stated formally as:

$$\text{Safe for early discharge} = \left(\text{Route A} \lor \text{Route B}\right) \land \neg\text{Ischaemic ECG changes} \land \neg\text{Troponin rise}$${0h} \land \neg\text{Troponin rise}{2h}

where route A requires age $<40$, no known coronary artery disease, no radiation, no sweating and a non-worsening pattern, and route B requires pain fully reproducible on palpation.

The derivation study was carried out at St. Paul's Hospital in Vancouver, Canada, as a prospective cohort study [1]. In total 769 patients $\geq 25$ years with chest pain of suspected ischaemic origin were included. At 30 days, 77 patients (10.0%) had acute myocardial infarction and 88 (11.4%) definite unstable angina, giving 21.4% with ACS in total. The original rule used CK-MB as the biomarker and achieved a sensitivity of 98.8% and a specificity of 32.5%. The aim was to miss fewer than 2% of ACS patients and to allow discharge within 2 to 3 hours for at least 30% of patients without ACS.

The version of the rule reproduced by this calculator is the modified one using troponin as the sole biomarker instead of CK-MB. This modification has been validated in several independent cohorts and is the one that has entered clinical practice [2, 3].

Interpretation in practice

The rule has only two outcomes: the patient either meets the criteria for safe early discharge or does not. There is no intermediate category.

It is important to note that a patient who does not meet the rule is not thereby at high risk of ACS. The rule is conservative: it prioritises sensitivity over specificity, and many patients who do not meet the criteria will nonetheless prove not to have ACS. The decision on further investigation, admission or provocative testing in these patients is made on the usual clinical grounds.

Validation and performance

The modified Vancouver Chest Pain Rule with troponin as the sole biomarker has been validated in several independent cohorts, with varying results.

Internal validation within the same research group. Scheuermeyer et al. carried out a derivation and validation study in two blocks (2000 to 2003 and 2006) with a total of 1,669 patients at the same Canadian emergency department [4]. In the validation cohort (906 patients, 13.1% ACS), sensitivity was 99.2% (95% CI 95.4 to 100.0) and specificity 23.4% (95% CI 20.6 to 26.5). This version used an age limit of 50 years rather than 40 years, which differs from the calculator's specification.

External validation in Australia and New Zealand. Greenslade et al. evaluated the rule in a prospective cohort of 1,635 patients at two emergency departments [2]. Here 33% were classified as low risk, but 5.6% of these had ACS at 30 days. Sensitivity was 91.0% (95% CI 85.7 to 93.6), which the authors judged insufficient for safe early discharge. In a follow-up analysis by the same group, in which the rule was instead applied with high-sensitivity troponin, performance improved: 13.0% of patients were classified as low risk, and only 1.4% of these had ACS [3]. Sensitivity rose to 99.1% (95% CI 97.4 to 99.7) and the negative predictive value to 98.6% (95% CI 95.9 to 99.5). Specificity was, however, low at 16.1%.

Comparative studies. In a study by Greenslade et al., five accelerated diagnostic pathways were compared using a new high-sensitivity troponin I assay in 1,811 patients [5]. The Vancouver Chest Pain Rule achieved 100% sensitivity for acute myocardial infarction (95% CI 96.2 to 100) and 98.6% for ACS (95% CI 94.9 to 99.8), but classified only 28.2% as low risk. Compared with the HEART model (49.8%), EDACS (62.5%) and m-ADAPT (64.3%), the Vancouver rule was therefore more conservative and discharged fewer patients, but with higher sensitivity. In a British comparative study by Carlton et al. of 959 patients, the Vancouver rule did not achieve the predefined target of a $\geq 99.5$ negative predictive value for acute myocardial infarction with a single troponin value at presentation [6].

Systematic review. A meta-analysis by Hill et al. comprising 37 studies and 404,566 patients showed that accelerated diagnostic protocols for chest pain in the emergency department generally reduce the length of stay by an average of just over an hour, reduce the proportion of patients admitted (pooled RR 0.84, 95% CI 0.79 to 0.89) and do not increase the rate of major cardiac events at 30 days (pooled RR 0.95, 95% CI 0.86 to 1.04) [7]. This review covers several different protocols, not the Vancouver Chest Pain Rule alone, but it supports the general view that accelerated diagnostic pathways are safe and effective.

In summary, the rule performs best when combined with high-sensitivity troponin assays. With conventional troponin assays, sensitivity in external cohorts has been lower than in the derivation study, and the rule has then not been considered reliable enough for safe early discharge.

Limitations

The rule applies only to patients with suspected ischaemic chest pain in whom ACS is not already confirmed. The following patients are not covered:

• Patients with ST elevation or another obvious ECG change directly indicating ACS. These patients should be managed according to current ACS guidelines and not assessed with the rule.
• Patients with known coronary artery disease are not covered by route A. Route B could in theory be applied, but in practice these patients should be managed conservatively.
• Patients with atypical symptoms in whom chest pain is not the dominant complaint. The derivation cohort consisted of patients with chest pain as the primary symptom.
• Patients under 25 years were not included in the derivation cohort, and the rule has not been validated in this group.

The commonest errors in applying the rule are:

1. Using the rule as a diagnostic test to confirm ACS in patients who do not meet the low-risk criteria. A negative result excludes ACS with high probability, but failure to satisfy the rule does not mean the patient has ACS.
2. Disregarding ischaemic ECG changes or a troponin rise because the patient otherwise meets the low-risk criteria. Any ischaemic ECG change or troponin rise overrides both low-risk routes, whatever the rest of the profile.
3. Applying the rule with conventional troponin assays without recognising that sensitivity may then be insufficient. Performance is considerably better with high-sensitivity troponin assays.
4. Failing to arrange outpatient follow-up for patients who are discharged. Even though the risk of ACS is very low, follow-up is recommended for further risk stratification of coronary artery disease.

References

1. Christenson J et al. A clinical prediction rule for early discharge of patients with chest pain. Ann Emerg Med 2006. PMID: 16387209
2. Greenslade JH et al. Validation of the Vancouver Chest Pain Rule using troponin as the only biomarker: a prospective cohort study. Am J Emerg Med 2013. PMID: 23702078
3. Cullen L et al. The new Vancouver Chest Pain Rule using troponin as the only biomarker: an external validation study. Am J Emerg Med 2014. PMID: 24238485
4. Scheuermeyer FX et al. Development and validation of a prediction rule for early discharge of low-risk emergency department patients with potential ischemic chest pain. CJEM 2014. PMID: 24626115
5. Greenslade JH et al. Diagnostic Accuracy of a New High-Sensitivity Troponin I Assay and Five Accelerated Diagnostic Pathways for Ruling Out Acute Myocardial Infarction and Acute Coronary Syndrome. Ann Emerg Med 2018. PMID: 29248334
6. Carlton EW et al. Identifying Patients Suitable for Discharge After a Single-Presentation High-Sensitivity Troponin Result: A Comparison of Five Established Risk Scores and Two High-Sensitivity Assays. Ann Emerg Med 2015. PMID: 26260100
7. Hill J et al. Effectiveness of accelerated diagnostic protocols for reducing emergency department length of stay in patients presenting with chest pain: A systematic review and meta-analysis. PLoS One 2024. PMID: 39436875