Edaculator the ED ACS Calculator

Acute coronary syndrome risk score calculator based on the EDACS study

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The Edaculator

This calculator is based on the model presented in the EDACS study as described below. It is used to calculate a risk score, which must then be interpreted in the context of the accelerated diagnostic protocol (EDACS-ADP) considering the pertinent inclusion/exclusion factors, ECG findings and troponin levels.

The Edaculator has been developed by Michael Edmonds, an ACEM advanced trainee at the Royal Adelaide Hospital. As well as calculating EDACS scores, the Edaculator is being integrated into a low-risk chest pain discharge pathway within our emergency department, customised to collect patient data for validation of this score and comparison to other systems.

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The EDACS Study

Than, M., Flaws, D., Sanders, S., Doust, J., Glasziou, P., Kline, J., Aldous, S., Troughton, R., Reid, C., Parsonage, W. A., Frampton, C., Greenslade, J. H., Deely, J. M., Hess, E., Sadiq, A. B., Singleton, R., Shopland, R., Vercoe, L., Woolhouse-Williams, M., Ardagh, M., Bossuyt, P., Bannister, L. and Cullen, L. (2014), Development and validation of the Emergency Department Assessment of Chest pain Score and 2 h accelerated diagnostic protocol. Emergency Medicine Australasia, 26: 34–44. doi: 10.1111/1742-6723.12164

This model was derived from data prospectively collected for patients aged 18 years or over, with at least 5 min of symptoms consistent with an acute coronary syndrome (i.e. acute chest, epigastric, neck, jaw or arm pain; or discomfort or pressure without an apparent non-cardiac source), such that the attending physician planned to perform further investigations for this potential diagnosis. Patients were recruited from 2 urban emergency departments (Brisbane, Australia and Christchurch, New Zealand).

Patients were followed up for 30 days (100% follow up), and outcomes of major adverse cardiac events (MACE) were recorded:

  • ST-elevation or non-ST-elevation myocardial infarction
  • Emergency revascularisation
  • Ventricular arrhythmia
  • Cardiac arrest
  • Cardiogenic shock
  • High atrio-ventricular block
  • Death from cardiovascular causes

Derivation (n=1974)

Predictive factors were identified from a list of 37 possible variables through univariate analysis and logistic regression to develop a predictive score. Variables were collected using patient report so it is reproducible in the absence of previous medical records. This score was then refined to increase clinical validity and sensibility through consolidation of age groups and inclusion of traditional cardiac risk factors. The modified score was shown to perform as well as the original score.

Findings on ECG and troponin testing do not form part of the EDACS score to allow for future advancements in these areas. These aspects are incorporated in the interpretation of the risk score using the EDACS-ADP. A cut-off of 16 was the optimal score to maintain sensitivity near 99% and maximise specificity.

Validation (n=608)

The EDACS and EDACS-ADP were tested on a separate prospectively recruited validation cohort demonstrating similar sensitivity (100% [94.2 – 100.0]; no MACE in low risk group) and improved specificity (59% [54.6 – 63.2]). Combining the risk score with troponin and ECG results, 51.3% of the participants recruited were classified as low risk of MACE within 30 days and eligible for discharge at 2 h.


The authors suggest:

“Using the new ADP, more patients could be safely discharged early to outpatient follow-up investigation (or proceed more quickly to further inpatient testing). The ADP has potential to shorten hospital length of stay in a larger proportion of patients than reported previously. It could also make a significant impact in reducing ED overcrowding at minimal cost to the health systems where it is deployed.
The new risk score (EDACS) is flexible in any clinical setting. Clinicians can modify the score cut-off and combine it with any biomarker tests and ECG technology available now or in the future. The good correlation between EDACS and prevalence of MACE in both cohorts suggest that the score might be useful in identifying patients who are at higher risk, need additional investigations or require telemetry.”

It is important to note that this EDACS-ADP has not been validated in other settings or using different cut-off scores.

Interpreting the EDACS Risk Score

In this study, an EDACS score of <16 is defined as "Low Risk" when interpreted with ECG and troponin findings in the EDACS-ADP. The EDACS-ADP is suggested to safely identify patients presenting to the ED with possible cardiac chest pain as having low risk of short-term MACE. These patients would be suitable for early discharge to outpatient investigation or expedited inpatient tests. This does not exclude the diagnosis of ACS or ischaemic heart disease.

EDACS < 16

This score qualifies for the low risk EDACS-ADP when combined with no new ischaemia on ECG and negative troponin levels at presentation and at 2 hours.

Probability of MACE within 30 days is <1% in this group, according to this study. This group of patients may be safe for discharge to early outpatient follow-up investigation or early inpatient testing, as per local policy.

Exceptions: Patients with an EDACS score of <16 with ECG changes or positive troponin should enter the not low risk EDACS-ADP pathway. In addition, patients with an unstable presentation (abnormal vital signs, ongoing pain or pain in a crescendo pattern) should be included in the not low risk EDACS-ADP.

EDACS ≥ 16

An EDACS score of ≥16, unstable presentation, new ischaemic changes on ECG or a positive troponin, places the patient in the not low risk EDACS-ADP group.

The incidence of MACE is >1% in this group (and increases, correlated with EDACS score). This group is recommended to proceed with usual care, further observation and delayed troponin per local policy.


The Edaculator is made available, as is, for educational purposes. Interpretation of the EDACS risk score should be undertaken by a qualified physician, taking into account the individual patient's clinical scenario.

If you are having chest pain, please seek immediate medical attention.