June 13, 2022

ACEP22: Appropriate Emergency Department Utilization of CT for Pulmonary Embolism

The Pulmonary Embolism measure is slowly becoming one of the most utilized measures in the ACEP registry. Pulmonary embolism is the third most common cardiovascular disease, often missed. This measure aims to reduce the inappropriate ordering of CTPA for pulmonary embolism based on pre-test probability estimation. This measure does not require the utilization of a structured clinical prediction rule such as the Wells Score or Geneva Score. However, the measure aims to improve efficiency by guiding clinical practice towards the use of the PERC rule or d-dimer testing rather than immediate CTPA in low-probability patients, as indicated. In addition to imaging efficiency, the overuse of CTPA in ED patients with suspected pulmonary embolism has tangible implications for patient safety.

At-a-glance details of the measure: 

Formal description: Percentage of emergency department visits during which patients aged 18 years and older had a CT pulmonary angiogram (CTPA) ordered by an emergency care provider, regardless of discharge disposition, with either moderate or high pre-test clinical probability for pulmonary embolism OR positive result or elevated D-dimer level

Domain: Efficiency/Cost Reduction 

Type: Process (as opposed to Outcome or Efficiency measure)

Patients with a high pre-test probability for PE are recommended to undergo pulmonary imaging, primarily computed tomographic pulmonary arteriogram (CTPA). It is recommended that patients with a moderate pre-test probability proceed with D-dimer testing.  If the D-dimer is normal, then no further testing (unless clinical probability is high) is necessary, and PE is ruled out. If the D-dimer is elevated, then further testing (CTPA) is necessary. The D-dimer is considered abnormal in patients < 50 years of age if it is greater than 500 ng/mL by an enzyme-linked immunosorbent assay [ELISA]. 1

If the pre-test probability is low or intermediate, D-dimer testing should be used in outpatient and emergency department settings (Class I). (ESC, 2014)

Low pre-test probability and a negative D-dimer test excludes acute PE (Class I). (ESC, 2014)

Let’s talk about the measure in discussion.

The measure includes all adult patients that had a CTPA ordered, excluding pregnant females, followed by a reverse analysis to look for the indication justifying the order.

Let’s look at the Denominator for the measure:

All adults with a CTPA ordered. Now some hospitals will utilize a CT chest contrast or CT Chest based on the availability to detect PE. Ensure you are closely working with your CEDR account managers to point out such nuances.

Once the Denominator population is decided, all female patients with an active pregnancy are excluded. Again, it might seem straightforward, but where in the chart this information is collected from makes a big difference. If a previous pregnancy is captured from the problem list, it will exclude unnecessary cases and shrink the denominator population.

The biggest challenge, however, for this measure is capturing the Numerator.

Pre-Test Probability diagnosis is almost always in free text and is difficult to capture. One easy solution is to guide the EPs to add it to the Encounter diagnosis or work with the EHR Vendor and include it as a discrete field in the drop-down menu to indicate the CTPA order.

The other area of challenge during numerator calculation is the D-dimer result. The easiest way to capture the elevated D-dimer is with the help of a flag which marks it as elevated. The challenge arises with the variation in the D-dimer units received, making it difficult to assign a cut-off.

However straightforward a measure seems, it has its own nuances, whether small or big, when it is ready for implementation. But the good part is that ACEP has a great team of experts with years of experience to guide you with collecting measure-specific data elements and help you get a higher performance.


  1. https://mypulmonaryembolism.com/approach-to-a-patient-with-suspected-pulmonary-embolism/#:~:text=Scores%20of%203%2D6%20points,66.7%25%20risk%20of%20PE