years_pe_algorithm: YEARS Algorithm for Pulmonary Embolism (PE)

In cliot: Clinical Indices and Outcomes Tools

YEARS Algorithm for Pulmonary Embolism (PE)

Description

Implements the YEARS algorithm to rule out pulmonary embolism in hemodynamically stable patients. This algorithm uses three clinical criteria combined with D-dimer levels to adjust the D-dimer threshold for ruling out PE, potentially reducing the need for CT pulmonary angiography (CTPA).

Usage

years_pe_algorithm(clinical_signs_dvt, hemoptysis, pe_most_likely,
                   d_dimer_level, d_dimer_units = "ng/mL")

Arguments

clinical_signs_dvt	Numeric (0 or 1). Clinical signs of deep vein thrombosis (e.g., swelling, edema). (1 = Yes).
hemoptysis	Numeric (0 or 1). Presence of hemoptysis. (1 = Yes).
pe_most_likely	Numeric (0 or 1). Is Pulmonary Embolism the most likely diagnosis? (1 = Yes).
d_dimer_level	Numeric. D-dimer level. Assumed to be in Fibrinogen Equivalent Units (FEU).
d_dimer_units	String. Units for D-dimer input. "ng/mL" (default) or "ug/mL" (or "mg/L").

Details

The algorithm logic is as follows:

• If 0 YEARS criteria are present: PE is ruled out if D-dimer < 1000 ng/mL.

• If >= 1 YEARS criteria are present: PE is ruled out if D-dimer < 500 ng/mL.

If the D-dimer level is above the specific threshold, CTPA is indicated.

Value

A list containing:

Result	"PE Ruled Out" or "CTPA Indicated".
YEARS_Items_Met	The count of positive clinical criteria (0-3).
D_Dimer_Threshold_Used	The specific D-dimer cutoff used for the evaluation (500 or 1000).

References

van der Hulle T, Cheung WY, Kooij S, et al. Simplified diagnostic management of suspected pulmonary embolism (the YEARS study): a prospective, multicentre, cohort study. Lancet. 2017;390(10091):289-297. doi:10.1016/S0140-6736(17)30885-1

Examples

# Example 1: 0 Criteria, High D-dimer (Rule Out due to high threshold)
# No signs, No hemoptysis, PE not most likely, D-dimer 800
# Threshold = 1000. 800 < 1000 -> Ruled Out.
years_pe_algorithm(0, 0, 0, 800)

# Example 2: 1 Criteria, Moderate D-dimer (CTPA Indicated)
# PE most likely (1), D-dimer 600
# Threshold = 500. 600 >= 500 -> CTPA Indicated.
years_pe_algorithm(0, 0, 1, 600)

cliot documentation built on Dec. 1, 2025, 1:06 a.m.