Is the YEARS algorithm a safe and effective way to rule out acute pulmonary embolism in hemodynamically stable adult patients without contraindications to imaging?

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Is the YEARS Algorithm Safe for Ruling Out Pulmonary Embolism?

Yes, the YEARS algorithm is safe and effective for ruling out acute pulmonary embolism in hemodynamically stable patients, with a 3-month venous thromboembolism rate of only 0.61% and the major advantage of reducing unnecessary CT scans by 14% compared to traditional Wells criteria. 1, 2

How the YEARS Algorithm Works

The YEARS algorithm simplifies PE diagnosis by using only three clinical items from the Wells score combined with probability-adjusted D-dimer thresholds 1:

  • Clinical signs of deep vein thrombosis (unilateral leg swelling)
  • Hemoptysis
  • PE is the most likely diagnosis (more likely than alternative diagnoses)

D-dimer interpretation is adjusted based on the number of YEARS items present 1, 2:

  • Zero YEARS items: PE excluded if D-dimer <1000 ng/mL
  • One or more YEARS items: PE excluded if D-dimer <500 ng/mL
  • All other patients: Proceed to CTPA

Safety Evidence

The original YEARS study enrolled 3,465 patients across 12 Dutch hospitals and demonstrated robust safety 2:

  • 2,946 patients (85%) had PE ruled out without imaging
  • 18 patients (0.61%, 95% CI 0.36-0.96%) developed symptomatic VTE during 3-month follow-up
  • 6 patients (0.20%) had fatal PE during follow-up
  • This failure rate is well within the accepted safety threshold of <1% for PE diagnostic strategies 1, 2

External validation in an independent cohort of 3,314 patients confirmed these findings, with 42.9% of patients having PE safely ruled out without imaging 3. However, this validation study identified an important caveat: all 17 missed PE cases (1.2%) occurred in patients with zero YEARS items and D-dimer <1000 ng/mL but above their age-adjusted D-dimer cutoff 3.

Efficiency Gains

The YEARS algorithm reduces unnecessary CTPA by 14% compared to Wells criteria with a fixed 500 ng/mL D-dimer threshold 1, 2:

  • YEARS avoided CTPA in 48% of patients versus 34% with traditional Wells approach
  • This efficiency gain applies across all age groups, addressing the major limitation of standard D-dimer testing in elderly patients 1, 2

In primary care settings, the algorithm performed even better, ruling out PE in 80.6% of patients with a failure rate of only 0.50% 4.

Integration with Current Guidelines

The 2019 ESC Guidelines formally endorse the YEARS approach as a validated diagnostic strategy 1:

  • Class I, Level A recommendation for using clinical probability-adjusted D-dimer cutoffs
  • The YEARS algorithm is specifically mentioned as an alternative to age-adjusted D-dimer thresholds
  • Both approaches maintain sensitivity >97% while improving specificity 1

Critical Caveats and How to Apply Safely

Important Limitation: Age-Adjusted D-Dimer Overlap

The most significant safety concern is in patients with zero YEARS items and D-dimer between 500-1000 ng/mL who are >50 years old 3:

  • In the external validation, all 17 missed PE cases had D-dimer levels above their age-adjusted cutoff (age × 10 ng/mL)
  • Among 272 patients with zero YEARS items, D-dimer <1000 ng/mL but above age-adjusted cutoff, 6.3% had PE 3
  • Recommendation: In patients >50 years with zero YEARS items, consider using the lower of either 1000 ng/mL or the age-adjusted cutoff (age × 10 ng/mL) 3

When NOT to Use YEARS

Do not apply YEARS in the following situations 1:

  • Hemodynamically unstable patients (systolic BP <90 mmHg, shock, cardiac arrest) – proceed directly to imaging or bedside echocardiography 1
  • High clinical probability patients – the algorithm was designed for low-to-intermediate probability populations 1, 2
  • When point-of-care D-dimer assays are used – these have lower sensitivity (88% vs 95%) and should only be used with low pretest probability 1

Proper Clinical Application

Step-by-step algorithm 1, 2:

  1. Confirm hemodynamic stability – if unstable, skip YEARS and proceed to immediate imaging or bedside echo 1

  2. Assess the three YEARS items simultaneously with D-dimer testing (not sequentially):

    • Clinical signs of DVT?
    • Hemoptysis?
    • PE most likely diagnosis?

  3. Apply probability-adjusted D-dimer threshold:

    • Zero items + D-dimer <1000 ng/mL → PE excluded (no CTPA needed)
    • ≥1 item + D-dimer <500 ng/mL → PE excluded (no CTPA needed)
    • All others → Proceed to CTPA

  4. Age adjustment consideration for patients >50 years: If zero YEARS items and D-dimer is between 500-1000 ng/mL, compare to age-adjusted cutoff (age × 10 ng/mL); if above age-adjusted cutoff, proceed to CTPA 3

Comparison with Alternative Strategies

YEARS vs. PERC: Combining YEARS with PERC rule does not improve efficiency and may increase failure rates 5:

  • Only 6 of 154 patients (3.9%) with no YEARS items would have been PERC negative
  • Applying PERC before YEARS would increase failure rate to 1.42% (unacceptable) 5
  • Do not combine these strategies – use YEARS alone 5

YEARS vs. Age-Adjusted D-Dimer: Both are endorsed by ESC guidelines 1:

  • Age-adjusted D-dimer (age × 10 ng/mL for patients >50 years) increases specificity from 10% to 35% in patients >80 years 1
  • YEARS provides similar efficiency gains but uses clinical probability adjustment instead of age adjustment 1, 2
  • Either approach is acceptable; the key is to avoid the standard 500 ng/mL cutoff in all patients 1

U.S. Validation

A multicenter U.S. study of 1,789 emergency department patients confirmed the algorithm's performance 6:

  • 67% of patients avoided imaging using YEARS adjustment (vs. 53% with standard threshold)
  • Sensitivity 92.9% (95% CI 85-97%)
  • NPV nearly 100%
  • Six PE cases (0.5%) were missed, all with D-dimer between adjusted thresholds 6

Common Pitfalls to Avoid

Never use YEARS in high-probability patients – proceed directly to CTPA without D-dimer testing 1

Never apply the 1000 ng/mL cutoff to patients with ≥1 YEARS item – these patients require the standard 500 ng/mL threshold 1, 2

Never ignore age-adjusted D-dimer in elderly patients with zero YEARS items – if D-dimer is 500-1000 ng/mL and above age × 10 ng/mL, proceed to imaging 3

Never use point-of-care D-dimer assays with YEARS – only high-sensitivity laboratory assays (ELISA or turbidimetric) with sensitivity ≥95% are validated 1

Never skip clinical probability assessment – YEARS items must be documented before D-dimer results to avoid bias 1, 2

References

1
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

6
Research

Multicenter Evaluation of the YEARS Criteria in Emergency Department Patients Evaluated for Pulmonary Embolism.

Academic emergency medicine : official journal of the Society for Academic Emergency Medicine, 2018

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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