BACKGROUND: The current deep vein thrombosis (DVT) diagnostic algorithms are rarely followed in clinical practice due to complexity and time constraints. Simplified alternatives are needed to enhance adherence while maintaining diagnostic accuracy. The ToDay algorithm was developed to address these concerns by combining physician implicit assessment of DVT likelihood with D-dimer testing.
OBJECTIVES: The objective of the study is to validate the ToDay algorithm using previously collected data.
METHODS: This analysis used data from the 4D study (NCT02038530), a multicenter study evaluating DVT diagnostic strategies. The ToDay algorithm considers DVT excluded without further testing if DVT is considered most likely and D-dimer <500 ng/mL or if DVT is not considered most likely and D-dimer less than age-adjusted threshold. The primary outcome was 90-day symptomatic venous thromboembolism (VTE). Secondary outcome was not requiring ultrasound imaging.
RESULTS: Among 1497 patients, 163 (10.9%) were diagnosed with DVT. Of the 1334 patients who had DVT excluded by the ToDay algorithm, 10 patients were found to have VTE during follow-up, a failure rate of 0.75% (95% CI, 0.41-1.37). Of all patients, 38.6% (95% CI, 36.2-41.1) did not require ultrasound imaging.
CONCLUSION: The ToDay algorithm was found to be a safe and efficient alternative for DVT testing, reducing reliance on ultrasound imaging. It simplifies the diagnostic process, making it more feasible for emergency settings. Prospective validation is required before clinical adoption.
| Discipline Area | Score |
|---|---|
| Emergency Medicine |  |
| Hemostasis and Thrombosis | |
| Family Medicine (FM)/General Practice (GP) | |
| General Internal Medicine-Primary Care(US) | |
The ToDay simplified diagnostic algorithm for deep vein thrombosis showed clinical usefulness in ruling out lower extremity DVT (while also reducing more ultrasounds versus using the traditional Well's criteria and Ddimer). Before implementation, however, there are limitations in this study: 1) the data set that excluded calf DVT may have biased the results to show it is better than the initial results; 2) this pathway only uses 1 factor to risk stratify. It's unclear whether this pathway would work for a truly high-incidence population (e.g., cancer patients); and 3) this is a retrospective look and it's unclear whether prospectively the results would be similar.
Suggests that clinician gestalt and a negative D-dimer can eliminate the need for US for many patients with suspected DVT.
This demonstration of clinical utility of the “ToDay” algorithm as a high-performing, cost-reducing, and timely/rapid assessment of DVT probability is a promising tool. As the authors state, this awaits a robust prospective validation before being adopted into clinical practice, but is among the few bedside-usable tools in DVT/VTE clinical diagnostics likely to improve care in this area since the initial version of the Wells Score approach (Lancet, 1997).
