Abstract
Rationale: The Wells criteria are recommended to improve pre-CTAL probability of PE. However, the criterion whether an alternative diagnosis is less likely than PE (alternative vs PE question), is often equivocal. Also, it is well documented that the likelihood of PE increases with increasing D-d levels, but only the cut-off to normal level is recommended to assess the need for CTAL.
Methods: Wells criteria and D-d levels of 200 consecutive patients who underwent CTAL were used to assess A. How often is the answer to the alternative vs PE question ambiguous and how such cases should be scored. B. If and how can integration of the level of D-d improve the pre-CTAL probability score for PE.
Results: PE was diagnosed in 29 (14.5%) of the patients. The answer to the alternative vs PE question was equivocal in 41% of all patients. The Wells score was higher in the PE group (4.4±2.0 vs. 1.7±1.5, p<0.001) only when the equivocal cases were considered to provide a negative answer (alternative diagnosis not less likely, = lower Wells score). Analysis of our results indicated that the best positive predictive value is obtained when the D-d value in micg/ml is simply added to the Wells score. A value <4 excluded PE, while reducing the number of patients required to undergo CTAL to less than half (from 6.9 to 3.4).
Conclusions: When the answer to the alternative vs PE question is unclear, no scoring should be given, thereby providing more weight to other criteria and D-d. Integrating the absolute level of D-d into the clinical decision may improve the pre-CTAL positive predictive value without reducing the negative predictive value.
- © 2014 ERS