Abstract
Introduction: CTPA is the recommended diagnostic modality for pulmonary embolism and the Well's score is a well-known measure of pre-test probability. We undertook a retrospective audit to examine the correlation between Wells score > 4 and CTPA positivity.
Methods: We obtained all CTPA requests undertaken in a teaching hospital between January and August 2013. Our hospital CTPA requests are made electronically requiring clinical details, Wells score and D-Dimer. If the Wells score is > 4 then a PE is considered likely and D-dimer is not required. Excluding duplicate requests or cancelled scans left a total of 800 requests. Of these, 747 CTPAs and 53 V/Q scans were performed (data excluded). Of these 747 CTPAs we had data from the initial request forms including Wells score and D-dimer for 693 of these patients.
Results: 747 CTPAs were performed during the study period. Of those, 1% (7) were equivocal, 83% (619) negative and 16% (121) positive. Of the positive CTPA scans 13 were excluded as request form details were not recorded leaving a total of 108. 72% (78) of these patients had a Well's score of > 4, 28% (30) had a Wells score of < 4. Of the negative CTPA scans 41 were excluded as request form details were not recorded leaving a total of 578. Of the negative CTPA total 78% (452) had a Wells score > 4. 22% (126) had a Wells score of < 4.
Conclusion: Despite having an online requesting system which takes a high pre-test probability (Wells>4) into account, excessive CTPA requests were made. This presents an interesting finding and we plan to re-audit after conducting training sessions on the use of the Wells score.
- © 2014 ERS