A prospective reassessment of the utility of the Wells score in identifying pulmonary embolism.
OBJECTIVE
To assess whether a cumulative clinical risk score (Wells score) can optimise imaging strategies in patients with suspected pulmonary embolism (PE).


METHODS
Prospective, consecutive series of 633 studies on 595 patients referred to a major teaching hospital for ventilation/perfusion (V/Q) scanning for suspected acute PE between September 2004 and November 2005. Ventilation scintigraphy was performed using technetium-99m Technegas, and V/Q results were interpreted in conjunction with Wells scores.


METHODS
Likelihood of PE for each Wells score interval; overall prevalence of PE.


RESULTS
The likelihood of PE for a given Wells score in our study was not significantly different from the likelihood in the original study by Wells et al. Scores of < 2 in our study were associated with a 4% risk of PE, scores between 2 and 6 with a 13% risk, and scores > 6 with a 67% risk. The overall prevalence of PE in our study was significantly less than that in the original study (9% v 16%; P < 0.01), attributable to a significantly larger proportion of our patients having scores of < 2 (66% v 40%; P < 0.0001).


CONCLUSIONS
The Wells score remains a robust clinical tool for stratifying the likelihood of PE. Patients with Wells scores of > 2 warrant imaging assessment for PE, but for those with scores < 2, further imaging may be problematic.
Yap
Kenneth S K
KS
Department of Nuclear Medicine, The Alfred Hospital, Melbourne, VIC, Australia. kskyap@yahoo.com
Kalff
Victor
V
Turlakow
Alla
A
Kelly
Michael J
MJ
D000328:Adult; D006801:Humans; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000145:classification / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D013667:Technetium; D014057:Tomography, X-Ray Computed / Q000379:methods; D014692:Ventilation-Perfusion Ratio
D013667:Technetium