Use of D-dimer and lower extremity Doppler ultrasound results to obviate the need for computerised tomographic pulmonary angiography.

UNLABELLED We hypothesise that correct interpretation of other diagnostic tests could reduce the use of computerised tomographic pulmonary angiogram (CTPA) examinations in patients with suspected pulmonary embolism (PE). MATERIALS AND METHODS We carried out a retrospective analysis of 158 patients in a 928-bed university hospital. These consecutive patients were investigated for suspected PE from May 2001 to February 2002 using CTPA. RESULTS There were 74 men and 84 women with a mean (+/-SD) age of 57 (+/-19) years. Overall, 56% of patients (89/158) showed clinically significant abnormalities on the CTPA examination. The overall prevalence of PE was 15% (24/158). The D-dimers were assayed in 40% (63/158) and lower limbs were scanned with Doppler ultrasound (US) in 22% (35/158) of patients. None of the 19 patients with negative D-dimer assays had PE. Of the patients who were positively tested on Doppler US, 4 were positive and 1 was negative for PE on the CTPA. None of the patients with positive Doppler US had negative D-dimer test. In retrospect, patient management based on negative D-dimer assays and positive lower extremity Doppler US studies could have reduced the need for further investigation with CTPA by 15% (24/158). CONCLUSION In patients with suspected PE, correct interpretation of D-dimer and leg Doppler US tests may reduce the demand for CTPAs.