Summary
Because the use of radioactive fibrinogen uptake test (FUT) has become questionable
both for ethical (risk of virus transmission) and technical (lack of sensitivity)
reasons, we investigated the potential value of two alternative methods for screening
of asymptomatic deep venous thrombosis following elective digestive surgery: liquid
crystal contact thermography (LCCT) and measurement of plasma concentration of D-dimer
(DD), as compared with bilateral ascending phlebography. Out of 194 patients, 185
underwent phlebography on the 8th (0-19, median and range) postoperative day. Despite
prophylaxis with low-molecular-weight heparin and elastic stockings, DVT was detected
on phlebography in 58 legs of 45 patients. Sensitivity of LCCT with respect to the
presence of DVT was 55% (n = 184 patients) or 28% (n = 368 legs) with a specificity of 67% and 82%, respectively. These poor performances
were obtained despite a good interobserver agreement for the LCCT assessments (overall
kappa coefficient of 0.66 between three experts). The most accurate cut-off of DD
for discriminating patients with or without DVT was 3,000 pg/1, as determined by ROC
curve analysis. Sensitivity of a DD level of more than 3,000 pg/1 for the presence
of phlebographically documented DVT on the 8th postoperative day was 89% for a specificity
of 48%.
Thus, LCCT cannot be used for screening of postoperative, mainly asymptomatic DVT
following general surgery. On the other hand, measurement of plasma DD may be useful
for initial screening, a negative result (level less than 3,000 pg/1) allowing to
exclude DVT (negative predictive value of 93%) and a positive result (positive predictive
value of 35%) requiring confirmation by phlebography. This sequential approach might
be useful in studies of the efficacy of antithrombotic regimens for prophylaxis of
DVT in patients at risk.
