[Discrepancies between the results of phlebography and Doppler ultrasonography in the diagnosis of asymptotic venous thrombosis after total hip prosthesis. False negatives of phlebography or false positives of Doppler ultrasonography].
OBJECTIVE
Assess the diagnostic performance of phlebography and discrepancies with duplex ultrasonography in screening for asymptomatic deep vein thrombosis after total hip arthroplasty. Search for arguments which would favor contributing false-negatives or false-positives to one of the two exploration methods.


METHODS
The study included 24 patients who underwent the 2 explorations independently between day 7 and day 14 in a multicentric therapeutic trial of a new heparin. Discrepancies between the two techniques were recorded. Diagnostic performance of phlebography was calculated from contingency tables. The phlebograms were then reviewed with knowledge of the duplex ultrasonographic findings. The course of the venous thrombus after treatment was monitored with duplex ultrasonography.


RESULTS
Phlebography allowed the diagnosis of thrombus formation in 9 patients. Ultrasonography provided the diagnosis in 14 cases out of 24. Sensitivity of phlebography compared with duplex ultrasonography was 64% (95% CI = 35.1-87.2) (9/14) and specificity was 100% (95% CI = 69.1-100) (10/10). Several localizations were not visualized with phlebography: 3 partially obstructive thrombi near the femoral junction, and 38 distal thrombi including 31 soleus thrombi (fig. 5). When the phlebograms were reviewed again, defects compatible with a partial thrombus were found for the 3 proximal localizations and for 2 of the distal localizations (fig. 1, 2, 4). None of the soleus localizations were visualized. Duplex ultrasonographic follow-up concerned 12 of the 14 patients with a thrombus identified by duplex ultrasonography involving 44 localizations. In five case, the operator was different from the operator for the initial duplex ultrasonography. Follow-up revealed: 1 new localization, 37 narrowings and 6 repermeabilizations.


CONCLUSIONS
The coherence of the duplex ultrasonographic follow-up and the presence of images compatible with partial thrombus on the revised phlebograms which had been initially interpreted as wash out flow constitute a group of arguments suggesting that the discrepancies observed should be considered as phlebography false-negatives. This defect in the sensitivity of phlebography has been reported by others in the literature both for distal and proximal localizations.
Laboratoire d'Explorations Fonctionnelles, CHU, Côte de Nacre, Caen.
M T
MT
Barrellier
E
E
Jouen
C
C
Creveuil
D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D010690:Phlebography; D011237:Predictive Value of Tests; D013924:Thrombophlebitis / Q000175:diagnosis* / Q000000981:diagnostic imaging; D018608:Ultrasonography, Doppler