Central assessment of bilateral phlebograms in a major multicentre thromboprophylactic trial. Reasons for inadequate...

To determine the cause of inadequate bilateral phlebograms at central assessment. A major antithrombotic trial was evaluated to identify and apply corrective measures for reducing inadequate results in future multicentre trials.

The inadequate results in 253 out of 1,827 patients having undergone bilateral phlebography following total hip replacement were reviewed by two central assessors using strict criteria for evaluability. The reasons for inadequate findings were assessed and ranked.

Insufficient contrast filling, especially of the anterior tibial, common femoral and iliac veins, was the most common reason for disqualifying examinations. Unilateral examinations and obscuring metallic devices were the second and third most common reasons, respectively. Efforts should be made to standardize the phlebography technique, to use a large volume of contrast without tourniquets, and to obtain an appropriate number of views to visualize the deep veins.