Complete compression ultrasound for the diagnosis of proximal and distal deep venous thrombosis--a retrospective outcome study.

BACKGROUND: Compression ultrasound is considered the preferred test for the diagnosis of deep vein thrombosis of the leg (DVT). Since sensitivity for distal thrombosis is low-additional tests are required. We developed a protocol of complete compression ultrasound of all venous segments of the leg (CCUS). A retrospective outcome study was performed to get an estimate of the rate of indeterminate results necessitating repeated testing as well as for the clinical safety of CCUS in a cohort of consecutive, unselected patients. PATIENTS AND METHODS: Case records of all patients referred for clinical suspicion of deep vein thrombosis within a three months period were reviewed. Patients with negative CCUS were followed directly or via the general practitioner in order to know whether an episode of venous thromboembolism had been documented since the initial CCUS.
RESULTS: 132 inpatients and 154 outpatients were identified. Clinical probability was high in 50 patients, medium in 142, and low in 94. The first CCUS was negative in 209 cases. Five patients (1.8%) had repeated CCUS within the next 7 days because of incomplete visualisation of the distal veins and turned out to be negative as well. Of all 214 patients with negative CCUS a clinical follow-up information was obtained after 168 +/- 25 days. Five patients had died, none due to pulmonary embolism. In two patients deep vein thrombosis had been documented (0.9% [95% CI: 0.1-3.3%]) 148 and 172 days after CCUS, respectively.
CONCLUSION: CCUS for diagnosis of DVT needs to be repeated in very few cases only. Clinical safety seems to fall into the same range as with combined algorithms and should be tested in a prospective design. Patients with medium and high probability showed a very low incidence of DVT within three months following CCUS; therefore, they may be included in a prospective outcome study.