A SIMPLE ULTRASOUND APPROACH FOR DETECTION OF RECURRENT PROXIMAL-VEIN THROMBOSIS

Background. The objective of this study was to develop a simple ultrasound method for measuring thrombus regression in patients with proximal deep-vein thrombosis (DVT) and to test its utility for the detection of DVT recurrence. Methods and Results. The study comprised a cross-sectional survey and a prospective investigation (149 and 145 patients, respectively). In both phases, the normalization rate of a previously abnormal ultrasound test, applying the criterion of full compressibility of the common femoral and popliteal veins (C-US method), was assessed. In the prospective study, the vein diameter under maximum compression (thrombus thickness) was measured in the abnormal venous segments at scheduled times (1, 3, 6, and 12 months). In patients presenting with suspected DVT recurrence, the procedure was repeated and results were compared with those available from the previous examination. Noncompressibility of a previously normal(ized) venous segment and enlargement of thrombus thickness (greater-than-or-equal-to 2 mm) were considered diagnostic of proximal DVT recurrence. The diagnostic accuracy of the C-US method alone, as well as of the combined ultrasound methods (C-US + thrombus thickness), was assessed against contrast phlebography. C-US test normalization occurred in only 30% of patients within 1 year. A significant reduction of the thrombus mass (P<.0001) was recorded throughout the entire study period. However, a major decrease in thrombus mass (>50%) was recorded within the first 3 months. Of 29 patients who developed a suspected recurrent DVT, phlebography confirmed diagnosis in 11. The C-US method alone showed an excellent accuracy (100%) but was applicable in only 6 patients (21%). Both the sensitivity and the specificity for proximal DVT recurrence of the combined ultrasound methods were 100% (95% confidence interval, 69% to 100% and 81% to 100%, respectively) and were applicable in all patients. Conclusions. The serial ultrasound measurement of thrombus mass after an acute episode of DVT may allow the correct identification of patients who develop a recurrent proximal-vein thrombosis.