The postthrombotic syndrome in relation to venous hemodynamics, as measured by means of duplex scanning and strain-gauge plethysmography

Purpose: Venous hemodynamics were evaluated in relation to the postthrombotic syndrome (PTS) 7 to 13 years after deep venous thrombosis (DVT). Methods: The presence of flow, reflux, and compressibility of 1394 vein segments in 82 patients was assessed by means of duplex scanning. The venous outflow resistance was measured by means of strain-gauge plethysmography. The venous hemodynamics were related to the clinical severity of the PTS, characterized by the CEAP (clinical, etiologic, anatomic, pathophysiologic) classification. Results: In patients with severe clinical symptoms of PTS, the prevalence of reflux was significantly higher. There was no relationship between the severity of the PTS and the noncompressibility or the combination of reflux and noncompressibility or an increased venous resistance. By means of multiple regression analysis with the variables of age, gender, reflux, and venous resistance, age and reflux were shown to be the main contributors to the severity of PTS. Significantly more patients (64%) with severe signs of PTS had a combination of deep and superficial reflux. In each of the traceable vein segments, the mean of the CEAP classification was calculated for the vein segments with and without reflux. In the proximal superficial femoral vein (P < .001), distal superficial femoral vein (P < .05), and popliteal vein (P < .05), a significantly higher mean CEAP classification was found in the veins with reflux, whereas in the distal, long, and short saphenous veins, no such relationship was found. Conclusion: Most patients with severe PTS had a combination of deep and superficial reflux. Reflux in the deep proximal veins contributes significantly to the PTS.