Postthrombotic syndrome after isolated calf deep venous thrombosis: the role of popliteal reflux

The purpose of this study was to evaluate the long-term clinical and hemodynamic outcomes after isolated first-time calf deep venous thrombosis (cDVT).

This retrospective clinical study was set in an academic referral center. From 1990 to 1994, 617 patients were seen with acute DVT. This number included 82 patients with phlebographically confirmed cDVT. Of those patients, 50 attended the clinical assessment 6 to 10 years (mean, 8.4 years) after the acute event. All patients with cDVT underwent treatment with anticoagulant therapy (96% heparin and warfarin, 4% only warfarin). The duration of the heparin treatment was 4.0 to 8.0 days (mean, 6.4 days), and warfarin was given for 2.0 to 7.5 months (mean, 3.4 months). Compression stockings were used regularly (mean, 9.2 months; range, 0.25 to 64 months) in 30% of the patients after acute cDVT. The initial ipsilateral phlebograms were reevaluated to confirm the diagnosis of cDVT without popliteal involvement. The clinical assessment included evaluation of both legs according to CEAP clinical classification C0-6. Bilateral color-flow duplex scan imaging was performed to assess reflux in deep popliteal segments. Photoplethysmographic measurement of venous refilling time was conducted in both legs to observe deep reflux.

The mean age was 57 years (range, 30 to 76 years) at the time of the clinical assessment. Cause of acute cDVT was idiopathy in 52%, coagulopathy in 2%, trauma in 10%, immobilization in 22%, and postoperative in 14% of the cases. During the follow-up period, seven recurrent DVTs (14%) were seen. In the clinical assessment, 17 legs (34%) with previous cDVT had skin changes (CEAP C4-6). No active ulcers were found. Contralaterally, the frequency of C4-6 was 10% (n = 5; P <.05). After exclusion of recurrent DVTs, the distribution of the clinical classification still remained the same. Deep popliteal reflux was detected in 20 legs (40%) with previous cDVT. Contralaterally, popliteal reflux was seen in nine cases (18%; P <.05). Plethysmography showed deep reflux in 16 legs (33%) with cDVT and in nine cases (18%) contralaterally (P >.05). A significant association was found between deep popliteal reflux and skin changes (P <.05).

In the long-term follow-up, cDVT may lead to significant postthrombotic disease. Reflux in the primarily uninvolved popliteal vein is frequent and may be associated with more severe disease.