Is venous reflux a common disease in post-thrombotic patients with unilateral deep vein thrombosis episode?

OBJECTIVES: To investigate reflux development and changes in resting venous diameters in the DVT and the non-DVT lower limbs. METHODS: Twenty subjects (40 limbs) with acute unilateral proximal DVT diagnosed by ultrasound, who were treated with low-molecular-weight-heparin (LMWH), followed by at least three months of oral warfarin therapy, were enrolled in the study. The limbs were classified according to CEAP (clinical, aetiologic, anatomic, pathophysiology) clinical classification on a scale of 0-6. Duplex ultrasound (DUS) was employed to assess DVT resolution, vein diameter and venous reflux in both limbs at intervals of zero, three, six and 12 months. Venous reflux was defined as a valve closure time more than 1 s. RESULTS: There were 13 men and seven women, average age was 40.8 years and average body mass index 27.7 kg/m2. In the DVT limbs at three, six and 12 months, deep veins were non-occluded in 40%, 60% and 85%, respectively. By 12 months, 16 (80%) had developed venous reflux, mostly in the femoral (FV) and popliteal veins (PV); eight limbs (40%) were in clinical classes 4-6. In the contralateral 20 non-DVT limbs, four limbs developed borderline reflux at the sapheno-femoral junction (SFJ) after six months and mean diameters of SFJ, FV and PV increased significantly. CONCLUSIONS: Venous reflux is highly likely to occur in DVT limbs within a year follow-up period. Venous dilatation can occur in the contralateral unaffected lower limb, consistent with a systemic effect. Our results are suggestive and further studies are needed.

Subcutaneous and intramuscular pressures in the post-phlebitic limb.

The mechanisms of pain in patients with chronic iliac vein obstruction and venous claudication is not fully understood. Ten patients with severe to moderate unilateral post-thrombotic syndrome with chronic iliac vein obstruction were studied. Subcutaneous tissue pressures and intramuscular pressures were measured using the slit-catheter technique in both legs, at rest and during exercise. The subcutaneous tissue pressure was higher, but not significantly higher, in the leg with iliac vein obstruction, +2 (-2 to +10) mmHg, than in the contralateral healthy legs, 0 (-4 to +4) mmHg in supine position at rest. During exercise in the standing position the subcutaneous tissue pressure rose significantly (p less than 0.01) in the diseased leg to 9 (+4 to +15) mmHg, while no such increase was seen in the control limb, 0 (-4 to +4) versus -1 (-5 to +4) mmHg. The intramuscular pressures were significantly higher (p less than 0.01) in the leg with iliac vein obstruction 26 (15 to 42) mmHg, than in the control leg, 11 (1 to 15) mmHg at rest in supine position as well as during exercise in standing position, 64 (35 to 82) mmHg and 26 (10 to 36) mmHg, respectively.

The relationship between subcutaneous tissue pressures and intramuscular pressures in normal and edematous legs.

The interstitial hydrostatic pressure is affecting fluid movements at microvascular level. A disturbance in the Starling equilibrium results in edema formation. The effect of venous outflow and lymphatic obstructions in human, on the interstitial fluid pressures subcutaneously and intramuscularly and the possible interaction between veins and lymphatics was studied. Utilizing a slit-catheter technique, subcutaneous tissue and intramuscular pressures were measured bilaterally in 10 patients with venous outflow obstruction and in 10 patients with lymphatic obstruction. In lymphatic obstruction the subcutaneous tissue pressure was significantly elevated as well as the intramuscular pressure, while in venous obstruction the subcutaneous tissue pressure was normal. The intramuscular pressure was significantly elevated during exercise reaching 60 mm Hg or more, combined with severe pain. Pain did not occur in patients with lymphatic obstruction. This study suggests that in lymphatic obstruction there is also an involvement of either deep lymphatics, venous dysfunction or a combination of both. Intramuscular pressures do not reach the critical level for pain during exercise. In venous obstruction mainly the intramuscular compartment is involved and interstitial pressure reaches values well above 60 mm Hg during exercise, at which level pain occurs, possibly due to tension of painreceptors in the muscle fascias.

Primary lymphedema of the leg: relationship between subcutaneous tissue pressure, intramuscular pressure and venous function.

In eight patients with unilateral primary lymphedema, subcutaneous tissue and intramuscular pressure were measured in both legs using the slit-catheter technique. Venous function was assessed by venography, or Doppler or photoplethysmography. Both at rest and during exercise, subcutaneous tissue pressure was elevated in the lymphedematous leg (17.9 +/- 7.6 and 33.0 +/- 10.8 mmHg respectively) compared to healthy contralateral leg (0.4 +/- 2.6 and -0.6 +/- 3.6 mmHg; p less than 0.001). The intramuscular pressure in the anterior tibial compartment was also increased at rest and during exercise in the edematous leg (24.9 +/- 4.4 mmHg and 43.6 +/- 11.2 mmHg respectively) compared to control leg (9.6 +/- 5.6 and 25.8 +/- 10.00 mmHg). These findings suggest that derangements in both the superficial and deep lymphatic systems as well as venous dysfunction contribute to the clinical appearance of "primary lymphedema."