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Q In patients with a first episode of acute symptomatic proximal deep venous thrombosis (DVT), do below knee elastic compression stockings prevent the post-thrombotic syndrome (PTS)?
Clinical impact ratings GP/FP/Primary care★★★★★★☆ IM/Ambulatory care ★★★★★★☆ Internal medicine ★★★★★★☆ Haematology ★★★★★☆☆
METHODS
Design:
randomised controlled trial.
Allocation:
Blinding:
blinded {data collectors, outcome assessors, and monitoring committee}†.*
Follow up period:
mean 49 months (range 6–60 mo).
Setting:
university hospital in Padua, Italy.
Patients:
180 patients (mean age 62 y, 57% women) with a first episode of acute symptomatic proximal DVT (confirmed by ultrasonography) who were receiving conventional anticoagulant treatment. Exclusion criteria were recurrent ipsilateral DVT, pre-existing leg ulcers or signs of chronic venous insufficiency, bilateral thrombosis, a short life expectancy, or contraindication for use of stockings.
Interventions:
daily wearing of below knee, graded, elastic compression stockings on the affected leg (30–40 mm Hg of pressure at the ankle) for 2 years (n = 90) or not wearing elastic compression stockings (n = 90).
Outcomes:
PTS on the side of the index DVT. PTS was defined by assessing the presence and severity of 5 leg symptoms and 6 objective signs. For each symptom or sign, a score of 0–3 was assigned using the contralateral unaffected leg as the denominator. A score ⩾15 on ⩾2 consecutive visits assessed ⩾3 months apart was defined as severe PTS. A score of 5–14 on 2 consecutive visits assessed ⩾3 months apart was defined as mild PTS. A lower limb venous ulcer was consistently classified as severe PTS.
Patient follow up:
100% (intention to treat analysis).
MAIN RESULTS
Patients in the stocking group had a lower rate of PTS than did those in the no stocking group (table).
Elastic compression stockings v no elastic compression stockings to prevent the post-thrombotic syndrome at mean 49 months in acute symptomatic proximal deep venous thrombosis (DVT)*
CONCLUSION
In patients with a first episode of acute symptomatic proximal deep venous thrombosis, below knee elastic compression stockings reduced the development of the post-thrombotic syndrome.
Abstract and commentary also appear in ACP Journal Club.
Commentary
PTS is a complication of DVT and is characterised by swelling, pain, discoloration, and in some cases, venous ulcer formation. Often the sequelae of PTS are irreversible. The study by Prandoni et al adds to previously published evidence suggesting that the risk of PTS may be reduced by wearing elastic compression stockings.1 Patients with a first episode of proximal DVT were assigned to wear or not to wear elastic compression stockings (30–40 mm Hg at the ankle) for 2 years. The primary outcome, a composite of “mild” or “severe” PTS, was defined by a standardised score determined (at least once annually for 5 y) by the patient’s symptoms and the physical examination findings of an investigator blinded to treatment assignment. The approximately 50% reduction in PTS among patients in the stocking group is noteworthy and is consistent with previously published data.1
Unfortunately, this study, much like previous studies, is limited by the lack of a placebo control group. Because about half the score used to determine whether a patient had PTS was assessed by the presence and severity of symptoms, the potential for reporting bias was substantial. The authors’ acknowledgment that elastic compression stockings “seem to affect clinical symptoms more than objective signs” emphasises the need for a trial with a double blind design or a trial with more objective outcome measurements.
These methodological flaws notwithstanding, PTS is common and below knee elastic stockings are an inexpensive, well tolerated intervention.2 Although the 30–40 mm Hg pressures used in this study may be intolerable for some patients, Prandoni et al report that only 2 of the 90 patients assigned to stockings withdrew because of discomfort. Mounting, albeit imperfect, evidence suggests clinicians should have a low threshold to use elastic compression stockings to reduce the risk of PTS in patients with proximal DVT.