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Reducing the risk of venous thromboembolism in patients with acute stroke: more evidence from the CLOTS Trial Collaboration
  1. Tom Treasure
  1. Correspondence to Professor Tom Treasure, Professor of Cardiothoracic Surgery, Clinical Operational Research Unit (CORU), UCL (Department of Mathematics), 4 Taviton Street, London WC1H 0BT, UK; tom.treasure{at}

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In 2009, the CLOTS (Clots in Legs Or sTockings after Stroke) Trial Collaboration reported a study of prevention of deep vein thrombosis (DVT) in 2518 patients who were immobile due to a recent (<1 week) acute stroke. They were randomised 1:1 to the intended use or avoidance of thigh length graduated compression stockings. After about 7–10 days, compression Doppler ultrasound was performed by a technician from whom the allocation was concealed. DVT, the primary outcome, was similar (10.0% vs 10.5%) in the two groups. However, ulcers, blisters, skin breaks and necrosis were significantly more common (5% vs 1%) in those who had stockings. Compliance with the allocated treatment was high (97% vs 95%).1

At the time the CLOTS Trial Collaboration was reported, work was near completion on NICE guidance for venous thromboembolism (VTE) prophylaxis in all hospitalised patients. Given the concerns regarding the administration of heparin in recent stroke, stockings (and other forms of mechanical/non-pharmacological) prophylaxis was an alluring route out of this dilemma, but given the inescapable conclusion from CLOTS, that stockings were ineffective in reducing DVT and were actively harmful, the position had to be reconsidered. Publication of the near-completed NICE guidance was put on hold …

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  • Competing interests None.

  • Provenance and peer review Commissioned; externally peer reviewed.

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