CLOTS 3: Inflatable Leg Sleeves Reduce DVT in Stroke

June 02, 2013

LONDON — Intermittent pneumatic compression with inflatable sleeves that fit over the legs reduced the occurrence of deep vein thrombosis (DVT) in immobile patients who had had a recent stroke in the CLOTS 3 study.

The study was presented at the European Stroke Conference in London on May 31 and published simultaneously in the Lancet.

Presenting the data, Martin Dennis, MD, University of Edinburgh, said: "We have shown that treatment with these inflatable sleeves is feasible, safe, and an effective means of reducing venothromboembolism in immobilized patients in the first few days after stroke. Our study also suggested that this therapy could reduce mortality. This should be standard of care for immobilized stroke patients."

Prof. Tony Rudd, chair of the Intercollegiate Stroke Guideline Group at the UK Royal College of Physicians, London, endorsed this view. "This study is a major breakthrough showing how a simple and safe treatment can save lives," he stated in a press release issued by the University of Edinburgh.

The sleeves are inflated for a few seconds, one leg at a time, to compress the veins in the legs every minute or so. "By causing contraction of the leg muscles, the sleeves mimic the process of walking in immobilized patients. This ensures blood is pushed around the system, rather than pooling in the legs," Prof. Dennis explained.

Intermittent pneumatic compression with inflatable sleeves

"DVT is a big problem in stroke patients, with the risk being particularly high in the first few weeks after a stroke, when patients are often immobilized," he said.

It is estimated that there are 130,000 new strokes each year in the United Kingdom alone, and approximately 60,000 of these patients are at risk for DVT because they are immobilized. "About 25% of these patients would get a DVT. This inexpensive treatment could prevent about 3000 DVTs and maybe up to 1500 deaths in the UK each year," Prof. Dennis suggested.

He explained that antithrombotic drugs such as heparin have been shown to reduce DVT, but any benefits in this regard have been offset by bleeding risks. "But use of these inflatable sleeves is not associated with an excess of any major adverse effects that might offset the benefits," he added.

Prof. Martin Dennis

For the study, 2876 patients within 3 days of hospital admission for a stroke were randomly assigned to wearing the compression sleeves (Kendall SCD Express; Covidien) or not. The thigh-length sleeves were worn day and night for up to 30 days or until discharge, death, or mobility (when the patient could walk to the bathroom). The average duration of use was 12 days.

Patients underwent compression duplex ultrasound of both legs at 7 to 10 days and, wherever practical, at 25 to 30 days to detect DVT. The primary outcome — DVT in the proximal veins within 30 days — was reduced by an absolute 3.6% in the intermittent compression group, and there was also a strong suggestion of a mortality reduction in the treated group.

Table. CLOTS 3: Major Results

Endpoint Intermittent Compression Control P Value
DVT within 30 days (%) 8.5 12.1 .001
Symptomatic DVT 4.6 6.3 .045
Pulmonary embolism 2.0 2.4 .453
Mortality at 30 days 10.8 13.1 .057
Mortality at 6 months 22.3 25.1 .059


The numbers needed to treat are 28 to prevent 1 proximal DVT, and 43 to prevent 1 death, Prof. Dennis reported.

On the observed reduction in death, he said: "The mortality result was unexpected. You might expect some reduction, but this was larger than we thought. It suggests more patients might be dying from DVT or pulmonary embolism than we realize."

He explained that in the days after a stroke, death is often attributed to pneumonia, but the symptoms are not dissimilar to pulmonary embolism, "so it is possible that many of these patients may be dying from pulmonary embolism instead."

The benefit was seen in all subgroups investigated and was evident in both ischemic and hemorrhagic stroke patients.

The main adverse effect was skin breaks, which occurred in 3% of the intermittent compression group vs 1% of control patients.

The sleeves are already used in some surgical patients, but this is the first time they have been shown to work in medical patients. "Some stroke centers use them already, but guidelines don't push them for stroke patients. There hasn't been any data in this population. They could also be appropriate for many other patient groups who are bed bound or hospitalized," Prof. Dennis commented.

He said the sleeves were more effective than compression stockings for DVT prevention. "Stockings have been shown to reduce DVT in surgical patients, but we tested them in stroke patients in CLOTS 1 and didn't see a reduction in DVT."

He suggested the sleeves should work out to be very cost-effective. "They only cost about £25 for 1 set, and most patients will only use 1 set, so that works out to about £2 to £3 a day."

In a comment accompanying the Lancet article, Scott M. Stevens, MD, Intermountain Medical Center, Murray, Utah, and Scott C. Woller, MD, University of Utah, Salt Lake City, point out that Intermittent pneumatic compression sleeves are hard to keep on patients, and adherence issues were noted in the trial.

However, they conclude that "CLOTS 3 has convinced us," and say they will use such devices in patients who have had a stroke and are immobile in hospital.

The trial was funded by the National Institute for Health Research Health Technology Assessment (NIHR HTA) Programme and the Chief Scientist Office Scotland. Covidien donated the inflatable sleeves.

Lancet. Published Online May 31, 2013. Abstract, Comment


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as: