Compression Stockings and the Prevention of Symptomatic Venous Thromboembolism: Data From the Tinzaparin in Acute Ischemic Stroke Trial

Testing devices for the prevention and treatment of stroke and its complications

We are entering a challenging but exciting period when many new interventions may appear for stroke based on the use of devices. Hopefully these will lead to improved outcomes at a cost that can be afforded in most parts of the world. Nevertheless, it is vital that lessons are learnt from failures in the development of pharmacological interventions (and from some early device studies), including inadequate preclinical testing, suboptimal trial design and analysis, and underpowered studies. The device industry is far more disparate than that seen for pharmaceuticals; companies are very variable in size and experience in stroke, and are developing interventions across a wide range of stroke treatment and prevention. It is vital that companies work together where sales and marketing are not involved, including in understanding basic stroke mechanisms, prospective systematic reviews, and education of physicians. Where possible, industry and academics should also work closely together to ensure trials are designed to be relevant to patient care and outcomes. Additionally, regulation of the device industry lags behind that for pharmaceuticals, and it is critical that new interventions are shown to be safe and effective rather than just feasible. Phase IV postmarketing surveillance studies will also be needed to ensure that devices are safe when used in the 'real-world' and to pick up uncommon adverse events.

Physical methods for preventing deep vein thrombosis in stroke

BACKGROUND

Deep vein thrombosis (DVT) and resulting pulmonary embolism (PE) are important complications of stroke. Physical methods to reduce the risk of DVT and PE, such as graduated compression stockings (GCS) or intermittent pneumatic compression (IPC) applied to the legs, do not appear to be associated with any bleeding risk and reduce the risk of DVT in some categories of surgical patients. We sought to assess their effects in stroke patients.

OBJECTIVES

To assess the effectiveness and safety of physical methods of reducing the risk of DVT, fatal or non-fatal PE and death in patients with recent stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched November 2009), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2009), MEDLINE (1966 to November 2009), EMBASE (1980 to November 2009), CINAHL (1982 to November 2009) and The British Nursing Index (1985 to November 2009). We screened reference lists of all relevant papers, searched ongoing trials registers (November 2009) and contacted experts in the field.

SELECTION CRITERIA

Unconfounded randomised controlled trials comparing physical methods for reducing the risk of DVT with control and in which prophylaxis was started within seven days of the onset of stroke.

DATA COLLECTION AND ANALYSIS

Two review authors searched for trials and extracted data.

MAIN RESULTS

We identified two trials of GCS that included 2615 patients and two small studies of IPC that included 177 patients. Overall, physical methods were not associated with a significant reduction in DVTs during the treatment period (odds ratio (OR) 0.85, 95% confidence interval (CI) 0.70 to 1.04) or deaths (OR 1.12, 95% CI 0.87 to 1.45). Use of GCS was not associated with any significant reduction in risk of DVT (OR 0.88, 95% CI 0.72 to 1.08) or death (OR 1.13, 95% CI 0.87 to 1.47) at the end of follow up. IPC was associated with a non-significant trend towards a lower risk of DVTs (OR 0.45, 95% CI 0.19 to 1.10) with no evidence of an effect on deaths (OR 1.04, 95% CI 0.37 to 2.89).

AUTHORS' CONCLUSIONS

Evidence from randomised trials does not support the routine use of GCS to reduce the risk of DVT after acute stroke. There is insufficient evidence to support the routine use of IPC to reduce the risk of DVT in acute stroke and further larger randomised studies of IPC are needed to reliably assess the balance of risks and benefits of this intervention.