Elsevier

Thrombosis Research

Volume 105, Issue 6, 15 March 2002, Pages 477-480
Thrombosis Research

Regular Article
Low molecular weight heparin (Innohep) as thromboprophylaxis in outpatients with a plaster cast: A venografic controlled study

https://doi.org/10.1016/S0049-3848(02)00059-2Get rights and content

Abstract

Introduction: The aim of this study was to investigate the incidence of deep vein thrombosis (DVT) in patients immobilized in plaster cast and the possible efficacy of prophylaxis with low molecular weight heparin (LMWH). Material and methods: The study was a randomized, assessor-blinded, open multicenter (three centers) study. All patients over 18 years of age with planned plaster cast on a lower extremity of at least 3 weeks were eligible for participation. Written informed consent was obtained from 300 patients and they were randomized to either 3.500 IU anti-Xa of tinzaparin (Innohep) subcutaneously once daily or no prophylaxis. On the day the cast was removed, ascending unilateral venography was performed. Two experienced radiologists, unaware of treatment, assessed the pictures independently. The radiologist had to obtain consensus as to whether DVT was present or not. Results: 300 patients were included (148 in the treatment group and 152 in the control group). Ninety-five were subsequently withdrawn. DVT was diagnosed in 10/99 patients in the treatment group and in 18/106 patients in the control group. This difference is not significant (P=.15, χ2 test) and the odds ratio was 0.55 (95% confidence interval=0.34–1.26). Conclusion: DVT in legs after plaster casting is a big problem, with an incidence of almost 20%. An effective prophylactic regime is required. Once-daily dose of 3.500 IU anti-Xa of tinzaparin was not sufficient.

Introduction

For the last 7 years, several authors have published papers regarding the incidence of deep vein thrombosis (DVT) in outpatients wearing plaster cast [3], [6], [7], [8], [9], [10]. These studies have used different clinical and paraclinical methods for diagnosing DVT. None of the studies have used venography, regarded as the “the golden standard” in the detection of DVT in nonsymptomatic patients. The results of these studies have, however, shown a possible benefit of LMWH as DVT prophylaxis in the whole casting period.

Our study was ended in 1998 and is the first study in which the “gold standard” (venography) has been used as an outcome parameter in the comparison of low molecular weight heparin (LMWH) with a control group without any prophylaxis in outpatients treated with plaster cast for at least 3 weeks.

Section snippets

Materials and methods

The study was designed as a randomized, assessor-blinded, open multicenter (three centers) study. Patients over the age of 18 with planned plaster cast on a lower extremity for at least 3 weeks irrespective of diagnosis were eligible for participation.

Exclusion criteria were pregnancy, allergy to heparin or contrast media, known liver or renal impairment, uncontrolled hypertension, bleeding disorders, cerebral insults due to bleeding, recent gastrointestinal bleeding and inability to perform

Statistical considerations

In the planning of the study, it was considered that the incidence of DVT without treatment was 15%. With a power of 80%, a 5% level of significance and a MEREDIF of 10% the number of 140 patients in each group were considered enough when a one-sided test was applied. The study was analyzed on a “fulfilled study” basis using a χ2 test for binomial data and a t test for continuous data.

Results

Three hundred patients were randomized (148 in the treatment group and 152 in the control group) and the demographics are shown in Table 1.

Ninety-five patients did not reach objective endpoint due to various reasons (Table 2). In the treatment group, 49 did not fulfill the study. Of these, 18 patients stopped due to discomfort with self-injection and 4 developed hematomas at injection site. One patient in the treatment group had metrorrhagia. In the control group, 46 patients did not fulfill

Discussion

Because of the introduction of LMWH in the mid-1980s, prophylaxis against venous thromboembolic complications in many different clinical situations has been investigated. During the last 7 years, nine studies [2], [3], [4], [5], [6], [7], [8], [10] have evaluated the risk of DVT in outpatients wearing a plaster cast on a lower extremity for fractures or tendon ruptures. Several studies [3], [6], [7], [8], [10], [11] have evaluated the effect of different LMWHs as thromboprophylaxis in these

References (11)

  • H.-J. Kock et al.

    Thromboprophylaxis with low-molecular-weight heparin in outpatients with plaster-cast immobilisation of the leg

    Lancet

    (1995)
  • L. Bara et al.

    Occurrence of thrombosis and hemorrhage, relationship with anti-Xa, anti-IIa activities, and D-diner plasma levels in patients receiving a low molecular weight heparin, enoxaparin or tinzaparin, to prevent deep vein thrombosis after hip surgery

    Br J Haematol

    (1999)
  • N. Fawaz et al.

    Deep venous thrombosis and pulmonary embolism following cast immobilization of the lower extremity

    J Foot Ankle

    (1996)
  • H. Gehling et al.

    Prospektivrandomisierte Pilotstudie zur ambulanten Thromboembolieprophylaxe

    Unfallchirurg

    (1998)
  • H. Gehling et al.

    Ist eine Thromboembolieprophylaxe bei ambulanter und konservativer Therapie der fibularen Bandruptur des Oberen Sprunggelenks erforderlich?

    Unfallchirurg

    (1994)
There are more references available in the full text version of this article.

Cited by (119)

  • The (T) thrombosis (I) in patients with (L) lower (L) limb (I) injuries (R)requiring (I) immobilisation (TILLIRI) study: A prospective observational multicentre study

    2020, Thrombosis Update
    Citation Excerpt :

    One clinically relevant non-major bleeding event occurred in 1 patient in the treatment group and none in the control group. Other published randomised controlled trials (RCTs) have had significant methodological limitations (including underpowering for the primary outcome) and include studies that have reported the incidence of asymptomatic VTE events and highly variable VTE rates [5,7,9–11,28]. Lapidus et al. randomised patients following ankle fracture surgery to dalteparin or placebo for 5 weeks and reported asymptomatic VTE rates of 21% (95% CI: 13–29%; proximal DVT 4% and 3% respectively) with no difference between groups and no major bleeding [11].

View all citing articles on Scopus
View full text