Regular ArticleLow molecular weight heparin (Innohep) as thromboprophylaxis in outpatients with a plaster cast: A venografic controlled study
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.
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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)
- et al.
Thromboprophylaxis with low-molecular-weight heparin in outpatients with plaster-cast immobilisation of the leg
Lancet
(1995) - 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) - et al.
Deep venous thrombosis and pulmonary embolism following cast immobilization of the lower extremity
J Foot Ankle
(1996) - et al.
Prospektivrandomisierte Pilotstudie zur ambulanten Thromboembolieprophylaxe
Unfallchirurg
(1998) - et al.
Ist eine Thromboembolieprophylaxe bei ambulanter und konservativer Therapie der fibularen Bandruptur des Oberen Sprunggelenks erforderlich?
Unfallchirurg
(1994)
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2020, Thrombosis UpdateCitation 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].