Comparative Study of Prophylactic Agent for Venous Thromboembolism After Total Knee Arthroplasty
Information source: Hanyang University Seoul Hospital
ClinicalTrials.gov processed this data on August 23, 2015 Link to the current ClinicalTrials.gov record.
Condition(s) targeted: Venous Thromboembolism
Intervention: acetylsalicylic acid (Drug); rivaroxaban (Drug)
Phase: Phase 2
Status: Recruiting
Sponsored by: Hanyang University Seoul Hospital Official(s) and/or principal investigator(s): Choonghyoek Choi, Study Chair, Affiliation: Hanyang University
Overall contact: Jinkyu Lee, Phone: +82-10-9582-7004, Email: gaia-silver@hanmail.net
Summary
The purpose of this study is to compare the efficacy of two prophylactic agent(aspirin
300mg/day and rivaroxaban 10mg/day) for venous thromboembolism after total knee
arthroplasty.
Clinical Details
Official title: Comparative Study of Prophylactic Agent for Venous Thromboembolism After Total Knee Arthroplasty
Study design: Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Investigator), Primary Purpose: Prevention
Primary outcome: venous thromboembolism
Secondary outcome: bleeding tendency
Detailed description:
1. Thromboprophylactic regimens Aspirin®(acetylsalicylic acid, AA, Bayer) 300mg/day or
Xarelto® (rivaroxaban, factor Xa-inhibitor, Bayer) 10mg/day will be randomly(according
to the sequence of operation) administrated in oral route to the patients undergone
primary total knee replacement during postoperatively 10 days. Prophylaxis will be
started at 6 hours after the end of surgery. For all patients, intermittent pneumatic
compression will be initiated immediately after surgery, and a continuous passive
motion machine was applied at 1 day postoperatively.
2. Evaluation and treatment plan of a VTE event
Investigators will assess the patients for VTE(venous thromboembolism) by using a
64-channel multidetector-row computed tomography (MDCT) indirect venography system
(Brilliance 64®, Philips, Eindhoven, Netherlands) at 10 days postoperatively. Six
seconds after the reached 100 HU (Hounsfield units), a CT scan was performed from the
costophrenic angle to the lung apex, to obtain arterial phase images of the pulmonary
artery. Approximately 140 mL of contrast media (Ultravist 370®, Iopromide, Bayer) was
administered through the antecubital vein at a flow rate of 4 mL/s. At 140 seconds
after the injection of contrast media, indirect venography was performed from the liver
dome to the ankle to obtain contrast-enhanced venous phase images. Indirect venography
images were reconstructed with a slice width of 1 mm and an increment of 0. 5 mm. A
single radiologist evaluated the CT images in a blinded manner. Symptomatic PE was
defined as PE with additional symptoms, such as dyspnea, pleuritic chest pain, cough,
hemoptysis, tachypnea, rales, or tachycardia [26]. Symptomatic DVT was defined as DVT
involving discomfort of the calf or thigh, a Homan's sign, swelling, localized hotness,
skin discoloration, tenderness, or prominence of the superficial veins [30]. If the
patient presented symptoms of those mentioned above severely, we performed MDCT before
10 days postoperatively. The VTE cases were divided into PE and DVT, and further
subcategorized into proximal DVT (occurring in the popliteal vein and above) and distal
DVT (occurring below the popliteal vein).
If the patient had asymptomatic distal DVT, the patient was only observed
conservatively, without any treatment. We only treated patients with PE, symptomatic
DVT, or proximal DVT, and a pulmonologist or a chest surgeon was consulted for the
management of these patients with anticoagulants. At 3 months postoperatively, patients
who had VTE events underwent follow-up MDCT to evaluate the change in VTE.
3. Sample size assessment/Statistical analysis The sample size and power calculation will
be based on the expected incidence of VTE. The incidence of VTE was expected
approximately 17% in aspirin group. 10% in xarelto group through our pilot study. If we
analyzed using chi-square test, we need 370 patients(each 185 patients for aspirin and
xarelto group) for proving that xarelto has a more effective than aspirin in VTE
prophylaxis. Statistical significance was set at 5% (p < 0. 05), with statistical power
of 80%; thus, the minimum sample size of each group was set as 185 cases.
Statistical analysis was performed with SPSS® version 18. 0 for Windows (SPSS Inc, Chicago,
IL, USA). For categorical variables, the Chi-square test was used to compare VTE proportions
between different groups. If more than 20% of the expected frequencies were less than 5, the
Fisher's exact test was performed. Moreover, one-way analysis of variance was used to
compare the results of numerical continuous variables. However, for some variables without
normal distribution, the Kruskal-Wallis test was used instead.
Eligibility
Minimum age: N/A.
Maximum age: N/A.
Gender(s): Both.
Criteria:
Inclusion Criteria:
- all patients undergone primary total knee arthroplasty
Exclusion Criteria:
- renal insufficiency, contrast allergy, simultaneous bilateral TKA, hemorrhagic
disorder, sever liver disease
Locations and Contacts
Jinkyu Lee, Phone: +82-10-9582-7004, Email: gaia-silver@hanmail.net
Department of Orthopaedic Surgery, Hanyang University, College of Medicine, Seoul 133-792, Korea, Republic of; Recruiting Jinkyu Lee, Phone: +82-10-9582-7004, Email: gaia-silver@hanmail.net
Additional Information
Starting date: October 2014
Last updated: November 5, 2014
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