Clinical trial NCT00432796: PERIOP 2 - A Safety and Effectiveness of LMWH vs Placebo Bridging Therapy for Patients on Long Term Warfarin Requiring Temporary Interruption of Warfarin.
Official title: A Double Blind Randomized Control Trial of Post-Operative Low Molecular Weight Heparin Bridging Therapy Versus Placebo Bridging Therapy for Patients Who Are at High Risk for Arterial Thromboembolism (PERIOP 2)
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: PHASE3
Conditions: Stroke
Keywords: Anticoagulation
Prosthetic heart valves
Atrial fibrillation
Bridging Therapy
Thromboembolism
Warfarin
Low Molecular Weight Heparin
Lead sponsor: London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's
Sponsor class: OTHER
Collaborators: name: Canadian Institutes of Health Research (CIHR)
name: Pfizer
First posted: 2007-02-08
Enrollment: 1473
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: The purpose of the study is to determine the effectiveness and safety of LMWH postoperative bridging therapy (standard of care) versus postoperative placebo bridging therapy (experimental arm)for patients with mechanical heart valves or atrial fibrillation or atrial flutter who are at high risk for stroke when warfarin is temporarily interrupted for a procedure.

Detailed description: There are a growing number of patients who receive long-term warfarin therapy for the prevention of arterial thromboembolism. The current approach to the perioperative management of anticoagulation (i.e. "bridging therapy") with low molecular weight heparin (LMWH) is not standardized and has not been assessed by adequate randomized studies. Most clinicians, however, recommend bridging therapy.

We have recently completed a multicentre single arm pilot study of LMWH bridging therapy. This study in 10 centres accrued 224 patients in 10 months. In the pilot study the postoperative thromboembolic event rate was 3.1% and 75% of these occurred in patients who had anticoagulation held due to bleeding.

Design:A prospective multicentre randomized double-blind controlled trial. Patients: Consecutive eligible and consenting patients from 11 teaching hospitals in Canada. A total of 1773 patients with prosthetic heart valves receiving long-term oral anticoagulation with warfarin or patients with atrial fibrillation/flutter and a major risk factor who require elective non-cardiac surgery or invasive procedure necessitating reversal of their oral anticoagulant therapy.

Treatment Schedule: Consent will be obtained preoperatively but randomization will be performed postoperatively after confirming eligibility.

Preoperative period: In all participants, warfarin therapy will be discontinued five days prior to the procedure. Dalteparin, a LMWH, will be administered at 200 IU/kg sc early in the morning for the three days prior to, but not including the day of, the procedure except on the day prior to surgery the dose will be 100 I.U./kg given 24 hours preoperatively. Warfarin will be resumed the evening of the procedure.

Postoperative period: Dalteparin or placebo will be administered daily (starting the morning after the procedure), provided surgical hemostasis is achieved, and will be continued for at least four days and until the INR is\>2.0. Patients considered at high risk for a postoperative major bleed will be given dalteparin or placebo at a dose of 5,000 IU sc daily. Patients who undergo procedures that are considered low risk for bleeding complications will resume dalteparin or placebo at 200 IU/Kg s.c. daily.

Outcomes:The primary outcome will be the frequency of episodes of major thromboembolism over a 90-day follow-up period following the time of randomization. Secondary outcomes will include major bleeding and overall survival.

Relevance: To bridge or not to bridge, is a common clinical question, without randomized trial evidence to guide clinicians. This RCT will answer whether post-operative bridging reduces risk of thromboembolism or causes harm.

Eligibility criteria: Inclusion Criteria:

1. Informed consent,
2. Patients aged \>18
3. Patients with prosthetic(mechanical) heart valve
4. Patients with atrial fibrillation or atrial flutter and a major risk factor (previous TIA or stroke, high blood pressure, diabetes, aged \>75, moderate/severe left ventricle dysfunction)
5. Who are receiving long-term oral anticoagulation and require elective non-cardiac surgery or an invasive procedure with reversal of their anticoagulant therapy.

Exclusion Criteria:

1. Evidence of active bleeding within last 30 days prior to stopping warfarin.
2. Platelet count \<100 x 109/L.
3. Spinal or neurosurgery.
4. Life expectancy less than 3 months.
5. Calculated creatinine clearance \<30 ml/min
6. Patients requiring cardiac surgery.
7. Multiple prosthetic(mechanical) valves or Starr-Edwards valve or prosthetic(mechanical) valve with a history of stroke or TIA
8. History of heparin induced thrombocytopenia (HIT)

Primary outcomes:
measure: major thromboembolism
timeFrame: 90 days from randomization
Secondary outcomes:
measure: major bleeding
timeFrame: 90 days from randomization
measure: minor bleeding
timeFrame: 90 days from randomization
measure: a composite of major bleeding and major thromboembolic events
timeFrame: 90 days from randomization
measure: minor thromboembolic events
timeFrame: 90 days from randomization
measure: overall survival.
timeFrame: 90 days from randomization
Other outcomes:
Locations:
city: Halifax
country: Canada
facility: QE II Health Sciences Centre
state: Nova Scotia
city: Hamilton
country: Canada
facility: Hamilton Health Sciences Corporation-General Hospital
state: Ontario
city: Hamilton
country: Canada
facility: Hamilton Health Sciences Corporation-McMaster Site
state: Ontario
city: Hamilton
country: Canada
facility: Hamilton Health Sciences Corporation-Henderson Site
state: Ontario
city: Ottawa
country: Canada
facility: Ottawa Hospital-General Campus
state: Ontario
city: Montreal
country: Canada
facility: SMBD Jewish General Hospital
state: Quebec
city: Hyderabad
country: India
facility: Care Hospital
state: Nampally
city: New Delhi
country: India
facility: Sir Ganga Ram Hospital
Study officials:
affiliation: University of Western Ontario, Canada
name: Michael J Kovacs, MD, FRCPC
role: PRINCIPAL_INVESTIGATOR
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