An Open-Label Randomized Control Trial of Pre-Operative Low Molecular Weight Heparin Versus Tapered Warfarin as Bridging Therapy for Patients With Implantation of Pacemaker or Defibrillator

Approximately 2 million patients in North America are currently treated with the blood thinner warfarin. These patients have every year more than 200,000 invasive procedures, for which warfarin must be stopped to avoid bleeding complication. To protect the patient against blood clots and stroke while warfarin is stopped, most physicians today order "bridging" with low-molecular-weight heparin (LMWH). This is another blood thinner and it is injected under the skin during 3 days before the procedure. For implantation of pacemaker or defibrillator (27,000/year in Canada) the "bridging" routines vary a lot.The common "bridging" treatment with LMWH for 3 days before pacemaker surgery causes bleeding in the "pocket" where the pacemaker is placed in about 5%. For comparison, patients not on any blood thinners develop this bleeding in 2% after this surgery. "Pocket bleeding" may require evacuation of the blood collection and may cause infection. "Pocket bleeding" is thus a fairly common and clinically important but rarely a dangerous bleeding complication. It is a suitable safety endpoint in a study of "bridging" of blood thinners. LMWH costs $80-120, for which some patients are not covered. They have to be taught self-injection technique or have a nurse come to their home. The main hypothesis is if patients on blood thinners can be managed more conveniently before and after pacemaker surgery, without injections, without increased risk of pocket bleeding.