The aim of this study was to compare the safety and efficacy of warfarin versus placebo, administered for 6 months, in the prevention of thromboembolic complications after transvenous cardiac devices implantation in high-risk patients.

Venous lesions following cardiac devices implantation are a common complication of transvenous access that may cause disease manifestations and difficulties during reoperations. These lesions tend to develop early, and their incidence decreases gradually within 6 months after device implantation. Ventricular dysfunction and previous transvenous temporary leads ipsilateral to the permanent implant are risk factors identified in a previous study performed at our institution and other risk factors have been reported recently.The usefulness of prophylactic therapeutic strategies to prevent these complications, however,remains unknown. This randomized trial examined the effects of warfarin in the prevention of these complications in high-risk patients. After device implantation, patients were randomly assigned to receive either placebo or warfarin. Periodical clinical and laboratorial evaluations were performed to anticoagulant management. Following the six-month period, every patient was submitted to a digital subtraction venography.

Inclusion Criteria:

• adults patients submitted to first transvenous implant of pacemakers, implantable cardioverter-defibrillator, or cardiac resynchronization therapy devices
• left ventricular ejection fraction ≤0.40 and/or
• previous transvenous temporary leads ipsilateral to the permanent device implant

Exclusion Criteria:

• history of venous thromboembolism
• atrial fibrillation
• coagulopathy or platelet disorder
• malignancy
• gastro-intestinal hemorrhage or active gastro-duodenal ulcer in the past 6 months
• abnormal prothrombin time (PT)or an international normalized ratio (INR) >40%, or treated with oral anticoagulants