Warfarin prevents venous obstruction after cardiac devices implantation in high-risk patients: partial analysis.
OBJECTIVES
To evaluate the efficacy of prophylactic use of warfarin in patients with high risk of lead-associated thrombosis.


METHODS
Clinical, prospective, randomized and blinded study, in patients submitted to first transvenous leads implantation with LVEF <0.40 and/or previous ipsilateral temporary pacing. After device implantation, patients were randomly assigned to placebo or warfarin. Periodical clinical and laboratorial evaluations were performed to anticoagulant management. After a six-month period, every patient was submitted to a digital subtraction venography. From February 2004 to November 2006, 101 patients underwent randomization. Baseline characteristics were similar in both groups (P=NS).


RESULTS
Venographic analysis showed 31.4% of venous obstructions in patients assigned to warfarin as compared with 57.1% in patients assigned to placebo (RR= 0.57 [95% CI, 0.33 to 0.98]; P=0.015). In the warfarin group, 72% of the PT/INR tests were in therapeutic INR range. Only one patient required warfarin discontinuation and cross-over to placebo group due to gastrointestinal bleeding.


CONCLUSIONS
These preliminary results showed that the anticoagulation therapy has been safe and reduced the frequency of venous thrombosis after transvenous cardiac devices implantation in high risk patients.