PURPOSE:Twice daily enoxaparin has become the standard of care for treatment of acute deep venous thrombosis (DVT) as a bridge to warfarin in the outpatient setting. The approved dose is 1mg/kg twice daily. Once daily enoxaparin has not been approved for treatment of outpatients with acute venous thromboembolism (VTE). We sought to investigate the efficacy and safety of once daily enoxaparin as a bridge to warfarin for the outpatient treatment of acute VTE.
METHODS:We undertook a case-control study in which we enrolled 40 cases prospectively and matched them to 80 cases. From September 2006 to March 2008, we screened 473 patients with acute VTE. These patients had a confirmed diagnosis of either DVT by venous ultrasound or pulmonary embolism (PE) by chest CT. By using hospital medical records, we matched two controls for each case by age and gender. The controls were also matched by type and location of VTE. All controls had been treated with enoxaparin 1 mg/kg twice daily. For the cases, we prescribed enoxaparin 1.5 mg/kg once daily as a bridge to warfarin. We followed the cases for 30 days. INR levels were monitored. We discontinued enoxaparin after we achieved the target INR between 2.0 and 3.0.
RESULTS:Thirty-seven cases (92.5%) had DVT, and three cases (7.5%) had PE. The average duration of treatment with enoxaparin was 9.2 days for cases. One case (2.5%) and three controls (3.8%) had recurrent venous thrombotic events (p=1.00). There were no bleeding complications in the case group, compared to three (3.8%) in the control group (p=0.55).
CONCLUSION:Once daily enoxaparin, 1.5 mg/kg, as a bridge to warfarin was as effective and safe as twice-daily enoxaparin, 1mg/kg, for initial treatment of acute VTE in the outpatient setting.
CLINICAL IMPLICATIONS:If these results hold up in larger VTE trials, then the dosing frequency of outpatient enoxaparin can be halved without sacrificing efficacy or safety.
DISCLOSURE:Melkon Hacobian, Grant monies (from industry related sources) This study was supported in part, by Sanofi-Aventis (Bridgewater, New Jersey).; No Product/Research Disclosure Information