Background and aim of the study: The study aim was to determine the safety and feasibility of a standardized bridging regimen in patients with mechanical heart valves at high thromboembolic risk, using low-molecular-weight heparin (LMWH).
Methods: Since the year 2000, all patients at the authors’ institution, with mechanical heart valves and a need for periprocedural interruption of oral anticoagulation (OAC), were prospectively enrolled in this registry. Patients were treated with enoxaparin following a pre-specified, standardized bridging regimen. The main outcome measures were the incidence of hemorrhagic or thromboembolic events. The follow up period was 30 days after hospital discharge.
Results: A total of 116 patients was included (31 with mitral valve replacement, 76 aortic valve replacement, nine double valve replacement). Patients underwent either major surgery (n = 25), minor surgery (n = 36), pacemaker implantation (n = 21), or coronary catheterization (n = 34).

Bridging therapy with enoxaparin was administered for a mean of 7.0 ± 4.6 days. Eighteen patients (15.5%) were treated as outpatients. In 35 patients (34%) with renal impairment (creatinine clearance <50 ml/min), LMWH dosage was halved. No thromboembolic (95% CI 0-3.1%) and only one major bleeding complication occurred (0.86%; 95% CI 0.02-4.7%); minor bleeding occurred in 10 patients (8.6%; 95% CI 4.2-15.3%). The hemorrhages arose after a mean of 5.4 ± 1.4 days LMWH therapy.
Conclusion: Bridging therapy following a standardized LMWH-based regimen with enoxaparin was effective and relatively safe in a large cohort of patients with mechanical heart valves. Extended duration of LMWH therapy seems to promote the incidence of hemorrhage. Neither dose reduction in patients with renal impairment nor outpatient treatment affected the safety and efficacy of this bridging regimen. These findings warrant that more extensive studies be conducted to investigate the safety of this approach.

The Journal of Heart Valve Disease 2007;16:285-292