PB1062 - Tailoring Anticoagulation: Optimizing LMWH in Bridging Strategies After Mechanical Heart Valve Replacement.

Background: Early postoperative anticoagulation after mechanical heart valve replacement (MHVR) is still a matter of debate. Studies have compared unfractionated heparin with low molecular weight heparin (LMWH) at therapeutic or intermediate doses, the latter of which has shown favourable outcomes in terms of thrombosis but with an increased risk of bleeding. Nevertheless, the advantages offered by LMWH, including easier management and shorter ICU stays, contribute to the widespread adoption of this approach.

Aims: To assess the effectiveness and safety of adjusted intermediate LMWH doses based on weight and glomerular filtration (GF). To evaluate the time to achieve an INR on therapeutic range.

Methods: We performed a prospective, single-center observational study including consecutive patients undergoing MHVR. Within 24 hours of the procedure and excluding patients with postsurgical major bleeding, patients were initiated on adjusted intermediate LMWH (enoxaparin, 0.5 mg/kg/12h SC), alongside weight adjusted AVK therapy (acenocumarol, Oral: 0.04 mg/kg/day. The first INR determination was conducted 48 hours later. Baseline patient characteristics, procedure details and incidences of bleeding and thrombotic complications were documented over the subsequent 30 days. Additionally, time to LWHM discontinuation and postoperative length of stay were recorded.

Results: We included 41 patients (57.5±17.7 years, 63.4% men) undergoing MHVR (2 double valve, 10 mitral valve, 29 aortic valve). Mean duration of LMWH treatment was 5.6±3.5 days. Average time to INR on range was 6.9±4.7 days. Mean length of hospital stay was 8.6±4.2 days. Major bleeding (hemopericardium) occurred in 1 patient (2.4%). 1 minor bleeding (mild hematuria) was identified. No thromboembolic complications were clinically detected.

Conclusion(s): Adjusted intermediate LMWH and early initiation of acenocumarol might be a reasonable strategy to minimize bleeding complications without increasing thrombotic risk. Achieving an early INR within therapeutic range might enable a quicker LMWH discontinuation. Larger cohorts comparing both strategies are needed to confirm these results.