Low molecular weight heparin in surgical valve procedures: When and how much for an optimal prophylaxis?

Periprocedural antithrombotic prophylaxis in patients undergoing surgical valve procedures (SVP) is insufficiently investigated. Low molecular weight heparin (LMWH) has been considered as an alternative to unfractionated heparin (UFH). However, safety and efficacy of this prophylaxis strategy is unknown. This study aimed to investigate safety and efficacy of periprocedural LMWH prophylaxis and determine optimal dosage and timing for periprocedural cessation and initiation.

The present study is a retrospective, single-center observational analysis of 388 patients who underwent SVP (valve replacement or valvuloplasty) between 2015 and 2016. In-hospital endpoints were bleeding, transfusions, reoperation due to bleeding, and thromboembolic events.

Giving the first dose of LMWH on the day of SVP was a risk factor for bleeding (OR 1.07; 95% CI 1.04-1.10; p < 0.001), transfusions (OR 1.04; 95% CI 1.01-1.07; p = 0.008) and reoperation due to bleeding (OR 1.20; 95% CI 1.12-1.28; p < 0.001), with > 40 mg/day as a predictor. A higher dosage of LMWH premedication was an independent risk factor for bleeding (OR 1.02; 95% CI 1.00-1.04; p = 0.03) and transfusion (OR 1.03; 95% CI 1.01-1.05; p = 0.01), with > 60 mg/day as a predictor for these events. LMWH dosed within 24 h prior to SVP increased the risk of transfusion (AUC 0.636; 95% CI 0.496-0.762; p = 0.04).

Bleeding is an important early concern after surgical valve procedures. Safety and efficacy of periprocedural prophylaxis with LMWH depends on dosage and the timing of its administration. The most optimal periprocedural prophylaxis in the SVP population appears to be LMWH in dosage of 40-60 mg/day, which is recommended for deep vein thrombosis prophylaxis, ceased at least one day before SVP.