Subtherapeutic low-molecular-weight heparin as a bridge anticoagulation therapy for patients undergoing mechanical valve replacement surgery

  AIM   Patients with mechanical heart valves (MHV) need to discontinue anticoagulation therapy with coumadin during reoperation, and often require bridging with low molecular weight heparin (LMWH) for anticoagulation. The aim of this study was to assess whether subtherapeutic doses of LMWH at bridged anticoagulation (cardiac and non-cardiac) in MHV patients is a safe and effective method.

  METHODS  The patients with mechanical valve replacement who needed reoperation in our hospital from January 1, 2013 to January 1, 2018 were observed and compared with the patients who underwent the same operation at the same time. The valve replacement group, of which the bridging anticoagulation scheme were decided by cardiac surgeons, consisted of 14 cases after aortic mechanical valve replacemen and 33 cases after aortic and metric mechanical valve replacement. The main outcome measures were hospital mortality, intraoperative bleeding, thromboembolism (TE) events or major bleeding (MBE) events within 30 days after bridging anticoagulation.

  RESULTS  During the study period, 47 patients received subtherapeutic doses of LMWH bridging anticoagulation therapy. Compared with the same operation at the same time, there was no significant difference in intraoperative and postoperative bleeding volume. The bleeding volume at the first 24 hours after operation in valve replacement group was significantly different from control group (P < 0.05). There was no TE event in the mechanical mitral valve replacement group and one death in valve replacement group (0.4%). The cause of death was low cardiac output. There was no perioperative death in control groups. One case (3.3%) of hemorrhage occurred in valve replacement group during the study period (within 30 days of bridging anticoagulation). There was no significant difference between the two groups.

  CONCLUSION  Bridging anticoagulation with sub-therapeutic doses of low molecular weight heparin may increase the intropaerative bleeding but not severe complications like TE and MBE which need additional larger studies.