Bridging therapy to chronic anticoagulant treatment in patients undergoing cardiac surgery: comparison between low-molecular-weight heparin and subcutaneous unfractioned heparin

Background: At present, no clear evidence has been provided regarding the superiority of various heparin regimens as bridging treatment after heart surgery in patients who need chronic anticoagulation. Objectives: Aim of present pilot investigation was to prospectively compare the safety of weight adjusted enoxaparin and subcutaneous unfractionated heparin in patients undergoing valvular heart surgery. Methods: Patients undergoing heart valve surgery were randomized to weight adjusted enoxaparin (group I) or comparable weight adjusted subcutaneous unfractionated heparin (group II) started within 12 hours after ICU admission. As control group in the same period patients undergoing isolated CABG were randomized to either treatment (group III and IV). Hemorrhagic and thromboembolic complications, the need for blood transfusions, total drainage fluid, haemoglobin values and presence and degree of pericardial effusion at discharge were evaluated. Results: 184 patients were included in the study 69 in group I and 115 in group II. Twenty and respectively 49 patients were enrolled in the control groups. Average fluid drainage after 24 hours was similar with the two regimens both in study and control group. A trend towards the need of blood unit transfusion in ICU after starting heparin therapy was higher in patients treated with. s.c. unfractionated heparin vs enoxaparin (40 vs. 30% p<0.05). No thromboembolic events were recorded. Hemorrhagic pericardial effusion requiring surgical drainage was more frequent with unfractionated heparin (7 vs. 1) however all patients went to our observation after treatment withdrawal, usually between 10 and 17 days after surgery and all but one had anticoagulant over dosage (average INR 4.53). In control groups only one patient needed pericardiocentesis. Conclusion: In patients who need prolonged oral anticoagulation hospital bridging treatment with weight adjusted enoxaparin seems as safe as weight adjusted s.c unfractionated heparin with a lower rate of blood transfusion and a lower rate of pericardial effusion and need for pericardial drainage.