Background: Subcutaneous (SC) low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) are safe and efficacious for bridging anticoagulation after warfarin interruption. Although LMWH and UFH are self-administered by >90% of patients, factors that may be important to patients such as differences in pain and ecchymosis have not been explored.
Methods: We randomized 24 patients to receive SC LMWH or SC UFH twice-daily during the perioperative period. Injection associated pain was recorded using a visual analogue scale and area of ecchymosis was measured by digital photography of the injection site on the day of the procedure.
Results: The area of ecchymosis was 2-fold higher with UFH than LMWH (19.4 cm(2) vs. 8.98 cm(2); P = 0.33) and pain was similar with both treatments (115 mm vs. 171 mm; P = 0.25), though neither finding attained statistical significance.
Conclusions: This exploratory study was underpowered to detect differences between the groups. Further studies are needed to reliably compare pain and ecchymosis in LMWH vs. UFH.