Comparison of pain and ecchymosis with low-molecular-weight heparin vs. unfractionated heparin in patients requiring bridging anticoagulation after warfarin interruption: a randomized trial

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 cm2 vs. 8.98 cm2; 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.