A PROSPECTIVE RANDOMIZED STUDY TO COMPARE THE ANTI-XA ACTIVITY AND BLEEDING COMPLICATIONS OF STANDARD AND REDUCED DOSAGE OF FRAXIPARINE FOR THE PROPHYLAXIS OF POSTOPERATIVE DEEP VEIN THROMBOSIS IN RECTAL CANCER SURGERY

Abstract

Background & Objective: Patients undergoing elective rectal cancer surgery are usually given Fraxiparine based on recommended dosages from Caucasians’ studies (0.2 ml if body weight <50 kg and 0.3 ml if body weight >50 kg) as prophylaxis for deep vein thrombosis (DVT). In our Chinese population, however, a number of cases of severe bleeding complications were observed with this standard dosage regimen. A prospective randomized study was therefore conducted to compare the anti-Xa activity and bleeding complications of this standard regimen and a reduced dosage regimen (0.1 ml if body weight < 50 kg and 0.2 ml if body weight > 50 kg). Methods: 29 patients with rectal cancer (standard : reduced = 14 : 15) were included in this study. Fraxiparine was given 4 hours prior to surgery and blood was taken just before surgery for measurement of anti-Xa activity. Postoperatively the patients were examined clinically for DVT. Perioperative blood loss, transfusion requirements and postoperative bleeding complications were also recorded and analyzed prospectively. Results: The mean anti-Xa activity was significantly higher in the standard dosage group (0.302 u/ml vs 0.219 u/ml, P = 0.029). There was no clinically overt DVT in the two groups. Total perioperative blood loss and transfusion requirements were not different in both groups. However, one patient in the standard dosage group has developed major intraoperative bleeding that necessitated packing and relaparotomy for haemostatsis. This patient finally died of disseminated intravascular coagulopathy. Gross haematuria was also observed in two patients in the standard dosage group. None of the patients in the reduced dosage group had developed any major or minor bleeding complications postoperatively. Conclusion: Fraxiparine as DVT prophylaxis in the Chinese population should be administered at a reduced dosage because it is shown in this study to be as effective as the standard dosage regimen in preventing DVT and yet it is associated with fewer bleeding complications.