Summary

efficacy of rivaroxaban was not significantly different and late administration of rivaroxaban showed lower bleeding tendency

Abstract

Introduction

The purpose of this study was 1) to compare the efficacy and safety of mechanical prophylaxis, aspirin and rivaroxaban for post-TKA VTE prophylaxis and 2) to confirm comparable effectiveness of VTE prophylaxis and perioperative hemorrhagic complications according to timing of the initiation of rivaroxaban.

Methods

A total of 105 patients who underwent primary unilateral TKA between July 2013 and January 2015 randomly received either only mechanical prophylaxis(group A, n=30), aspirin 100mg for 6 weeks(group B; n=24), aspirin 300mg for 6 weeks(group C; n=15), or rivaroxaban 10mg for 2 weeks(group D; n=20, group E; n=16). Rivaroxaban prophylaxis was started 24hr after surgery in Group D and was started 72hr postoperatively in Group E. In the first and fourth weeks after surgery, color Doppler ultrasonography was performed on the deep veins of both lower extremities. The following data were recorded for analysis: post-operative drainage amount; hidden blood loss; number of transfusions; post-operative laboratory data including hemoglobin, hematocrit, platelet at 1, 3, and 7 days and Protrombin time(PT) INR, PT(s), aPTT(s) at 3 and 7 days; number of lower limb ecchymoses and wound complication.

Results

There were no significant difference in the incidence of DVT(either on the 1st week or the 4th week) between the five groups. Postoperative 3-day PT INR and PT(s) was significantly higher in the group D compared with the other groups.(p < 0.001). Postoperative 7-day PT INR and PT(s) were significantly higher in the group D and E compared with group C (PT INR; C vs D ; p=0.003, C vs E; p=0.01, PT(s); C vs D; p=0.003, C vs E; p=0.006). Number of transfusions was higher in group E than in group B (25% vs 56.3%; p=0.046). Postoperative wound complications were more common in group D compared with group B (0% vs 14.3%; p=0.033). No significant difference was found in the post-operative drainage amount, hidden blood loss, incidence of lower limb ecchymoses and clinical outcome between the five groups.

Discussion And Conclusion

There were no significant difference in the incidence of DVT between the mechanical prophylaxis and pharmacological prophylaxis including aspirin, rivaroxaban. But, there was overall tendency that rivaroxaban group showed lower incidence of DVT than mechanical prophalaxis and aspirin group.
Rivaroxaban should be carefully administered because of elevating bleeding tendency and increasing wound complications. In this study, even if started late, efficacy of rivaroxaban was not significantly different and late administration of rivaroxaban showed lower bleeding tendency.