The oral DOAC, rivaroxaban, is a better alternative to subcutaneous enoxaparin for preventing VTE in immobilised patients after non-major orthopaedic surgery, a major study has shown.
In a multinational European study that recruited 3,604 patients at moderate VTE risk after lower limb surgery, treatment with rivaroxaban was associated with a 75% reduction in risk of major VTE compared to enoxaparin.
The use of rivaroxaban for between two weeks to one month was not associated with any increase in major bleeding or other adverse events compared to enoxaparin according to the results from the PRONOMOS study published in the New England Journal of Medicine.
According to the French investigators, their double-blind, randomised controlled trial is the first to compare oral rivaroxaban against subcutaneous enoxaparin in the population of moderate risk patients undergoing non-major orthopaedic procedures such as knee arthroplasty.
Patients were randomised to rivaroxaban 10 mg (1,809 patients) or enoxaparin 4,000 IU (1,795 patients) and had a median of 28 days of reduced mobility.
For the primary outcome of major venous there were four cases in 1,661 patients (0.2%) in the rivaroxaban group and 18 in the 1,640 patients (1.1%) in the enoxaparin group (risk ratio 0.25; 0.09-0.75; p<0.001 for noninferiority; p=0.01 for superiority).
Major bleeding rates were 0.6% and 0.7%, respectively, for the rivaroxaban and enoxaparin groups.
The investigators noted that in trials to support the use of enoxaparin the benefit was mainly seen in a lower incidence of distal DVT, with little or no symptomatic events compared to control.
— Beverley Hunt (@bhwords) March 29, 2020
“In our trial, the superiority of rivaroxaban was driven mainly by a significantly lower incidence of symptomatic events (relative risk, 0.28) … which could reflect the inclusion of patients at higher risk than the patients involved in previous studies. Nevertheless, there is a need to better identify patients who are at high risk for an event and who would benefit most from thromboprophylaxis,” they said
Presenting the results as part of a virtual ACC 2020 meeting, study lead investigator Dr Nadia Rosencher said that unlike the US, most European guidelines recommend that some level of thromboprophylaxis should be given for non-major surgery “but overall there is no agreement on what should be done for the patient population who remains at moderate risk for clots because of being immobilized during their recovery.
“This study represents a major step forward in our treatment of patients after many orthopaedic procedures because it proves that we can more effectively prevent thrombosis with a once-daily oral medication versus a daily injection with the same safety,” she said.