While home treatment of venous thromboembolism has been associated with low failure rates in several studies, in the real-world setting, challenges in arranging follow-up, assuring therapy compliance, and concern about legal ramifications should a discharged patient develop complications have prevented these protocols from becoming the norm.
In a report published in Academic Emergency Medicine, Daren M. Beam, MD, MS, from Indiana University School of Medicine in Indianapolis, Indiana, and colleagues evaluated a novel emergency department–initiated rivaroxaban-based protocol that would allow early home treatment of lower-risk patients with deep-vein thrombosis (DVT) and pulmonary embolism (PE).
"This protocol allows the immediate home treatment of patients with VTE using a target-specific oral anticoagulant that requires minimal laboratory monitoring," Dr. Beam wrote. "[This initial report] demonstrates that patients can be treated at home with rivaroxaban with a low rate of VTE recurrence and low rate of bleeding."
The single-arm protocol was divided into two phases: an emergency department phase, which included the actual VTE diagnosis, and a follow-up clinic phase. Eligible patients were prescribed 15 mg of rivaroxaban twice per day for 21 days, followed by one month of the drug at 20 mg once per day.
In the follow-up phase, one to two days after discharge, a member of the health-care team called the patient to confirm that he or she was able to fill the rivaroxaban prescription and to answer questions about the diagnosis and therapy. The first follow-up visit was approximately three weeks after diagnosis and the second follow-up was three to six month later. Each patient received a standardized history and physical designed to assess bleeding risk, recurrence, and presence or absence of post-thrombotic syndrome.
From March 2013 through April 2014, a total of 106 patients who were determined to be low-risk according to Hestia criteria (a tool used to determine which PE patients are suitable for outpatient treatment) were treated: 71 patients (68%) with a DVT, 30 patients (28%) with a PE, and five patients with both (3%). These numbers represented 51 percent of all DVTs and 27 percent of all PEs diagnosed in both emergency departments during the study period.
"Most had been diagnosed acutely with their first VTE. Abnormal renal function was an exclusion criterion," the authors noted.
Study patients were followed for a mean of 389 days, and all met the target rate of VTE recurrence of â‰¤2.1 percent and a bleeding rate of â‰¤9.4 percent. These targets were chosen based on results from the pooled analysis of the EINSTEIN trial, in which treatment with rivaroxaban was associated with VTE recurrence and bleeding rates of 2.1 percent and 9.4 percent, respectively.
No patient had VTE recurrence, and no patient had a major or clinically relevant bleeding event while on therapy (95% CI=0% to 3.4%). However, three patients had recurrent DVT after cessation of therapy (2.8%; 95% CI=1% to 8%).
"We consider this work to be early, but our initial outcome rates for VTE recurrence (0%) and bleeding (0%) while on therapy align favorably with the respective rates of 2.1 percent and 9.4 percent observed in the pooled EINSTEIN data," the authors concluded.
While this study is strengthened by its use of data from a functioning, real-world referral clinic, the authors did note some limitations, including the biased-by-design patient sample and the fact that outcomes data were determined in part from retrospective analysis of patient charts. In addition, this was a non-comparative study, as there was no control arm of patients treated with other agents or who were admitted to the hospital initially.
"In the opinion of the investigators, adoption by our emergency department faculty and housestaff was rapid and enthusiastic," Dr. Beam and co-authors observed. "We also have preliminary data indicating that patients preferred this approach over conventional treatment with low-molecular-weight heparin–warfarin."
Beam DM, Kahler ZP, Kline JA. Immediate discharge and home treatment with rivaroxaban of low-risk venous thromboembolism diagnosed in two U.S. emergency departments: a one-year preplanned analysis. Acad Emerg Med. 2015;22:789-95.