3-month rivaroxaban use safe, effective in patients with isolated DVT

Treatment with rivaroxaban for 3 months leads to a safe and successful reduction of recurrent venous thromboembolism (VTE) risk compared to treatment for 6 weeks in patients with isolated distal deep vein thrombosis (DVT), a study has shown.

“This benefit was mainly driven by [the reduction in] recurrent isolated distal DVT, maintained during the 24-month follow-up, and was consistent among patient subgroups,” the researchers said. “These findings do not apply to patients with cancer-associated isolated distal DVT, who were excluded from the study and should not be extrapolated to other anticoagulant treatments.”

This randomized, double-blind, placebo-controlled trial compared two different treatment durations of rivaroxaban in patients with symptomatic isolated distal DVT at 28 outpatient clinical specializing in VTE. After receiving the standard dose for 6 weeks, 402 patients were randomly assigned to receive either rivaroxaban 20 mg (n=200) or placebo (n=202) once daily for an additional 6 weeks.

Isolated distal DVT was unprovoked in 81 (40 percent) and 86 (43 percent) patients in the rivaroxaban and placebo arms, respectively. Recurrent VTE occurred in 23 (11 percent) and 39 (19 percent) participants, respectively (relative risk, 0.59, 95 percent confidence interval [CI], 0.36‒0.95; p=0.03; number needed to treat, 13, 95 percent CI, 7‒126). [BMJ 2022;379:e072623]

Furthermore, 16 (8 percent) patients in the rivaroxaban arm and 31 (15 percent) in the placebo arm experienced recurrent isolated distal DVT (p=0.02), while seven (3 percent) and eight (4 percent) patients, respectively, had either proximal DVT or pulmonary embolism (p=0.80). Fortunately, major bleeding events did not occur in any cohort.

Anticoagulant treatment

In an earlier meta-analysis, pooled results of studies comparing anticoagulant treatment with no treatment in patients with isolated distal DVT revealed a 50-percent decrease in recurrent VTE without an increase in the risk of major bleeding in those who were managed with anticoagulant compared with no treatment. [J Thromb Haemost 2017;15:1142-1154]

Notably, a 61-percent reduction in recurrent VTE risk was seen in patients treated for 6 weeks or longer compared with those treated for a shorter duration. However, the study designs, patient populations, and outcome definitions were heterogeneous. [Circulation 2001;103:2453-2460; Angiology 2006;57:418-423; N Engl J Med 1995;332:1661-1665; Intern Med J 2015;45:177-182]

“Our large randomized clinical trial confirms the results of this meta-analysis, supporting the need for a treatment duration of more than 6 weeks for patients with isolated distal DVT,” the researcher said. “The extended use of rivaroxaban in patients who uneventfully completed the first 6 weeks of treatment was safe and well tolerated.”

Moreover, such benefit persisted among different subgroups, including patients with muscular vein thrombosis and those with provoked isolated distal DVT.

“This is relevant, given the controversy as to whether low risk subgroups should receive anticoagulation and, if so, if they might benefit from shorter treatment durations,” according to the researchers. [Vasc Med 2017;22:518-524; J Thromb Haemost 2017;15:1436-1442; TH Open 2019;3:e58-63]

“Additional investigation is still needed to identify low-risk patients who may not require anticoagulant treatment,” they noted.