This clinical trial is focused on studying a condition known as Isolated Subsegmental Pulmonary Embolism (SSPE), which is a type of blood clot that occurs in the lungs. The trial aims to evaluate the effectiveness and safety of two different approaches for managing this condition in patients who are considered low-risk. One approach involves close monitoring, known as clinical surveillance, without the use of blood-thinning medication. The other approach uses a medication called Rivaroxaban, which is a type of anticoagulant or blood thinner, to prevent further clotting. The medication is provided in the form of a film-coated tablet and is taken orally.

The purpose of the study is to compare these two approaches to see which is more effective in preventing further blood clots and ensuring patient safety. Participants in the study will be randomly assigned to either receive clinical surveillance or the anticoagulant treatment with Rivaroxaban. Some participants may receive a placebo, which is a tablet that looks like the medication but does not contain the active ingredient. The study will last for a period of up to 90 days, during which time participants will be monitored for any symptoms of recurrent blood clots, as well as any significant bleeding or other health issues.

Throughout the study, researchers will also assess the overall health and quality of life of the participants, as well as their use of medical resources. The goal is to determine whether clinical surveillance alone is as effective and safe as using anticoagulation therapy with Rivaroxaban for managing low-risk patients with isolated SSPE. This information will help guide future treatment decisions for this condition.