to treat an injury and also spends a lot of time on airplanes. the doctor says once someone is diagnosed with a dvt they're treated with blood thinners. if that doesn't work, doctors have to put in a filter to prevent the clot from traveling to the heart. >> it's inserted into the femoral vein and inserted into the vena cava in such a way as to prevent the clot from reaching the heart. it looks like an umbrella. >> reporter: in rare cases open heart surgery is required to remove the clot. >> if this vessel had embolus, you would see the contrast. >> reporter: a spokesperson says she's recovering at home and is being monitored very closely. in a statement williams says she hopes to be back on the court by early summer and doctors say people can recover from a pulmonary embolism quite well. >> serena's been sort of struggling with another injury after winning wimbledon last