After total knee implant surgery, a 65-year-old woman complains of calf pain and swelling in the leg from last 2 days. Later she complains of breathlessness and dies suddenly in the ward. What is the probable cause?

PE and DVT occurring after total hip or knee replacement are prevented by giving subcutaneous fondaparinux. Pt with DVT has H/O cramp in the lower calf that persists for several days and becomes more uncomfoable as time progresses. Pt with PE often has the most common history of unexplained breathlessness. - ARDS is being ruled out as the presentation is acute with decrease in PCWP <18mmHg with B/L pulmonary infilteration on CXR - Stroke and MI has no H/O post op. breathlessness and such presentation.