A 70 years old man came with complaint of breathing difficulty with cough for past 6 hours. On examination, pulse rate was 120/min and BP was 80/40 mm of hg. Swelling was also seen in left lower limb. Urgent venous Doppler of left lower limb was performed and revealed left CFV thrombosis. D-dimer assay came out to be positive. CT pulmonary angiogram was performed. Diagnosis is-