This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood, Subject name: Medicine
[{'content': 'Best treatment for massive pulmonary embolism: \nSelect and explain. \nA. Intravenous tissue plasminogen activator, B. Heparin, C. Pulmonary thrombo-embolectomy, D. Low molecular weight heparin + warfarin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A. Intravenous tissue plasminogen activator* Massive pulmonary embolism is best managed by thrombolysis using tissue plasminogen activator.* In case thrombolysis is contraindicated then in these patient fogarty catheter removal of clot in pulmonary artery would be done.* In submassive pulmonary embolism heparin is used. Chronic pulmonary embolism leading to pulmonary- hypertension (known as chronic thromboembolic hypertension) is treated with a surgical Procedure known as a pulmonary thromboendarterectomy', 'role': 'assistant'}]