True statement about pulmonary embolism: (A) Prompt heparin therapy will dissolve thrombi, (B) Known risk factors include gastric cancer, AIDS, (C) Most patients manifest dyspnea, pain, hemoptysis, (D) Free floating iliofemoral thrombi are an indication for a caval filter
Answer is B. Unfractionated Heparin UFH anticoagulates by binding to and accelerating the activity of antithrombin, thus preventing additional thrombus formation. UFH is dosed to achieve a target activated paial thromboplastin time (aPTT) of 60-80 s. The two principal indications for inseion of an IVC filter are (1) active bleeding that precludes anticoagulation and (2) recurrent venous thrombosis despite intensive anticoagulation. Ref Davidson edition23rd pg 620