It depends. In straightforward cases, we are pretty aggressive with starting anticoagulation to prevent re-thrombosis after pulmonary thromboendarterectomy. These patients are started on parenteral anticoagulation (with IV heparin) on POD #0, usually within several hours after arriving in the ICU if...

In general, IV unfractionated heparin should be initiated as soon as possible after surgery, depending on the surgical hemostasis for the large majority of patients. Once the patient is able to take oral medications, the transition should begin. The choice of agent may vary with the patient's antico...