Pulmonary Embolism
A blood clot that travels to and blocks a pulmonary artery in the lungs, a potentially life-threatening emergency. Prevention of thromboembolic events is relevant to several peptide anticoagulants. Bivalirudin's direct thrombin inhibition helps prevent clot formation during interventional procedures.
Technical Context
PE occurs when a thrombus (usually from lower extremity DVT) embolises to the pulmonary arterial circulation, causing ventilation-perfusion mismatch, right ventricular strain, and potentially cardiovascular collapse. Classification by severity: massive (with sustained hypotension/shock — mortality approximately 25-50%), submassive (RV dysfunction without hypotension — mortality approximately 3-15%), and low-risk (no RV dysfunction — mortality <1%). Diagnosis: CT pulmonary angiography (CTPA) is the standard; D-dimer is used to rule out PE in low-probability patients. Treatment: anticoagulation (initial parenteral followed by oral), systemic thrombolysis for massive PE, and catheter-directed therapy for selected submassive cases. Bivalirudin may be relevant in PE patients with concurrent HIT requiring anticoagulation without heparin. The complement of anticoagulant and antiplatelet peptide drugs (bivalirudin, eptifibatide) plays a role in the broader thrombotic disease management landscape.