Pulmonary thromboembolism

OBJECTIVE: To review the pathophysiology, clinical signs, diagnosis, and treatment of pulmonary thromboembolism (PTE) in small animals. DATA SOURCES: Human and veterinary clinical studies, reviews, texts, and recent research in canine and feline PTE diagnosis and thromboembolic therapeutics. HUMAN DATA SYNTHESIS: In humans, clinical probability assessment and point-of-care D-dimer-based algorithms are widely used. Computed tomography pulmonary angiography is the gold standard for PTE diagnosis in humans. Echocardiography is increasingly used for bedside assessment of affected patients. In low-risk human patients anticoagulants alone are recommended while patients with cardiogenic shock are treated with thrombolytics followed by anticoagulation. VETERINARY DATA SYNTHESIS: PTE is associated with numerous predisposing conditions causing hypercoagulability, blood flow stasis, or endothelial injury. Identifying at-risk patients is key to diagnosis in small animals. Thromboelastography provides a method for identifying hypercoagulable patients. Computed tomography pulmonary angiography may replace selective pulmonary angiography as the imaging technique of choice for PTE diagnosis. PTE therapy consists of supportive treatment combined with appropriate, individualized thromboembolic pharmacotherapy for acute treatment and chronic management. Thrombolytic therapy for PTE remains controversial but may be indicated in hemodynamically unstable acute PTE. Thromboprophylaxis in specific conditions is rational although evidence of efficacy is limited. Prognosis depends upon degree of cardiopulmonary compromise and patient response to therapy. Mortality rates in small animals are unknown. CONCLUSIONS: New diagnostic techniques and advances in therapy offer significant potential for improvements in the identification and treatment of PTE in small animals. Further study must be directed to validating new diagnostic modalities and evaluating therapeutic regimes.