Background: Saddle pulmonary embolism represents a large clot and a risk for sudden hemodynamic collapse. However, the clinical presentation and outcomes vary widely. On the basis of the findings of right heart dysfunction on echocardiograms, computed tomography angiography, or cardiac enzyme elevation, some argue for the use of thrombolytics or catheter thrombectomy even for hemodynamically stable patients.
Objective: To investigate the outcomes and management of patients with saddle pulmonary embolism, including radiographic appearance (estimate of clot burden) and echocardiographic features.
Measurements and Main Results: This study is a retrospective evaluation of all patients with computed tomography angiography positive for pulmonary embolism from June 1, 2004, to February 28, 2009. Two radiologists selected those with saddle pulmonary embolism and evaluated the clot burden score. The clinical information, echocardiography, treatments, and outcomes of these patients were extracted via chart review. Saddle pulmonary embolism was found in 37 of 680 patients (5.4%, 95% confidence interval 4% to 7%) with documented pulmonary embolism on computed tomography angiography. For patients with saddle pulmonary embolism, the median age was 60 yrs and 41% were males. Major comorbidities were neurologic (24%), recent surgery (24%), and malignancy (22%). Transient hypotension occurred in 14% and persistent shock in 8%. One patient required mechanical ventilation. Echocardiography was performed in 27 patients (73%). Right ventricle enlargement and dysfunction were found in 78% and elevated pulmonary artery systolic pressure in 67%. Computed tomography angiography demonstrated a high median pulmonary artery clot burden score of 31 points. The median right ventricle to left ventricle diameter ratio was 1.39. Inferior vena cava filters were placed in 46%. Unfractionated heparin was administered in 33 (87%) and thrombolytics in four (11%). The median hospital length of stay was 9 days. Two of 37 saddle pulmonary embolism patients (5.4%) died in the hospital (95% confidence interval 0.7% to 18%).
Conclusions: Most patients with saddle pulmonary embolism found on computed tomography angiography responded to the standard management for pulmonary embolism with unfractionated heparin. Although ominous in appearance, most patients with saddle pulmonary embolism are hemodynamically stable and do not require thrombolytic therapy or other interventions.