SEATTLE II has been reported in detail.11 From June 2012 to February 2013, 150 patients were enrolled at 22 sites across the US. Eligible patients were required to have proximal PE (filling defect in at least one main or lobar pulmonary artery), be at least 18 years old, a PE symptom duration of 14 days or fewer, and an RV/LV diameter ratio of at least 0.9 on a contrast-enhanced chest computed tomogram (CT). We included patients with massive (defined as syncope, systemic arterial hypotension, cardiogenic shock, or resuscitated cardiac arrest) or submassive (defined as a normotensive patient with PE and evidence of RV dysfunction) PE. Major exclusion criteria were stroke or transient ischemic attack, head trauma, or other active intracranial or intraspinal disease within 12 months; major surgery within 7 days; recent active bleeding from a major organ; hematocrit less than 30%; and systolic blood pressure less than 80 mmHg despite vasopressor or inotropic support.