SESSION TITLE: Medical Student/Resident Pulmonary Vascular Disease Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Pulmonary embolism (PE) represents a mechanical obstruction of one or more branches of the pulmonary vasculature, usually due to a blood clot. Saddle PE lodges at the bifurcation of the main pulmonary artery, often extending into the right and left main pulmonary arteries. Approximately 3 to 6 percent of patients with PE present with a saddle embolus. We report an atypical case of asymptomatic large saddle PE with normal right heart function. CASE PRESENTATION: A 47-year-old male with history of diabetes, OSA, hypertension, obesity and family history of Factor V Leiden mutation presented with 1-day history of progressively worsening left leg pain and swelling. He denied any fevers, chills, SOB, cough or palpitations, recent surgery, or long car rides. On physical examination, the patient was comfortable, alert and oriented, afebrile, respiratory rate 21/minute, saturating 97% on room air. Laboratory workup was insignificant. EKG showed sinus tachycardia. Venous scan of left lower extremity revealed subacute deep venous thrombosis (DVT) involving the left femoral and popliteal veins. CT pulmonary angiography (CTPA) revealed extensive bilateral pulmonary emboli with large saddle. 2D ECHO revealed normal left ventricle (LV) systolic function with ejection fraction >55% and normal right ventricle (RV) size and function. Patient was started on heparin drip and switched to Eliquis. He was discharged home in a stable condition. DISCUSSION: Saddle PE is a radiologic definition and refers to thrombus that straddles the bifurcation of the pulmonary artery trunk. Saddle PE is found in 2.6% to 5.4% of patients with PE.1,2 Patients with saddle PE presented more frequently with concurrent DVT on hospital admission (75%).3 The presenting symptoms are dyspnea (72%), syncope (43%). Our patient presented with progressive left leg swelling and pain with DVT and no respiratory symptoms. Alkinj et al in 20172 had reported that 18% of patients with saddle PE had normal RV systolic function. One third patients had hemodynamic instability fulfilling the definition of massive PE unlike in our patient. Our patient was hemodynamically stable and had normal RV function, the risk of bleeding outweighed the benefits of fibrinolytic therapy, therefore this patient was managed with conventional treatment. CONCLUSIONS: Despite looking sinister in appearance on imaging studies, patients with saddle pulmonary embolus may be nearly asymptomatic, hemodynamically stable and can be successfully managed with conventional treatment. Reference #1: Ryu JH, Pellikka PA, Froehling DA, Peters SG, Aughenbaugh GL.Saddle pulmonary embolism diagnosed by CT angiography: frequency,clinical features and outcome. Respir Med. 2007;101(7):1537-1542. Reference #2: Alkinj B, Pannu BS, Apala DR, Kotecha A, Kashyap R, Iyer VN. Saddle vs Nonsaddle Pulmonary Embolism: Clinical Presentation, Hemodynamics, Management, and Outcomes. Mayo Clin Proc. 2017;92(10):1511-1518. Reference #3: Girard P, Musset D, Parent F, Maitre S, Phlippoteau C, Simonneau G. High prevalence of detectable deep venous thrombosis in patients with acute pulmonary embolism. Chest 1999;116:903-8. DISCLOSURES: No relevant relationships by Salil Avasthi, source=Web Response No relevant relationships by DEEPTI AVASTHI, source=Web Response No relevant relationships by Rathnavali Katragadda, source=Web Response No relevant relationships by Shanti Pittampalli, source=Web Response