MULTIDISCIPLINARY APPROACH USING CATHETER DIRECTED MECHANICAL THROMBECTOMY IN TREATMENT OF A PULMONARY EMBOLISM WITH CLOT IN TRANSIT

ABSTRACT

TOPIC Pulmonary Vascular Disease TYPE Fellow Case Reports INTRODUCTION: Clot in transit (CIT) is a term associated with pulmonary embolism (PE) used to describe thrombus found in the right atrium or ventricle on echocardiography. We present a case of CIT treated in a multidisciplinary approach with catheter-directed mechanical thrombectomy. CASE PRESENTATION A 60 year old male with a history of unprovoked PE off anticoagulation presented with dyspnea and syncope. At presentation, he was tachycardic to 130 but normotensive and not hypoxemic. Troponin-I was elevated at 0.06 ng/mL and B type-NP at 96 pg/mL. SARS-CoV-2 PCR was negative. CT angiography revealed extensive acute bilateral PE with increased RV/LV ratio of 1.9. A stat transthoracic echocardiography (TTE) found a dilated right ventricle with severely reduced systolic function, positive McConnell sign, a tricuspid annular plane systolic excursion (TAPSE) < 1cm, and a serpiginous mobile echodensity in the right atrium consistent with a CIT. A stat ultrasound of the legs also revealed extensive deep venous thrombosis in the proximal left femoral vein extending to the popliteal vein. After a multidisciplinary PE response team discussion, the patient was taken emergently to the catheterization lab. Prior to transport, VA ECMO safety lines were preemptively placed to facilitate ECMO initiation in case of decompensation. With the ECMO circuit primed and the ECMO team, cardiac anesthesiologist, and cardiothoracic surgery on standby, the patient underwent percutaneous mechanical thrombectomy utilizing the Inari Flowtriever® system. With adjunctive TTE guidance, the right atrial clot was first extracted in its entirety with no hemodynamic deterioration. This was followed by aspiration of clot from the right and left pulmonary arteries. Pulmonary artery pressures and cardiac index improved, and the procedure ended with placement of an IVC filter. The patient was transferred to the ICU and was started on enoxaparin at 1mg/kg twice a day. He was discharged on day 4 with rivaroxaban. DISCUSSION: CIT is a rare phenomenon with a prevalence rate of around 4% and is considered a medical emergency given its high mortality rate of 25-40%. While treatment guidelines are limited, anticoagulation alone has shown to be insufficient to treat CIT effectively. While there is data supporting the use of catheter directed therapies for PE, data on its use for CIT is scarce but growing. Furthermore, the preparation of advanced support prior in conjunction with the use of catheter directed therapy may be beneficial in case of life-threatening decompensation. CONCLUSIONS: Catheter-directed mechanical thrombectomy may be effective and safe as shown in this case, but requires a team capable of advanced therapies like ECMO and urgent surgical intervention if needed. REFERENCE #1 Otoupalova E, Dalal B, Renard B. Right heart thrombus in transit a series of two cases. Crit Ultrasound J. 2017;9(1)14. doi10.1186/s13089-017-0069-9. REFERENCE #2 Garvey S, Dudzinski DM, Giordano N, Torrey J, Zheng H, Kabrhel C. Pulmonary embolism with clot in transit An analysis of risk factors and outcomes. Thromb Res. 2020 Mar;187139-147. doi 10.1016/j.thromres.2020.01.006. Epub 2020 Jan 10. PMID 31991381. REFERENCE #3 Dhulipala V R, Fayoda B O, Kyaw H, et al. (August 04, 2020) Thrombus in Transit Extract or Dissolve?. Cureus 12(8) e9550. doi10.7759/cureus.9550. DISCLOSURES No relevant relationships by Mara Caroline, source=Web Response No relevant relationships by Eliot Friedman, source=Web Response No relevant relationships by Eric Gnall, source=Web Responseresearch relationship with Inari Please note April,2021 to presen Added 04/29/2021 by Lee Greenspon, source=Web Response, value=Grant/Research Support No relevant relationships by Patrick Ho, source=Web Response