Changes in Lung Perfusion in Patients Treated with Percutaneous Mechanical Thrombectomy for Intermediate-Risk Pulmonary Embolism



      Current pulmonary embolism treatment options rely heavily on anatomical clot location. However, anatomical location does not necessarily determine adverse outcomes; rather, clinical severity is secondary to the degree of perfusion impairment. Dual-energy computed tomography pulmonary angiogram (DE-CTPA) can map perfusion at the time of pulmonary embolism diagnosis. Single-photon emission computed tomography ventilation-perfusion scans allow for perfusion tracking similar to DE-CTPA.


      We present 3 patients with intermediate-risk pulmonary embolism treated with mechanical thrombectomy using the Inari FlowTriever System (Inari Medical, Irvine, Calif). Lung perfusion scoring was applied to pre-procedure and post-procedure imaging. We graded perfusion of each lobe in 3 planes. If the entire lobe was perfused, a score of 3 was assigned. If lung perfusion is normal, total perfusion score is 15. All patients had pre-procedure and follow-up transthoracic echocardiograms.


      All 3 patients were diagnosed with pulmonary embolism via DE-CTPA that showed right ventricle strain and had deep venous thrombosis. Following mechanical thrombectomy, patients immediately experienced improvement in perfusion score; scores continued to improve at follow-up. All patients also had improvement in right ventricle size or function on follow-up echocardiogram.


      Intermediate-risk pulmonary embolism often has large initial clot burden that predicts residual pulmonary vascular obstruction. Residual pulmonary vascular obstruction is associated with increased risk of death, recurrent thrombus, and chronic thromboembolic pulmonary hypertension. Clot removal via thrombectomy may decrease the prevalence of residual pulmonary vascular obstruction by improving lung perfusion. We found that mechanical thrombectomy increased lung perfusion immediately and at follow-up assessments.



      DE-CTPA (Dual-energy computed tomography pulmonary angiogram), DOAC (Direct oral anticoagulant), SPECT V/Q (Single-photon emission computed tomography ventilation-perfusion), TTE (Transthoracic echocardiogram)
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        • Smith SB
        • Geske JB
        • Maguire JM
        • Zane NA
        • Carter RE
        • Morgenthaler TI
        Early anticoagulation is associated with reduced mortality for acute pulmonary embolism.
        Chest. 2010; 137: 1382-1390
        • Konstantinides SV
        • Meyer G
        • Becattini C
        • et al.
        2019 ESC guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS): the Task Force for the diagnosis and management of acute pulmonary embolism of the European Society of Cardiology (ESC).
        Eur Heart J. 2019; 41: 543-603
        • Fernandes CJ
        • Luppino Assad AP
        • Alves-Jr JL
        • Jardim C
        • de Souza R
        Pulmonary embolism and gas exchange.
        Respiration. 2019; 98: 253-262
        • Ameli-Renani S
        • Rahman F
        • Nair A
        • et al.
        Dual-energy CT for imaging of pulmonary hypertension: challenges and opportunities.
        Radiographics. 2014; 34: 1769-1790
        • Thieme SF
        • Graute V
        • Nikolaou K
        • et al.
        Dual Energy CT lung perfusion imaging–correlation with SPECT/CT.
        Eur J Radiol. 2012; 81: 360-365
        • Picart G
        • Robin P
        • Tromeur C
        • et al.
        Predictors of residual pulmonary vascular obstruction after pulmonary embolism: results from a prospective cohort study.
        Thromb Res. 2020; 194: 1-7
        • Meneveau N
        • Ider O
        • Seronde MF
        • et al.
        Long-term prognostic value of residual pulmonary vascular obstruction at discharge in patients with intermediate- to high-risk pulmonary embolism.
        Eur Heart J. 2013; 34: 693-701
        • Wan T
        • Rodger M
        • Zeng W
        • et al.
        Residual pulmonary embolism as a predictor for recurrence after a first unprovoked episode: results from the REVERSE cohort study.
        Thromb Res. 2018; 162: 104-109
        • Chopard R
        • Genet B
        • Ecarnot F
        • et al.
        Detection of residual pulmonary vascular obstruction by ventilation-perfusion lung scan late after a first pulmonary embolism.
        Am J Cardiol. 2017; 119: 1883-1889
        • Bonnefoy PB
        • Margelidon-Cozzolino V
        • Catella-Chatron J
        • et al.
        What's next after the clot? Residual pulmonary vascular obstruction after pulmonary embolism: from imaging finding to clinical consequences.
        Thromb Res. 2019; 184: 67-76