A 69-year-old man was admitted to the local hospital due to intermediate-high risk pulmonary embolism (PE) coexisting with a floating thrombus in the right atrium (RA) (Figure 1A and 1B). His past medical history was irrelevant. The patient was initially qualified for systemic thrombolysis (100 mg of alteplase in a 2-hour infusion), along with an infusion of unfractionated heparin (UFH) under activated partial thromboplastin time control. Eight hours after thrombolysis, the patient developed significant sensation loss, weakness on the right side, and motor aphasia. Emergency noncontrast computed tomography (NCCT) of the head revealed an acute left frontal intraparenchymal hemorrhage with surrounding vasogenic edema (Figure 1C). A neurosurgeon disqualified the patient from intervention. UFH infusion was discontinued immediately. The hypertonic 3% saline solution infusion was initiated to reduce intracranial pressure and prevent seizure activity. Several hours later the patient’s condition deteriorated with an increase in heart rate (HR) up to 120 bpm and oxygen demand (SaO2 90% on a face mask with reservoir bag with a flow rate [FR] of 15 l/min), and a drop in blood pressure (BP) to 93/60 mm Hg. Repeated computed tomography pulmonary angiography showed embolization of the RA clot (Figure 1D and 1E) and a head NCCT scan did not show hematoma progression. Our institutional PE response team qualified the patient for immediate catheter-directed mechanical thrombectomy (CDMT).1 Intensive vasopressor therapy with noradrenaline (0.2 µg/kg/min) and dobutamine (6 µg/kg/min) was initiated and the patient was transferred to our center. The procedure was performed via the right common femoral vein access. Pulmonary angiography confirmed extensive bilateral thrombus burden with total occlusion of the interlobar artery (Supplementary material, Figure S1). Subsequently, CDMT with the Lightning 12 system (Penumbra, Alameda, California, United States) was performed in the right and left pulmonary artery branches (Figure 1F). The procedure resulted in remarkable thrombus burden reduction (Supplementary material, Figure S2) and hemodynamic improvement with a change in mean PA pressure from 29 mm Hg to 21 mm Hg, HR 95 bpm, SaO2 94% on nasal cannula with FR 8 l/min, and the patient’s independence of vasopressors within several hours. Low-molecular weight heparin (half dose) was introduced, and the patient was also qualified for the inferior vena cava filter implantation. Twenty-four hours after CDMT he was weaned off oxygen to room air, imaging showed significant right ventricular (RV) function improvement, and troponin I decreased to 0.006 ng/ml (normal value <⁠0.05 ng/ml) (Figure 1G and 1H). The patient was discharged after completion of neurorehabilitation with significant neurologic improvement.

Figure 1. A, B – computed tomography pulmonary angiography (CTPA) showing bilateral proximal pulmonary embolism (arrow) (A) and right ventricular dysfunction with the increased right ventricular-to-left ventricular ratio (42.9 mm/30.9 mm = 1.39) (B); C – noncontrast CT revealing left frontal intraparenchymal hematoma 57 mm × 31 mm × 30 mm in size (arrow); D, E – repeated CTPA showing embolization of right atrial thrombus into the right pulmonary artery with total occlusion of the interlobar artery (arrow) (D) and progression of right ventricular dysfunction with further increase in the right ventricular-to-left ventricular ratio (68.3 mm/35.7 mm = 1.91); F – catheter-directed mechanical aspiration thrombectomy with the Lightning 12 system in the right pulmonary artery branches under angiographic guidance (arrow) with an image of the removed clots; G, H – repeated CTPA showing significant bilateral pulmonary embolism clot burden reduction (arrow) (G) and improvement of the right ventricular overload after the procedure with the reduction of the right ventricular-to-left ventricular ratio (36.2 mm/32.5 mm = 1.11) (H)

Right heart thrombi (RHT) can be detected in approximately 3% of patients with PE, and are regarded as a significant predictor of poor prognosis.2 The optimal management of such patients is still a matter of debate and it includes anticoagulation, systemic thrombolysis, and surgical or transcatheter embolectomy.3-5 In the presented case, thrombolytic therapy was applied and caused the occurrence of intracranial hemorrhage, one of the dreaded complications of thrombolysis. This report aims to highlight the potential for CDMT as a safe therapeutic strategy with a favorable outcome by quick restoration of pulmonary blood flow and RV recovery without rebleeding risk.