A 32-year-old male professional driver with a few days’ dyspnea was admitted to our department. Physical examination revealed a heart rate (HR) of 110 bpm, respiratory rate (RR) of 31/min, and blood pressure (BP) of 114/62 mm Hg. Laboratory tests showed elevated troponin I (0.6 ng/ml; normal value <0.01 ng/ml) and low arterial saturation (SaO2) — 89% despite oxygen supplementation through a mask with a reservoir bag (12 l/min). Computed tomography pulmonary angiography showed a large thrombus burden in both right (RPA) and left pulmonary artery (LPA). Echocardiography demonstrated right ventricular (RV) overload (increased RV/left ventricular [LV] ratio, 1.2) and decreased tricuspid annular plane systolic excursion (TAPSE), 18 mm (Figure 1A).
The Pulmonary Embolism Severity Index indicated intermediate risk (102 points — class III). Initial therapy with low-molecular-weight heparin (LMWH) in a weight-adjusted dose for 24 hours was ineffective, with symptoms worsening (increase of HR and oxygen demand, without hypotension) and further RV failure progression (RV/LV, 1.3; TAPSE, 16 mm). Thus, our institutional Pulmonary Embolism Response Team (PERT) qualified the patient for catheter-directed mechanical thrombectomy (CDMT).
The procedure was performed via right internal jugular venous access obtained with a 12 F vascular sheath. In a first step, selective angiography of RPA and LPA was performed and revealed large central thrombi bilaterally mainly in the RPA and left lobar pulmonary arteries (Figure 1B). Subsequently, a 115 cm CAT12 HTORQ 12 F catheter of the Lightning 12 system (Penumbra, Alameda, CA, US) was inserted (the first use in Poland) through a 90-cm, 12 F Flexor sheath (Cook Medical, Bloomington, IN, US). Several repeated aspirations were performed in branches of the RPA and LPA with separator-wire-facilitated thrombus fragmentation (Figure 1C, E). The procedure resulted in significant bilateral thrombus burden reduction and a drop in mean pulmonary artery pressure from 28 mm Hg to 22 mm Hg, with no complications. However, increased stiffness of the device (due to a larger diameter of the catheter) resulted in worse maneuverability. The periprocedural blood loss was 300 ml. Twenty-four hours after CDMT, the patient’s HR was 84 bpm, RR was 22/min, and SaO2 was 94% on nasal cannula with a flow rate of 3 l/min, respectively. Echocardiography showed significant RV function improvement (RV/LV ratio, 0.9; TAPSE, 24 mm) (Figure 1F), and troponin I decreased to 0.08 ng/ml. LMWH was continued 48 hours after CDMT, and then warfarin was introduced (the patient was diagnosed with antiphospholipid syndrome).
The recent development of advanced endovascular therapies aims to reduce PE-related morbidity and mortality [1, 2]. CDMT involves devices for mechanical thrombus fragmentation and aspiration to quickly relieve the blockage and restore pulmonary blood flow with a subsequent improvement in the hemodynamic status in intermediate or high-risk PE [3, 4]. The key innovations of the novel Lightning 12 system are the new CAT12 catheter, with a large 0.131’’ lumen and angled tip for an additional circumferential sweep, and the lighting control unit with a pressure/flow sensor system and high-frequency valves. These innovations aim to efficiently regulate aspiration and prevent excessive blood loss [5]. Our case showed that CDMT with the use of the Lightning 12 system was well tolerated and effective.
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