Thrombolysis of Pulmonary Emboli via Endobronchial Ultrasound-Guided Transbronchial Needle Injection

Abstract Background Endobronchial ultrasound-guided transbronchial needle injection (EBUS-TBNI) is a novel technique for treating peribronchial targets. The aim of this study was to evaluate preliminary feasibility of thrombolysis of pulmonary emboli via endobronchial ultrasound-guided transbronchial needle injection. Methods Yorkshire pigs (30-48kg) were anesthetized and mechanically ventilated. Pre-formed autologous clots were injected sequentially into bilateral lower pulmonary arteries in bilateral models (PE1 and PE2, respectively) or into one side in unilateral models using a 21G EBUS-TBNA needle under EBUS guidance. In the bilateral model, two hours after clot injection either 25mL of tissue-plasminogen activator (t-PA; 1mg/mL) or distilled water (DW) were administered into each embolus via 25G EBUS-TBNA needle. In the unilateral model, 25mg t-PA was administered intravenously (IV). Hemodynamic parameters were monitored continuously, and clot dissolve volume was evaluated by EBUS 30 minutes post-treatment administration. Results All clots (6.1±1.7mL) were successfully injected as documented by EBUS Doppler imaging. Clot injection in the bilateral model (n=6) increased pulmonary arterial pressure (mmHg: Baseline 19.2±5.9 vs PE1: 26.7±9.1, p=0.005 vs PE2 29.9±7.1, p=0.0007). After t-PA TBNI in the bilateral model (n=6), pulmonary arterial pressure at 30 minutes post-injection showed improvement (mmHg: PE2 29.9±7.1 vs post-t-PAt 24.4±3.9, p=0.0283). Treatment with t-PA TBNI demonstrated superior clot dissolution at 30 minutes post-treatment (dissolved mm3: t-PA TBNI 625.4±156.6 vs t-PA IV: 181.6±94.3, p=0.0003 vs DW TBNI 42.5±33.0, p Conclusions EBUS-guided transbronchial thrombolysis may be a feasible approach for treating central pulmonary emboli.