Optimization of thrombolytic dose for treatment of pulmonary emboli using endobronchial ultrasound-guided transbronchial needle injection.

OBJECTIVE

Severe pulmonary embolism is often managed with thrombolysis. We sought to determine whether endobronchial ultrasound (EBUS)-guided transbronchial thrombolysis remained effective at lower alteplase doses, with the goal of minimizing potential bleeding risk.

METHODS

Yorkshire pigs were anesthetized and ventilated. Preformed autologous blood clots were administered into bilateral pulmonary arteries via EBUS-guided transbronchial injection. After documenting baseline clot sizes, alteplase was injected into the clots using a 25-gauge transbronchial needle and clot dissolution was monitored over 30 minutes. The study was performed in 2 phases. First, alteplase doses of 5 and 12.5 mg were evaluated. These results informed dose selection for the second phase. Results were compared with 25-mg dose data using EBUS from a previous study.

RESULTS

In the first phase, 3 clots were evaluated. Distilled water, 5 mg, and 12.5 mg alteplase were administered. The dissolved clot volume (Vdis) and percentage clot volume loss (Rdis) were -10.9, 111.6, and 160.3 mm, and -1.6%, 11.0%, and 59.3%, respectively. In the second phase, alteplase doses of 5, 10, and 15 mg were evaluated in 12 clots across 6 pigs. The Vdis were 247.5 mm (Rdis, 20.1%), 910.8 mm (Rdis, 80.9%), and 798.3 mm (Rdis, 76.0%) for 5, 10, and 15 mg alteplase, respectively. Remakably reduced performance was observed with 5 mg alteplase versus 10 mg (Vdis: P < .001, Rdis: P < .001), and 15 mg (Vdis: P = .004; Rdis: P < .001). No complications were observed.

CONCLUSIONS

Alteplase doses ≥10 mg were optimal for EBUS-guided transbronchial thrombolysis. This technique might represent an effective alternative therapy for central pulmonary embolism.