Percutaneous removal of pulmonary artery emboli with Hydrolyser catheter in pigs

Objective: To evaluate the efficacy and safety of the Hydrolyser catheter f or percutaneous treatment of massive pulmonary embolism in pigs. Materials and methods: Twelve pigs, each weighing between 55 kg and 89 kg, were used. Radioopaque 9 cm x 0.8 cm and 4.5 cm x 0.8 cm clots, produced by mixing pi g blood with iodinated contrast agent in vacutainers, were injected via the jugular Vein until central pulmonary embolism (main and proximal lobar art eries) was obtained with significant systemic and pulmonary hemodynamic mod ifications. From a femoral approach, the 7-French Hydrolyser thrombectomy c atheter was run over a 0.025-inch (0.64-mm) guide wire to remove the pulmon ary emboli. Hemodynamic, gasometric and angiographic monitoring was perform ed before and after treatment. The procedure's safety and completeness of e mboli removal was assessed by cardiopulmonary autopsy. Results: Three of th e 12 pigs died during embolization. Thrombectomy was therefore performed in 9, and central emboli could be obtained in 7 of the 9. The Hydrolyser coul d be manipulated only in central pulmonary arteries and could aspirate only central emboli in 5 of the 7 pigs that had them. Despite minimal angiograp hic improvement seen in these 5, there was no significant hemodynamic and g asometric improvement after treatment. The procedure induced an increase in free hemoglobin blood levels. Autopsies revealed an average of 2 endotheli al injuries per pig (mainly adherent endocardial thrombi] in both nontreate d (n = 3) and Hydrolyser-treated (n = 9) groups. Conclusion: The Hydrolyser thrombectomy catheter can be promptly positioned and easily steered in cen tral pulmonary arteries. It can be used to partially remove central emboli, but not peripheral pulmonary emboli. Most of the injuries observed may not have been strictly related to Hydrolyser use. The pig might not be a suita ble animal model for treatment of massive pulmonary embolism.