Purpose: Repeated administration of low-dose silver nitrate (SN) has been shown to be effective in creating pleurodesis. This study aimed to determine the effectiveness of a SN-eluting pleural catheter for pleurodesis.
Methods: Catheters with a chitosan-SN-hyaluronic acid hydrogel coating designed to release SN over 14 days, or placebo uncoated catheters, were inserted in rabbit and lamb pleurodesis models. Pleurodesis was assessed at 28 days according to a 1-8 point scoring system and pleural fibrosis and inflammation assessed histologically on a 0-4 point scale.
Results: In the rabbit model, pleurodesis scores were significantly increased in both the 24 mg and 50 mg SN catheters versus control animals as well as compared to the contralateral untreated pleural space (median-treated side scores were 5, 8, and 1, respectively, median score for contralateral side was 1 in all groups). In the lamb model, pleurodesis scores were significantly increased in both the 750 mg and 1000 mg catheter groups versus control animals as well as compared to the contralateral untreated pleural space (median-treated side scores were 7, 7, and 1, respectively, median score for contralateral pleural space was 1 in all groups). Catheters appeared well tolerated, although higher than expected mortality was seen in the 50 mg catheter rabbit group.
Conclusions: A catheter designed to deliver SN to the pleural space over 14 days appears to be effective in creating pleurodesis. Further investigations to determine in-vivo catheter pharmacokinetics, toxicity, dose and optimal coating methods are warranted.