Background: Transvenous retrograde nidus sclerotherapy under controlled hypotension (TRENSH) is a proposed novel concept for endovascular treatment of cerebral arteriovenous malformations (AVMs).
Objective: To assess the experimental hemodynamic feasibility of TRENSH in a pig AVM model.
Methods: We surgically constructed carotid-jugular fistula-type AVM models in 8 pigs. In 5 pigs (group 1) we hemodynamically assessed the AVM through the main arterial feeder (AF) and draining vein (DV) at systemic normotension (Syst(norm)). We then performed retrograde nidus angiography through the DV at progressively deeper levels of hemorrhagic systemic hypotension (Syst(hypo)), and graded and correlated these angiograms with the degree of Syst(hypo). In another 3 pigs (group 2) we correlated the effects of temporary balloon occlusion of the main AF with the angiographic extent of retrograde nidus filling.
Results: In group 1 pigs, the drop in AF pressure correlated strongly (r(2) = 0.93-0.99) with the drop in DV pressure at progressively deeper Syst(hypo). Minimal retrograde nidus filling occurred at Syst(norm). We observed progressively greater extents of retrograde nidus filling as the transnidal pressure gradients fell with deeper Syst(hypo). Near-complete retrograde permeation of the nidus was possible as the transnidal gradients approached 0 mm Hg. As more of the nidus filled, its concurrent emptying was documented through a greater number of DVs. Temporary AF occlusion resulted in improved retrograde nidus filling in all group 2 pigs.
Conclusion: Endovascular TRENSH appears feasible in a pig AVM model. Further experimental investigations of TRENSH are necessary to assess its full potential before future clinical applications.