Aneurysmal pressure changes with nondetachable balloon placement and fluid infusion: rationale for liquid embolization

Abstract

Background and purpose: To improve the safety and efficacy of liquid embolization, we evaluated changes in pressures in experimental aneurysms.

Methods: We created three replicas of a lateral sidewall aneurysm and placed them in a physiologic flow circuit. A 3 x 10-mm nondetachable balloon was positioned in the parent vessel across the aneurysmal neck. Intra-aneurysmal pressures were measured at baseline and after balloon inflation. Fluid was infused into the sac via a 1.45F microcatheter during inflation, and maximal pressures were noted. Measurements were repeated eight times in each aneurysm.

Results: After balloon inflation, average intra-aneurysmal pressures increased: 12 mm Hg (13%, sigma(n - 1) = 0.46) for aneurysm 1 (baseline mean arterial pressure [MAP], 94 mm Hg), 15 mm Hg (58%, sigma(n - 1) = 0.88) for aneurysm 2 (baseline MAP, 26 mm Hg), and 15 mm Hg (58%, sigma(n - 1) = 0.92) for aneurysm 3 (baseline MAP, 26 mm Hg). During inflation and infusion, pressures increased slightly: 1.1 (0.94%, sigma(n - 1) = 0.64), 1.6 (3.9%, sigma(n - 1) = 1.1), and 1.9 (4.6%, sigma(n - 1) = 1.2) mm Hg for aneurysms 1, 2, and 3, respectively. Despite complete balloon occlusion of the distal aneurysmal neck, a channel between the proximal aneurysmal neck and the parent-vessel lumen persisted along the microcatheter. Fluid exited the sac via this channel, preventing a concomitant, significant increase in pressure during infusion.

Conclusion: Intra-aneurysmal pressure modestly increased with inflation of a parent-vessel balloon across the neck. When liquid was infused into the sac during inflation, further increases were minimal.

Fig 1.

Clear, elastic, silicone replica of a lateral sidewall aneurysm. A, A needle is inserted through the dome, with its tip in the sac to measure intra-aneurysmal pressure. A microcatheter is positioned with its tip in the lumen of the aneurysm. A nondetachable silicone balloon placed in the parent vessel across the aneurysmal neck is inflated, with the use of dyed fluid for visualization. B, Infusion of dyed fluid into the aneurysm sac via the microcatheter during balloon inflation. C, Infused fluid exits the aneurysmal sac along a channel created by the microcatheter between the nondetachable balloon and the wall of the parent vessel; fluid collects in the lumen of the proximal parent vessel.