Flow-directed microcatheters for cerebral embolizations using Ethibloc--an in vitro study

We conducted an in vitro performance study to test the flow-directed Spinnaker microcatheter for potential endovascular embolizations with Ethibloc as embolic agent. We performed in vitro testing using 50 Spinnaker 1.8F hydrophilic infusion microcatheters of three different types. As embolic agent, different mixtures of Ethibloc and Lipiodol (E/L 1:1, 1:2, 1:3) were used. In an in vitro setting, each catheter was injected to a maximum of ten times (E/L 1:1, n = 20 catheters; E/L 1:2, n = 20; E/L 1:3, n = 10). In addition, we evaluated the thinner Spinnaker 1.5F microcatheter (165/20, n = 10). Five Spinnaker 1.5F catheters were each injected with a mixture of Ethibloc and Lipiodol (E/L 1:2 and 1:3). When a mixture of E/L 1:1 was used, 9 of 20 (45%) Spinnaker 1.8F microcatheters ruptured distally near the tip of the microcatheter, each during injection nos. 5-9. One Spinnaker 1.8F was distally occluded after the fifth injection. With a mixture of E/L 1:2, 4 of 20 (20%) Spinnaker 1.8F microcatheters ruptured distally, during injection no. 6 (n = 2), 7 (n = 1), and 8 (n = 1). With a mixture of E/L 1:3, all ten Spinnaker 1.8F microcatheters could be injected without any problems. All ten microcatheters of the thinner Spinnaker 1.5F ruptured (10-18 cm proximally to the catheter tip). This in vitro study using the flow-directed Spinnaker microcatheter revealed that microcatheters can rupture. The Spinnaker 1.8F can rupture when a mixture of Ethibloc and Lipiodol 1:1 or 1:2 and more than four injections are used. The Spinnaker 1.8F does not rupture when a mixture of E/L 1:3 is used, or with a mixture of E/L 1:1 or 1:2 and injecting to a maximum of four times. The Spinnaker 1.5F microcatheter is not suitable for embolizations using Ethibloc. For embolizations with Ethibloc we therefore recommend the use of a guidewire-directed microcatheter.