Neurointerventional guide sheath.

We read with interest Luzardo et al’s technical note in the December issue of the AJNR. Although we are pleased that the new Envoy 6F guide catheter (Cordis, Miami Lakes, Fla) facilitated a dualmicrocatheter procedure with a single arterial access, it should be noted that this is by no means a new technique. The 6F Envoy guide catheter with an inner diameter of 0.070 inches and outer diameter of 2.0 mm is comparatively new, but we have been using the same approach to perform balloon-assisted coiling with a 5F Shuttle guide sheath (Shuttle-SL; Cook, Bloomington, Ind) for more than 4 years. The 5F Shuttle guide sheath is currently our preferred guide sheath for endovascular management of intracranial aneurysms. The 5F Shuttle guide sheath has an inner diameter of 0.074 inches and an outer diameter of 0.090 inches (2.3 mm). For the purpose of balloon-assisted coil embolization, one could easily pass a compliant balloon catheter such as the HyperForm or HyperGlide (Micro Therapeutics, Irvine, Calif) and a standard 0.010or 0.014-inch microcatheter through the Shuttle. We have used this method for other dual-catheter techniques (eg, temporary proximal balloon occlusion with nondetachable balloon catheters and coaxial coil and foreign body retrieval with the Goose Neck Snare [Microvena, Vadnais Heights, Minn] or the Retriever device [Target Therapeutics/Boston Scientific, Fremont, Calif]). The Shuttle guide sheath is a hydrophilic-coated braided sheath that provides excellent stability during the procedures. It has a soft, radiopaque tip and is kink resistant. Cook’s Shuttle sheaths have 2 inner dilators with the 5F system (0.018 or 0.038 inch), which allows for a better transition between the wire, inner dilator, and sheath. It also comes with a side port, which facilitates contrast injection. In addition, a Tuohy rotating hemostatic valve can be connected to the side port, through which one could pass the Micro Therapeutics balloon catheter facilitating individual control of each microcatheter. Because our patients typically receive anticoagulants, on completion of the procedure we exchange the 5F Shuttle guide sheath for a standard 5F femoral arterial access sheath, which remains sutured in place overnight. We would also like to point out that, at the end of the procedure, the hole in the femoral artery is 5F when a Shuttle is used as opposed to 6F when the Envoy guiding catheter is used. As mentioned in the article, we agree that the use of this technique has resulted in reduced periprocedural risk when compared with separate femoral arterial catheterizations. We have experienced no technical complications with the use of the 5F Shuttle in conjunction with 2 microcatheters.