Soft robotic steerable microcatheter for the endovascular treatment of cerebral disorders

Catheters used for endovascular navigation in interventional procedures lack dexterity at the distal tip. Neurointerventionists, in particular, encounter challenges in up to 25% of aneurysm cases largely due to the inability to steer and navigate the tip of the microcatheters through tortuous vasculature to access aneurysms. We overcome this problem with submillimeter diameter, hydraulically actuated hyperelastic polymer devices at the distal tip of microcatheters to enable active steerability. Controlled by hand, the devices offer complete 3D orientation of the tip. Using saline as a working fluid, we demonstrate guidewire-free navigation, access, and coil deployment in vivo, offering safety, ease of use, and design flexibility absent in other approaches to endovascular intervention. We demonstrate the ability of our device to navigate through vessels and to deliver embolization coils to the cerebral vessels in a live porcine model. This indicates the potential for microhydraulic soft robotics to solve difficult access and treatment problems in endovascular intervention.

Mind the gap: A novel endovascular technique to repair a transected vessel

Level one trauma centers experience horrific injuries on a regular basis. Blunt or penetrating trauma causing vascular injuries are treated by surgeons and interventional radiologists. When a blood vessel is completely transected, the ends of the vessel retract and vasospasm occurs as a normal survival response. When this phenomenon occurs, it is sometimes impossible to reattach the two ends of the injured vessel by surgical means and a bypass graft is often required. However, from an endovascular perspective, covered stents can serve as a vascular bypass as well. The limiting factor with an endovascular approach is the ability to successfully gain wire access across the injured vessel. The technique described in this manuscript describes a “rendezvous” method of repairing a transected axillosubclavian artery from a high-speed motorcycle accident using a steerable microcatheter. Initially, multiple failed attempts to cross the injured vessel were encountered despite using a wide variety of conventional guidewires and catheters. A steerable microcatheter was then used to safely and effectively navigate more than 15 cm through soft tissue to the opposite end of the vessel. In this critically ill patient, this technique significantly reduced the procedural time when compared to our previous experiences repairing arterial transections using traditional catheters.

Use of a steerable microcatheter during superselective angiography: impact on radiation exposure and procedural efficiency

Background/purpose To study steerable microcatheter (SM) use in moderate and highly difficult vessel selection compared to conventional pre-shaped microcatheter (CM) use. Material and methods An IRB approved, single institution analysis of 40 complex angiographic procedures with and without superselective microcatheter use during an eight-month period in 2017 was performed. Target vessels were deemed moderate or highly difficult to select based on vessel size, tortuosity, and/or angulation during non-selective initial angiography. Data collected included type of microcatheter used (SM or CM), number of microcatheters and microwires used, procedure time, radiation exposure index (dose area product/DAP), target vessel location, and time to target vessel selection (TTVS; time from device placement to vessel selection). Comparison between the SM and CM groups was performed using Wilcoxon test. Results A SM (SwiftNinja, Merit Medical, South Jordan, UT, USA) was used to select 46 vessels in 20 patients. One or more CMs were used in 20 patients to select 34 vessels. Median TTVS, number of microwires used, total procedure time, and DAP (microGray.m2) were 12 vs. 462.5 s (p < 0.0001), 0 vs. 2 (p < 0.001), and 26,948 vs. 30,904 (p = 0.15) in the SM vs. CM groups, respectively. When adjusted for body mass index (BMI) using a linear model for radiation exposure, patients in the SM group had lower radiation exposure than those in the CM group (p = 0.05). Conclusions Utilization of a steerable microcatheter, without or with a guidewire, leads to easier and faster target vessel selection with shorter procedure times in complex vessel anatomy.