Real-Time Magnetic Resonance Imaging–Guided Stenting of Aortic Coarctation With Commercially Available Catheter Devices in Swine

Abstract

Real-time MR imaging (rtMRI) is now technically capable of guiding catheter-based cardiovascular interventions. Compared with x-ray, rtMRI offers superior tissue imaging in any orientation without ionizing radiation. Translation to clinical trials has awaited the availability of clinical-grade catheter devices that are both MRI visible and safe. We report a preclinical safety and feasibility study of rtMRI-guided stenting in a porcine model of aortic coarctation using only commercially available catheter devices. Coarctation stenting was performed wholly under rtMRI guidance in 13 swine. rtMRI permitted procedure planning, device tracking, and accurate stent deployment. "Active" guidewires, incorporating MRI antennas, improved device visualization compared with unmodified "passive" nitinol guidewires and shortened procedure time (26+/-11 versus 106+/-42 minutes; P=0.008). Follow-up catheterization and necropsy showed accurate stent deployment, durable gradient reduction, and appropriate neointimal formation. MRI immediately identified aortic rupture when oversized devices were tested. This experience demonstrates preclinical safety and feasibility of rtMRI-guided aortic coarctation stenting using commercially available catheter devices. Patients may benefit from rtMRI in the future because of combined device and tissue imaging, freedom from ionizing radiation, and the ability to identify serious complications promptly.