Mr.-Guided Cardiac Interventions Using Mr.-Safe Passive Devices: A Preclinical Study and First-in-Man Congenital Interventions

Background: Percutaneous cardiac interventions are currently performed under X-ray guidance. Magnetic resonance imaging has been employed to guide intravascular interventions in the past, but mainly in animals. Translation of MR-guided interventions into humans has been limited by the lack of fully MR-compatible and safe devices, such as MR guidewires with mechanical characteristics similar to standard guidewires. The aim of the present study was to evaluate the safety and efficacy of a newly developed MR-safe and compatible passive guidewire in aiding MR-guided cardiac interventions in a swine model and describe the two first-in-man solely MR-guided interventions. Methods and Results: In the preclinical trial, the new MR compatible wire aided the performance of 20 interventions in 5 swine. These consisted of balloon dilation of nondiseased pulmonary and aortic valves, aortic arch and branch pulmonary arteries. Catheter manipulations were monitored with real time MRI sequence with interactive modification of imaging plane and slice position. Following ethics and regulatory authority approval the two first-in-man MR-guided interventions were performed in a child and an adult, both with elements of valvar pulmonary stenosis. Both patients had successful relief of the valvar stenosis and were discharged home a few hours later with no complications. Conclusions: The described pre-clinical study and case reports are encouraging that with the availability of the new MR compatible and safe guidewire, certain percutaneous cardiac interventions will become feasible to perform solely under MR-guidance. The benefits are clear with elimination of the use of ionising radiation and improvement of visualisation of the target lesions.