A Transcatheter Approach to Congenital Heart Procedures?

Real-time MRI enabled a percutaneous approach to the Glenn procedure in an animal study, which could open a way for children with single-ventricle anatomy to avoid sternotomy and cardiopulmonary bypass.

During the experimental procedure, an MRI antenna-needle was advanced from the superior vena cava to the target pulmonary artery bifurcation. A caval anastomosis and a pulmonary anastomosis could be achieved via balloon-expanded endografts -- or a new self-expanding device designed for this purpose, according to a report published online in JACC: Cardiovascular Interventions.

The total procedure took 78 minutes and the net blood loss was not significant, described Robert J. Lederman, MD, of the National Heart, Lung, and Blood Institute in Bethesda, Md., and colleagues, who called it "the first description of a percutaneous cavopulmonary shunt achieving pulmonary blood flow to both pulmonary artery branches."

With real-time MRI, "continuous anatomic imaging with excellent soft tissue visualization obviated the need for a pre-positioned distal target balloon, snare, or catheter," they noted.

MRI-guided procedures also lack ionization radiation, which is of particular concern in pediatric patients, according to Dara L. Kraitchman, DVM, PhD, of Johns Hopkins University in Baltimore, and Christopher M. Kramer, MD, of University of Virginia Health System in Charlottesville.

"A final advantage of MRI is the ability to assess the patency of the procedure by measuring flow during and after the procedure non-invasively using velocity encoding techniques rather than placing flow wires or using ultrasound," the pair wrote in an accompanying editorial.

Kraitchman and Kramer praised the authors for making "incredible strides in device development and MRI interface guidance systems for a practical approach to a challenging minimally invasive procedure."

"The final challenge will be to convince device manufacturers and pediatric cardiologists to become early adopters of MRI-guided procedures to transform the almost 7 decades of experience with Glenn and hemi-Fontan procedures to a less invasive approach," they concluded.

Lederman's study was done with 15 juvenile pigs who underwent transcatheter cavopulmonary anastomosis and shunt creation under MRI. All survived the procedure without complications.

Patent shunts were established with bidirectional pulmonary artery blood flow, as demonstrated by intra-procedural real-time MRI, post-procedural MRI, x-ray angiography, computed tomography, and necropsy.