Creation of Transcatheter Aortopulmonary and Cavopulmonary Shunts Using Magnetic Catheters: Feasibility Study in Swine

Abstract

Surgical shunts are the basic form of palliation for many types of congenital heart disease. The Glenn shunt (superior cavopulmonary connection) and central shunt (aortopulmonary connection) represent surgical interventions that could potentially be accomplished by transcatheter techniques. We sought to investigate the efficacy of using neodymium iron boron (NdFeB) magnetic catheters to create transcatheter cavopulmonary and aortopulmonary shunts. NdFeB magnets were machined and integrated into catheters. ''Target'' catheters were placed in the pulmonary arteries (PAs), and radiofrequency ''perforation'' catheters were placed in either the descending aorta (DAo) for central shunts or the superior vena cava (SVC) for Glenn shunts. The magnet technique or ''balloon target'' method was used to pass wires from the DAo or the SVC into the PA. Aortopulmonary and cavopulmonary connections were then created using Atrium iCAST covered stents. Magnet catheters were used to perforate the left pulmonary artery from the DAo, thereby establishing a transcatheter central shunt. Given the orientation of the vasculature, magnetic catheters could not be used for SVCto-PA connections; however, perforation from the SVC to the right pulmonary artery was accomplished with a transseptal needle and balloon target. Transcatheter Glenn or central shunts were successfully created in four swine.

First-in-Human Closed-Chest Transcatheter Superior Cavopulmonary Anastomosis

“…Our group and others have explored numerous related preclinical approaches to endovascular bypass over the past decade (12,13,23). The vessel-to-vessel crossing technique was first described by our group (14).…”

“…In animals, our group and others have used needle (12) and radiofrequency perforation (23) for unidirectional “classic” Glenn shunts (SVC solely to the right PA) and more recently the contemporary, and more technically demanding, bidirectional (both PAs) version (13). In post-operative Fontan patient case reports, small pulmonary artery-to-atria fenestrations (24) and medium-sized PA reconnections (25) have been created.…”

“…Ultimately, we were successful in using trans-septal needle puncture aimed at balloon targets, followed by covered stent placement in animals to create a “classic Glenn” or unidirectional cavopulmonary anastomosis (SVC connected exclusively to the right PA and excluding the left PA) (12). More recently, we accomplished transcatheter bidirectional cavopulmonary anastomosis (SVC blood flow distributed to both the right and left PA) using real-time cardiac magnetic resonance imaging guidance in animals (13).…”

Magnetic Resonance Imaging–Guided Transcatheter Cavopulmonary Shunt

“…In animals, x-ray guided aortopulmonary shunts have been created using docking magnets or radiofrequency perforation followed by stent implantation (11,12). In patients, percutaneous palliative Potts (left pulmonary artery–to–descending aorta) shunts have been achieved in adults with end-stage pulmonary artery hypertension, using x-ray guided wire puncture into pre-positioned snare targets followed by endografts (13).…”

“…Two previous reports achieved x-ray guided percutaneous right-sided, unidirectional “classic” Glenn shunts that did not preserve bidirectional pulmonary blood flow. Levi et al (11) used x-ray transseptal needle puncture (from the superior vena cava) aimed at prepositioned pulmonary artery angioplasty balloon “targets” to establish right-sided unidirectional Glenn circulation in 2 animals. Similarly, Schmitt et al (15) used radiofrequency energy to traverse tissue into balloon catheter targets pre-positioned in the right pulmonary artery and establish right-sided, unidirectional Glenn shunts.…”