Stereotaxis (St. Louis) reported receiving FDA clearance for its magnetically tipped, PowerAssert radio frequency (RF) guidewire for chronic total occlusions (CTOs) in the peripheral vasculature. The guidewire is designed to ablate through CTOs in peripheral arteries.

Traditional manual approaches to percutaneous crossing of CTOs are often hindered by difficulty in controlling the guidewire tip within fully occluded vessels, the company said.

"This is actually a novel, new type of guidewire where we have small magnets embedded in the distal tip of the device that allow the very fine distal tip control, to deliver RF energy at the very tip of the guidewire," Doug Bruce, senior VP for R&D at Stereotaxis, told Medical Device Daily.

Stereotaxis said it is planning a limited clinical introduction of the guidewire to begin later this year, with a broader commercial launch to follow.

The company reported an agreement two years ago with Baylis Medical (Montrael) to develop a magnetically embedded RF guidewire for CTO applications. That agreement included the development of a range of magnetically enabled RF guidewires for both coronary and peripheral CTO crossing applications, Stereotaxis said at the time (Medical Device Daily, Oct. 19, 2006).

"Traditional, manual guidewires used for CTO crossing have little or no steering ability and therefore can only be used with great difficulty in tortuous vasculature, requiring a high level of operator skill and carrying a risk of vessel perforation," said Bevil Hogg, CEO of Stereotaxis.

"Just as the safety, accuracy and efficacy of our Niobe magnetic navigation system have contributed significantly to the treatment of patients with cardiac arrhythmias in the field of electrophysiology, we believe that our PowerAssert RF guidewire will improve the prospects for treating patients with peripheral arterial disease," he said.

Hogg added, "PowerAssert opens a significant new market opportunity for Stereotaxis, underscoring the Niobe system's capabilities as a platform for a broad and growing array of interventional procedures."

Occluded or blocked arteries occur in patients with advanced peripheral arterial disease (PAD), and if left untreated can result in ulcerations and gangrene as well as significantly increased risk of limb loss and death, Stereotaxis noted.

Stereotaxis said its magnetically steerable RF guidewire is designed to ablate through CTOs in peripheral arteries. Its Niobe magnetic navigation system directs the guidewire's distal tip very precisely, allowing for accurate and efficient navigation through difficult-to-treat regions of the peripheral vasculature and CTOs.

Bruce said Stereotaxis has other more conventional guidewires approved for vascular applications, but the PowerAssert RF guidewire is the first that combines magnetic steering with RF energy.

Stereotaxis says its system is designed to enable physicians to complete more complex interventional procedures by providing image-guided delivery of catheters and guidewires through the blood vessels and chambers of the heart to treatment sites. This is achieved, the company says, using computer-controlled, externally applied magnetic fields that govern the motion of the working tip of the catheter or guidewire, resulting in improved navigation, shorter procedure time and reduced X-ray exposure.

The core components of the system have received regulatory clearance in the U.S., Europe, Canada, China and Australia.

The system uses two permanent magnets mounted on articulating and pivoting arms that are enclosed within a stationary housing, with one magnet on either side of the patient table, inside the cath lab. According to Stereotaxis, these magnets generate magnetic navigation fields that are less than 10% of the strength of fields typically generated by MRI equipment and therefore require significantly less shielding, and cause significantly less interference, than MRI equipment.

"The safety and accuracy of the Stereotaxis system has been well documented in electrophysiology procedures, as have its ergonomic advantages and reduction of fluoro exposure," said John Young, MD, director of the cardiovascular innovation program at Ohio State University (Columbus). "With a growing diabetic population and increased prevalence of PAD, I am eager to use the magnetic RF guidewire. This will be the first CTO crossing device that can enable true intra-lesion steering, and I expect it to substantially improve the range of options for CTO treatment."