Look at the facts.
Any physician will quickly point out that ventricular septal defects (VSD) are fairly common in newborns — with doctors reporting the defects to be found in 30% of all babies with a congenital heart defect, or two to three for every 10,000 births.
In many cases those holes will close automatically. But what about in other times? What if the affected portion of the heart remains open — perhaps undiscovered — and what if the patient can’t withstand surgery to seal this hole in the heart, once it is discovered?
The answers to both scenarios aren’t pretty and can result in some serious health complications.
AGA Medical (Plymouth, Minnesota) thus far has made its primary goal the closing of a type of hole in the heart called a patent forman ovale (PFO), a remnant of the fetal foramen ovale.
But AGA now can target for U.S. patients a different type of problem, a muscular ventricular septal defect (VSD), with its Amplatzer Muscular Ventricular Septal Defect Occluder.
The company says the device safely fills the hole and treats VSD, a defect in the ventricular septum, the wall dividing the left and the right ventricles of the heart. The ventricular septum consists of “an inferior muscular and superior membranous portion and is extensively innervated with conducting cardiomyocytes,” according to the company’s description of the defect.
The device, which is based off a concept by Kurt Amplatz, MD, one of AGA’s founders, was granted FDA approval last Friday — trailing behind a nearly nine-year use in Europe following granting of the CE mark.
The company says that the device is intended to be used in patients for transcatheter closure in specific circumstances — large-volume left-to-right shunt, pulmonary hypertension and/or clinical symptoms of congestive heart failure. The patient must also be considered at high risk for surgical closure, based either on the anatomy of the defect or the patient’s overall medical condition.
“Typically this device is geared toward infants — those most affected by VSD and who wouldn’t be able to survive heart surgery,” John Barr, COO of AGA, told Medical Device Daily. “We’ve been getting a good response from it in Europe.”
Plans call for immediate roll-out of the device in the U.S.
The Amplatzer Muscular VSD Occluder consists of two discs made of self-expanding nitinol. The device itself is implanted via a catheter, using the percutaneous procedure that contrasts sharply with the alternative of open heart surgery and results in shorter recovery time. It resembles a metal pole with the two discs lining up parallel to one another atop the pole.
“The catheter goes into the heart and the physician releases the device using a screw connection,” Barr said. He added that to increase the closing ability, the discs are filled with polyester fabric that is secured to the disc. The Muscular VSD Occluder uses the Amplazter interface between the device and delivery cable. This screw attachment permits the device to be retrieved and repositioned prior to release from the cable.
As part of conditions for device approval, AGA has agreed to conduct a five-year post approval study to evaluate long-term safety and effectiveness.
In addition, AGA said it will enroll at least 100 patients in a prospective registry study to include an evaluation of post-procedural success, occurrence of major complications, as well as longer term success in closing the shunt associated with the VSD.
Other ongoing AGA initiatives include the Amplatzar PFO closure device, which is currently in a Phase III trial launched last October. In that study, the firm proposes a link between a PFO and migraine headache. (Medical Device Daily, March 6, 2006). The company is also engaged in a study examining the ability of PFO closure to prevent stroke.
Barr told MDD that the company is closing in on completion of its stroke trial, but declined to comment on how many patients were involved in both clinical trial studies for “competitive” reasons. However the company previously has said it was expecting up to 400 patients to participate in the migraine clinical trial study (MDD, July 24, 2007).
AGA’s primary competitor in the sector is NMT Medical (Boston). It also is in trials with its Starflex closure device to test a hypothesis that PFO closure can prevent stroke.
Historically, the commercial PFO market in the U.S. has been small because the only two major players in the sector — NMT and AGA — only had Humanitarian Device Exemptions (HDE).
However, in August of 2006 the FDA asked NMT and AGA to voluntarily remove their HDEs, opening the way to treat many more patients and expected to speed clinical trial enrollment and result in a pre-market approval for PFO closure (MDD, April 24,2007).