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Though the Lariat device can be used to tie off a part of the heart that raises stroke risk, it has not been approved by the U.S. Food and Drug Administration for this specific purpose. And a small number of atrial fibrillation patients have needed lifesaving surgery or died following this off-label procedure, the study authors discovered.
"We found a handful of deaths, and a greater handful in which there was the need for an urgent open-heart surgery to correct a problem" involving bleeding or damage done to the heart during the procedure, said lead researcher Dr. Jay Giri. He is an assistant professor of cardiovascular medicine with the Perelman School of Medicine at the University of Pennsylvania, in Philadelphia.
Former American Heart Association President Dr. Gordon Tomaselli said the Penn researchers, who are calling for a clinical review of the Lariat, have a point about the device.
"It really should be assessed for efficacy and safety for this particular application," said Tomaselli, who is chief of cardiology for Johns Hopkins Medicine in Baltimore.
The manufacturer of the Lariat device, SentreHEART, said it plans to seek FDA permission for clinical trials focused on this off-label use.
"It is important to note that it is not unusual for device manufacturers to obtain marketing authorization for one use, and then subsequently seek additional indications for use," the company said in a statement.
Doctors often use blood thinners to reduce that risk. But some people have other health problems that preclude using the medications, Giri explained, so other treatments have been sought.
These efforts have mainly focused on the left atrial appendage, an ear-shaped muscular pouch located high in the upper left chamber of the heart, Giri said.
"It's been shown that the grand majority of strokes that occur because of atrial fibrillation happen because a small blood clot forms in the left atrial appendage," he said. "It stands to reason if maybe you could get rid of this left atrial appendage, if it didn't exist, then perhaps there would be a lot less risk of having a stroke."
Surgeons have been using the Lariat device to perform such a procedure, and in fact the Lariat seems designed for that very purpose, even though its manufacturers submitted it for FDA approval as a simple suture device, Giri said.
The Lariat uses two magnetic-tipped wires to guide the device's lasso around the left atrial appendage from the exterior of the heart, he said. Surgeons then draw the lasso tight, sealing off that portion of the heart.
In 2006, the company asked for and received FDA approval of the Lariat device under an expedited process meant for new medical devices that are substantially equivalent to existing devices, Giri said. In this case, the Lariat appeared similar to other suturing devices used in minimally invasive surgery.
"It may have looked every bit like just another pre-formed suture. They'd already approved two or three of these," Giri said. "But when you look deeper, it's never really been used for that purpose in any part of the body, except for closing off the left atrial appendage."
Tomaselli said use of the Lariat device is not widespread for heart patients. "In specialized centers that treat atrial fibrillation, when the right patient presents and you feel boxed in by the lack of an appropriate therapy for that patient, that's when someone would turn to the Lariat," he explained.
In its statement, SentreHEART emphasized that the company does not promote, market or advertise the device as a treatment for atrial fibrillation.
In the new study, published online May 4 in the journal JAMA Internal Medicine, the researchers reviewed published reports on the Lariat's use in clamping off the left atrial appendage and an FDA database that tracks medical devices.
The Lariat had an overall success rate of 90 percent.
But the researchers said they also found seven cases of urgent need for cardiac surgery following use of the device, amounting to about 2 percent of the 309 procedures reviewed, and one death.
And the FDA database revealed five deaths and another 23 cases of urgent cardiac surgery resulting from the procedure, the study authors said.
SentreHEART said the study authors did not contact the company, and there is additional evidence that demonstrates the device's safety.
Dr. Paul Varosy, a cardiologist with the University of Colorado School of Medicine, compared the Lariat's approval process to that of the Watchman, another device targeting the left atrial appendage that received FDA approval in March.
The Watchman device is a mesh umbrella that doctors insert through a tube into the left atrium of a patient's heart. The device covers the left atrial appendage and seals it off from inside the heart.
Watchman endured a lengthy review process, including two large-scale clinical trials, before receiving FDA approval, said Varosy, who wrote an editorial that accompanied the Lariat study.
"There is a pretty stark contrast, and I think after many years and great expense we have a pretty clear-cut answer regarding the safety and efficacy of Watchman," Varosy said. "We just don't have any of that for the Lariat device."
People who have already been treated using the Lariat device should not worry, since all of the problems identified by researchers occurred during placement of the lasso, Tomaselli said.
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