Two Medical Devices, Two Different Methods
By BARRY MEIER
New York Times Published: September 30, 2009
Both the Edwards and CoreValve heart valves offer a less invasive alternative to surgery. But the devices differ.
The Edwards unit, currently made of stainless steel, is bigger and is deployed when a heart specialist blows up a balloon to position it. By contrast, the frame of the CoreValve unit is made of a so-called memory metal known as nitinol; when it is released, it expands into its original shape, giving structure to the valve. Heart specialists say it is easier to use.
But that advantage may carry costs. A number of CoreValve patients have required a pacemaker implant to restore their heart’s normal rhythm. The problem occurs because the device, as it expands, can press against the part of the heart that controls its rhythm.
There are also concerns about the durability of nitinol, an alloy made from nickel and titanium. The material has long been used in implanted medical devices including coronary stents, the tiny tubes used to prop open clogged veins. But nitinol can be also prone to metal fatigue.
Dr. John R. Liddicoat, the vice president of Medtronic’s structural heart disease business, said he expected the percentage of patients needing pacemakers would come down as doctors were better trained in the valve’s use and as ways of implanting it were improved. He added that the CoreValve had performed well in thousands of European patients and had not experienced durability issues.
F.D.A. officials declined to discuss their talks with Medtronic. But speaking generally, Matthew Hillebrenner, an F.D.A. official, said that the collapse of an artificial heart valve would be “catastrophic.”
For its part, the Edwards device also encountered problems during its development. In 2005, the company stopped an early study after several patients died. The company then revised the implant procedure.
Edwards officials say they do not expect to report results from its current study to the F.D.A. before next year. But analysts say that the trial appears to be proceeding well because the agency recently gave Edwards permission to use the device in about 500 additional patients over the next year.
“The signal to me is that the F.D.A. has a comfort level with the safety of this valve,” said Kristen Stewart, a medical device industry analyst with Credit Suisse .
Michael A. Mussallem, the chairman and chief executive of Edwards, said that his company hoped to start human trials later this year of an improved valve, which he said was as easy to implant as the CoreValve unit. The next step, he said, would be starting a study sometime in the next year or two involving patients who are now candidates for open-heart surgery.
“The idea of going into younger patients is the big opportunity,” Mr. Mussallem said.
By BARRY MEIER
New York Times Published: September 30, 2009
Both the Edwards and CoreValve heart valves offer a less invasive alternative to surgery. But the devices differ.
The Edwards unit, currently made of stainless steel, is bigger and is deployed when a heart specialist blows up a balloon to position it. By contrast, the frame of the CoreValve unit is made of a so-called memory metal known as nitinol; when it is released, it expands into its original shape, giving structure to the valve. Heart specialists say it is easier to use.
But that advantage may carry costs. A number of CoreValve patients have required a pacemaker implant to restore their heart’s normal rhythm. The problem occurs because the device, as it expands, can press against the part of the heart that controls its rhythm.
There are also concerns about the durability of nitinol, an alloy made from nickel and titanium. The material has long been used in implanted medical devices including coronary stents, the tiny tubes used to prop open clogged veins. But nitinol can be also prone to metal fatigue.
Dr. John R. Liddicoat, the vice president of Medtronic’s structural heart disease business, said he expected the percentage of patients needing pacemakers would come down as doctors were better trained in the valve’s use and as ways of implanting it were improved. He added that the CoreValve had performed well in thousands of European patients and had not experienced durability issues.
F.D.A. officials declined to discuss their talks with Medtronic. But speaking generally, Matthew Hillebrenner, an F.D.A. official, said that the collapse of an artificial heart valve would be “catastrophic.”
For its part, the Edwards device also encountered problems during its development. In 2005, the company stopped an early study after several patients died. The company then revised the implant procedure.
Edwards officials say they do not expect to report results from its current study to the F.D.A. before next year. But analysts say that the trial appears to be proceeding well because the agency recently gave Edwards permission to use the device in about 500 additional patients over the next year.
“The signal to me is that the F.D.A. has a comfort level with the safety of this valve,” said Kristen Stewart, a medical device industry analyst with Credit Suisse .
Michael A. Mussallem, the chairman and chief executive of Edwards, said that his company hoped to start human trials later this year of an improved valve, which he said was as easy to implant as the CoreValve unit. The next step, he said, would be starting a study sometime in the next year or two involving patients who are now candidates for open-heart surgery.
“The idea of going into younger patients is the big opportunity,” Mr. Mussallem said.
