For two decades, doctors have used a dime-sized plug made by St. Jude Medical Inc. to close holes found in the hearts of stroke victims in a surgery that’s based largely on a medical theory.
This week, they’ll learn if the hypothesis holds up.
New data from two studies testing whether the surgery stops repeat strokes could either cripple sales for the device made by St. Paul, Minnesota-based St. Jude, or send revenue surging. The $20,000 procedure is done in about 9,000 patients a year.
One in five adults are born with the hole, a flap-like opening between the heart’s upper chambers that’s largely symptomless. When found after a stroke, though, some doctors quickly close it under the theory that dangerous blood clots may migrate through the opening and into the brain. In 2010, that thought was challenged by a controversial study that opened a rift among doctors. The newest data, set to be revealed at a medical meeting, has taken from 9 to 12 years to gather.
With positive data “everyone in the world will be looking for patients” to do the surgery in, said Gregg Stone, director of cardiovascular research at New York-Presbyterian Hospital/Columbia University Medical Center for Interventional Vascular Therapy. Negative results “will truly challenge” using the procedure “in any patient.”
The latest studies will be presented at the Transcatheter Cardiovascular Therapeutics conference, which is meeting this week in Miami. One of the trials, dubbed Respect and done in 950 patients over nine years, was paid for entirely by St. Jude. The other, undertaken in Europe with about half as many patients, received an initial grant from the company.
Both trials studied procedures using the St. Jude plug, a device that’s made up of two wire-mesh discs filled with a polyester fabric. The Amplatzer plug, which generates about $100 million a year in sales for St. Jude, is folded into a special catheter and then threaded through a vein in the leg into the section of the heart where the opening is.
Success in preventing repeat strokes in people younger than 60 -- the group in which most unexplained strokes occur -- could create a potential $1 billion market for that device and others, St. Jude’s Chief Executive Officer Dan Starks said in July.
“You’re looking to try to help that patient in any way,” said Stone, who is also co-director to TCT. “Often we close these things without knowing if it’s going to help. These studies will have a major impact on the way we treat this potentially devastating condition.”
St. Jude already has the market leading position for the condition, known as patent foramen ovale, in Europe, said John Heinmiller, the company’s executive vice president, in a telephone interview.
The ultimate goal is to use the findings to file for U.S. approval, which would enable the company to promote the device for the indication, he said. Under U.S. rules, doctors can prescribe a drug or use a device that’s not approved for a certain condition, though companies aren’t allowed to promote unapproved products.
The approach is controversial, and its merits have split interventional cardiologists. The 2010 study, using NMT Medical Inc. (NMTI:US)’s StarFlex, found identical stroke rates among patients previously treated with devices and drugs and no significant differences in other outcomes.
The closure rate was 87 percent and the study included people who had less serious attacks. During the nine years of the 2010 study, about 80,000 patients had had the procedure using the plug, according to an editorial that accompanied the research.
“I was a pretty strong proponent of the procedure previously, but my opinion has changed,” said David Williams, an interventional cardiologist at Brigham & Women’s Hospital in Boston who wasn’t involved in the trials. “The vast majority of people who we have closed for a stroke, a lot of them had a reason for the stroke that wasn’t clear the first time around.”
Williams has performed the procedure on about 80 patients, and hasn’t been able to detect a firm benefit.
He said he no longer “jumps” to operate on stroke patients who were at seemingly low risk for the condition. Instead, he waits to see if something else develops -- an approach that so far has yielded excellent results, he said.
“I would be very surprised if there was a treatment effect for closing someone after a first stroke, especially if they were in an older group, say aged 40 or 50 to 60,” he said in a telephone interview. “For people who are very young, it’s more puzzling. I would consider them for sure.”
Strokes are typically tied to the build-up of fatty plaque in the arteries leading to the brain, hypertension or an erratic heart rate known as atrial fibrillation, said J. Kevin Harrison, director of the catheterization lab at Duke University School of Medicine in Durham, North Carolina. For about 60 percent of those under age 60, however, there is no clear cause, he said.
It’s hard to sit by and wait for a second stroke to develop, he said, giving the example of a 30-year-old first time mother who suffers a stroke hours after giving birth. Complications, if the patient survives, can be devastating.
Patients who elect drug therapy may need warfarin or other blood-thinning therapies for life, he said. While closing the hole might reduce that requirement, the procedure itself can carry rare risks, he said. Because few patients actually have a second stroke -- just 3.1 percent of those in the earlier study -- it’s critical any treatment has few complications, he said.
“The device has to perform perfectly and the risk of implanting it has to be low so you can have an impact on what is already a low-risk event,” said Harrison, an investigator in the Respect study. “This is a fairly daunting trial.”
The potential market for the heart closure device to prevent strokes is about $400 million, said Larry Biegelsen, an analyst at Wells Fargo Securities in New York. He predicts the Respect study will yield positive results and 41,000 of the 800,000 stroke patients in the U.S. each year may qualify for treatment.
The results won’t prove whether or not the strokes are caused by the heart hole, Harrison said. It would make sense, however.
Small clots that would normally travel to the lungs if there was no hole in the atrium may be dissolved by normal enzymes in the bloodstream, he said. That same small clot, if it reaches the cerebral blood vessels, can cause serious damage in the brain.
“The issue was controversial and still remains controversial,” Harrison. “The data out there is imperfect. It’s a scary situation.”
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