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A
NEW
WAY TO PREVENT
STROKE?
ATLANTA —Percutaneous occlusion of the left atrial appendage may offer a new method to prevent stroke in patients with atrial fibrillation. Among 31 patients who have undergone this procedure, there have been no complications and no strokes throughout six months of follow-up, reported Horst Sievert, MD. “The procedure may become a valuable alternative for those patients with chronic non-rheumatic atrial fibrillation in whom standard anticoagulation therapy is contraindicated or poorly tolerated,” added Dr. Sievert in his address to the American College of Cardiology’s 51st Annual Scientific Session. He is a senior consultant at the Cardiovascular Center of Bethanien Hospital, Frankfurt, Germany. Complete results of the study were published in the April 23 issue of Circulation.
AN
APPENDAGE WITH “NO PURPOSE”
According
to Dr. Sievert and colleagues, previous trials have established
warfarin as an effective treatment for atrial fibrillation.
However, because it is difficult to manage clinically, warfarin
is not used in all eligible patients. By some estimates,
fewer than one third of eligible patients with atrial fibrillation
are currently being treated.
Echocardiographic, surgical, and postmortem studies suggest that among patients with non-rheumatic atrial fibrillation, up to 100% of clots causing stroke form in the left atrial appendage. Dr. Sievert’s team hypothesized that occluding and obliterating the appendage may reduce the risk of stroke. “The left atrial appendage has no purpose,” said Dr. Sievert. “It can be blocked with no disadvantage to the patient.”
PLAATO’S CREED
The new procedure is called percutaneous left atrial appendage transcatheter occlusion (PLAATO®; Appriva Medical, Sunnyvale, California) and consists of an implant and a delivery catheter. The implant is a self-expanding nitinol cage, covered with a polymeric membrane, and ranges in size from 15 to 32 mm in diameter. It has small anchors that protrude through the membrane, both to hold it in place in the mouth of the appendage and to promote a healing response. Patients receive a device that is approximately 20% to 40% larger than is the opening of the appendage once fully expanded.
The researchers selected 31 patients with non-rheumatic atrial fibrillation who had contraindications to warfarin therapy, generally previous gastrointestinal bleeding. All patients were considered at high risk for stroke due to the presence of concomitant diabetes, heart failure, hypertension, a history of transient ischemic attack or stroke, or visualization of a clot in the left atrial appendage by transesophageal echocardiography.
The device was placed successfully in one procedure in 30 of the 31 patients. In one patient, the first procedure was complicated by a hemopericardium that occurred during left atrial appendage access. A second attempt 30 days later was successful with no further complication. A second hemopericardium occurred during a successful implantation (no sequelae). The average procedure time was 92.7 minutes. Four patients had the device removed and exchanged for a different size during the initial procedure without complication.
At one month, transesophageal echocardiography and chest x-ray showed a stable implant position and no evidence of migration, erosion, or encroachment on surrounding structures. The device surfaces facing the atrium appeared smooth and well healed, with no evidence of thrombus.
PRELIMINARY
DATA SUPPORT THE CONCEPT
The researchers
noted that the current study only establishes the feasibility
of this procedure. Larger randomized trials will be required
to establish the long-term safety of the device and continued
protection against stroke. Nevertheless, said Dr. Sievert,
the attraction of the procedure is that it addresses directly
the mechanism of stroke in atrial fibrillation—the
formation of thrombus in the left atrial appendage. “This
initial study supports the concept that implantation of
a mechanical device to occlude the [left atrial appendage]
can be done safely and with relative ease,” the researchers
concluded.
Dr. Sievert and colleagues believe this approach will also be possible for patients who are candidates for warfarin but who do not wish to go on anticoagulation therapy. They noted that more investigation is required to confirm this possibility.
NR
—Susan Jeffrey
Suggested Reading
Sievert H, Lesh MD, Trepels T, et al. Percutaneous left atrial appendage transcatheter occlusion to prevent stroke in high-risk patients with atrial fibrillation: early clinical experience. Circulation. 2002;105:1887-1889.
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