LIMR’s Kowey leads major international report from stroke focus group

Peter R. Kowey, MD, has been a pioneer in cardiology ever since he and his colleagues at a Philadelphia hospital implanted a device 40 years ago that is now the standard of care: the world’s third-ever implantable cardioverter defibrillator.

Kowey, professor for the Lankenau Institute for Medical Research (LIMR), part of Main Line Health, and the man who became the architect of the Lankenau Heart Institute’s world-class cardiovascular program upon his team’s 1990 arrival, has another accomplishment on his lengthy resume, serving as senior author of the initial report from a stroke focus group including some of the top cardiac arrhythmia experts and stroke neurologists across the globe. Kowey co-chairs the group.

“I feel very fortunate to be part of this distinguished panel,” said Kowey, who is the William Wikoff Smith Chair in Cardiovascular Research at LIMR and director of the Division of Cardiovascular Services for Main Line Health. “I believe this report makes a significant contribution to the field, and I look forward to seeing what impact we can make with future white papers. I enjoy being part of this unique group. Its existence is a reflection of the increasing amount of information now available on how heart arrhythmia can cause stroke and the need to diagnose it and to escalate our efforts at prevention.”

“There are only 13 experts in the world on this panel,” said George Prendergast, LIMR president. “For Peter to be among them, let alone serve as one of the two co-chairs and be the senior author of their first report, is a tribute to Peter’s enormous contributions and talents over years in the field of cardiovascular research. It is a real feather in the cap for our institute.”

In the paper, titled "Reexamination of the Embolic Stroke of Undetermined Source Concept." and published in June in the journal Stroke, Kowey and colleagues examined a condition wherein patients without evidence of vascular disease suffer a stroke (embolic stroke of undetermined source, or ESUS). It is a condition caused by clots that travel to the brain, but in which no clear source of the clot is detected.

Experts have established that many of these patients have atrial fibrillation (AF)—a major risk factor for stroke—of which they may be unaware. AF is a rapid and irregular heart rhythm caused by a disruption of normal regular electrical signals. The lack of organized contraction of the top chamber of the heart can cause the blood to clot. When those clots leave the heart and travel to the brain, a large and potentially deadly stroke can result.

Researchers have focused on long-range cardiac monitoring to try to find the arrhythmia in ESUS patients. In addition, two randomized clinical trials involving a total of more than 13,000 patients were conducted wherein patients were given anticoagulants to try to prevent clots rather than trying to first find the AF. The trials, however, showed the approach was no better than administering aspirin.

“Neither trial demonstrated any benefit from empirically taking anticoagulants,” Kowey said. “To us, that clearly means we should look for the arrhythmia and not give anticoagulants unless we find evidence of it. Also, we determined that enhanced criteria are needed to identify stroke patients who might be at highest risk of atrial fibrillation so that we can reduce their risk of a subsequent stroke.”

More than 450,000 hospitalizations with AF as the primary diagnosis happen each year in the United States, according to the U.S. Centers for Disease Control and Prevention. The condition contributes to about 158,000 deaths each year, with the death rate rising for the last two decades. More than 50% of AF patients have no symptoms, making them uniquely susceptible to an unexpected but preventable stroke.

The independent stroke focus group is sponsored by Medtronic, a medical technology company headquartered in Dublin, Ireland. Besides the United States, its membership includes experts from Dubai, Germany, Japan, and the United Kingdom. Gregory W. Albers, MD, director of the Stanford Stroke Center, joins Kowey in co-chairing the group, which has met for the last five years and has an open-ended mandate to continue meeting.