Making TAVR Safer: Columbia Interventional Cardiologists Test Embolic Filter Device to Reduce the Risk of Stroke
Researchers at Columbia Interventional Cardiology are working to improve the safety of transcatheter aortic valve replacement, or TAVR, by testing devices that can potentially reduce the risk of stroke and other ischemic events associated with the procedure.
“We’re exploring new ways to protect the brain and body during interventional cardiovascular procedures like TAVR,” explains Tamim Nazif, MD, director of clinical research for Columbia’s Interventional Cardiovascular Care program. “By capturing embolic debris that can become dislodged during transcatheter valve replacement, we hope to provide better protection for all major arteries leading to the brain, kidneys, and lower body.”
Dr. Nazif is co-principal investigator for the Protect the Head to Head (ProtectH2H) study, a prospective, randomized, multicenter study that seeks to demonstrate the safety and effectiveness of the Emboliner embolic protection catheter device. He and his team recently treated the first patient of a planned 500-participant study at 20 centers worldwide.
Aortic Stenosis and Stroke Risk
The aortic valve connects the left side of the heart to the aorta, the main artery, which transports oxygen-rich blood to the body. In aortic stenosis, the leaflets of the aortic valve narrow and stiffen due to a buildup of calcium over time. This narrowing restricts the normal flow of blood and forces the heart to work harder.
“Aortic stenosis is a lethal disease for which there are no medical therapies. It's a mechanical issue with the heart valve that requires the valve to be replaced,” says Dr. Nazif. “Until recently, that meant major open-heart surgery. But because aortic stenosis frequently affects patients in older age groups who are often considered high risk for surgery, there was no viable treatment option for the sickest patients.”
TAVR employs a minimally invasive approach for valve replacement, using a tube called a catheter to access the heart through a large blood vessel, typically in the groin. Wires are used to guide the artificial valve to the heart, where the device is then implanted directly into the diseased aortic valve. Because TAVR eliminates the need for open-heart surgery to implant the new valve, it offers an avenue for treatment for those deemed too high-risk for surgery. “TAVR really revolutionized the field by bringing treatment to many patients who would not have otherwise been treated.” says Dr. Nazif. “And while TAVR was initially approved for high risk patients, the procedure has now expanded to intermediate (PARTNER 2 trial) and low-risk (PARTNER 3) patients.”
However, during both traditional open-heart surgery and TAVR, pieces from the calcified heart valve, blood clots, or other debris can break loose and travel through the arteries toward the brain. This embolic debris may restrict or block blood flow to the brain or other organs, leading to serious and potentially life-threatening ischemic events like stroke. “Columbia was closely involved with TAVR from the very beginning, and even in those early days, stroke was identified as one of the most significant complications,” notes Dr. Nazif. “So we’ve been interested in developing strategies to protect the brain and decrease the risk of stroke and related complications after TAVR.”
Protecting the Brain
Columbia is heavily involved in the development of cerebral embolic protection devices to help address the risk of stroke and other problems resulting from embolic debris released during TAVR. One strategy is to employ a filter that captures the debris before it enters the blood vessels leading to the brain.
“Here at Columbia, Dr. Martin Leon and Dr. Susheel Kodali helped lead the Sentinel trial, which was an early trial of the Sentinel cerebral embolic protection device,” says Dr. Nazif. “That device was subsequently approved and is now used frequently in our clinical practice and elsewhere.”
The Sentinel device helps protect the brain from embolic debris, but it also has some important limitations. “It only protects two of the three major vessels to the brain and does not protect other areas of the body that might be injured, such as the kidneys,” explains Dr. Nazif.
The Emboliner catheter device seeks to address that by using a cylindrical mesh filter that covers the entire aortic arch. It also features an expanding access port that allows the TAVR device and other equipment used during the procedure to pass through without compromising the effectiveness of the filter. “The filter looks almost like a butterfly net,” says Dr. Nazif. “It is designed to spread and fill up the entire aorta. By offering such comprehensive coverage, our hope is that this will more effectively reduce not just strokes but also other complications like kidney injury after TAVR.”
The Protect the Head to Head trial will compare the safety and effectiveness of the Emboliner device with the Sentinel device to determine if the newer design can reduce adverse cardiac and cerebrovascular events and capture additional embolic debris.
Dr. Nazif sees the Emboliner approach as a big step forward for improved outcomes for transcatheter procedures. "This potentially represents a major advance in embolic protection by providing full brain and body protection, leaving no major artery to the brain, kidneys, or lower body unprotected,” he says. “We look forward to the results of this pivotal randomized trial as we seek to bring this exciting new technology to our patients."
Columbia and TAVR
TAVR has been transformational for treating patients with aortic valve disease. By accessing the heart through large blood vessels in the groin instead of a large incision in the chest, it offers patients a number of benefits over traditional surgery, including shorter hospital stays, less pain, faster recovery times, and reduced risk of complications.
Columbia has played an important role in establishing TAVR as a viable alternative to open-heart surgery, having led the landmark Placement of AoRTic TraNscathetER Valve (PARTNER) trial in the early 2000s and the subsequent PARTNER 2 and PARTNER 3 trials. And by working to reduce risks even more through devices like the Emboliner, Columbia is helping move TAVR even further toward providing better outcomes for patients with aortic stenosis.
“From both the patient and physician perspective, stroke, although infrequent, remains one of the most feared and potentially devastating complications of heart valve replacement,” says Dr. Nazif. “Anything we can do to reduce that rate and improve the safety of our patients is important, so I'm tremendously excited to be able to help lead this study and continue Columbia's legacy of leading innovation in this field.”