In the world of cardiovascular medicine, the advent of the transcatheter aortic valve replacement (TAVR) procedure stands as a transformative milestone, rewriting the narrative for people suffering from severe aortic stenosis, a serious condition that narrows the aortic valve in the heart and results in restricting blood flow from the heart to the rest of the body.
Fixing the problem used to require complex open-heart surgeries and prolonged recovery periods. The procedure carried serious risks for patients who were elderly or struggling with other health conditions, and many were ineligible to be treated. Today’s era of minimally invasive treatment began with TAVR two decades ago. Today, nearly 850 TAVR procedures are performed between the Hospital of the University of Pennsylvania, Penn Presbyterian Medical Center, and Chester County Hospital, and Lancaster General hospital each year—making Penn a leader in the region and highly rated by the Society for Thoracic Surgeons and American College of Cardiology’s star rating system.
The beginnings of TAVR
Howard Herrmann, MD, the John Winthrop Bryfogle Professor of Cardiovascular Diseases in the Perelman School of Medicine at the University of Pennsylvania and Health System Director for Interventional Cardiology, has been shaping the TAVR field since its earliest years. His friend Alain Cribier, MD, a French doctor, performed the first successful procedure in April 2002. Recognizing the tremendous potential of the approach, Herrmann visited with Cribier and led the data safety monitoring board as the first surgeries were performed across Europe, working alongside Cribier to analyze how these new devices implanted into the aortic valve were performing. Next, Herrmann put that expertise into participation in the first clinical trials in the field back in the United States.
The first TAVR procedure at the Hospital University of Pennsylvania was performed by Herrmann and his cardiovascular surgery colleagues in 2007. At first, these surgeries were performed only on the most high- risk of patients. Through advanced catheter-based techniques like TAVR, doctors could now deliver a new valve directly to the heart through a blood vessel in the groin or chest area, circumventing the need for invasive procedures. This approach not only reduced the risks associated with traditional surgery but also allowed for quicker recovery times —getting patients back on their feet and enjoying their lives more quickly.
A leader in TAVR research
Howard Herrmann, MD
The field continues to evolve, with Penn Medicine remaining at the center of it all. Herrmann's passion for hemodynamics—the study of blood flow dynamics within the body—drives his commitment to enhancing patient care and outcomes. Hemodynamics play a crucial role in cardiovascular health, influencing factors such as blood pressure, heart rate, and the efficiency of blood circulation. “Understanding hemodynamics is not just a scientific pursuit, but a means of optimizing TAVR procedures to ensure the best possible results for patients,” said Herrmann.
In 2021, Herrmann and a team at Penn began an important study of two different FDA-approved valve devices for severe symptomatic aortic stenosis. The head-to-head trial assessed the safety and performance of the two different valves, targeting patients with small aortic valves—a group that is predominantly women and often underrepresented in clinical trials. With an enrollment of 716 patients across 83 international sites, the SMART Trial aimed to provide crucial insights into valve selection —ensuring each patient gets the right valve for their unique anatomy.
“When it came to clinicians choosing what valve to use, it became a matter of personal preference, as there was no research comparing valves head-to-head yet. I wanted to explore if there were benefits to each respective device, therefore helping tailor our approach when treating patients,” Herrmann said.
The trial was especially important for ensuring that more women could benefit from TAVR. “Women with aortic stenosis are often underdiagnosed, undertreated, and underrepresented in clinical trials, despite experiencing a similar incidence of the condition,” Herrmann said. Despite making up 55 percent of Medicare patients in the U.S., only 45 percent of women with aortic stenosis undergo transcatheter aortic valve replacement. Small aortic annuli are more common in women, so 87 percent of study participants were women.
This month, Herrman and his colleagues published their findings from the trial in the New England Journal of Medicine and presented their data at the American College of Cardiology’s Annual Scientific Session in Atlanta, GA. The trial results identified which valve performed better for patients, which Herrmann says now “allows for the potential of tailored valve selection to enhance long-term patient outcomes in the rapidly evolving landscape of TAVR technology.”
The future of TAVR
With ongoing monitoring of patients in the SMART Trial, insights will continue to emerge and help shape the trajectory of TAVR technology. The recent approval of a third TAVR device in the U.S. proves innovation continues in the field. TAVR, once reserved for high-risk patients, has increasingly been used for lower-risk patients with aortic stenosis. And the work continues: Future research, Herrman says, will address the needs of these low-risk and younger patients, focusing on the durability of these devices and the role of hemodynamics in long-term valve performance.
Through decades of exploration and collaboration, Herrmann has not only expanded understanding of TAVR but has also refined its techniques, ensuring safer and more effective outcomes for patients worldwide. Wilson Szeto, MD, chief of Cardiovascular Surgery at Penn, who has worked alongside Herrman for nearly two decades on this and other transcatheter valve therapy trials, says Herrmann’s continued leadership of the TAVR field ensures that its future is bright. “I have tremendous respect for him as a person as well as a physician. He is a giant in the field,” Szeto said. “His commitment to collaboration and patient advocacy is the key to success of good patient outcomes and advancements in the TAVR field.”