Of PRIMARY Importance: Surgical or Percutaneous Repair for Mitral Regurgitation?
In recent years, surgical replacement and repair and transcatheter edge-to-edge repair have become comparable options to treat primary, degenerative mitral regurgitation in high risk patients. In 2018, estimated data on more than 19,000 MR procedures from the Centers for Medicare and Medicaid Services indicated that surgical replacement comprised 40 percent of all procedures performed, followed by surgical repair at 34 percent and transcatheter repair at 26 percent.
“We certainly need to acknowledge that the practice patterns for mitral regurgitation have changed over the years,” says Isaac George, MD, Surgical Director, Heart Valve Center at NewYork-Presbyterian/Columbia University Irving Medical Center, and Surgical Director, Structural Heart Disease, NewYork-Presbyterian. “Over the last 5 to 10 years, with increasing experience performing transcatheter mitral repair, it is now becoming a frequent procedure for patients with degenerative mitral regurgitation too sick for surgery. Within the last four years, numerous centers have been established with expert interventionalists and surgeons, reinforcing the acceptance of transcatheter repair as an important treatment option. Supporting the transition to the transcatheter approach have been advances in the technology used to image the mitral valve. Three-dimensional reconstruction and multiplanar reconstruction, for example, now enable us to see the mitral valve in a way that surgeons actually see it in the OR.”
The transcatheter approach to mitral valve repair offers a number of benefits to patients, including avoidance of cardiopulmonary bypass and a more rapid recovery…one to two days in the hospital. And the large majority of patients recover with mild regurgitation or less.
“Indeed, the usability, efficacy, and efficiency of transcatheter mitral valve repair have improved significantly,” says Dr. George. “These are typically edge-to-edge procedures, bringing the leaflet edges together with a clip device. These technologies, too, have evolved over the years, and we can achieve very good results with very complex anatomies. Currently, the MitraClip is only approved for patients with leaflet prolapse who are at high risk for surgery, but it's now time to answer the questions on the minds of all of our cardiac colleagues. Can the procedure be performed in younger patients or patients who are lower surgical risk? Can we perform MitraClip effectively with short- and long-term clinical outcomes equivalent to open cardiac surgery to repair the valve? Is the result going to be as durable? Does the procedure result in a change in patient survival? Who are the best candidates…are they low risk, intermediate risk, or high risk?”
PRIMARY Trial: A Call for Answers
“The PRIMARY trial was constructed to try to answer some, if not all, of these questions,” notes Dr. George. “While the use of the MitraClip has increased, outcomes from cardiac surgery repair are still superb across the board. This is a very important trial to address some critically hard questions. When a patient is very high risk and therefore not a surgical candidate, we know that they're going to do very well with MitraClip, so those are not the patients we need answers for. We’re looking at patients who are lower risk, intermediate risk, or maybe the low end of high risk where there is a question about whether performing a percutaneous clip procedure is better than surgery or not.”
The PRIMARY trial is under the aegis of the NIH-funded Cardiothoracic Surgical Trials Network, a consortium of academic medical centers that promotes rigorous scientific investigations of newer surgical techniques, devices, and pharmaceutical and bioengineered products with a goal to improve cardiovascular disease outcomes in adult populations. The PRIMARY trial is a prospective, multicenter, open-label, randomized (1:1 ratio) trial comparing surgical repair to mitral valve transcatheter edge-to-edge repair (TEER) with a commercially approved edge-to-edge mitral repair device. Patients in the study will be 65 years or older with severe primary, degenerative mitral regurgitation who are candidates for both TEER and surgical repair based on anatomical feasibility.
The researchers seek to achieve the following objectives:
- Demonstrate the long-term effectiveness of each procedure
- Define the relationship between adequacy of mitral regurgitation correction at one-year post randomization and longer-term clinical outcomes
- Evaluate patient-centered outcomes, such as quality of life, functional status, and discharge location
With a study start date of January 14, 2022, enrollment for the trial is now underway or will soon begin at 21 sites across the United States and Canada, with an estimated recruitment of 450 participants in up to 75 sites, including locations in Germany and the United Kingdom over the next three years. Martin B. Leon, MD, Director of the Center for Interventional Vascular Therapy at NewYork-Presbyterian/Columbia University Irving Medical Center and Professor of Medicine at Columbia, serves as one of two Study Directors of the PRIMARY trial, along with Joann Chikwe, MD, of Cedars Sinai.
Patients will be followed for a primary endpoint of all cause mortality, valve re-intervention, hospitalizations or urgent visits for heart failure, or the onset of three plus or greater mitral regurgitation as shown by transthoracic echocardiogram, with a minimum follow-up of three years and ongoing follow-up to 10 years.
“Cardiac surgery is still considered standard of care for mitral regurgitation,” says Dr. George. “The PRIMARY trial is expected to demonstrate if there is a place for the transcatheter approach in that discussion and in that strategy. We’re going to have to see what the data shows, but hopefully the trial will provide well-founded criteria to guide us in our decisions about which patients are best suited for a transcatheter approach and those who would do better with surgery.”
Dr. George emphasizes that at NewYork-Presbyterian/Columbia, all patients are evaluated by a comprehensive valve team that includes surgeons, interventionalists, and echocardiographers. “Everyone has a say in the patient’s wellbeing,” says Dr. George. “We have found over the course of many years that a heart team is the best approach to achieving the best patient outcomes.”
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