In patients whose hearts have malfunctioning bioprosthetic mitral valves, minimally invasive surgery to insert a new valve is associated with lower rates of death or stroke within one year compared to patients who undergo repeated standard mitral valve replacement surgery, according to a study presented at the American College of Cardiology’s Annual Scientific Meeting (ACC.26).
These results suggest that transcatheter valve-in-valve procedures may provide important short-term clinical benefit in selected high-risk patients. However, longitudinal tracking of patient outcomes is essential to better understand the durability and overall role of this approach in clinical practice. ”
Dimitri Siqueira, MD, Principal Investigator and Director of Interventions, Division of Acquired Valvular Heart Disease, Dante Pazzanese Heart Institute, São Paulo
The mitral valve, one of four valves in the heart, controls blood flow from the left atrium (the heart’s upper left chamber) to the left ventricle (the heart’s main pumping chamber). It consists of two flaps of tissue, or lobules, that open to allow blood flow and close with each heartbeat. Severe mitral valve disease can cause heart failure, pulmonary hypertension, and increased risk of blood clots and stroke. Women are more likely to develop mitral valve disease than men.
The standard treatment for severe mitral valve disease is open-heart surgery to repair the mitral valve or replace it with an artificial valve. When replacements are needed, Siqueira said, most patients now choose valves made from animal tissue rather than metal valves, eliminating the need to take lifelong blood-thinning drugs to prevent blood clots from forming on or near the metal valve. However, over time, valves made from animal tissue (from pigs or cows, known as bioprosthetic valves) deteriorate and need to be replaced. Dr. Siqueira estimates that up to 30% of patients will need to undergo mitral valve replacement again after about 10 years, by which time they may be older and have other health issues that increase the risk of open-heart surgery. Studies have shown that less than 1% of patients die after their initial mitral valve replacement surgery, whereas approximately 7% of patients can die from complications from these “do-over” surgeries.
Transcatheter mitral valve-in-valve (mVIV) has emerged as a minimally invasive alternative to repeat mitral valve replacement (rMVR) for patients who cannot undergo repeat open-heart surgery. mVIV surgery uses a long, flexible tube called a catheter to place a new artificial valve inside a patient’s failing valve. However, until now the results of mVIV and rMVR had not been compared in a randomized controlled trial, Siqueira said.
The investigator-led SURVIV trial enrolled 150 patients (mean age 58 years, 72% female) at seven sites in Brazil. Many of the participants had rheumatic valvular heart disease. Rheumatic valvular disease is a common cause of mitral valvular disease in low- and middle-income countries, often leading to valve replacement at a young age and increasing the likelihood of subsequent intervention.
In the United States, the average age for first mitral valve surgery is about 64 years old, and many patients may need revision surgery in their 70s or 80s. In contrast, in Brazil, where rheumatic heart valve disease remains common, patients often undergo their first mitral valve surgery in their 30s or 40s and require a second valve replacement surgery 10 to 15 years later, Siqueira said.
All patients were considered suitable candidates for both open chest surgery and mVIV surgery. Seventy percent had pulmonary hypertension, and 50% had atrial fibrillation, a rapid, irregular heartbeat that increases the risk of blood clots, stroke, and heart failure. About a quarter had already undergone multiple mitral valve surgeries.
Patients were randomly assigned to receive a new mitral valve via either mVIV or rMVR. The study’s primary endpoint was death from any cause combined with disabling stroke at 1 year. Key secondary endpoints included serious complications such as death from heart disease or stroke, major bleeding, and kidney failure.
At 1 year, the primary endpoint occurred in 20.8% of patients assigned to rMVR and 5.3% of patients treated with mVIV. Siquiera said the difference was primarily caused by events that occurred early after surgery. In-hospital mortality was higher in the surgery group (12.5% vs. 0%), reflecting the more invasive nature of reoperation in this population, he said. Acute kidney injury and life-threatening or major bleeding complications were also observed more frequently after surgery, but stroke rates were low in both groups.
This study has several limitations, including its relatively small size and being conducted in a single country, making it difficult to generalize to populations with different clinical characteristics, healthcare systems, or underlying causes of mitral valve disease. Additionally, many of the participants had advanced mitral valve insufficiency associated with rheumatic heart disease, and pulmonary hypertension was common, factors that may increase the risk of surgery. Also, although members of the independent expert panel that judged patient outcomes were blinded, patients and their doctors could not be blinded to the treatment they were receiving. Finally, no data are available regarding long-term outcomes or valve durability for patients treated with mVIV versus standard surgery. The researchers plan to follow the patients in the study for a total of 10 years to answer these questions.
SURVIV was an investigator-initiated study funded by the Dante Pazanese Heart Institute with additional support from Edwards Lifesciences, which manufactured (and donated) the transcatheter valves used in the study.
Dr. Siqueira will present his research, “Re-operation and Transcatheter Valve-in-Valve for Mitral Valve Prosthetic Dysfunction: The SURVIV Study,” on Sunday, March 29th at 4:00 PM CT/4:00 PM UTC in the main tent of the Great Hall.
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American College of Cardiology
