In patients with a poorly functioning bioprosthetic mitral valve in the heart, a minimally invasive procedure to insert a new valve was associated with a lower rate of death or disabling stroke within one year, compared with patients who underwent standard repeat mitral valve replacement surgery, according to a study presented at the American College of Cardiology’s Annual Scientific Session (ACC.26).

“These results suggest that a transcatheter valve-in-valve procedure may offer an important short-term clinical benefit in selected high-risk patients,” said principal investigator Dimytri Siqueira, MD, PhD, chief of interventions in the Acquired Valvular Heart Disease section at the Dante Pazzanese Institute of Cardiology in Sao Paulo. “However, long-term follow-up of patient outcomes is essential to better understand durability and the overall role of this approach in clinical practice.”

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 leaflets, that open to allow blood flow and close with every heartbeat. Severe mitral valve disease can lead to heart failure, high blood pressure in the lungs and an elevated risk for blood clots and stroke. Women are more likely than men to develop mitral valve disease.

The standard treatment for severe mitral valve disease is open-heart surgery to either repair or replace the mitral valve with a prosthetic valve. If replacement is required, most patients now choose to get a prosthetic valve made of animal tissue rather than one made of metal, Siqueira said, to avoid having to take lifelong blood-thinning medication to prevent blood clots from forming on or near a metal valve. Over time, however, valves made of animal tissue (derived from pigs or cows, known as bioprosthetic valves) deteriorate and need to be replaced. Siqueira estimated that up to 30% of patients need to have a repeat mitral valve replacement after about 10 years, at which point they are older and may have other health problems that make open-heart surgery riskier. Studies have shown that about 7% of patients can die of complications from these “redo” surgeries, compared with less than 1% who die after a first mitral valve replacement surgery.

Transcatheter mitral valve-in-valve (mVIV) has emerged as a minimally invasive alternative to redo mitral valve replacement surgery (rMVR) in patients who cannot undergo repeat open-heart surgery. The mVIV procedure involves using a long flexible tube called a catheter to place a new prosthetic valve inside the patient’s poorly functioning one. Until now, however, the outcomes of mVIV and rMVR had not been compared in a randomized, controlled trial, Siqueira said.

The investigator-initiated SURVIV trial enrolled 150 patients (average age 58, 72% women) at seven centers in Brazil. Many participants had underlying rheumatic valve disease, a common cause of mitral valve disease in middle- and low-income countries, which often leads to valve replacement at a younger age and increases the likelihood of subsequent interventions.

In the United States, the average age for a first mitral valve surgery is about 64 years old, and many patients may need a repeat surgery in their 70s or 80s. By contrast, in Brazil, where rheumatic valvular heart disease is still common, patients often undergo their first mitral valve surgery in their 30s or 40s and need a second replacement valve surgery 10 to 15 years later, Siqueira said.

All patients were considered suitable candidates for both repeat open-heart surgery and the mVIV procedure. Seventy percent had high blood pressure in their lungs, while 50% had atrial fibrillation, a rapid, irregular heartbeat that elevates risk for blood clots, stroke and heart failure. About a quarter had already undergone more than one prior mitral valve surgery.

Patients were randomly assigned to receive a new mitral valve via either mVIV or rMVR. The study’s primary endpoint was a composite of death from any cause and disabling stroke at one year. Key secondary endpoints included major complications such as death from heart disease or a stroke, major bleeding and kidney failure.

At one year, the primary endpoint occurred in 20.8% of patients assigned to rMVR and in 5.3% of those treated with mVIV. This difference was largely driven by events occurring in the early postoperative period, Siquiera said. In-hospital deaths were higher in the surgical group (12.5% vs. 0%), reflecting the greater invasiveness of redo surgery in this population, he said. Acute kidney injury and life-threatening or major bleeding complications were also more frequently observed after surgery, while stroke rates were low in both groups.

The study has several limitations, including its relatively small size and that it was performed in a single country—making it less generalizable to populations with different clinical characteristics, health care systems or underlying causes of mitral valve disease. In addition, many participants had advanced mitral valve dysfunction related to rheumatic heart disease, and pulmonary hypertension was common—factors that may increase surgical risk. It was also not possible to blind patients and their physicians to which procedure patients were receiving, although members of an independent expert committee that adjudicated patient outcomes were blinded. Finally, no data are available on long-term patient 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 try to answer these questions.

SURVIV was an investigator-initiated study funded by the Dante Pazzanese Institute of Cardiology, with additional support from Edwards Lifesciences, which manufactures (and donated) the transcatheter valves used in the study.

Siqueira will present the study, “Redo-Surgery Versus Transcatheter Valve-In-Valve for Mitral Bioprosthetic Dysfunction: The SURVIV Trial,” on Sunday, March 29, at 4:00 p.m. CT / 21:00 UTC in the Main Tent, Great Hall.

ACC.26 will take place March 28-30, 2026, in New Orleans, bringing together cardiologists and cardiovascular specialists from around the world to share the newest discoveries in treatment and prevention. Follow @ACCinTouch, @ACCMediaCenter and #ACC26 for the latest news from the meeting.

The American College of Cardiology (ACC) is the global leader in transforming cardiovascular care and improving heart health for all. As the preeminent source of professional medical education for the entire cardiovascular care team since 1949, ACC credentials cardiovascular professionals in over 140 countries who meet stringent qualifications and leads in the formation of health policy, standards and guidelines. Through its world-renowned family of JACC Journals, NCDR registries, ACC Accreditation Services, global network of Member Sections, CardioSmart.org patient resources and more, the College is committed to ensuring a world where science, knowledge and innovation optimize patient care and outcomes. Learn more at ACC.org.