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High-risk patients treated with the AltaValve system, which employs a novel atrial fixation mechanism, had sustained reductions in mitral regurgitation at 1 year and improved clinical outcomes in an early feasibility study. 

The company hopes the device will make transcatheter mitral valve replacement (TMVR) accessible to more patients, including those who would not be eligible for conventional TMVR.

When Subvalvular TMVR Falls Short

Surgery and guideline-directed medical therapy remain the standard of care for mitral regurgitation, but mitral transcatheter edge-to-edge repair (mTEER) has become a preferred option for patients at high surgical risk or with refractory heart failure. 

However, patients with increased mitral valve gradients, extensive mitral annular calcification, or anatomical variations such as large flail gaps, clefts, or perforations often do not experience reductions in regurgitation with the intervention. In this situation, clinicians may turn to mitral valve replacement. 

But currently available TMVRs rely on subvalvular fixation using rigid anchoring mechanisms such as hooks, barbs, paddles, or tethers, leading to an increased risk of left ventricular outflow tract (LVOT) obstructions. 

This design limits the patient pool to those who have compatible anatomy, with approximately 70% of patients failing to qualify for subvalvular TMVR, mainly due to LVOT obstruction risks, a large mitral valve annulus, or mitral annular calcification. And such valves can also interfere with native mitral valve annular dynamics, according to Konstantinos Voudris, MD, PhD, who presented the results of the AltaValve Early Feasibility Study at the Society for Cardiovascular Angiography and Interventions (SCAI) 2026 scientific sessions.

“For patients who are at high surgical risk and [for whom] transcatheter mitral valve repair is not anatomically feasible, TMVR is being considered,” said Voudris, of the Minneapolis Heart Institute at Abbott Northwestern Hospital. “AltaValve’s atrial fixation system minimizes interaction with the LVOT, leading to higher anatomical acceptance rates and improved hemodynamics.”

Establishing Safety and Feasibility

The AltaValve features a 27-mm bovine pericardium valve caged inside a nitinol stent frame that conforms to the left atrial anatomy and is placed via transseptal delivery. 

"It allows for repositioning, as well as recapture at multiple stages, or even after full deployment," Voudris said. 

Voudris' team assessed the device's safety in 30 participants who were considered high-risk for mortality at multiple sites in Europe, the US, and Japan. The patient group was 63% women with an average age of 77 years. Eighty percent had New York Heart Association (NYHA) class III or IV heart failure, including patients with functional and degenerative mitral valve regurgitation. Of those, 23% had moderate-to-severe mitral annular calcification. Twenty-nine patients successfully completed the TMVR procedure and one converted to surgery. 

Voudris noted at the beginning of the study researchers used transapical delivery to place the valves for the first 13 patients and subsequently switched to transseptal delivery. 

Promising Outcomes

"There was excellent reduction in mitral regurgitation grade, with excellent valve hemodynamics," Voudris said, adding that all patients began with severe mitral regurgitation. All patients had none or trace regurgitation immediately postprocedure, and 95% maintained mild or trace regurgitation at 1 year. 

At 1 year, all-cause death occurred in 5 of 13 patients who underwent transapical delivery and 2 of 16 patients who underwent transseptal delivery. Cardiac death occurred in 4 of 13 patients in the transapical group, while none occurred in the transseptal group. No patients required another mitral valve intervention during the 1-year follow up, and researchers did not see any new-onset atrial fibrillation or stroke in either group.

Also at 1 year, 21 of 22 remaining patients had milder NYHA class I or II heart failure, and reductions in mitral valve regurgitation were sustained, while at the beginning of the study all 30 patients had severe regurgitations. "Overall, this translated to better functional capacity for the patients and improved 6-minute walk test ability at 1 year in the full cohort as well as for the transseptal patients only," Voudris said. 

AltaValve’s manufacturer, 4C, has already begun a pivotal trial , ATLAS, involving about 450 patients with NYHA class II to IV heart failure and moderate-to-severe mitral regurgitation despite optimal guideline-directed medical therapy. These patients are unsuitable for surgery and transcatheter edge-to-edge repair. That trial is currently enrolling globally.

Questions Remain

“The AltaValve has been a potentially exciting device due to the limitations of current options including devices that are in phase 3 randomized controlled trials,” said Faisal Rahman, MD, an assistant professor and director of cardiogenic shock at Johns Hopkins University School of Medicine. “I am very impressed with the significant reduction in NYHA class. For a group that may not have had any treatment options, such significant improvement is good to see.”

Rahman, who was not involved in the early feasibility study, cautioned that many questions remain unanswered, such as what to do when the AltaValve fails and the patient requires another mitral valve replacement, whether there is a higher risk of infection, and what the long-term effects might be on right atrial function. 

“Many of these will become clearer with future studies and ongoing follow-up,” Rahman said.

Voudris reported receiving consulting fees from 4C Medical, Abbott, and Medtronic, and speaking fees from Edwards Lifesciences. Rahman had no relevant financial relationships to report . 

Catherine Shaffer is a freelance science and medical writer with a background in molecular biology and pharmaceutical research. Her work has appeared extensively in scientific trade and mainstream publications and on public radio.