Amid Declining Use, Mechanical SAVR Valves Beat Bioprosthetic for Survival

LOS ANGELES, CA—In patients ages 60 years or younger undergoing surgical aortic valve replacement, mechanical valves are associated with a survival benefit compared with bioprosthetic valves, according to new registry data. But their use, based on an analysis of more than 100,000 patients, has been declining, investigators say.

“This data may inform heart teams in considering the optimal prosthesis used for aortic valve management in younger patients,” said Michael E. Bowdish, MD (Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA), who presented the late-breaking data here over the weekend at the 2025 Society of Thoracic Surgeons (STS) annual meeting.

Previous observational analyses have shown advantages with mechanical over tissue valves for middle-aged patients, but the lifelong requirement for anticoagulation as well as other issues have made these devices a harder sell. With several studies released last year indicating that TAVI is being offered increasingly to younger patients, the authors argue that the new data should be incorporated into appropriate decision-making, especially when considering lifetime management of aortic stenosis.

Despite calls for randomized trials in this space, Bowdish told TCTMD that is likely not going to happen. “This is the strongest data we’re ever going to get,” he said. “We can choose to accept that and use it to help inform our patients to make choices, or we can choose to not.”

He said the findings have already altered his practice. “It has changed how I view mechanical valves,” Bowdish said. “I think we owe it to our patients, too, when we have these discussions about aortic valve management, to offer and discuss strongly the option of a mechanical valve in people 60 and under.”

Discussing the findings during the session, Joseph A. Dearani, MD (Mayo Clinic, Rochester, MN), called the study a “wake-up call for every surgeon, every cardiologist, our industry partners, and our patients.” While the results confirm previous data from smaller institutional studies, the use of “sophisticated risk adjustment methods reinforces the reliability of the study’s conclusion,” he added.

Further, Dearani stressed the importance of the heart team in helping patients make balanced decisions that factor in both short- and long-term goals and needs. “This general shift towards bioprosthetic valves due to advancements in TAVR and SAVR technology calls for a critical reevaluation given the long-term outcomes presented in this study,” he said. “Much of this shift is due to unbridled enthusiasm in marketing by industry, with little based on evidence. It is also due in part to the cardiovascular community choosing to like what we like, and dismissing what we don’t like.”

Ultimately, “channeling younger patients down the tissue valve pathway is a flawed strategy for lifetime management of cardiovascular care and now goes against scientific validation,” Dearani said.

Speaking with TCTMD, incoming STS President Joseph F. Sabik III, MD (University Hospitals Cleveland Medical Center, OH), said the study is “really important, because it says: ‘Yes, you may be on Coumadin for a long time, but it’s very possible that you’ll live longer with this.’”

Registry Findings

For the study, simultaneously published in the Journal of the American College of Cardiology, Bowdish and colleagues included data from the STS Adult Cardiac Surgery Database on 109,842 patients ages 40 to 75 years who received isolated bioprosthetic (n = 94,125) or mechanical (n = 15,717) AVR at more than 1,000 centers between July 2008 and March 2019. The researchers linked the registry data with those from the National Death Index, and notably, excluded about 30% of patients due to insufficient information.

Overall, mechanical valve use decreased by about half over the study period, from almost 20% in 2008 to below 10% in 2019.

Compared with patients undergoing mechanical AVR, those receiving bioprosthetic valves tended to be older (65.2 vs 55.7 years), had a lower body mass index (31.0 vs 32.2 kg/m²), more often had hypertension (78.7% vs 71.8%) or prior PCI (6.7 vs 3.7%), and less often had severe aortic insufficiency (15.3% vs 23.6%).

Over a median follow-up of 5.4 years, the primary endpoint of all-cause mortality was lower with mechanical versus bioprosthetic AVR (log rank P < 0.0001). When patients were stratified by age, the hazard ratios for all-cause mortality were less than 1 with mechanical valves in those 60 and younger at the time of their operation, as compared with those treated with a bioprosthetic.

“There’s a clear advantage for mechanical aortic valves in patients less than 60 years old,” Bowdish said. “And there’s a suggestion of equipoise among those between 60 and 65.”

The findings held true after adjustment for age, with significant mortality benefits for mechanical valves seen in those ages 40-49 (adjusted HR 0.69; 95% CI 0.59-0.79) and 50-59 (adjusted HR 0.87; 95% CI 0.80-0.94) as well as in sensitivity analyses excluding those with pure aortic insufficiency, patients with a PROM > 4%, and those who received valves that have since been discontinued.

Survival vs Quality of Life

Not all surgeons are convinced by these data, some having long ago stopped implanting mechanical valves.

Anelechi Anyanwu, MD (Icahn School of Medicine at Mount Sinai, New York, NY), told TCTMD that surgeons are “polarized” on their opinions regarding the different surgical valve choices. “You get surgeons like myself who haven’t put a mechanical valve in in like 5 years, and . . . other surgeons will say 80% of my valves are mechanical,” he said. “The reality is while we like to say it’s [the] patient’s choice, it’s not. It’s often driven more by the institutional or surgeon practice.”

This is mostly because “we truly do not know which is better, a biological or mechanical. I think there’s no answer that fits all, because it depends on your perspective. If your perspective is purely survival, as in this study, then a mechanical valve probably will yield better survival than a biological valve.” If quality of life is the priority, then a tissue valve might make more sense, Anyanwu argued.

Despite large database studies already showing the advantages with mechanical valves, practice has not changed to favor them because “many patients simply do not want to take warfarin, even if the tradeoff is a slightly higher risk of mortality,” he continued, adding that this new study doesn’t provide evidence on the rates of valve-related complications or reoperation over time.

Regardless, Anyanwu said, “one thing that this study does show, I think, is that the results of surgery are excellent, whether you’ve got a mechanical or a biological valve.”

Speaking with TCTMD, Isaac George, MD (NewYork-Presbyterian/Columbia University Irving Medical Center, New York, NY), who was not involved in the study, agreed that it does not fully answer the question of which valve is better for most patients. There are residual confounders that cannot be mitigated fully, and the follow-up period is not long enough to account for reoperation rates, he pointed out.

“There’s no question, there’s data that your quality of life is less with a mechanical valve,” George said. “I’m not sure that we’re in a position to kind of force that decision on patients. We can tell them: ‘Look, you may have some end-of-life years that you gain with a mechanical valve.’ [But] I’m not entirely sure that you can say all that based on this data.”

He agreed that some surgeon preference might be at play, but “it also comes down to how the patient has been presented all of these options.”  Only a randomized trial will answer the question completely, “but I don’t think any patient is going to enter into that randomized trial,” George continued. “So I think we’re just going to end up looking at this kind of registry data, . . . and then patients will make their own decisions.”

What the study does highlight is “the need for other therapies,” he said. “We need better therapies. We need better biological tissue treatments that . . . make the tissue last longer probably. We need better anticoagulants. I think other surgeries should be really explored, especially for these younger patients below the age of 50.”

George pointed to a recent paper showing a reintervention rate of 8.3% with the Ross procedure over 25 years; the procedure has increased in prevalence in recent years, but still remains a complicated operation not available at all centers. “You’re going to see that these other therapies are probably going to become more important. Patients just don’t want mechanical valves.”

‘A More-Informed Story’

Part of the reason why mechanical valves have fallen out of favor is because “the data has never been totally clear,” said co-author Vinay Badhwar, MD (West Virginia University, Morgantown), during a deep dive session. “If you have data where there’s controversy, human behavior will pick what’s easy. And that probably is what has promulgated this trend, that’s largely experiential, to put in tissue valves in patients because we can.”

The new study represents “a more-informed story to tell those patients,” Badhwar added.

Patrick Myers, MD (Lausanne University Hospitals, Switzerland), who serves as the secretary general of European Association for Cardio-Thoracic Surgery, told TCTMD he could not recall the last time he implanted a mechanical valve, but the new data will now lead him to potentially push harder for them in some patients.

The increase in bioprosthetic valve use without “good-quality data” to support the practice means “we’ve definitely got indication creep,” he said.

J. Hunter Mehaffey, MD (West Virginia University), who also served as a study co-author, told TCTMD while the study findings “aligned well” with his current practice, he urged clinicians to make sure patients have “appropriate follow-up,” including access to a warfarin clinic. “It is incumbent upon us to do that,” he said.

One thing to note with anticoagulation is that many patients with aortic stenosis will develop a need for it over time for other indications like deep vein thrombosis or atrial fibrillation. “The decision between a mechanical and a bioprosthetic valve does not mean the choice of Coumadin or no Coumadin,” Mehaffey said.

To TCTMD, Badhwar said the new data has encouraged his team to use more mechanical valves and be more cognizant about patient selection. “The caveat is: we’re all big fans of TAVR and tissue valves, but for the right patient at the right time,” he said. “You have to be alive to have lifetime management strategies. And this is the whole point. Implanting a mechanical valve in a young patient is lifetime management.”