Prosthesis-patient mismatch after TAVR: Key details cardiologists need to know

“All cardiologists should be aware of PPM,” explains Herrmann, the John W. Bryfogle Professor of Cardiovascular Medicine and Surgery with the University of Pennsylvania’s Perelman School of Medicine. “They should be talking to their TAVR operators about it when they refer patients, in order to avoid later problems. Cardiologists should be able to recognize when patients may benefit from one type of valve over the other.” 

Herrmann has emerged as a leading voice on the long-term impact of PPM after TAVR. In 2018, for instance, he led a study of PPM rates focusing on data from the Society of Thoracic Surgeons (STS) /American College of Cardiology (ACC) Transcatheter Valve Therapy (TVT) Registry.³ And in 2024, he led the SMART Trial, an in-depth analysis of TAVR patients who presented with severe aortic stenosis and a small aortic annulus.⁶

“There was a lot of controversy at first, because it was unclear if PPM mattered as much after TAVR as it does after surgery,” Herrmann says. “Changes in the definition for PPM, timing of measurement and follow-up affect both the reported incidence and its impact on patients. Now that we keep learning more and more, I would say it is clear that it does matter when it occurs.”

How common is prosthesis-patient mismatch after TAVR?

Care teams look for PPM by dividing a patient’s effective orifice area (EOA) by their body surface area. An indexed EOA less than 0.85 cm² / m² can be a sign of trouble.³

When Herrmann’s team explored data from the STS/ACC TVT Registry, they identified moderate and severe PPM in 25% and 12% of TAVR patients, respectively, and found that women and a smaller valve size were risk factors.³ A more recent single-center analysis focused exclusively on young and low-risk patients found that moderate or severe PPM after TAVR with a modern balloon-expandable valve occurred in 39% and 7.4% (P < 0.0001) of patients, respectively.⁷

The Herrmann-led randomized SMART Trial, meanwhile, compared PPM rates in patients receiving a self-expanding valve vs. those receiving a balloon-expandable valve in patients with a small aortic annulus, 87% of whom were women. Moderate or severe PPM after 30 days was found in 11.2% of patients in the self-expanding valve group and 35.3% of patients in the balloon-expandable group (P < 0.001). Severe PPM after 30 days occurred in 1.8% of patients in the self-expanding group and 7.1% of patients in the balloon-expandable group.⁶

What’s most notable for patients and general cardiologists is the potential post-TAVR impacts of PPM, which include mortality, heart failure hospitalization, lower quality of life (QOL) and future valve reinterventions.^3,4,7 PPM is most commonly found in younger patients, women and patients with a small aortic annulus or a larger body surface area.³ While some cardiologists tend to only worry about PPM in female patients—it can be equally harmful for both sexes.

“Men can have a small annulus too,” Herrmann says. “Especially in Asian populations, where people are generally smaller. This is not an issue that only impacts our female patients.”

He also highlights the established connection between obesity and PPM. If a patient—male or female—has a small cardiac anatomy, but is considerably obese or has a larger BSA, this should be considered at the time of the procedure, because it can significantly impact their long-term risks.

“You can be a big person with a small annulus,” he says. “In fact, those patients face the greatest risk of severe PPM, because they have that larger body surface area.” 

Tracking patient outcomes after prothesis-patient mismatch

One thing the structural heart community agrees with is the fact that PPM after TAVR is associated with worse patient outcomes. Compare data on TAVR patients with and without PPM and you’ll find PPM patients face higher long-term risks of all-cause mortality^3,4,7 and heart failure hospitalization after TAVR.^3,4,7 In addition, Herrmann adds, PPM after AVR has been linked to less left ventricular mass regression, an impaired normalization of coronary flow reserve, an impaired exercise tolerance and fewer improvements in QOL.^3,7,8,9

Importantly, Herrmann notes, it takes time for PPM to affect clinical outcomes. When looking at mortality curves for patients with PPM and without PPM, it may take several years for curves to diverge from one another.³

“In my experience, this makes it much harder to isolate the effect of PPM until at least three years after treatment,” he says. “That’s why we focus so much on data from low-risk patients; they tend to live much longer, allowing us to see the effects of adverse hemodynamics firsthand. You can study PPM in an 86-year-old high-risk patient, but you learn much more if you study PPM in younger patients with longer life expectancies and fewer competing risks for an adverse outcome.” 

Even the short-term data make it clear that PPM is associated with certain risks that will follow a patient for the rest of their life. Prothesis-patient mismatch can start to elevate a patient’s risk of mortality within 3 years of valve replacement.^3,4,7  In addition, the increased risk of heart failure hospitalization and lower QOL can heavily influence the lifetime management of a TAVR patient.¹⁰

Supra-annular, self-expanding TAVR valves reduce the risk of prosthesis-patient mismatch

The SMART Trial is providing fresh insights into how different valve types may influence the risk of PPM after TAVR patients with a small annulus^¶. Herrmann and his team enrolled 737 patients with small annuli, randomizing each one to receive either a supra-annular, self-expanding Evolut^TM valve from Medtronic or an intra-annular, balloon-expandable SAPIEN^TM* valve from Edwards Lifesciences.⁶

The two valve types had comparable safety and clinical outcomes at 2 years, but supra-annular, self-expanding valves were associated with multiple sustained benefits from a hemodynamic perspective. Perhaps the biggest of those benefits was the fact that moderate or severe PPM occurred in 10.3% of patients with a supra-annular, self-expanding valve and 35.1% of patients with an intra-annular, balloon-expandable valve.

“We’ve seen that PPM is more common with balloon-expandable valves in patients with small annuli,”⁶ Herrmann explains. “With the SMART data, the big question is how PPM will impact those five-year patient outcomes. We’re about to hit three years for those patients, so we will just have to wait a bit longer to find out.”

While Herrmann has discussed the SMART data at industry conferences all over the world, one point that gets brought up a lot is the idea that measuring gradient may be different with different prostheses. 

“There is a thought that we may be overestimating the incidence of severe PPM with balloon-expandable valves, because you have a little more turbulence at the entry point,” he says. “There is some in vitro data that supports that being the case, but I don’t think turbulence is a good thing either.”¹¹ 

PPM is preventable— and it all starts with proper planning

Herrmann notes that clinicians are learning more about PPM with each passing year. SMART data will follow patients for five years and other long-term TAVR trials focused on low-risk patients will provide valuable insights into the clinical impact of PPM following TAVR with a variety of valve types. 

Even now, care teams have plenty of data that can help them minimize the risk of PPM. If a patient with a small aortic annulus presents for TAVR, for instance, it may be prudent to consider implanting a supra-annular, self-expanding TAVR valve. There also may be cases where surgery with aortic root enlargement should be considered, Herrmann says. The last few years of clinical research have helped pave the way for these discussions. 

Of course, collaboration is woven into the very DNA of TAVR. From its earliest days, TAVR set a new standard for multidisciplinary care, bringing together interventional cardiologists, cardiac surgeons, imaging specialists, and referring physicians in a unified heart team approach. This model not only elevated procedural planning and patient selection—it redefined how cardiovascular care is delivered.

If this collaborative momentum continues, TAVR outcomes—for patients with and without prothesis-patient mismatch—will only improve, driven by smarter referrals, better coordination, and a deeper understanding of disease progression.

† Dr. Herrmann did not receive compensation for this piece. However, he has received compensation from Medtronic Medical Education and Proctor Programs.

¶ In patients with small annuli (area ≤ 430 mm²) in all-comers trial, consisting of majority low surgical risk participants (52.1%)

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References:

1. Rahimtoola SH. The problem of valve prosthesis-patient mismatch. Circulation. 1978;58:20-24.
2. Hahn H, Pibarot P. Prosthesis-patient mismatch in transcatheter and surgical aortic valve replacement. Ann Cardiothorac Surg. 2024;13(3):211-223.
3. Herrmann HC, Daneshvar SA, Fonarow GC, et al. Prosthesis–patient mismatch in patients undergoing transcatheter aortic valve replacement: From the STS/ACC TVT Registry. J Am Coll Cardiol. 2018;72(22):2701-2711.
4. Sá MP, Jacquemyn X, Van den Eynde J, et al. Impact of prosthesis-patient mismatch after transcatheter aortic valve replacement. JACC Cardiovasc Imaging. 2023;16(3):298-310.
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8. Bakhtiary F, Ahmad AE, Autschbach R, et al. Impact of pre-existing comorbidities on outcomes of patients undergoing surgical aortic valve replacement: rationale and design of the international IMPACT registry. J Cardiothorac Surg. 2021;16(1):51.
9. Pibarot, P, Weissman, N, Stewart, W. et al. Incidence and Sequelae of Prosthesis-Patient Mismatch in Transcatheter Versus Surgical Valve Replacement in High-Risk Patients With Severe Aortic Stenosis: A PARTNER Trial Cohort-A Analysis. JACC. 2014 Sep, 64 (13) 1323–1334.
10. Pibarot P. Prosthesis-patient mismatch after transcatheter aortic valve replacement. J Am Coll Cardiol. 2018;72(22).
11. Shames S, Koczo A, Hahn R, et al. Flow characteristics of the SAPIEN aortic valve: the importance of recognizing in-stent flow acceleration for the echocardiographic assessment of valve function. J Am Soc Echocardiogr. 2012;25(6):603-609.

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