Q&A: Interventional cardiologist breaks down SMART data and TAVR valve performance in patients with small annuli
Some of the most talked about data at ACC.24 were the results of a late-breaking clinical trial comparing different transcatheter aortic valve replacement (TAVR) valves in patients with a small aortic annulus.
Eighty-seven percent of patients were women, a statistic practically unheard of in TAVR research.[1] Because women are typically underrepresented in modern TAVR trials, and they are up to 35% less likely to be treated for valve replacement than men, the trial’s authors hoped they could bring about significant change by including as many women as possible in their research.[2]
The SMART (SMall Annuli Randomized To EvolutTM or SAPIENTM*) trial included one-year data from 737 patients randomized to receive either a self-expanding Evolut TAVR valve from Medtronic or a balloon-expandable SAPIEN 3 valve from Edwards Lifesciences. Evolut models implanted for the study included the PRO, PRO+ and FX. SAPIEN models included the 3 and 3 Ultra. All patients presented with symptomatic severe aortic stenosis (SSAS) and a small aortic annulus. †
Overall, self-expanding Evolut valves were linked to comparable clinical outcomes and superior valve performance after one year.
Bioprosthetic valve dysfunction was seen in 8.4% of women with a self-expanding TAVR valve and 41.8% of women with a balloon-expandable valve. The aortic valve mean gradient was 7.7 mm Hg with the self-expanding valve and 15.8 mm Hg with the balloon-expandable valve.[3]
Moderate or severe prosthesis-patient mismatch (PPM), meanwhile, was seen in 9.2% of women with the self-expanding valve and 34.1% of women with the balloon-expandable valve at 30 days.
Suzanne Baron, MD, MSC, director of interventional cardiology research at Massachusetts General Hospital and director of outcomes research at the BAIM Institute for Clinical Research, was a panelist at ACC.24 when the SMART results were presented. She spoke to Cardiovascular Business about the trial, highlighting the biggest takeaways for both interventional and general cardiologists.
Read the full conversation below:
Cardiovascular Business: Can you provide a little background about what it’s like treating patients with a smaller aortic annulus? Does it present specific challenges you don’t see with other patients?
Understanding the optimal valve implementation choice and technique is important for any TAVR patient, but especially those with small annuli. For example, some patients with smaller aortic annuli, depending on their body habitus, may face a higher risk for PPM. There have been studies in both the surgical [4, 5, 6] and TAVR literature that suggest PPM may be associated with worse clinical outcomes.[7]
Additionally, since we are treating younger and younger patients with AS, we also have to consider the lifetime management of these patients—specifically, what are their options going to be for a second valve if they outlive the first one? Patients with small valves or small annuli may have more limited percutaneous options for a second valve, so you have to think about that when making a plan for their first valve.
What were your initial thoughts about the SMART trial results?
Like I said at ACC.24, this is the largest randomized controlled trial that we have comparing the two most commonly used transcatheter valve implants in the current era. I felt really reassured to see that both platforms can deliver a safe, effective treatment option for patients with severe AS in terms of death, stroke and heart failure rehospitalization out to 12 months.
"The number of women in this trial was incredible. Women are historically underrepresented in cardiovascular trials, particularly device trials, and SMART was 87% women."
Suzanne Baron, MD, MSC, Director of Interventional Cardiology Research, Massachusetts General Hospital in Boston
Another thing that really stood out was how far TAVR technology and our procedural techniques have come over the years. The adjudicated adverse event rates were pretty low despite this being an elderly population with many comorbidities. When you look back at the complication rates in the early pivotal TAVR trials, it really highlights just how much this field has advanced over the last decade.
Lastly, the number of women in this trial was incredible. Women are historically underrepresented in cardiovascular trials, particularly device trials, and SMART was 87% women. With this multicenter dataset of over 700 women who were treated with TAVR in the current era, we will have the opportunity to explore and examine a lot of different aspects of TAVR in women and this will certainly help move our field forward.
As an interventional cardiologist, what is your perspective on the differences in valve dysfunction and aortic valve mean gradient between the two types of TAVR valves?
I was not surprised that the hemodynamic data was in favor of the self-expanding Evolut valve –this was expected given the supra-annular nature of the valve platform. The key will be whether the hemodynamic data ends up impacting long-term clinical outcomes. We didn’t see a difference in clinical outcomes between the two TAVR platforms after one year, but it’s still early. There is emerging data that suggest higher gradients and severe prosthesis-patient mismatch can lead to earlier valve deterioration, which could then lead to worse clinical outcomes like higher rates of heart failure hospitalizations or valve reinterventions. Whether this will be borne out in the five-year follow up of the SMART trial is unknown, but if the five-year data shows that valve dysfunction and these other hemodynamic findings are associated with significant differences in death, heart failure and stroke, then that could be a real game-changer.
Will these results impact treatment implant decisions you make on a day-to-day basis?
Of course! Valve hemodynamics will continue to be a factor that I take into consideration when I am with an AS patient with a smaller annulus. But I think it is important to note that it is one of many anatomical factors to consider, including effacement of sinuses, coronary height, calcification in the LVOT, aortic root angle and the expectation of a second implant, and that just generally speaks to the complexities of decision-making in treating this patient population. And really, this is where a well-oiled heart team really can shine in making sure that every aspect of the patient’s clinical and anatomical presentation is being considered.
What should general cardiologists take away from the SMART trial results?
My big takeaway for general cardiologists is—look at these great TAVR outcomes! We have a tried and true treatment for managing patients, men and women, with SSAS that has really matured and is performing very well!
Nevertheless, there is still an undertreatment of SSAS in our patient population—studies have found that up to 50% of patients with SSAS are not referred for to a heart team or for valve treatment. Women are even less likely to be referred. So I really want to encourage general cardiology to refer your patients with AS to a valve center for evaluation, even if you think it may be early for treatment because the AS is only moderate or the patient doesn’t have many symptoms. If seeing patients earlier will help address the undertreatment of SSAS, then it is worth it to me.
Click here for indications, safety and warnings. Like any other procedure, TAVR risks can include death, stroke, bleeding.
™* Third-party brands are trademarks of their respective owners. All other brands are trademarks of a Medtronic company.
† In patients with small annuli (area ≤ 430 mm2) in all-comers trial, consisting of majority low surgical risk participants (52.1%).
Additional data about treating aortic stenosis in women is available here.
References:
Rice CT, Barnett S, O'Connell SP, et al. Impact of gender, ethnicity and social deprivation on access to surgical or transcatheter aortic valve replacement in aortic stenosis: a retrospective database study in England. Open Heart. September 2023;10(2):e002373.
Mehran R, et al. Small aortic annuli patients treated with TAVI: Outcomes in women in the SMART trial. Presented at EuroPCR; May 2024
Pibarot P, Dumesnil JG. Hemodynamic and clinical impact of prosthesis-patient mismatch in the aortic valve position and its prevention. J Am Coll Cardiol. 2000;36:1131-41
Head SJ, Mokhles MM, Osnabrugge RL, et al. The impact of prosthesis-patient mismatch on long-term survival after aortic valve replacement: a systematic review and meta-analysis of 34 observational studies comprising 27 186 patients with 133 141 patient-years. Eur Heart J. Jun 2012;33(12):1518-29.
Mihaljevic T, Nowicki ER, Rajeswaran J, et al. Survival after valve replacement for aortic stenosis: implications for decision making. J Thorac Cardiovasc Surg. Jun 2008;135(6):1270-8; discussion 1278-9. doi:10.1016/j.jtcvs.2007
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. Dec 4 2018;72(22):2701-2711.
Michael has more than 18 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.