BEVs Versus SEVs in Women With Small Annuli

Corresponding Author

The transcatheter aortic valve replacement (TAVR) era has advanced rapidly, yet the small aortic annulus (SAA), variably defined as <430 mm², remains a persistent challenge. SAA is disproportionately common in women and continues to raise concerns about prosthesis–patient mismatch (PPM), elevated transvalvular gradients, and adverse long-term outcomes. Recent randomized data, including the SMall Annuli Randomized To Evolut trial and its women-specific subgroup, demonstrate that self-expanding valves (SEVs) achieve superior hemodynamic performance compared with balloon-expandable valves (BEVs) while remaining noninferior for the composite clinical endpoint of death, disabling stroke, or heart failure hospitalization at 12 months.^1,2 A contemporary meta-analysis corroborated these hemodynamic advantages of SEVs, with no meaningful differences in early stroke, survival, or heart failure rehospitalization.³ These studies appropriately called for longer-term data, particularly in women with SAA.

Until now, dedicated follow-up in patients with SAA has been limited to 5 years. The current study published in JACC: Asia fills this critical gap by providing 7-year outcomes exclusively in women from the prospective, multicenter OCEAN-TAVI registry.⁴ The investigators identified 1,827 women treated with BEVs and 805 with SEVs between 2013 and 2019; after 1:1 propensity score matching (PSM), 744 pairs were analyzed. Strikingly, 88% of the cohort met SAA criteria. Echocardiographic follow-up confirmed that BEVs yielded persistently smaller effective orifice areas and higher mean pressure gradients through 7 years, accompanied by higher PPM rates. Yet in the PSM cohort, BEVs were associated with lower all-cause mortality and stroke incidence, whereas heart failure rehospitalization rates were similar. Multivariable models found no independent association between valve type and any primary endpoint; independent predictors included age, Clinical Frailty Scale score ≥4, atrial fibrillation, NYHA functional class III/IV, peripheral artery disease, low hemoglobin, severe PPM, and ≥mild paravalvular leak.

This 7-year women-specific data set represents a major strength, offering the longest follow-up to date in the study group at the highest risk for PPM-related concerns. However, it is crucial to acknowledge several limitations that necessitate careful interpretation of its findings. The study is observational, and even rigorous propensity matching remained incomplete: Absolute standardized differences for the Society of Thoracic Surgeons score and transfemoral approach exceeded 0.10, and left ventricular ejection fraction differed significantly between groups (P = 0.036). Furthermore, the SEV group presented with a higher proportion of high-risk characteristics, suggesting that residual imbalance may have skewed adverse outcomes. The advanced age of the cohort (mean ≈85 years) likewise contributed to diminished follow-up rates at 7 years, resulting in small and imbalanced event numbers at later time points, which questions the robustness of the conclusions drawn from highly unequal at-risk study group. Lastly, the use of earlier device generations and a potentially misaligned SAA definition, largely based on Western cutoffs, might not fully reflect contemporary advancements or Asian anatomical specifics.

Despite the high prevalence of SAA in the current report, the incidence of severe PPM remained strikingly low (≈2% overall) compared with rates of 20% to 25% in Western cohorts.⁵ This striking difference prompts a critical question: Should the very concept of “SAA” be redefined with study group–specific cutoffs, especially given the smaller body surface area typical of East Asian women? Moving forward, prospective cohort studies are urgently needed in Asian study groups to re-evaluate and, if necessary, redefine SAA criteria tailored to local body size and clinical outcomes. Establishing a validated, study group–specific definition is essential before rigorously reassessing the comparative performance of SEVs versus BEVs, with adequately powered randomized controlled trials serving as the ultimate step for comparing contemporary platforms in women with SAA.

These findings also bring to the forefront a key question within the field: Why do SEVs consistently deliver superior hemodynamics yet fail to translate into improved survival or fewer heart failure rehospitalizations? In the PSM analysis, BEVs paradoxically showed lower all-cause mortality and stroke—a signal also observed, albeit subtly, in earlier registries. Several explanations merit consideration. First, residual confounding may persist despite matching; SEV-treated patients retained modestly higher Society of Thoracic Surgeons scores and more complex anatomy, including challenging vascular access and heavier annular calcification. Second, SEVs were associated with higher rates of early periprocedural complications, including permanent pacemaker implantation and disabling stroke. Third—and perhaps most compelling—is the over-riding influence of non-valve-related factors, such as advanced frailty, atrial fibrillation, and anemia, in this Japanese cohort of older patients. The multivariable analysis supports the latter: Once clinical covariates were accounted for, valve type lost independent prognostic significance. This pattern aligns closely with prior 5-year data in which SEV’s hemodynamic advantages similarly failed to confer a survival benefit,^6,7 as well as 5-year Placement of AoRTic TraNscathetER Valves trial findings showing no correlation between PPM severity and hard clinical outcomes with contemporary sizing.⁸

A final layer of nuance emerges when considering bicuspid aortic valve morphology in this study group of predominantly female patients with SAA. Our team’s recent observational study demonstrated comparable clinical outcomes and hemodynamic profiles between bicuspid and tricuspid aortic stenoses in patients with SAA undergoing TAVR.⁹ Whether annular size or leaflet morphology per se is the dominant anatomic determinant will require confirmation in large-scale randomized controlled trials.

In summary, Iwata et al⁴ have delivered a landmark contribution. By focusing exclusively on women with SAA, they provide the longest follow-up to date and demonstrate that both BEVs and SEVs can achieve acceptable long-term outcomes when selected thoughtfully. Rather than declaring a universal winner, the data support a patient-specific approach: SEVs may be preferred when minimizing PPM is critical, whereas BEVs may be better for patients at higher risk of pacemaker implantation or stroke. Importantly, the hemodynamic advantage of SEVs does not automatically translate into improved survival, and classical risk factors drive prognosis more powerfully than valve design. Given the strikingly low PPM rates observed despite the high prevalence of SAA by current criteria, the definition of SAA itself may need to be redefined in a study group– and body size–specific manner. These insights should guide heart team decision-making and inform future device trials as TAVR expands into lower-risk and younger study groups.

Funding Support and Author Disclosures

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.