SMART Trial: What is the Best Valve for Small Annuli?

Transcatheter aortic valve intervention (TAVI) has been shown beneficial over the years. However, a significant subgroup of patients with small aortic annulus, which make approximately one third of cases and have a higher incidence in women, face additional challenge, such as higher incidence of mismatch, reduced exercise capacity and shorter durability. 

Anillos aórticos pequeños, ¿Qué válvula deberíamos elegir?

Self-expanding and balloon expandable valves (SEV and BEV) represent different scaffolds and have shown variations in hemodynamic performance. 

In patients with small annuli, these differences can be significant, even though so far it remains unclear what scaffold offers the best benefit. 

This was a 12-month analysis of the SMART trial (Small Annuli Randomized to Evolut or SAPIEN); an international prospective randomized 1:1 study including 715 patients with severe aortic stenosis. Of these, 355 received SEV and the rest BEV.

The valves used were Evolut PRO/PRO+/FX (Medtronic) and SAPIENS 3 and Ultra (Edwards Lifesciences).

Primary outcomes were assessed at 12 months: the clinical end point was a combination of death, disabling stroke, rehospitalization for cardiac failure, and the bioprosthesis dysfunction end point included hemodynamic structural dysfunction (mean gradient ≥20 mmHg), non-structural valve dysfunction (mismatch or aortic regurgitation at least moderate), valve thrombosis, endocarditis or reintervention.

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There were no differences between the populations. Mean age was 80, 86% were women, mortality STS was 3.3%, most were hypertensive, 32% was diabetic, 18% had COPD, 12% had suffered stroke, 4% had chronic kidney disease, 20% atrial fibrillation, 7% acute myocardial infarction and ejection fraction was 61%.

The presence of complete right bundle branch block was 6% and atrial fibrillation was 19%.

SEV valves were mostly 26 mm (68%) and fewer were 29 mm, while the most used BEV was 23 mm (90%) and the rest were 20 mm.

After a year, clinical primary end point resulted  9.4% among SEV patients vs. 10.6% for BEV patients (difference, −1.2 percentage points; CI 90%, −4.9 to 2.5; P<0.001 for non-inferiority; hazard ratio, 0.90; CI 95%, 0.56 to 1.43), but the bioprosthesis dysfunction end point favored SEV (9.4% for SEV vs 41.6% for BEV; a difference of −32.2 percentage points; CI 95%, −38.7 to −25.6; P<0.001).

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As regards the clinical end point, analyzed separately, there were no differences in mortality, stroke or rehospitalization for cardiac failure, but there was in valve dysfunction end point, seeing as SEV presented hemodynamic structural dysfunction (3.2% vs 32.2%, a −29.1 difference in percentage points; CI 95%, −34.6 to −23.5), and nonstructural dysfunction (5.9% vs 18.2%; a −12.3 difference in percentage points; CI 95%, −17.6 to −7.0), with no difference in endocarditis, valve thrombosis or reintervention. 

The echocardiographic analysis showed valve area was larger among SEV patients (1.99 cm2 vs 1.5 cm2, p<0.0001), and mean gradient higher (7.7 mmHg vs 15 mmHg, p<0.0001).


Among patients with severe aortic stenosis and small annulus undergoing TAVR, supra-annular self-expanding valves were not inferior vs balloon expandable valves as regards clinical evolution, but resulted superior as regards bioprosthetic valve dysfunction, at 12 months. 

Dr. Carlos Fava - Consejo Editorial SOLACI

Dr. Carlos Fava.
Member of the Editorial Board of

Original Title: Self-Expanding or Balloon-Expandable TAVR in Patients with a Small Aortic Annulus.

Reference: H.C. Herrmann, et al. NEJM DOI: 10.1056/NEJMoa2312573.

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