Do aortic annular size, valve type affect outcomes after TAVI?

Aortic annular size does not appear to have a major impact on valve haemodynamics, prosthesis-patient match (PPM), and mortality following transcatheter aortic valve implantation (TAVI), according to the results of a Singapore study.

In patients with small aortic annuli (SAA), haemodynamics at 1 year is better with self-expanding valve (SEV) than balloon-expandable valve (BEV), but PPM or mortality does not differ. No significant differences in mortality have been observed between aortic annular size, TAVI valve types, or PPM.

Researchers included 244 patients who underwent transfemoral TAVE for severe symptomatic native aortic stenosis at the National Heart Centre Singapore from July 2012 to December 2019. Outcomes measured were valve haemodynamics, PPM, structural valve degeneration (SVD), and mortality.

The mean Society of Thoracic Surgeons score was 6.22, with small aortic annulus (<23 mm) presenting in 52.5 percent of patients, medium aortic annulus (23‒26 mm) in 33.2 percent, and large aortic annulus (>26 mm) in 14.3 percent. More patients received SEV compared to BEV (65.2 percent vs 34.8 percent). [Ann Acad Med Singap 2022;51:605-618]

No significant differences were seen in index aortic valve area (iAVA), mean pressure gradient (MPG), PPM, SVD, or mortality across aortic annular sizes. In the SAA group, however, patients with SEV had larger iAVA (SEV vs BEV: 1.19 vs 0.88 cm/m2; p<0.01) and lower MPG (SEV vs BEV: 9.25 vs 14.17 mm Hg; p<0.01) at 1 year, with no differences in PPM or mortality.

Of note, aortic annular size, TAVI valve type, and PPM did not predict overall mortality up to 7 years. In addition, no significant difference in SVD was observed across aortic annular sizes up to 5 years.

“We observed several significant findings: annular size had no impact on valve haemodynamics, PPM, or mortality; in patients with small annular size, SEV had better valve haemodynamics than BEV but no differences in mortality; moderate or severe PPM did not impact on mortality, at least at 1 year; and annular size did not impact on longer-term SVD,” the researchers said.

Previous studies reported better valve haemodynamics and lower PPM rates with SEV than BEV, which might have been driven by the supra-annular location in SEV compared with the intra-annular location in BEV. [Circulation 2019;139:2685-2702; Circ Cardiovasc Interv 2017;10:e005013]

In terms of valve durability, annular size showed no impact on SVD. Although earlier studies had assessed the medium-to-long-term valve durability of TAVE, these were mostly done in Western cohorts of patients with predominantly larger annular areas. [EuroIntervention 2018:14:41-49; Eur Heart J 2017;38:2729-2738; J Am Coll Cardiol 2018;72:2687-2696; Lancet 2015;385:2485-2491]

“In summary, these studies have shown that valve haemodynamics remained consistent for up to 7 years, with similar freedom from severe SVD for TAVI when compared to surgical aortic valve replacement (SAVR),” the researchers said.

Data from patients with SAA proved significant, showing that severe PPM and small prosthesis size were found to result in accelerated bioprosthetic degeneration. [Interv Cardiol 2019;14:62-69]

“This study adds further knowledge in this burgeoning field, demonstrating the stability of valve haemodynamics especially in the SAA cohort up to 5 years,” the researchers said.

“We acknowledge that longer-term studies are warranted, especially among younger patients with smaller bioprostheses who are at risk of requiring future interventions through valve-in-valve TAVI or redoing SAVR in the longer term,” they added.