Self-expanding valves show good haemodynamic performance in small annuli

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Damiano Regazzoli

A retrospective registry comparing four self-expanding transcatheter heart valves has demonstrated good haemodynamic performance in small aortic annuli, with low post-procedure gradients, large orifice areas, and a low incidence of severe patient–prosthetic mismatch (PPM).

Writing in JACC: Cardiovascular Interventions, investigators Damiano Regazzoli (Humanitas Research Hospital, Rozzano-Milan, Italy) et al report that the supra-annular designs (EvolutR, EvolutPro, both Medtronic, and AcurateNeo, Boston Scientific) seemed to slightly outperform the intra-annular design (Portico, Abbott). Similar rates of severe paravalvular leak (PVL) and need for pacemaker implantation were reported in the real-world cohort of aortic stenosis patients, while more-than-mild PVL seemed to be slightly more frequent with Portico.

TAVI-SMALL is a retrospective registry of patients with severe aortic stenosis and a small annulus. The study sought to evaluate and compare the outcomes of transcatheter self-expandable prostheses in these patients. The authors explain: “We decided to focus our attention on this specific subgroup considering that patients with small aortic annuli showed the highest benefit in terms of valve forward haemodynamic and PPM in those studies comparing the outcome after TAVI [transcatheter aortic valve implantation] and SAVR, [surgical aortic valve replacement] especially in case of SEVs implantation. The clinical impact of PPM in patients treated percutaneously is still not clear and demands further investigations, but TAVI-SMALL registry represents a starting point to shed light on this topic.”

Of the 859 participants, 397 were treated with Evolut R, 84 received EvolutPro, 201 Acurate (both Neo and TA), and 177 Portico. Primary endpoints were post-procedure mean aortic gradient, indexed effective orifice area (iEOA), and rate of severe PPM.

The researchers found that pre-discharge gradients were consistently low in every group, with a slight benefit with EvolutR (8.1 mmHg, 95% confidence interval [CI] 7.7–8.5) and EvolutPro (6.9 mmHg, 95% CI 6.3–7.6) compared to Acurate (9.6 mmHg, 95% CI 8.9–10.2) and Portico (8.9 mmHg, 95% CI 8.2–9.6) groups (p<0.001). Mean iEOA was 1.04 cm2 /m2 (95% CI 1.01–1.08) with a trend for lower values with Portico. Interestingly, considering only Acurate Neo (supra-annular valve implanted transfemorally), there were no differences in term of gradients and PPM as compared with EvolutR and EvolutPro. No significant differences were reported in terms of severe PPM (overall rate: 9.4%, p=0.134), permanent PM implantation (15.6%), and peri-procedural and one-year adverse events.

Regazzoli and colleagues write: “Currently available SEVs showed excellent acute and midterm clinical results, with a low incidence of adverse events. The use of SEVs proved to be effective and showed good haemodynamic results in patients with small (<23 mm of derived diameter) and very-small (<20 mm) annuli. An inverse correlation between annular perimeter and postprocedure gradients was found, but its clinical relevance is not clear, since the incidence of severe PPM was low in patients with both small (9.4%) and very small annuli (13.7%).”

They add: “These data, comparable to those observed in other contemporary TAVI studies, are consistent between groups, suggesting good procedural planning and implantation technique, irrespective of the selected device.”

The non-randomised and retrospective design of the study could have led to some selection bias, the authors concede, although, they say, “we did not observe significant baseline differences between SEV groups”. Nevertheless, Regazzoli et al say, the study “represents an important piece of evidence by confirming favourable outcomes of these devices in this setting”.

An accompanying editorial by Michele Pighi, and Flavio Ribichini, (University of Verona, Verona, Italy) described the findings as “interesting”. They say: “In light of the recent extension of TAVI indication to low-risk patients, the TAVI-SMALL study provides a strong stimulus for the development of future studies investigating the long-term performance of transcatheter valves, striving for individualisation of the treatment strategies in this particularly challenging anatomical setting.”

And, in a second paper also published in JACC: Cardiovascular Interventions, authors Aditya Sengupta (Mount Sinai Medical Center, New York, USA), Syed Zaid (Westchester Medical Center, New York, USA) et al, outlined one-year results of TAVI with the Sapien 3 (Edwards) valve in extremely large annuli. They found overall mortality and stroke rates were 18.2% and 2.4%, respectively, at one year, and a quality-of-life index improvement from baseline to 30 days and at one year (both p<0.001). Mild paravalvular aortic regurgitation (AR) occurred in 21.7%, while moderate or greater paravalvular AR occurred in 4.3%. Mild and moderate/severe transvalvular AR occurred in 11.6% and 0%, respectively. Valve gradients remained stable at one year.

The authors say that they have demonstrated the “continued utility of Sapien 3 TAVI in annuli >683mm2 with satisfactory midterm clinical and echocardiographic outcomes”, and call for longer follow-up to evaluate the durability of the 29 mm Sapien 3 valve in patients with extremely large annuli.

David A Wood and Janarthanan Sathananthan (St Paul’s and Vancouver General Hospitals, and University of British Columbia, Vancouver, Canada) comment in the same issue: “Segupta et al should be congratulated on reporting this series in annular areas >683 mm2 with acceptable outcomes; however, future THVs should be designed to function optimally at a wide range of conditions to accommodate variability in patient anatomy and comorbidities.”


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