PARIS — Intermediate valve sizes are at least as safe and effective as the standard sizes now available for transcatheter aortic valve implantation (TAVI), according to an international randomized trial.
In a head-to-head comparison, the LANDMARK trial looked at valves from the new balloon-expandable Myval® by Merril Life Sciences and compared them with the balloon-expandable Sapien® from Edwards Lifesciences and the self-expanding Evolut® valve from Medtronic.
The new Myval platform offers multiple valves sized at 1.5 mm intervals, while the other two have valves that are generally sized at intervals of 3.0 mm.
at the Congress of the European Association of Percutaneous Coronary Interventions 2024.
The LANDMARK Trial
The trial enrolled 768 patients at 31 sites in 16 countries. They were randomized in a 1:1 fashion to the new platform or to one of the standards to compare the concept of intermediate valves with contemporary standards.
Seven sizes of Myval valves were used in the study, ranging from 20 mm to 29 mm at 1.5 mm increments. Two more sizes, 30.5 mm and 32.0 mm, were not included in this analysis but are being following in a registry.
The study also used Sapien valves sized 20 mm, 23 mm, 26 mm, and 29 mm and Evolut valves sized 26 mm, 29 mm, and 34 mm. There is also a 23 mm Evolut valve available, but it was not selected by any of the participating investigators.
Of the 336 patients given Myval valves, 48% were an intermediate size not available on one of the other platforms.
For the primary composite efficacy and safety endpoint of all-cause mortality, fatal or nonfatal strokes, VARC 3 or 4 bleeding, acute kidney injury, major vascular injury, moderate or greater valve regurgitation, or conduction disturbances requiring a new permanent pacemaker, the difference in absolute risk was slightly lower in the Myval arm, at 24.7% vs 27.0%, but not statistically significant. With that numerical difference favoring the Myval platform, noninferiority was demonstrated at 30 days with a high level of statistical significance, Dr. Serruys reported.
When each endpoint, with the composite primary endpoint, was evaluated separately in a secondary analysis, all-cause mortality and stroke incidence were identical in the two arms.
Major bleeding and acute kidney injury were nonsignificantly more common in the Myval group, while the incidence of moderate or greater valve regurgitation, placement of a new permanent pacemaker, and major vascular complications were nonsignificantly less common.
Precise Matching
The effective orifice area was consistently higher in the group receiving an intermediate valve relative to a Sapien valve. This was not significant for the 20 mm valve size, but it did reach statistical significance for the rest of the sizes. In contrast, there was no significant difference with the Evolut series.
The data suggest that intermediate sizes “enable precise and appropriate matching of devices to an individual anatomy,” at least relative to Sapien, said Dr. Serruys.
Martin Leon, MD, of Columbia University in New York, called LANDMARK an important step for considering how comparative trials should be conducted in the future.
However, he challenged the idea that this study compared devices for both safety and efficacy. Despite the evidence it provides on device and procedural safety over the short-term, he said few conclusions can be drawn about comparative efficacy after just 30 days. Rather, the true comparative value of the trial will be derived from “rigorous late follow-up,” he said.