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WASHINGTON -- A design change in the repositionable Lotus valve may have finally brought down the need for pacemaker placement, a small European study suggested.

After a tweak in the Lotus' anchoring mechanism -- the addition of Depth Guard, a design modification that minimizes the depth of the valve frame, effectively turning it from a funnel to a bell shape -- transcatheter aortic valve replacement (TAVR) with the device was associated with a 16% rate of permanent pacemaker implantation, according to the late-breaking RESPOND extension study presented at the Cardiovascular Research Technologies (CRT) annual meeting.

This means a halving of the permanent pacemaker placement rate found in the , which made these implants the Achilles' heel of the Lotus valve before Depth Guard (as pacemakers were placed in almost one-third of patients by 30 days).

Now operators are seeing "surgical-like results," said presenter , of Erasmus Medical Center in Rotterdam, the Netherlands.

But CRT session moderator , of MedStar Washington Hospital Center, still maintained that "the big elephant in the room is permanent pacemaker implantation." He also suggested that bias due to patient selection remains a possibility in the extension study, and that a small series of cases such as this merits a closer look.

"We will do some propensity-matching against the RESPOND trial," Van Mieghem responded. "But we don't know if that elephant is so big: EVOLUT had a 19% rate of permanent pacemaker implantation. [That rate] needs to go below 15%, and maybe reach surgical numbers which is 8%. But it will happen in the near future."

Compared with the RESPOND post-market study, the extension study showed numerically more mild paravalvular leak (14.7% versus 7.7%) and an elimination of moderate leaks (0% versus 0.3%).

Furthermore, two-thirds were discharged with no paravalvular leaks at all and none had severe leakage.

The RESPOND extension study was a 50-patient analysis wherein European participants got 23- and 25-mm Lotus valves for TAVR and started with an average Society of Thoracic Surgeons score 4.4%.

Devices were delivered largely via transfemoral access (96%) and a third of cases involved device repositioning, which was successful every time.

"Repositioning in a way is correcting a mistake," said , of Royal Brompton & Harefield NHS Foundation Trust in England, who suggested the adjustment would scratch off some aortic calcification and questioned if the high rate of repositioning indicated a problem with the valve. Di Mario was not involved in the study.

It remains unknown whether patients who had repositioned valves were more likely to get pacemakers, Van Mieghem acknowledged.

No patients died during Lotus implantation and 94% had mean aortic valve gradients successfully brought down below 20 mm Hg.

However, three patients had in-hospital strokes, two of which were disabling.

"This will not be the next-generation Lotus," the researcher emphasized. "The next-gen device will have a better profile and a more flexible delivery system on top of Depth Guard -- though we see that Depth Guard itself did lower the permanent pacemaker rate."

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