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MIAMI -- Early data from next-generation transcatheter aortic valve implantation (TAVI) devices are promising, but not without safety concerns, researchers reported here at the opening day of the Transcatheter Cardiovascular Therapeutics meeting.

The repositionable Direct Flow valve had a 3% rate of 30-day all-cause mortality in the DISCOVER trial, with a single death due to pneumonia complications among the initial 33 patients reported on by Joachim Schofer, MD, of Hamburg University Cardiovascular Center in Hamburg, Germany, and colleagues.

By contrast, no deaths have been seen with the retractable Portico valve in the first-in-man experience of 21 patients with at least 30 days of follow-up, presented by Ganesh Manoharan, MBBCh, MD, of the Royal Victoria Hospital in Belfast, Northern Ireland.

Aortic regurgitation was mild at worst for nearly all patients treated in the both studies and investigators from each study chalked that result up to ability to reposition the valves after checking hemodynamics.

"I don't see a niche, I see an alternative for the valves which are presently on the market," Schofer told attendees. "I think if you can really almost eliminate aortic regurgitation it's worth thinking about in terms of what we have in our hands so far."

Aortic regurgitation is common with the Sapien TAVI device, which is the only percutaneous valve approved by the FDA.

"The Direct Flow valve can be safely and effectively used to treat high and extreme surgical risk patients with aortic stenosis," Schofer concluded at the session, echoing the words of Manoharan about the early data with the Portico valve.

The Portico valve study included 21 patients with data available, five followed out to 1 year, at two centers in Canada and one in Belfast.

They received the 23 mm self-expanding bovine and porcine valve and transfemoral delivery system. The device can be fully resheathed, which six of the patients had done during their procedure to reposition it, and retrievable.

There were no deaths, strokes, heart attacks, or cases that needed a pacemaker implanted.

While there was one vascular complication within 30 days of implantation, the main issue was bundle branch block, which occurred in six patients.

Serious adverse events included GI distress, shortness of breath, hypothyroidism, fatigue, atrial fibrillation, and cerebrovascular ischemia in one case, but none were deemed related to the device or procedure.

Peak gradients improved substantially and no patients had more than mild aortic regurgitation.

New York Heart Association functional class improved from mostly class III at baseline to all class I in the Belfast group by 30 days and to mostly class I and II in the Canadian group.

"These are encouraging results," Manoharan told attendees, though noting that it reflected the experienced centers doing the procedures and the guidelines used to manage them, including having heparin on board at incision and dual antiplatelet therapy afterward.

Also, due to anatomical considerations, all the patients were women.

Like the Portico device, the Direct Flow valve was repositionable and fully retrievable, but with a design much more like surgical valves.

The DISCOVER trial was designed for submission to European regulators and is planned to eventually include 100 patients.

Of the 33 that have 30-day follow-up so far, all were successful, though three had to have the device retrieved to place a different size.

The average time for valve positioning and hemodynamic assessment was 18 minutes.

For the primary trial endpoint, 97% of the patients remained alive at 30 days. None died from cardiovascular causes.

The combined procedural success rate by Valve Academic Research Consortium (VARC) criteria was 97% due to one patient having a median gradient a little over 20 mm Hg.

The other component aspects were seen in all cases, with a single valve implanted in the proper location with proper positioning and successful vascular access, delivery, and retrieval of the delivery system.

For the primary safety endpoint, the combined VARC safety endpoint occurred in two patients with three events total for a rate of 9%, which included the one pneumonia-related death and two major strokes.

One patient also had a periprocedural heart attack, but the most events centered on new pacemaker implantation (six cases).

Schofer cautioned about the small numbers in the trial and noted that the rate of new pacing appeared to decline as the trial has accrued further patients.

The valve worked as expected, with mean gradients falling from 46 mm Hg at baseline to 13 mm Hg at 30 days.

Three-quarters of the patients had at least a one functional class improvement, with most patients ending up in class I.

The same proportion had no or only trace aortic regurgitation, and only one -- "with very bulky calcification" of the native valve -- had moderate regurgitation, which Schofer called a virtual elimination.