DISCOVER Registry: Positive Results Seen for Next-Generation TAVR Device at 1 Year
New 1-year data from the DISCOVER registry indicate that the Direct Flow Medical valve performs well in extreme-risk patients with severe aortic stenosis undergoing transcatheter aortic valve replacement (TAVR). The findings, from an oral abstract, are being presented Thursday at TCT.
Federico De Marco, MD, PhD, of the Policlinico San Donato, Milan, Italy, and colleagues analyzed data from the DISCOVER registry, which is enrolling patients with logistic EuroSCORE of at least 20 and other high surgical risk factors such as prior CABG, CAD, and chronic kidney disease at 28 European sites.
The Direct Flow Medical valve (Direct Flow Medical) has a non-metallic design and a pressurized support structure that allows precise positioning and retrieval. It is approved in Europe but remains an investigational device in the United States.
Out of 375 patients enrolled thus far, 172 have 1-year follow-up available, De Marco told TCT Daily. Most received a 25-mm or 27-mm valve, with fewer receiving a 23-mm or 29-mm valve.
At 1 year, 84% of patients were categorized as NYHA class I or II. The degree of paravalvular leak was described as none/trace in 85% and mild or less in 95%. According to Kaplan-Meier analysis, freedom from all-cause mortality, cardiovascular mortality and stroke were 82%, 90% and 95%, respectively.
Thus, “the incidence of paravalvular leak continues to be low,” De Marco noted, and clinical improvement “is also sustained.”
Building the evidence base
According to De Marco, these results “stand on the shoulders” of the DISCOVER pre-market study, which released 2-year results with the same device earlier this year at EuroPCR 2015. In that trial, the survival rate of 80% compared favorably with that of other studies of extreme-risk patients, he said.
“The DISCOVER Registry evaluates the valve’s performance in real-world patients which are normally excluded by protocol from clinical studies,” De Marco said. “In our daily practice, we see and have to treat many of these patients. To see the consistency between valve performance in the real world and the outstanding results from the DISCOVER pre-market trial is, therefore, quite reassuring.” He said, adding that he particularly expects the low incidence of mild or higher paravalvular regurgitation to persist in longer-term outcomes.
De Marco credits the device’s design for its ease of implantation and good outcomes. Procedures can be done without the use of contrast, minimizing the risk of kidney injury, which is an especially important advantage for those with compromised renal function. “I particularly value the versatility and the easy positionability of the device, which allows a very controlled procedure with the possibility of safe retreat if necessary,” De Marco said.
- De Marco reports serving as a consultant for Direct Flow Medical.