The study is actually before June 2015 taking place before the Portico was cleared to resume trials.
Basically what happened was that the Portico TAVR valve had observations of reduced leaflet movement. It was found via CT scans to be caused by basically a blood clot forming on the outside of the valve leaflet and thus reduced its mobility. Not a permanent reduction or decay. The Portico trials was stopped and subsequently a study of 55 valves with usable CT scans out of 88 originally looked at, all were TAVR types. Along with 132 valves from a few other current data studies. Most were TAVR valves, and 27 were surgically implanted. Of those 27 surgical implanted valves, two had the same limited movement due to a blood clot on the leaflet.
The trials were cleared basically with this finding stated in this release about the FDA clearance:
http://www.ptca.org/news/2015/0603_STJUDE_PORTICO.html
"The bottom line is that, although this thickening leaflet and mobility issue had only been observed in the Portico trial, it seems to be a class effect across all device models, including surgical valve replacements. The incidence is rare and is treatable with medication..."
From the NEJM article:
With 21 of the clotted valves, 11 were subsequently treated with anticoagulation and 10 did not. all 11 treated valves had the clot dissolved and the leaflet motion resumed to its normal movement. In the ten cases left without anticoagulation, 1 of the valves returned to normal.
The studies found no correlation of stroke to these clotting incidents as most were within 1 day of the TAVR implantation.
The stroke observations quoted from theNEJM article:
"The finding that patients with reduced leaflet motion in the registries had a higher incidence of strokes or TIAs than did those with normal leaflet motion is preliminary and inconclusive. Overall, only six neurologic events were observed (two strokes in the PORTICO IDE study and one stroke and three TIAs in the registries), and all strokes occurred within 1 day after the TAVR procedure and before four-dimensional CT was performed. It is more likely that these first-day strokes were related to the procedural aspects of TAVR rather than to leaflet thrombosis. The cause of strokes or TIAs after TAVR is multifactorial and includes embolization of both thrombotic and nonthrombotic material from aortic, left ventricular, or native-valve instrumentation and new or preexisting atrial fibrillation, in addition to thromboembolism from bioprosthetic leaflets..."
