EXPERT ANALYSIS FROM EuroPCR
PARIS (FRONTLINE MEDICAL NEWS) – Thought leaders in interventional cardiology have been quick to throw cold water on recent reports of valve leaflet thickening and abnormal leaflet motion being detected in roughly 10% of patients after transcatheter aortic valve implantation (TAVI) or surgical aortic valve replacement.
“The take home message for the interventional community is there is no need for clinicians to modify their practice in relation to patient selection, TAVI implantation, or follow-up protocols. Specifically, there is no role for systematic CT or transesophageal echocardiographic follow-up of asymptomatic TAVI patients because they’re not at clinical risk, and these additional procedures carry risk in themselves,” Dr. Bernard Prendergast said at the annual congress of the European Association of Percutaneous Cardiovascular Interventions.
“Whilst there is room here for speculation and conjecture, I think most of us are confident that some of these findings may represent imaging artifact or reflect the natural history of biological valve leaflets, which has never been examined in such detail in the past,” added Dr. Prendergast, director of the cardiac structural intervention program at Guys and St. Thomas’ Hospital in London and cochair of the special EuroPCR session devoted to the emerging data on valve leaflet abnormalities.
The session featured three separate studies totaling 345 patients who underwent sophisticated, high-resolution 4D CT imaging or transesophageal echocardiography 5 days or more following TAVI or, less frequently, after surgical aortic valve replacement. Roughly 10% of patients showed a spectrum of leaflet abnormalities: thickening, mildly impaired motion, and/or thin films believed to be thrombi.
The leaflet abnormalities weren’t associated with any particular valve. And, as was emphasized by Dr. Prendergast and other speakers, to date these abnormalities haven’t been associated with a single case of stroke, systemic embolism, or valve failure.
Indeed, more than 100,000 TAVI procedures have been performed worldwide, and stroke rates in contemporary randomized trials and large registries are in the 1%-2% range. That’s better than with surgical valve replacement, Dr. Prendergast observed.
“Nowadays we can see much more than we could in the past, when we worked with 2D echocardiography,” observed discussant Dr. Jeroen J. Bax , professor of cardiology and director of noninvasive cardiology imaging at Leiden (the Netherlands) University Medical Center. “We see things that we do not completely understand. We could say that technology has outpaced our clinical understanding. But although we see things, at the moment there is no consequence in terms of hemodynamic performance or clinical outcomes. And this phenomenon of leaflet thickening has been occurring with surgical aortic valve replacement for many, many years and we simply didn’t realize it.”
Dr. Franz-Josef Neumann , who led one of the three studies, reported that 4D CT on day 5 post TAVI revealed leaflet abnormalities, all completely asymptomatic, in 16 of 154 patients. Two-thirds of the study population were on dual antiplatelet therapy at the time, the rest on a single antiplatelet agent. Dual antiplatelet therapy didn’t protect against leaflet thickening or other abnormalities.
All 16 affected patients were placed on an oral vitamin K antagonist with a target international normalized ratio (INR) of 2.5-3.5. To date, 11 of the 16 have undergone follow-up high-resolution CT after a median of 77 days. The leaflet thickening was resolved in all instances, according to Dr. Neumann, medical director of the department of cardiology and angiology at the University of Freiburg (Germany).
Dr. Raj R. Makkar presented a study of 125 patients who underwent high-resolution imaging after TAVI. Importantly, none of those who were on warfarin as part of their post-TAVI regimen developed leaflet abnormalities.
But he cautioned his colleagues against overreacting to the studies he and Dr. Neumann presented by placing all of their TAVI patients on an oral anticoagulant. He noted that the current TAVI population is elderly and laden with many comorbid conditions, placing them at high risk for bleeding complications.
There is at present no standard, guideline-recommended antiplatelet/antithrombotic regimen for before, during, or after TAVI. Working out the optimal protective drug regimen in this population is now a priority in light of the leaflet abnormality findings, but it will take time and require careful study, said Dr. Makkar, associate director of the Cedars Sinai Heart Institute in Los Angeles.
“Everyone is talking about anticoagulation as the imminent solution. But I want to emphasize that it comes with a price in terms of bleeding. These images are beautiful in terms of spatial resolution, but we must resist our temptation while the industry works on designing less thrombogenic valves,” the cardiologist added.
Discussant Dr. Christoph K. Naber confessed he was “stunned” by the images of leaflet abnormalities.
“Although we haven’t seen any clinical consequences, we have to keep in mind that the group of patients is still small. We have very good experience with TAVI; it has saved the lives of many patients. We know it’s a very good therapy. But if we believe we can go further and offer it to younger, lower-risk patients who will have their device for a longer time, then we should take the time and money to understand what is going on here and what consequences it could have. It’s something we should closely watch, especially if we want to extend the indication,” said Dr. Naber, director of the department of cardiology and angiology at the Contilia Cardiovascular Center in Essen, Germany.
He disclosed that he serves as a consultant to Abbott Vascular, Biotronik, Medtronic, and The Medicines Company. Dr. Makkar has received research grants from Edwards Lifesciences, St. Jude Medical, and Boston Scientific. Dr. Prendergast is on the speakers’ bureau for Edwards Lifesciences.
