SAN FRANCISCO – The newly discovered issue of reduced leaflet motion and possible thrombus on bioprosthetic aortic heart valves, called by one expert “an imaging observation of uncertain clinical significance,” nonetheless drew lots of attention at the Transcatheter Cardiovascular Therapeutics annual meeting. Reduced leaflet motion was the focus of the meeting’s opening session as well as a specially scheduled press conference.
Much of the attention dealt with clarifying the situation and calling for calm after patient concerns were aroused by a report on Oct. 5 that examination of detailed CT scans from small series of patients who had recently undergone aortic valve replacement showed reduced-motion or immobilized valve leaflets on some of the bioprosthetic valves. The pattern of the finding, made using four-dimensional CT imaging, indicated that reduced-motion leaflets did not occur, and possibly even resolved, when patients were on anticoagulant therapy, suggesting that leaflet immobilization involved thrombus. Also, reduced-motion leaflets appeared following both transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR), said Dr. Raj R. Makkar.
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Dr. Raj R. Makkar
Dr. Makkar summarized his CT findings in several talks during the meeting and also in a report published a few days before the meeting (N Engl J Med. 2015 Oct 5. doi: 10.1056/NEJMoa1509233).
“We started with what we thought was an imaging artifact and established that is it real. We also established with reasonable certainty that it is related to thrombus,” said Dr. Makkar, professor at the University of California, Los Angeles, and director of the Cardiovascular Interventional Center at Cedars-Sinai Medical Center in Los Angeles. The evidence also indicates that this is a class effect that occurs with all types of TAVR systems as well as surgically placed valves.
What the evidence so far does not indicate is that patients with reduced-motion leaflets face any clinical consequence nor need for routine CT imaging of a newly-placed TAVR or SAVR valve. Also no need for routine anticoagulant therapy instead of standard treatment with dual antiplatelet therapy for several months following placement of a bioprosthetic aortic valve. “We should not make the leap that following TAVR, everyone should be on an anticoagulant” because anticoagulant treatment carries it own risks, said Dr. Makkar, who noted that roughly a quarter of TAVR patients receive anticoagulant treatment because of another indication, such as atrial fibrillation.
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Dr. Susheel Kodali
“The study did not show a temporal or causal relationship between the imaging findings and stroke. That needs emphasis,” commented Dr. Susheel Kodali, codirector of the Heart Valve Center at the Center for Interventional Vascular Therapy at Columbia University in New York. The possible link between leaflet immobility and strokes or other neurologic events “warrants further study,” as the data that Dr. Makkar reported involved a total of only six strokes or transient ischemic attacks. Data from all the TAVR trials and registries reported so far showed “no late signal of stroke,” said Dr. Kodali, who added that SAVR had a 30-year record of net benefit for appropriate patients.
Dr. Martin B. Leon
“Is valve-leaflet thickening an important controversy or much ado about nothing?” wondered Dr. Martin B. Leon, director of the Center for Interventional Vascular Therapy of Columbia University.
“Patients should not feel at risk, and there is no need to do anything differently” for the time being in routine practice, commented Dr. Jeffrey J. Popma, professor at Harvard Medical School and director of interventional cardiology at Beth Israel Deaconess Medical Center, both in Boston.
Dr. Jeffrey J. Popma
Dr. Makkar said that in the days following the publication of his report, he had “a lot of phone calls and time spent allaying anxiety in patients and reassuring them.”
One reason why these leaflet-motion abnormalities may have shown up on CT examinations recently is that “the cameras have gotten better,” said Dr. Jonathon A. Leipsic, codirector of advanced cardiac imaging at the Providence Health Care Heart Center at St. Paul’s Hospital in Vancouver. Dr. Leipsic also highlighted that with state-of-the-art CT images, immobilized leaflets are easy to identify.
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Dr. Jonathon A. Leipsic
Despite that, Dr. Popma stressed that standardized imaging protocols are needed going forward to produce reliable incidence data.
The data that Dr. Makkar reported came from a review of four-dimensional CT imaging done on 187 replacement aortic valves, usually within 3 months of placement. Images for 55 aortic valves came from the device-approval trial for a new TAVR system, taken 30 days after patients underwent TAVR with any of three types of systems. The images showed reduced leaflet motion in 22 valves (40%).