News
VIENNA – Routine use of CT or three-dimensional echocardiography before and during transcatheter aortic valve replacement has contributed to a dramatic drop in paravalvular leaks, the procedure’s Achilles heel, based on the experience at a single, high-volume U.S. center.
In recent months, during testing of the SAPIEN 3 transcatheter aortic valve replacement (TAVR) system under development by Edwards, no patients developed moderate or severe paravalvular regurgitation during follow-up, and mild paravalvular leaks occurred at a rate of 7%-9%, Dr. Rebecca T. Hahn said at the annual meeting of the European Association of Cardiovascular Imaging. She and her associates tallied these rates recently at their institution, Columbia University Medical Center in New York, during their participation in PARTNER II , a multicenter study of the SAPIEN 3 device.
Dr. Hahn attributed these unprecedentedly low rates to three factors: preprocedure imaging with CT or 3-D echocardiography to select the best-sized valve for each patient, routine use of intraprocedural 3-D echo to guide precise valve placement and monitor for complications, and the SAPIEN 3 valve.
To put these regurgitation rates in context, in results from the pivotal CoreValve trial reported last May, the 30-day rate of moderate or severe paravalvular regurgitation was 9%, and the rate of mild paravalvular regurgitation was 36% ( N. Engl. J. Med. 2014;370:1790-8 ). The most recent data on paravalvular leak reported from a large trial using a SAPIEN valve currently on the U.S. market was from the PARTNER II trial of inoperable patients, which documented a roughly 20% rate of moderate or severe paravalvular regurgitation using either the SAPIEN XT or the original SAPIEN system.
Dr. Hahn acknowledged that one major factor contributing to the disappearance of moderate or severe leaks following TAVR was the design of the new SAPIEN 3 TAVR valve she is working with, which features a flexible layer around the outer perimeter of the valve to better seal it into the patient’s aortic valve annulus and prevent blood from leaking through gaps around the edge.
But she also credited intraprocedural 3-D echo as a major factor in the improved outcomes, as well as the use of CT or 3-D echo to accurately size the annulus before TAVR starts so that the patient’s annulus size can be matched with the most appropriately sized replacement valve.
“Each valve has a sweet spot” for the annulus size it will fit into, and CT imaging of the annulus to measure the size, or using three-dimensional echo when CT is not good enough, is the way that TAVR heart teams now make sure they use the valve size with a sweet spot for the patient receiving the valve, said Dr. Hahn, director of invasive and valvular echocardiography at Columbia. A key task for either imaging method is to measure annulus size on the “virtual” annular plane, a plane that is challenging to identify as it is defined by only the three hinge points of the aortic valve’s leaflets. “Three-dimensional echo allows us to quantify [annular size] in ways that we couldn’t before,” she said in an interview.
During the procedure, 3-D echocardiography is the only good imaging option. In addition to clarifying unusual morphologies of the annulus and surrounding tissues and blood vessels, and giving precise information on wire and valve placement, 3-D echo allows for rapid assessment of a hemodynamic emergency if one occurs during a TAVR procedure. Three-dimensional echo also affords the best way to assess the location and severity of paravalvular regurgitation. 3-D echo “allows us to make decisions during the procedure on what to do about paravalvular regurgitation,” Dr. Hahn said.
On Twitter @mitchelzoler