Considerations for Optimal Device Selection in TAVR
Karen M Kim, MD
The following are key points to remember from this review on
considerations for optimal device selection in transcatheter aortic
valve replacement (TAVR):
1. There are several devices from
which to choose when performing TAVR for aortic stenosis (AS). Food and
Drug Administration (FDA)-approved current-generation devices include
SAPIEN 3, SAPIEN 3 Ultra, Evolut PRO+, and LOTUS Edge. Devices currently
under clinical investigation include ACURATE neo2 and Portico, also the
JenaValve and J-valve, which can be used in aortic insufficiency. The
devices have different characteristics with regard to expansion (balloon
vs. self vs. mechanically expandable), intra- vs. supra-annular leaflet
position, repositionability, frame material, leaflet tissue, and sheath
sizes.
2. Factors to consider in TAVR
device selection include: TAVR valve hemodynamics and long-term
durability, annular size, aortic valve and aortic root calcification,
vascular access and complications, risk of new persistent conduction
abnormalities, coronary re-access and risk of coronary occlusion,
bicuspid aortic valves, and valve-in-valve TAVR.
3. TAVR Valve Function and
Long-Term Durability: Hemodynamic parameters, including mean gradient
(MG), effective orifice area (EOA), and paravalvular leak (PVL) differ
among devices. Current literature has shown lower MG and larger EOA in
supra-annular self-expanding valves. Long-term durability of TAVR
devices beyond 5 or 6 years has not yet been established. Incidence and
degree of PVL varies between devices but incidence of moderate and
severe PVL have decreased with all current-generation devices, which
have incorporated new design features to reduce PVL.
4. Annular Size: While TAVR
devices are available in a range of sizes (as assessed by annular area,
perimeter, or diameter), in small annuli a supra-annular valve may
result in superior hemodynamics and avoid patient-prosthesis mismatch
(PPM). In very large annuli, TAVR devices have been used beyond
manufacturer recommendations.
5. Aortic Valve and Aortic Root
Calcification: While TAVR devices require leaflet calcification to
anchor in place, in patients with significant annular or left
ventricular outflow tract calcification, TAVR may result in significant
PVL. Also, heavy calcification has been associated with annular rupture,
particularly with oversized valves. In patients with thickened but not
calcified leaflets, the JenaValve or J-valve, which affix to the native
leaflets by a clipping mechanism, may be ideal.
6. Vascular Access and Vascular
Complications: Smaller sheath size is associated with reduction in
bleeding and vascular complications, especially in patients with small
femoral artery diameter.
7. Risk of New Persistent
Conduction Abnormalities. Need for new permanent pacemaker implantation
(PPI) depends on patient characteristics, valve type, and valve
deployment technique. There is “trade-off” between degree of PVL and
need for new PPI, as PVL may be reduced by greater radial force of the
TAVR device on the annulus, but greater force on the conduction system
increases risk of PPI. Device choice and implantation depth may need to
be altered for patients with underlying risk factors (right bundle
branch block, shorter membranous septal length).
8. Coronary Re-access and Risk of
Coronary Occlusion: Coronary re-access in patients with coronary artery
disease (CAD) or who develop CAD is affected by anatomic factors
(sinotubular junction dimensions, sinus height, leaflet length and
bulkiness, sinus of Valsalva width, and coronary ostial height), device
factors (commissural tab orientation, sealing skirt height, device frame
height), and procedural factors (deployment depth). Algorithms/apps on
coronary re-access for angiography or percutaneous coronary intervention
have been developed. In patients at risk for acute coronary
obstruction, a retrievable or repositionable TAVR device may be
preferable.
9. Bicuspid Aortic Valve (BAV): In
patients with BAV, leaflet asymmetry, presence of a raphe, variable
leaflet calcification, left ventricular outflow tract calcification, and
sometimes large annular dimensions may hinder optimal TAVR positioning
and expansion, resulting in increased risk of PVL. Several
propensity-matched studies have shown conflicting data for outcomes of
TAVR in bicuspid versus tricuspid AS. There are no data supporting one
TAVR device type over another for patients with BAV and AS, but clinical
trials are ongoing.
10. Valve-in-Valve (ViV) TAVR:
Optimal device selection for ViV TAVR requires identifying the mechanism
of prosthetic valve failure: elevated gradients from structural valve
degeneration vs. PPM vs. both. If PPM, ViV TAVR with a self-expanding
valve may be more favorable in small bioprosthetic prostheses. Balloon
fracture of the stent frame of certain prosthetic valves is an option to
facilitate ViV TAVR with a larger device for better EOA. Incidence of
acute coronary obstruction in ViV TAVR is higher and careful analysis on
TAVR protocol computed tomography scan or 3D models should be
performed. BASILICA (Bioprosthetic or Native Aortic Scallop Intentional
Laceration to Prevent Iatrogenic Coronary Artery Obstruction During
TAVR) or pre-emptive coronary protection are adjunctive techniques.
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