TABLE 2.

Factors Contributing to Coronary Obstruction Risk

Leaflet characteristics	Leaflets longer than coronary ostial height and sinotubular junction height Leaflet calcific masses that can be displaced into coronary ostia Leaflet thickness that compounds TAVR frame displacement Leaflet retraction expected after TAVR, such as porcine bioprostheses, reduces obstruction risk
Sinus of Valsalva factors	Low-lying coronary ostia (<12 mm) (1,5) Narrow (deficient) sinus of Valsalva Low sinotubular junction height Previous aortic root repair (e.g., graft and coronary implantation) Phasic change in sinus dimensions (i.e., systole versus diastole)
Bioprosthetic valve factors	Bioprosthetic configuration (i.e., leaflets outside surgical stent frame, supra-annular vs. annular, angulation with regard to aortic root) Bioprosthetic frame height with respect to sinotubular junction Frame, skirt, and leaflet bulk Outward frame displacement after fracture Long leaflets characteristic of stentless and homograft devices
Transcatheter valve factors	Transcatheter valve fabric skirt, which may be nonuniform around its circumference Transcatheter valve commissures and their rotational alignment Transcatheter valve frame outflow splay when inflow expansion is constrained; more pronounced in balloon-expandable valves High implantation, to avoid conduction defects Long valves (e.g., Evolut) possibly tilted by ascending aorta Small valve selected to treat small annulus

TAVR = transcatheter aortic valve replacement.