A new classification system sorts bicuspid valves according to anatomical categories centered on transcatheter aortic valve replacement (TAVR, also known as TAVI), as described by an international team.
While other systems, such as Sievers and the BAV consortium classifications, are available, Hasan Jilaihawi, MD, of Cedars-Sinai Heart Institute in Los Angeles, and colleagues reported in JACC: Cardiovascular Imaging on a simplified classification dividing these valves by leaflet appearance:
- Tricommissural, in which one commissure is completely fused between two cusps at or close to the commissural level
- Bicommissural raphe, in which two cusps are fused by a fibrous or calcified ridge that does not reach the height of the commissure, with fusion at or near the basal third of the sinus
- Bicommissural non-raphe, in which two cusps are completely fused from their basal origin by no visible seam
All three subtypes shared similarly low rates of 30-day mortality (3.8%) and cerebrovascular events (3.2%) after TAVR.
However, the predictors of paravalvular aortic regurgitation after TAVR were intercommissural distance for bicommissural bicuspids (odds ratio [OR] 1.37, 95% CI 1.02-1.84) and a lack of baseline CT for annular measurement (OR 3.03, 95% CI 1.20-7.69).
“Bicuspid as a description is -- itself -- a misnomer, since several bicuspid morphologies have three cusps (e.g., those with a raphe or tricommissural bicuspids); bileaflet is more accurate,” they wrote.
Jilaihawi’s data contrast with that of surgical aortic valve replacement, in which no difference in clinical outcomes has been seen between bicuspid phenotypes.
Also important was the use of CT, which beats 2D and 3D transesophageal echocardiography in image resolution. “CT is thus the preferred modality, for morphology delineation, calcium characterization and quantification and can also optimally assess for aortopathy.”
“Just as for TAVI in tri-leaflet aortic valves, a CT-guided assessment should be an integral part of procedural planning, but is especially important given the heterogeneity of bicuspid aortic valve morphological phenotypes that has significant potential to influence outcome,” according to the investigators.
Jeffrey J. Popma, MD, and Ronnie Ramadan, MD, both of Beth Israel Deaconess Medical Center in Boston, noted the importance of a anatomic classification system.
“As the transcatheter heart valve technology continues to rapidly advance and potentially move to lower risk patients, creating a morphologic classification system that can predict outcomes with TAVR and enhance case planning will become critical,” the pair wrote in an accompanying editorial.
The study included 130 patients from 14 centers, among which regional differences in bicuspid anatomy emerged. Bicommissural bicuspids accounted for 68.9% of those treated in North America, 88.9% in Europe, and 95.5% in Asia (P=0.003), with the rest being tricommissural valves. Among those cases, nonraphe type valves made up 11.9% of patients in North America, 9.4% in Europe, and 61.9% in Asia (P<0.001).
“A raphe, particularly if calcified, may influence TAVI expansion and apposition at the annular level,” they suggested.
Paravalvular aortic regurgitation was moderate or worse for 18.1% of patients; this was less common in those with pre-procedural CT (11.5%). This cohort also had less paravalvular aortic regurgitation with balloon-expandable valves and required less post-dilatation with self-expanding designs.
Balloon-expandable and self-expanding devices were both tied to new permanent pacemaker placement (25.5% versus 26.9%, P=0.83).
“In this multicentric study, TAVI achieved favorable outcomes in patients with preprocedural CT, with the exception of high permanent pacemaker rates for all devices and morphologies,” the investigators concluded.
Jilaihawi declared consulting for Edwards Lifesciences, St. Jude Medical, and Venus Medtech.
Popma disclosed relationships with Medtronic, Boston Scientific, Direct Flow Medical, and Abbott Vascular.
Ramadan reported no relevant conflicts of interest.
JACC: Cardiovascular Imaging
Jilaihawi H, et al “A bicuspid aortic valve imaging classification for the transcatheter aortic valve implantation era” JACC Cardiovasc Img 2016; DOI: 10.1016/j.jcmg.2015.12.022.
JACC: Cardiovascular Imaging
Popma JJ, et al “Computed tomographic imaging of bicuspid aortic valve disease for transcatheter aortic valve replacement” JACC Cardiovasc Img 2016; DOI: 10.1016/j.jcmg.2016.02.028.