Variability of repairable bicuspid aortic valve phenotypes: towards an anatomical and repair-oriented classification†

Abstract

OBJECTIVES The bicuspid aortic valve (BAV) exists in a wide variety of valve phenotypes. The aim of this study was to assess the anatomical characteristics of the different phenotypes and develop a classification system to aid surgical repair. METHODS In 178 consecutive patients operated on for aortic insufficiency or aortic dilatation in 2 centres, 11 anatomical parameters of BAV were measured by echocardiography and intraoperatively. All BAV judged potentially repairable were included in the study. RESULTS Commissural orientation correlated positively with fusion length (R2 = 0.6, P < 0.001) and negatively with non-functional commissure height (R2 = 0.45, P < 0.001). The cohort was divided into 3 groups according to their commissural orientation (type A: symmetrical, 160–180°, n = 73; type B: asymmetrical, 140–159°, n = 74; and type C: very asymmetrical, 120–139°, n = 31). The patterns of cusp fusion, annulus and aortic size were similar among the groups. Fusion length and the geometric height of the cusps decreased from type A to C; non-functional commissure height increased from type A to C (P < 0.05). Patient age increased from type A to type C. Isolated aortic dilatation was more frequent in type A, and severe aortic insufficiency was more frequent in types B and C (P < 0.05). Valve repair techniques and management of commissural orientation varied among the 3 groups (P < 0.05). Aortic valve replacement and residual aortic insufficiency after repair were more frequent in type C (P < 0.05). CONCLUSIONS The BAV phenotypes follow a continuous spectrum that extends from symmetrical to very asymmetrical BAV. We describe the main anatomical parameters (including commissure orientation, length of fusion and non-functional commissure height) and their variation across this spectrum. We propose a new repair-oriented classification system based on those parameters that can be used to predict valve repair techniques. This classification needs further validation with regards to surgical techniques and long-term outcomes.

Bicuspid aortic valve repair: systematic review on long-term outcomes

“…Type A were patients who presented with symmetrical phenotype, type B were patients with asymmetrical phenotype and type C were patients with very asymmetrical phenotype which bordered on being similar to a tricuspid valve. Type C patients were more likely to have residual AR when compared to type A or B patients on discharge (36).…”

“…It was shown that commissural orientation was independently associated with risk for reoperation (11). Further, patients with very asymmetrical (120-139 degrees commissural orientation) were associated with greater need for aortic valve replacement and residual aortic regurgitation (36). There is theoretical concern that geometric orientation matters, because if not abiding by commissural alignment during repair there may be cusp distortion and stress, which may affect long term valve competence.…”

The 10 Commandments for Aortic Valve Repair

“…21 BAV is much more complex because of the anatomic variability. [12][13][14]22 The common denominator of all bicuspid valves is the fact that there are only 2 functional and normal commissures; a third commissure is almost always present but reduced in height, that is, hypoplastic (Fig. 2).…”

“…In decision-making for the optimal repair strategy, the anatomic variability must be considered, and a new classification has been proposed, which will facilitate the determination of appropriate repair strategies. 12 In effect, the best postrepair configurations in terms of hemodynamics and durability are either near-symmetric or tricuspid-like, that is, very asymmetric. The repair strategy will have to accommodate these aspects.…”

Commentary: Should we attempt to refine an already imperfect nature?

“…A more recent study has attempted to classify bicuspid aortic valves on the basis of their symmetric or asymmetric presentation. 1 This should help with more systematic surgical planning, better comparison of results, and improved prognostic evaluation.…”