The bicuspid aortic valve: an integrated phenotypic classification of leaflet morphology and aortic root shape.

OBJECTIVE

To establish a classification of bicuspid aortic valve (BAV) that includes both leaflet morphology and aortic shape.

SETTING

Two academic medical centres of the University of Washington, Seattle.

PATIENTS

191 adult patients with BAV.

INTERVENTIONS

Review of clinical data and transthoracic echocardiograms.

MAIN OUTCOME MEASURES

Assessment of leaflet morphology; valve function; aortic shape and dimensions.

RESULTS

We identified three morphologies: type 1, fusion of right and left coronary cusp (n = 152); type 2, right and non-coronary fusion (n = 39); and type 3, left and non-coronary fusion (n = 1). Comparing type 1 and 2 BAV, there were no significant differences in age, height, weight, blood pressure or aortic valve function. Type 1 was more common in men (69 vs 45%). The aortic sinuses were larger in type 1, while type 2 had larger arch dimensions. Myxomatous mitral valves were more common in type 2 BAV (13% vs 2.6%, p<0.05). Three aortic shapes were defined: normal (N), sinus effacement (E), and ascending dilatation (A). Comparing type 1 to type 2 BAV, shape N was more common in type 1 (60% vs 32%), and type A was more common in type 2 (35% vs 54%,); type E was rare (p<0.01 across all groups).

CONCLUSION

A comprehensive BAV phenotype includes aortic shape. Type 1 BAV is associated with male gender and normal aortic shape but a larger sinus diameter. Type 2 leaflet morphology is associated with ascending aorta dilatation , larger arch dimensions and higher prevalence of myxomatous mitral valve disease.