Bicuspid Aortic Valve Classification and Management
Primary Morphological Classification
- Bicuspid aortic valves are classified into three primary morphological types based on cusp fusion patterns: fused BAV (90-95% of cases), 2-sinus BAV (5-7%), and partial-fusion BAV, with the most common subtype being right-left coronary cusp fusion (70-80% of all BAV) 1, 2
- Right-left coronary cusp fusion (Type 1) accounts for 70-80% of all BAV cases, resulting in a larger anterior cusp and smaller posterior cusp, with both coronary arteries typically arising from the anterior cusp 1, 3, 4, 5
- Right-noncoronary cusp fusion (Type 2) represents 20-30% of BAV cases, producing a larger right cusp than left cusp, with one coronary artery arising from each cusp 1, 3, 4, 5
- Left-noncoronary cusp fusion (Type 3) is the rarest fusion pattern at 3-6% of cases 1, 2
Associated Aortopathy Phenotypes
- Each valve morphology can be associated with three distinct aortopathy patterns: ascending phenotype (70-75%), root phenotype (15-20%), and extended phenotype (5-10%) 1, 2
- Ascending phenotype is characterized by dilatation predominantly at the tubular (supra-coronary) tract 1, 2
- Root phenotype is characterized by dilatation predominantly at the sinuses of Valsalva, more commonly associated with right-left fusion 1, 2
Diagnostic Approach
- The diagnosis is most reliable when two cusps are visualized in systole with only two commissures framing an elliptical systolic orifice on short-axis transthoracic echocardiography 4, 7
- Short-axis systolic view is the primary diagnostic view showing two cusps instead of three 7
- Only two commissures are visible with an elliptical (not stellate) systolic orifice 4, 7
- CMR demonstrates higher accuracy for valve morphology assessment compared to TTE (96% vs 73%) when compared to pathology specimens 5