Bicuspid Aortic Valve Area in Normal Heart

Introduction: Bicuspid aortic valve (BAV) is a common congenital valve abnormality. Subjects with BAV are at increased risk for valve malfunction. There is no data in the literature regarding the range of aortic valve area in normal functioning BAV. Thus, we aimed to evaluate the normal range of BAV area.

Methods: Patients with a diagnosis of BAV were identified from Sheba medical center echocardiographic data base. Inclusion criteria were normal tissue leaflets appearance and normal functioning valve in the presence of normal echocardiogram. Echocardiographic data were collected. Aortic valve area (AVA) was measured with both planimetry and using the continuity equation. Hemodynamics and patients size were recorded as well.

Results: The study group includes 50 healthy subjects with BAV (42 men, age 39±12 years). The group was characterized by large body surface area (1.88±0.25 m²). All studies were performed with normal hemodynamics (systolic blood pressure: 120±15 mmHg, heart rate: 74±22/min). As expected, type 1 valve morphology (right and left cusp fusion) was the most common morphology (82%), followed by type 2 (right and non-coronary fusion, 18%). Left ventricular outflow tract diameter measured 2.3±0.3 cm. The BAV group presented with a large AVA. Interestingly, measuring AVA using continuity equation has shown smaller values compared to planimetry (3±1.1 cm² vs 3.8±1.1 cm² respectively, P<0.001). This significant difference persist using indexed AVA (1.59±0.6/cm² vs 1.95±0.5/cm² respectively, p<0.001).

Conclusion: This data provide normal values for echocardiographically determined AVA in subjects with BAV. The BAV population was characterized by large body size and large AVA. The larger AVA measured with the planimetry emphasize the limitation of this method, especially for BAV population.