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ECHO FEATURES OF BICUSPID AORTIC VALVES

  • Definition

    • - Bicuspid aortic valve: two instead of three semilunar aortic valve cusps.

    • - There are also rare patients with unicuspid and quadricuspid aortic valves.

  • Cusp nomenclature

    • - The conjoined cusp is usually wider than normal and contains a raphe.

    • - Raphe: a ridge that extends from the aortic wall to the commissure of the conjoined cusp.

  • Raphe height variants

    • - No evident raphe, just a “fishmouth” systolic opening.

    • - Shallow, difficult-to-image raphe.

    • - Classic thick visible raphe.

    • - Unusually tall raphe—rising as high as the free edge of the leaflets.

  • Over time, the raphe may become calcified. Calcification is manifested on echo by acoustic shadowing past the raphe.

  • Classification:

    • - Type 1: Fusion of the right and left coronary cusp (larger sinus diameter) (70%–86% incidence).

    • - Type 2: Fusion of the right and noncoronary cusp (associated tubular ascending aorta and dilated arch) (12%–28% incidence).

    • - Type 3: Fusion of the left and noncoronary cusp (rare incidence).

  • Imaging:

    • - Parasternal long axis (PLAX) view provides the first clue to the presence of a bicuspid valve.

    • - Asymmetric diastolic leaflet closure line located on an “outside third” of the sinus of Valsalva (Fig. 9-1).

    • - Systolic doming.

    • - Diastolic prolapse.

  • Short axis (SAX) view is used for definitive diagnosis. Sometimes transesophageal echocardiography (TEE) is needed for confirmation.

  • Diastole may fool you: The closed valve may look perfectly normal on echo when a nonthickened raphe is present.

  • Look for a thicker than normal, partly unseparated raphe in systole.

  • Look for the systolic “fishmouth” opening.

  • A commissure line may continue “past the center” without bending.

  • A commissure may violate the 10–2–6 o’clock location.

  • When the intercoronary (right to left) commissure is abnormal (type 1), the systolic opening has a horizontal orientation.

  • When the right-to-noncoronary commissure is abnormal (type 2), the systolic opening has a vertical orientation.

  • Doppler evaluation of the systolic gradient in bicuspid aortic valves:

    • - The maximum instantaneous Doppler gradient is typically higher than a peak-to-peak gradient measured by catheterization.

    • - The mean Doppler gradient is closer to the peak-to-peak gradient measured by catheterization.

    • - The discrepancy is explained in some cases by the presence of pressure recovery.

    • - Direct planimetry of 2D and 3D echo images should be done when feasible (making sure the smallest possible, “mouth of the volcano,” true stenosis orifice is used).

    • - In children with a stenotic bicuspid, or a unicuspid aortic valve, the presence of left ventricular hypertrophy indicates significant valve obstruction.

    • - Bicuspid aortic valve is associated with coarctation of the aorta.

FIGURE 9-1

Bicuspid aortic valve. Eccentric leaflet closure.

Sources

  • Espinola-Zavaleta N, Muñoz-Castellanos L, Attié F, et al. Anatomic three-dimensional echocardiographic correlation of bicuspid aortic valve. J Am Soc Echocardiogr. 2003;16:46–53.

  • Michelena HI, Khanna AD, Mahoney D, et al. Incidence of aortic complications...

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