Transesophageal echocardiographic description of the mechanisms of aortic regurgitation in acute type A aortic dissection: implications for aortic valve repair
Herman D. Movsowitz, MDa,
Robert A. Levine, MD, FACCa,
Alan D. Hilgenberg, MD, FACCb and
Eric M. Isselbacher, MD, FACCa
a Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Boston, Massachusetts, USA
b Thoracic Aortic Center, Massachusetts General Hospital, Boston, Massachusetts, USA
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Figure 1 Mechanisms of functional aortic regurgitation in type A aortic dissection: Panel A is a schematic of normal aortic valve anatomy in the short-axis view (left) and long-axis view (right). The dotted lines represent the attachment of the leaflet tips to the sinotubular junction. Note that the leaflet tips coapt fully in diastole (short-axis view) and that the diameter of the sinotubular junction is similar to that at the base of the annulus. Panel B shows incomplete leaflet closure that occurs when the sinotubular junction dilates (arrows) relative to the aortic annulus resulting in leaflet tethering and a persistent diastolic orifice. This is usually best visualized in the short-axis view but may also be seen in the long-axis view if it is optimally aligned. Panel C shows aortic leaflet prolapse that occurs when the dissection extends into the aortic root and disrupts normal leaflet attachments to the aortic wall, thereby resulting in abnormal leaflet coaptation and eccentric AR. This is usually best visualized in the long-axis view where one or more leaflets are seen prolapsing into the left ventricular outflow tract in diastole. Panel D shows dissection flap prolapse that occurs when a redundant dissection flap prolapses through intrinsically normal aortic leaflets resulting in AR that is often short-lived and may be intermittent. The regurgitant flow occurs through the funnel shaped by the dissection flap.
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Figure 2 Incomplete leaflet closure is characterized by a persistent diastolic orifice that is best visualized in the short-axis view of the aortic leaflets, usually obtained at approximately 45° by multiplane TEE. It is important to find the short-axis plane in which the diastolic orifice appears smallest so as to avoid overestimation of the size of the persistent diastolic orifice. The top panel shows the short-axis view of the aortic valve leaflets in systole; the bottom panel shows the persistent valve orifice in diastole. It should be noted that a persistent diastolic orifice can be visualized in the long-axis view when it is optimally aligned. However, off-axis views in the longitudinal plane can falsely create the appearance of incomplete leaflet closure. We therefore recommend the more reliable short-axis view.
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Figure 3 Aortic leaflet prolapse is best visualized in a long-axis view of the aortic valve, aortic root and ascending aorta, which is usually obtained at approximately 120° by multiplane TEE. The top panel shows a long-axis view of the aortic valve and aortic root. The long narrow gray arrows point to an intimal dissection flap that extends into the aortic root. The broad white arrow points to right coronary cusp that is prolapsing into the left ventricular outflow tract behind the noncoronary cusp, seen above. The bottom panel shows an eccentric jet of severe AR that is directed posteriorly into the left ventricular outflow tract. AO = aorta; LA = left atrium; LVOT = left ventricular outflow tract.
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Figure 4 Dissection flap prolapse can be visualized by mutiplane TEE in the short-axis and long-axis views at 45° and 120°, respectively. The top panel is a short-axis view of the aortic valve at the onset of diastole. The arrows point to the three aortic leaflets; a dissection flap is seen prolapsing through the center of the aortic leaflets. The bottom panel is a long-axis view of the aorta showing the dissection flap prolapsing through the plane of the aortic valve.
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