Abstract
Aortic valve-sparing operations have become part of the surgical armamentarium to treat aortic root aneurysm and ascending aorta aneurysm with aortic insufficiency. Both types of procedures, remodeling of the aortic root and reimplantation of the aortic valve have provided excellent long term results when the procedure is correctly matched to the aortic root pathology.
Keywords
aortic root aneurysm, aortic insufficiency
Step 1
Surgical Anatomy of the Aortic Root
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The aortic root is the anatomic segment between the left ventricle and ascending aorta. From the surgical viewpoint, it consists of the aortic annulus (AA), aortic cusps, aortic sinuses, and sinotubular junction (STJ). Although the term aortic annulus may be anatomically incorrect, it is often used in surgical anatomy and pathology to describe the aortoventricular junction. Approximately 45% of the circumference of the AA is attached to muscular interventricular septum, and 55% is attached to fibrous tissue, as shown in Fig. 13.1 . This fibrous tissue is the membranous interventricular septum and the fibrous body that connects the anterior leaflet of the mitral valve to the aortic root.
Figure 13.1
Photograph of an aortic root.
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The AA is scalloped and attaches the aortic cusps to the aortic root and left ventricle. The portion of the AA corresponding to the noncoronary cusp is attached entirely to fibrous tissue, whereas the portions corresponding to the left and right coronary cusps are partially attached to fibrous tissue and partially to cardiac muscle. The highest point of the AA, where two cusps meet, is the commissure. The anatomic arrangement of the AA creates a triangular space beneath the cusps, termed the subcommissural triangle. There are three commissures and three subcommissural triangles. The STJ lies immediately above the commissures and separates the aortic root from the ascending aorta. The arterial wall contained between the AA and STJ creates the aortic sinuses, or sinuses of Valsalva. The three aortic cusps have a crescent shape and often are of different sizes, but the length of the base of a cusp is always 1.5 times longer than the length of its free margin (FM), as illustrated in Fig. 13.2 . Thus, a large cusp will have a proportionally longer base (AA), longer FM, longer intercommissural distance along the STJ, and larger aortic sinus. The noncoronary and right cusps and sinuses are often larger than the left cusp and left aortic sinus.
Figure 13.2
Geometric relationship among various components of the aortic root.
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The AA is a three-dimensional structure that evolves along three separate planes, as illustrated in Fig. 13.3A–C . Each aortic cusp is inserted in the annulus along a horizontal plane (see Fig. 13.3D ). For practical purposes, we usually refer to its diameter as the maximal distance at the level of its nadir.
Figure 13.3
The aortic annulu evolves along a cylinder.
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The relationship of the diameters of the AA at this level and at higher levels until reaching the commissures (STJ) varies with age. In children and young adults, the diameter of the AA is 15% to 20% larger than its diameter at the level of the commissures (STJ). As the elastic fibers of the arterial wall decrease with age, the STJ dilates and tends to become equal to the diameter of the lower AA in adults. However, the AA of each cusp evolves along a single horizontal plane (see Fig. 13.3 ).
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Ascending aortic aneurysms can cause aortic dissection or rupture when their transverse diameter exceeds 55 mm. Aneurysms of the ascending aorta can also cause dilation of the STJ, with consequent aortic insufficiency due to lack of coaptation of the cusps, as illustrated in Fig. 13.4 . One or more aortic sinuses may also become secondarily dilated, but the AA often remains normal. Patients with ascending aortic aneurysms and aortic insufficiency are usually in their sixth or seventh decade of life. If the aortic cusps are normal or minimally elongated along their FMs, it is possible to replace the ascending aorta with correction of the diameter of the STJ, replace one or more sinuses if necessary, repair the cusps if there is prolapse, and reestablish aortic valve competence.
Figure 13.4
Dilation of the sinotubular junction prevents the cusps from coapting and causes aortic insufficiency.
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Aortic root aneurysms usually start with dilation of the aortic sinuses and, with time, the dilation extends proximally into the AA and distally into the STJ. Patients with an aortic root aneurysm are usually in the second to fourth decade of life when they need surgery, and the aneurysm is often associated with genetic syndromes, such as Marfan syndrome, Loeys-Dietz syndrome, and others. The two subcommissural triangles of the noncoronary cusp flatten as the AA dilates, which decreases the coaptation area of the cusps and may cause aortic insufficiency ( Fig. 13.5 ). The indication for surgery is usually based on the diameter of the aortic sinuses and family history of aortic dissection. In most cases, surgery is recommended when the diameter reaches 50 mm and less if there is a family history of aortic dissection.
Figure 13.5
Dilation of the aortic annulus flattens the subcommissural triangles of the noncoronary cusp and pulls the belly of the cusps apart.
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This chapter reviews the operative techniques used to preserve the aortic valve in patients with ascending aortic aneurysm and aortic insufficiency, as well as patients with aortic root aneurysm, with or without aortic insufficiency. The term aortic valve-sparing operation was introduced to describe these procedures.
Step 1
Surgical Anatomy of the Aortic Root
- ◆
The aortic root is the anatomic segment between the left ventricle and ascending aorta. From the surgical viewpoint, it consists of the aortic annulus (AA), aortic cusps, aortic sinuses, and sinotubular junction (STJ). Although the term aortic annulus may be anatomically incorrect, it is often used in surgical anatomy and pathology to describe the aortoventricular junction. Approximately 45% of the circumference of the AA is attached to muscular interventricular septum, and 55% is attached to fibrous tissue, as shown in Fig. 13.1 . This fibrous tissue is the membranous interventricular septum and the fibrous body that connects the anterior leaflet of the mitral valve to the aortic root.
Figure 13.1
Photograph of an aortic root.
- ◆
The AA is scalloped and attaches the aortic cusps to the aortic root and left ventricle. The portion of the AA corresponding to the noncoronary cusp is attached entirely to fibrous tissue, whereas the portions corresponding to the left and right coronary cusps are partially attached to fibrous tissue and partially to cardiac muscle. The highest point of the AA, where two cusps meet, is the commissure. The anatomic arrangement of the AA creates a triangular space beneath the cusps, termed the subcommissural triangle. There are three commissures and three subcommissural triangles. The STJ lies immediately above the commissures and separates the aortic root from the ascending aorta. The arterial wall contained between the AA and STJ creates the aortic sinuses, or sinuses of Valsalva. The three aortic cusps have a crescent shape and often are of different sizes, but the length of the base of a cusp is always 1.5 times longer than the length of its free margin (FM), as illustrated in Fig. 13.2 . Thus, a large cusp will have a proportionally longer base (AA), longer FM, longer intercommissural distance along the STJ, and larger aortic sinus. The noncoronary and right cusps and sinuses are often larger than the left cusp and left aortic sinus.
Figure 13.2
Geometric relationship among various components of the aortic root.
- ◆
The AA is a three-dimensional structure that evolves along three separate planes, as illustrated in Fig. 13.3A–C . Each aortic cusp is inserted in the annulus along a horizontal plane (see Fig. 13.3D ). For practical purposes, we usually refer to its diameter as the maximal distance at the level of its nadir.
Figure 13.3
The aortic annulu evolves along a cylinder.
- ◆
The relationship of the diameters of the AA at this level and at higher levels until reaching the commissures (STJ) varies with age. In children and young adults, the diameter of the AA is 15% to 20% larger than its diameter at the level of the commissures (STJ). As the elastic fibers of the arterial wall decrease with age, the STJ dilates and tends to become equal to the diameter of the lower AA in adults. However, the AA of each cusp evolves along a single horizontal plane (see Fig. 13.3 ).
- ◆
Ascending aortic aneurysms can cause aortic dissection or rupture when their transverse diameter exceeds 55 mm. Aneurysms of the ascending aorta can also cause dilation of the STJ, with consequent aortic insufficiency due to lack of coaptation of the cusps, as illustrated in Fig. 13.4 . One or more aortic sinuses may also become secondarily dilated, but the AA often remains normal. Patients with ascending aortic aneurysms and aortic insufficiency are usually in their sixth or seventh decade of life. If the aortic cusps are normal or minimally elongated along their FMs, it is possible to replace the ascending aorta with correction of the diameter of the STJ, replace one or more sinuses if necessary, repair the cusps if there is prolapse, and reestablish aortic valve competence.
Figure 13.4
Dilation of the sinotubular junction prevents the cusps from coapting and causes aortic insufficiency.
- ◆
Aortic root aneurysms usually start with dilation of the aortic sinuses and, with time, the dilation extends proximally into the AA and distally into the STJ. Patients with an aortic root aneurysm are usually in the second to fourth decade of life when they need surgery, and the aneurysm is often associated with genetic syndromes, such as Marfan syndrome, Loeys-Dietz syndrome, and others. The two subcommissural triangles of the noncoronary cusp flatten as the AA dilates, which decreases the coaptation area of the cusps and may cause aortic insufficiency ( Fig. 13.5 ). The indication for surgery is usually based on the diameter of the aortic sinuses and family history of aortic dissection. In most cases, surgery is recommended when the diameter reaches 50 mm and less if there is a family history of aortic dissection.
