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David TE. Aortic Valve Repair and Aortic Valve-Sparing Operations.
In: Cohn LH, Edmunds LH Jr, eds. Cardiac Surgery in the Adult. New York: McGraw-Hill, 2003:811824.

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Chapter 31

Aortic Valve Repair and Aortic Valve-Sparing Operations

Tirone E. David

FUNCTIONAL ANATOMY OF THE AORTIC VALVE
AORTIC VALVE PATHOLOGY IN ADULTS
NATURAL HISTORY OF AORTIC VALVE DISEASE
????Aortic Stenosis
????Aortic Insufficiency
INDICATIONS FOR AORTIC VALVE SURGERY
????Aortic Stenosis
????Aortic Insufficiency
????Aortic Root Aneurysm
????Ascending Aortic Aneurysm
SELECTION OF PATIENTS FOR AORTIC VALVE SURGERY
TECHNIQUES OF AORTIC VALVE REPAIR
????Cusp Perforation
????Cusp Extension
????Cusp Prolapse
????Bicuspid Aortic Valve
AORTIC VALVE-SPARING OPERATIONS
????Ascending Aortic Aneurysm with Aortic Insufficiency
????Aortic Root Aneurysm
????????REMODELING OF THE AORTIC ROOT
????????REIMPLANTATION OF THE AORTIC VALVE
RESULTS OF AORTIC VALVE SURGERY
????Bicuspid Aortic Valve Repair
????Ascending Aortic Aneurysm with Aortic Insufficiency
????Aortic Root Aneurysm
REFERENCES

?? FUNCTIONAL ANATOMY OF THE AORTIC VALVE
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The aortic valve is a complex structure that is best described as a functional and anatomic unit called the aortic root. The aortic root has four components: aortic annulus, aortic cusps, aortic sinuses (sinuses of Valsalva), and sinotubular junction.

The aortic annulus unites the aortic cusps and aortic sinuses to the left ventricle. The aortic annulus is attached to ventricular myocardium (interventricular septum) in approximately 45% of its circumference and to fibrous structures (mitral valve and membranous septum) in the remaining 55% (Fig. 31-1). The aortic annulus has a scalloped shape. Histologic examination of the aortic annulus reveals that it is a fibrous structure with strands attaching itself to the muscular interventricular septum and has a fibrous continuity with the anterior leaflet of the mitral valve and membranous septum. The fibrous tissue that separates the aortic root from the mitral valve is called intervalvular fibrous body. An important structure immediately below the membranous septum is the bundle of His. The atrioventricular node lies in the floor of the right atrium between the annulus of the septal leaflet of the tricuspid valve and the coronary sinus. This node gives origin to the bundle of His, which travels through the right fibrous trigone along the posterior edge of the membranous septum to the muscular interventricular septum. At this point the bundle of His divides into left and right bundle branches that extend subendocardially along both sides of the interventricular septum.



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FIGURE 31-1 A photograph of a human open left ventricular outflow tract and aortic root. (Reproduced from David TE: Aortic valve repair for management of aortic insufficiency. Adv Card Surg 1999; 11:129, with permission from Mosby Inc.)

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The aortic cusps are attached to the aortic annulus in a scalloped fashion (see Fig. 31-1). The aortic cusps have a semilunar shape whereby the length of the base is approximately 1.5 times longer than the length of the free margin, as illustrated in Figure 31-2. There are three aortic cusps and three aortic sinuses: left, right, and noncoronary. The aortic sinuses are also referred to as sinuses of Valsalva. The left coronary artery arises from the left aortic sinus and the right coronary artery arises from the right aortic sinus. The left coronary artery orifice is closer to the aortic annulus than is the right coronary artery orifice. The highest point where two cusps meet is called the commissure, and it is located immediately below the sinotubular junction. The scalloped shape of the aortic annulus creates three triangular spaces underneath the commissures. The two triangles beneath the commissures of the noncoronary cusp are fibrous structures, whereas the triangular space beneath the commissure between the right and left aortic cusps is muscular. These three triangles are seen in Figure 31-1. The sinotubular junction is the end of the aortic root. It is an important component of the aortic root because the commissures of the aortic cusps are immediately below it.



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FIGURE 31-2 Geometric relationships of various components of the aortic root. The base of the aortic cusp is 1.5 times longer than its free margin. The diameter of the aortic annulus is 10% to 15% larger than the diameter of the sinotubular junction, but it tends to become equal with aging. Three semilunar cusps seal the aortic orifice. (Reproduced from David TE: Aortic valve repair for management of aortic insufficiency. Adv Card Surg 1999; 11:129, with permission from Mosby Inc.)

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The geometry of the aortic root and its anatomic components varies among individuals, but the geometry of these components is somewhat interrelated.14 For instance, the larger the aortic cusps, the larger are the diameters of the aortic annulus and sinotubular junction.4 The aortic cusps are semilunar (crescent shaped), their bases are attached to the annulus, the free margins extend from commissure to commissure, and the cusps coapt centrally during diastole. The size of the aortic cusps varies among individuals and within the same person, but as a rule the noncoronary cusp is slightly larger than the right and left. The left is usually the smallest of the three. Because of the crescent shape of the aortic cusps and the fact that their free margins extend from commissure to commissure, the diameter of the aortic orifice must be smaller than the length of the free margins. Indeed, anatomic studies of fresh human aortic roots demonstrated that the average length of the free margins of the aortic cusps was one-third longer than the diameter of the aortic orifice.1

The diameter of the aortic annulus is 15% to 20% larger than the diameter of the sinotubular junction in normal aortic roots of young persons, but these diameters tend to become equal in older ones. All components of the aortic root are very elastic and compliant in young patients but this compliance decreases with age as elastic fibers are replaced by fibrous tissue.

The aortic annulus, the aortic cusps, and the sinotubular junction play an important role in maintaining valve competence. On the other had, the aortic sinuses play no role in valve competence,5 but they are believed to be important in minimizing mechanical stress on the aortic cusps during the cardiac cycle.2


?? AORTIC VALVE PATHOLOGY IN ADULTS
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Anatomically normal aortic cusps may become calcified late in life and cause aortic stenosis. This type of lesion is called dystrophic calcification, senile calcification, or degenerative calcification. The range of histopathologic lesions includes calcification, chondroid and osseous metaplasia, neorevascularization, inflammation, and lipid deposition.6 The pathogenesis of this lesion is not well understood. Aging is certainly the most important epidemiologic factor.69 Degenerative calcification is an active inflammatory process with similarities and dissimilarities to atherosclerosis.79 Aging and high levels of lipoprotein a were found to be correlated with aortic valve sclerosis.7 Degenerative calcification of the aortic valve is the most common cause of aortic stenosis in elderly patients in North America.10,11

Bicuspid aortic valve is common and occurs in 1% to 2% of the population.12 It usually functions satisfactorily and does not cause hemodynamic problems until late in life when it becomes calcified and stenotic. Calcified bicuspid aortic valve is the second most common cause of aortic stenosis in elderly patients.10 Bicuspid aortic valve can also cause aortic insufficiency, particularly in young patients in whom mild to moderate dilation of the aortic root is often present.13 Most patients with bicuspid aortic valve have three aortic sinuses. The two cusps are of different sizes and the larger one often contains a raphe instead of a commissure. The raphe extends from the mid portion of the cusp to the aortic annulus, and its insertion in the aortic root is at a lower level than the other two commissures. Bicuspid aortic valves with two aortic sinuses and no raphe are uncommon. The right coronary artery is nondominant in most patients with a bicuspid aortic valve.

Unicusp aortic valve is another congenital anomaly of the aortic valve. It often contains only one commissure and causes aortic stenosis. Bicuspid and unicusp aortic valves are frequently associated with premature degenerative changes of the media of the aortic root and ascending aorta. They increase the risk of aneurysms and type A aortic dissection.14 Quadricusp aortic valve is a rare anomaly that may cause aortic insufficiency. Three of the four cusps are usually of similar size and the other is hypoplastic.

Subaortic membranous ventricular septal defect with aortic insufficiency is uncommon in adults. The interventricular septal defect causes distortion of the aortic annulus, and the right aortic cusp is often elongated and may prolapse and cause aortic insufficiency.

Dilation of the aortic root is the most common cause of aortic insufficiency in North America.1011 Older patients with ascending aortic aneurysm may develop aortic insufficiency because of dilation of the sinotubular junction. The aortic sinuses and aortic annulus may remain relatively normal in these patients. Aortic aneurysm in young patients usually begins with dilation of the aortic sinuses, which progresses into the sinotubular junction and ultimately the aortic annulus. Annuloaortic ectasia is a term used to describe dilation of the aortic annulus. Aortic root aneurysm is common in patients with Marfan syndrome.

Aortic dissections involving the ascending aorta can cause aortic insufficiency because of preexisting aortic root aneurysm or by detachment of one or more commissures with consequent prolapse of the cusps.15

Rheumatic aortic valve disease is still prevalent in developing countries. The rheumatic process causes fibrosis, thickening, and contraction of the aortic cusps, often with commissural fusion. In advanced cases, the valve becomes calcified. It is possible that some postinflammatory aortic valve lesions are not rheumatic in origin.16

Numerous connective tissue disorders (ankylosing spondylitis, osteogenesis imperfecta, rheumatoid arthritis, Reiter's syndrome, lupus, etc.) can cause aortic insufficiency. The anorexigenic drugs phentermine and fenfluramine can also cause aortic insufficiency.16


?? NATURAL HISTORY OF AORTIC VALVE DISEASE
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Aortic Stenosis

Several studies showed that asymptomatic patients with aortic stenosis have a good prognosis.17,18 Sudden death in asymptomatic patients is uncommon.18 However, when symptoms develop, the prognosis becomes poor and the average survival is 2 to 3 years for patients with symptoms of angina or syncope, and 1 to 2 years for those who develop congestive heart failure.19

Aortic Insufficiency

The prognosis of symptomatic patients is poor with death occurring within 4 years after development of angina and within 2 years after the onset of congestive heart failure.20 Since aortic insufficiency may cause ventricular damage, asymptomatic patients should be operated on when ventricular function begins to deteriorate.


?? INDICATIONS FOR AORTIC VALVE SURGERY
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Aortic Stenosis

Patients with symptoms should be considered for surgery. Asymptomatic patients with an aortic valve area of less than 0.8 cm2 or a mean systolic gradient greater than 50 mm Hg with left ventricular hypertrophy should also be considered for surgery if it can be performed with low operative risk. An echocardiographic flow velocity across the aortic valve greater than 4 m/s is also indication for surgery.21

Aortic Insufficiency

Symptomatic patients should be operated on. Asymptomatic patients should also be operated on when left ventricular function begins to deteriorate.22

Aortic Root Aneurysm

Patients with aortic root aneurysm with or without Marfan syndrome should undergo surgery when the aortic root diameter reaches 55 mm.23 If an aortic valve-sparing operation is likely to be feasible, the operation is justifiable when the aneurysm reaches 50 mm in diameter.24 Patients with Marfan syndrome and a family history of aortic dissection should also have surgery when the diameter of the aortic root reaches 50 mm even if a valve-sparing procedure is not feasible.25

Ascending Aortic Aneurysm

Patients with ascending aortic aneurysm should undergo surgery when the transverse diameter reaches 60 mm.26 If moderate or severe aortic insufficiency is present and the valve is deemed repairable, surgery should be performed before the diameter reaches 60 mm to avoid further damage to the aortic cusps.


?? SELECTION OF PATIENTS FOR AORTIC VALVE SURGERY
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Only a small proportion of adult patients with aortic valve disease are candidates for aortic valve repair. Stenotic aortic valves, particularly senile calcific valves, are not suitable for aortic valve repair. However, mechanical decalcification of a mildly or moderately stenotic aortic valve is sometimes possible in patients in whom the primary indication for operation is myocardial revascularization. The calcific deposits should be limited to small segments of the aortic cusps and most areas should be free of calcification. Decalcification of these valves should be done mechanically and care must be exercised to avoid damage to the cusps. The calcium on the annulus should also be removed to make it more pliable. Long-term therapy with cholesterol-lowering agents may prevent recurrence of the aortic stenosis. Ultrasonic decalcification of aortic valve often causes scarring with retraction of the cusps and aortic insufficiency within a few months after surgery and it has been largely abandoned.27

Incompetent aortic valves due to dilation of one or more components of the aortic root or due to aortic cusp prolapse are amenable to aortic valve-conserving procedures. Since surgery in asymptomatic patients with aortic insufficiency is justifiable if the aortic valve can be repaired, it is important to identify these patients preoperatively. Transesophageal echocardiography is the best tool to study the aortic root and determine the mechanism of aortic insufficiency.28 The echocardiographer has to carefully interrogate each component of the aortic valve in multiple views to evaluate the number, quality, and morphology of the aortic cusps as well as to measure the diameters of the aortic annulus, aortic sinuses, sinotubular junction, and ascending aorta. In addition, the height of the cusps and the level of their coaptation should be measured. The most important information needed is related to the thickness, mobility, and general appearance of the aortic cusps.

Aortic insufficiency due to prolapse of one cusp, regardless of whether the valve has three or two cusps, is amenable to valve repair if the cusps are thin, pliable, and without calcification. Rugged and thickened free margins usually preclude a good repair. Cusp prolapse can also be caused by acute type A aortic dissection. Echocardiography not only diagnoses the dissection, but it also can aid the surgeon in planning the type of procedure in the aortic root.15

Dilation of the sinotubular junction in patients with ascending aortic aneurysm may cause aortic insufficiency by pulling the cusps apart, as shown in Figure 31-3. The aortic annulus is usually normal in these patients. Aortic valve repair is certainly feasible if transesophageal echocardiography shows the aortic cusps to be thin, mobile, and without calcification.



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FIGURE 31-3 Dilation of the sinotubular junction pulls the aortic cusps apart and causes aortic insufficiency. (Reproduced from David TE: Aortic valve repair for management of aortic insufficiency. Adv Card Surg 1999; 11:129, with permission from Mosby Inc.)

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Aneurysm of the aortic root is the most common indication for aortic valve-sparing operations. These patients may or may not have aortic insufficiency and, when insufficiency is present, the cusps may already be overstretched or contain stress fenestrations in their commissural areas and their free margins may be elongated. Patients with aortic root aneurysm and mild or no aortic insufficiency are better candidates for aortic valve-sparing than patients with more severe aortic insufficiency.


?? TECHNIQUES OF AORTIC VALVE REPAIR
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Cusp Perforation

Occasionally a cusp perforation is the sole reason for aortic insufficiency. The perforation may be iatrogenic, a sequelae of healed endocarditis, or the result of resection of a papillary fibroelastoma. A simple patch of fresh or glutaraldehyde-fixed autologous pericardium has been adequate to correct the problem.

Cusp Extension

Cusp extension has been used to repair rheumatic aortic insufficiency. Glutaraldehyde-fixed bovine or autologous pericardium has been used for this purpose.29

Cusp Prolapse

Isolated prolapse of a single cusp in adult patients with a tricuspid aortic valve is rare. Repair is accomplished by plication of the elongated free margin of the cusp (Fig. 31-4). The prolapsed cusp is usually thicker than normal and simple interrupted sutures with a 5-0 polypropylene are adequate. If the cusp is very thin, it may be safer to use mattressed sutures on pledgets of autologous pericardium. If the subcommissural triangles of the prolapsing cusps appear widened, they can be reduced with plicating sutures, leaving the knots on the outside of the left ventricular outflow tract. If the free margin is thinned and overstretched, it can be reinforced and shortened with a double layer of a 6-0 expanded polytetrafluoroethylene suture (Fig. 31-5).



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FIGURE 31-4 Repair of cusp prolapse.

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FIGURE 31-5 Reinforcement of the free margin of the aortic cusp with a single or double layer of a fine suture of expanded polytetrafluoroethylene.

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Bicuspid Aortic Valve

The most commonly performed aortic valve repair in adults is for congenitally bicuspid aortic valve with prolapse of one of the cusps. Although the anatomic arrangement of bicuspid aortic valves varies, most patients have an anterior cusp attached to the interventicular septum and a posterior cusp attached to the fibrous components of the left ventricular outflow tract. The anterior cusp often contains a raphe at approximately where the commissure between the right and left cusps would be. This cusp is usually the one that is elongated and prolapsed. As long as the posterior cusp is normal, repair is feasible and relatively simple. The raphe is excised and the free margin of the anterior cusp is shortened with plicating sutures (see Fig. 31-4). The lengths of the free margins of both cusps should be the similar and should coapt at the same level. This is determined by passing a suture through the arterial wall immediately above each of the two commissures, and then pulling them upward and gently apart.

Since most of these patients have some degree of annuloaortic ectasia, the two subcommissural triangles should also be plicated if possible to reduce the diameter of the aortic annulus and increase coaptation of the aortic cusps. This can be done with horizontal mattress sutures of 4-0 polypropylene with Teflon felt pledgets on the outside of the aortic root (see Fig. 31-4). The suture is initially passed from the outside to the inside of the aortic root 2 or 3 mm below the commissure and 1 mm above the aortic annulus into the aortic sinus, and then through the annulus of both cusps and outside of the aorta. The same suture is brought back 4 or 5 mm below that level on both sides of the annulus and the ends are tied together on the outside of the aorta. If the aortic root diameter exceeds 45 mm, the sinuses should be excised and an aortic valve-sparing operation performed.


?? AORTIC VALVE-SPARING OPERATIONS
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"Aortic valve-sparing operations" encompass various procedures used to preserve the aortic valve in patients with ascending aortic aneurysm and aortic insufficiency or aortic root aneurysm with or without aortic insufficiency.3033 The complexity of these operations varies with the pathologic process. Sometimes all that is needed is a simple reduction in the diameter of the sinotubular junction, which is often the case in older patients with ascending aortic aneurysm and normal aortic sinuses and aortic annulus. Other times more extensive procedures, which may include an aortic annuloplasty, replacement of the aortic sinuses, reimplantation of the coronary arteries, adjustment of the sinotubular junction, and correction of aortic cusp prolapse, are needed in young patients with aortic root aneurysm.

Ascending Aortic Aneurysm with Aortic Insufficiency

Dilation of the sinotubular junction displaces the commissures of the aortic valve outward and prevents the cusps from coapting during diastole (see Fig. 31-3). Most of these patients have normal or mildly stretched aortic cusps. If the aortic sinuses and annulus are not dilated, simple adjustment of the sinotubular junction restores aortic valve competence. This is accomplished by transecting the ascending aorta 5 mm above the commissures and pulling the three commissures upward and close to each other until the aortic cusps coapt. The three commissures form a triangle. The diameter of the circle that includes this triangle is the diameter of the graft that should be used to remodel the sinotubular junction. Because the aortic cusps frequently have different sizes, this triangle is not always equilateral and the commissures must be spaced according to the length of the free margin of each cusp. The diameter of the graft and the space between commissures are facilitated by sizing the diameter of the circle that contains all three commissures with a transparent valve sizer, such as the one for the Toronto SPV bioprosthesis (St Jude Medical, St Paul, MN). That particular sizer has three equidistant marks, and one can determine the space between the commissures by comparing to the distance between the marks. The tubular Dacron graft is sutured right at the level of the sinotubular junction with a continuous 4-0 polypropylene (Fig. 31-6). If after adjusting the sinotubular junction, one aortic cusp appears to prolapse, shortening of its free margin should be performed as described above. Valve competence can be checked at this time by injecting cardioplegia solution into the graft under pressure and observing the left ventricle for distension.



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FIGURE 31-6 Simple adjustment of the diameter of the sinotubular junction by a graft of appropriate diameter corrects aortic insufficiency in patients with ascending aortic aneurysm if the aortic cusps are normal. (Reproduced from David TE, Feindel CM, Bos J: Repair of the aortic valve in patients with aortic insufficiency and aortic root aneurysm. J Thorac Cardiovasc Surg 1995; 109:345, with permission from Mosby Inc.)

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Grafts smaller than 24 mm in diameter should be avoided in these patients because they may increase left ventricular afterload, particularly if long segments are used, such as with concomitant transverse arch replacement using the elephant trunk technique. If the estimated diameter of the sinotubular junction is less than 24 mm, a larger graft should be used, and the end that is anastomosed to the sinotubular junction reduced to the necessary diameter.

Aortic Root Aneurysm

Patients with aortic root aneurysm can have the aortic cusps preserved during surgery as long as they are reasonably normal. A common problem with these cusps is that stress fenestration may appear near the commissural areas. As long as the tissues are of good quality, it is possible to reinforce the free margins of the cusps and preserve the native valve (see Fig. 31-5). Although it is not always simple to determine intraoperatively if an aortic cusp is elongated or not, a fair estimation is obtained by pulling all three commissures vertically and approximating them to each other until the cusps coapt. The coaptation level should be well above the level of the aortic annulus, and if one cusp is elongated it can be identified. It is important to maintain the normal scalloped shape of the aortic annulus while the commissures are pulled upward.

Assessing dilation of the aortic annulus is even more difficult than assessing cusp prolapse. The aortic orifice is sealed by three aortic cusps, and the larger the cusps, the larger the aortic annulus. The geometric relationship between these two components of the aortic root is variable, but the diameter of the annulus must be smaller than the average lengths of the free margins of the aortic cusps and the radius of the annulus must be smaller than the height of the cusps. Using these two parameters, it is possible to estimate whether the annulus is dilated or not.

There are two general types of aortic valve-sparing operations for patients with aortic root aneurysms: remodeling of the aortic root and reimplantation of the aortic valve.31

REMODELING OF THE AORTIC ROOT

After the aorta is cross-clamped, the ascending aorta is transected and the aortic root is dissected circumferentially down to the level of the aortic annulus. All three aortic sinuses are excised, leaving approximately 4 to 6 mm of arterial wall attached all around the aortic annulus, as shown in Figure 31-7. If it the aortic annulus is not dilated, the three commissures are gently pulled vertically and approximated until the cusps coapt. The three commissures form a triangle and the diameter of the circle that contains that triangle is the diameter of the graft to be used for remodeling. Here again the sizers of the Toronto SPV are very useful to determine the diameter of the graft and also the distance between commissures, because they may not be equidistant. The spaces in between the commissures are marked in one of the ends of the graft, and the graft is tailored to create three neoaortic sinuses (Fig. 31-8A). The heights of these neosinuses should be approximately equal to the diameter of the graft. The three commissures are suspended in the graft (Fig. 31-9A), which is then sutured to the aortic annulus and remnants of the aortic wall with a continuous 4-0 polypropylene suture (Fig. 31-9B). After suturing the Dacron graft to the aortic annulus, the coronary arteries are reimplanted into their respective neoaortic sinuses. The three aortic cusps are then examined and their central coaptation evaluated. If one or more cusps appear to prolapse, the free margin should be shortened as described above. The coronary arteries are reimplanted into their sinuses. Aortic valve competence can be assessed by injecting cardioplegia under pressure into the graft and observing the left ventricle for distension. The graft is then anastomosed to the distal ascending aorta or transverse aortic arch graft depending on the extent of the aneurysm (Fig. 31-8B).



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FIGURE 31-7 (A) Remodeling of the aortic root for aortic root aneurysm. (B) The aortic sinuses are excised. (Reproduced from David TE: Remodeling of the aortic root with preservation of the native aortic valve. Op Tech Cardiac Thorac Surg 1996; 1:44, with permission from WB Saunders.)

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FIGURE 31-8 (A) A tubular Dacron graft is tailored to create three neo-aortic sinuses. (B) The complete repair. (Reproduced from David TE: Remodeling of the aortic root with preservation of the native aortic valve. Op Tech Cardiac Thorac Surg 1996; 1:44, with permission from WB Saunders.)

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FIGURE 31-9 (A) The three commissures are secured to the tailored end of the Dacron graft, and (B) the neo-aortic sinuses are sutured to the aortic annulus and remnants of the aortic sinuses. (Reproduced from David TE: Remodeling of the aortic root with preservation of the native aortic valve. Op Tech Cardiac Thorac Surg 1996; 1:44, with permission from WB Saunders.)

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If the patient has Marfan syndrome or annuloaortic ectasia, an aortic annuloplasty is necessary before the remodeling procedure is performed. A band of Dacron fabric is sutured on the outside of the ventricular outflow tract (Fig. 31-10). Multiple interrupted horizontal mattress sutures are placed through a single horizontal plane on the fibrous components of the left ventricular outflow tract and through the Dacron band. Most of the dilation of the aortic annulus occurs beneath the commissures of the noncoronary cusps. The aortic annulus should be reduced to a diameter approximately 20% less than the average lengths of the free margins of the aortic cusps and to a radius equal to approximately two thirds of the average heights of the aortic cusps. Clinical experience has demonstrated that these estimates of the diameter of the aortic annulus appear to correct the problem of annular dilation. Figure 31-11 illustrates the completed procedure.



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FIGURE 31-10 Aortic annuloplasty: a strip of Dacron fabric is secured to the fibrous components of the left ventricular outflow tract, immediately below the aortic annulus (A, B, C, and D). (Reproduced from David TE: Remodeling of the aortic root with preservation of the native aortic valve. Op Tech Cardiac Thorac Surg 1996; 1:44, with permission from WB Saunders.)

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FIGURE 31-11 Remodeling of the aortic root with aortic annuloplasty. (Reproduced from David TE: Remodeling of the aortic root with preservation of the native aortic valve. Op Tech Cardiac Thorac Surg 1996; 1:44, with permission from WB Saunders.)

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REIMPLANTATION OF THE AORTIC VALVE

This procedure can be performed in all patients with aortic root aneurysm, but it is particularly valuable in patients with annuloaortic ectasia and in those with acute type A aortic dissection. The three aortic sinuses are excised as described for the remodeling procedure. Multiple horizontal mattress sutures of 3-0 or 4-0 polyester are passed from the inside to the outside of the left ventricular outflow tract, immediately below the nadir of the aortic annulus, through a single horizontal plane along the fibrous portion of the outflow tract and along its scalloped shape in the interventricular septum (Fig. 31-12). If the fibrous portion is thin, sutures with small Teflon felt pledgets should be used. Next, the three commissures are pulled vertically and approximated to each other until the cusps coapt, in order to estimate the diameter of the sinotubular junction. A tubular graft with a diameter 3 or 4 mm larger than the estimated diameter of the sinotubular junction is selected, and three equidistant marks are placed in one of its ends to correspond approximately to each commissure. If one cusp is larger than the others, the distance between the three marks should reflect that. A small triangular wedge is trimmed off in the mark that corresponds to the commissure between the left and right cusps (Fig. 31-12). The polyester sutures passed through the left ventricular outflow tract are then passed through the graft from the inside to the outside, making an effort to space them correctly. One should remember that most of the dilation of the aortic annulus occurs beneath the commissures of the noncoronary cusp, and if any annular reduction is needed, those are the areas in which to do it. The sutures are tied on the outside of the graft. Care must be exercised not to purse-string this suture line. The graft is then cut in a length of approximately 6 to 7 cm and pulled upward gently, and the three commissures are pulled vertically and secured to the graft with transfixing 4-0 polypropylene sutures, but they are not tied. The appropriate position of the commissures is determined by observing the aortic cusps and the level of the free margins and where they coapt. If all three commissures are on a correct level, the remnants of the aortic wall are sutured to the graft using a full-thickness, transfixing continuous suture. The coronary arteries are reimplanted into their respective neosinuses (Fig. 31-13). The spaces between commissures immediately above their highest point is plicated to create neosinuses. For every 3 mm that are plicated, the diameter of the sinotubular junction is reduced by 1 mm. The coaptation level of the aortic cusps is checked again and valve competence can be assessed by injecting cardioplegia under pressure into the graft and observing the left ventricle for distension. The graft is then sutured to the distal ascending aorta or to the graft used to replace the transverse aortic arch.



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FIGURE 31-12 Reimplantation of the aortic valve. Multiple horizontal mattress sutures are placed in the left ventricular outflow tract, immediately below the aortic annulus and in a single horizontal plane along the fribrous components and following the scalloped shape of the annulus along the muscular attachments.

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FIGURE 31-13 Reimplantation of the aortic valve. The three commissures are resuspended inside the graft and the remnants of the aortic sinuses are secured to the Dacron graft. The coronary arteries are reimplanted.

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?? RESULTS OF AORTIC VALVE SURGERY
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Bicuspid Aortic Valve Repair

The largest published series on aortic valve repair for aortic insufficiency due to prolapse of bicuspid valve is from the Cleveland Clinic.34,35 Investigators from that institution reported on 94 patients with a mean age of 38 years. The freedom from reoperation was 84% at 7 years.35 The only factor predictive of reoperation was residual aortic insufficiency after the repair. There was no operative mortality in that series. Our experience with repair of bicuspid aortic valve is limited to 45 patients over the past decade. Six of them also required reconstruction of the aortic root. There were no operative or late deaths. During a mean follow-up of 3.7 years, one patient required aortic root replacement after cusp repair with remodeling of the aortic root.

Ascending Aortic Aneurysm with Aortic Insufficiency

We recently reported our experience with aortic valve-sparing operations in patients with ascending aortic aneurysm and aortic insufficiency.32 Replacement of the ascending aorta with adjustment of the sinotubular junction was performed in 68 patients.32 The mean age of 38 men and 30 women was 68 years. Thirteen patients had type A aortic dissection, 17 had coronary artery disease, 43 had transverse arch aneurysm, and 22 had mega-aorta syndrome. Six patients had bicuspid aortic valve. The aortic insufficiency was graded as moderate (3+) in 31 patients and severe (4+) in 37. There was one operative death. The survival at 5 years was 68% and the freedom from aortic valve replacement 97%. The freedom from moderate or severe aortic insufficiency at 5 years was 98%.

Aortic Root Aneurysm

We recently reported the results of aortic valve-sparing operations in 120 patients operated on from 1988 to 2000.33 Eleven patients had previous cardiac surgery: replacement of the ascending aorta in 10, and the Ross procedure in 1. Twenty-two patients had aortic dissection, 48 had Marfan syndrome, 17 had coronary artery disease, and 8 had severe mitral regurgitation. The mean diameter of the aortic root was 53 ? 8 mm and the aortic insufficiency was moderate or severe in 41% of the patients. Remodeling of the aortic root was used in 56 patients and reimplantation of the aortic valve in 64 patients. There were 2 operative deaths due to perioperative myocardial infarction. There was 1 operative failure early on in our experience, which required valve replacement. During a mean follow-up of 3 years, there were 5 late deaths (aortic dissection in 2 cases, sudden death in 1, and noncardiovascular causes in 2). The survival at 10 years was 88% ? 4%. The type of valve sparing had no effect on survival. The freedom from aortic valve replacement was 99% at 10 years. Late echocardiographic studies in 112 survivors showed no aortic insufficiency in 19, trace in 47, mild in 39, and moderate in 7. The freedom from moderate aortic insufficiency at 10 years was 83% ? 8%.

Yacoub et al,36 who used the remodeling procedure without an aortic annuloplasty in 158 patients, reported a freedom from aortic valve replacement of 89% at 10 years, and moderate aortic insufficiency in one third of the patients. It is conceivable that the development of aortic insufficiency and ultimately valve failure leading to reoperation in that series is due to the lack of annuloplasty in patients with annuloaortic ectasia. Actually, we presently use only the reimplantation technique in patients with Marfan syndrome or its forme fruste with dilated aortic annulus, including those with bicuspid aortic valve and aortic insufficiency, because we believe that the aortic annulus may dilate after remodeling of the aortic root.

Pethig et al reported their experience with 75 consecutive patients who had the reimplantation technique and were followed for at least one year.37 They found a correlation between the level of coaptation of the aortic cusps and the late development of aortic insufficiency, which was likely to occur if the coaptation level was below the level of the tubular graft. Our impression is that the level of coaptation after any type of valve-sparing procedure is a function of two factors: length of the free margins of the aortic cusps and size of the graft used for reconstruction. If the aortic cusps are elongated and/or if the graft is too small in diameter, the cusps will coapt at a low level within the reconstructed aortic root. Graeter et al found similar clinical and echocardiographic results after aortic root remodeling and reimplantation of the aortic valve at 5 years in patients with aortic root aneurysm.38

Finite element analysis of the aortic root by Grande-Allen et al suggested that placement of the aortic valve inside a cylindrical structure, such as used in the technique of reimplantation of the aortic valve, is associated with increased stress on the aortic cusps.2 In addition, since nature created the aortic root with sinuses of Valsalva, it may be prudent to create neoaortic sinuses during the reconstruction of the aortic root with preservation of the aortic cusps. Neoaortic sinuses are easily created during the remodeling procedure by tailoring the tubular Dacron graft in such a way that the perimeter of the scalloped end of the graft is longer than the perimeter of the aortic annulus. Neoaortic sinuses can also be created during reimplantation of the aortic valve by using a graft larger than needed, and then reducing it at the level of the aortic annulus and at the sinotubular junction as described earlier in the section on reimplantation of the aortic valve. De Paulis et al have developed a Dacron graft with neosinuses that is now commercially available (Gelweave Valsalva; Sulzer Vascutek, Renfrewshire, Scotland). Their initial experience with that prosthesis is satisfactory.39


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