**4. Indications**

Indications for surgical intervention upon aortic root and ascending aneurysms include the presence of symptoms, aortic size, rapid growth, and the degree of aortic insufficiency. Most patients with aortic aneurysms are asymptomatic. Symptomatic patients complain of chest pain, which is considered a sign of rapid growth, dissection or impending rupture(8). The guidelines for the treatment of asymptomatic patients are drawn from natural history studies which correlated serial aortic measurements and aortic complications (rupture or dissection). It has been demonstrated that the ascending aortic grows at a rate of 1mm/year, and by the time the diameter of ascending aneurysms reaches 6cm, patients have been subjected to a lifetime 34% risk of rupture or dissection (9).

In the largest reported series from the Yale Aortic Institute comparing growth rates and complications, 50% of patients with ascending aortic aneurysms suffered aortic rupture or dissection at a median aortic diameter of 5.9 cm (10). Furthermore, there is a "hinge" point in the data which identifies a significant increase in the probability of rupture or dissection when an aneurysm reaches a size of 6.0cm. Therefore, elective repair of aortic root or ascending aneurysms in trileaflet valves is recommended at a diameter of ≥ 5.5cm or a growth rate of ≥0.5cm/year (8,10). Patients with genetic disorders such as bicuspid aortic valve, Marfan syndrome, Ehlers-Danlos, Turner syndrome, or a familial history of aneurysm

Aortic Valve Sparing Operations 109

pathologic alterations in the cusps. The two most common alterations are elongation of the free margin or stress fenestrations near the commissures. Free margin elongation results in cusp prolapse, which can be corrected with a plication stitch in the center of cusp free margin at the nodule of Arantii. In the case of extensive stress fenestrations, the free margin is reinforced with a double layer 6-0 polytetrafluoroethylene suture. David and colleagues have shown that both of these adjunctive valve repair techniques are durable methods of

Restoring the normal diameter of the STJ is the key to achieving aortic valve competence in this procedure. There are two methods which are used to select the appropriate graft size which will define the neo-sinotubular junction. Once the aorta is transected, traction sutures are placed at the commissures and pulled up until the cusps achieve coaptation. The diameter of an imaginary circle which includes all three commissures is the ideal diameter of the neo-sinotubular junction (13). Next a transparent valve sizer (e.g. Medtronic Freestyle, Medtronic, Minneapolis, MN) is used to determine the annular diameter. The STJ and the annulus should be approximately the same diameter in order to recreate the normal aortic root geometry in this population. Furthermore, the location of the commissures should be marked on the graft and lined up accordingly during construction of the anastomosis in an effort to maintain normal root geometry (Figure 2). Once the graft has been sewn to the aorta, aortic valve competence can be tested by injecting cardioplegia into the graft under pressure. If the left ventricle remains decompressed and there is no distension, then the

David and colleagues reported their outcomes following ascending aortic replacement with reduction of the diameter of the sinotubular junction in 103 patients over a 15 year period. The mean age of these patients was 65 years and all patients had >3+ aortic insufficiency. 9% of patients had bicuspid aortic valves. The mean diameter of the neo-sinotubular junction following ascending replacement was 26mm, and leaflet repair was performed in 40 patients. There were two operative deaths, and 5 and 10 year survival was 80% and 54%. Freedom from moderate or severe aortic insufficiency at 5 and 10 years was 96% and 80%. Two patients in the entire series required reoperation for aortic valve replacement. One patient had severe aortic insufficiency and the other had infective endocarditis. The overall

El-Khoury's group also reported their experience with remodeling the STJ for the treatment of supracoronary aortic aneurysms and associated aortic insufficiency. In a smaller series of 55 patients with a mean age of 65, these authors reported an overall survival of 94% and 75% at 5 and 7 years follow-up. 31% of patients had bicuspid aortic valves. Adjunctive cusp repair procedures were performed in 51% of patients and 69% of patients underwent subcommissural annuloplasty. Freedom from recurrent >2+ aortic insufficiency 87% at 5 years, and none of their patients required subsequent aortic valve

The outcomes from these two series provide data that a durable aortic valve sparing operation can be accomplished by remodeling the sinotubular junction with a supracoronary graft and simple leaflet repair techniques in both bicuspid and trileaflet valves. Patient selection and careful examination of the aortic valve cusps with preoperative echocardiography and intraoperative examination is the key to achieving short and long-term success. If the leaflets are severely damaged, the aortic valve should

achieving long-term valve competence with this operation. (1).

10 year freedom from aortic valve replacement was 97% (1).

aortic valve is competent. (1).

replacement (14).

be replaced.

and dissection should undergo elective aortic replacement at a diameter of <5cm depending upon the specific disease (8). These patients have a higher risk of rupture or dissection at smaller aortic diameters. It should be noted that the diameter for aortic intervention can be adjusted for body size based upon published nomograms correlating the aortic rupture/dissection risk to aortic diameter and body surface area (9).

In other situations, the primary indication for surgical intervention is aortic insufficiency and not aneurysmal disease. Current recommendations for aortic valve repair or replacement in the setting of chronic severe aortic insufficiency include: (1) symptoms of congestive heart failure, (2) left ventricular dysfunction with an ejection fraction ≤ 50% at rest, (3) concomitant cardiac or aortic surgery, (4) LV end-diastolic dimension of > 75mm, (5) LV end-systolic dimension of > 55mm and (6) declining exercise tolerance (11). When operating for a valvular indication or aortic dissection, concomitant aortic root or ascending replacement is recommended at aortic diameters ≥4.5cm. In the setting of severe aortic insufficiency and aortic aneurysmal disease, aggressive operative intervention earlier rather than later may enable AVS operation to be performed. Longstanding, severe aortic insufficiency can damage the cusps, causing stress fenestrations or thickening of the free margin which may render the cusps unrepairable and mandate valve replacement.

In addition to the indications listed above, the surgeon must exhibit judgment in patients selected to receive a valve sparing operation. The patient's age and comorbid status must be taken into consideration. Given the excellent durability of bioprosthetic valves, patients with a life expectancy < 15 years should probably undergo aortic valve replacement. The aortic cusps must be carefully inspection both preoperatively on the transesophageal echocardiogram and at the time of surgery once the aorta is transected. Significant calcification of the annulus and cusps are generally considered prohibitive of an AVS operation. Severe free margin thickening has also been demonstrated to limit long term valve durability following AVS operations (7, 12). However stress fenestrations and free margin elongation are not contraindications to a valve sparing procedure, and valve repair techniques are often added to an AVS operation. Due to the extensive reconstruction involved in valve-sparing root replacement, myocardial protection is paramount, as the possibility of a second period of myocardial ischemia exists if the valve repair fails. All of these factors must be considered prior to proceeding with a valve-sparing procedure.

#### **5. Ascending aortic replacement with remodeling of the sinotubular junction**

Aortic insufficiency can occur in the setting of either isolated ascending aortic aneurysms or due to aortic root aneurysms. Isolated ascending aortic aneurysms cause aortic insufficiency due to dilation of the STJ which pulls the commissures apart and prevents valve coaptation during diastole (2). If the remainder of the aortic root components are normal, then a reduction of the STJ diameter will restore valve competence. Typically these patients are older and have a large ascending aortic aneurysm and aortic insufficiency. The preoperative echocardiogram will demonstrate loss of STJ definition, minimal dilation of the sinuses and central aortic insufficiency due to lack of cusp coaptation.

During the operation, the aorta is transected approximately 5mm distal to the STJ and the cusps are inspected. Often the cusps are small, there is minimal annular dilatation and the ridge of the STJ is unrecognizable. If the aortic insufficiency has been chronic, there may be

and dissection should undergo elective aortic replacement at a diameter of <5cm depending upon the specific disease (8). These patients have a higher risk of rupture or dissection at smaller aortic diameters. It should be noted that the diameter for aortic intervention can be adjusted for body size based upon published nomograms correlating the aortic

In other situations, the primary indication for surgical intervention is aortic insufficiency and not aneurysmal disease. Current recommendations for aortic valve repair or replacement in the setting of chronic severe aortic insufficiency include: (1) symptoms of congestive heart failure, (2) left ventricular dysfunction with an ejection fraction ≤ 50% at rest, (3) concomitant cardiac or aortic surgery, (4) LV end-diastolic dimension of > 75mm, (5) LV end-systolic dimension of > 55mm and (6) declining exercise tolerance (11). When operating for a valvular indication or aortic dissection, concomitant aortic root or ascending replacement is recommended at aortic diameters ≥4.5cm. In the setting of severe aortic insufficiency and aortic aneurysmal disease, aggressive operative intervention earlier rather than later may enable AVS operation to be performed. Longstanding, severe aortic insufficiency can damage the cusps, causing stress fenestrations or thickening of the free margin which may render the cusps unrepairable and mandate

In addition to the indications listed above, the surgeon must exhibit judgment in patients selected to receive a valve sparing operation. The patient's age and comorbid status must be taken into consideration. Given the excellent durability of bioprosthetic valves, patients with a life expectancy < 15 years should probably undergo aortic valve replacement. The aortic cusps must be carefully inspection both preoperatively on the transesophageal echocardiogram and at the time of surgery once the aorta is transected. Significant calcification of the annulus and cusps are generally considered prohibitive of an AVS operation. Severe free margin thickening has also been demonstrated to limit long term valve durability following AVS operations (7, 12). However stress fenestrations and free margin elongation are not contraindications to a valve sparing procedure, and valve repair techniques are often added to an AVS operation. Due to the extensive reconstruction involved in valve-sparing root replacement, myocardial protection is paramount, as the possibility of a second period of myocardial ischemia exists if the valve repair fails. All of

these factors must be considered prior to proceeding with a valve-sparing procedure.

central aortic insufficiency due to lack of cusp coaptation.

**5. Ascending aortic replacement with remodeling of the sinotubular junction**  Aortic insufficiency can occur in the setting of either isolated ascending aortic aneurysms or due to aortic root aneurysms. Isolated ascending aortic aneurysms cause aortic insufficiency due to dilation of the STJ which pulls the commissures apart and prevents valve coaptation during diastole (2). If the remainder of the aortic root components are normal, then a reduction of the STJ diameter will restore valve competence. Typically these patients are older and have a large ascending aortic aneurysm and aortic insufficiency. The preoperative echocardiogram will demonstrate loss of STJ definition, minimal dilation of the sinuses and

During the operation, the aorta is transected approximately 5mm distal to the STJ and the cusps are inspected. Often the cusps are small, there is minimal annular dilatation and the ridge of the STJ is unrecognizable. If the aortic insufficiency has been chronic, there may be

rupture/dissection risk to aortic diameter and body surface area (9).

valve replacement.

pathologic alterations in the cusps. The two most common alterations are elongation of the free margin or stress fenestrations near the commissures. Free margin elongation results in cusp prolapse, which can be corrected with a plication stitch in the center of cusp free margin at the nodule of Arantii. In the case of extensive stress fenestrations, the free margin is reinforced with a double layer 6-0 polytetrafluoroethylene suture. David and colleagues have shown that both of these adjunctive valve repair techniques are durable methods of achieving long-term valve competence with this operation. (1).

Restoring the normal diameter of the STJ is the key to achieving aortic valve competence in this procedure. There are two methods which are used to select the appropriate graft size which will define the neo-sinotubular junction. Once the aorta is transected, traction sutures are placed at the commissures and pulled up until the cusps achieve coaptation. The diameter of an imaginary circle which includes all three commissures is the ideal diameter of the neo-sinotubular junction (13). Next a transparent valve sizer (e.g. Medtronic Freestyle, Medtronic, Minneapolis, MN) is used to determine the annular diameter. The STJ and the annulus should be approximately the same diameter in order to recreate the normal aortic root geometry in this population. Furthermore, the location of the commissures should be marked on the graft and lined up accordingly during construction of the anastomosis in an effort to maintain normal root geometry (Figure 2). Once the graft has been sewn to the aorta, aortic valve competence can be tested by injecting cardioplegia into the graft under pressure. If the left ventricle remains decompressed and there is no distension, then the aortic valve is competent. (1).

David and colleagues reported their outcomes following ascending aortic replacement with reduction of the diameter of the sinotubular junction in 103 patients over a 15 year period. The mean age of these patients was 65 years and all patients had >3+ aortic insufficiency. 9% of patients had bicuspid aortic valves. The mean diameter of the neo-sinotubular junction following ascending replacement was 26mm, and leaflet repair was performed in 40 patients. There were two operative deaths, and 5 and 10 year survival was 80% and 54%. Freedom from moderate or severe aortic insufficiency at 5 and 10 years was 96% and 80%. Two patients in the entire series required reoperation for aortic valve replacement. One patient had severe aortic insufficiency and the other had infective endocarditis. The overall 10 year freedom from aortic valve replacement was 97% (1).

El-Khoury's group also reported their experience with remodeling the STJ for the treatment of supracoronary aortic aneurysms and associated aortic insufficiency. In a smaller series of 55 patients with a mean age of 65, these authors reported an overall survival of 94% and 75% at 5 and 7 years follow-up. 31% of patients had bicuspid aortic valves. Adjunctive cusp repair procedures were performed in 51% of patients and 69% of patients underwent subcommissural annuloplasty. Freedom from recurrent >2+ aortic insufficiency 87% at 5 years, and none of their patients required subsequent aortic valve replacement (14).

The outcomes from these two series provide data that a durable aortic valve sparing operation can be accomplished by remodeling the sinotubular junction with a supracoronary graft and simple leaflet repair techniques in both bicuspid and trileaflet valves. Patient selection and careful examination of the aortic valve cusps with preoperative echocardiography and intraoperative examination is the key to achieving short and long-term success. If the leaflets are severely damaged, the aortic valve should be replaced.

Aortic Valve Sparing Operations 111

Fig. 3. Aortic Root Remodeling. From David TE. Aortic Valve Repair and Aortic Valve-Sparing Operations. In: Cohn LH, ed. *Cardiac Surgery in the Adult.* New York, NY: McGraw

"unsalvageable" despite leaflet repair techniques, then the valve is excised and a conventional Bentall root replacement is performed (16). If the cusps are normal, then the aortic root is dissected out from the surrounding cardiac chambers all the way down to the aortic annulus. The abnormal aneurysmal sinus tissue is excised, leaving a 5mm remnant of aortic wall above the annulus. Traction sutures are placed at the top of each commissure. Additionally, the orifice and proximal portions of the left and right coronary arteries are dissected away form the surrounding structures leaving 5mm circumferentially of sinus tissue to form "coronary buttons". Next, a Dacron graft is sized in a manner similar to the STJ remodeling procedure previously described. The traction sutures above each commissure are pulled up until the cusps achieve coaptation. The graft diameter is the diameter of an imaginary circle which includes all three commissures. A transparent valve sizer (e.g. Medtronic Freestyle) can be used to help determine the optimal graft diameter. The positions of the commissures are marked on the graft. The graft is then tailored with

Hill:935-948, 2008

Fig. 2. Sinotubular Junction Remodeling. From David TE. Aortic Valve Repair and Aortic Valve-Sparing Operations. In: Cohn LH, ed. *Cardiac Surgery in the Adult.* New York, NY: McGraw Hill:935-948, 2008
