**6. Valve sparing aortic root replacement- remodeling technique**

Yacoub developed the aortic root remodeling procedure to treat patients with aortic root aneurysms, aortic insufficiency and normal aortic valve cusps. In this population of patients, the pathology is confined to the aortic wall. He reported the first series of valve sparing root replacements for the treatment of 10 patients with aortic root aneurysms and aortic insufficiency in 1993 (15). In this series he described the technique of aortic root remodeling by replacing all diseased aortic root tissue with a tailored Dacron graft. One end of the graft was fashioned to produce three individual tongues which became the neo-aortic sinus segments of the remodeled root (Figure 3). The operative technique is described below.

After initiating cardiopulmonary bypass, the aorta is transected and a careful examination of the aortic valve cusps is performed. If abnormal cusps are discovered and found to be

**6. Valve sparing aortic root replacement- remodeling technique** 

McGraw Hill:935-948, 2008

described below.

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:

Yacoub developed the aortic root remodeling procedure to treat patients with aortic root aneurysms, aortic insufficiency and normal aortic valve cusps. In this population of patients, the pathology is confined to the aortic wall. He reported the first series of valve sparing root replacements for the treatment of 10 patients with aortic root aneurysms and aortic insufficiency in 1993 (15). In this series he described the technique of aortic root remodeling by replacing all diseased aortic root tissue with a tailored Dacron graft. One end of the graft was fashioned to produce three individual tongues which became the neo-aortic sinus segments of the remodeled root (Figure 3). The operative technique is

After initiating cardiopulmonary bypass, the aorta is transected and a careful examination of the aortic valve cusps is performed. If abnormal cusps are discovered and found to be

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 Hill:935-948, 2008

"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

Aortic Valve Sparing Operations 113

aneurysm who had elected to get an aortic valve homograft so that she could eventually have children. Instead, David reimplanted her native valve into a cylindrical Dacron tube graft (22). Since the original operation, this pioneering procedure has undergone several modifications and has been adopted by surgeons worldwide as their primary AVS operation. The technical aspects of the most recent iteration of the David V reimplantation

Once the decision is made to proceed with valve-sparing root replacement, the root is circumferentially dissected down to the nadir of the aortic annulus. All abnormal sinus tissue is excised, leaving a 5mm rim of aortic tissue above the annulus. Coronary buttons are also fashioned, and 4-0 pledgeted polypropolene sutures are placed from inside to out just

Fig. 4. Aortic Root Remodeling with Annuloplasty. From David TE. Remodeling of the Aortic Root and Preservation of the Native Aortic Valve. *Operative Techniques in Cardiac &* 

procedure are described in the following paragraphs.

above the top of each commissure.

*Thoracic Surgery.* 1996; 1:44-56

three longitudinal cuts at the positions of the commissures with the ends rounded to create neo-aortic sinuses which are the width of the intercommissural distance. It is important to make the heights of the three neo-sinuses (two in the case of bicuspid valve) approximately the same size as the diameter of the graft to properly recreate normal aortic root geometry. Once the neo-sinus segments of the root graft are created, the commissural posts are sutured outside the graft above the neo-sinus (Figure 3). Then the remnant aortic wall tissue above the annulus is sutured to the graft with a running stitch. Once this is complete, holes are made inside the root graft with an ophthalmic cautery and the coronary buttons are reimplanted. At this point the leaflets are inspected again, and any leaflet repairs are performed at this time. The ideal level of coaptation is 5-6mm above the level of the nadir of the aortic annulus, and the optimal length of the coaptation zone is 4mm. Before proceeding with the remainder of the planned procedure, valve competency is re-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. (2, 17)

Yacoub reported the long term results of his remodeling procedure in 158 patients over an 18 year period. All patients had aortic root aneurysms, and 31% were performed in the setting of acute Type A aortic dissection. 43% of these patients had Marfan syndrome. 49% of patients had preoperative moderate aortic insufficiency and 18% had severe aortic insufficiency. The elective aneurysm group had a 1 and 10 year survival of 97% and 82%, while the acute dissection cohort had survival rates of 73% and 53%. Post-operative echocardiography revealed that 64% of patients had trivial or no aortic insufficiency, 33% had mild to moderate aortic insufficiency, and only 3% had severe aortic insufficiency. Freedom from reoperation was 99% and 89% at 1 and 10 years (18).

David modified Yacoub's remodeling technique for patients with annuloaortic ectasia or Marfan syndrome by adding an annuloplasty to the fibrous portion of the aortic annulus in an attempt to prevent future annular dilatation (19). This was accomplished by passing multiple horizontal sutures from inside to out on the fibrous aspect of the left ventricular outflow tract underneath the annulus. These sutures are then passed through a narrow strip of Dacron or Teflon felt and tied down to reduce the diameter of the aortic annulus (Figure 4). David recently reported his 12 year follow-up data from 61 patients who underwent his modified remodeling procedure. 42% of these patients had Marfan syndrome and 12% were performed in the setting of acute Type A dissection. 34% of patients had preoperative moderate aortic insufficiency, and 21% had severe aortic insufficiency. There was 1 operative death and survival rates were 97% and 83% at 1 and 12 years. At 12 years, freedom from moderate or severe aortic insufficiency was 83%, and freedom from reoperation upon the aortic valve was 90% (17). Other groups have also reported durable long-term valve function following root remodeling including patients with bicuspid valves (20, 21).

The root remodeling has been adopted by many surgeons and has produced excellent long term results with durable aortic valve function. However, due to its lack of an annuloplasty, many surgeons prefer the reimplantation technique, especially in patients with annular dilatation or connective tissue disorders.

#### **7. Valve sparing aortic root replacement-reimplantation technique**

In 1989, David performed the first valve sparing root replacement using the reimplantation technique. The patient was a young woman with Marfan syndrome and a 5.4cm aortic root

three longitudinal cuts at the positions of the commissures with the ends rounded to create neo-aortic sinuses which are the width of the intercommissural distance. It is important to make the heights of the three neo-sinuses (two in the case of bicuspid valve) approximately the same size as the diameter of the graft to properly recreate normal aortic root geometry. Once the neo-sinus segments of the root graft are created, the commissural posts are sutured outside the graft above the neo-sinus (Figure 3). Then the remnant aortic wall tissue above the annulus is sutured to the graft with a running stitch. Once this is complete, holes are made inside the root graft with an ophthalmic cautery and the coronary buttons are reimplanted. At this point the leaflets are inspected again, and any leaflet repairs are performed at this time. The ideal level of coaptation is 5-6mm above the level of the nadir of the aortic annulus, and the optimal length of the coaptation zone is 4mm. Before proceeding with the remainder of the planned procedure, valve competency is re-tested by injecting cardioplegia into the graft under pressure. If the left ventricle remains decompressed and

Yacoub reported the long term results of his remodeling procedure in 158 patients over an 18 year period. All patients had aortic root aneurysms, and 31% were performed in the setting of acute Type A aortic dissection. 43% of these patients had Marfan syndrome. 49% of patients had preoperative moderate aortic insufficiency and 18% had severe aortic insufficiency. The elective aneurysm group had a 1 and 10 year survival of 97% and 82%, while the acute dissection cohort had survival rates of 73% and 53%. Post-operative echocardiography revealed that 64% of patients had trivial or no aortic insufficiency, 33% had mild to moderate aortic insufficiency, and only 3% had severe aortic insufficiency.

David modified Yacoub's remodeling technique for patients with annuloaortic ectasia or Marfan syndrome by adding an annuloplasty to the fibrous portion of the aortic annulus in an attempt to prevent future annular dilatation (19). This was accomplished by passing multiple horizontal sutures from inside to out on the fibrous aspect of the left ventricular outflow tract underneath the annulus. These sutures are then passed through a narrow strip of Dacron or Teflon felt and tied down to reduce the diameter of the aortic annulus (Figure 4). David recently reported his 12 year follow-up data from 61 patients who underwent his modified remodeling procedure. 42% of these patients had Marfan syndrome and 12% were performed in the setting of acute Type A dissection. 34% of patients had preoperative moderate aortic insufficiency, and 21% had severe aortic insufficiency. There was 1 operative death and survival rates were 97% and 83% at 1 and 12 years. At 12 years, freedom from moderate or severe aortic insufficiency was 83%, and freedom from reoperation upon the aortic valve was 90% (17). Other groups have also reported durable long-term valve

function following root remodeling including patients with bicuspid valves (20, 21).

**7. Valve sparing aortic root replacement-reimplantation technique** 

The root remodeling has been adopted by many surgeons and has produced excellent long term results with durable aortic valve function. However, due to its lack of an annuloplasty, many surgeons prefer the reimplantation technique, especially in patients with annular

In 1989, David performed the first valve sparing root replacement using the reimplantation technique. The patient was a young woman with Marfan syndrome and a 5.4cm aortic root

there is no distension, then the aortic valve is competent. (2, 17)

Freedom from reoperation was 99% and 89% at 1 and 10 years (18).

dilatation or connective tissue disorders.

aneurysm who had elected to get an aortic valve homograft so that she could eventually have children. Instead, David reimplanted her native valve into a cylindrical Dacron tube graft (22). Since the original operation, this pioneering procedure has undergone several modifications and has been adopted by surgeons worldwide as their primary AVS operation. The technical aspects of the most recent iteration of the David V reimplantation procedure are described in the following paragraphs.

Once the decision is made to proceed with valve-sparing root replacement, the root is circumferentially dissected down to the nadir of the aortic annulus. All abnormal sinus tissue is excised, leaving a 5mm rim of aortic tissue above the annulus. Coronary buttons are also fashioned, and 4-0 pledgeted polypropolene sutures are placed from inside to out just above the top of each commissure.

Fig. 4. Aortic Root Remodeling with Annuloplasty. From David TE. Remodeling of the Aortic Root and Preservation of the Native Aortic Valve. *Operative Techniques in Cardiac & Thoracic Surgery.* 1996; 1:44-56

Aortic Valve Sparing Operations 115

Multiple (9-12) 2-0 or 3-0 horizontal pledgeted mattress stitches are placed circumferentially from inside to out of the left ventricular outflow tract at the level of 2mm below the nadir of the annulus in a horizontal plane. These stitches go through the fibrous portion of the outflow tract and the muscular interventricular septum and are passed through the tailored end of the Dacron graft. If the aortic annulus is not dilated, these sutures are spaced symmetrically. In the case of annular dilatation, the sutures which are placed in the area of the subcommissural triangles of the non-coronary cusp should be placed closer together, as this is where annular dilatation occurs. Next the commissural stitches are brought through the inside of the graft and the graft is seated around the outside of the annulus. The sutures are tied to secure the graft to the outside of the annulus, but not too tightly, which would

The graft is cut to about 5-7 cm in height and the commissural sutures are pulled up vertically and the cusps are assessed for the position of optimal coaptation. Once the ideal position of each commissure is recognized, the sutures on each commissure are passed through the root graft. This resuspends the valve inside the graft, and the cusps and commissures are inspected carefully for proper alignment and coaptation. Optimal position results in coaptation of all cusps at the same level approximately 5-6mm above the nadir of the annulus and a 4mm coaptation zone. The sutures of the commissures are tied outside the graft. Next, the annulus is secured to the graft by a 4-0 running polypropylene stitch by passing the needle from inside to out on the graft 1mm above the annulus and outside to in on the graft. Multiple sutures are used to secure the scalloped aortic annulus to the graft. Once this is complete, holes are made in the appropriate positions and the coronary artery buttons are reimplanted. Pleating stitches are again placed between each commissure to create bulges in the graft which form the neo-sinuses. Each 3mm of plication reduces the diameter of the neo-sinotubular junction by 1mm. Pressurized cardioplegia is injected into the graft to test for valve competence and hemostasis. Any necessary cusp repair procedures are performed at this time. When valve

In 2010, David reported his long-term results of 228 patients who underwent valve-sparing root replacement with the reimplantation technique. This series represented his entire experience with the reimplantation procedure including modifications of his own technique. 34% of patients had Marfan syndrome, 10% had bicuspid valves, and 8% of patients were operated on in the setting of acute Type A dissection. 24% of patients had moderate aortic insufficiency preoperatively, and 27% had severe aortic insufficiency. There were 4 operative deaths and survival at 1 and 12 years was 97% and 83%. 6 patients developed postoperative moderate aortic insufficiency and 2 patients developed severe aortic insufficiency. Freedom from moderate or severe aortic insufficiency at 4 and 12 years was 98% and 91 %. Two patients required reoperation on the aortic valve resulting in a freedom

The importance and reproducibility of David's reimplantation technique is underscored by its adoption by surgeons worldwide who perform reimplantation procedures. In 2005 the Hannover group reported their 11 year experience with the reimplantation technique in 284 patients. 19% of patients had Marfan syndrome, 6% had bicuspid aortic valves and 19% of patients were operated on in the setting of acute Type A dissection. Elective operative mortality was 1.3%, and overall operative mortality was 3.1%. At 10 years follow-up, survival was 80%, and freedom from reoperation due to aortic valve dysfunction was 87%. In their analysis, the authors discovered that Marfan syndrome was an independent risk

competence is satisfactory, the graft is sutured to the distal aorta.

from reoperation at 4 and 12 years of 99% and 97% (17).

factor for requiring reoperation on the aortic valve (25).

pursestring the graft (2).

In the reimplantation procedure, correct graft size selection is paramount to achieving a successful result. In the David V procedure, the diameter of the graft = 2(2/3 average cusp height) + 8mm. This is a slight modification of the original David-Feindel formula, as it enlarges the graft by 2mm to create neo-sinus segments (23,24) A ruler is used to measure the height of the cusp from the hinge point at the nadir of the annulus to the free margin edge at the nodule of Arantius. This formula is based upon the anatomic relationships of the normal human aortic root. Cusp height (as opposed to the annulus, STJ, or sinus) is used as the measured distance upon which graft size is based because it is the only relatively fixed measurement in the aortic root complex. In large series, most grafts range from 30-36mm in diameter (24).

Sizing the graft in this fashion allows for a graft larger than the ideal STJ and annulus, which can be plicated down at the top and bottom to create neo-sinus segments. A transparent valve sizer is used to measure the annulus. If annular dilatation is present, a valve sizer smaller than the anuulus is selected and the graft sizer is placed through the bottom of the graft. A series of interrupted pleating stitches approximately 4mm above the end of the graft plicates the annular end of the graft down to the diameter of the valve sizer. The positions of the commissures are also marked on the graft, and a small triangle is cut out at the position of the left/right commissure.

Fig. 5. David V Reimplantation Procedure. 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

In the reimplantation procedure, correct graft size selection is paramount to achieving a successful result. In the David V procedure, the diameter of the graft = 2(2/3 average cusp height) + 8mm. This is a slight modification of the original David-Feindel formula, as it enlarges the graft by 2mm to create neo-sinus segments (23,24) A ruler is used to measure the height of the cusp from the hinge point at the nadir of the annulus to the free margin edge at the nodule of Arantius. This formula is based upon the anatomic relationships of the normal human aortic root. Cusp height (as opposed to the annulus, STJ, or sinus) is used as the measured distance upon which graft size is based because it is the only relatively fixed measurement in the aortic root complex. In large series, most grafts range from 30-36mm in

Sizing the graft in this fashion allows for a graft larger than the ideal STJ and annulus, which can be plicated down at the top and bottom to create neo-sinus segments. A transparent valve sizer is used to measure the annulus. If annular dilatation is present, a valve sizer smaller than the anuulus is selected and the graft sizer is placed through the bottom of the graft. A series of interrupted pleating stitches approximately 4mm above the end of the graft plicates the annular end of the graft down to the diameter of the valve sizer. The positions of the commissures are also marked on the graft, and a small triangle is cut out at the position

Fig. 5. David V Reimplantation Procedure. From David TE. Aortic Valve Repair and Aortic Valve-Sparing Operations. In: Cohn LH, ed. *Cardiac Surgery in the Adult.* New York, NY:

diameter (24).

of the left/right commissure.

McGraw Hill:935-948, 2008

Multiple (9-12) 2-0 or 3-0 horizontal pledgeted mattress stitches are placed circumferentially from inside to out of the left ventricular outflow tract at the level of 2mm below the nadir of the annulus in a horizontal plane. These stitches go through the fibrous portion of the outflow tract and the muscular interventricular septum and are passed through the tailored end of the Dacron graft. If the aortic annulus is not dilated, these sutures are spaced symmetrically. In the case of annular dilatation, the sutures which are placed in the area of the subcommissural triangles of the non-coronary cusp should be placed closer together, as this is where annular dilatation occurs. Next the commissural stitches are brought through the inside of the graft and the graft is seated around the outside of the annulus. The sutures are tied to secure the graft to the outside of the annulus, but not too tightly, which would pursestring the graft (2).

The graft is cut to about 5-7 cm in height and the commissural sutures are pulled up vertically and the cusps are assessed for the position of optimal coaptation. Once the ideal position of each commissure is recognized, the sutures on each commissure are passed through the root graft. This resuspends the valve inside the graft, and the cusps and commissures are inspected carefully for proper alignment and coaptation. Optimal position results in coaptation of all cusps at the same level approximately 5-6mm above the nadir of the annulus and a 4mm coaptation zone. The sutures of the commissures are tied outside the graft. Next, the annulus is secured to the graft by a 4-0 running polypropylene stitch by passing the needle from inside to out on the graft 1mm above the annulus and outside to in on the graft. Multiple sutures are used to secure the scalloped aortic annulus to the graft. Once this is complete, holes are made in the appropriate positions and the coronary artery buttons are reimplanted. Pleating stitches are again placed between each commissure to create bulges in the graft which form the neo-sinuses. Each 3mm of plication reduces the diameter of the neo-sinotubular junction by 1mm. Pressurized cardioplegia is injected into the graft to test for valve competence and hemostasis. Any necessary cusp repair procedures are performed at this time. When valve competence is satisfactory, the graft is sutured to the distal aorta.

In 2010, David reported his long-term results of 228 patients who underwent valve-sparing root replacement with the reimplantation technique. This series represented his entire experience with the reimplantation procedure including modifications of his own technique. 34% of patients had Marfan syndrome, 10% had bicuspid valves, and 8% of patients were operated on in the setting of acute Type A dissection. 24% of patients had moderate aortic insufficiency preoperatively, and 27% had severe aortic insufficiency. There were 4 operative deaths and survival at 1 and 12 years was 97% and 83%. 6 patients developed postoperative moderate aortic insufficiency and 2 patients developed severe aortic insufficiency. Freedom from moderate or severe aortic insufficiency at 4 and 12 years was 98% and 91 %. Two patients required reoperation on the aortic valve resulting in a freedom from reoperation at 4 and 12 years of 99% and 97% (17).

The importance and reproducibility of David's reimplantation technique is underscored by its adoption by surgeons worldwide who perform reimplantation procedures. In 2005 the Hannover group reported their 11 year experience with the reimplantation technique in 284 patients. 19% of patients had Marfan syndrome, 6% had bicuspid aortic valves and 19% of patients were operated on in the setting of acute Type A dissection. Elective operative mortality was 1.3%, and overall operative mortality was 3.1%. At 10 years follow-up, survival was 80%, and freedom from reoperation due to aortic valve dysfunction was 87%. In their analysis, the authors discovered that Marfan syndrome was an independent risk factor for requiring reoperation on the aortic valve (25).

in 1998.

32, 33, 34).

**9. Conclusions** 

deterioration.

**10. References** 

2007;133:414-8.

Aortic Valve Sparing Operations 117

that the reason for the progression of dilatation in the remodeling cohort, even in the presence of an annuloplasty is that either the small amount of remnant connective tissue between the annuloplasty line and the remodeling suture line dilated, or the annuloplasty sutures cut through the abnormal fibrous tissue of the LVOT (28). David abandoned the use of the remodeling procedure in favor of reimplantation for patients with Marfan syndrome

It has been recognized by multiple surgeons who perform both procedures that the remodeling procedure is a simpler, faster procedure as it requires one less suture line and requires less dissection and mobilization of the root (29, 30). The David V is a considerably more complex procedure, but it allows the surgeon the flexibility to adjust all of the components of the aortic root complex in order to achieve normal physiologic function. Despite its complexity, it has gained worldwide adoption and is the procedure of choice by the majority of surgeons who perform valve-sparing root replacements. Furthermore, many surgeons have published modifications of the David V technique with excellent results (31,

Both the remodeling and the reimplantation procedures have demonstrated excellent longterm aortic valve durability. The two operations should be viewed as complementary rather than competing procedures. Most surgeons recommend that patients with annuloaortic ectasia, Marfan syndrome and other connective tissue disorders are best served by a reimplantation procedure. The remodeling procedure should be reserved for older patients

The treatment of patients with aortic root and ascending aortic aneurysms has been evolving over the past three decades. The majority of patients are still currently receiving Bentall procedure with a mechanical or bioprosthetic valved conduit. However, the number of surgeons performing AVS operations is increasing, and the indications are expanding. More surgeons are beginning to perform these procedures on patients with bicuspid valves, severe aortic insufficiency, and in the setting of acute Type A dissection. Again, patient selection and cusp examination are paramount to achieving success, but the addition of cusp repair techniques to the AVS operation has enabled an increasing number of patients to retain their native valves. The long-term data has proven that these operations can be performed with low morbidity and mortality, and provide durable aortic valve function. When feasible, AVS operations are the optimal treatment for patients with aortic disease and normal leaflets, as they avoid the burden of lifelong anticoagulation and significantly reduce their risk of endocarditis or requiring a subsequent operation for structural valve

[1] David TE, Feindel CM, Armstrong S, Maganti M. Replacement of the ascending aorta

with reduction of the diameter of the sinotubular junction to treat aortic insufficiency in patients with ascending aortic aneurysm. *J Thorac Cardiovasc Surg.* 

with a normal aortic annulus ((≤25mm woman, ≤27mm man) (17, 34)

The contribution of the shape of the sinus segments to minimizing stress and strain on the cusps and has led to the creation of the Valsalva graft, a graft with premade spherical sinus segments (6) (Vascutek, Renfrewshire, Scotland). In 2010, DePaulis reported a multi-center study from 8 Italian surgeons reporting the long-term results of performing the reimplantation technique with the Valsalva graft in 278 patients. 15% of patients had Marfan syndrome, 11% had bicuspid aortic valves, and 5% of patients underwent valve-sparing procedures in the setting of an acute Type A dissection. 49% of patients had preoperative moderate-severe aortic insufficiency. Operative mortality was 1.8%. At 10 year follow-up, survival was 95% and freedom from significant aortic insufficiency was 88%. 17 patients underwent subsequent AVR for a 10 year freedom from reoperation of on the aortic valve of 91%. The results of this multi-center study highlights the reproducibility of the David V procedure. Although many surgeons prefer to tailor their own graft, the use of a standardized, commercially available graft which has proven excellent long-term valve durability has both simplified and standardized the procedure (26).

#### **8. Remodeling vs reimplantation**

Valve-sparing root replacement has evolved from Yacoub's original remodeling procedure to the current David V reimplantation procedure. These two operations have sparked many debates over which is the optimal procedure to restore the natural anatomy and physiology of the aortic valve.

It has been argued that the remodeling procedure is superior to the reimplantation procedure in recreating native aortic root physiology because remodeling maintains the independent mobility of the individual sinus segments. Sinus segment mobility is crucial to facilitating changes in aortic root distensibility throughout the cardiac cycle. Root expansion and contraction throughout systole and diastole is thought to maximize blood flow through the valve apparatus while minimizing stress and strain on the leaflets. Based upon echocardiography data evaluating valve opening and closing characteristics, patients who received a remodeling procedure displayed more physiologic leaflet movements throughout the cardiac cycle compared to patients who underwent a reimplantation procedure inside a straight tube graft (27). Remodeling also preserves the dynamic properties of the annulus which becomes rigid when it is confined by a Dacron graft in the reimplantation technique.

The main arguments for the superiority of the reimplantation procedure is that the remodeling procedure fails to stabilize the annulus, which is important in preventing future annular dilatation, especially in patients with annuloaortic ectasia, Marfan syndrome or other connective tissue disorders. David provided data to support this theory by comparing the results of the remodeling and reimplantation procedures in his own personal series of valve-sparing root replacements in Marfan patients. Using echocardiographic measurements of the different components of the reconstructed aortic root, David showed that patients undergoing the remodeling procedure had progressive dilatation of the aortic annulus and neo-sinus segment over a 13 year period. The annular dilatation occurred even in patients who received an annuloplasty as an adjunctive part of their remodeling procedure. Annular and sinus dimensions were unchanged in patients who received a reimplantation procedure. This translated into more stability in aortic valve function in the reimplantation cohort with regards to progression of aortic insufficiency over time. David hypothesized

The contribution of the shape of the sinus segments to minimizing stress and strain on the cusps and has led to the creation of the Valsalva graft, a graft with premade spherical sinus segments (6) (Vascutek, Renfrewshire, Scotland). In 2010, DePaulis reported a multi-center study from 8 Italian surgeons reporting the long-term results of performing the reimplantation technique with the Valsalva graft in 278 patients. 15% of patients had Marfan syndrome, 11% had bicuspid aortic valves, and 5% of patients underwent valve-sparing procedures in the setting of an acute Type A dissection. 49% of patients had preoperative moderate-severe aortic insufficiency. Operative mortality was 1.8%. At 10 year follow-up, survival was 95% and freedom from significant aortic insufficiency was 88%. 17 patients underwent subsequent AVR for a 10 year freedom from reoperation of on the aortic valve of 91%. The results of this multi-center study highlights the reproducibility of the David V procedure. Although many surgeons prefer to tailor their own graft, the use of a standardized, commercially available graft which has proven excellent long-term valve

Valve-sparing root replacement has evolved from Yacoub's original remodeling procedure to the current David V reimplantation procedure. These two operations have sparked many debates over which is the optimal procedure to restore the natural anatomy and physiology

It has been argued that the remodeling procedure is superior to the reimplantation procedure in recreating native aortic root physiology because remodeling maintains the independent mobility of the individual sinus segments. Sinus segment mobility is crucial to facilitating changes in aortic root distensibility throughout the cardiac cycle. Root expansion and contraction throughout systole and diastole is thought to maximize blood flow through the valve apparatus while minimizing stress and strain on the leaflets. Based upon echocardiography data evaluating valve opening and closing characteristics, patients who received a remodeling procedure displayed more physiologic leaflet movements throughout the cardiac cycle compared to patients who underwent a reimplantation procedure inside a straight tube graft (27). Remodeling also preserves the dynamic properties of the annulus which becomes rigid when it is confined by a Dacron graft in the

The main arguments for the superiority of the reimplantation procedure is that the remodeling procedure fails to stabilize the annulus, which is important in preventing future annular dilatation, especially in patients with annuloaortic ectasia, Marfan syndrome or other connective tissue disorders. David provided data to support this theory by comparing the results of the remodeling and reimplantation procedures in his own personal series of valve-sparing root replacements in Marfan patients. Using echocardiographic measurements of the different components of the reconstructed aortic root, David showed that patients undergoing the remodeling procedure had progressive dilatation of the aortic annulus and neo-sinus segment over a 13 year period. The annular dilatation occurred even in patients who received an annuloplasty as an adjunctive part of their remodeling procedure. Annular and sinus dimensions were unchanged in patients who received a reimplantation procedure. This translated into more stability in aortic valve function in the reimplantation cohort with regards to progression of aortic insufficiency over time. David hypothesized

durability has both simplified and standardized the procedure (26).

**8. Remodeling vs reimplantation** 

of the aortic valve.

reimplantation technique.

that the reason for the progression of dilatation in the remodeling cohort, even in the presence of an annuloplasty is that either the small amount of remnant connective tissue between the annuloplasty line and the remodeling suture line dilated, or the annuloplasty sutures cut through the abnormal fibrous tissue of the LVOT (28). David abandoned the use of the remodeling procedure in favor of reimplantation for patients with Marfan syndrome in 1998.

It has been recognized by multiple surgeons who perform both procedures that the remodeling procedure is a simpler, faster procedure as it requires one less suture line and requires less dissection and mobilization of the root (29, 30). The David V is a considerably more complex procedure, but it allows the surgeon the flexibility to adjust all of the components of the aortic root complex in order to achieve normal physiologic function. Despite its complexity, it has gained worldwide adoption and is the procedure of choice by the majority of surgeons who perform valve-sparing root replacements. Furthermore, many surgeons have published modifications of the David V technique with excellent results (31, 32, 33, 34).

Both the remodeling and the reimplantation procedures have demonstrated excellent longterm aortic valve durability. The two operations should be viewed as complementary rather than competing procedures. Most surgeons recommend that patients with annuloaortic ectasia, Marfan syndrome and other connective tissue disorders are best served by a reimplantation procedure. The remodeling procedure should be reserved for older patients with a normal aortic annulus ((≤25mm woman, ≤27mm man) (17, 34)
