**5. Implantation techniques**

removed from around the annulus. Before sizing the prosthesis, the left ventricular cavity is

The stented prostheses must fit snugly in the annulus, because a very loose or tight fit indicates inadequate effective orifice area (patient-prosthesis mismatch) or oversizing the prosthesis. For the truly measurement of a stented valve, the seizer should be inserted through the aortic annulus and the same (supra-annular) or one number smaller (intra-annular) stented pros‐

Sizing a stentless bioprosthesis is different from stented valves. The most important phase is the choice of an appropriate stentless bioprosthesis, and measurement of the aortic annulus must be done with the seizer that corresponds to the specific bioprosthesis. The true seizer should be chosen to implant the appropriate tissue valve with the optimum size. If the prosthetic valve is too small, the inflow end obstructs the EOA which increases transvalvular gradient and the outflow end is stretched out with decreased leaflet coaptation which causes more regurgitation. On the other hand, oversizing to fit a larger sinotubular junction leads to buckling of the inflow end which can produce both relative stenosis and regurgitation as well as harmful turbulent flow. How the stentless valves sized and implanted will influence its function and durability in future. The larger surface area of the cusps allows greater coaptation area which reduces the risk of bioprosthesis regurgitation. This relatively larger bioprosthesis can simplify replacement, especially the running sutures for all sinuses. But, it is imperative to avoid over-sizing of stentless valves with the tubular structure achieved by three tabs on the commissures, and if sizing is uncertainty the smaller prosthesis should be implanted. In normal aortic root, the diameter of the aortic annulus is 10-15% larger than those of the sinotubular junction and measurement of the aortic annulus is the correct way to choice an appropriate sized stentless valve. However, most patients with calcific aortic stenosis have an abnormal aortic root and the relationship between both diameters is usually altered. In this situation, the diameter of the sinotubular junction is more important because the three commissures of stentless valves are secured at approximately the level of the sinotubular

A cylindrical silicon seizer is more practical to measure the true valve size when both the annulus and the sinotubular junction are measured. The rule is that the sinotubular junction should be dominate during measuring and if there is a major difference (> 3 mm) subcoronary implantation technique can be not used because the commissures of stentless valves are pulled outward and cause valvular insufficiency and an alternative technique (root replacement) or stented bioprosthesis must be used. Supra-annular sizing is the best measurement method to choice an appropriate stentless bioprosthesis, especially during single suture line technique. I prefer this more practical way and put the appropriate seizer into the aortic root in supraannular position (not into the annulus) where I put continuous proximal suture line, so I can choice an acceptable size that is equal to the sinotubular junction size or one number larger stentless prosthesis can be chosen if the seizer fits aortic orifice tightly in patients with aortic root enlargement. Trans-annular measurement is adequate to get a fit stentless valve for

junction if not the full-root replacement technique will be used.

flushed and irrigated with saline solution.

*4.1.4. Sizing the stentless aortic bioprosthesis*

thesis must be chosen.

422 Calcific Aortic Valve Disease

Stentless aortic biologic prostheses can be different in origin: autogenous, homogenous, heterogeneous. Procuring of aortic auto- or homograft is not easy, but production of xenografts is a sufficiently technical supply of the industry for the treatment of aortic valve diseases. All stentless biologic valves can be implanted using different techniques: the subcoronary method, the full root implantation technique, and the root inclusion alternative.

The subcoronary technique is the simplest method for implantation, and either a porcine root can be adapted intra-operatively or a prefabricated tissue valve can be utilized. The main advantages are to avoid the manipulation of coronary ostia and bleeding from suture lines. The disadvantages could be difficulties occurring in the small aortic annulus and calcified aortic root, and possibilities of valve insufficiency by changing the shape of the stentless valve in a diseased aortic root [31]. Subcoronary implantation technique can be performed in two methods: double suture lines (classic) or single suture line (simple) approach.

In classical subcoronary implantation technique, stentless valves are fixed into the host aortic root using double suture lines. The first suture line attaches the inflow site of the stentless bioprosthesis in the left ventricular outflow tract: annular suture line. The second suture line, which is constructed using 1 or 3 continuous sutures, connects the outflow site of the prosthesis with the aortic wall below the coronary ostia: supra-annular suture line. The first suture line consists usually of interrupted sutures, but to reduce cross-clamp and cardiopulmonary times a continuous suture can be preferred [32]. Because the conventional continuous inflow suture line can increase the postoperative heart block risk, an alternative subcoronary technique has been reported in which the inflow suture line is raised at the level of right-non-coronary commissure [33].

The single suture line technique is a simple, quick, safe and reliable method to replace the native aortic valve with a stentless valve. This approach is used for implantation of scalloped new generation tissue valves in supra-annular position and placement of the sutures below or through the annulus should be avoided. Running sutures avoid any prosthetic dead space between prosthetic valve and native aortic wall, and selecting a prosthesis a size larger than the host annulus minimizes the stress on the suture lines. These new generation pericardial valve can have manufactured scalloped design [34] or it can be prepared by trimming away all the extra tissue of the valve inflow side ond scalloping the outflow side [35]. If stentless prostheses are designed with a tubular structure, the tabs on the commissures should be attached to the aortic wall [36].

The total root technique requires reimplantation of coronary arteries using the button techni‐ que. The main advantages are normal physiological shape of the aortic root and choice of a larger valve in small aortic annulus, and both avoid any patient-prosthesis mismatch. The total root technique also prevents torsions of the commissures which avoiding postoperative prosthetic dysfunction. The main disadvantages are implantation difficulties, requirement of interposition a vascular tubular graft between xenograft and native ascending aorta, and xenograft aortic wall calcification making reoperation difficulty. The learning curve seems to be more pronounced when using the total root technique, whereas single suture line technique may be also performed by young surgeons without any problem. Surgeons decide on their experience and the patient's anatomy pre- and intra-operatively which approach with appropriate stentless bioprosthesis type they will use for AVR. Isolated AVR using the subcoronary technique is the best and easiest way in calcific aortic stenosis and using single suture line technique increases the success of implantation a stentless xenograft.

lus as the baseline line, and all sutures are tied on the skirt. If the prosthesis has three own sinuses, at least the two sinuses facing the native left and right coronary ostia are scalloped out below the level of those recipient coronaries, leaving a 4-5 mm rim of pros‐ thetic tissue behind. To suture sinuses of bioprosthesis to the native aortic sinuses, three continuous suture lines (5/0 polypropylene) are started in the nadir of each sinus below the native coronary ostia and in the nadir of the non-coronary sinus and progress upward to the top of three commissures (supra-annular suture line), taking care not to buckle the stentless tissue or distort the positions of the commissural posts. The sutures are taken outside the aorta, buttressed with a pledget and tied together. The deep bites of continu‐ ous sutures on the aortic sinuses can be transverse or horizontal, but they must be fullthickness at the host aortic wall. The broad bites must be taken on the aortic sinuses of bioprosthesis to avoid any space under device. It is also important to pass the needle well away from the margin of the stentless cusp attachment and not to injury the cusps. If the non-coronary sinus of the stentless valve is kept intact (modified subcoronary technique), it is not necessary to use the third suture, and the distal suture line is completed by run‐ ning along the top to join the first two sutures. A stay suture (pledgeted 2/0 Ticron) may be placed at the top of each commissure to achieve 3D geometric shape of the device. If it is necessary the tops are trimmed down to the level of the native aorta. The aortotomy is closed with double continuous pledgeted sutures (4/0 polypropylene) beginning from

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425

It is a simple modification of the subcoronary technique and it can be performed according to

Classical subcoronary stentless valves could be implanted with only supra-annular running suture line that places the stentless annulus above and along the native annulus up and around each commissure (Sorin Freedom Solo, CryoLife O'Brien). In this approach, the device should fit the supra-annular area because the aortic trimmed wall of stentless valves is sutured and attached only with proximal supra-annular suture line directly to native aortic sinuses in supra-annular position. Three polypropylene sutures are started at the nadir of each sinus and brought progressively up to each commissural tip with the ends brought outside the aorta for tying (as described above). Because the stentless valve will be placed supra-annular we can choice a 1 or 2 number larger size than the true annular-size and that prevents any transvalv‐

An alternative approach must be preferred in some stentless prostheses designed as having a tubular structure. The outflow orifice is supported by 3 commissural tabs at the distal junction of the leaflets. Inflow implantation is performed with the same running suture line, but the tops of three commissures are equipped at an appropriate location with stay sutures (pledg‐ etless 2/0 Ticron) tied on the outside of the aorta (3f ATS, Shelhigh Superstentless). These tabs are sewn onto the patient's aortic wall, thereby maintaining the tubular integrity of the prosthesis. It is imperative to achieve true-sizing. Should uncertainty arise, the smaller prosthesis should be implanted because larger prosthesis can block a rapid and unobstructed

each edge.

ular gradient.

**5.2. Single suture line technique**

the design of stentless valve.

The direct suture of autologous pericardium to the aortic wall creating a new aortic valve does not need any supporting stent, sewing ring or cuff, allowing to rebuilt 3 symmetrical aortic cusps independent of the geometry of the native aortic valve. Harvesting a circular pericardi‐ um about 8-10 cm in diameter, treating with glutaraldehyde, sizing-cutting-shaping (a trefoil) with a specially designed instrument, and suturing the cut pericardium mounted on a tissue holder are the steps of this technique which does not take more time. The important goal is to reconstruct a newly geometrically symmetric valve and to ensure adequate coaptation with no prolapse. the suture technique is similar to the single suture line technique and running sutures are placed onto supra-annular aortic wall.

#### **5.1. Subcoronary implantation technique**

This approach is a simple method to implant a stentless bioprosthesis. In spite of the only handicap is the inexperience in this field, geometric thinking is the key point to perform a successful stentless AVR using this approach. A transverse aortotomy helps to image 3D shape of the aortic root which simplifies sizing and implanting a stentless valve. The proximal suture line is performed with the simple interrupted suture technique. This technique requires 18-24 sutures (4/0 Ticron or Polypropylene) which are placed in a cir‐ cular plane coursing through the aortic annulus (annular suture line) and passed through the inflow end of the stentless valve (subannular suture line). All sutures are passed through the Dacron skirt of the bioprosthesis just below the lowest aspect of the cusps, but the sutures at the native commissures must be passed through the same level of pros‐ thetic commissures to create a geometrical shape without any distortion. It is also impor‐ tant not to injury or perforate the prosthetic cusps when the needles are passed through the skirt of the stentless valve. If the aortic annulus is weakened or destroyed pledgeted sutures (4/0 Ticron) should be placed in subannular position to hold suture securely, which provides satisfactory buttressing effect and repairs annular ruptures. Because xeno‐ grafts are not as pliable as homografts and its inversion into the left ventricle followed by being pulled up into the aorta may damage the device, I never use this maneuver. The prosthesis is lowered into the aortic root and sutured with its annulus to the aortic annu‐ lus as the baseline line, and all sutures are tied on the skirt. If the prosthesis has three own sinuses, at least the two sinuses facing the native left and right coronary ostia are scalloped out below the level of those recipient coronaries, leaving a 4-5 mm rim of pros‐ thetic tissue behind. To suture sinuses of bioprosthesis to the native aortic sinuses, three continuous suture lines (5/0 polypropylene) are started in the nadir of each sinus below the native coronary ostia and in the nadir of the non-coronary sinus and progress upward to the top of three commissures (supra-annular suture line), taking care not to buckle the stentless tissue or distort the positions of the commissural posts. The sutures are taken outside the aorta, buttressed with a pledget and tied together. The deep bites of continu‐ ous sutures on the aortic sinuses can be transverse or horizontal, but they must be fullthickness at the host aortic wall. The broad bites must be taken on the aortic sinuses of bioprosthesis to avoid any space under device. It is also important to pass the needle well away from the margin of the stentless cusp attachment and not to injury the cusps. If the non-coronary sinus of the stentless valve is kept intact (modified subcoronary technique), it is not necessary to use the third suture, and the distal suture line is completed by run‐ ning along the top to join the first two sutures. A stay suture (pledgeted 2/0 Ticron) may be placed at the top of each commissure to achieve 3D geometric shape of the device. If it is necessary the tops are trimmed down to the level of the native aorta. The aortotomy is closed with double continuous pledgeted sutures (4/0 polypropylene) beginning from each edge.

#### **5.2. Single suture line technique**

The total root technique requires reimplantation of coronary arteries using the button techni‐ que. The main advantages are normal physiological shape of the aortic root and choice of a larger valve in small aortic annulus, and both avoid any patient-prosthesis mismatch. The total root technique also prevents torsions of the commissures which avoiding postoperative prosthetic dysfunction. The main disadvantages are implantation difficulties, requirement of interposition a vascular tubular graft between xenograft and native ascending aorta, and xenograft aortic wall calcification making reoperation difficulty. The learning curve seems to be more pronounced when using the total root technique, whereas single suture line technique may be also performed by young surgeons without any problem. Surgeons decide on their experience and the patient's anatomy pre- and intra-operatively which approach with appropriate stentless bioprosthesis type they will use for AVR. Isolated AVR using the subcoronary technique is the best and easiest way in calcific aortic stenosis and using single

suture line technique increases the success of implantation a stentless xenograft.

sutures are placed onto supra-annular aortic wall.

**5.1. Subcoronary implantation technique**

424 Calcific Aortic Valve Disease

The direct suture of autologous pericardium to the aortic wall creating a new aortic valve does not need any supporting stent, sewing ring or cuff, allowing to rebuilt 3 symmetrical aortic cusps independent of the geometry of the native aortic valve. Harvesting a circular pericardi‐ um about 8-10 cm in diameter, treating with glutaraldehyde, sizing-cutting-shaping (a trefoil) with a specially designed instrument, and suturing the cut pericardium mounted on a tissue holder are the steps of this technique which does not take more time. The important goal is to reconstruct a newly geometrically symmetric valve and to ensure adequate coaptation with no prolapse. the suture technique is similar to the single suture line technique and running

This approach is a simple method to implant a stentless bioprosthesis. In spite of the only handicap is the inexperience in this field, geometric thinking is the key point to perform a successful stentless AVR using this approach. A transverse aortotomy helps to image 3D shape of the aortic root which simplifies sizing and implanting a stentless valve. The proximal suture line is performed with the simple interrupted suture technique. This technique requires 18-24 sutures (4/0 Ticron or Polypropylene) which are placed in a cir‐ cular plane coursing through the aortic annulus (annular suture line) and passed through the inflow end of the stentless valve (subannular suture line). All sutures are passed through the Dacron skirt of the bioprosthesis just below the lowest aspect of the cusps, but the sutures at the native commissures must be passed through the same level of pros‐ thetic commissures to create a geometrical shape without any distortion. It is also impor‐ tant not to injury or perforate the prosthetic cusps when the needles are passed through the skirt of the stentless valve. If the aortic annulus is weakened or destroyed pledgeted sutures (4/0 Ticron) should be placed in subannular position to hold suture securely, which provides satisfactory buttressing effect and repairs annular ruptures. Because xeno‐ grafts are not as pliable as homografts and its inversion into the left ventricle followed by being pulled up into the aorta may damage the device, I never use this maneuver. The prosthesis is lowered into the aortic root and sutured with its annulus to the aortic annu‐ It is a simple modification of the subcoronary technique and it can be performed according to the design of stentless valve.

Classical subcoronary stentless valves could be implanted with only supra-annular running suture line that places the stentless annulus above and along the native annulus up and around each commissure (Sorin Freedom Solo, CryoLife O'Brien). In this approach, the device should fit the supra-annular area because the aortic trimmed wall of stentless valves is sutured and attached only with proximal supra-annular suture line directly to native aortic sinuses in supra-annular position. Three polypropylene sutures are started at the nadir of each sinus and brought progressively up to each commissural tip with the ends brought outside the aorta for tying (as described above). Because the stentless valve will be placed supra-annular we can choice a 1 or 2 number larger size than the true annular-size and that prevents any transvalv‐ ular gradient.

An alternative approach must be preferred in some stentless prostheses designed as having a tubular structure. The outflow orifice is supported by 3 commissural tabs at the distal junction of the leaflets. Inflow implantation is performed with the same running suture line, but the tops of three commissures are equipped at an appropriate location with stay sutures (pledg‐ etless 2/0 Ticron) tied on the outside of the aorta (3f ATS, Shelhigh Superstentless). These tabs are sewn onto the patient's aortic wall, thereby maintaining the tubular integrity of the prosthesis. It is imperative to achieve true-sizing. Should uncertainty arise, the smaller prosthesis should be implanted because larger prosthesis can block a rapid and unobstructed opening, whereas to small prosthesis restricts of fully leaflet-opening. The same problem can also occur with an excessive or insufficient distal traction on the tabs.

marked annulus using 4–0 polypropylene sutures. Each running suture starting from the base of the leaflet cusp ends at each commissure where it passes through to the outside of the aorta, at which point the knot is tied. The commissures are then securely fixed by passing another mattress suture from inside the commissure to outside the aorta where it is tied. Leaflet symmetry and coaptation are assessed directly at the end of the procedure before closing the

Stentless Bioprostheses for Aortic Valve Replacement in Calcific Aortic Stenosis

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Aortic valve replacement with prosthetic heart valves is the treatment of choice for calcific aortic valve stenosis. Stentless valves are the best option with larger EOA and lower trans‐ valvular gradient, but technically the implantations of these valves are more demanding resulting in longer operation times. However, important comorbid conditions in elderly patients referred for aortic valve replacement require alternative treatment options with possible reductions of the extracorporeal bypass and cross-clamp times and reliable hemody‐ namic features. In order to comply with these requirements, transcatheter (transfemoral or transapical) valves and sutureless surgical valves have been developed. The transcatheter techniques have the advantage of being performed without circulatory bypass but leaving the aortic calcifications in place, thereby resulting in a high degree of paravalvular insufficiency, atrioventricular block and strokes [37]. The surgical approach has the advantage of removing all calcifications and the valves can be optimally implanted, resulting in minimal paravalvular leak with a low incidence of atrioventricular block and strokes; however, it requires cardio‐ pulmonary bypass. The design of sutureless bioprosthesis stems from the intention to offer an alternative to traditional flexible stentless prostheses using conventional open-heart surgery. Sutureless new designed bioprosthesis is a trileaflet bovine or equine pericardial valve mounted on an expandable metal frame in nitinol (equiatomic alloy of nickel and titanium). New designed stentless bioprostheses have several advantages: reducing cross-clamp and cardiopulmonary bypass times, reducing related risk by placing of proximal sutures, less risk of tearing the aortic annulus and wall, avoiding damage of the bundle of His, preventing foreign particle embolization. The primary benefit of this aortic bioprosthesis is the potential for surgeons to provide the same gold standard outcomes of traditional surgical AVR but without the need for sutures, thereby facilitating less invasive or minimally invasive proce‐

The transverse aortic incision is performed 1 cm above the sinotubular junction to preserve a segment of the ascending aorta above the prosthetic valve. Severe calcific aortic valve is removed and aortic annulus should be decalcified for implantation (it is not necessary a complete decalcification). To ensure the correct positioning and orientation of the prosthesis guide-suture(s) can be used. Avoidance of proximal suture lines makes the procedure easier. The architectural design of this new kind of bioprosthesis allows perfect function after it adapts itself to the aortic root. They have two cylindrical ring segments: 'outflow ring' comprises straight posts designed to support the valve and 'inflow ring' allows the prosthesis to be anchored to the aortic root in the Valsalva sinuses and reaches a final diameter compatible with the aortic root. The configuration of the stentless valve is perfect which allows higher

aortotomy.

dures.

**5.6. Sutureless implantation technique**

#### **5.3. Root inclusion technique**

If the original cylindrical shape of the bioprosthetic root devices wants to be preserved without replacement of the native aortic root to avoid bleeding complication, the root inclusion technique can be chosen. A glutaraldehyde-treated porcine aortic root is implanted inside the patient's aortic root. But this technique is more difficult because both native coronary ostia should be anastomosed to the prosthesis like in classic Bentall procedure. After transverse aortotomy a proximal suture line is performed like the subcoronary technique in a circular plane coursing below the commissures. Appropriate opening for coronary ostia are made by excising the sinuses facing the right and left main coronary ostia and then both are sutured continuously (5/0 polypropylene). The only difference between the root inclusion and subcoronary techniques is that the complete sinotubular junction of the stentless valve is preserved. This method is not used nowadays, and if this technique is preferred it should not be used unless the root is large enough to place 23-mm or larger prosthetic root.

#### **5.4. Root replacement technique**

Complete replacement of the native aortic root is last preference for those devices. This technique is used mostly during auto- or homograft replacement. A part of the patient's ascending aorta with total aortic root is excised and a new glutaraldehyde-treated porcine aorta with total aortic root is inserted using a single proximal and distal suture lines. Only indication to prefer this approach is an extended pathology through aortic root (endocarditis, annular abscess, porcelain aorta, dissection) if a stentless valve is used. Since the tubular 3D geometry is not altered, its factory-tested performance is not affected by the implantation. All aortic root is excised and both coronary ostia are separated from the root. The valve seizer should fit in the aortic annulus and 1 or 2 number bigger stentless bioprosthesis is chosen. Depending on the anatomical details of the native right coronary artery, the device may be implanted anatomically or rotated to put the porcine left in the patient's right sinus. The proximal suture line is constructed with continuous polypropylene suture or interrupted sutures (4/0). The coronary buttons are re-implanted as the standard fashion (5/0 polypropy‐ lene). The distal end of the bioprosthesis is usually smaller than the distal native aorta, but it can be not a problem during distal anastomosis (4/0 polypropylene).

#### **5.5. Direct suture technique of autologous pericardium**

Truly stentless AVR using autologous pericardium sutured directly onto the aortic wall without supporting stents is a safe and feasible alternative with excellent hemodynamics of the aortic root [11]. With the use of specially designed instruments, the sinotubular junction is sized, the pericardium is placed on a base, and a cutting blade of the matching size is placed on top of the pericardium, which cuts it to the required size and shape (a trefoil). The cut pericardium is then mounted on a tissue holder to facilitate suturing it to the aortic wall. The prepared autologous pericardium is then sutured directly onto the aortic wall close to the marked annulus using 4–0 polypropylene sutures. Each running suture starting from the base of the leaflet cusp ends at each commissure where it passes through to the outside of the aorta, at which point the knot is tied. The commissures are then securely fixed by passing another mattress suture from inside the commissure to outside the aorta where it is tied. Leaflet symmetry and coaptation are assessed directly at the end of the procedure before closing the aortotomy.

#### **5.6. Sutureless implantation technique**

opening, whereas to small prosthesis restricts of fully leaflet-opening. The same problem can

If the original cylindrical shape of the bioprosthetic root devices wants to be preserved without replacement of the native aortic root to avoid bleeding complication, the root inclusion technique can be chosen. A glutaraldehyde-treated porcine aortic root is implanted inside the patient's aortic root. But this technique is more difficult because both native coronary ostia should be anastomosed to the prosthesis like in classic Bentall procedure. After transverse aortotomy a proximal suture line is performed like the subcoronary technique in a circular plane coursing below the commissures. Appropriate opening for coronary ostia are made by excising the sinuses facing the right and left main coronary ostia and then both are sutured continuously (5/0 polypropylene). The only difference between the root inclusion and subcoronary techniques is that the complete sinotubular junction of the stentless valve is preserved. This method is not used nowadays, and if this technique is preferred it should not

be used unless the root is large enough to place 23-mm or larger prosthetic root.

can be not a problem during distal anastomosis (4/0 polypropylene).

**5.5. Direct suture technique of autologous pericardium**

Complete replacement of the native aortic root is last preference for those devices. This technique is used mostly during auto- or homograft replacement. A part of the patient's ascending aorta with total aortic root is excised and a new glutaraldehyde-treated porcine aorta with total aortic root is inserted using a single proximal and distal suture lines. Only indication to prefer this approach is an extended pathology through aortic root (endocarditis, annular abscess, porcelain aorta, dissection) if a stentless valve is used. Since the tubular 3D geometry is not altered, its factory-tested performance is not affected by the implantation. All aortic root is excised and both coronary ostia are separated from the root. The valve seizer should fit in the aortic annulus and 1 or 2 number bigger stentless bioprosthesis is chosen. Depending on the anatomical details of the native right coronary artery, the device may be implanted anatomically or rotated to put the porcine left in the patient's right sinus. The proximal suture line is constructed with continuous polypropylene suture or interrupted sutures (4/0). The coronary buttons are re-implanted as the standard fashion (5/0 polypropy‐ lene). The distal end of the bioprosthesis is usually smaller than the distal native aorta, but it

Truly stentless AVR using autologous pericardium sutured directly onto the aortic wall without supporting stents is a safe and feasible alternative with excellent hemodynamics of the aortic root [11]. With the use of specially designed instruments, the sinotubular junction is sized, the pericardium is placed on a base, and a cutting blade of the matching size is placed on top of the pericardium, which cuts it to the required size and shape (a trefoil). The cut pericardium is then mounted on a tissue holder to facilitate suturing it to the aortic wall. The prepared autologous pericardium is then sutured directly onto the aortic wall close to the

also occur with an excessive or insufficient distal traction on the tabs.

**5.3. Root inclusion technique**

426 Calcific Aortic Valve Disease

**5.4. Root replacement technique**

Aortic valve replacement with prosthetic heart valves is the treatment of choice for calcific aortic valve stenosis. Stentless valves are the best option with larger EOA and lower trans‐ valvular gradient, but technically the implantations of these valves are more demanding resulting in longer operation times. However, important comorbid conditions in elderly patients referred for aortic valve replacement require alternative treatment options with possible reductions of the extracorporeal bypass and cross-clamp times and reliable hemody‐ namic features. In order to comply with these requirements, transcatheter (transfemoral or transapical) valves and sutureless surgical valves have been developed. The transcatheter techniques have the advantage of being performed without circulatory bypass but leaving the aortic calcifications in place, thereby resulting in a high degree of paravalvular insufficiency, atrioventricular block and strokes [37]. The surgical approach has the advantage of removing all calcifications and the valves can be optimally implanted, resulting in minimal paravalvular leak with a low incidence of atrioventricular block and strokes; however, it requires cardio‐ pulmonary bypass. The design of sutureless bioprosthesis stems from the intention to offer an alternative to traditional flexible stentless prostheses using conventional open-heart surgery. Sutureless new designed bioprosthesis is a trileaflet bovine or equine pericardial valve mounted on an expandable metal frame in nitinol (equiatomic alloy of nickel and titanium). New designed stentless bioprostheses have several advantages: reducing cross-clamp and cardiopulmonary bypass times, reducing related risk by placing of proximal sutures, less risk of tearing the aortic annulus and wall, avoiding damage of the bundle of His, preventing foreign particle embolization. The primary benefit of this aortic bioprosthesis is the potential for surgeons to provide the same gold standard outcomes of traditional surgical AVR but without the need for sutures, thereby facilitating less invasive or minimally invasive proce‐ dures.

The transverse aortic incision is performed 1 cm above the sinotubular junction to preserve a segment of the ascending aorta above the prosthetic valve. Severe calcific aortic valve is removed and aortic annulus should be decalcified for implantation (it is not necessary a complete decalcification). To ensure the correct positioning and orientation of the prosthesis guide-suture(s) can be used. Avoidance of proximal suture lines makes the procedure easier. The architectural design of this new kind of bioprosthesis allows perfect function after it adapts itself to the aortic root. They have two cylindrical ring segments: 'outflow ring' comprises straight posts designed to support the valve and 'inflow ring' allows the prosthesis to be anchored to the aortic root in the Valsalva sinuses and reaches a final diameter compatible with the aortic root. The configuration of the stentless valve is perfect which allows higher hemodynamic performance. There are two types of sutureless aortic bioprostheses in the market.

survival > 12 months [46]. Transcatheter AVI can be prefer in patients with severe calcific aortic stenosis if their aortic valve is trileaflet. There are some exclusion criteria in calcific aortic stenosis: en-block calcification (like unicusp), bicuspid aortic valve, severe massive calcifica‐ tion closely coronary ostia, small aortic annulus (< 18 mm) or large aortic orifice (> 25 mm), thoraco-abdominal aortic or peripheral arterial pathologies. Transapical AVI is the another alternative in patients with calcific aortic stenosis associated thoraco-abdominal aortic or

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As experience is gained and technology evolves, new areas will be met with this approaches. The most optional area is bioprosthesis dysfunction requiring reoperation and an attractive option is to use a AVI procedure in which the device is deployed within the previously placed bioprosthesis: valve-in-valve. Valve-in-valve procedures require a large enough bioprosthetic valve inserted at the index operation to prevent patient-prosthetic mismatch with the AVI

Calcific aortic stenosis is a long-term disease and usually associated with other cardiovascular pathologies. Before AVR, all these situations must be reassessmended and case-specific operation procedure and its alternatives must be planned. If we do not think preoperatively that any specific situation needs an intervention intra-operatively, spontaneously home-made resolutions can be also very helpful in the theater when we decide to correct this pathology.

Severe aortic stenosis is usually combined with proximal ascending aorta aneurysm causing by turbulent flow. The gold standard treatment is composite aortic valve and root replacement. Several surgical teams have devised strategies to construct their homemade composite conduits intra-operatively. It can be a mechanical valved conduit with excellent long-term results [47]. If any contra-indication for anticoagulation therapy, a composite bioprosthetic valved conduit will be the best alternative. Because severe calcific aortic stenosis is often an elderly disease, improved durability of bioprostheses stimulates also their use in the setting of ascending aorta replacement if proximal ascending aorta requires replacement in this population. The concept of composite bioprosthetic valved conduits has also been taken up by the industry and these conduits are already commercially available in different sizes. There are several technical options to allow replacement of the aortic root and ascending aorta using either stented or stentless bioprosthesis [48]. There are basically two alternatives to built a composite graft with a stentless bioprosthesis: the subcoronary technique and the full-root

The subcoronary implantation technique requires a tubular graft and double suture lines for device implantation is necessary. A stentless valve is placed inside a Dacron tube graft leaving a proximal free margin (3-5 mm) and the proximal suture line of the stentless bioprosthesis is fixed to the graft with a running mattress suture [49]. The free end of the tube graft is then

peripheral arterial pathologies.

**6. Special situations**

**6.1. Proximal ascending aorta aneurysm**

valve.

technique.

The Perceval S Aortic Bioprosthesis (Sorin Biomedia Cardio Srl, Sallugia, Italy) has been introduced for minithoracotomy incision [38]. After the device is introduced and parachuted down into aortic annulus and checking corrected position, a balloon dilatation of the inflow ring is performed in the Perceval S valve. If the device is in malpositioning the valve can be quickly removed using the 'χ movement' and repositioned [39]. Because there are only three number valves (21, 23, 25), paravalvular leakage can be observed in higher incidence (4.4% postoperatively and 4% during follow-up) which can be a result of either inadequate sizing or due to inappropriate decalcification of the annulus [40]. For an enlarged aorta with a ratio greater than 1.3, the predicted diameter according to body surface area represents a contrain‐ dication for this device. Early mortality (total 2.4%) and late death (total 2.5%) is acceptable with lower transvalvular gradient (10.8 mmHg) at the first postoperative year [41].

The 3f Enable Aortic Bioprothesis (Model 6000; Medtronic Inc, Minneapolis, USA) is more different and the implantation is more easier: after insertion the device into aortic root in the corrected position, only pour warmer saline (> 30°) onto the device to fully deploy the Nitinol frame into its original shape [42]. If malpositioning occurs after complete de‐ ployment, rinsing with chilled saline makes the nitinol stent flexible and enhances reposi‐ tioning until the valve is correctly placed. Early clinical and hemodynamic performances of the 3f aortic bioprosthesis are similar to those of the regular stentless aortic valves, but both parameters could be inconsistent with the established stentless valves during midterm follow-up: unfavorable mean gradient especially with smaller number (≤ 23 mm), in‐ complete left ventricular regression, higher incidence of neurologic complications [43]. However, a multi-center study has shown better early and mid-term results: major para‐ valvular leakage 2.1%, neurologic events 0.7%, lower mean gradient (10.2 mmHg), lower valve-related early mortality rate (1.4%; total 3.6%); lower late mortality rate (1.5%; total 9.6%), excellent freedom from valve-related mortality at 1-year (96.5%; hazard ratio 1.6%/ year), lower paravalvular leakage (0.8%/year) [44].

The analysis of the current outcome of the use of sutureless aortic bioprostheses must take into consideration the preliminary nature of these devices and the relevant implantation learning curve. There are no comparative study analyzing the outcomes of sutureless and stentless bioprostheses, but it can be said that sutureless bioprostheses have better outcome (mortality, neurologic deficit, renal failure, bleeding) than conventional stentless valves in high-risk patients with aortic stenosis (such as older, female, left ventricular dysfunction, calcification in the ascending aorta, previously cardiac operation, pulmonary or renal disease? [45].

#### **5.7. Transcatheter (transfemoral or transapical) aortic valve implantation**

The approval of transcatheter aortic valve implantation (AVI) represents a fundamental change in the management of calcific aortic stenosis by offering an alternative to traditional surgical AVR in carefully selected patients. Patient-selection is very strict nowadays, and AVI is a reasonable alternative to surgical AVR in adults with severe symptomatic calcific aortic stenosis if they have suitable aortic and vascular anatomy for transcatheter AVI and a predicted survival > 12 months [46]. Transcatheter AVI can be prefer in patients with severe calcific aortic stenosis if their aortic valve is trileaflet. There are some exclusion criteria in calcific aortic stenosis: en-block calcification (like unicusp), bicuspid aortic valve, severe massive calcifica‐ tion closely coronary ostia, small aortic annulus (< 18 mm) or large aortic orifice (> 25 mm), thoraco-abdominal aortic or peripheral arterial pathologies. Transapical AVI is the another alternative in patients with calcific aortic stenosis associated thoraco-abdominal aortic or peripheral arterial pathologies.

As experience is gained and technology evolves, new areas will be met with this approaches. The most optional area is bioprosthesis dysfunction requiring reoperation and an attractive option is to use a AVI procedure in which the device is deployed within the previously placed bioprosthesis: valve-in-valve. Valve-in-valve procedures require a large enough bioprosthetic valve inserted at the index operation to prevent patient-prosthetic mismatch with the AVI valve.
