**3. Structural and nonstructural durability**

One of the foremost concern of any tissue valve is its long-term patency, because the limited durability represents the main disadvantage of these devices. Tissue valve degeneration causing stenosis or regurgitation is the primer indication for reoperation.

Durability of any kind of stentless bioprosthesis can be affected adversely by internal (struc‐ tural) or external (nonstructural) factors.

Structural valve deterioration (SVD) is a primary tissue failure after biological valve implan‐ tation. A major cause of SVD is cusp tear with consequent aortic regurgitation where urgent or emergent reoperation is necessary due to congestive heart failure and hemolytic anemia. The other major reason is prosthetic valve sclerosis and calcification which could permit an elective reoperation in stable condition. An in vivo animal study has shown that native aortic valves are significantly more distensible at the level of the sinotubular junction, commissures and ascending aorta when compared with all-valve prosthesis [24]. There is no any study to evaluate how the late scar with/without calcification tissue formation spread and effect this distensibility. We can argue that annular calcification developed during follow-up acts similar in native and stentless valves and fixes the aortic annulus. The zero-pressure fixation and antimineralization techniques have improved durability of tissue valves. To avoid from well known limited durability of xenogenic bioprostheses owing to structural degeneration and calcification, the use of autologous pericardium may be an attractive alternative with several advantages: no immune reaction, minimum tissue calcification and pannus formation, excellent hemodynamics and dynamics of the aortic root, no complicated reoperation [11].

(dilatation, calcification) because of higher operative risk. Subcoronary implantation technique is more acceptable approach for isolated AVR with stentless bioprostheses. Technical errors relating to xenograft sizing and failure to achieve appropriate geometry of the xenograft within the aortic root are 2 major reasons for early valve failure. The learning curve associated with subcoronary implantation is the main reason for these technical errors. Suboptimal implanta‐ tion resulting in distortion of the valve or bulking of valve tissue into the outflow tract may be involved in the evolution of higher gradients. Undersizing of xenograft results regurgitation due to handicapping leaflet coaptation, whereas oversizing may cause higher transvalvular gradient due to making leaflet opening difficult. The other error is to decide and apply the wrong implantation technique, especially in small or dilated aortic root, and subcoronary

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419

On the other hand, improvement of the long term patency of an aortic prosthetic valve is dependent on avoidance of paravalvular complications which can be very serious and cause reoperation. Paravalvular regurgitation is a dangerous long-term result of insufficient decalcification, which causes incompetence suturing or suture rupture during follow-up.

Partial dehiscence of the stentless xenograft indeed occurs and that it has a strong predilection for the preserved non-coronary sinus after modified subcoronary technique. Supposedly, proteolytic enzymes from captured blood cells in the dead space between native and donor aortas or the potential usefulness of biologic glues might prevent adequate fusion of the walls

technique might be associated with higher gradient or regurgitation [25].

and healing of the anastomosis [26].

A. Endocarditis

III. Aortic dissection

IV. Left ventricular dilatation

E. Insufficiently decalcification

F. Subvalvular fibrous band

B. Technically implantation errors C. Aortic root enlargement I. Sinotubular junction dilatation

II. Sinus of Valsalva aneurysm (± rupture)

I. Poor decalcification (intra-operatively)

II. Suture rupture or loosening (post-operatively) III. Calcification on the native aorta (follow-up)

D. Partial dehiscence after preserved non-coronary sinus

G. Hematologic problems (hemolysis, thrombocytopenia)

**Table 2.** Non-structural Deterioration (regurgitation or stenosis).

Nonstructural valve deterioration (NSVD) is independent on the xenograft's tissue. In spite of leaflets of xenografts work very well, stentless bioprosthesis shows incompetence. There are several reasons causing prosthetic stenosis or regurgitation (Table 2).

Technical inadequacy during stentless valve implantation cause hemodynamic problems like regurgitation, turbulent flow, uncoaptation or stretching of leaflets which aggregate tissue degeneration. Any increase in mechanical stress causing by surgical implantation techniques has a negative impact on durability. Description of all implantation techniques with their tips is not adequate to avoid iatrogenic valve degeneration, all details of these techniques should be well known. The best way to avoid mechanical stress may be to use the full root replacement technique, but most surgeon do not like to replace the aortic root without any pathology


regression is related to EOA and transvalvular gradient constituted by the prosthetic valve. A significant improvement will occur in all type of valves in the first year, but this improvement is greater and faster with the stentless bioprostheses [20]. A lasting benefit beyond the first year is possible, especially in severely enlarged ventricles [21]. These improvements include mass regression, wall thickening, fractional shortening, and diastolic relaxation. Patients with small aortic annuli or with compromised left ventricular function (EF < 50%) might benefit

One of the foremost concern of any tissue valve is its long-term patency, because the limited durability represents the main disadvantage of these devices. Tissue valve degeneration

Durability of any kind of stentless bioprosthesis can be affected adversely by internal (struc‐

Structural valve deterioration (SVD) is a primary tissue failure after biological valve implan‐ tation. A major cause of SVD is cusp tear with consequent aortic regurgitation where urgent or emergent reoperation is necessary due to congestive heart failure and hemolytic anemia. The other major reason is prosthetic valve sclerosis and calcification which could permit an elective reoperation in stable condition. An in vivo animal study has shown that native aortic valves are significantly more distensible at the level of the sinotubular junction, commissures and ascending aorta when compared with all-valve prosthesis [24]. There is no any study to evaluate how the late scar with/without calcification tissue formation spread and effect this distensibility. We can argue that annular calcification developed during follow-up acts similar in native and stentless valves and fixes the aortic annulus. The zero-pressure fixation and antimineralization techniques have improved durability of tissue valves. To avoid from well known limited durability of xenogenic bioprostheses owing to structural degeneration and calcification, the use of autologous pericardium may be an attractive alternative with several advantages: no immune reaction, minimum tissue calcification and pannus formation, excellent hemodynamics and dynamics of the aortic root, no complicated reoperation [11]. Nonstructural valve deterioration (NSVD) is independent on the xenograft's tissue. In spite of leaflets of xenografts work very well, stentless bioprosthesis shows incompetence. There are

Technical inadequacy during stentless valve implantation cause hemodynamic problems like regurgitation, turbulent flow, uncoaptation or stretching of leaflets which aggregate tissue degeneration. Any increase in mechanical stress causing by surgical implantation techniques has a negative impact on durability. Description of all implantation techniques with their tips is not adequate to avoid iatrogenic valve degeneration, all details of these techniques should be well known. The best way to avoid mechanical stress may be to use the full root replacement technique, but most surgeon do not like to replace the aortic root without any pathology

causing stenosis or regurgitation is the primer indication for reoperation.

several reasons causing prosthetic stenosis or regurgitation (Table 2).

more from stentless prostheses [22,23].

418 Calcific Aortic Valve Disease

tural) or external (nonstructural) factors.

**3. Structural and nonstructural durability**

(dilatation, calcification) because of higher operative risk. Subcoronary implantation technique is more acceptable approach for isolated AVR with stentless bioprostheses. Technical errors relating to xenograft sizing and failure to achieve appropriate geometry of the xenograft within the aortic root are 2 major reasons for early valve failure. The learning curve associated with subcoronary implantation is the main reason for these technical errors. Suboptimal implanta‐ tion resulting in distortion of the valve or bulking of valve tissue into the outflow tract may be involved in the evolution of higher gradients. Undersizing of xenograft results regurgitation due to handicapping leaflet coaptation, whereas oversizing may cause higher transvalvular gradient due to making leaflet opening difficult. The other error is to decide and apply the wrong implantation technique, especially in small or dilated aortic root, and subcoronary technique might be associated with higher gradient or regurgitation [25].

On the other hand, improvement of the long term patency of an aortic prosthetic valve is dependent on avoidance of paravalvular complications which can be very serious and cause reoperation. Paravalvular regurgitation is a dangerous long-term result of insufficient decalcification, which causes incompetence suturing or suture rupture during follow-up.

Partial dehiscence of the stentless xenograft indeed occurs and that it has a strong predilection for the preserved non-coronary sinus after modified subcoronary technique. Supposedly, proteolytic enzymes from captured blood cells in the dead space between native and donor aortas or the potential usefulness of biologic glues might prevent adequate fusion of the walls and healing of the anastomosis [26].

Subvalvular fibrous band is a rare complication resulting significant left ventricular outflow tract obstruction, which can be a derivative of the pannus discovered on the sewing ring of stented valves. The etiology is unknown, but it may result from thrombus formation or inflammation related to host factors. A chronic inflammatory infiltrate composed of lympho‐ cytes and macrophages occurs in equine or porcine stentless valves, which suggests equal immunogenicity among different various biologic graft materials [27].

artery bypass surgery, and patent proximal anastomoses on the ascending aorta can be a serious problem during aortotomy. I have offered a simple aortotomy incision "Reverse U aortotomy" to save proximal anastomoses and if it is necessary to apply direct antegrade

Stentless Bioprostheses for Aortic Valve Replacement in Calcific Aortic Stenosis

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421

Aortic valve stenosis appears with fusion of one or both commissures, thickening and retraction of the cusps, and restriction of effective orifice area. Calcific involvement of native aortic valve is the last step which can be widespread very aggressively: aortic annulus, mitral annulus, aortic root, coronary ostia. The typically pathologic findings of calcific aortic stenosis are discrete, focal lesions on the aortic side of the leaflets. The severe form is characterized by diffuse calcification of the aortic root and the deposits involve the sinuses of Valsalva and the ascending aorta (porcelain aorta). The calcification presents as a cauliflower-like mass within the leaflets and often extends deep into the annulus and surrounding tissues. All these

contiguous anatomical structures can have adverse affects on the surgical techniques.

A surgically complete decalcification of the aortic annulus is an important point. The flexible continuity of the aortic annulus with sub- and supra-annular tissues is indispensable condition to get better durability and hemodynamics with stentless xenografts, and to avoid from a whole aortic root replacement technique, which hinders surgeons to perform AVR with a stentless xenograft. Surgeons must care 1) not to leave any calcific tissue around the aortic annulus, 2) not to allow fragments of calcium to fall into the left ventricle, 3) not to disrupt the annulus as possible, 4) not to detach the anterior mitral leaflet from the annulus (non-coronary sinus), 5) not to rupture subannular muscular septum (right coronary sinus), 6) not to perforate outside

The calcific aortic valve is excised and trimmed with a scissor leaving a 2-3 mm margin at the annulus if the annular margin of the leaflets are healthy. The frequent scenario is conversely that and extensive calcific involvement of the whole aortic annulus is observed very often. First of all, complete resection of the calcific aortic valve should be performed without any compli‐ cation listed above. Excision of the calcific leaflets with a scissor is usually unsuccessful and dangerous because of breaking of calcification and falling calcium debris into the left ventricle. The best alternative to remove the diseased tissue is excision all of them with a lancet (number 15). A folded segment of sponge or tampon is not necessary to place in the left ventricle and it hinders to see the cavity and to remove any calcium particle. The easiest excision with the lancet is to perforate the healthy leaflet near the annulus in partial calcified aortic valve or to begin excision at the commissure between the non-coronary and right coronary leaflets in enbloc calcific aortic valve. Cutting of the calcification is begun at the nearest end and the lancet incises the calcified valve from the healthy annular tissue. The sharp edge of the lancet should be headed toward the calcified valve, and cutting is performed just below of calcification. The whole calcified valve must be incised as en-block, without fragmentation. If calcification is very heavy or invaded into the annulus it can be cut with the scissor and then the residual calcifications will be gently crushed and removed with a rounger. After completion of the aortic valve excision, all residual diseased and/or calcified tissue or particles should be

cardioplegia through proximal anastomoses [30].

*4.1.3. Excision of the calcific aortic valve*

the heart (left coronary sinus).

#### **4.1. Aortic valve surgery**

#### *4.1.1. Cardiopulmonary bypass*

Aortic valve surgery can be performed through a median full sternotomy or upper minister‐ notomy with conventional or minimal skin incision. The distal ascending aorta cannulation is usually the standard approach in most patients, but the arcus aorta or axiller artery can be also cannulated when the ascending aorta should be replaced [28]. A single dual-stage venous cannula is inserted through the right atrium appendage. After cardiopulmonary bypass is initiated the aorta is clamped and cardiac arrest is be achieved with antegrade isothermic blood cardioplegia administered into the aortic root. Myocardial protection is continued due to retrograde cardioplegic cannula during whole procedure, and retrograde cardioplegia is continuously infused whenever clear visulation of the aortic root is not required [29]. Rarely the retrograde cannula cannot be introduced safely into the coronary sinus, in this situation intermittent antegrade isothermic blood cardioplegia is performed using selective coronary ostial cannulation after transverse aortotomy incision. If both approaches are unsuccessful, bicaval cannulation is performed and the retrograde cannula is placed in the coronary sinus under direct vision. A vent cannula is inserted into the left atrium through the right upper pulmonary vein after cross clamp to prevent the left ventricle distention. Mild-moderate hypothermia (30-32°C) is achieved and continued during extracorporeal circulation, and rewarming of patients is started before the closure of the aortotomy.

#### *4.1.2. Aortotomy*

A small transverse aortotomy incision is made initially at least 15 to 20 mm above the origin of the right coronary ostium or the sinotubular junction. The calcific aortic valve and whole aortic root should be investigated under direct vision and decided which approach will be preferred. If the aortic root will not be replaced then the transverse aortotomy incision is extended on both sides until 3D view of the aortic root appears. That helps surgeons for excision of the severe calcific aortic valve, selection of an appropriate stentless bioprosthesis and insertion simple and/or continuous sutures easily and correctly. A transverse aortotomy is also required to image 3D shape of the aortic root which is the main condition for resus‐ pention of the prosthetic commissures and to hold a stentless tissue valve in corrected position for prevention of the iatrogenic valve degeneration. An oblique or hockey-stick incision is preferred very seldom, but it could be useful in patients with small aortic root. If the aortic root is replaced it is excised completely and aortic root implantation technique is performed. Reoperation for severe calcific aortic stenosis is not rare in patients with previously coronary artery bypass surgery, and patent proximal anastomoses on the ascending aorta can be a serious problem during aortotomy. I have offered a simple aortotomy incision "Reverse U aortotomy" to save proximal anastomoses and if it is necessary to apply direct antegrade cardioplegia through proximal anastomoses [30].

#### *4.1.3. Excision of the calcific aortic valve*

Subvalvular fibrous band is a rare complication resulting significant left ventricular outflow tract obstruction, which can be a derivative of the pannus discovered on the sewing ring of stented valves. The etiology is unknown, but it may result from thrombus formation or inflammation related to host factors. A chronic inflammatory infiltrate composed of lympho‐ cytes and macrophages occurs in equine or porcine stentless valves, which suggests equal

Aortic valve surgery can be performed through a median full sternotomy or upper minister‐ notomy with conventional or minimal skin incision. The distal ascending aorta cannulation is usually the standard approach in most patients, but the arcus aorta or axiller artery can be also cannulated when the ascending aorta should be replaced [28]. A single dual-stage venous cannula is inserted through the right atrium appendage. After cardiopulmonary bypass is initiated the aorta is clamped and cardiac arrest is be achieved with antegrade isothermic blood cardioplegia administered into the aortic root. Myocardial protection is continued due to retrograde cardioplegic cannula during whole procedure, and retrograde cardioplegia is continuously infused whenever clear visulation of the aortic root is not required [29]. Rarely the retrograde cannula cannot be introduced safely into the coronary sinus, in this situation intermittent antegrade isothermic blood cardioplegia is performed using selective coronary ostial cannulation after transverse aortotomy incision. If both approaches are unsuccessful, bicaval cannulation is performed and the retrograde cannula is placed in the coronary sinus under direct vision. A vent cannula is inserted into the left atrium through the right upper pulmonary vein after cross clamp to prevent the left ventricle distention. Mild-moderate hypothermia (30-32°C) is achieved and continued during extracorporeal circulation, and

A small transverse aortotomy incision is made initially at least 15 to 20 mm above the origin of the right coronary ostium or the sinotubular junction. The calcific aortic valve and whole aortic root should be investigated under direct vision and decided which approach will be preferred. If the aortic root will not be replaced then the transverse aortotomy incision is extended on both sides until 3D view of the aortic root appears. That helps surgeons for excision of the severe calcific aortic valve, selection of an appropriate stentless bioprosthesis and insertion simple and/or continuous sutures easily and correctly. A transverse aortotomy is also required to image 3D shape of the aortic root which is the main condition for resus‐ pention of the prosthetic commissures and to hold a stentless tissue valve in corrected position for prevention of the iatrogenic valve degeneration. An oblique or hockey-stick incision is preferred very seldom, but it could be useful in patients with small aortic root. If the aortic root is replaced it is excised completely and aortic root implantation technique is performed. Reoperation for severe calcific aortic stenosis is not rare in patients with previously coronary

immunogenicity among different various biologic graft materials [27].

rewarming of patients is started before the closure of the aortotomy.

**4.1. Aortic valve surgery**

420 Calcific Aortic Valve Disease

*4.1.2. Aortotomy*

*4.1.1. Cardiopulmonary bypass*

Aortic valve stenosis appears with fusion of one or both commissures, thickening and retraction of the cusps, and restriction of effective orifice area. Calcific involvement of native aortic valve is the last step which can be widespread very aggressively: aortic annulus, mitral annulus, aortic root, coronary ostia. The typically pathologic findings of calcific aortic stenosis are discrete, focal lesions on the aortic side of the leaflets. The severe form is characterized by diffuse calcification of the aortic root and the deposits involve the sinuses of Valsalva and the ascending aorta (porcelain aorta). The calcification presents as a cauliflower-like mass within the leaflets and often extends deep into the annulus and surrounding tissues. All these contiguous anatomical structures can have adverse affects on the surgical techniques.

A surgically complete decalcification of the aortic annulus is an important point. The flexible continuity of the aortic annulus with sub- and supra-annular tissues is indispensable condition to get better durability and hemodynamics with stentless xenografts, and to avoid from a whole aortic root replacement technique, which hinders surgeons to perform AVR with a stentless xenograft. Surgeons must care 1) not to leave any calcific tissue around the aortic annulus, 2) not to allow fragments of calcium to fall into the left ventricle, 3) not to disrupt the annulus as possible, 4) not to detach the anterior mitral leaflet from the annulus (non-coronary sinus), 5) not to rupture subannular muscular septum (right coronary sinus), 6) not to perforate outside the heart (left coronary sinus).

The calcific aortic valve is excised and trimmed with a scissor leaving a 2-3 mm margin at the annulus if the annular margin of the leaflets are healthy. The frequent scenario is conversely that and extensive calcific involvement of the whole aortic annulus is observed very often. First of all, complete resection of the calcific aortic valve should be performed without any compli‐ cation listed above. Excision of the calcific leaflets with a scissor is usually unsuccessful and dangerous because of breaking of calcification and falling calcium debris into the left ventricle. The best alternative to remove the diseased tissue is excision all of them with a lancet (number 15). A folded segment of sponge or tampon is not necessary to place in the left ventricle and it hinders to see the cavity and to remove any calcium particle. The easiest excision with the lancet is to perforate the healthy leaflet near the annulus in partial calcified aortic valve or to begin excision at the commissure between the non-coronary and right coronary leaflets in enbloc calcific aortic valve. Cutting of the calcification is begun at the nearest end and the lancet incises the calcified valve from the healthy annular tissue. The sharp edge of the lancet should be headed toward the calcified valve, and cutting is performed just below of calcification. The whole calcified valve must be incised as en-block, without fragmentation. If calcification is very heavy or invaded into the annulus it can be cut with the scissor and then the residual calcifications will be gently crushed and removed with a rounger. After completion of the aortic valve excision, all residual diseased and/or calcified tissue or particles should be removed from around the annulus. Before sizing the prosthesis, the left ventricular cavity is flushed and irrigated with saline solution.

subcoronary implantation in patients with normal aortic root, but preferring one size larger prosthesis is better if full-root replacement technique will be performed or a small aortic root is present. I never suggest to play some traction sutures at the commissures or in the nadir of the annulus to open the aortic orifice. It can be useful during the replacement of a stented valve, but it will be better to release the aortic root in its original shape during sizing stentless valves.

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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 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

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

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

the full root implantation technique, and the root inclusion alternative.

methods: double suture lines (classic) or single suture line (simple) approach.

**5. Implantation techniques**

commissure [33].

attached to the aortic wall [36].

#### *4.1.4. Sizing the stentless aortic bioprosthesis*

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‐ thesis must be chosen.

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

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 subcoronary implantation in patients with normal aortic root, but preferring one size larger prosthesis is better if full-root replacement technique will be performed or a small aortic root is present. I never suggest to play some traction sutures at the commissures or in the nadir of the annulus to open the aortic orifice. It can be useful during the replacement of a stented valve, but it will be better to release the aortic root in its original shape during sizing stentless valves.
