**2. Calcified aortic valve**

#### **2.1. Etiologies of calcification**

There are three main etiologies of aortic stenosis. The location and extent of calcification in the aortic valve varies depending on its etiology (Fig. 1). In rheumatic valvular disease, there is initial thickening and fusion of the cusps with later involvement of the annulus. The fusion of cusps results in the formation of a valve orifice that looks like a fish mouth. There is also severe mitral valve calcification in patients with combined valvular disease. In arteriosclerotic aortic stenosis, calcification is most prominent in the annulus, sinus of Valsalva and ascending aorta. Calcification of the cusps and calcium deposits on them markedly limit cusp opening. In bicuspid aortic stenosis, disease on the annulus is rather mild but fusion of the commissures reduces the valve orifice area and forms a slit-like orifice. Calcification is often present in bicuspid aortic stenosis, but is rather mild compared with that in arteriosclerotic aortic stenosis. rigidity is helpful for evaluating the adequacy of calcium removal. To minimize the chance of perivalvular leakage following valve implantation, the inner aspect of the annulus should be smooth with the sewing cuff of the prosthetic valve sealing the small gaps between the sutures.

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However, excessive removal of calcium may result in perforation of the aortic root or damage of the mitral valve [8]. Fig. 2 summarizes intraoperative transesophageal echocardiography

The extent of calcification should be carefully checked in the annulus and the aorta (described later). It is important to measure the dimensions of the annulus and sinotubular junction. When the latter is equal to or smaller than the former, difficult insertion of the prosthesis may be encountered. Although the valve can be narrowly inserted by distorting the bioprosthetic valve or the aorta, calcification in the aorta or sinotubular junction makes the latter difficult.

Acoustic shadow indicates the presence and extent of calcification. Fig. 3 shows three different degrees of calcification in the annulus of the noncoronary cusp. When it is transmural or continues to the anterior mitral leaflet as shown in Fig. 3C, excessive removal of calcium should

calcification adjacent and coronary orifice to coronary orifice

**Figure 2.** Intraoperative transesophageal echocardiography (TEE) assessment. A: Calcification in the annulus, sinus of Valsalva, and A-AO is assessed. Important measurements are shown. Annular diameter (Da) is usually smaller than the diameter of STJ (Ds) (B). When Ds is equal or smaller than Da (C), difficult insertion of prosthetic valve may be encoun‐

C

LV

Da Ds

LA

STJ

Da Ds

A-AO

Da: annular diameter Ds: diameter of STJ Dc: distance between annulus

(TEE) assessment and several measurements on the calcified aortic valve [9].

be avoided and limited to a reasonable depth.

Ds

tered. (modied from reference 9)

aortotomy level cross-clamp

arterial cannulation

A-AO

R-PA

Dc

A STJ B

Da

calcified annulus

**Figure 1.** Etiologies of aortic stenosis. A: Rheumatic disease initialy occurs on the cusps and extends toward the annu‐ lus. Fusion of the cusps causes a stenotic orifice like a fish mouth. B: Arteriosclerotic disease extends from the aorta toward the cusps. Opening of the cusps is often disturbed by rigidity of the cusps and calcium deposits on them. C: In bicuspid valve, calcification takes place mainly on the cusps.

#### **2.2. Removal of calcium**

A calcified aortic valve can be a cause of arterial embolism resulting in stroke or myocardial infarction [3-5]. A mobile mass is occasionally found attached to the calcified portion of the aortic valve. A calcified aortic valve as well as the presence of a mobile mass can be assessed by transthoracic echocardiography. Computed tomography (CT) is suitable for precisely assessing the presence and extent of calcification in the annulus and the entire aorta [6,7]. As the calcified cusps are resected, calcium in the annulus needs to be adequately removed to allow subsequent sutures for valve implantation. Calcium deposits are hard but easily crumble into pieces. They can be crushed by clamps and removed or can be fragmented by a Cavitron Ultrasound Surgical Aspirator (CUSA). Either way, loosened calcium needs to be carefully eliminated to prevent it from entering the left ventricle and causing stroke, or entering the left coronary artery and causing myocardial infarction. Digital palpation for irregularity and rigidity is helpful for evaluating the adequacy of calcium removal. To minimize the chance of perivalvular leakage following valve implantation, the inner aspect of the annulus should be smooth with the sewing cuff of the prosthetic valve sealing the small gaps between the sutures.

**2. Calcified aortic valve**

500 Calcific Aortic Valve Disease

**2.1. Etiologies of calcification**

There are three main etiologies of aortic stenosis. The location and extent of calcification in the aortic valve varies depending on its etiology (Fig. 1). In rheumatic valvular disease, there is initial thickening and fusion of the cusps with later involvement of the annulus. The fusion of cusps results in the formation of a valve orifice that looks like a fish mouth. There is also severe mitral valve calcification in patients with combined valvular disease. In arteriosclerotic aortic stenosis, calcification is most prominent in the annulus, sinus of Valsalva and ascending aorta. Calcification of the cusps and calcium deposits on them markedly limit cusp opening. In bicuspid aortic stenosis, disease on the annulus is rather mild but fusion of the commissures reduces the valve orifice area and forms a slit-like orifice. Calcification is often present in bicuspid aortic stenosis, but is rather mild compared with that in arteriosclerotic aortic stenosis.

**Figure 1.** Etiologies of aortic stenosis. A: Rheumatic disease initialy occurs on the cusps and extends toward the annu‐ lus. Fusion of the cusps causes a stenotic orifice like a fish mouth. B: Arteriosclerotic disease extends from the aorta toward the cusps. Opening of the cusps is often disturbed by rigidity of the cusps and calcium deposits on them. C: In

A calcified aortic valve can be a cause of arterial embolism resulting in stroke or myocardial infarction [3-5]. A mobile mass is occasionally found attached to the calcified portion of the aortic valve. A calcified aortic valve as well as the presence of a mobile mass can be assessed by transthoracic echocardiography. Computed tomography (CT) is suitable for precisely assessing the presence and extent of calcification in the annulus and the entire aorta [6,7]. As the calcified cusps are resected, calcium in the annulus needs to be adequately removed to allow subsequent sutures for valve implantation. Calcium deposits are hard but easily crumble into pieces. They can be crushed by clamps and removed or can be fragmented by a Cavitron Ultrasound Surgical Aspirator (CUSA). Either way, loosened calcium needs to be carefully eliminated to prevent it from entering the left ventricle and causing stroke, or entering the left coronary artery and causing myocardial infarction. Digital palpation for irregularity and

bicuspid valve, calcification takes place mainly on the cusps.

**2.2. Removal of calcium**

However, excessive removal of calcium may result in perforation of the aortic root or damage of the mitral valve [8]. Fig. 2 summarizes intraoperative transesophageal echocardiography (TEE) assessment and several measurements on the calcified aortic valve [9].

The extent of calcification should be carefully checked in the annulus and the aorta (described later). It is important to measure the dimensions of the annulus and sinotubular junction. When the latter is equal to or smaller than the former, difficult insertion of the prosthesis may be encountered. Although the valve can be narrowly inserted by distorting the bioprosthetic valve or the aorta, calcification in the aorta or sinotubular junction makes the latter difficult.

Acoustic shadow indicates the presence and extent of calcification. Fig. 3 shows three different degrees of calcification in the annulus of the noncoronary cusp. When it is transmural or continues to the anterior mitral leaflet as shown in Fig. 3C, excessive removal of calcium should be avoided and limited to a reasonable depth.

Da: annular diameter Ds: diameter of STJ Dc: distance between annulus

**Figure 2.** Intraoperative transesophageal echocardiography (TEE) assessment. A: Calcification in the annulus, sinus of Valsalva, and A-AO is assessed. Important measurements are shown. Annular diameter (Da) is usually smaller than the diameter of STJ (Ds) (B). When Ds is equal or smaller than Da (C), difficult insertion of prosthetic valve may be encoun‐ tered. (modied from reference 9)

*2.3.2. Supra-annular implantation*

*2.3.3. Interrupted suture*

**3. Calcified aorta**

TEE is helpful for making a decision (Fig. 2A).

the literature for further details on these two methods.

This allows implantation of a prosthetic valve that is one size larger and is commonly used in many institutes (Fig. 4B). A non-everting suture is placed along the annulus. However, this generates a risk of occlusion of the coronary ostium when it is located at an unusually low level. It can be evaluated by CT, but may be missed by coronary angiography. Intraoperative

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Although mattress sutures slightly reduce the circumference of the aortic annulus, interrupted sutures allow insertion of a prosthetic valve with the same size as the annulus (Fig. 4C). This slightly increases the number of sutures required. Since appropriate seating of the sewing ring on the annulus cannot be confirmed by the pledget adjacent to the sewing cuff, it needs to be inspected through the valve by manually opening the leaflet. When the annulus is severely calcified, it is important to prevent a gap between the annulus and sewing ring. Furthermore, cutting of annular tissue should be avoided while the suture is tied. Two other solutions are stentless aortic valve implant [12,13] and apicoaortic conduit [14-16]. The reader should consult

Calcification in the aorta occasionally necessitates modification of the surgical strategy because of the safety of arterial cannulation, aortic cross-clamping, insertion of a root cannula, aortot‐ omy and suture closure of the aorta. Calcification can be precisely assessed by preoperative CT. The principal strategy can be selected based on the CT findings. Intraoperative TEE and/or epiaortic echo may be used to identify the precise location and extent of calcification and atheromatous plaque in the surgical field. Echo-guided marking of calcification on the aorta can be helpful for subsequent surgical procedures. Three-dimensional (3D) TEE is capable of visualizing the entire ascending aorta (Fig. 5). The xPlane mode allows serial sections of the aorta to be scanned from the aortic valve to the aortic arch. The diseased portion of the

aorta can be located by digital compression of the aorta during visualization by TEE.

Fig. 6 demonstrates several TEE images of calcified aortas. Fig. 6A shows a calcified aortic wall just distal to the sinotubular junction, accompanied by acoustic shadow. The aortotomy line needs to be shifted distally. Calcification can take place at the level of the aortic cross-clamp, where the right pulmonary artery crosses behind the ascending aorta (Fig. 6B). Fig. 6C shows calcification at the level of arterial cannulation. The use of epiaortic echo is desirable to accurately locate the site of calcification. Fig. 6D is a TEE image of rather mild calcification. In this case, the aorta could be clamped without cerebral complications. Fig. 6E shows atherom‐ atous plaque on the anterior wall of the ascending aorta at the level of cross-clamping and insertion of the root cannula. Since enhanced CT is not often employed for preoperative assessment before aortic valve replacement, care should be taken to avoid missing such

**Figure 3.** Calcification in the aortic annulus. A: Calcification is present on the cusps, accompanied by acoustic shadow but not in the annulus. B: Calcification in the annulus. C: Calcification extends to the AML.

#### **2.3. Optimizing valve size**

A calcified aortic valve limits the size of the prosthetic valve that can be implanted. When the aortic annulus is too small, patient-prosthesis mismatch can arise that may lead to sustained pressure overload of the left ventricle and subsequent chronic heart failure. A bioprosthetic valve is desirable for elderly patients with poor anticoagulation compliance to minimize the risk of cerebral infarction, or in patients that need antiplatelet therapy (patients with stroke or coronary stents); however, there are occasions where only a small-sized mechanical valve can be inserted due to a small aortic annulus [19]. Several solutions are illustrated in Fig. 4.

#### *2.3.1. Annular dilatation*

To enlarge the annulus, the aortotomy incision line is extended proximally toward the commissure between the left and non-coronary cusps or toward the noncoronary sinus of Valsalva (Fig. 4A) [11]. However, a markedly calcified annulus and/or sinus of Valsalva makes this procedure difficult or even increases the risk of uncontrollable bleeding at the suture line. Preoperative CT assessment or intraoperative TEE is helpful for making a decision.

**Figure 4.** Solutions for small aortic annulus. A: Annular dilation by Manougian procedure. The commissure between LCC and NCC is incised and a patch is placed. B: Supra-annular implant. Care should be taken to avoid an obstruction of coronary artery. C: Interrupted suture. Cutting of annular tissue while tying is a pitfall.

#### *2.3.2. Supra-annular implantation*

This allows implantation of a prosthetic valve that is one size larger and is commonly used in many institutes (Fig. 4B). A non-everting suture is placed along the annulus. However, this generates a risk of occlusion of the coronary ostium when it is located at an unusually low level. It can be evaluated by CT, but may be missed by coronary angiography. Intraoperative TEE is helpful for making a decision (Fig. 2A).

#### *2.3.3. Interrupted suture*

**Figure 3.** Calcification in the aortic annulus. A: Calcification is present on the cusps, accompanied by acoustic shadow

A calcified aortic valve limits the size of the prosthetic valve that can be implanted. When the aortic annulus is too small, patient-prosthesis mismatch can arise that may lead to sustained pressure overload of the left ventricle and subsequent chronic heart failure. A bioprosthetic valve is desirable for elderly patients with poor anticoagulation compliance to minimize the risk of cerebral infarction, or in patients that need antiplatelet therapy (patients with stroke or coronary stents); however, there are occasions where only a small-sized mechanical valve can be inserted due to a small aortic annulus [19]. Several solutions are illustrated in Fig. 4.

To enlarge the annulus, the aortotomy incision line is extended proximally toward the commissure between the left and non-coronary cusps or toward the noncoronary sinus of Valsalva (Fig. 4A) [11]. However, a markedly calcified annulus and/or sinus of Valsalva makes this procedure difficult or even increases the risk of uncontrollable bleeding at the suture line.

**Figure 4.** Solutions for small aortic annulus. A: Annular dilation by Manougian procedure. The commissure between LCC and NCC is incised and a patch is placed. B: Supra-annular implant. Care should be taken to avoid an obstruction

of coronary artery. C: Interrupted suture. Cutting of annular tissue while tying is a pitfall.

Preoperative CT assessment or intraoperative TEE is helpful for making a decision.

but not in the annulus. B: Calcification in the annulus. C: Calcification extends to the AML.

**2.3. Optimizing valve size**

502 Calcific Aortic Valve Disease

*2.3.1. Annular dilatation*

Although mattress sutures slightly reduce the circumference of the aortic annulus, interrupted sutures allow insertion of a prosthetic valve with the same size as the annulus (Fig. 4C). This slightly increases the number of sutures required. Since appropriate seating of the sewing ring on the annulus cannot be confirmed by the pledget adjacent to the sewing cuff, it needs to be inspected through the valve by manually opening the leaflet. When the annulus is severely calcified, it is important to prevent a gap between the annulus and sewing ring. Furthermore, cutting of annular tissue should be avoided while the suture is tied. Two other solutions are stentless aortic valve implant [12,13] and apicoaortic conduit [14-16]. The reader should consult the literature for further details on these two methods.

### **3. Calcified aorta**

Calcification in the aorta occasionally necessitates modification of the surgical strategy because of the safety of arterial cannulation, aortic cross-clamping, insertion of a root cannula, aortot‐ omy and suture closure of the aorta. Calcification can be precisely assessed by preoperative CT. The principal strategy can be selected based on the CT findings. Intraoperative TEE and/or epiaortic echo may be used to identify the precise location and extent of calcification and atheromatous plaque in the surgical field. Echo-guided marking of calcification on the aorta can be helpful for subsequent surgical procedures. Three-dimensional (3D) TEE is capable of visualizing the entire ascending aorta (Fig. 5). The xPlane mode allows serial sections of the aorta to be scanned from the aortic valve to the aortic arch. The diseased portion of the aorta can be located by digital compression of the aorta during visualization by TEE.

Fig. 6 demonstrates several TEE images of calcified aortas. Fig. 6A shows a calcified aortic wall just distal to the sinotubular junction, accompanied by acoustic shadow. The aortotomy line needs to be shifted distally. Calcification can take place at the level of the aortic cross-clamp, where the right pulmonary artery crosses behind the ascending aorta (Fig. 6B). Fig. 6C shows calcification at the level of arterial cannulation. The use of epiaortic echo is desirable to accurately locate the site of calcification. Fig. 6D is a TEE image of rather mild calcification. In this case, the aorta could be clamped without cerebral complications. Fig. 6E shows atherom‐ atous plaque on the anterior wall of the ascending aorta at the level of cross-clamping and insertion of the root cannula. Since enhanced CT is not often employed for preoperative assessment before aortic valve replacement, care should be taken to avoid missing such findings. Palpation of the aorta cannot detect the presence of atheroma. TEE or epiaortic echo is needed to avoid an embolic event.

**3.1. Arterial cannulation and insertion of a root cannula**

**3.2. Aortic cross-clamp**

ed according to the distribution of calcified portion.

Calcification often involves the distal portion of the ascending aorta and makes arterial cannulation difficult (Fig. 6C). Since an adequate space for aortotomy needs to be spared for procedures on the aortic valve, the cannulation site should not be too proximal. Arterial cannulation of a calcified aorta might cause aortic dissection at the time of cannulation and/or difficult hemostasis following decannulation. When aortic cannulation is not desirable, the axillary or femoral artery can be used as an alternative perfusion route. However, in patients with a calcified aorta, there can also be stenosis or atheromatous lesions in the innominate or iliac artery; thus, it is mandatory to check for these lesions before surgery. The insertion site of the root cannula should be carefully determined. Epiaortic echo is helpful for examining the presence and location of calcification and atheroma. A safe placement of the root cannula requires a certain length of nearly normal wall, which allows secure closure of the puncture

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site. When an adequate area is not available, an elastic needle may be used instead.

calcified layer that can lead to aortic dissection or embolism of fragmented calcium.

In cases with severe and diffuse calcification of the aorta (porcelain aorta), concomitant replacement of the ascending aorta should be considered [17-19]. However, in the majority of calcified aortic valve cases, calcification is present but not severe; it is often scattered without apparent atheromatous plaque on the intima. It is important to determine the safety of aorta cross-clamp in all cases, since cross-clamp of a calcified aorta potentially causes fracture of the

**Figure 7.** Strategies for clamping in cases of calcified aorta. When calcification is diffuse and thick or atheromathous plaque is present, cross-clamp is avoided. If calcification is partial and thin without atheroma, the aorta can be clamp‐

Fig. 7 shows the strategy of the author. When calcification is diffuse and thick or atheromatous plaque is present, aortic cross-clamp is avoided. If the calcified layer is partial and not thick, the aorta may be clamped with some fracture of the calcified portion, but without incompetent clamp or the development of dissection. The clamp may be applied as parallel to the calcified wall as possible to minimize fracture of the calcified section and the shear force on the intima. Initially, the ratchet is locked slowly and less deeply. The blood flow in the proximal aorta is checked with TEE before antegrade cardioplegia is given. When there is some leak through

**Figure 5.** Scanning the entire A-AO using xPlane mode. In the midesophageal A-AO long-axis view, the scanning plane orthogonal to the reference plane is tilted from the AV up to the arch level. Short-axis view of A-AO can be visualized.

**Figure 6.** Examples of TEE images of calcified A-AO. A: Calcification of anterior wall just distal to STJ. B: Calcification at the level of cross-clamping (R-PA level). C: Calcification at the arterial cannulation level. D: Mild calcification of A-AO. E: Atheromatous plaque in the A-AO.

#### **3.1. Arterial cannulation and insertion of a root cannula**

Calcification often involves the distal portion of the ascending aorta and makes arterial cannulation difficult (Fig. 6C). Since an adequate space for aortotomy needs to be spared for procedures on the aortic valve, the cannulation site should not be too proximal. Arterial cannulation of a calcified aorta might cause aortic dissection at the time of cannulation and/or difficult hemostasis following decannulation. When aortic cannulation is not desirable, the axillary or femoral artery can be used as an alternative perfusion route. However, in patients with a calcified aorta, there can also be stenosis or atheromatous lesions in the innominate or iliac artery; thus, it is mandatory to check for these lesions before surgery. The insertion site of the root cannula should be carefully determined. Epiaortic echo is helpful for examining the presence and location of calcification and atheroma. A safe placement of the root cannula requires a certain length of nearly normal wall, which allows secure closure of the puncture site. When an adequate area is not available, an elastic needle may be used instead.

#### **3.2. Aortic cross-clamp**

findings. Palpation of the aorta cannot detect the presence of atheroma. TEE or epiaortic echo

**Figure 5.** Scanning the entire A-AO using xPlane mode. In the midesophageal A-AO long-axis view, the scanning plane orthogonal to the reference plane is tilted from the AV up to the arch level. Short-axis view of A-AO can be

**Figure 6.** Examples of TEE images of calcified A-AO. A: Calcification of anterior wall just distal to STJ. B: Calcification at the level of cross-clamping (R-PA level). C: Calcification at the arterial cannulation level. D: Mild calcification of A-AO. E:

is needed to avoid an embolic event.

504 Calcific Aortic Valve Disease

visualized.

Atheromatous plaque in the A-AO.

In cases with severe and diffuse calcification of the aorta (porcelain aorta), concomitant replacement of the ascending aorta should be considered [17-19]. However, in the majority of calcified aortic valve cases, calcification is present but not severe; it is often scattered without apparent atheromatous plaque on the intima. It is important to determine the safety of aorta cross-clamp in all cases, since cross-clamp of a calcified aorta potentially causes fracture of the calcified layer that can lead to aortic dissection or embolism of fragmented calcium.

**Figure 7.** Strategies for clamping in cases of calcified aorta. When calcification is diffuse and thick or atheromathous plaque is present, cross-clamp is avoided. If calcification is partial and thin without atheroma, the aorta can be clamp‐ ed according to the distribution of calcified portion.

Fig. 7 shows the strategy of the author. When calcification is diffuse and thick or atheromatous plaque is present, aortic cross-clamp is avoided. If the calcified layer is partial and not thick, the aorta may be clamped with some fracture of the calcified portion, but without incompetent clamp or the development of dissection. The clamp may be applied as parallel to the calcified wall as possible to minimize fracture of the calcified section and the shear force on the intima. Initially, the ratchet is locked slowly and less deeply. The blood flow in the proximal aorta is checked with TEE before antegrade cardioplegia is given. When there is some leak through the clamp site, the ratchet is advanced. If full clamp is not effective, another straight clamp is added adjacent to the first clamp or conversion to aortic repair is considered, depending on the risk of aortic repair in each individual case. It should be kept in mind that a clamp on the calcified aorta flattens the proximal aorta and narrows the surgical field following aortotomy. In the case shown in Fig. 6D, the aorta was carefully clamped and valve replacement was performed without neurologic sequelae. For porcelain aorta, endovascular clamping may be another option [20].

most important factor that affects the outcomes of aortic valve replacement, especially for calcified aortic valves. Several pitfalls related to myocardial ischemia are shown in Fig. 9.

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**Figure 8.** Visualization of coronary arteries with TEE. A: In short-axis view at the level of sinus of Valsalva, RCA arises from RCS at 6 o'clock position directed to the groove between RA and RV. B: The LCA takes off from LCS at 3 o'clock position. LMT courses behind PA and divides to LAD and LCX. C: In midesophageal AV long-axis view, RCA arises from RCS (C). D: As the probe is rotated counterclockwise, LCA arises from LCS and LMT divides to LAD and LCX. LAD is directed toward the LV apex and LCX courses posteriorly along the atrioventicular groove between LA and LV. E: In 3D

en-face view, distance from AV annulus to the ostia is recognized.

#### **3.3. Aortotomy**

An incision line is determined based on the distribution of calcification. It may be modified from the standard J-shaped incision line to a rather transectional or more oblique and distal incision. In the case shown in Fig. 6A, aortotomy at a more distal level or meticulous removal of calcification is needed. If there is an insufficient margin for suture closure of the aortotomy (at least 1 cm in width), the surgeon should be prepared for difficult suturing. When the calcified portion of the aorta is to be incised and sutured, calcium needs to be carefully removed following aortotomy, but before implanting a prosthetic valve. The use of CUSA is helpful for reducing the amount of calcium, enabling an adequate attachment of the aortic walls during suture closure. A new device for this purpose may be helpful [21].
