**4. Coronary arteries**

Myocardial protection is one of the most important issues in aortic valve replacement. Left ventricular hypertrophy and/or coronary artery disease is often associated with aortic stenosis. In addition, surgical procedures may potentially cause new myocardial ischemia. Therefore, careful observation of coronary perfusion is essential. Fig. 8 shows visualization of the coronary arteries with TEE. The coronary arteries can be visualized bilaterally in the majority of cases and coronary artery assessment is done routinely in our institute. The ostia of the right and left coronary arteries are depicted in the short-axis view at the level of sinus of Valsalva (Fig. 8 A,B). The right coronary artery travels in the groove between the right atrium and right ventricle, whereas the left coronary artery crosses behind the pulmonary artery. The left main truncus divides into the left anterior descending and left circumflex arteries. The right coronary ostium can also be depicted in the midesophageal aortic valve long-axis view, giving an idea of its distance from the annulus (Fig. 8C).

To further visualize the distal portion of the left coronary artery, the scanning plane is rotated counterclockwise from the midesophageal aortic valve long-axis view (Fig. 8D). The left coronary sinus takes the place of the noncoronary sinus, and the short-axis view of left main truncus appears. The left anterior descending artery courses toward the 6 to 7 o'clock direction. The distal portion of the left circumflex artery is visualized in the atrioventricular groove. With the 3D en face view, the height of coronary take-off can be observed (Fig. 8E). The author meticulously uses TEE for intraoperative assessment of coronary perfusion, because it is the 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.

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

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

Myocardial protection is one of the most important issues in aortic valve replacement. Left ventricular hypertrophy and/or coronary artery disease is often associated with aortic stenosis. In addition, surgical procedures may potentially cause new myocardial ischemia. Therefore, careful observation of coronary perfusion is essential. Fig. 8 shows visualization of the coronary arteries with TEE. The coronary arteries can be visualized bilaterally in the majority of cases and coronary artery assessment is done routinely in our institute. The ostia of the right and left coronary arteries are depicted in the short-axis view at the level of sinus of Valsalva (Fig. 8 A,B). The right coronary artery travels in the groove between the right atrium and right ventricle, whereas the left coronary artery crosses behind the pulmonary artery. The left main truncus divides into the left anterior descending and left circumflex arteries. The right coronary ostium can also be depicted in the midesophageal aortic valve long-axis view, giving an idea

To further visualize the distal portion of the left coronary artery, the scanning plane is rotated counterclockwise from the midesophageal aortic valve long-axis view (Fig. 8D). The left coronary sinus takes the place of the noncoronary sinus, and the short-axis view of left main truncus appears. The left anterior descending artery courses toward the 6 to 7 o'clock direction. The distal portion of the left circumflex artery is visualized in the atrioventricular groove. With the 3D en face view, the height of coronary take-off can be observed (Fig. 8E). The author meticulously uses TEE for intraoperative assessment of coronary perfusion, because it is the

suture closure. A new device for this purpose may be helpful [21].

another option [20].

506 Calcific Aortic Valve Disease

**4. Coronary arteries**

of its distance from the annulus (Fig. 8C).

**3.3. Aortotomy**

**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.

into the coronary artery, because the cannula tip does not fit properly and there is significant leakage. When calcification accompanied by acoustic shadow is present adjacent to the coronary ostium (Fig. 9B), this pitfall may occur. A highly echogenic projection accompanied by acoustic shadow, usually on the side of the sinotubular junction, is a typical TEE finding. Calcification in the aortic root also makes it difficult to locate the right coronary ostium, especially when the sinus wall of Valsalva is rigid and cannot be folded back. Unsuccessful infusion of cardioplegic solution potentially leads to right heart failure, since the right coronary region cannot be adequately perfused via the retrograde approach. Although a large-bore cannula tip does not adequately fit the calcified ostium, a small-caliper cannula causes little leakage but the velocity of jet stream ejected out of the cannula can exceed 2 m/sec, potentially causing intimal damage or dissection. Fig. 9C shows the TEE findings of dissection that occurred in the left coronary artery following cardiopulmonary bypass in a case of difficult coronary perfusion. Although the left coronary artery was intact before bypass, no blood flow was detected during weaning from bypass in the area that was thought to contain the left main truncus. Since the anterior and posterior walls of the left ventricle were akinetic, immediate coronary bypass grafting to the left anterior descending artery was performed. Subsequent epicardial echo revealed a flap in the left main truncus and retrograde blood flow in the left anterior descending artery from the coronary bypass graft that perfused the left circumflex

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Anomalous origin of the right coronary artery is rather rare (Fig. 9D), but is difficult to diagnose based on preoperative coronary angiography. In a case of aortic stenosis with an intact right coronary artery in preoperative coronary angiography, the right coronary ostium could not be found in the right coronary sinus of Valsalva. Selective perfusion of the left coronary artery caused backflow from the right coronary ostium, which was identified at the commissure between the right and left coronary cusps. Calcified protrusion was continuous from the commissure to the ostium. The right coronary artery was successfully perfused, and the calcium at the orifice was left unresected. However, when calcium is exposed without being covered by the sewing ring, there is the potential for thrombus formation adjacent to the right coronary ostium. Following aortic valve replacement, TEE demonstrated that the stent post was located in front of the right coronary ostium, because the stent posts were oriented so that the left coronary ostium was not covered by the stent post. The right coronary artery coursed along the right coronary sinus and could have been inadvertently injured by the surgical

Retrograde cardioplegia is a solution for difficult antegrade coronary perfusion. However, the region perfused by the right coronary artery is poorly protected because the cardioplegic solution predominantly enters the coronary veins along the left coronary artery (great cardiac vein) but not the middle or small cardiac veins. Although the latter may be perfused via collaterals between the veins, this is not certain. Also, in cases where it is difficult to fit the

artery.

procedures.

**4.3. Anomalous origin of the right coronary artery**

**4.4. Myocardial perfusion during cardioplegia**

**Figure 9.** Pitfalls related to coronary artery in aortic valve replacement. A: Short LMT divides to LAD and LCX near the ostium. B: Calcification adjacent to RCA ostium. C: New dissection in the LMT. LMT was intact before bypass (C1), but no flow was detectable during wearing from bypass (C2) associated with akinetic LV. Epicardial echo following coro‐ nary bypass to the LAD shows a flap obstructing the LMT and blood flow from LAD toward LCX (C3). D: Anomalous origin of RCA. RCA was not found in the RCS, but at the commissure between RCC and LCC (D1). Following valve re‐ placement, RCA was seen originating from the commissure in front of the stent post (D2). Schematic illustration of D is shown.

#### **4.1. Short left main truncus**

The left main truncus is occasionally found to be short (Fig. 9A). As the cannula is forcefully thrust into the ostium, the cannula tip may enter either the left anterior descending or left circumflex artery. Any unperfused region of the left ventricle may be poorly protected during the procedure.

#### **4.2. Calcified ostium**

The coronary ostium as well as the surrounding wall of the coronary sinus of Valsalva may be rigid or irregular, occasionally making it difficult to selectively infuse cardioplegic solution into the coronary artery, because the cannula tip does not fit properly and there is significant leakage. When calcification accompanied by acoustic shadow is present adjacent to the coronary ostium (Fig. 9B), this pitfall may occur. A highly echogenic projection accompanied by acoustic shadow, usually on the side of the sinotubular junction, is a typical TEE finding. Calcification in the aortic root also makes it difficult to locate the right coronary ostium, especially when the sinus wall of Valsalva is rigid and cannot be folded back. Unsuccessful infusion of cardioplegic solution potentially leads to right heart failure, since the right coronary region cannot be adequately perfused via the retrograde approach. Although a large-bore cannula tip does not adequately fit the calcified ostium, a small-caliper cannula causes little leakage but the velocity of jet stream ejected out of the cannula can exceed 2 m/sec, potentially causing intimal damage or dissection. Fig. 9C shows the TEE findings of dissection that occurred in the left coronary artery following cardiopulmonary bypass in a case of difficult coronary perfusion. Although the left coronary artery was intact before bypass, no blood flow was detected during weaning from bypass in the area that was thought to contain the left main truncus. Since the anterior and posterior walls of the left ventricle were akinetic, immediate coronary bypass grafting to the left anterior descending artery was performed. Subsequent epicardial echo revealed a flap in the left main truncus and retrograde blood flow in the left anterior descending artery from the coronary bypass graft that perfused the left circumflex artery.

#### **4.3. Anomalous origin of the right coronary artery**

**Figure 9.** Pitfalls related to coronary artery in aortic valve replacement. A: Short LMT divides to LAD and LCX near the ostium. B: Calcification adjacent to RCA ostium. C: New dissection in the LMT. LMT was intact before bypass (C1), but no flow was detectable during wearing from bypass (C2) associated with akinetic LV. Epicardial echo following coro‐ nary bypass to the LAD shows a flap obstructing the LMT and blood flow from LAD toward LCX (C3). D: Anomalous origin of RCA. RCA was not found in the RCS, but at the commissure between RCC and LCC (D1). Following valve re‐ placement, RCA was seen originating from the commissure in front of the stent post (D2). Schematic illustration of D is

The left main truncus is occasionally found to be short (Fig. 9A). As the cannula is forcefully thrust into the ostium, the cannula tip may enter either the left anterior descending or left circumflex artery. Any unperfused region of the left ventricle may be poorly protected during

The coronary ostium as well as the surrounding wall of the coronary sinus of Valsalva may be rigid or irregular, occasionally making it difficult to selectively infuse cardioplegic solution

shown.

the procedure.

508 Calcific Aortic Valve Disease

**4.2. Calcified ostium**

**4.1. Short left main truncus**

Anomalous origin of the right coronary artery is rather rare (Fig. 9D), but is difficult to diagnose based on preoperative coronary angiography. In a case of aortic stenosis with an intact right coronary artery in preoperative coronary angiography, the right coronary ostium could not be found in the right coronary sinus of Valsalva. Selective perfusion of the left coronary artery caused backflow from the right coronary ostium, which was identified at the commissure between the right and left coronary cusps. Calcified protrusion was continuous from the commissure to the ostium. The right coronary artery was successfully perfused, and the calcium at the orifice was left unresected. However, when calcium is exposed without being covered by the sewing ring, there is the potential for thrombus formation adjacent to the right coronary ostium. Following aortic valve replacement, TEE demonstrated that the stent post was located in front of the right coronary ostium, because the stent posts were oriented so that the left coronary ostium was not covered by the stent post. The right coronary artery coursed along the right coronary sinus and could have been inadvertently injured by the surgical procedures.

#### **4.4. Myocardial perfusion during cardioplegia**

Retrograde cardioplegia is a solution for difficult antegrade coronary perfusion. However, the region perfused by the right coronary artery is poorly protected because the cardioplegic solution predominantly enters the coronary veins along the left coronary artery (great cardiac vein) but not the middle or small cardiac veins. Although the latter may be perfused via collaterals between the veins, this is not certain. Also, in cases where it is difficult to fit the coronary perfusion cannula and there is considerable leakage, perfusion of the myocardium is a concern. A myocardial thermometer was conventionally used, but may not be useful in warm heart surgery. Real-time assessment of myocardial perfusion is desired, especially in cases with deteriorated cardiac function. Here, a novel method for noninvasively assessing myocardial perfusion is demonstrated (Fig. 10). The transgastric basal or midventricular shortaxis view is visualized. In pulsed-wave Doppler mode, the sample volume is placed on the myocardium. When this portion of myocardium is perfused, a flow signal is detected. Under selective perfusion of the left coronary artery, blood flow is detected in the anterior wall but not in the inferior wall. As coronary perfusion is discontinued, the flow signal instantaneously disappears. The perfused region is identified by mapping the myocardium. This can be helpful for examining the extent of retrograde delivery of cardioplegic solution.

prosthetic valve. It is readily examined by TEE in the midesophageal long-axis view (Fig. 11A). A minor leak that originates inside of the ring and deviates inwards is transvalvular leak and is not significant (Fig. 11B). When significant leakage is detected in the left ventricular outflow tract that originates outside of the suture ring, perivalvular leakage is probable (Fig. 11C). The assessment of leakage is difficult in cases with concomitant mitral valve replacement. The ring of the prosthetic valve implanted in the mitral position casts an acoustic shadow on the left ventricular outflow tract (Fig. 11D). In such an instance, leakage is assessed in the deep

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**Figure 11.** TEE assessment of prostethic valve following aortic valve replacement. A: Midesophageal long-axis view without abnormal leak from the prosthetic valve. B: Minor transvalvular leak. C: Significant perivalvular leak around the valve. D: Leakage is suspected but visualization is disturbed by the valve in mitral position. E: Deep transgastric view shows mild transvalvular leak F: Blood flow in the entire area of ascending aorta just distal to the prosthetic valve indicates good opening of discs. G,H: Massive transvalvular leak from the bioprosthesis due to everted leaflet.

transgastric long-axis view via the left ventricular apex (Fig. 11E).

**Figure 10.** TEE assessment of myocardial blood flow during cardioplegia. Under selective perfusion to LCA, blood flow is detectable in the anterior wall (A) but not in the inferior wall (B). As selective RCA perfusion is terminated, blood flow detected in the inferior wall (c) instantaneously disappears (D)
