**3. Strategies to avoid aortic atheroma dislogement**

The detection of aortic atheroma does not directly lead to the avoidance of atheroma dislodgement and embolism. The actual avoidance of dislodgement requires a change to the surgical strategy. Thus the detection of atheroma is the important first step, and allows a

Epiaortic Ultrasound Assessment of the Thoracic Aorta in Cardiac Surgery 39

Fig. 2. Freedom to move sites of aortic manipulation. The sites of aortic manipulation are shown for (A) aorta-coronary and (B) Y graft techniques. Construction of aortic anastomosis limits movement of aortic cannulation and clamp sites away from detected atheroma illustrated in the distal ascending and proximal aortic arch. The atheroma is easily avoided by using the exclusive Y graft technique by moving the sites of cannulation and clamping away from the atheroma. (Small star (\*) is antegrade cardioplegia cannulation site; AV is

aortic valve.)

decision to be made that then subsequently leads to the avoidance of embolism. This highlights one of the key difficulties for surgeons. It may be that a surgical alternative is not possible for the patient; or the skill, capability or surgical repertoire of the surgeon themselves limits potential alternative strategies being employed. This may vary with training, experience and technical capability as well as patient factors such as absence of suitable conduits and so forth. Thus there is no commonly applied solution available.

Fig. 1. Ultrasound images of aortic atheroma.

In principle however, there are few significant options available for surgical alteration. In the case of the use of cardiopulmonary bypass, aortic calculation and clamping sites may be altered so as to manipulate the aorta near to but not involving the atheroma. Certain operations preclude alteration of manipulation position, and so alternative sites for aortic cannulation or alternatives for aortic clamping need to be considered. In practice, often the surgeon simply accepts the need to manipulate atheromatous segments of the aorta and proceeds anyway. An example may be the performance of an aortic valve replacement; whereby there is very limited scope for alteration of the aortic incision, and it may not be possible to entirely avoid atheroma in this locality.

Coronary artery bypass surgery provides more opportunity to alter the surgical operation so as to avoid atheroma. The construction of proximal aortic anastomoses is predominantly situated in the mid ascending aorta; the proximal aorta is rarely used as this will kink the grafts and the distal ascending aorta is occupied by the aortic clamp and antegrade cannula. So unless the grafting strategy is altered, the detection of aortic atheroma and the need to move the site of cannulation and clamping is impeded by the inability to move the proximal aortic anastomoses. By performing a composite graft (Y-graft), the aortic anastomoses can be eliminated, thereby allowing the freedom to move sites of aortic manipulation (Royse, Royse et al. 2000; Royse, Royse et al. 1999), see Fig. 2. Should there be extensive aortic atheroma, consideration of "off pump" coronary revascularisation would allow the complete avoidance of any aortic manipulation - the ideal solution from this perspective. Many surgeons however, are not comfortable or skilled in these techniques, thereby limiting their use.

decision to be made that then subsequently leads to the avoidance of embolism. This highlights one of the key difficulties for surgeons. It may be that a surgical alternative is not possible for the patient; or the skill, capability or surgical repertoire of the surgeon themselves limits potential alternative strategies being employed. This may vary with training, experience and technical capability as well as patient factors such as absence of suitable conduits and so forth. Thus there is no commonly applied solution available.

Mild Moderate Severe

In principle however, there are few significant options available for surgical alteration. In the case of the use of cardiopulmonary bypass, aortic calculation and clamping sites may be altered so as to manipulate the aorta near to but not involving the atheroma. Certain operations preclude alteration of manipulation position, and so alternative sites for aortic cannulation or alternatives for aortic clamping need to be considered. In practice, often the surgeon simply accepts the need to manipulate atheromatous segments of the aorta and proceeds anyway. An example may be the performance of an aortic valve replacement; whereby there is very limited scope for alteration of the aortic incision, and it may not be

Coronary artery bypass surgery provides more opportunity to alter the surgical operation so as to avoid atheroma. The construction of proximal aortic anastomoses is predominantly situated in the mid ascending aorta; the proximal aorta is rarely used as this will kink the grafts and the distal ascending aorta is occupied by the aortic clamp and antegrade cannula. So unless the grafting strategy is altered, the detection of aortic atheroma and the need to move the site of cannulation and clamping is impeded by the inability to move the proximal aortic anastomoses. By performing a composite graft (Y-graft), the aortic anastomoses can be eliminated, thereby allowing the freedom to move sites of aortic manipulation (Royse, Royse et al. 2000; Royse, Royse et al. 1999), see Fig. 2. Should there be extensive aortic atheroma, consideration of "off pump" coronary revascularisation would allow the complete avoidance of any aortic manipulation - the ideal solution from this perspective. Many surgeons

however, are not comfortable or skilled in these techniques, thereby limiting their use.

Fig. 1. Ultrasound images of aortic atheroma.

possible to entirely avoid atheroma in this locality.

Fig. 2. Freedom to move sites of aortic manipulation. The sites of aortic manipulation are shown for (A) aorta-coronary and (B) Y graft techniques. Construction of aortic anastomosis limits movement of aortic cannulation and clamp sites away from detected atheroma illustrated in the distal ascending and proximal aortic arch. The atheroma is easily avoided by using the exclusive Y graft technique by moving the sites of cannulation and clamping away from the atheroma. (Small star (\*) is antegrade cardioplegia cannulation site; AV is aortic valve.)

Epiaortic Ultrasound Assessment of the Thoracic Aorta in Cardiac Surgery 41

Fig. 4. Standardised epiaortic echocardiography examination. (Royse and Royse 2006)

Cardio-Thoracic Surgery.

Intraoperative ultrasound examination of the aorta and proximal coronary arteries 10 standard views, 2 supplementary views. LAX, longitudinal axis, SAX, short axis, RCA, right coronary artery, SoV, Sinus of Valsalva, AV, aortic valve, RCC, right coronary cusp of aortic valve, LCC, left coronary cusp, NCC, non coronary cusp, ST Jn, sinotubular junction of aorta, ALMV, anterior leaflet of mitral valve, RV, right ventricle, RVOT, right ventricular outflow tract, MPA, main pulmonary artery, PV, pulmonary valve, LA, left atrium, LAD, left anterior descending artery, Cx, circumflex coronary artery, SVC, superior vena cava, RA, right atrium, RPA, right pulmonary artery, Z1, zone 1 or proximal ascending aorta, Z2, zone 2 or mid ascending, Z3, zone 3 or distal ascending, Z4, zone 4 or proximal aortic arch, Z5, zone 5 or distal aortic arch, RMB, right main bronchus, LMB, left main bronchus, RBCA, right brachiocephalic artery, LCC, left common carotid artery, LSA, left subclavian artery. Reproduced from Royse A and Royse C. A standardised intraoperative ultrasound examination of the aorta and proximal coronary arteries. Interact CardioVasc Thorac Surg 2006;5:701-704. © 2006 European Association of Cardio-Thoracic Surgery with permission from the European Association of

The technique of aortic clamping itself varies, with the repeated application of the aortic clamp rather than the "single clamp" technique; and use of the partial occlusion clamp for the construction of proximal aortic coronary anastomoses, further manipulates the aorta and will lead to greater propensity for dislodgement of any existing aortic atheroma. In particular, the typical Kaye-Lambert partial occlusion ("side biting") clamp will usually occupy the majority of the ascending aorta in a vertical plane and about half of the cross sectional diameter of the aorta in the horizontal plane, see Fig. 3. This clamp will therefore manipulate a considerable part of the ascending aorta even with only one application; and repeated applications would be common.

Fig. 3. Partial occlusion clamp manipulates most of the ascending aorta
