Keywords
mitral valve, mitral valve replacement
Step 1
Anatomy
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The mitral valve is a complex structure comprised of an anterior and posterior leaflet that is connected to the left ventricle via attachments to papillary muscles through the chordae tendineae.
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It is anchored to the mitral annulus, which is in close relation to the circumflex coronary artery laterally, coronary sinus medially, and aortic valve anteriorly.
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Shown in Fig. 19.1 is the mitral annulus in a lateral view, along with view of the mitral valve from the top of the heart showing its proximity to the aortic and tricuspid valves.
Figure 19.1
Step 2
Access to the Mitral Valve
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Exposure of the mitral valve must be optimized to facilitate efficient and effective surgery. Although not described in detail, complete drainage of the right atrium must be achieved prior to arresting the heart and opening the left atrium.
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Left atriotomy via Sondergaard’s groove: The interatrial plane is dissected to separate a portion of the right atrium that overhangs the left atrium toward the septum. This incision is extended superiorly toward the left atrial roof. It is extended inferiorly anterior to the inferior pulmonary veins, but posterior to the inferior vena cava ( Fig. 19.2 ).
Figure 19.2
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Extended vertical transseptal biatriotomy: The right atrium is opened from the right atrial appendage toward the inferior vena cava. The interatrial septum is then incised down to the fossa ovalis and extended cephalad onto the dome of the left atrium. This approach is particularly useful in the setting of reoperative valve surgery with an aortic valve prosthesis in place ( Fig. 19.3 ).
Figure 19.3
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Khonsari biatriotomy: This extends from the right atrial appendage toward the right superior pulmonary vein to expose the interatrial septum, which is then incised transversely through the fossa ovalis ( Fig. 19.4 ).
Figure 19.4
Step 3
Suture Placement for Mitral Valve Replacement
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Continuous suture: This approach to anchoring a prosthesis is typically performed when the mitral annulus is tough and fibrous without much annular calcification. The major advantage of this technique relates to surgical speed, which may be advantageous in robotic or minimally invasive mitral surgery. This is performed with a 3-0 Prolene or Gore-Tex sutures ( Fig. 19.5 ).
Figure 19.5
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Interrupted sutures without pledgets: This technique is performed in the setting of mitral annular calcification or following failed prosthesis removal at the time of reoperative mitral replacement. The major advantage of this technique is that the sewing cuff of the mitral prosthesis will be seated precisely within the plane of the mitral annulus, without any distortion. This is performed with 3-0 Ethibond sutures ( Fig. 19.6 ).
