1. Repair of Atrioventricular Septal Defects: The 2-Patch Sandwich Technique 
Hagi Dekel, MD, Jiaquan Zhu, MD, John G. Coles, MD 
Operative Techniques in Thoracic and Cardiovascular Surgery 
Volume 20, Issue 1, Pages (March 2015)
DOI: /j.optechstcvs
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2. Figure 1
Rastelli type A. Variations in the morphologic features of AVSDs result mainly from the extent of bridging of the superior leaflet across the plane of the VSD. The most common arrangement present in approximately 80% of cases features separation of the superior leaflets into right and left components with limited bridging of either leaflet across the plane of the VSD. In this arrangement, both left and right components of the superior leaflet are supported by symmetrically disposed marginal chordae that attach to the underlying ventricular septal crest. This morphologic arrangement is referred to as Rastelli type A. Less commonly, a distinctly bridging superior leaflet is present but attenuated in the anteroposterior (AP) dimension such that its length is ~5-8mm, as shown. The other common subtype, referred to as Rastelli type C, features a large superior bridging leaflet with a prominent left-right dimension that overrides both the ventricular chambers in a symmetrical fashion (Fig. 2). The morphology of the posterior bridging leaflet is conserved irrespective of the superior leaflet morphology in that the posterior leaflet invariably exhibits symmetrical bridging across the plane of the VSD. In contrast to the superior bridging leaflet present in Rastelli type C (Fig. 2), the width of the inferior bridging leaflet in its left-right dimension is typically 50% less than that of the superior bridging leaflet. RSL = right superior leaflet; SBL = superior bridging leaflet; LSL = left superior leaflet; RIL = right inferior leaflet; IBL = inferior bridging leaflet; RLL = right lateral leaflet.
Operative Techniques in Thoracic and Cardiovascular Surgery  , 63-74DOI: ( /j.optechstcvs )
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3. Figure 2
Rastelli type C. In approximately 20% of cases, a larger (free-floating) superior leaflet exhibits symmetrical bridging across the plane of the VSD. The attachment of the superior (atrial) aspect of the VSD patch to this leaflet serves to partition the superior bridging leaflet into left and right AV valve components. In this arrangement, the symmetrically disposed chordae supporting the superior bridging leaflet originate from the corresponding ventricular chambers and are not present on the ventricular septal crest; they are thus remote from the VSD patch suture line. This type of superior bridging leaflet anatomy is referred to as Rastelli type C. In this subtype, the marginal chordae supporting the left superior bridging leaflet arise from the anterior papillary in the LV. Regardless of the Rastelli type, the chordae supporting the mural leaflet are characteristically symmetrical such that the chordae to anterior half of the mural leaflet originate from the anterior papillary muscle, whereas the chordae to the posterior half of the mural leaflet originate from the posterior papillary muscle. Regardless of the morphologic arrangement, the first step in planning the repair is to visualize the projected suture line siting on the ventricular septal crest for the VSD patch beneath both the superior and the inferior leaflets (dotted lines). An important tenet of repair is to ensure that septation of the AV valve junction is symmetrical relating to the common orifice; meaning that the line of attachment of the VSD patch to the AV valve leaflets is aligned with the underlying ventricular septal crest. It is important and useful for the surgeon to keep in mind the Rastelli subtype, as this dictates the correct line of attachment to the of the superior (atrial) aspect of the VSD patch, either to the left superior leaflet (in Rastelli type A; Fig. 1) or to the midline of the superior bridging leaflet (in Rastelli type C; Fig. 2). It should be noted that division of the superior (or inferior) bridging leaflet is inadvisable (and in any case unnecessary), as it may lead to a very small but statistically discernible increased risk of early postoperative repair dehiscence.4 In a few cases, division of a single chord if required to improve exposure under either bridging leaflet is permissible, provided it is a secondary chord or is situated in the plane of the leaflet to which the superior margin of VSD patch will be attached. LV = left ventricle; SBL = superior bridging leaflet.
Operative Techniques in Thoracic and Cardiovascular Surgery  , 63-74DOI: ( /j.optechstcvs )
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4. Figure 3
Determination of cleft components. The first step in the repair itself is to define the base of the cleft, more properly referred to as the zone of apposition between the left superior and left inferior leaflets of the future left AV valve. The base of the cleft refers to the contact point between the left inferior and left superior leaflets that also corresponds to the plane of the VSD projected vertically from the ventricular septal crest. The VSD patch is subsequently attached to this point, the identification of which is aided by floating the AV valve leaflets using saline injection into the LV. This point on each leaflet is marked with a 6-0 PROLENE suture that is tied and cut short to avoid inadvertent traction on the leaflets and obstructed vision resulting from otherwise uncut sutures. Identification of the precise base of the cleft is critical, as it determines the length of the cleft following VSD closure (inset). The length of the superior and inferior leaflets contributing to the cleft must be equal to minimize distortion of the left AV valve following closure of the cleft. Leaflet symmetry of the left superior and inferior leaflets comprising the cleft should be confirmed before proceeding with VSD closure. LV = left ventricle; LSL = left superior leaflet; IBL = inferior bridging leaflet.
Operative Techniques in Thoracic and Cardiovascular Surgery  , 63-74DOI: ( /j.optechstcvs )
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5. Figure 4
Anterior portion of VSD suture line. A Dacron patch is tailored for the shape of the VSD such that the height of the patch corresponding to the superior leaflet is greater than that for the inferior leaflet. We recommend designing the height of the patch to ~2-3mm greater than the estimated height of the VSD. As the patch is secured ~ 5-8mm to the rightward margin of the crest of the VSD, the VSD patch should be made ~ 2-5mm less than the distance between the proposed line of attachment of the VSD patch to the ventricular septum and the estimated systolic position of the leaflet margin. This allows more facile manipulation of the patch during suturing without creating leaflet distortion that may otherwise be caused by a greater patch height. In similar fashion, the AP length of the superior margin of the VSD patch is cut to approximately 10% less than the length of the superior leaflet margin of the VSD, which provides a minor reduction annuloplasty effect along the septal portion of the reconstructed annulus. A minimally “undersized” VSD patch is especially advantageous during suturing of the patch to the inferior bridging leaflet in which the chordae may challenge proper siting of the patch to the underlying muscular septal crest. The VSD closure is started toward the anterior (aortic) aspect of the defect and progresses along a line separating the chordae attaching to the medial (septal)-facing portions of the left and right superior leaflets until the transition is made to the atrium.
Operative Techniques in Thoracic and Cardiovascular Surgery  , 63-74DOI: ( /j.optechstcvs )
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6. Figure 5
Posterior margin of VSD suture line. The other limb of the suture is then continued posteriorly, creating a suture line that is 5-8mm rightward to the precise crest of the VSD. To avoid heart block, the suture line at the inferior margin of the VSD and in the inferior bridging leaflet itself deviates 5-8mm rightward of the crux. The crux is defined as the junction point between the AV valve annulus and the margin of the primum atrial defect and is the most reliable and invariant method to identify the location of the AV node. A useful maneuver to ensure precise closure of the posteroinferior portion of the VSD is to stabilize the posteroinferior part of the VSD patch in the AP plane using a 5-0 silk suture attached to a snap. The chordal attachments of the rightward part of the inferior bridging leaflet can be retracted by the assistant, thereby improving exposure of the ventricular septum in the most extreme posteroinferior region of the defect. To further improve exposure so that the exact junction of the muscular septum with the ventricular aspect of the AV valve can be visualized (to prevent residual VSD), the surgeon retracts the inferior bridging leaflet with his or her left hand, while the assistant gently retracts on the patch with his or her right hand (using the patch as a retractor) and retracts the right lateral AV valve leaflet with a small right angle retractor with his or her left hand. To optimize exposure (which may be difficult in this area), it is not necessary for the assistant to “follow the suture” while the operating surgeon actually inserts the suture needle for this region of the repair, but rather he or she should concentrate on providing exposure. IBL = inferior bridging leaflet.
Operative Techniques in Thoracic and Cardiovascular Surgery  , 63-74DOI: ( /j.optechstcvs )
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7. Figure 6
Attachment of the superior margin of a VSD patch to the AV valve leaflets, Rastelli type A. Interrupted horizontal mattress sutures are used to secure the superior (atrial-ward) margin of the VSD patch to the AV valve leaflets in the midseptal plane. In Rastelli type A defects, the suture line attaches the VSD patch to the medial facing edge of the left superior bridging leaflet, as shown. The medial facing edge of the right superior bridging leaflet is later attached to the superior margin of the VSD patch during repair of the right AV valve, as described later (Fig. 9). Regardless of the Rastelli subtype, the needle is passed through the VSD, then the superior leaflet, and finally through a tailored patch of autologous pericardium (smooth side leftward facing); thus creating a secure “sandwich” repair of the AV valve leaflets (inset). The VSD suture line is performed to septate the AV valve inflows into equal sizes, although the right AV orifice is reduced slightly as the suture line deviates rightward as the crux is approached at the posteroinferior margin of the VSD (Fig. 4). As this suture line progresses, proportionate spacing of the bites through leaflet tissue and superior margin of the VSD patch is maintained. The term “proportionate” and not “equal” is appropriate, as the length of leaflet tissue ideally exceeds that of the corresponding VSD patch by ~10%, because the superior margin of the VSD patch is undersized in the AP dimension relative to that of the leaflets. This leaflet-gathering effect serves to reduce tension across the reconstructed leaflets following cleft closure. In Rastelli type C defects, the VSD suture line subdivides the superior bridging leaflet into equal left and right components (Fig. 2). RSL = right superior leaflet; LSL = left superior leaflet; RIL = right inferior leaflet; IBL = inferior bridging leaflet; RLL = right lateral leaflet.
Operative Techniques in Thoracic and Cardiovascular Surgery  , 63-74DOI: ( /j.optechstcvs )
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8. Figure 7
Cleft closure. After completing the suture line that septates the AV valves, the cleft in the left AV valve is closed with multiple interrupted 6-0 PROLENE sutures over its entire length. Closely spaced LV papillary muscles, which are reliably detected on preoperative echo studies, may mandate only partial cleft closure in proportion to the degree of evident “parachuting.” Saline injection into the LV is performed following cleft closure. Typically, there is evidence of mild-minus to mild-plus degrees of central regurgitation. Accordingly, in most cases, we proceed with an annular reduction suture centered over the mural leaflet suture, in which the 2 ends of 5-0 or 6-0 PROLENE sutures are placed in an overlapping fashion designed to reduce the annular diameter by 2-3mm. The extent of annuloplasty is calibrated by repeated saline testing and measurement of postrepair annular diameter, targeting 1-2mm less than that predicted based on BSA. LV = left ventricle; BSA = bovine serum albumin; ML = mural lateral leaflet.
Operative Techniques in Thoracic and Cardiovascular Surgery  , 63-74DOI: ( /j.optechstcvs )
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9. Figure 8
Closure of atrial primum defect. The primum atrial defect is closed using continuous suture technique, leaving the coronary sinus to drain into the right atrium. The siting of the atrial suture line relative to the coronary sinus and AV node is shown by the dotted lines in Figures 1 and 5. The inferior margin of the primum defect should not be circumscribed by sutures used to attach the pericardial patch in the region of the coronary sinus to avoid damage to convergent atrial conduction bundles in this area. IBL = inferior bridging leaflet.
Operative Techniques in Thoracic and Cardiovascular Surgery  , 63-74DOI: ( /j.optechstcvs )
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10. Figure 9
Right AV valve repair. Following closure of the primum atrial defect, evaluation of the competency and caliber of the right AV valve is required. Approximately 50% of cases in our experience exhibit at least a mild-plus degree of right AV valve regurgitation typically emanating from the septal aspect of the valve. This can be addressed by using methods designed for repair of tricuspid valve insufficiency following standard VSD closure. In Rastelli type A, the right superior leaflet is attached to the septum with interrupted pericardial-pledgeted sutures, if necessary, supplemented with a single leaflet-to-leaflet repair between the right superior and inferior leaflets. The latter suture has the effect of bringing the superior and the inferior components of the right AV valve into apposition, analogous to cleft closure of the left AV valve. The remainder of the repair including deairing is performed as usual for the intracardiac repair of congenital heart lesions. RSL = right superior leaflet; LSL = left superior leaflet; RIL = right inferior leaflet; IBL = inferior bridging leaflet; RLL = right lateral leaflet; ML = mural lateral leaflet.
Operative Techniques in Thoracic and Cardiovascular Surgery  , 63-74DOI: ( /j.optechstcvs )
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11. Figure 10
Repair of a transitional AVSD. An AVSD with separate AV valve orifices with a coexisting VSD defines the transitional subtype of AVSDs. Here, the VSD is often restrictive because of excess valvelike tissue causing partial occlusion of the VSD. This excess tissue likely represents a specialized form of endocardial-mesenchymal transition in response to flow turbulence across the defect. This arrangement often occurs in association with an intact atrial septum. In these cases, it may be preferable to modify the standard repair, as visualization of the margins of the defect required for standard repair is difficult, as is safe resection of the excess tissue with preservation of intact chordal anatomy. Instead, repair may be performed by direct suturing of the AV valve leaflets to the rightward aspect of the ventricular septal crest using interrupted, pericardial, pledget-supported sutures after the method described by Karl et al.5 With this anatomical arrangement, it is important to accurately circumscribe the margins of the usually multiple interventricular communications by incorporating the reduplicated, excess valve tissue with the suture placement. It is important to place the sutures through the leaflet tissue of the right AV valve and not the annulus, which may harbor the conduction tissue. If the atrial septum is intact, there is a naturally occurring partial fusion of the base (septal aspect) of the cleft, preempting the need for decisions regarding optimal appositional surfaces of the superior and inferior components of the left AV valve. The remaining open portion of the cleft is closed, as described for the standard repair. Ao = aorta; SVC = superior vena cava.
Operative Techniques in Thoracic and Cardiovascular Surgery  , 63-74DOI: ( /j.optechstcvs )
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