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Complex Aortic Valve Disease in Children

      Aortic valve repair is an accepted option for aortic valve pathologic conditions in children and young adults. Historically, aortic valve repair has been considered for annular dilation, redundant leaflet tissue, and restricted leaflet motion with or without deficient leaflet tissue. Repair has been accomplished by multiple techniques, including annuloplasty, leaflet excision and/or plication, commissurotomy, and pericardial leaflet extension and/or replacement.
      • Duran C.M.
      Aortic valve repair.
      More recently, pericardium has been used with promising results to augment and/or replace one or more of the leaflets in either tricuspid or bicuspid valves.
      • Halees Z.A.
      • Maie Al Shahid M.A.
      • Aly Al Sanei A.A.
      • et al.
      16 years follow-up of aortic valve reconstruction with pericardium: A stentless readily available cheap valve?.
      • Bacha E.A.
      • McElhinney D.B.
      • Guleserian K.J.
      • et al.
      Surgical aortic valvuloplasty in children and adolescents with aortic regurgitation: Acute and intermediate effects on aortic valve function and left ventricular dimensions.
      One can often manage insufficient or stenotic tricuspid or bicuspid aortic valves with one- or two-leaflet repair, minimizing the use of nonautologous tissue; complex unicuspid or severe bicuspid aortic valve disease often requires three-leaflet repair or replacement. Using many of these techniques, one can create a competent bicuspid or tricuspid aortic valve from a severely stenotic or insufficient unicuspid, bicuspid, or tricuspid aortic valve. Precise preoperative imaging with echocardiography is imperative for identification of the valve's pathologic condition and coronary anomalies, which are frequently associated with congenital aortic valve disease.

      Operative Technique

      Figure thumbnail gr1
      Figure 1(A) Following sternotomy, autologous pericardium is harvested, fixed in 0.6% glutaraldehyde for 20 minutes, and rinsed. This fixes but does not stiffen the pericardium and makes it less likely to calcify. Cardiopulmonary bypass is established by ascending aortic and bicaval cannulation. The ascending aorta is examined and, if enlarged, an ascending aortoplasty is considered (see E). Myocardial preservation is achieved by a single-dose antegrade perfusion of the coronary arteries with 20 mL/kg of cold Boston Children's cardioplegia solution. Additional direct coronary ostial cardioplegia solution is delivered if there is significant aortic insufficiency. A left ventricular vent is placed into the left ventricle through the right superior pulmonary vein; systemic moderate hypothermia (25-28°C) is used. The aorta is cross-clamped after ventricular fibrillation. (B) A complete transverse aortotomy is made at least 1 cm above the commissural origins, and ≈1.5 cm above the right coronary artery. (C) A perpendicular incision is made into the noncoronary sinus and stay sutures are placed on the aortic wall above the commissures. This approach provides optimal exposure by triangulating the orifice and aligning the commissures and valve leaflets symmetrically. The right and left proximal coronary arteries are examined for ostial stenosis and intramural coronary segments and, if necessary, ostial debridement or unroofing procedures are performed. RCA = right coronary artery.

      Severe Multi-leaflet Pathologic Conditions in Unicuspid, Bicuspid, and Tricuspid Aortic Valves

      Unicuspid aortic valves are uncommon, with an incidence of 0.02%. Unicuspid aortic valves are often mis-described as severely stenotic bicuspid aortic valves with fused commissures. However, anatomically they are acommissural or unicommissural. The unicommissural valve is characterized by a single developed commissure, most often posterior and rightward, between the non- and left coronary cusps. There is complete fusion, or a “raphe,” between the right-left and right-noncoronary cusps, which are abnormally low. Historically, many of these patients have required intervention in infancy or early childhood and have often needed early valve replacement.
      The earliest attempts at repairing complex multi-leaflet aortic valve pathology has been centered on the creation of a three-leaflet valve by dividing the raphe, leaflet debridement, and leaflet extensions with pericardium (see technique 1; Figure 2, Figure 3, Figure 4, Figure 5). However, due to concerns that pericardial leaflet extensions may fail early, techniques were developed to maximize native leaflet tissue while still constructing a three-leaflet valve. We have utilized the rudimentary right leaflet to augment and increase the height of the left and noncoronary leaflets while replacing the entire right leaflet with autologous gluteraldehyde-treated pericardium (see technique 2; Fig. 6).
      Figure thumbnail gr2
      Figure 2Technique 1—Leaflet Extensions
      Each part of the aortic valve complex is then carefully examined. Each of the leaflet edges is inspected from the aortic root to the free leaflet edges. Extensive calcification, especially down into the aortic root, often makes valve repair less appealing, while extensive fibrous thickening can be resected and/or thinned. Isolated leaflet prolapse or perforations can often be repaired with a simple leaflet plication stitch or autologous pericardial patch-plasty of the leaflet. (A) Examination of the unicuspid valve reveals the classic “toilet seat” appearance and two primitive unsupported thickened raphes. (B) The bicuspid valve has two developed commissures and a single primitive unsupported thickened raphe. (C) The valve commissures and raphes are divided to the aortic wall and extensively debrided and thinned. Division of the raphe allows the maximum effective orifice, minimizing any residual stenosis. (D) Particular attention is paid to the right coronary leaflet, as it is often more extensively thickened and retracted. Extensive debridement allows less chance for residual fibrosis of right coronary leaflet tissue to cause late right coronary ostial stenosis. Furthermore, debridement and shortening of the native right coronary leaflet effectively lengthens the right coronary leaflet, allowing a similar length of pericardium for extension, and providing improved coaptation. (E) After raphe division and sharp debridement, the aortic root and subaortic area can easily be examined. There are frequently thick fibrous subaortic membranes extending onto the aortic leaflets and/or the anterior mitral leaflet that can be pealed off or resected. L = left; LCA = left coronary artery; MV = mitral valve; N = non; R = right; RCA = right coronary artery.
      Figure thumbnail gr3
      Figure 3To support each of the now “free floating” valve leaflets, glutaraldehyde-treated pericardial leaflet extensions will allow fixation of the native leaflet to the aortic wall and create three neo-aortic sinuses. (A) Using a silk tie, precise measurements are taken of each “stretched” leaflet, so as not to foreshorten the pericardial extension, which can lead to stenosis or insufficiency. (B) The heights of the pericardial leaflet extensions are arbitrarily defined by the height of the debrided left coronary leaflet. (C) The treated autologous pericardium is then precisely shaped into rectangular leaflet extensions for the left and noncoronary leaflets, and (D) in a more customized fashion for the right coronary leaflet. L = left; MV = mitral valve; N = non; R = right.
      Figure thumbnail gr4a
      Figure 4(A-C) The right coronary leaflet is often sewn first, since it has been more extensively debrided and requires a more complicated, gentle “U-shaped” pericardial patch. Stay stitches are placed at each commissural base for accurate suturing, as the pericardial extensions often appear too long. Each of the three patches is sewn to the residual leaflet (and occasionally the root) with 5.0 or 6.0 polypropylene suture before creating the commissural base. Particular attention is paid to sewing the leaflet extensions from inside the sinus, as this allows better leaflet coaptation. (D) When each of the sinuses is placed beside the others after a completed repair, one can appreciate the irregularity and height difference of the right leaflet extension. Extensive leaflet debridement can minimize detailed trimming of the pericardial leaflet extensions. However, due to the more extensive debridement required of the rudimentary right coronary leaflet, the right leaflet extension is often more irregular and the height is slightly increased compared with the left and noncoronary pericardial leaflet extensions. (E) The commissures are then created by sewing each of the two leaflets and the aortic wall together upwards toward the new sinotubular junction. (F) Commisuroplasty sutures are then placed, using small pericardial pledgets immediately adjacent to the aortic wall. Larger pledgets diminish effective orifice and can create stenosis. Leaflet length can be slightly shortened with another commisuroplasty stitch if the leaflet length is too long. (G) The completed repair. (H) Primary closure of the noncoronary sinus. (I) The noncoronary sinus is most often closed primarily. However, if there is supravalvar aortic stenosis or the aortic root is particularly small, a triangular-shaped pericardial patch is used to enlarge the noncoronary sinus. Care must be taken not to enlarge this sinus too much, as this changes the root diameter and can significantly alter leaflet coaptation, leading to significant insufficiency. If the ascending aorta is significantly dilated, an ascending aortoplasty is performed (see E). L = left; LCA = left coronary artery; MV = mitral valve; N = non; R = right; RCA = right coronary artery.
      Figure thumbnail gr4b
      Figure 4(A-C) The right coronary leaflet is often sewn first, since it has been more extensively debrided and requires a more complicated, gentle “U-shaped” pericardial patch. Stay stitches are placed at each commissural base for accurate suturing, as the pericardial extensions often appear too long. Each of the three patches is sewn to the residual leaflet (and occasionally the root) with 5.0 or 6.0 polypropylene suture before creating the commissural base. Particular attention is paid to sewing the leaflet extensions from inside the sinus, as this allows better leaflet coaptation. (D) When each of the sinuses is placed beside the others after a completed repair, one can appreciate the irregularity and height difference of the right leaflet extension. Extensive leaflet debridement can minimize detailed trimming of the pericardial leaflet extensions. However, due to the more extensive debridement required of the rudimentary right coronary leaflet, the right leaflet extension is often more irregular and the height is slightly increased compared with the left and noncoronary pericardial leaflet extensions. (E) The commissures are then created by sewing each of the two leaflets and the aortic wall together upwards toward the new sinotubular junction. (F) Commisuroplasty sutures are then placed, using small pericardial pledgets immediately adjacent to the aortic wall. Larger pledgets diminish effective orifice and can create stenosis. Leaflet length can be slightly shortened with another commisuroplasty stitch if the leaflet length is too long. (G) The completed repair. (H) Primary closure of the noncoronary sinus. (I) The noncoronary sinus is most often closed primarily. However, if there is supravalvar aortic stenosis or the aortic root is particularly small, a triangular-shaped pericardial patch is used to enlarge the noncoronary sinus. Care must be taken not to enlarge this sinus too much, as this changes the root diameter and can significantly alter leaflet coaptation, leading to significant insufficiency. If the ascending aorta is significantly dilated, an ascending aortoplasty is performed (see E). L = left; LCA = left coronary artery; MV = mitral valve; N = non; R = right; RCA = right coronary artery.
      Figure thumbnail gr5
      Figure 5The complex unicusp or bicuspid aortic valve can be repaired using either three- (A) or two- (B) leaflet extensions. However, the creation of a three-leaflet valve allows the most effective orifice and minimizes any residual gradient.
      Figure thumbnail gr6a
      Figure 6Technique 2—Complete Right Leaflet Replacement
      Again, each part of the aortic valve complex is examined from the leaflet edges to the aortic root. (A) Examination of the unicusp aortic valve reveals the classic “toilet seat” appearance and two primitive unsupported thickened raphes. The rudimentary right leaflet will be used to augment and increase the heights of the left and noncoronary leaflets. (B) The rudimentary right leaflet is divided between the two raphes (R1 and R2), toward the aortic wall. An incision is carried along the aortic wall toward each raphe, leaving 1 to 2 mm for suturing the pericardium that will form the right leaflet. By turning up the right leaflet, it allows the height of the left and noncoronary leaflets to be extended with native leaflet tissue. The leaflet edges are then debrided. (C) The entire right leaflet is then replaced/created with glutaraldehyde-treated pericardium. To approximate the height of the right leaflet, a silk tie is used to measure the height of the newly created left leaflet, while the length can be approximated from the distance between the two raphes and the free edge lengths of the left and noncoronary leaflets. The new pericardial right leaflet is then sutured to the residual 1- to 2-mm native right leaflet and the aortic wall until reaching the raphes. (D) The left and nonaortic sinuses are then created by suturing the extended left and nonleaflet edges (the portions of the right leaflet cut along the aortic wall are rotated 90°) up the aortic wall at the raphes. The pericardial leaflet edges are similarly attached to the aortic wall at the raphes. (E) Commissures are then created. (F) Note the pericardium replaces the entire right leaflet. A commissural suture may also be placed between the left-noncommissure, as there is often a gap in this location. (G) The completed repair. L = left; LCA = left coronary artery; MV = mitral valve; N = non; R = right; RCA = right coronary artery.
      Figure thumbnail gr6b
      Figure 6Technique 2—Complete Right Leaflet Replacement
      Again, each part of the aortic valve complex is examined from the leaflet edges to the aortic root. (A) Examination of the unicusp aortic valve reveals the classic “toilet seat” appearance and two primitive unsupported thickened raphes. The rudimentary right leaflet will be used to augment and increase the heights of the left and noncoronary leaflets. (B) The rudimentary right leaflet is divided between the two raphes (R1 and R2), toward the aortic wall. An incision is carried along the aortic wall toward each raphe, leaving 1 to 2 mm for suturing the pericardium that will form the right leaflet. By turning up the right leaflet, it allows the height of the left and noncoronary leaflets to be extended with native leaflet tissue. The leaflet edges are then debrided. (C) The entire right leaflet is then replaced/created with glutaraldehyde-treated pericardium. To approximate the height of the right leaflet, a silk tie is used to measure the height of the newly created left leaflet, while the length can be approximated from the distance between the two raphes and the free edge lengths of the left and noncoronary leaflets. The new pericardial right leaflet is then sutured to the residual 1- to 2-mm native right leaflet and the aortic wall until reaching the raphes. (D) The left and nonaortic sinuses are then created by suturing the extended left and nonleaflet edges (the portions of the right leaflet cut along the aortic wall are rotated 90°) up the aortic wall at the raphes. The pericardial leaflet edges are similarly attached to the aortic wall at the raphes. (E) Commissures are then created. (F) Note the pericardium replaces the entire right leaflet. A commissural suture may also be placed between the left-noncommissure, as there is often a gap in this location. (G) The completed repair. L = left; LCA = left coronary artery; MV = mitral valve; N = non; R = right; RCA = right coronary artery.

      Aortic Root, Sinuses, and Ascending Aorta

      There is often associated aortic root and ascending aortic pathology associated with aortic valve disease. Care must be taken when altering the aortic sinuses, as significant changes to the aortic root diameter can significantly alter leaflet coaptation. Also if there is ascending aortic dilation, an aortoplasty should be considered (Fig. 7E).
      Figure thumbnail gr7
      Figure 7(A) An enlarged aortic sinus can cause “stretching” of the leaflet, resulting in poor leaflet mobility, which leads to stenosis and/or insufficiency. (B) A triangular resection of aortic wall from the noncoronary sinus with primary closure will decrease the aortic diameter, resulting in more leaflet mobility, better coaptation, and less stenosis and/or insufficiency. (C) A small aortic root and/or sinus can have the opposite effect where the leaflet “folds or buckles” with resultant insufficiency. (D) The noncoronary sinus is most often closed primarily. However, if there is supravalvar aortic stenosis or the aortic root is particularly small, a triangular-shaped pericardial patch is used to enlarge the noncoronary sinus. Care must be taken not to enlarge this sinus too much, as this changes the root diameter and can significantly alter leaflet coaptation, leading to significant insufficiency. (E) If the ascending aorta is significantly dilated, an ascending aortoplasty is performed.

      Imaging Complex Aortic Valve Disease

      Perioperative imaging using two- and three-dimensional echocardiography provides the surgeon with important specific anatomic details and quantitative measurements under physiologic conditions.
      • Vida V.L.
      • Hoehn R.
      • Larrazabal L.A.
      • et al.
      Usefulness of intra-operative epicardial three-dimensional echocardiography to guide aortic valve repair in children.
      Aortic valve leaflet dimensions and areas can be precisely determined. Any thickened valve leaflet edges causing imperfect coaptation can also be determined. Accurate imaging maximizes the chances of preserving native aortic valve leaflet tissue and reduces the amount of nonnative aortic valve tissue (pericardium) needed for valve repair.

      References

        • Duran C.M.
        Aortic valve repair.
        Asia Pacific J Thorac Cardiovasc Surg. 1994; 3: 64-68
        • Halees Z.A.
        • Maie Al Shahid M.A.
        • Aly Al Sanei A.A.
        • et al.
        16 years follow-up of aortic valve reconstruction with pericardium: A stentless readily available cheap valve?.
        Eur J Cardiothorac Surg. 2005; 28: 200-205
        • Bacha E.A.
        • McElhinney D.B.
        • Guleserian K.J.
        • et al.
        Surgical aortic valvuloplasty in children and adolescents with aortic regurgitation: Acute and intermediate effects on aortic valve function and left ventricular dimensions.
        J Thorac Cardiovasc Surg. 2008; 135: 552-559
        • Vida V.L.
        • Hoehn R.
        • Larrazabal L.A.
        • et al.
        Usefulness of intra-operative epicardial three-dimensional echocardiography to guide aortic valve repair in children.
        Am J Cardiol 2009. 2009; 103: 852-856