Bicuspid aortic valve repair: the 180°-Reimplantation technique

Abstract

Bicuspid aortic valves (BAVs) represent a wide spectrum of aortic valve phenotypes. We have therefore previously proposed a new repair-oriented surgical classification for BAVs in order to facilitate our understanding of any given phenotype and to guide surgical repair. BAVs can range from symmetric to very asymmetric, and classification is determined by commissural orientation. This can therefore range from 180° to 120° respectively, and as such has further implications for the presence or absence of a raphe; the height of the non-functional commissure (raphe); the length of the line of cusp fusion; and the architecture of the aortic valve sinuses. Over the last three decades, we have attempted different repair strategies for BAVs, with its respective learning curves and have achieved the best long-term repair results with our signature approach: the 180°-Reimplantation technique (El Khoury technique). Although very asymmetric and tricuspid aortic valve-like phenotypes are sometimes best repaired through tricuspidization, we have found that the majority of BAVs are amenable to our 180°-Reimplantation technique. This technique creates a symmetric valve, through a selective annuloplasty, and stabilization of the entire functional aortic annulus (FAA) with reimplantation of the commissure at 180° at the level of the virtual basal ring (VBR) and sinotubular junction (STJ). Depending on the valve phenotype, additional cusp modifications are often required to address one or two prolapsing cusps and/or a fibrous raphe. With this, we have previously reported a 12-year survival rate of 94%, which is alike the general population, and also an overall freedom from aortic valve reoperation of 91%.

Keywords: Bicuspid aortic valve (BAV); aortic annuloplasty; aortic valve regurgitation; reimplantation technique; valve-sparing root replacement.

Figure 1

Repair-oriented surgical classification for BAVs. symmetric-, asymmetric- and very asymmetric phenotype, based on commissural orientation (180°–120°). Upper panel: Raphe height; middle panel: length of cusp fusion and valve morphology; lower panel: Commissural orientation. BAV, bicuspid aortic valve.

Figure 2

Surgical exposure of the aortic root. The anterior wall of the ascending aorta is carefully suspended to the skin with a 4.0 Prolene suture. The commissures and the raphe are each suspended with a separate 4.0 Prolene suture tagged to a mosquito- or hemostat-clamp. The LCA remains attached to the distal aorta, until reimplantation into the Valsalva-graft later. Aortic root dissection. We typically perform our aortic root dissection in the following order: (I) non-coronary sinus dissection, with resection of the aortic sinus tissue leaving a 3–4 mm aortic remnant. Dissection underneath the sinus from outside of the aortic root, to reach the level of the VBR; (II) mobilization of the right coronary button; (III) followed by mobilization of the left coronary button. The left coronary button is left attached to the ascending aorta. LCA, left coronary artery; VBR, virtual basal ring.

Figure 3

El Khoury maneuver—360° aortic root dissection. This is a key maneuver of our reimplantation technique. Following the initial dissection of the aortic root with mobilization of coronary buttons, the RVOT is lifted from LVOT. The RVOT is essentially rolled away from the LVOT, thereby exposing the interventricular septum, and lifting the aortic valve out of the heart. This dissection enables the surgeon to place the Valsalva-graft at the level of the VBR from outside of the LVOT. This is critical in-order-to achieve an annuloplasty at the correct level. Care must be taken not to injure the membranous septum at the right/non-commissure. Here the dissection stops once the fibrous fibers of the membranous septum are identified. RVOT, right ventricular outflow tract; LVOT, left ventricular outflow tract; VBR, virtual basal ring.

Figure 4

Sizing of the Valsalva-graft. To size the graft, a straight line is drawn with a blue marking pen from the nadir of the non-coronary cusp to the nadir of the left-coronary cusp. This line also represents the VBR. Another short line is then drawn at the tip of the non/left-commissure. The distance between these two lines, determines the height of the commissure and the size of the graft. In this drawing, a 28 mm Valsalva-graft. VBR, virtual basal ring.

Figure 5

Placement of basal ring sutures. The bespoke number of subvalvular sutures is determined by valve-morphology. In this case, the valve is asymmetric at 140° commissural orientation. Thus, there is asymmetry of the valve sinuses. In this case one pledgetted horizontal mattress suture (2.0 Ticron) is placed at each commissure. Five additional sutures are placed under the fused cusp sinus, two before the raphe, one at the raphe and two after the raphe. three to four additional sutures are placed under the non-fused cusp sinus, depending on the size of the sinus. These sutures also form the first hemostatic suture line.

Figure 6

Basal ring sutures. The basal ring sutures are all placed at the level of the VBR. Hence, on one line. There is no scalloping, except for the area of the membranous septum at the right/non-commissure. Here the sutures are placed closer to the cusp insertion, to avoid accidental injury to the conduction system. Hence, one suture before the commissure, one at the commissure and one following the commissure are placed higher. RC, right-coronary cusp; NC, non-coronary cusp; LC, left-coronary cusp; VBR, virtual basal ring.

Figure 7

Selective annuloplasty. The asymmetry of the aortic valve sinuses mandates placement of a tailored number of subvalvular sutures, to achieve two symmetric sinuses after the Valsalva-graft is placed. With this, the free margin length of the fused cusp is relatively increased, which allows for tension free completion of the line of cusp fusion and repair of the fused cusp prolapse. It also relatively increases the aortic valve orifice area, which is covered by the more mobile and normal non-fused cusp, which in itself, will improve the transvalvular gradient. (A) Placement of subvalvular sutures; (B) same valve: placement in the Valsalva-graft, which completes the annuloplasty, with creation of a symmetric valve and symmetric FAA. FAA, functional aortic annulus.

Figure 8

Mobilization of the raphe. Fused cusp mobility is generally impaired due to a restrictive non-functional commissure or fibrotic raphe. To improve fused cusp mobility, the raphe is detached from the aortic wall. However, there is variability in commissural height and cusp insertion. Hence, in-order-to avoid perforation of the cusp, it is important to evaluate cusp insertion first, as this will determine the amount of raphe mobilization. To further improve cusp mobility, we will additionally thin a fibrous raphe with an 11-blade or sharp scissors.

Video 1

Bicuspid aortic valve repair: the 180°-Reimplantation technique.

Figure 9

Central cusp plication. To treat a cusp prolapse and complete the line of cusp fusion, a central plication is performed with a 4.0 Prolene suture. This is, depending on the quality of cusp tissues, either a 5.0 or 6.0 Prolene suture. This is a simple suture, which shortens the free margin length and is often reinforced with another figure-of-8 stitch. The non-fused cusp is also evaluated for a prolapse and treated in a similar fashion, if needed.

Figure 10

Valsalva-graft preparation. The Valsalva-graft is prepared in the following fashion: it’s transected distally and left as long as needed to accommodate a concomitant ascending aorta replacement. The lower skirt is completely removed. With a marking pen, the second commissure is marked with a long line at 180°, and the raphe is marked with a short line at 90°. Typically, at the second commissure, we will also mark the elevation of the first suture line at the bottom of the Valsalva portion to accommodate the three sutures, which are placed closer to the cusp insertion in the area of the membranous septum. Hence, in this area the sutures are not only placed higher in the aortic annulus, but this is also mirrored in the higher placement on the Valsalva-graft as well.

Figure 11

Commissural reimplantation at the level of the neo-STJ. The commissures are reimplanted at 180° at the level of the neo-STJ. This is done with a horizontal mattress 4.0 Prolene suture. The commissures are placed as high as possible, keeping an eye on the valve free margins to assess for valve prolapse or cusp restriction. The commissures can be readjusted to achieve ideal placement. The sutures are then tied and tagged to a rubber-shod mosquito. STJ, sinotubular junction.

Figure 12

Dynamic saline test. A dynamic saline test is performed with a Tumi syringe. The graft is pressurized with cold normal saline, which allows for assessment of the cusps thereafter. This allows for evaluation of the valve for possible residual prolapse, which can then be addressed immediately.