How to perform VSRRR in patients with TAAAD?
There are several options for VSRRR in TAAAD including remodelling, remodelling with subannular ring, and reimplantation Some of the technical aspects of the operation are shared among the three alternatives with the differences being primarily in how the root is reconstructed. In the remodelling procedure the graft is fashioned into three tongues that are sutured to the remnants of the aortic root with subannular stabilisation that can be added with a external ring annuloplasty. In the reimplantation procedure the remnant tissue of the native aortic root and the valve are telescoped inside the graft with subannular anchoring of the graft.
In general cardiopulmonary bypass (CPB) is established, in our institution was use the axillary artery and the right atrium. At target temperature, circulatory arrest is established and the arch is reconstructed with an aggressive hemiarch replacement unless the arch is >4.5 cm in diameter. Following arch reconstruction, attention is paid to the aortic root and an initial inspection of the valve is carried out. If there is obvious degeneration or abnormalities that preclude VSRRR then valve preservation is abandoned. Otherwise the aortic sinuses are excised leaving 4-5 mm of root tissue. The commissures are suspended using 4/0 Polypropylene sutures that are put under radial tension. Subsequently the valve is inspected carefully for fenestration, evidence of prolapse, degeneration, or cup retraction. We measure the three cusps from the nadir to the centre of the free margin and the formula 2*[Hcusp*2/3]+8 to 10 is used to choose the graft size. The root is subsequently dissected to the nadir of the cusps with the anatomical limitation in mind. Six 2/0 Polyester sutures are placed in the subannular plane at the commissures and the nadir of each cusp, except at the non-coronary/right coronary cup commissure where the suture is placed externally. The valve is telescoped inside the graft and the graft is anchored to the 2-0 Polyester sutures, which are then secured. We visually determine optimal height of commissural implantation based on the appearance of the valve, water-test and suction test on the cusps. Once the optimal commissural height is determined the aortic root rim is sutured to the inside of the graft starting at the nadir using 5/0 Polypropylene sutures. Afterward, we assess the valve and determine if any leaflet repair is required. Prolapse is corrected either by adjustment of the commissural height or central plication of the leaflets. If the repair is deemed satisfactory the aortic root prosthesis is sutures to the distal Dacron graft and the operation is conducted as usual. We give cardioplegia into the root and assess for evidence of regurgitation by means of manual root pressure and volume returned through the right superior pulmonary vein vent prior to releasing the aortic cross clamp. TEE is evaluated for evidence of AI after releasing the cross clamp prior to discontinuing CPB.
TEE is evaluated after weaning from CPB for evidence of AI. If AI is detected the AI jet degree, direction, cusps motions and gradient across the valve are assessed to determined if re-clamping is needed and plan additional repair of the cusps. Our strategy is to re-clamp if there is evidence of more than 1+ AI.