Search

Composite valve graft implantation described by Bentall and De Bono is a well-documented technique of aortic root replacement used for a large spectrum of pathologic conditions involving the aortic valve and the ascending aorta. While mechanical valves were initially used, biological prostheses were later introduced in order to avoid long-term anticoagulation and its related complications. The increasing age of patients who undergo aortic root surgery, and data supporting the use of a biological aortic valve in the younger population, have significantly increased the need for a composite biological valved conduit. However, parallel to the increased use of biological valve in the context of a Bentall operation, aortic valve-sparing (AVS) operation have also been performed in a growing number of patients. Sarsam and David described the remodeling and the reimplantation procedures more than 25 years ago with the aim of sparing otherwise normal aortic valves in the presence of a root aneurysm. Important achievements in this discipline have occurred over the past decade including development and refinement of valve preserving aortic root replacement techniques, development of a classification system for aortic insufficiency, surgical approaches to cusp disease with different cusp anatomy. Both procedures can now provide excellent root reconstruction and adequate clinical results in terms of late valve durability. The AVS technique offers several advantages over the Bentall procedure, such as no need for oral anticoagulation and lifestyle adjustments. AVS operations have become established alternatives to Bentall procedures for patients with aortic root pathology. However, data comparing the safety and durability of these approaches are lacking.

Aortic valve sparing procedures became more popular in the last decades due to the better understanding of aortic root physiology. Searching for an optimal root reconstruction several modifications have been proposed to the original reimplantation (David) and to the remodeling (Yacoub) technique. Currently, the most adopted technique worldwide is the reimplantation because of its peculiar characteristics of annular stabilization, support of the aortic wall, and better hemostatic efficacy. The remodeling technique aims for optimal root restoration, but does not prevent annular dilatation and may be associated with a higher risk of bleeding. The main theoretical issue with the classic reimplantation operation is the elimination of Valsalva’s sinuses which play a fundamental role in regulating leaflet dynamics. On the other hand, data on long-term aortic valve performance in classic reimplantation procedures without sinuses appears to hold well the test of time. However, over the time this technique has been often modified attempting to re-create sinuses, it is therefore difficult to draw definite conclusions. In the last decade, the use of “anatomic” Dacron graft designed specifically for root reconstruction or specific modifications to the straight Dacron graft, led to a standardization of the technique and consequently to a stable improvement of the results and to the diffusion of the reimplantation. However, long-term durability of the spared valve assessed by the incidence of residual aortic valve insufficiency and/or the need for reoperation during the follow-up is still to be clarified. Overall, the results are satisfactory especially in consideration of the relatively “young age” of this technique. A spared aortic valve with moderate valve regurgitation and/or eccentric aortic jet soon after the procedure, will invariably lead to a later need for reoperation. Therefore, a good coaptation height inside a repaired root warrant long-lasting results.

Valve-sparing aortic root replacement (VSRR) with reimplantation technique is an effective alternative for young patients with dilated roots and preserved cusps, which avoids the risks of lifelong anticoagulation or valve degeneration. New grafts with anatomically-shaped sinuses have been developed in order to preserve aortic root physiology, which could decrease complication rates and improve durability. However, controversy remains regarding the effect of recreation of the sinuses of Valsalva during VSRR on long-term outcomes. The novel 4D flow technique, exploiting its unique ability to combine anatomical evaluation of the root with fluid-dynamic assessment of aortic flow, enables integrated analysis of the close interaction between graft design, valvular morphology and three-dimensional (3D) flow characteristics. Early experimental studies have shown how graft shape affects the aortic root flow pattern, formation of vortexes and helicity of downstream flow; however, the clinical significance of these findings is yet to be clarified. Various and still unexplored knowledge can be obtained from the qualitative and quantitative analysis of these complex datasets, that could shed more light on which is the best among myriad surgical techniques and grafts adopted in VSRR. The extraordinary potential 4D flow imaging opens new boundless horizons in the perspective of an increasingly patient-tailored surgical planning.