Aortic Valve Sparing Root Replacement Versus Bentall

Overview

This study was designed to evaluate the hypothesis that the operative and midterm results of valve-sparing aortic root replacement are equivalent to those of the Bentall. Objective 1: Evaluate short-term (one-to-six months) and mid-term (six-to-forty-eight months) results of aortic valve-sparing procedures. Objective 2: Compare the results of aortic valve-sparing procedures with the group of patients undergoing Bentall procedures during the same period. Objective 3: Assess outcomes of both procedures through evaluation of postoperative: A) primary outcome measures: 1. Intraoperative or intrahospital death. 2. Reexploration for bleeding. 3. Reoperation rate. 4. Grade of aortic valve regurgitation (0-4). B)secondary outcome measures: 1. Grade of aortic valve regurgitation (0-4). 2. Mean gradient on the aortic valve(mmHg). 3. Thromboembolism / bleeding. 4. Prosthetic/native valve endocarditis. 5. 2-year mortality

The aortic root is a complex structure whose single components are of paramount importance in assuring proper functioning of the aortic valve. In fact, opening and closing behaviors of the aortic leaflets are regulated by the interaction of the various components of the aortic root as well as by the characteristics of blood flow. Operation was the only possible surgical solution for diseases involving the sinuses of Valsalva and the aortic valve. Even in experienced hands, the perioperative mortality was not insignificant. However, since the introduction of the exclusion technique, the mortality and major morbidity of aortic root replacement have seen a dramatic decline. In recent years, groups focused on aortic disease have reported elective operative mortality less than 5%, with a marked decline in the incidence of stroke, hemorrhage, and other major postoperative complications. The composite graft replacement, as originally reported by Bentall and De Bono in 1968, has become a milestone in proximal aortic surgery, by providing the solution to a surgical problem that was a formidable challenge for that era. From the original report, many relevant scientific papers continued to address both the disease (dilatation or dissection of the proximal aorta, involving the aortic root and, often, the aortic valve) and its surgical correction. This ongoing attention led to several major refinements of the original technique and to the development of improved prosthetic material. All these efforts were aimed at the solution of two major problems affecting the original inclusion-wrapping technique: pseudoaneurysm formation (usually at the site of coronary anastomosis) and transprosthetic bleeding due to excessive porosity of the vascular prosthesis. For many years, however, little attention was paid to the fact that, in many instances, the aortic valve was intrinsically healthy, and nonetheless was substituted, thus unnecessarily exposing the patient to the risk of valve-related complications. The analysis of the normal anatomy and physiology of aortic root is the basis for establishing the surgical transition, in selected cases, from aortic root replacement to aortic valve-sparing operation. In 1983, however, Dr Yacoub addressed the issue of aortic insufficiency secondary to dilatation of the sinotubular junction and he proposed to resect the entire diseased aortic wall, preserving the valve with its commissural posts. A properly tailored vascular prosthesis, with three semicircular tongues, was then sutured to a small rim of the aortic wall just above the aortic annulus, following its three-cusp, crown-shaped line. The entire aortic root was therefore remodelled, thus justifying the appellation of remodelling technique, with reconstruction of a bulged root and a well defined sinotubular junction. Approximately 10 years later, Dr David introduced the aortic valve-sparing reimplantation technique by means of which the valve remnants prepared in a similar manner were reimplanted inside a cylindrical Dacron conduit. The introduction of techniques for valve-sparing aortic root replacement over 20 years ago has allowed for the preservation of healthy aortic valve in patients with severely diseased aortic roots. Moreover, an attempt is made to reconstruct as closely as possible all anatomic components of the aortic root, thus restoring the physiologic behaviour of the aortic valve leaflets within the reshaped root. By maintaining native aortic valve function, potential adverse events related to the use of either a mechanical or a bioprosthetic valve are avoided, including eliminating the lifelong burden of anticoagulation or the risk of structural valve deterioration. As such, valve-sparing aortic root replacement is an attractive therapy for aortic root pathology with preservation of the native aortic valve. Limited data exist comparing valve-sparing aortic root replacement and conventional aortic root replacement with a composite valve-conduit. Furthermore, these studies are limited by small patient numbers, selection bias.