Learning From Controversy: Contemporary Surgical Management of Aortic Valve Endocarditis

Abstract

Aortic valve replacement is the commonest cardiac surgical operation performed worldwide for infective endocarditis (IE). Long-term durability and avoidance of infection relapse are goals of the procedure. However, no detailed guidelines on prosthesis selection and surgical strategies guided by the comprehensive evaluation of the extension of the infection and its microbiological characteristics, clinical profile of the patient, and risk of infection recurrence are currently available. Conventional mechanical or stented xenografts are the preferred choice for localized aortic infection. However, in cases of complex IE with the involvement of the root or the aortomitral continuity, the use of homograft is suggested according to the surgeon and center experience. Homograft use should be counterbalanced against the risk of structural degeneration. Prosthetic bioroot or prosthetic valved conduit (mechanical and bioprosthetic) are also potentially suitable alternatives. Further development of preservation techniques enabling longer durability of allogenic substitutes is required. We evaluate the current evidence for the use of valve substitutes in aortic valve endocarditis and propose an evidence-based algorithm to guide the choice of therapy. We performed a systemic review to clarify the contemporary surgical management of aortic valve endocarditis.

Commentary: We should not forget the aortic valve allograft

“…In contrast, we certainly agree with the authors that, from the technical aspect, the soft and pliable tissues of the allograft facilitate a perfect anatomical reconstruction of the aortic root, minimize the need of using external foreign material support such as Teflon felts or pericardial strips, and provide better hemodynamic characteristics and laminar flow when compared with other replacement devices, all of which are strong arguments in favor of the aortic root allograft replacement. 1 We also concur with the authors that the aortic valve allograft should not be abandoned and, when performed in experienced centers, is a valuable alternative not only in patients with endocarditis but also in cases with small aortic roots, complex redo scenarios, and in some younger patients who may not be candidates for a Ross operation and have contraindications or are not willing to be in permanent anticoagulation (Figure 1). 1,3 The ability to perform aortic root replacement with similar results compared with conventional aortic valve replacement coupled with newer tissue-processing technologies such as decellularization that may improve long-term allograft durability may renew the interest for broader indications of the aortic allograft.…”

“…1 We also concur with the authors that the aortic valve allograft should not be abandoned and, when performed in experienced centers, is a valuable alternative not only in patients with endocarditis but also in cases with small aortic roots, complex redo scenarios, and in some younger patients who may not be candidates for a Ross operation and have contraindications or are not willing to be in permanent anticoagulation (Figure 1). 1,3 The ability to perform aortic root replacement with similar results compared with conventional aortic valve replacement coupled with newer tissue-processing technologies such as decellularization that may improve long-term allograft durability may renew the interest for broader indications of the aortic allograft. 7,8 However, this will need to be supported by strong scientific data, such as those provided by Witten and colleagues.…”

“…4,5 In most of these studies, however, it becomes apparent that patients with complex destructive root anatomies, prosthetic valve endocarditis, and infections caused by resistant fungi or bacteria tended to be more often treated with an allograft root replacement. 1 Unfortunately, the study by Witten and colleagues, 6 by not including a control group of patients operated with conventional prosthetic valves, does not allow us to make any inference regarding the alleged allograft superior resistance to infection. In that sense, the institutional philosophy to treat noninvasive cases with conventional stented prosthesis and reserve allografts mainly for cases with more advanced root destruction may be considered somewhat empirical and intuitive but still lacks rigorous scientific confirmation and supportive data.…”

“…Short-and long-term outcomes of surgical treatment of patients with active aortic valve bacterial endocarditis are influenced by multiple factors, including microbiology, patient-related factors, optimal perioperative care, timing of intervention, meticulous surgical techniques, and eventually by the type of the replacement device. 1 Previous studies have suggested that aortic valve allografts were associated with lower rates of early and late reinfections, and, as a consequence, became the valve of choice for treating active aortic valve infections in many centers. 2 More recently, however, this concept has been challenged, and several reports failed to demonstrate that prosthesis type has significant impact on patient survival and reinfection rates.…”

A 20-year experience with cryopreserved allografts as the valve replacement of choice in aortic root reconstruction for destructive endocarditis with abscess formation

“…Second, their superior haemodynamics, presumed bacterial resistance, low incidence of reinfection, the avoidance of warfarin-related complications and very low thrombotic event rates. Thus, all these advantages make the allograft an ideal substitute with good clinical outcomes [ 14–16 ].…”