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Aortic Valve Repair
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The reimplantation technique is used whenever the root size is greater than 40mm or
anytime one of the goals of repair is to improve the valve symmetry regardless of the root
dimensions. Effectively, in case of regurgitation, we believe that it is easier and favorable for
repair durability to re-implant the valve in a symmetric configuration (commissure orientation
of 180°) (Figure 25). Arguably the symmetric configuration allows a laminar blood flow
across the valve which in turn might enhance repair durability compared to a turbulent flow
across an asymmetric valve. Furthermore, as we have already seen, the circumferential
annuloplasty of VSRR allows an easier management of the raphe, especially in cases of
restrictive type 1 BAV. VSRR allows indeed direct re-approximation of the leaflet after raphe
resection and improve cusp mobility.
Valve symmetry nonetheless involves 3 levels: the VAJ, the commissures and the
sinuses. Therefore, we perform a “symmetric annuloplasty” at the VAJ level that consists in
distributing the proximal suture line stitches evenly onto the graft between the conjoined and
non-conjoined cusps. although the portion of VAJ corresponding to the conjoined cusp
accounts generally for more than 180° of root circumference (Figure 23). To complete valve
symmetry, the two commissures are reimplanted at 180° inside the graft up.
In our experience, we have employed VSRR-reimplantation plus cusp repair for the vast
majority (80%) of patients with BAV disease amenable to repair. During this procedure, the
valve is kept symmetric in cases of Type 0 morphology, and is made symmetric in Type 1
morphologies unless the valve was very asymmetric with <140° commissures orientation. In
this case indeed, the valve may be best transformed into a tricuspid valve by commissural
reconstruction as already described.
RESULTS OF AORTIC VALVE REPAIR
Repair of the aortic valve should supposedly allow patients requiring surgery for aortic
dilatation or valve regurgitation to avoid the risks of prosthesis-related complications,
whether xenograft or mechanical prosthesis, mainly structural valve deterioration and
reintervention, infective endocarditis, anticoagulation-related bleeding or thromboembolic
events, and ultimately mortality. Valve replacement with the pulmonary autograft, the Ross
operation, provides excellent results but in face of the technical complexity it should be
reserved mainly for patients with AV stenosis. Nonetheless, results of AV repair should be
first divided by indication for surgery, that means the mechanism of AR in our classification
(Figure 6). Therefore, in the next paragraphs we’ll discuss the results of AV sparing/repair in
cases of aortic dilatation (Type I), cusp prolapse (type II) or cusp restriction (type III).
However, we should not forget that more mechanisms of AR can coexist in any given patient
and oftentimes the available series report the results of different techniques implemented
together (e.g., valve sparing root replacement plus cusp repair) for one indication or the
results of one technique (e.g., cusp repair) for different indications (root aneurysm or isolated
AR).
Stefano Mastrobuoni, Laurent De Kerchove and Gebrine El Khoury
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Outcomes of Valve-Sparing Root Replacement with the
Reimplantation Technique
Experience with the David operation is well entered into its third decade, therefore long-
term results of this procedure are available from dr. David himself and other groups.
Traditionally, the first concern relative to this procedure regarded the durability of the valve
function after reimplantation into a vascular graft. David and colleagues reported a
cumulative risk of developing moderate and severe AR of 10% at 20 years . These authors
found that preoperative moderate or severe AR, BAV and aortic dissection were associated
with increased risk of postoperative AI in univariable analysis. In our experience we observed
a significant impact of time since surgery on valve function and a risk of grade 3+ and 4+ AR
of 6% at 10 years10. We also found that severe preoperative AR and residual AR at the end
of the procedure are associated to a higher progression of postoperative AR . Nonetheless
freedom from AV reoperation was 95% at 15 years in Toronto14 and 90% at 10 years in our
experience10. Further, a meta-analysis of 31 studies on VSRR comprising more than four
thousand patients estimated in 0.23% patient-year the linearized rate of major bleeding
events, 0.41% patient-year the rate of thromboembolism and 0.23% patient-year the
occurrence of infective endocarditis . Finally, 10-year survival is in the range of 80-90% in dr.
David’s and in our series and higher than survival after valve replacement. Recently Klotz et
al. showed that long-term survival was comparable to that of the matched general population
in Germany. Predictors of late survival were, as expected, age and type A aortic dissection at
time of surgery.
Surely, patient selection is a key point to get improved results. Compared to David’s
experience, in our series we had a higher prevalence of BAV patients and a higher percentage
of cusp and patch repair. We believe indeed that many valves can be spared even if they
require cusp repair and that a slightly higher risk of reoperation is the trade-off to avoid a
prosthesis. It is nonetheless a matter of experience to rule out regurgitant aortic valves that are
too diseased for a repair with an acceptable outcome. The key factors that predict repair
success or late failure are: the quality and quantity of cusp tissue to begin with, mobility of
the cusps, coaptation and residual AR at the end of repair. Limited calcifications or fibrosis
do not contraindicate this procedure but extensive fibrosis that limit cusp mobility or that
require resection and patch repair are associated to suboptimal results. Moreover, low
coaptation into the root, low effective height and a short length of coaptation are risk factors
for late failure, despite satisfactory cusp mobility.
Outcomes of Isolated Aortic Valve Repair
Sharma and coll. from the Mayo clinic reported their long-term results of AV repair for
isolated cusp disease. They observed a freedom from at least moderate AR of 58% and a
freedom from reoperation of 72% at 15 years following surgery. Significant predictors of late
reoperation were severe AR before surgery and more than mild AR at discharge after the
intervention. It is noteworthy that over 80% of patients in this series had an annuloplasty by
means of the Cabrol sub-commissural stitches (SCA). A large analysis from the Cleveland
Clinic, pooling a certain number of different techniques for AV repair, found a freedom from
reoperation of 90% at 10 years after surgery and that annular support was associated with best
Aortic Valve Repair
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valve durability. We have demonstrated improved results of AV repair with complete
circumferential annuloplasty by means of valve sparing – reimplantation compared to the subcommissural annuloplasty if the VAJ is dilated (>28mm) regardless of the root diameter10 .
Schäfers and coll. and Lansac and coll. have also shown that results of isolated valve repair,
particularly in BAV, are improved if the repair is associated to annuloplasty, whether by
suture annuloplasty or external ring . With suture annuloplasty dr. Schäfers observed a
freedom from reoperation of 92.6% and freedom from significant AR (>2) of 79.5%. With the
external ring, dr. Lansac reported a freedom from reoperation and freedom from AR>3 of
97.5% and 82.2% respectively at 7-year follow-up. Padial and coll. already in the ‘90s
demonstrated that patients with severe AR have a significantly larger aortic annulus than
patients with moderate or mild AR. Therefore, it is well agreed that the annuloplasty is a
necessary adjunctive technique also in isolated AV repair, particularly if the VAJ is bigger
than 26-28mm.
In our current approach, we favor valve sparing-reimplantation when the VAJ is dilated
(>28mm), in BAV whenever we aim to imrpove valve symmetry or when, despite the normal
diameter, the aortic root presents a thin and diseased wall. Whenever the VAJ is dilated over
26mm but there is no root dilatation nor wall disease, and the valve is tricuspid, we prefer to
employ an external annuloplasty with a suture band.
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aortic root aneurysm: a systematic review and meta-analysis. Ann Thorac Surg 2015
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In: Perspectives in Aortic Valve Disease ISBN: 978-1-53618-769-4
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Editor: Giovanni Concistrè © 2020 Nova Science Publishers, Inc.
Chapter 20
AORTIC VALVE SPARING:
REMODELING AND REIMPLANTATION
Ruggero De Paulis
Cardiac Surgery Department, European Hospital, Rome, Italy
“Aortic valve sparing” (AVS) surgery, introduced in the 90s by Yacoub with the
remodeling and by David with reimplantation technique, has gained increasing attention
and more evident scientific relevance in the last decades. In recent years the number of
AVS interventions has significantly increased through a better knowledge of anatomy
and pathophysiology of the aortic root. The sharing and appreciation of positive clinical
results along with progressive modifications of the original techniques, has helped in the
worldwide spread of this surgery.
The concept that the aortic valve regurgitation can occur in patients with normal
aortic cusps is not new but, paradoxically, for many years, we have been replacing intact
aortic valves while somehow preserving enlarged aortic roots. Today, the leaflets
integrity in the context of aortic root pathology is evaluated only after the root has been
excised and normal root anatomy has been re-established. The complex interaction
between the aortic valve leaflets and the skeleton of the aortic root - annulus and sinotubular (ST) junction - is the basis for a normally functioning aortic valve. Annular
and/or ST junction dilatation are the key elements in determining aortic valve
regurgitation; consequent stress on the leaflets leads to intrinsic cusp defects. It is
therefore important to understand how re-establishing the normal relationship of all aortic
root components is the foundation for a good AVS procedure. Based on these premises
echocardiography and diagnostic radiology (computed tomography and magnetic
resonance imaging) are fundamental for both the selection of the AVS surgery candidates
and for the clinical follow-up and the research studies.
Today is possible to perform both the remodeling and the reimplantation procedure
while achieving an anatomical root reconstruction with excellent long-term results.
Especially in young patients, AVS operations have become an established alternative to
Bentall procedure with the important advantage of avoiding the use of valve prostheses
, Raffaele Scaffa and Ilaria Chirichilli
ABSTRACT
Corresponding Author’s Email: rdepaulis58@gmail.com.
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and their inherent incidence of complications in terms of structural valve deterioration,
thromboembolism, endocarditis and hemorrhage.
Keywords: aortic root, aortic valve, aortic operation, aortic regurgitation, aortic aneurysm
INTRODUCTION
“Nothing in nature is without reason; if you understand the reason you don’t need
experience” (“Nessuno effetto in natura è sanza ragione; intendi la ragione e non ti bisogna
sperienza”), said Leonardo da Vinci, who, besides his many attributes as an artist, architect,
anatomist, and military engineer, was also a leading hydrodynamic expert of his time.
Although the whole thrust of Leonardo’s argument is towards experimentation
(“experience”), he gave great importance to acutely observing the different forms of each
anatomical portion to understand its function. Undoubtedly, Leonardo understood almost
everything necessary to know how to properly approach and surgically treat both aortic valve
and aortic root pathology. The surgeon’s ideal to pursue the most physiologic result by the
discipline of surgery in which he excels truly stands in line with the medieval genius attempts
to find nature’s truths through his art [1].
Aortic valve sparing (AVS) procedures - remodeling and reimplantation, respectively
introduced by Yacoub and David - were first described nearly 40 years ago [2, 3]. However,
they have gained popularity only in the last two decades because of an in-depth knowledge of
the “functional anatomy” of the aortic root and a collective evidence of satisfactory long-term
results. Basically, after excision of the Valsalva’s sinuses of the native aortic root (Figure 1),
the scalloped aortic valve is sutured to a triple-tongue-shaped Dacron graft (remodeling) or
entirely incorporated into a straight Dacron graft (reimplantation). The “remodeling” has
always been considered physiologically superior to the “reimplantation” procedure for its
ability to obtain a lifelike reconstruction of the Valsalva’s sinuses. On the other hand, the
“reimplantation” has always been considered more radical for its stabilization and support of
the aortic annulus to prevent further annular dilatation.
Figure 1. Aortic root preparation for a valve sparing procedure procedure in TAV
(TAV: Tricuspid Aortic Valve).
Aortic Valve Sparing
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During the 90’s, there was an endless “philosophical” discussion about the peculiarity of
the two different types of surgery but without a significant diffusion in the clinical usage of
any of the two procedures. From 2000 on, it has been a progressive and worldwide diffusion
of the AVS procedures with several modifications to overcome the apparent limitations of
both original approaches. In fact, until 2000, AVS-focused publications did not exceed 20
articles; in the following years, almost 300 publications have progressively appeared. The
most significant world literature of the past 2 years has been selected and commented by us in
a recent review [4].
Despite all these years of surgical experience acquired amongst “aortic surgical teams”
confusion still exists on the weaknesses and strengths of both remodeling and reimplantation
procedures. It seems obvious that preoperative anatomical conditions combined with the
many “customizations” of the techniques may differ significantly in the surgical scenario
making it complicated an objective comparison between the two procedures.
However, in the last years, the differences between these two procedures have narrowed
and nowadays both can guarantee an optimal anatomical and physiological root
reconstruction with increased long-term valve durability. In the 21st century, avoidance of a
valve replacement is slowly becoming mandatory in the young patient population, in which
anticoagulation therapy and its related morbidity are undesirable.
THE RATIONAL
A strategy is a generalized approach to problems; a technique is something you say or do
in a particular way. In team games (especially in basketball and soccer) an “assist” is the end
of an action with which a player puts his teammate in a position to score (the pass that
precedes a shot or goal). As a consequence of such philosophy, once the appropriate surgical
strategy has been chosen (“the action and the assist”), the “goal” could be a simple and
reproducible construction technique (“more science than art”).
A correct approach to “spare” an aortic valve includes: 1) a wide knowledge of anatomy
and physiology of the aortic root, 2) a systematic imaging assessment (echocardiography and
computed tomography), 3) a knowledge of the two major procedures along with an
intraoperative evaluation of aortic valve configuration. These skills facilitate patient selection
and patient-tailored surgical planning.
Surgical Anatomy and Physiology of the Aortic Root
To identify an appropriate surgical strategy and technique, a deep understanding of the
aortic anatomy and physiology is strongly recommended. Just like the mitral valve, also the
human aortic valve and the root have been identified as a 3-dimensional complex of different
elements, constituting a functionally dynamic structure. Although this aortic region has been
anatomically well described, there is still controversy on the best nomenclature of its distinct
elements, particularly the aortic annulus, which has several definitions.
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Figure 2. Dissection of the aortic root in preparation for aortic valve reimplantation. At the level of the
Non-Coronary sinus the dissection reaches the level of the VBR despite the presence of muscular fibers
as part of VAJ (VBR: Virtual Basal Ring; VAJ: Ventriculo-Aortic Junction).
The aorto-ventricular junction (AVJ) represents a real anatomical region with a specific
histologic entity where ventricular structures (including the muscular septum, mitro-aortic
curtain, and membranous septum) join the arterial system. Diagrammatically, the AVJ is
characterized by a relatively circular line created by joining the base of inter-leaflet triangles
with the lower third of Valsalva’s sinuses, slightly above the nadir of the aortic leaflets
crossing in several points the semilunar line of attachment of the aortic leaflets (this landmark
is evident only at the level of the muscular portion of the aortic root). Histologically, the AVJ
has a variable thickness along the circumference of the aortic root (range 1 to 4.6 mm;
maximum at the level of the right coronary sinus). Differently, the virtual basal ring (VBR) it
is no more than a virtual circular line positioned inside the left ventricle outflow tract, simply
created by connecting the nadirs of each leaflet, without a real anatomic counterpart and it is
the echocardiographic parameter considered to provide a measurement of the diameter of the
aortic annulus. Noteworthy, the relationship between VAJ and VBR helps in a better
understanding: the two anatomical landmarks, VAJ and VBR are further away at the level of
the right coronary sinus and closer at the level of the non-coronary sinus. In the basal part of
the non-coronary aortic sinus, the VAJ is entirely constituted by arterial wall, comprised in a
portion of the mitro-aortic curtain, and precisely at this level VBR and VAJ coincide [5]
(Figure 2).
The basal attachments of the aortic leaflets describe three semilunar lines with a
distinctive crown-like formation and represent the hemodynamic boundary line between the
left ventricle and the arterial system. The distal limit of the aortic root is marked by a
supravalvular crest, called the sino-tubular (ST) junction. Inside the aortic lumen, the ST
junction appears as a marginally elevated ridge of thickened aortic wall, while on the outside
is usually less identifiable. The ST junction, with its specific relationship with the other
components of the aortic root, plays a fundamental role in the function of the aortic valve.
The aortic root as a whole naturally follows the curvature of the ascending aorta and it has
been noted that there is the presence of a tilt angle of 5.5°–11° between the lines passing
through the VBR and ST junction planes [6, 7]. In few simple words, the aortic annulus (VAJ
or VBR), along with the ST junction and the three commissural posts connecting these two
rings, represent the skeleton of the root (see below) that regulates the proper geometry of the
aortic valve and root complex. The sinuses of Valsalva are defined as three-dimensional
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