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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 16
REDO SURGERY FOR AORTIC VALVE:
DEMOGRAPHICS AND OPERATIVE OPTIONS
1,
Antonio Miceli
1
Minimally Invasive Cardiac Surgery Department,
Gruppo Ospedaliero San Donato, Milan, Italy
Redo aortic valve surgery (RVAD) is a challenging procedure and associated with
higher intraoperative and postoperative risks compared to first operation. It is technically
more demanding than primary operation, because of adhesions and scars around the
heart, the risk of iatrogenic injury to cardiovascular structures and the presence of cardiac
and non-cardiac morbidities related to aging. These surgical difficulties determine
prolonged operative times, which increase the risk of bleeding, transfusion-related
morbidity and organ failures [1, 2]. According to EuroSCORE II, patients undergoing
redo surgery have 2-fold increased risk of death compared to those undergoing isolated
surgery [3].
Historically, mortality rate is high and ranges from 5% to 17% [4-7]. Nevertheless,
advancements in cardiac surgery, myocardial protection and alternative surgical strategies
have dramatically reduced operative complications, making redo surgery for aortic valve
almost safe as primary cardiac surgery, reaching an overall mortality of 4 - 6% [8-10]. An
analysis of STS database has shown that compared to primary AVR, RAVR was
associated with higher operative mortality (4.6% vs. 2.2%), post-operative stroke (1.9 vs
1.4%), pacemaker requirement (11% vs. 4.3%) and vascular complications (0.06% vs.
0.01%) [11].
Keywords: aortic valve disease, reintervention, conventional aortic surgery, minimally
invasive surgery
, MD, PhD and Mattia Glauber1, MD
Istituto Clinico Sant'Ambrogio,
ABSTRACT
Corresponding Author’s Email: antoniomiceli79@alice.it.
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INTRODUCTION
The number of patients undergoing repeat surgery is increasing because of aging,
improved durability of newer generation tissue valves, and patient’s preference for biological
valve to avoid long-life anticoagulation. According to Society of Thoracic Surgeons (STS)
national database report, the use of bioprostheses increased from 42% in 1996 to 78.4% in
2006 [12].
In addition, the introduction of valve in valve transcatheter aortic valve implantation, as
alternative strategy for the treatment of failed bioprostheses, will further increase this
percentage. It has been estimated that after AVR, 10% of patients receiving biological valve
will require a reoperation within 10 years. After 15 years, this percentage rises up to 30%. As
consequence, reoperation for bioprosthetic valve degeneration represents the most common
indication for repeated aortic valve replacement [13]. Nevertheless, The incidence of
reoperation for mechanical valve is low and amounts < 0.3% per patient-year [14].
Paravalvular leaks, pannus formation and acute thrombosis are the most frequent causes of
mechanical valve replacement.
Other indications are prosthetic valve endocarditis, failed valve repair, paravalvular leak.
An observational, nationwide, population-based cohort study on 26, 580 patients undergoing
aortic valve replacement reports that the overall incidence of prosthetic valve endocarditis
(PVE) after AVR is 0.57% per person-year. The risk of PVE is highest during the first year
after AVR with 1% per person year; then, the yearly rate of PVE is halved and remains stable
during years [15].
Despite not frequent, paravalvular leak (PVL) is the most common nonstructural valve
after valve replacement. The annual incidence annual incidence of paravalvular leak ranges
between 0.1% and 1.0% per year after aortic valve replacement, whereas the cumulative
incidence of PVL recurrence after AVR is was 3%, 14%, and 32%% at 1, 5, and 10 years,
respectively. Interestingly, the number of previous surgeries is a predictor PVL
recurrence [16].
Last indication for redo AVR is failure of aortic valve repair. Aortic valve repair is a
procedure that should not be done in low volume institution on an episodic basis. In this
regard, it is difficult to estimate the incidence.
In experienced center, freedom from reoperation can reach 96% after almost 20 years,
whereas for bicuspid aortic valve repair freedom from reoperation after 10 years is 90%
[17, 18].
In addition to traditional risk factors of EurosCORE II, preoperative intraaortic ballon
pump, number of redo operations and previous CABG surgery have been associated with
higher risk of in-hospital mortality.
A preoperative score card was created for the preoperative estimation of in-hospital
mortality in redo cardiac procedures [19]. Table 1 shows preoperative variables associated
with a score point.
The sum of the score for each individual risk factor gives a total score, which assigns a
percentage of risk. Six risk categories of in-hospital mortality were identified: 1. Score 0 - 6
mortality risk 0 - 5%; score 6.5 - 10.5 mortality risk 5 - 10%; score 10.5 - 12 mortality risk 10
- 15%; score 12.5 - 14 mortality risk 15 - 20%; score 14.5 - 19 mortality risk 20-40%; > 19
mortality risk >40%) [19].
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Risk factor
Score
Age (years):
<60
60-69
70-79
≥80
0
2
5
6
Current procedure:
Isolated aortic valve or isolated mitral valve
Isolated CABG
Not isolated CABG, isolated aortic valve, or isolated mitral valve
0
1
5
Previous CABG
2
Number of previous sternotomies
1
2
3
0
1
5
Peripheral vascular disease
2
Renal failure (creatinine>176 μmol/L)
2.5
One or more of the following:
Urgent/emergent procedure within 24 h
MI within 21 days,
Active endocarditis
IABP placement
6
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Table 1. Score for preoperative prediction of in hospital mortality risk [19]
CABG = coronary artery bypass grafting; IABP = intraaortic balloon pump; MI = myocardial
infarction. According to ref Launcelott et al. [19].
SURGICAL APPROACH
Resternotomy
Median resternotomy is the most common and standard approach for the treatment of
redo aortic valve surgery, as it gives full access to whole of the heart. However, in reoperative
patients, repeating sternotomy may increase surgical risk because of the risk of iatrogenic
injury of the right ventricular, ascending aorta, innominate vein and grafts. The incidence of
hemorrage after resternotomy is between 2% and 6% per patient reoperation [20].
Preoperative computed tomography scanning is mandatory to evaluate the relationship among
these structures and sternum and identify patients at risk of injury during reentry. If
pericardium was closed to previous during the primary procedure, median sternotomy is quite
safe, although we recommend having cardiopulmonary machine ready to start in case of
catastrophic events. Conversely, if the mediastinal contents are closely attached to the
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sternum, an alternative strategy is to perform resternotomy once the heart is empty through
cardiopulmonary bypass (CPB) machine, cannulating the femoral vessels. In presence of
advanced peripheral vessel disease, axillary cannulation may be useful to reduce the risk of
stroke and vessels injuries. When major hemorrhage occurs on sternal reentry for right
ventricular or aortic injury, sternotomy should be abandoned and chest reapproximated. CPB
should be established cooling down the patient for potential circulatory arrest and the
remaining sternal division can be completed and injury repaired. After safe re-entry, the
patient may be weaned off for further dissection to avoid prolonged cardiopulmonary bypass
time. Careful attention should be taken to avoid de-adventializing the aorta, as well as the
space between pulmonary artery and aorta, innominate vein and right phrenic nerve during
dissection at the level of superior vena cava.
Minimally Invasive Approach
The number of minimally invasive procedures for isolated primary AVR is increasingly
performed, as minimally invasive AVR (MIAVR) has shown excellent results in terms of
mortality, morbidities and patient’s satisfaction. It reduces risk of bleeding, blood transfusion
and associated with shorter hospital stay [21]. In the setting of redo surgery, the rational of a
minimally invasive approach is to minimize surgical trauma because it does not require
extensive dissection, reduce the risk of cardiac structures injuries and consequently less
bleeding. However, several concerns have been expressed regarding myocardial protection,
prolonged operative times, chambers dearing, as well as retrograde perfusion related to
peripheral cannulation. A systematic review and meta-analysis on 441 redo patients
concluded that minimally invasive redo AVR is a valid alternative option for patients
requiring redo AVR, as it has showed similar efficacy, mortality and morbidity outcomes
(renal failure, stroke, pacemaker implantation and myocardial infarction) compared
conventional redo AVR [22]. Ministernotomy is the most common minimally invasive
approach used for redo AVR and consists in a J partial resternotomy at the 3rd or 4th
intercostal space. Mediastinal dissection is limited to the only ascending aorta necessary for
aortotomy and aortic clamping. Ministernotomy is our preferred approach for those patients
requiring repeated AVR, especially for degenerated biological valve or mechanical valve
dysfunction. Nevertheless, the introduction of sutureless valves and our increased experience
in right anterior minithoracotomy for primary AVR have facilitated the redo AVR via right
minithoracotomy.
In this setting, the computed tomography allows to evaluate the anatomic relationship
among the intercostal spaces, ascending aorta, and aortic valve. Patients are suitable for RT
only if the following criteria were met: (1) at the level of main pulmonary artery, the
ascending aorta is rightward (more than one half located on the right in respect to the right
sternal border) (2) the distance from the ascending aorta to the sternum is between 2cm-10cm
and (3) good valve exposure with α angle (angle between the midline and the inclination of
ascending aorta) ≥ 45° (Figure 1). We describe our surgical approach. Minimally invasive RT
AVR is performed through a 5 to 7cm skin incision placed at the level of the second
intercostal space without rib resection.
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Figure 1. Evaluation of anatomic relationship among the intercostal spaces, ascending aorta, and aortic
valve with CT-scan.
Figure 2. Transverse aortotomy.
The right internal thoracic artery is excluded and vacuum-assisted cardiopulmonary
bypass (between -30mm Hg -40mm Hg) is established though femoral vessels. Mediastinal
dissection is limited to the ascending aorta for aortic clamping. After clamping, antegrade
crystalloid cardioplegic solution is given into the aortic root or selectively into the coronary
ostia in presence of severe regurgitation for cusp fractures. This approach is used also in
patients with patent LIMA-LAD graft without the need of cooling the patients. In case of
significant blood flow out the coronary ostium and obscured surgical field, the pump flow is
turned down temporarily and a pediatric vent is used through the aortic annulus for better
visualization.
A transverse aortotomy is usually performed 2 - 3cm above the sinotubular junction
(Figure 2).
Once the prosthesis is removed, the aortic annulus is inspected and the excess of pannus
or fibrotic tissue is removed to favor annular, taking care to avoid annular defects. After
sizing, 3 guiding 4 - 0 Prolene sutures are placed at the nadir point of each valve sinuses for
accurate alignment of the inflow portion of the prosthesis into the aortic annulus. Often, nadir
points are not evident, as the previous prosthesis has altered annulus geometry. To manage
this problem, we recreate 3 nadirs that are positioned at approximately 120 degrees.
Landmarks are right and left coronary artery and previous commissures. To achieve this
result, the surgeon may use instruments such as a sizer with 120-degree markings to recreate a
normal nadir. Then the valve is collapsed using a specific device system and connected to the
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guiding sutures through 3 bottom holes placed on the midpart of the inflow ring. The valve is
released into the aortic annulus and once coaptation of the 3 leaflets has been checked, a
balloon was inserted into the sutureless valve and expanded with warm saline solution for 30
seconds at a pressure of 4 mmBar. Finally, the 3 guiding sutures were removed; the valve is
again checked for the correct position, and the aortotomy is closed using 4-0 or 5-0 running
sutures.
Valve in Valve for Failed Aortic Bioprosthesis
The operative surgical risk and the non-inferiority of transcatheter AVR (TAVR)
compared with conventional AVR in high and intermediate risk patients, have brought
medical community to consider the concept of valve in valve TAVR for failed aortic
bioprostheses [23-26]. In August 2015, the Food and Drug Administration approved the use
of percutaneous valves for patients in need of a second tissue AVR after undergoing previous
one. Several studies show that valve in valve TAVR is a safe and clinically effective
procedure with similar mortality compared to surgical AVR at least in the short term [27-29].
Nevertheless, valve in valve TAVR requires and extensive preoperative work up and is
associated with complications such as coronary obstruction (stentless internally oriented
stented bioprosthetic valves) and high gradients with small failed aortic bioprosthes [30].
Moreover, no long-term results are available.
CONCLUSION
Redo surgery for aortic valve is expected to increase in next years because of aging and
patients’ preference for biological valve to improve quality of life. Despite the surgical risk is
higher than first operation, advancement in cardiac surgery in terms of minimally invasive
approaches, myocardial protection and sutureless technology, have improved postoperative
outcomes. Valve in Valve TAVR is a safe and effective procedure in high-risk patients;
however, the lack of long term durability and the high gradients in small prostheses make this
procedure still not indicated in young and low risk patients.
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[20] Dobell, A. R. C., Jain, A. K. Catastrophic Hemorrhage during Redo Sternotomy. Ann.
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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 17
AORTIC PROSTHESIS: MECHANICAL
AND SUTURED BIOLOGICAL VALVES
1,2,3,
Giuseppe Santarpino
and Pasquale Mastroroberto3
1
Anthea Hospital, GVM Care and Research, Bari, Italy
2
3
Cardiac Surgery Unit, Department of Experimental and Clinical Medicine,
Paracelsus Medical University, Nuremberg, Germany
University “Magna Graecia” of Catanzaro, Catanzaro, Italy
Within a context of innovation, between transcatheter prostheses, stentless and
sutureless prostheses, the use of stented and mechanical prostheses seems to represent a
“historical” chapter of cardiac surgery. This chapter provides an overview of the most
commonly used prostheses in terms of prevalence, and therefore of importance, also from
an economic perspective. Furthermore, new studies on biological designs and materials,
as well as new anticoagulant therapy protocols, open new frontiers for the future use of
these prostheses (still) in a large proportion of patients suffering from aortic valve
disease.
Keywords: mechanical valves, sutured biological valves
INTRODUCTION
The progressive rise in the average age of the population has resulted in a growing
proportion of elderly patients who may benefit from medical and surgical treatment options
that were previously offered only to younger subjects. This applies, for example, to aortic
valve replacement for symptomatic severe aortic stenosis, where biological tissue valves are
, Giuseppe Filiberto Serraino3
ABSTRACT
Corresponding Author’s Email: gsantarpino@gvmnet.it.
Giuseppe Santarpino, Giuseppe Filiberto Serraino and Pasquale Mastroroberto
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generally considered the device of choice for older patients. Aortic valve bioprostheses are
commonly implanted in the current era (also in younger patients) as they may obviate the
need for anticoagulation while providing better hemodynamic performance and a more
favorable quality of life. The steady increase in the use of biological valves has prompted the
development of several different models of conventional stented bioprostheses.
In this chapter we describe the features of different bioprosthetic valve models. As these
devices are well recognized and available on the market worldwide, the ultimate aim is to
understand how to select the most appropriate prosthetic model for the individual patient in
order to establish the indication for aortic valve replacement with a stented bioprosthesis
based on a patient- rather than a prosthesis-oriented approach.
Furthermore, we will describe the new anticoagulation regimes necessary for mechanical
prostheses and their hemodynamic characteristics; both factors that can recover space for
these prostheses, even in non-young patients.
Finally, we will describe new biological tissues and models that seem to have excellent
future prospects based on in vitro studies that may represent a hope of reduced risk of
structural valve degeneration (SVD) even in young patients who want to make a “biological”
choice.
BIOLOGICAL MODELS
The classic classification of stented biological valves divides them into two large
families: porcine prostheses and pericardial prostheses. In reality, and in light of the most
recent studies on the hemodynamic effects and on the risk of SVD, it is necessary to divide
the prostheses - probably more important than the aspect of the origin of the biological tissue
- into two other families: those with leaflets mounted inside the stent and those with leaflets
mounted outside.
One of the models with externally mounted leaflets is the Livanova Crown PRT. This
stented bioprosthesis is a device built on the previous generation of the Mitroflow aortic valve
model. The Mitroflow valve design was already shown to provide good hemodynamic
performance, especially in patients with small aortic annulus [1, 2]. The valve design consists
of a single bovine pericardium layer mounted outside the stent, combined with an advanced
tissue treatment - the phospholipid reduction treatment (PRT) - which is intended to bolster
durability through mitigation of valve calcification. The Crown PRT bioprosthetic aortic
valve can be implanted in either the supra-annular or intra-annular position. Since its market
introduction in 1982, the Mitroflow pericardial bioprosthesis demonstrated good long-term
performance in both European 1 and north-American 2 multicenter studies. However, Sénage
et al., reported a high incidence of structural valve deterioration with the Mitroflow
pericardial bioprosthesis [3]. For a deeper understanding of this concept and the difficulty in
comparing different models in different patients, we suggest meta-analysis (2017): Fischlein
T., et al., Patterns of use and durability for the Mitroflow aortic valve: a systematic review of
the literature. J Cardiovasc Surg (Torino) [4-6].
The second model with leaflets mounted outside the stent is the St. Jude Trifecta. The
Trifecta valve is a third-generation heart valve that complements the St. Jude Medical Epic
and Epic Supra bioprosthetic aortic valves. It is a one-leaflet stented pericardial valve
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