Aortic Valve Replacement - Sostituzione Valvola Aortica

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Luigi Farina Facoltà di Medicina e Chirurgia Università “Sapienza” - Polo Pontino Anno Accademico 2013-2014 Esame di Inglese III Prof. L. Herdon Aortic Valve Replacement

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Transcript of Aortic Valve Replacement - Sostituzione Valvola Aortica

  • Luigi Farina

    Facolt di Medicina e Chirurgia

    Universit Sapienza - Polo Pontino

    Anno Accademico 2013-2014 Esame di Inglese III Prof. L. Herdon

    Aortic Valve Replacement

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  • 2

    SUMMARY

    Historical Background .............................................................................. 4

    Heart Anatomy and Physiology ................................................................ 7

    Aortic Valve Anatomy ............................................................................ 11

    Steps of AVR - Open Heart Surgey ........................................................ 12

    TAVR - TRANSCATHETER AORTIC VALVE REPLACEMENT .... 14

    Preoperative management ................................................. 14

    Patient selection ................................................................. 14

    Preparation ........................................................................ 14

    Operative techniques ......................................................... 14

    Imaging .............................................................................. 14

    Surgical access .................................................................. 16

    Balloon valvuloplasty ........................................................ 18

    Positioning ......................................................................... 19

    Deployment ........................................................................ 19

    Surgical closure ................................................................. 20

    Conclusion ......................................................................... 20

    FAQ......................................................................................................... 22

    What causes a failure of the aortic valve? ......................... 22

    There are signs of a failure of the alarm aortic valve? ..... 22

    How do i know if i have to be at work aortic valve? ......... 23

    There are differences between implants and mechanical

    organic? ............................................................................. 23

    How is the surgery performed? ......................................... 24

    Why i need surgery? .......................................................... 24

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    Alternatives to surgery ....................................................... 25

    Results of treatment failure ................................................ 25

    What 'the risk of surgery? .................................................. 25

    What will my condition after replacing aortic valve? ....... 26

    Article 1 Surgical treatment of aortic valve endocarditis .................... 27

    Article 2 Aortic stiffness is an indicator of cognitive dysfunction ...... 28

    Article 3 Fast-implantable aortic valve ............................................ 29

    Article 4 - Retrograde cardioplegia administration ................................ 30

    Article 5 mid-term results for aortic roof replacement ........................ 31

    Article 6 Percutaneous aortic valve replacement ................................. 32

    Bibliography ........................................................................................... 33

    Sitography ............................................................................................... 33

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    HISTORICAL BACKGROUND

    In folio 115 of the Corpus of the anatomical Studies Leonardo Da Vinci

    shows numerous drawings of the aortic valve and the structures attached to

    it. This folio is one of the richest examples of precise and accurate method

    of Da Vinci, but also the most difficult to clarify the anatomical pages of

    Leonardo. The constant Leonardo's interest in the aortic valve is shown by

    the frequent recurrence of drawings of the structure of the tricuspid aortic

    valve, pointing to the fact that he was particularly attracted by its symmetry.

    In addition, he wrote: "Non permettere a nessuno che non sia matematico

    di legere mja principles" ("Do not let anyone who is not a mathematician

    read my principles"). Already in the school of Pythagoras, the circle in the

    plane and the sphere in space, were considered the perfect figures for their

    symmetry and rotation. In fact, in the drawings of Leonardo, the tricuspid

    aortic valve, in a circle appeared to be a perfect example of symmetry and

    rotation.

    The interest in Leonardo, as a mathematician, not only ended with the

    geometric symmetry of the aortic valve, but it also expanded to fluid

    dynamics. When each component was analyzed, Leonardo guessed its

    function with a vivid imagination and tried to reconstruct the whole.

    Analyzing the flow through the vessel and breasts had been able to

    understand how the task of the aortic valve was done, in particular for what

    concerns the opening and closing.

    The concept of morphological and functional unit of the aortic valve is

    introduced already Leonardo with a simple question: Perch il buso

    della arteria aorto triangolare?..." (" ... Why is the aortic artery orifice

    triangular? ... ").

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    It was probably Erasistratus, in the third century BC, who first described

    the three membranes at the level of the aortic and pulmonary orifices. The

    graphical representation of a tricuspid aortic valve (but also lung) is one of

    the first in the history of medicine, although Leonardo did not exclude the

    possibility that the valves had 4 or 2 flaps.

    And 'certainly hard to believe that Leonardo had ever seen a Quadricuspid

    or bicuspid aortic valve, while it is more likely that it was a result of his

    fertile imagination. The fact is that the incidence of bicuspid aortic valve is

    about 0.52% in each of the 100 infants and 0.008% in the case of valve

    Quadricuspid. Surely, Leonardo had little chance to find a bicuspid valve

    and a valve Quadricuspid even less likely in his 30 anatomical dissections,

    if we consider that Simmonds reports only 2 cases of valve Quadricuspid in

    a total of 25666 autopsies. Leonardo clear and clearly differentiated three

    different anatomical configurations, which seem rather a geometric

    reasoning that a reproduction of a direct experience. Determined that: "...

    per la qual cosa langolo pi ottuso pi forte chellangolo retto del

    quadra..." ("... for this reason, the obtuse angle is stronger than the right

    angle of the square ..."). Indeed, in a tricuspid valve closed, in the center of

    the aorta each flap forms an angle of 120 while in the configuration with

    four flaps is 90. He explained that the orifice of the valve with four square

    edges, is larger than the triangular orifice inserted in the same circle;

    accordingly, the valve

    leaflets Quadricuspid are

    weaker, because the

    corners of the closure are

    more remote from the

    base of the triangle. In

    this way, Leonardo in a

    simple way, anticipated

    the concept of increased

    stress of the flaps in the presence of congenital diseases. This concept was

    recognized much importance in the design and construction of biological

    prostheses or in cases of conservative surgery of the aortic valve.

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    Leonardo clearly understood that the durability of the valve was largely

    dependent on

    the fact that the

    aortic valve

    leaflets were

    shares of the

    aortic wall.

    Observation of

    his drawings

    you understand that Da Vinci had also realized that the valve leaflets were

    not connected in a circular manner but rather in the manner of the crown

    (the fibrous skeleton) defining small triangular structures of the ventricle,

    which have been recently re-evaluated.

    Leonardo wrote that the aortic valve opens from the blood that "affect" and

    close the blood that is "reflected". Also considered that the "impetus" of the

    blood goes from the ventricle to the aorta and that this stretches and expands

    the flaps upward. He also explained that the speed of the blood could depend

    on the different diameters of the aorta: ...major velocita nella mjnor

    larghezze dessa canna

    ("...the higher the speed

    when the port is smaller,

    less when it is larger ...").

    For Da Vinci, the area of

    coaptation was of vital

    importance in

    maintaining the cusps

    closed, so that the blood

    would not return back into the ventricle. I realized that was not the case in

    the coaptation level of the free margin but at the level of the "belly" of the

    flaps.

    Thanks to the intuition and reasoning of Leonardo, the importance of the

    area of coaptation in the efficiency and durability of the valve function are

    underlined.

    In conclusion, not only Leonardo understood the role of the flow of blood

    through the sinuses of Valsalva, which represents the basis of the complex

    mechanism of closure of the aortic valve, but also the lees a reference to the

    importance of the stress at the level of the aortic valve leaflets, the

    coaptation of the cusps and the concept of functional anatomy at the

    microscopic level.

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    HEART ANATOMY AND PHYSIOLOGY

    The heart is an unequal organ, cable, consisting of involuntary striated

    muscle tissue. Its main function is to set in motion the blood in the vessels;

    for this is comparable to a pump, which, contracting, pushes the blood

    towards the various tissues and organs. Has a shape that resembles an

    upside-down pyramid. At birth, the heart weighs 20-21 grams and, in

    adulthood, reaches 250 grams in women, and 300 grams in humans. The

    heart lies in the chest, at the level of the anterior mediastinum, rests on the

    diaphragm and is slightly shifted to the left. It is surrounded by the

    pericardium, a sac serousfibrous, which has the task of protecting and

    limiting distensibility. The heart wall is formed by three tunics

    superimposed, from outside to inside are named:

    Epicardium: It is the outermost layer, in

    direct contact with the serous pericardium. It

    consists of a surface layer of mesothelial cells that

    rests on the underlying layer of dense connective

    tissue, rich in elastic fibers.

    Myocardium: It is the intermediate layer,

    consisting of muscle fibers. The myocardial cells are

    called cardiomyocytes. It depends both on the

    contraction of the heart, both the thickness of the

    heart wall. It is necessary that the myocardium is

    properly perfused and innervated, respectively by a

    vascular network and a nerve.

    Endocardium: It is the lining of the heart chambers

    (atria and ventricles), consisting of endothelial cells

    and elastic fibers. A separate it from the

    myocardium, there is a thin layer of loose

    connective tissue

    The internal shape of the heart can be divided into two halves: a left and a

    right part. Each part consists of two cavities, or chambers, distinct, called

    the atria and ventricles, within which the blood flows. Atrium and ventricle

    of each half are placed, respectively, one above the other. On the right side,

    you have the right atrium and the right ventricle; on the left side, you have

    the left atrium and the left ventricle. A clear separation of the atria and

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    ventricles of the two halves, there are, respectively, an interventricular

    septal and one. Although the blood flow in the right heart is separated from

    the left, the two sides of the heart contract in a coordinated manner: first the

    atria contract, then the ventricles. Atrium and ventricle of a same half are in

    communication between them and the orifice, through which the blood

    flows, is controlled by an atrioventricular valve. The function of the

    atrioventricular valves is to prevent reflux of blood from the ventricle to the

    atrium ensuring unidirectional flow of blood. The mitral valve belongs to

    the left half, and controls the flow of blood from the left atrium to the left

    ventricle. The tricuspid valve resides, however, between atrium and

    ventricle of the right side of the heart. In the ventricular cavities on both the

    right and left, there are two other valves, called semilunar valves. Resides

    in the left ventricle the aortic valve, which regulates blood flow in the

    direction of the left ventricle-aorta; takes place in the right ventricle to the

    pulmonary valve, which controls the flow of blood in the direction right

    ventricular-pulmonary artery. As the atrioventricular valves, these must also

    ensure unidirectional flow of blood. The vessels tributaries, ie those that

    lead blood to the heart, "downloading" in the atria. To the left of the heart,

    blood vessels are tributaries of the pulmonary veins. For the heart of the

    right tributaries are the superior vena cava and the inferior vena cava. The

    effluent vessels, ie, those that drain away the blood from the heart, branch

    off from the ventricles and those are precisely controlled by the valves

    described above. For the heart to the left, the vessel effluent is the aorta. For

    the heart to the right, the effluent is the pulmonary artery.

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    Blood circulation, starring the heart, is as follows. The right atrium, goes

    through the caval veins, blood rich in carbon dioxide and low in oxygen,

    which has just sprayed the organs and tissues of the body. The atrium, the

    blood goes to the right ventricle and the pulmonary artery take. By this

    pathway, the flow of blood reaches the lungs to oxygenate and rid of carbon

    dioxide. Without this, the oxygenated blood returns to the heart, the left

    atrium through the pulmonary veins. Passes from the left atrium to the left

    ventricle, where it is pushed into the aorta, that is, the main artery of the

    human body. Once the aorta, the blood goes to spray all the organs and

    tissues, exchanging oxygen and carbon dioxide. Depleted of oxygen, the

    blood turn into the venous system to return back to the heart, the right

    atrium, to "recharge." And so it repeats a new cycle, equal to the previous.

    The movements made by the blood occur following a relaxation phase

    which follows a phase of contraction of the myocardium, ie the heart

    muscle. The relaxation phase is called diastole; the contraction phase is

    called systole.

    During diastole:

    The heart muscles of the atria and ventricles, both right and left, is

    relaxed.

    The atrioventricular valves are open.

    The semilunar valves of the ventricles are closed

    The blood flowing through the vessels tributaries, at first, in the atrium

    and then the ventricle. The transfer of blood is not the case in its entirety,

    as a share remains in the atrium.

    During systole:

    It takes place or the contraction of the cardiac muscle. They start the atria

    and, subsequently, the ventricles. We speak more accurately, of atrial

    systole and ventricular systole:

    The amount of blood that was left in the atria is pushed into the

    ventricles.

    The atrioventricular valves close, preventing backflow of blood in

    the atria.

    They open the semilunar valves and ventricular muscle is

    contracted.

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    The blood is pushed into their effluent vessels: pulmonary veins

    (right heart), if it is to oxygenate; aorta (left heart), if it is to reach

    the tissues and organs.

    The semilunar valves are closed again after the blood has crossed.

    Diastole and systole alternate during the blood circulation and the behavior

    of cardiac structures, regardless that the blood is in the right half or the left

    half of the heart, are the same. To complete this overview on the heart,

    remain to be mentioned two other issues of great importance. The first

    concerns how and where does the nervous signal of myocardial contraction.

    The second concerns the vascular system that supplies blood to the heart.

    The nerve impulse that produces contraction of the heart comes from the

    heart itself. In fact, the myocardium is a particular muscle tissue, with the

    capacity of autocontrarsi. In other words, the cardiomyocytes are able to

    generate by itself the nerve

    impulse to the contraction. The

    other striated muscles in the

    human body instead need to

    contract, a signal from the

    brain. If you interrupt the nerve

    network that leads to this

    signal, these muscles do not

    move. The heart, however,

    presents, at the junction

    between the superior vena cava and the right atrium, a natural cardiac

    pacemaker, known as the sinoatrial node (SA node). In general, it is called

    pacemaker referring to artificial devices, capable of stimulating the

    contraction of the heart of patients with certain heart diseases. In order to

    properly conduct the nerve impulse, born in the SA node, the ventricles, the

    myocardium has other key points: in succession, the generated signal passes

    through the atrioventricular node (AV node), the bundle of His, and the

    Purkinje fibers.

    The oxygenation of cardiac cells is up to the coronary arteries, right and left.

    They originate from the ascending aorta. One of their failure results in

    ischemic heart disease. Ischemia is a condition, pathology, characterized by

    the absence or insufficient blood supply to a tissue. The blood, once

    exchanged oxygen with the cardiac tissues, take the venous system of the

    cardiac veins and the coronary sinus, thus returning to the right atrium. The

    entire vascular network of the heart resides on the surface of the

    myocardium, in order to avoid their constriction at the time of cardiac

    muscle contraction; situation, the latter, which would alter the blood flow.

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    AORTIC VALVE ANATOMY

    The aortic valve, or aortic semilunar, is located in the orifice that connects

    the left ventricle of the heart and the aorta. It plays a fundamental role:

    regulating the flow of oxygenated blood from the heart to organs and tissues,

    ensuring unidirectional. At the time of ventricular systole, in fact, the aortic

    valve is open and allows the passage of blood into the aorta. A transition

    took place, the valve closes, preventing reflux. The mechanism of opening

    and closing is dependent on the pressure gradient, the pressure difference

    existing between the ventricular compartment and the aorta. in fact:

    The aortic valve is composed of the following anatomical elements:

    The orifice tube is delimited from the ring. The surface extent of the

    orifice, in the adult, a value between 2.5 and 3.5 cm2.; its diameter,

    instead, measure 20 mm.

    It is tricuspid, that has three flaps (or cusps) of the lunate form. The

    cusps are arranged, on the ring valve, in a staggered manner, such as to

    prevent blood reflux, once the valve is closed. The flaps are made up of

    loose connective tissue rich in collagen and elastic fibers. As for the

    other heart valves, tissue vascularization does not have its cusp, and,

    even, a kind of nervous and muscular control.

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    STEPS OF AVR - OPEN HEART SURGEY

    1. Engraving chest, sternum and

    divergence

    2. Opening the pericardium and

    stripped of the heart and blood

    vessels

    3. Cannulation of the ascending aorta.

    The blood begins to circulate in the

    heart-lung machine

    4. Opening the right auricle and

    cannulation for the machine

    5. Preparation cardioplegia

    6. Aortic cross-clamping and cardiac

    arrest

    7. Aortotomia and access to the valve

    8. Introduction ring gauge to choose

    the right size of the valve

    9. Finishing ostium valve prosthesis

    to accommodate

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    10. Positioning stitches detached cardinal points ostium valve

    11. Suture of the sutures on the ring

    where the valve will be implanted

    with the device

    12. Suture of the prosthesis that will

    be positioned ostium prepared

    13. Valve positioning and fastening of

    points of closure

    14. Placing implants in the seat

    15. Cut points and elimination

    cardioplegia

    16. Spontaneous and gradual onset of

    cardiac activity

    17. With Defibrillation you have the

    normal recovery of cardiac

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    TAVR - TRANSCATHETER AORTIC VALVE REPLACEMENT

    Successful TA-TAVR is discussed in eight sequential steps: Patient

    selection, Preparation, Imaging, Surgical access, Balloon valvuloplasty;

    Positioning; Deployment and Surgical closure.

    PREOPERATIVE MANAGEMENT

    PATIENT SELECTION

    Patient selection is the single most important step that can determine success

    or failure of TA-TAVR.

    PREPARATION

    The patient is placed in the supine position and elevation of the left chest is

    not routinely required. All electrical cardiogram leads and defibrillator pads

    are placed appropriately but out of the way of the anticipated fluoroscopy

    sites and allow access to the sternum and left thorax. Lines for continuous

    arterial blood pressure monitoring and oximetry are placed before the

    patient goes under a general anaesthetic and is intubated. TA-TAVR can be

    performed without general anaesthesia, however, very limited experience

    has been reported at the present time.

    Early in the development of the procedure, the left lung was collapsed to

    allow for better visualization of the left ventricular apex. However, it has

    subsequently been found that the left lung rarely interferes with exposure of

    the ventricular apex. Lung isolation is no longer required. Pulmonary

    arterial catheter for continuous cardiac output monitoring is reserved for

    patients with poor ventricular function.

    For precautionary reasons, an important part of the preparation process is

    the presence of perfusionist and a primed cardiopulmonary bypass circuit,

    in the event of hemodynamic instability and surgical misadventures.

    OPERATIVE TECHNIQUES

    IMAGING

    TA-TAVR was performed in the operating room using a portable C-arm

    fluoroscope. However, the image quality was found to be rather poor to the

    point where it was difficult to visualize the aortic valve. A greater quantity

    of dye injection at the aortic root was used to better define the native aortic

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    valve (AV) and this was of some concern as a large dye load can be

    hazardous in patients with compromised renal function. Moreover, poor

    visualization can be a major causative factor for valve malpositioning,

    paravalvular regurgitation and embolization. With this in mind, it is strongly

    advised that TA-TAVI should only be undertaken in a hybrid operating

    room or catheterization laboratory with high-definition fluoroscopic

    equipments and multiple monitors. As well, it is imperative that

    transesophageal echocardiography (TEE) or intracardiac echocardiography

    (ICE) be available to access ventricular, valvular functions and the annular

    size. In addition, TEE is an invaluable tool to help with the positioning of

    transcatheter valve

    stent prior to its

    deployment.

    Defining the

    implant angle,

    where the bases of

    all three aortic

    cusps reside on the

    same plane is

    crucial to a

    successful

    implant. An initial

    root aortogram

    performed with a 7

    French (F) pigtail

    catheter at the base of the non-coronary cusp at an angle of AP and caudal

    10o should guide the operator to define the optimal line of perpendicularity.

    Several imaging software systems, such as DynaCT, Innova HeartVision

    System and C-THV utilize 3-D rotational angiography to better define the

    aortic root anatomy and identify the line of perpendicularity. Preoperative

    multi-slice computer tomography (MSCT) can provide valuable

    information on annular size and implant angle.

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    SURGICAL ACCESS

    The left ventricular apex is located by placing the tip of a hemostat on the

    patient at the apex location as seen on fluoroscopy. This method has been

    found to be reproducible and more useful than palpation for the apex beat,

    particularly in patients of high body mass index. Preoperative CT guided or

    intra-operative surface echocardiography is used by some groups. Sixth

    intercostal space (ICS) is the most common access site, followed by 5th

    ICS. Over the previously determined

    location of the apex, a 3 cm incision is

    made. The incision is made over the

    top of the rib to avoid trauma to the

    neurovascular bundle. When it is

    possible, using the lower ICS is more convenient in terms of a straighter

    trajectory to the aortic valve. The left lung, as previously mentioned, does

    not usually interfere with the exposure of the left ventricular apex. A soft

    tissue retractor, Alexis Retractor is inserted into the incision to retract the

    soft tissue without spreading the ribs. This method greatly reduces post-

    operative pain.

    The pericardium is then incised and opened near the left ventricular apex

    and pericardial retraction sutures may aid further exposure. In cases where

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    the patient has a history of previous cardiac surgery, dissection of

    pericardial adhesions is avoided.

    As with all procedure, transapical

    TAVR has an Achilles heel and that is

    haemostatic control of the left

    ventricular apex. Particular care must

    be taken when placing two large

    pledgeted orthogonal mattress sutures

    using 3-0 MH polypropylene sutures

    to obtain full thickness of the left

    ventricular wall. Each of the two

    mattress sutures are snared and passed

    through tourniquets that can be

    tensioned at the time of sheath

    removal. The sutures are appropriately placed to allow space for the largest

    sheath, initially an Ascendra sheath with an internal diameter (ID) of 33 F

    sheath and more recently a smaller (24 F ID) Ascendra II Plus delivery

    system. The true apex should be avoided, as it is frequently thin and covered

    by adipose tissue. A bare spot lateral and cranial to the true apex should

    be used to avoid catastrophic ventricular rupture.

    Rapid ventricular pacing is required for the implantation of balloon-

    expandable prosthesis, in order to decrease forward flow during the

    valvuloplasty and valve deployment. One unipolar epicardial pacing wire is

    placed directly onto the left ventricle and another on patients chest wall.

    Alternatively, transvenous pacing lead can be implanted into the right

    ventricle. Pacing rate of

    140 to 200 beat per

    minute frequently results

    in 1:1 ventricular capture

    and lowers the pulse

    pressure and forward

    flow. The rapid pacing

    periods and episodes must be minimized to ensure hemodynamic stability,

    especially in patients with depressed left ventricular function and/or non-

    revascularized coronary artery disease.

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    Hemostasis of the apex is ensured prior to the administration of

    unfractionated heparin to achieve an activated clotting time of greater 250

    seconds. A 14-gauge Seldinger needle is positioned in the centre of the

    mattress sutures square and advanced to enter

    the chamber of the left ventricle. The angle of

    entry should be pointing toward the right

    shoulder, whereby crossing of the native aortic

    valve can be easily achieved. Correct placement

    can be confirmed by the visualization of bright

    red blood spurting with each ventricular

    contraction. If oxygenated blood does not spurt

    despite advancement of the needle, this suggests

    the needle may be in the interventricular septum. Also, the needle could be

    inadvertently embedded into the hypertrophied ventricular wall if the angle

    of introduction was too obtuse. If pulsatile venous blood is visualized, this

    is indicative that the septum has been crossed and the needle has passed into

    the right ventricle. Once oxygenated blood is visualized, a soft wire is used

    to cross the native aortic valve. A 7F sheath is introduced over the short

    wire using Seldinger technique across the AV. A 260 cm, 0.035- inch

    Amplatz extra stiff wire is exchanged and maneuvered down the descending

    thoracic aorta.

    BALLOON VALVULOPLASTY

    Balloon valvuloplasty can be performed with a 14 F Cook or the Ascendra

    sheath under rapid ventricular pacing. A 3 cm, 20 cc BAV balloon from

    Edwards LifeSciences is used for all cases

    regardless the size of the annulus. BAV

    facilitates the crossing of the stenotic AV and

    retrieval of the transcatheter valve if it is

    accidentally advanced past the native valve.

    Further, BAV improves the aortic valve area

    and allows flow around the valve stent during

    positioning, thus minimizing hemodynamic

    instability. BAV also rehearses the

    deployment steps, allowing synchronization

    of the team.

    Close observation of the movement of the calcified leaflets relative to the

    coronary Ostia during BAV may help to exclude patient with high-risk

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    anatomy for coronary occlusion. A root aortogram can be performed with

    an inflated balloon in situ to better define the structures.

    POSITIONING

    The Edwards SAPIEN balloon expandable transcatheter valve is

    constructed of trileaflet bovine pericardium on a metal stent. It is crimped

    onto the delivery balloon. The correct orientation of the transcatheter valve

    with the Dacron ring at the base of the valve on the ventricular outflow side

    and open stent on the aortic side must be ensured. After engaging the

    delivering system, the valve is advanced beyond the tip of the Ascendra

    sheath under fluoroscopic guidance.

    Withdrawal of the pusher catheter is

    then carried out. The SAPIEN valve

    is positioned within the native AV.

    The SAPIEN prosthesis is ideally

    placed 1/3 below the base of aortic

    sinuses, the bottom of the valve stent

    positioned ventricularly relative to

    the line of perpendicularity with the

    aide of repeat aortic root angiograms. TEE provides additional images that

    further refine the positioning. Aligning the ventricular end of the valve stent

    to the aorto-mitral fibrous curtain, the hinge point of the anterior leaflet

    of the mitral valve, confirms the ideal landing zone. If accurate positioning

    cannot be achieved due to brisk cardiac motion, rapid pacing with root

    injections may assist in positioning.

    DEPLOYMENT

    It is extremely important to ensure

    accurate positioning of the valve prior to

    its deployment to avoid malpositioing,

    embolization and significant perivalvular

    leak. Once acceptable positioning is

    confirmed using echocardiography and

    fluoroscopy, the pigtail catheter is

    withdrawn to the ascending aorta, the

    pacing protocol is again initiated and the

    valve is slowly deployed. During

    deployment, fine adjustment can be made

    to ensure optimal placement. Full

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    emptying of the inflation syringe and maintaining full pressure ensures

    symmetric deployment and prevents stent recoiling. The balloon is quickly

    deflated and pacing is ceased. The balloon is pulled back out of the valve

    stent into the delivery sheath, preventing interference with leaflet function.

    Once the valve is deployed, echocardiography reports on the stability,

    location and function of the valve stent, and the degree of perivalvular

    regurgitation. If valve position is satisfactory and more then moderate

    degree of perivalvular regurgitation exists, a second attempt with slight

    higher balloon inflation volume may be attempted. If the degree of central

    regurgitation through the valve is difficult to evaluate with the Amplatz wire

    across the valve, it too is withdrawn into sheath. Completion aortogram is

    seldom perform to minimize the dye load that may adversely effect renal

    function.

    SURGICAL CLOSURE

    With systolic pressure less than 100 mmHg, the delivery sheath is removed

    with snugging of the mattress sutures. Then

    the other orthogonal mattress suture is

    subsequently tied. Persistent hypertension can

    be controlled with ventricular pacing at a rate

    of 100 to 140 bpm. Any blood collections are

    aspirated from the left chest and local

    bupivacaine is injected into the intercostal

    muscles. A small-bore chest drainage tube

    brought out through a small stab wound is left

    behind in the left chest. The intercostal

    muscles are approximated and the skin closed

    with absorbable subcuticular suture.

    CONCLUSION

    Within the last decade, transcatheter aortic valve replacement (TAVR) has

    come from relative obscurity to become a procedure that is practiced at most

    major health centres worldwide and the technical details of this procedure

    have been described by many. The rapid adoption of TAVR in medical

    practice makes it one of the fastest therapeutic modalities incorporated and

    evaluated by randomized control trial. Transfemoral (TF-TAVR) retrograde

    and transapical (TA-TAVR) antegrade approaches were the most widely

    practiced. TA-TAVR is the preferred procedure where the peripheral access

  • 21

    is limited due to size, calcification and torturosity. TA-TAVR provides a

    more stable platform for TAVR, due to the more direct and shorter distance

    to the native aortic valve. Access via the subcalvian artery and ascending

    aorta are emerging to be viable alternatives. Procedural technique can be

    very important in high-risk patients and remains among the few modifiable

    factors. Therefore, it is worthwhile to describe the intricacies of the TA-

    TAVR approach, with the aid of photographs. The technique described is

    intended for transapical implantation of the SAPIEN transcatheter valve

    using the Ascendra delivery system.

  • 22

    FAQ

    WHAT CAUSES A FAILURE OF THE AORTIC VALVE?

    The aortic valve can not work for various reasons. For example, may be

    abnormal from birth (congenital aortic valve), or may become ill with age

    (acquired aortic valve disease).

    The most common congenital abnormality is a bicuspid aortic valve. The

    normal aortic valve has three flaps, but a bicuspid valve has only two.

    Therefore, it may not open or close completely. The bicuspid aortic valve is

    a common abnormality and is present 1-2% of the population. For frequency,

    it is the second leading cause of aortic disease that requires surgical

    treatment. such valves can function normally for years before they begin to

    be dysfunctional (stenotic and / or insufficient). People with a bicuspid

    aortic valve require antibiotic prophylaxis before interventions to the teeth

    but are not generally required other special precautions in addition to

    periodic monitoring by a cardiologist qualified. The most common cause of

    aortic disease that requires treatment surgery is called "senile aortic

    calcification." The valve is namely ruin with age. When a valve begins to

    deteriorate, the body calcium deposits on it for unknown reasons. The

    football narrows diameter and restricts the movement of the valve leaflets.

    This may hinder the valve opening (causing stenosis) or closing (causing

    insufficiency or regurgitation). Less common causes of valve disease aortic

    diseases of the ascending aorta, the main vessel blood that comes out from

    the heart and which carries the blood to the rest body: the aneurysm,

    dissection and Marfan syndrome.

    THERE ARE SIGNS OF A FAILURE OF THE ALARM AORTIC VALVE?

    Alteration of the aortic valve can cause a variety of symptoms, which

    include shortness of breath, chest pain (angina pectoris), dizziness and loss

    of consciousness (fainting). A valve stenosis causes an increase of the work

    that the heart has to do to pump blood around the body. a failure of the valve

    results in a return of blood in the heart after it has been pumped out. The

    heart muscle must therefore pump more blood to go forward, even one that

    is returned back. All of these conditions can cause symptoms super job of

    heart failure, such as shortness of breath, which at the beginning can be

    appreciated only under stress, but that later, with the progression of the

    disease, may also occur with activity light or at rest. Many patients can not

    sleep lying in bed or can wake up to the shortness of breath. Another sign

    of heart failure, which can occasionally appear, it is the swelling of the feet,

  • 23

    particularly evident in the late afternoon or evening, although other

    conditions such as varicose veins can cause such disorder. The super work

    that the heart has produced, can also cause pain angina pectoris or chest

    similar to the symptoms of a heart attack. It can be difficult to tell the

    difference between a disease and valvular stenosis of the blood vessels of

    the heart (arteries coronary arteries). The disease of the aortic valve can

    therefore cause dizziness, light-dizziness or even fainting periodicals.

    HOW DO I KNOW IF I HAVE TO BE AT WORK AORTIC VALVE?

    The decision to proceed with surgery should be taken with his medical team

    is usually composed of the cardiologist and by the cardiac surgeon. The His

    doctors probably base their recommendations on her symptoms and the

    results of some tests including an echocardiogram and cardiac

    catheterization times. An echocardiogram allows you to see an enlargement

    of the heart and can help to measure the degree of stenosis or insufficiency.

    A Cardiac catheterization provides similar information, but it can also

    identify possible stenosis of the coronary arteries.

    THERE ARE DIFFERENCES BETWEEN IMPLANTS AND MECHANICAL

    ORGANIC?

    Today there are numerous excellent prosthetic valves mechanical. Most

    surgeons have a preference for a specific valve in relation to some of the

    technical factors (for example: how they apply in the home, as did the suture

    ring, etc.). Although from the point of view of the patient is small the

    eventual difference between the various models. The main advantage of

    mechanical valves is their excellent lifespan. From a practical point of view,

    never wear. The main disadvantage is that there is a tendency of blood to

    clot on all mechanical valves. Consequently, patients with such valves must

    take anticoagulants or "blood thinners" for the rest of their lives. So there is

    a small but well-defined risk of blood clotting, which can cause the

    prosthesis stroke. There is a large variety of biological valves that can be

    used to replace a diseased valve. They all have in common a reduced risk

    of formation of blood clots, but all are less durable than mechanical valves.

    Past a certain time, all will be consumed. The choices in this category

    include the xenograft, valves made from animal tissue (most of the times of

    pig aortic valves or valves "built" with pericardium cattle), the homograft

    or allograft valves prepared from cadavers human, and l '"pulmonary

    autograft", a self transplant, their valve moved from the pulmonary artery

    on the right side of the heart, the seat Aortic on the left side.

  • 24

    The decision on the type of valve to be used should be taken into accordance

    with his cardiologist and cardiac surgeon. Ultimately the choice depend on

    the preferences of the patient, his lifestyle and individual risk determined

    by age and other medical conditions.

    HOW IS THE SURGERY PERFORMED?

    The replacement of the aortic valve is an intervention that is performed only

    by the cardiac surgeon. Is performed under general anesthesia general.

    Before being asleep are inserted cannuline in certain veins of the arm, for

    the infusion of drugs, and in artery for continuous measurement of blood

    pressure. The traditional technique requires a longitudinal aperture

    (vertical) of the anterior wall of the chest through the breastbone that is cut

    into two parts. This incision is called a sternotomy vertical midline. Through

    this opening, the surgeon can see all your heart and the ascending aorta. The

    surgery requires that the patient is connected to the machine heart-lung. To

    do this, two cannulas are inserted, one in the the upper part of the ascending

    aorta and the right atrium. They carry the blood from the patient to the

    machine, where it is enriched with oxygen, and vice versa. Started the extra

    corporeal circulation, the heart can be stopped with a special blend of

    chemicals call cardioplegia.

    At this point, the aorta is opened, the diseased valve removed and the His

    place was inserted a prosthesis (mechanical or biological). and then the

    aorta is closed. Just receive back the blood, the heart begins spontaneously

    to contract. The patient can then be removed from the machine.

    WHY I NEED SURGERY?

    The aortic valve is the valve out of the left side of the heart. It opens during

    systole (when the ventricle contracts and pushes blood into the aorta and the

    rest of the body). When the aortic valve is too narrow (stenotic), the

    ventricle must work hard to push the blood around the body. This extra-

    work consumes considerable amounts of energy and ultimately requires a

    blood flow in more to nourish the heart itself. If there is a sufficient arrival

    of the blood, the heart becomes ischemic with resulting in anginal chest pain.

    Aortic stenosis is usually progressive and gets worse with time. When the

    valve becomes very narrow, the heart has to work harder and harder until

    that an certain point no longer able to compensate. Appear as episodes of

    low blood pressure (hypotension crises), syncope (loss of consciousness),

    congestion and pulmonary edema. Even when the aortic valve is insufficient

    (loses), the heart works harder and you create the same problems. The

  • 25

    ventricle must pump more blood with each contraction to produce the same

    thrown forward. This creates a condition called overload volume. The heart

    can compensate for this overload for many months or even years, provided

    that the failure to develop slowly. By the time the heart starts to break down

    and appear to lack breath and weakness. The possible benefits could be the

    disappearance of the anginal symptoms, heart failure and syncope. The

    chances of successful treatment in the absence of complications, are 95%

    (failure rate of 5%).

    ALTERNATIVES TO SURGERY

    Are there alternatives to surgical treatment and that the facility valvular

    trans-apical (TA-TAVI), namely the implantation of an endoprosthesis tube

    through a cannulation of the apex of the heart with a mini access chest or

    with the introduction of an endoprosthesis valve through the femoral artery

    in the groin catheterization. These methods, however, at present, are

    indicated only for patients with severe impairment of the general condition

    or patients terminals, that is not amenable to conventional treatment.

    RESULTS OF TREATMENT FAILURE

    The predictable outcome of not treating are worsening progressive heart

    failure and angina with an increase functional limitations, increased

    frequency of episodes syncopal and the possibility of cardiac death.

    WHAT 'THE RISK OF SURGERY?

    The risk cardiac surgery depends on the conditions, the general conditions,

    the presence of other comorbidities and functional status of the major organs

    and body systems. Among these are:

    circulatory failure can not be controlled with medication, for which

    must resort to mechanical systems support.

    sudden occlusion of a coronary by-pass with the eventual need for a

    new surgery;

    malfunction of prosthetic valve;

    heart attack directly associated with the transaction;

    paralysis (temporary or permanent) in the arms and / or legs (for

    example due to an insufficient blood supply);

    complications of the gastro-intestinal tract;

  • 26

    cerebral complications (results in impaired speech and movements

    up to coma) caused by a blood supply defective due to poor

    circulation or blood clots;

    thrombosis, embolism (blood clots and subsequent vessel

    occlusion);

    bleeding: from surgical sutures and / or from abnormal coagulation

    of the blood;

    infection and suppuration intractable arrhythmias or forms that may

    require further medicines, or the implantation of a pacemaker;

    Pouring liquid into the pleural cavity and / or in the pericardium,

    which must be drained;

    shortness of breath due to paralysis of the diaphragm;

    broncho-pneumonic complications.

    WHAT WILL MY CONDITION AFTER REPLACING AORTIC VALVE?

    After successful aortic valve replacement, patients can expect to return

    quickly to the conditions preoperative. As a result of their condition should

    definitely improve. The anticoagulant ("blood thinning") with a drug

    (Sintrom or Coumadin) should be prescribed for 2-3 months in patients with

    biological prosthesis, for the whole life in those with valve mechanics.

    When surgical wounds will be healed, there will be few or no restrictions

    on its activity.

  • 27

    ARTICLE 1 SURGICAL TREATMENT OF AORTIC VALVE ENDOCARDITIS

    ABSTRACT

    Endocarditis of the aortic valve is a surgical

    operation that is applied since 1965 This article

    presents a retrospective study of all the operations

    and the results obtained in 174 aortic valve

    replacements affected by endocarditis, in 26 years

    of business in Kartal Kosuyolu Heart and Research

    Hospital in Istanbul. 282 interventions were

    performed, of which 230 have been replacements of aortic valves (with and

    without endocarditis). The hospital mortality was 15.5% (27 cases). The

    survival rate for 10-15 years after surgery was equal to 74.6 + 3.7% (in

    patients with a reduced cardiac output) and to 61.1 + 10.3% (for patients

    who have had a cardiac arrest). This study found that the operation has a

    significant mortality and risk factors are: emergency operations, female

    gender, renal failure and reduced cardiac output. The risk of recurrence and

    the need for new operations is low.

    Kartal Kosuyolu Heart and Research Hospital, Istanbul - Turkey

  • 28

    ARTICLE 2 - AORTIC STIFFNESS IS AN INDICATOR OF COGNITIVE DYSFUNCTION

    ABSTRACT

    This article presents a study on patients had cognitive dysfunction, after

    operation of the AVR (Aortic Valve Replacement) for Aortic Stenosis (AS).

    These disorders are frequent in patients operated on at the aortic valve due

    to the risks associated with the surgery, which are: the systemic

    inflammatory response syndrome, hypoperfusion, microembolization. Even

    in patients undergoing "successful interventions" were presented

    postoperative cognitive problems. In the face of these data, it was decided

    to evaluate whether aortic stiffness is related to cognitive dysfunction in

    patients undergoing surgery for aortic

    stenosis. The aortic pulse wave

    velocity (PWV) was used as a

    measure of aortic stiffness and

    cognitive function was assessed using the computerized Cambridge

    Neuropsychological Test Automated Battery (Cantab). Patients with normal

    PWV were: higher mental retardation, visual sustained attention and

    executive function comparable to patients with high PWV. The immediate

    memory and decision-making were similar in the two groups. After surgery,

    the improvement of cognitive function was more pronounced in patients

    with higher PWV compared to patients with normal PWV. The conclusion

    is that the intervention AVR can not be associated with an effect on

    cognitive process. The PWV could be useful as an additional marker of

    cognitive function before and after surgery for AS.

    St. Mary's Hospital, London - England

  • 29

    ARTICLE 3 FAST-IMPLANTABLE AORTIC VALVE

    ABSTRACT

    This article presents a new type of valve that can be implanted during an

    intervention with concomitant mitral valve replacement. Two bioprosthetic

    heart valves may interfere for their design or for space dimensions. With the

    new valve Intuity (who has a stent under the ring) there is no interference

    with an existing mitral valve. The valve

    has been tested on pigs before and then

    after signing the informed consent, two

    patients. The first was a woman of 82 years

    of which have been replaced both valves,

    the aortic and mitral stenosis, without

    interference observed on chest

    radiographs. The second case was also

    replaced both valves via two venous grafts

    without presenting postoperative

    interference. In the light of these results it

    has been claimed that the valve Intuity is

    much faster to implant (does not need all the stitches of the prosthesis

    standard) and its plant does not increase the risk of displacement of the

    mitral valve. The time to plant is 8-1o minutes and this significantly lowers

    the probability of an ischemic cardiac arrest.

    University of Lausanne, Lausanne - Switzerland

  • 30

    ARTICLE 4 - RETROGRADE CARDIOPLEGIA ADMINISTRATION

    ABSTRACT

    This article emphasizes the importance of the administration of retrograde

    cardioplegia in a particular case. The Routes of administration of

    cardioplegia are three:

    Aortic Bulb: seat of election, with the exception of aortic insufficiency

    because refluirebbe in the ventricle;

    Coronary Osti: using this access route in the case of aortic

    insufficiency;

    Breast coronary artery (retrograde): you use this access route even

    when the coronary ostia are obstructed or otherwise there is a multi-

    axial obstructive coronary artery disease.

    The coronary sinus can be reached directly with a video-assisted

    cannulation and at pressures lower than 40 mmHg, or indirectly through the

    right atrium (little used because it would cause excessive dilation of the

    atrium or the right ventricle).

    In this case the patient, 66, had been admitted into the local clinic for the

    treatment of aortic stenosis. Angiography showed variations in coronary

    narrowing. At the same time it was found that the anterior branch had a

    separate start dall'ostio descending artery. Because of the complex

    anatomical situation of the aortic valve was decided to change the strategy

    to protect the myocardium against ischemia. The procedure was performed

    in moderate hypothermia at 32 C and the heart was stopped with cold

    retrograde cardioplegia. The result showed no postoperative ischemic

    damage in the patient.

    Akademicki Szpital Kliniczny, Wrocaw - Poland

  • 31

    ARTICLE 5 MID-TERM RESULTS FOR AORTIC ROOF REPLACEMENT

    ABSTRACT

    This article shows the results of 201 interventions for aortic root

    replacement with biological prosthesis and stent. The patients had a mean

    age of 66 years old and had

    undergone surgery for:

    annuloectasia or aortic aneurysm

    of the ascending aorta with

    concomitant valve endocarditis.

    The hospital mortality was 4.5%

    and the rate of cardiac mortality

    related to the intervention, after

    1-5 years, 3-6%. No patient

    presented over the years

    thromboembolic events. The 1%

    of patients presented a slight

    structural deterioration of the

    valve without clinical symptoms.

    In light of these results it can be stated that in the medium term, the aortic

    root replacement with biological prosthesis self-assembling is interesting.

    The hemodynamic results are excellent and the need to redo the operation

    is remarkably low. The long-term results will clarify fully the real risks of

    surgery.

    University Hospital Berne, Berne - Switzerland

  • 32

    ARTICLE 6 PERCUTANEOUS AORTIC VALVE REPLACEMENT

    ABSTRACT

    To be eligible for the TAVR is a

    variable number of patients. 30% of

    patients with severe aortic stenosis

    who require appropriate action, not

    receive it. Given the aging of the

    global population, patients who will

    need TAVR will be more and more.

    Clearly, the choice between TAVR

    and AVRbyOS will be dictated mainly by the costs and organization of each

    country. On the one hand you have a very high risk of doing AVSbyOS in

    cases of emergency and the other with the TAVR is likely a left bundle

    branch block. In addition, patients who need a pacemaker after the operation

    are those made with TAVR; the same ones who have the most frequent

    postoperative stroke. Instead, ischemic defects are more frequent in patients

    operated with AVRbyOS because the aorta is manipulated. It can be

    concluded that on both sides there are risks to consider but lacks a

    randomized clinical trial to know the follow-up of patients 10-15 years after

    surgery. When these data will be collected you will have the chance to make

    a change of direction towards the TAVR intervention that is less invasive

    and with fewer postoperative complications.

    Hospital Universitario Fundacin Favaloro - Argentina

  • 33

    BIBLIOGRAPHY

    Autori vari, Trattato di Anatomia Umana, Volume I e II, Edizione 2009,

    Edi-ermes.

    Guyton A. e Hall J. E., Fisiologia Medica, Edizione 2010, Elsevier.

    Nelson D. L. e Cox M. M., I principi di Biochimica di Lehninger, Edizione

    2010, Zanichelli.

    Andreoli, Carpenter, Griggs, Benjamin, Cecil Essential of Medicine,

    Edizione 2007, Elsevier.

    SITOGRAPHY

    PUBMED:

    http://www.ncbi.nlm.nih.gov/pubmed

    NEW ENGLAND JOURNAL OF MEDICINE:

    http://www.nejm.org

    CARDIO EXPERT CHANNEL:

    http://www.youtube.com/channel/UCeaM0YzToLcfeCiBkJQCqhA

    http://www.ucl.com

    http://www.cardiochirurgia.org/sva.html

    http://my.clevelandclinic.org/services/heart/disorders/valvetreatment/aort

    icvalvesurgery

    http://www.ncbi.nlm.nih.gov/pubmedhttp://www.youtube.com/channel/UCeaM0YzToLcfeCiBkJQCqhAhttp://www.ucl.com/http://www.cardiochirurgia.org/sva.htmlhttp://my.clevelandclinic.org/services/heart/disorders/valvetreatment/aorticvalvesurgeryhttp://my.clevelandclinic.org/services/heart/disorders/valvetreatment/aorticvalvesurgery