Valvulopathies

Content

Introduction

Valvulopathies, or diseases of the heart valves, include several diseases characterized by a malfunction in the control of blood flow, due to damage or defect, of one of the four heart valves:

  • mitral, controls the flow of blood between the atrium and the ventricle of the left side of the heart
  • aorta, controls the flow of blood between the left ventricle and the aorta
  • tricuspid, controls the flow of blood between the atrium and the ventricle of the right side of the heart
  • pulmonary, controls the flow of blood from the right ventricle to the pulmonary artery

The control of blood flow is exercised through the opening and closing of the valves which occurs mechanically as a result of the difference in pressure produced by the quantity of blood in the 4 chambers of the heart (left and right atrium, left and right ventricle), in the " aorta and pulmonary arteries.

The amount of blood varies as a result of the relaxation (diastole) and contraction (systole) activity of the atria and ventricles. When the atria relax, the ventricles contract and vice versa.

Diastole and systole are the phases of a continuous cycle, without interruptions: the cardiac cycle. They follow each other rhythmically but are not completely separate:

  • early stage of ventricular diastole, relaxation of the ventricles begins, which passively fill with blood. It is phase 1 of the complete cycle
  • contraction of the atria (atrial systole), which push "extra blood into the ventricles. This is stage 2 of the full cycle."
  • contraction of the ventricles and closure of the atrioventricular valves (mitral and tricuspid). It is phase 3 of the complete cycle. The amount of blood that the ventricles can pump with each contraction is referred to as systolic range
  • opening of the semilunar valves (aortic and pulmonary), is phase 4 of the complete cycle. The blood flows to the aorta and lungs, the amount of blood that is expelled in one minute is called cardiac output
  • relaxation of the ventricles and closure of the semilunar valves, is phase 5 of the complete cycle. The pressure inside the ventricles decreases, the semilunar valves close and a new cardiac cycle begins again

When the pressure in the ventricles decreases and falls further than that of the atria, the atrioventricular valves reopen and the ventricles are flooded with blood again, with a defined rapid filling (rapid or passive ventricular filling) equivalent to 2/3 of the quantity of liquid that the heart is able to accept, the last third will be added with the contraction of the atria (atrial systole).

The rapid movement of blood (acceleration), or its arrest (deceleration), gives rise to noises, tones in medical language, which can be heard by placing an ear on the chest or with the instrument that detects the sounds of the deeper organs of the chest (stethoscope).

In each cardiac cycle it is possible to hear four tones, of which only the first and second are audible with the stethoscope:

  • first tone, marks the beginning of ventricular systole, is long, severe (dark) and is produced essentially by the movement of the atrioventricular valve flaps which are tensed, by their closure and by the movement of the muscle fibers of the ventricles which contract
  • second tone, marks the end of systole, is short, acute (high) and is produced by the semilunar valves that are sharply stretched to close
  • third tone, is produced by the rapid filling of the ventricle, in the initial phase of diastole
  • fourth tone, is determined by the contraction of the atrium

Depending on the type of damage, or defect, of the valves, problems may arise in their opening which may be partial. In this case, in medical terms, we are talking about stenosis. If the defect, on the other hand, concerns the closure, which may be imperfect, we speak of insufficiency.

There stenosis it consists of a narrowing (which obstructs the passage of blood) of the opening of the valve.

L"insufficiency it consists of an imperfect closure of the valve which causes the blood to rise again (regurgitation): if the valve does not close hermetically, the blood tends to rise, with a backward trend compared to the natural path.

There stenosis and the "insufficiency they can be isolated or combined (steno-insufficiency). They can concern a single valve or several valves at the same time (compound valvulopathies).

The main valvulopathies are:

  • mitral insufficiency
  • mitral stenosis
  • aortic insufficiency
  • aortic stenosis
  • tricuspid insufficiency
  • tricuspid stenosis
  • pulmonary insufficiency
  • pulmonary stenosis

They may already be present at birth (congenital) or, more frequently, develop during life (acquired). Their evolution is in most cases very slow except when the disease arises suddenly, following trauma, myocardial infarction, endocarditis, rupture of tendon cords.

The valves of the left sector of the heart (mitral and aorta) are more affected than those of the right sector (tricuspid and pulmonary, rarely affected and, generally, due to an "anomaly present at birth), since they are subjected to greater pressure.

Symptoms

Often there are no signs (symptoms) until the malfunctioning of the valves causes significant damage to the functioning of the heart. The progress of the disease is very slow and conditions can worsen even after decades but in the last phase the aggravation can be very rapid. For this reason it is advisable, when the disease has already been identified, to respect the scheduled medical checks.

The valves most frequently affected are the mitral and aorta. The most common disturbance caused by both is "breathlessness" (dyspnea), initially felt only during physical activity, later also at rest.

In aortic stenosis, chest pains may occur and even short-term fainting (syncopes) may occur.

Mitral diseases are often related to arrhythmia problems that can generate other complications and reduce the heart's ability to function.

In general, feeling older than your age could be a sign of a heart or valve problem.

Causes

Diseases of the valves of the heart (valvulopathies) may already be present at birth (congenital), or they may develop later in life (acquired).

In the first case they are caused by anomalies of the structures of the heart that go back to the development phase of the embryo, often associated with specific syndromes. The most common are aortic bicuspidia and mitral prolapse.

In the second case they can derive from:

  • degeneration and calcification of the valve tissue, with consequent narrowing of the valve, mostly due to wear, more frequent in old age
  • infections and inflammations (infectious endocarditis, rheumatic disease), caused by viruses, bacteria, toxic substances, drugs injected intravenously
  • diseases, such as hypertension and atherosclerosis
  • acute myocardial infarction and heart failure, which at first can only dilate the heart, later also the valve ring to cause its insufficiency
  • autoimmune diseases, such as lupus
  • some medications
  • radiotherapy
  • trauma, very rarely

The risk of infection mainly concerns valves with malformations or damage.

In the past, the most frequent cause of heart valve disease was rheumatic disease, triggered by the complication of a "streptococcal infection of the pharynx or tonsils.

Streptococcus, in fact, after a few weeks can pass from the throat into the bloodstream (bacteremia), reach the heart and implant itself in the valve flaps which, without effective antibiotic treatment, could be damaged even after many years of infection. Migration can also occur following surgery, for example to remove the tonsils or adenoids.

Today, considering the lengthening of life, the most frequent cause of valvulopathy is degeneration caused by wear resulting from aging. It mainly affects the aortic valve.

The use of antibiotics, in fact, has reduced cases of infections; hypertensive and ischemic heart disease and tumor diseases, the main causes of death in the Western world, are better treated and therefore the duration of life is significantly increased.

Diagnosis

The ability, on the part of the doctor, to listen and evaluate the noises produced by the movement of blood, with its accelerations and decelerations, and by the opening and closing of the valves that regulate it, undoubtedly constitutes the starting point for discovering the disease.

Heart valve diseases (valvulopathies), in fact, modify both the tones cardiac, in intensity, timbre, and rhythm, both the flow of blood that from laminar becomes turbulent, in other words it no longer flows like many parallel plates but in a confused way.

Here are some examples of alterations in the tones:

  • first tone, long and severe (dark), it is weaker in aortic insufficiency, while more pronounced in mitral stenosis
  • second tone, shorter, acute (tall) and dry, is weaker in aortic stenosis
  • third tone, normal in children and adolescents, in adults it can also be a sign of an overload of the ventricles
  • fourth tone (atrial tone) rare under normal conditions, occurs in case of ventricular overload and atrioventricular block
  • gallop (noise similar to the gallop of the horse, characterized by three times), is an indication of heart failure

The turbulent flow produces new defined noises puffs, however, not all valvulopathies generate murmurs and not all murmurs are indicative of valvulopathies:

  • pregnancy, the normal (physiological) increase in blood circulation can generate murmurs that disappear after delivery
  • sportsmen, murmurs may originate from increased cardiac output
  • babies and children, murmurs can result from the rapid passage of blood through the small structures of the heart. These puffs are called innocent and disappear with growth; in some cases they are related to valve defects, already present at birth (congenital), are considered benign and medically negligible
  • old age, murmurs are often due to a natural (physiological) hardening of the valves and tissues, without necessarily being an indication of valvular and, more generally, heart disease

The reference exam to confirm or exclude valve diseases is the echocardiogram, a non-invasive exam that allows you to see the heart as it moves on a monitor.

The electrocardiogram (ECG), on the other hand, is useful for signaling the repercussions that diseases of the valves can have on the transmission of the electrical impulse and therefore on the presence of any arrhythmias of which the most frequent is atrial fibrillation.

Other tests that may be required, if the echocardiogram is not clear and sufficiently reliable, are cardiac magnetic resonance and cardiac CT, which provide complementary information to the echocardiographic examination but with a very accurate level of image definition. Cardiac catheterization is rarely used: a small catheter is inserted through a blood vessel in the arm or groin until it reaches the heart, a colored substance (contrast agent) is released, blood flow is observed as it passes the valves and the pressures inside the heart are measured.

Therapy

Commonly, heart valve disease in its early stages and for many years does not require any drug therapy.

Antibiotics are used in people with known valvular disease to reduce the risk of infections in other parts of the body reaching the heart, for example, infections of the tonsils, adenoids, pharynx, mucous membranes, skin (skin); the administration of antibiotics is essential during dental extractions, biopsies, surgery and to avoid new episodes of rheumatic valve disease.

Vasodilator drugs, diuretics, cardiokinetics, beta-blockers, and antiarrhythmics are prescribed at different stages of the disease when valve malfunction compromises the heart's ability to function; or, to stabilize health conditions after a sudden episode, before surgery.

Surgery is the definitive solution for the most severe forms. In general, when valvular disease worsens, surgery is done before it causes irreversible heart failure.

The traditional surgery can last from 2 to 5 hours, requires a "general anesthesia," an incision of the sternum (replaced, when possible, with a small incision of about 5-7 cm at the level of the II-III or IV space intercostal properly called mini-thoracotomy, much less invasive), the use of a heart-lung machine to pump blood since the heart is stopped during surgery, replacement or repair of the diseased valve; recovery requires 2/3 months.

Alternatively, especially in the elderly who are at high risk of facing traditional surgery, "endoscopic surgery" can be used. It is a set of techniques that use a catheter to reach the valve to be repaired, or to be replaced, through a simple puncture in the artery of the arm (radial artery) or in that of the leg (femoral artery). This technique is used to balloon valvoplasty, for the repair of a stenotic valve, or for implantation of the aortic valve via transcatheter (TAVI), when it is necessary to replace it. Endoscopic surgery can also be used for the treatment of mitral insufficiency, by means of femoral implantation of one or more mitral clips and, more recently, also for the treatment of tricuspid insufficiency.

Whenever possible, it is preferable to repair the valve, otherwise it is necessary to replace it with biological valves (of a pig or a cow or taken from a corpse) or mechanical.

The choice of one or the other type of valve depends on many factors such as, for example, the valve to be replaced, the age, the degree of physical activity practiced, the lifestyle choices of the person concerned (for example, a "possible" pregnancy).

Biological valves last less (in any case many years) but offer the advantage of requiring anticoagulant therapy, only for a few months; mechanical valves are much more durable but require anticoagulant therapy for life, a condition not compatible, for example, with a pregnancy.

Prevention

For heart valve diseases (valvulopathies) there is no real prevention. In general, as with other cardiovascular diseases, it is advisable:

  • maintain a healthy weight
  • not smoking
  • doing physical activity
  • keep blood pressure below normal levels
  • follow a healthy and balanced diet

For both valvulopathies present at birth (congenital) and for most of those acquired, it is not possible to implement specific prevention measures even to slow down their deterioration over time. However, once the disease is discovered, it is important to follow the checks planned by the doctor and to intervene promptly with adequate surgical measures, as soon as the conditions require it, to avoid complications.

The use of antibiotics has considerably reduced both the cases of valvulopathies resulting from infections and inflammation (endocarditis) caused by bacteria, and the appearance of repeated episodes of rheumatic disease.

Complications

When valve diseases (valvulopathies) originate from narrowing (stenosis), the heart, after having put in place a series of mechanisms (myocardial hypertrophy) to cope with the increase in pressure necessary to overcome the obstacle (stenosis), goes meeting with decompensation.

When, on the other hand, they originate from an imperfect closure (insufficiency), the chambers receive a greater quantity of blood than the capacity to accept it and the heart expands excessively to the point that, no longer able to contract, the quantity of blood expelled from the ventricles (cardiac output) decreases dramatically and blood stagnation occurs in the lungs (pulmonary edema), liver (hepatomegaly), limbs.

Living with

Thanks to the development of techniques for the detection of heart valve diseases and increasingly sophisticated surgical practices, the quality of life of those affected has significantly improved.

In the initial phase and for a long time, in the absence of disorders (symptoms), these diseases do not affect in any way the performance of daily activities. Therefore, no form of therapy is recommended.

Useful tips to follow are:

  • antibiotic therapy, in the case of complex dental treatments, for example at the root of the tooth, invasive examinations such as a biopsy, surgery or in case of infections, because more easily the bacteria could pass from the infected site to the tissues of the heart
  • brush your teeth, immediately after meals
  • regular dental check-ups

When the conditions worsen and it is necessary to resort to surgery, the situation changes in relation to the type of intervention.

Minimally invasive and reparative surgery is characterized by short times both in the duration of the therapies required, and in the recovery of a completely normal life like the one before the disease.

The implantation of a valve involves therapy with anticoagulant drugs to avoid the risk of thrombus formation. In fact, the blood coagulation system tends to cover the artificial valve with clots (thrombi) to integrate it into the body and the natural movement of the valve could send them into circulation and cause an "embolism.In the case of biological valves (the tissues are of animal origin), anticoagulant therapy is only necessary for a short period, while for mechanical valves for life.

Bibliography

Ministry of Health. Heart valve disease

In-depth link

University of Catania. School "Faculty of Medicine". Valvulopathies

Canova GB, Cardiac valvulopathy and nursing care. Nurse 24 + it 

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