Mitral stenosis is a heart condition which consists of mitral valve thickening which becomes rigid, it cannot be fully opened.
This condition can cause various complications such as cardiac arrhythmias (abnormal electrical activity that are perceived by the patient as heart palpitations), heart failure, pulmonary edema or stroke (through the formation of emboli in the left atrium, with their subsequent mobilization).
Anatomy and physiology of the mitral valve
The mitral valve is one of the four heart valves. It is a ring of fibrous tissue, which separates the left atrium from the left ventricle (left heart chambers), which pumps blood to the rest of the body. A healthy mitral valve has two small valves (bicuspid) that open when the blood passes to the ventricle.
Mitral stenosis is characterized by thickening, fibrosis and hardening of the mitral annulus, such as mitral orifice narrows and blood cannot pass by to the left ventricle. The consequence of this is the accumulation of blood in the downstream, in the left atrium and then to the lungs (heart failure and pulmonary edema).
Mitral Stenosis Causes
Most cases of mitral stenosis are considered late complications of rheumatic fever (a disorder which occurs most frequently in children). However, most often strep infection is asymptomatic and thereby properly left untreated (treatment consist in eradication of infection with penicillin). 14 days after the onset of infection a series of immune complexes are formed with high affinity for connective tissue (like heart valves – M protein). Mitral stenosis occurs after a free interval of 10-20 years from initial rheumatic attack, but is often asymptomatic in the early stages.
The incidence of rheumatic mitral stenosis decreased in recent years due to the identification and proper treatment of beta-hemolytic streptococci infection. However, the condition is quite common in cold and wet climates.
There are other rare causes, possibly causing mitral stenosis, of which we can include:
Congenital heart malformations (congenital mitral stenosis) – are diagnosed in childhood and in adolescence and can cause serious complications;
Bacterial endocarditis (bacterial infection of the heart valves);
Myocarditis (inflammation or infection of the heart muscle);
Association with certain diseases: systemic lupus erythematosus, rheumatoid arthritis, carcinoid syndrome, etc.;
Atrial myxoma (benign tumor of the atrial muscle) which can cause blockage of the mitral valve orifice.
Mitral Stenosis Symptoms
Mitral stenosis is a chronic disease. As mentioned previously, symptoms develop after a latent period of about 10-20 years of initial rheumatic attack (cases were reported with a latency period of 40 years). Early symptoms are relatively mild, nonspecific, being easily confused with other cardiac conditions.
In advanced stages, when the stenosis is severe there appear more serious symptoms:
dyspnea (breathlessness), occurs when the stenosis is severe and blood escapes from the left atrium through the pulmonary veins and then to the lungs (pulmonary edema), which alters the physiological gas exchange, also left atrial overload may alter its electrical activity and can lead to cardiac arrhythmias, particularly atrial fibrillation, ventricular arrhythmias can aggravate pulmonary edema (acute pulmonary edema is a medical emergency and life-threatening);
marked fatigue (tiredness), appears gradually to greater efforts, then increasingly smaller efforts, eventually becoming permanently at rest, fatigue occurs due to insufficient oxygenation of tissues;
heart palpitations (abnormal heart beats) occur because the left atrium is overloaded (atrial fibrillation is the most common arrhythmia in mitral stenosis and can cause serious complications such as systemic embolisms);
Hemoptysis (coughing blood), occurs with aggravation of the pulmonary edema, when pressure increases in the pulmonary veins.
There are certain aggravating factors of mitral stenosis:
Intercurrent diseases and infections;
Symptoms of mitral stenosis are installed gradually in parallel with the grade of stenosis.
When compensatory mechanisms are overcome, heart failure appears:
dyspnea at effort, dyspnea of rest;
Paroxysmal nocturnal dyspnea (shortness of breath occurs at night and wakes the patient from sleep);
acute pulmonary edema (which is a medical emergency and requires urgent treatment);
Aggravation of ischemic heart disease with the occurrence of acute myocardial infarction.
Among the less common symptoms in mitral stenosis, we mention:
Ortner’s syndrome (paralysis of the vocal cords);
Dysphagia (difficulty swallowing);
Retrosternal chest pain;
Perioral and peripheral cyanosis;
Mitral facies (cheekbones with red-purple skin)
Mitral stenosis risk factors
Of the risk factors for the occurrence of mitral stenosis we can include:
History of rheumatic fever (acute rheumatic fever), secondary pharyngeal streptococcal infections which unfortunately remains undiagnosed and therefore untreated, so that such persons do not know that they are likely to develop mitral stenosis over time;
Old age – because heart valves become stiff;
Females: more than 70% of patients with mitral stenosis are women.
Among the rarer causes that can lead to mitral stenosis we mention Marfan syndrome, a genetic disorder that can cause tissue calcifications, fibrosis of the mitral valve and therefore mitral stenosis. We must mention however that in this case the mitral ring becomes in time lax and can lead to mitral regurgitation.
There are no specific methods to prevent mitral stenosis. However there are some methods that can slow down the progression and complications.
Mitral Stenosis Investigations
As we discussed previously, mitral stenosis is a chronic condition, relatively asymptomatic in the early stages and therefore difficult to diagnose. Diagnosis is established in most cases when appears moderate to severe symptoms or complications.
Anamnesis and medical history
Anamnesis and personal medical history evaluation are important because it can highlight the following:
Positive history of rheumatic fever (strep throat or pharyngeal tonsils in childhood);
Bacterial endocarditis (infection of the heart valves and chambers), a condition common among people with mitral stenosis;
Congenital heart defects (structural abnormalities of the heart, present at birth);
Symptoms that may indicate heart failure (dyspnea, fatigue, peripheral edema, cyanosis).
General clinical examination is very important and may reveal the following:
Cardiac auscultation may reveal a noise (snap) due to slow opening of stenosed mitral valve, besides the two physiological heart sounds. Cardiac auscultation is difficult to perform among obese individuals, those with other heart diseases or in the elderly;
Presence of bilateral peripheral edema, especially in the ankle, with warm skin, slightly cyanotic;
The present of hepatojugular reflux ( blood outpouring in the veins of the neck, secondary to liver stasis);
Lung auscultation may reveal the present of hyperemia rales, at the level of lung bases (pulmonary edema);
Recognition of mitral facies (red purple cheeks).
Mitral Stenosis Echocardiography
Echocardiography is a diagnostic imaging method of cardio-vascular diseases. This method uses ultrasounds, which carries an echo (sonogram) of the heart and can reveal the structural or functional changes. Echocardiography can evaluate also the severity of mitral stenosis or the presence of some complications such as atrial thrombosis.
Transesophageal echocardiography is a performance method, which consists in placing in the esophagus a transducer that emits ultrasounds (which is anatomically located near the heart) and can provide important information on the morphology and function of the heart and mitral valve. This method is used to evaluate the anatomy and physiology of mitral valve after surgical correction (valvuloplasty).
Echocardiography may dignify the following:
Closing, respectively opening of mitral valve;
Measuring the mitral valve: normally, the mitral orifice measures between 4 and 5 cm2, mitral stenosis occurs when the whole diameter is less than 4 cm2, however, the symptoms of the disease only occur when the diameter of the mitral valve is about 2 cm2; corrective surgery is indicated when it is identified a stenosis of 1.5 cm2;
Indirect measurement of intra atrial pressure (due to underlying stenosis), it is an important indicator of the severity of mitral stenosis;
The morphological and functional evaluation of the left ventricle (wall dimensions, ejection fraction evaluation );
Measuring the pressure in the pulmonary arteries: pulmonary pressure above 20 mm Hg is indicating a decompensation of heart function;
Measurement of the left atrium dimensions and identifying thrombus at this level (very important especially among people with atrial fibrillation);
The evaluation of the function of other heart valves.
Echocardiography is the most effective method for periodic evaluation of cardiac function. Cardiac sonograms can identify complications associated with mitral stenosis and help to establish the correct therapeutic algorithm.
Electrocardiography can evaluate:
Sinus rhythm of the heart and heart rate;
Evaluation of the atria and ventricles (especially the left atrium);
Identification of coronary artery disease or myocardial infarction (which may aggravate the mitral stenosis).
Radioscopy or chest radiography may reveal changes due to mitral stenosis (left atrial enlargement) or changes in the lung parenchyma (interstitial edema, especially in the hilum and lung bases). Rarely can be seen calcification of cardiac valves.
We must specify that the ECG and pulmonary radiography identify pathological changes only in case mitral stenosis complications: cardiomegaly (enlargement of the heart), hypertrophy (thickening of the heart walls), and the presence of arrhythmias or ischemia (inadequate blood supply to the heart).
Cardiac catheterization is an investigation usually used before surgery for correction of mitral stenosis and involves inserting a catheter through the femoral vein or artery up to the heart. It measures the pressure of overlying stenosis (left atrial pressure) compared to the underlying stenosis (left ventricular pressure). Transvalvular pressure gradient confirms the diagnosis and assess the severity of mitral stenosis.
Cardiac catheterization is also used in the evaluation of ischemic heart disease (by identifying the obstructed coronary arteries). The treatment of mitral stenosis is established also according to the presence or, respectively the absence of the ischemic heart disease.
Mitral Stenosis Treatment – Generalities
The treatment depends on the severity of mitral stenosis and symptoms of the disease, usually occurring after a latent period of 10-40 years after the acute rheumatic attack. For people with no symptoms or mild symptoms, no treatment is not necessary, but is mandatory regular specialized medical checkups (echocardiography) to identify any changes that may occur during disease evolution.
Treatment options depend on:
The severity and evolution of mitral stenosis, with initiation of treatment only in case of more serious symptoms;
The severity of symptoms, along with their appearance;
The presence of some complications such as heart failure, pulmonary edema or ischemic heart disease which requires surgical treatment (mitral valve replacement);
The degree of damage of the morphology and function of the mitral valve; valvuloplasty (surgical correction of the native mitral valve) may be sufficient in patients with partially preserved function, in cases with poor morphology and function of the valve is indicated an artificial mitral valve placement;
General health condition and associated diseases and the patient’s age: corrective surgery can be performed through a less invasive method (valvotomy balloon) or an invasive method (open commissurotomy).
Mitral stenosis is a chronic condition which develops slowly. Once with stenosis worsening there occur certain compensatory changes of cardiac function (increased contractility, enlargement of the left atrium). In time, compensatory mechanisms are exceeded and heart failure occurs.
It takes 10-20 years of evolution up to the appearance of symptoms of the disease. This phase, called asymptomatic, requires no treatment, but periodic evaluation of cardiac function is required. We have to mention that during the asymptomatic period is mandatory an antibiotic treatment of all bacterial or fungal infections (dental infections, urinary, digestive, etc.) because people with valvular heart disease have an increased risk of developing infective endocarditis. Any bleeding maneuver made among these patients, must be preceded by appropriate antibiotic therapy.
Symptoms of mitral stenosis can occur or get worse if the heart is overworked by certain factors which are considered a risk, such as pregnancy, excessive physical exertion, emotional stress or surgery, some associated diseases.
Once with the appearing of the symptoms of mitral stenosis it is necessary to establish a medical treatment to prevent heart failure.
Medical treatment includes the following types of medicines:
Diuretics: are medicines that help to eliminate excess water from the body; diuretics lower the blood pressure and therefore the pressure at the level of the left atrium and pulmonary veins; diuretics are used to treat pulmonary edema;
Antibiotics: are the most commonly used (prophylactically) to prevent bacterial endocarditis (infection of the heart valves and chambers) and are administered whenever the patient has an infection (dental, urinary, digestive and so on) or will perform an invasive maneuver, which may favor the spread of the infection;
Antiarrhythmic medications: beta blockers, calcium channel blockers, digoxin, are successfully used in the treatment of atrial fibrillation (common arrhythmia in patients with mitral stenosis);
Anticoagulant medication: is still used prophylactically, it helps to fluid the blood and prevents thrombus formation at the level of the dilated left atrium.
Surgical treatment of mitral stenosis can be performed by three methods:
Balloon valvotomy: it is a less invasive method which involves inserting a balloon catheter through an artery to the heart cavities; once arrived at the level of stenotic mitral valve, the balloon inflates suddenly to try to widen the narrowed opening, the method is uncomplicated and effective in most cases and requires no surgical incision of the chest and heart;
Open Commissurotomy: is an invasive surgical procedure that requires incision of the chest and heart; valvuloplasty consists of cleaning and repairing the stenosed mitral valve (removal of calcified deposits and fibrous test);
Mitral valve replacement: is an invasive surgical procedure that requires incision of the chest and heart; after establishing extracorporeal circulation, it is incised the heart and replaced the mitral valve with an artificial mitral valve; the replacement is performed only in patients who developed complications of mitral stenosis.
Mitral valvotomy with percutaneous balloon
It is a less invasive procedure, which is indicated in patients with mitral stenosis with moderate or severe symptoms.
A special balloon catheter is inserted through the femoral artery or brachial artery up to the left atrium. The moment when the catheter reaches the mitral valve orifice the balloon is inflated in an attempt to widen the stenosis. This method is effective in most cases, widening the mitral orifice diameter sufficient to ensure normal blood flow to the rest of the body and can be repeated at a certain time.
Valvotomy with balloon is a less invasive method that provides a rapid recovery and does not require open-heart surgery.
The method can be used also in asymptomatic mitral stenosis among persons who have however these symptoms:
Moderate or severe mitral stenosis (mitral orifice diameter of less than 2 cm);
Relatively good functional mitral valve (symptoms occurred only at great effort);
Pulmonary hypertension (high pressure in the pulmonary blood flow);
Atrial fibrillation or other arrhythmias associated with mitral stenosis;
Left atrial thrombosis (the presence of blood clots in the left atrium);
Mitral stenosis complicated by mitral regurgitation (mitral valve disease), is a contraindication to balloon valvotomy.
Open heart surgery
In cases when mitral valve is hopelessly degraded, we recommend replacing it with an artificial prosthesis. This can be done only through open heart surgery, which involves stopping the heart (after extracorporeal circulation).
There are 2 types of prosthetic valves that can be used in the treatment of mitral stenosis:
Mechanical prosthesis, made of a plastic material or metal;
Biosynthetic prosthesis made of animal tissue (usually pigs).
The pros and cons of mitral valve replacement
Prosthetic heart valves are used more frequently among patients younger than 70 years. However, this valves predispose to formation of emboli (blood clots) that can cause strokes after their mobilization. For this reason, patients with mechanical valves require anticoagulation for lifetime.
Biosynthetic prosthetic valves are used among elderly patients (age bigger than 70 years) and have the advantage of not requiring permanent anticoagulation. But their disadvantage is the need of replacement within an interval of about 10 years.
Mechanical prosthesis is the most commonly used among patients with mitral stenosis even if it requires continuous anticoagulant therapy, as in recent years there have appeared new prostheses which perform an almost identical functionality like the native mitral valve. It is important to mention that anticoagulant treatment may sometimes be necessary among patients with biosynthetic valves (dilated left atrium, the presence of intra atrial thrombus, presence of the atrial fibrillation).
Mitral Stenosis Evolution
After the onset of the symptoms of mitral stenosis it is required an interval of approximately 3-10 years until developing complications or installation of the heart failure. Once with the worsening of the symptoms the conservative medicinal treatment becomes insufficient, being required mitral valve replacement surgery.
Mitral Stenosis Complications
Although the mitral stenosis is considered chronic, mild, slowly unfolding, there are some complications that can occur suddenly and can aggravate the disease.
The most common complications that can occur in people with mitral stenosis are the following:
Cardiac arrhythmias (disorders characterized by irregular, abnormal heart beats);
Heart failure (inability of the heart to provide oxygen and nutrients necessary for the functioning of other organs);
Bacterial endocarditis (infection of the heart valves.
All these complications require emergency medical treatment, since they are life threatening (acute heart failure).
The life of patients with mitral stenosis
People diagnosed with mitral stenosis should avoid excessive exercise, as it may aggravate the disease. Specialized medical control is required periodically to establish the type of exercise that can be performed by the patient. With the appearance of the signs of heart failure, exercise should be significantly reduced to prevent complications.
In some cases it must be considered even the changing of the patient job if it involves making an exaggerated physical effort.
There are recommended walks and medical gymnastics exercises. Not recommended swimming, jogging or aerobics.
Mitral stenosis requires the establishment of a proper diet to prevent the possible occurrence of some complications. Low-salt diet is required (with a low-salt content) to avoid loading volume and edema. The excess of the fluid increases the mechanical work of heart and worsens heart failure. Foods that should be avoided are: chips, peanuts, processed meat, cheese, canned food, pizza, olives, food fast and pre-cooked food.
Every time you consume new foods it is recommended you carefully read the labels. Also consult your doctor if the medication change (there are some medicinal preparations that have a high sodium content and must be avoided).
People diagnosed with mitral stenosis have an increased risk of developing infective endocarditis. Bacterial endocarditis usually occurs on previously damaged valves and rarely in patients with normal native valve. Antibiotic treatment is necessary every time a patient is diagnosed with mitral stenosis and performs an invasive maneuver.
Antibiotic therapy is mandatory before any of the following operations:
Dental bleeding interventions;
Any kind of surgical procedures;
Cesarean section (physiological birth is contraindicated among patients with mitral stenosis);
Trauma (fractures, bruises, cuts, etc.)
Effectuating investigations such as: upper digestive endoscopy, colonoscopy, cystoscopy, gastro-duodenal tube, etc. (only in certain carefully selected cases).