Rheumatic heart disease
Diagnosis, treatment and prognosis of rheumatic heart disease
Rheumatic heart disease (RHD) is one of the leading causes of cardiovascular disease in developing countries. The incidence of rheumatic heart disease has decreased significantly over the past 20-30 years in developed countries.
Worldwide prevalence
In developing countries, RHD is one of the leading causes of cardiovascular disease among young patients. Approximately 25% of heart failure among patients living in endemic countries is due to RHD. Studies show that about 70 million people worldwide suffer from RHD, and 1.4 million of them die each year.
The natural course of the disease
The course of RHD includes the following pathologies:
- In acute rheumatic fever, pericarditis, myocarditis, and valvulitis (inflammation of the heart valves) occur.
- Chronic valve pathologies, may develop several years after one or more episodes of acute rheumatic fever.
Acute rheumatic fever
Acute rheumatic fever mainly causes the development of pancarditis and leads to inflammation of the pericardium, myocardium and endocardium of the heart. Valvulitis, or inflammation of the heart valves, is also common. Valvulitis is often diagnosed by auscultation (listening to the heart tones with a stethoscope). However, it should be noted that in some cases, the murmur of regurgitation (which is heard when the heart valves are insufficient, with backflow of blood) on the valves may not be audible.
EchoCG may reveal the following changes:
- Thickening of the valve cusps
- Vegetations on the valves (foci of infection)
- Mitral valve prolapse
- Regurgitation on mitral and/or aortic valve
However, it should be noted that the detection of regurgitation in the mitral or aortic valve region on EchoCG does not confirm the diagnosis of rheumatic valvulitis. Thus, physiological regurgitation (mild regurgitation) of heart valves may be observed in normal subjects. At the same time, valve regurgitation may also be seen in other febrile diseases (e.g., viral myocarditis).
Figure 1: Normal mitral valve and prolapsed
The most common valve pathology in patients with RHD is regurgitation. Along with mitral valve insufficiency, aortic valve insufficiency may be observed. However, isolated aortic regurgitation is very rare. Mitral regurgitation (MR) most commonly occurs with mitral valve prolapse. (Figure 1)
In acute rheumatic fever (ARF), mitral valve prolapse is mainly caused by damage to the anterior valve leaflet. In myxomatous heart disease, the posterior valve leaflet is usually involved.
Mitral valve prolapse in RHD is caused by enlargement of the valve ring (annulus) and lengthening of the chords. If aortic or mitral stenosis is detected in the RHD, it indicates a long-term course of the disease, scarring and calcification of the damaged valve tissue.
Left ventricular dilatation and heart failure can also be seen in patients with RHD and severe valve malformation. Various degrees of heart rhythm block, including atrioventricular dissociation, may be detected on ECG in patients with RHD. A chest X-ray may reveal cardiomegaly (increased heart size). EchoCG in patients with RHD can accurately assess valve pathology, pericardial effusion (fluid accumulation in the pericardial cavity), ventricular and atrial dilatation, and ventricular function.
Transition of rheumatic heart disease from acute to chronic
In most cases, the progressive development of valve heart disease occurs several years after one or more episodes of acute rheumatic fever (ARF). Studies have shown that approximately 50-65% of children with ARF develop valve heart disease shortly after the onset of fever. A U.S. study found that 35% of patients seen within 20 years of the first episode of acute rheumatic fever had no valve lesions, and 17% had spontaneous cure of the lesions that occurred. However, 20 years later, symptoms of valve heart disease appeared in 44% of these patients.
Figure 2: Comparison of a heart valve with mitral stenosis and a normal mitral valve
Chronic heart valve disease
In most cases of ARF, the mitral valve is involved, and the aortic valve is damaged in only 20-30% of cases. Although tricuspid valve damage occurs rarely, it is usually subclinical (i.e. asymptomatic). The degree of mitral valve damage varies depending on the age of the patient. Younger patients (up to 30 years old) have only mitral valve insufficiency, middle-aged patients (>30 years old) have mitral stenosis, and elderly patients have mixed mitral valve pathology (both insufficiency and mitral stenosis - combined mitral valve defect).
Mitral stenosis. (Figure 2)
Studies show that the overall prognosis is much better in patients older than 10 years with asymptomatic (no signs of disease) mitral stenosis or with a course with minimal symptoms. However, in symptomatic patients without surgical intervention, the clinical condition gradually worsens and the chances of survival decrease significantly. Patients with pulmonary hypertension (increased pressure in the pulmonary artery) have a lower chance of survival.
It should be noted that among all acquired heart defects, mitral valve stenosis is the most frequent cause of systemic thromboembolism. Along with mitral stenosis, the risk of thromboembolism is even higher in patients with atrial fibrillation.
Mitral regurgitation
Increased cardiac output due to chronic mitral insufficiency may not be felt for many years. Thus, decreased left ventricular resistance ("afterload") due to mitral regurgitation (systole in which part of the blood returns to the left atrium during heart contraction) delays the diagnosis of left ventricular dysfunction.
Mitral stenosis and regurgitation
Most patients with rheumatic mitral valve malformation have concomitant mitral valve malformation (mitral stenosis with regurgitation components). This is caused by the formation of adhesions (adjoining parts of cusps) between mitral valve commissures as a result of pathological process and deformation of the valve, in the form of so-called "fishmouth deformity". (Figure 3) Both stenosis and insufficiency are due to deformation and abnormal movement of the valve cusps.
Figure 3: “Fishmouth deformity” in mitral stenosis
Aortic regurgitation
Patients with chronic severe aortic regurgitation usually have a long compensatory phase. Thus, this stage is characterized by increased left ventricular volume at the end of diastole, as well as eccentric and concentric hypertrophy (wall thickening) of the left ventricle. However, despite left ventricular dysfunction (impaired function), 25% of asymptomatic patients develop signs such as angina and heart failure each year. Also, patients with symptoms of severe aortic regurgitation have an annual mortality rate (death rate) of more than 10%.
Aortic stenosis
Aortic valve stenosis usually develops over many years, and is characterized by a varied clinical course. When a patient develops symptoms caused by aortic stenosis, the mortality rate increases significantly. Without surgery (surgical replacement of the aortic valve), patients can live only 2 to 3 years if they develop angina, syncope, or heart failure.
Tricuspid valve disease
Tricuspid valve functional insufficiency is mainly associated with right-sided heart failure. This condition is caused by enlargement of the right ventricle and distension of the valve ring (the area where the valve leaflets are held together). Organic tricuspid valve insufficiency results from shortening and thickening of the valve leaves, which leads to incomplete closure of the valve leaves during systole (heart contraction).
Normal tricuspid valve area is >7 sq.cm, and a decrease in this area to <1.5 sq.cm is indicative of hemodynamically significant (circulatory disturbance that may pose a danger to the patient) stenosis. Tricuspid valve stenosis due to rheumatic disease is often accompanied by mitral valve malformation. Tricuspidal stenosis without regurgitation is rare.
TREATMENT
Slowing down of the disease process
Penicillin secondary prophylaxis is known to reduce the incidence of streptococcal infection, the number of recurrent episodes of acute rheumatic fever, the duration and frequency of hospitalizations of patients with acute rheumatic fever and RHD. According to the World Health Organization, secondary prophylaxis in patients with RHD or mild carditis (e.g., mild mitral insufficiency or recurrent carditis) should continue for at least 10 years after the last episode or until the patient reaches 25 years of age.
In patients with a more severe degree of valve damage (e.g., heart failure), as well as in patients who have undergone heart valve surgery, secondary prophylaxis should be continued throughout life.
Treatment of mitral insufficiency (regurgitation)
Patients with mild rheumatic mitral regurgitation (MR) usually remain asymptomatic for a long time and therefore require annual examination. Patients with moderate MR should be re-examined every 6-12 months. Examination of these patients should include physical examination, cardiac auscultation, and EchoCG to assess left ventricular systolic function. Detection of signs of left ventricular systolic dysfunction (PV<60% and/or left ventricular end-systolic dimension >4.5 cm) is considered appropriate to prepare patients for surgery.
Rheumatism causes fibrous thickening of mitral valve leaflets and scarring of chords (subvalve structures). This, in its turn, leads to short-term positive result after mitral valve plasty. However, in patients with rheumatic mitral insufficiency, reconstructive surgery (preservation of the patient's own valve) is considered more useful. A study in France showed that after surgical mitral valve reconstruction for rheumatic mitral insufficiency, the survival rate among patients was 10% at 10 years and 82% at 20 years. Also, reoperation after 10 years was required only in 18% of patients, and after 20 years in 45% of patients. The main reason for reoperation was progressive valve leaflet fibrosis. In patients in whom mitral valve repair is impossible, it is replaced by a mechanical or bioprosthetic valve. It should be noted that the survival rate among patients who underwent valve plasty is higher than in those in whom the mitral valve was replaced with a mechanical or bioprosthesis.
A number of studies have also shown that although the rate of reoperation is the same among patients who have undergone plastic and prosthetic valve repair, the mortality rate is lower in patients who have previously undergone surgery for valve repair. Another argument in favor of mitral valve plasty is the fact that these patients do not require continuous anticoagulant therapy (anticoagulants, antiaggregants).
Treatment of mitral stenosis (MS)
According to the recommendations of American and European societies on heart disease, pulmonary artery pressure measurement should be performed: every 3-5 years in patients with mild mitral stenosis (MS); every 1-2 years in patients with moderate mitral stenosis; annually in patients with severe asymptomatic mitral stenosis. EchoCG is used for this purpose. EchoCG should be performed more frequently in symptomatic patients.
Because mitral stenosis is a mechanical pathology, patients with moderate to severe stenosis require evaluation by a cardiovascular surgeon for valvuloplasty (balloon or open) or surgery as soon as symptoms appear. Patients with moderate to severe mitral stenosis and pulmonary edema should be medically stabilized and referred to valve repair centers for emergency surgery and valvuloplasty.
Studies show that pulmonary hypertension significantly increases the risk for surgery. Thus, when pulmonary hypertension (pulmonary artery pressure > 50 mm Hg) and mitral stenosis are combined in asymptomatic patients, early surgery is more appropriate.
End-stage uncorrected severe mitral stenosis can be aggravated by pulmonary hypertension and right-sided heart failure, edema and ascites (fluid accumulation in abdominal cavity). These patients also have tricuspid regurgitation, which develops mainly due to dilatation (expansion) of the right ventricle.
Atrial fibrillation (AF)
Patients with mitral stenosis have a significantly higher risk of atrial fibrillation. Although episodes are paroxysmal (episodic) at the beginning of the disease, over time they become persistent (prolonged). As atrial fibrillation persists for many years, ventricular filling is impaired due to an accumulation of blood in the atria, due to a disturbance in their contraction. Studies have shown that cardiac output is reduced by about 30% in patients with atrial fibrillation. There is also an increase in ventricular contraction rate during AF, which leads to a shorter ventricular filling time during diastole. Such changes can lead to increased pressure in the left atrium and, therefore, require urgent treatment. At the same time, these patients have a significantly increased risk of thromboembolic complications.
Prevention of thromboembolism
Patients with mitral stenosis have a higher risk of thromboembolism and embolic events. This risk is even higher in patients with paroxysmal or persistent atrial fibrillation, intra-left atrial thrombus or previous embolism.
Treatment of concomitant mitral valve malformation
Herewith, natural course and prognosis of the disease in patients with both mitral stenosis and insufficiency are worse than those with isolated regurgitation. Only 2/3 of patients with untreated mitral valve defect survive within 5 years, and only 1/3 - within 10 years. Patients with symptomatic failure as well as moderate mitral regurgitation and moderate mitral stenosis require valve replacement.
Aortic regurgitation
In patients with aortic regurgitation, the development of symptoms and systolic dysfunction is gradual. Therefore, periodic monitoring of patients with aortic insufficiency is recommended. Patients with mild to moderate aortic insufficiency have a high survival rate, and usually do not require surgical intervention. When symptoms are severe and left ventricular function is impaired (LV EF (left ventricular ejection fraction) <50%) or left ventricular size is increased (left ventricular end-diastolic dimension >75 mm or left ventricular end-systolic dimension >55 mm), patients are indicated for surgery.
Treatment of aortic stenosis
Treatment of asymptomatic aortic stenosis consists of regular periodic monitoring, treatment of concomitant cardiovascular disease, and restriction of physical activity. Currently, there is no effective drug therapy to prevent progressive valve leaflet damage in aortic stenosis. Awareness of the symptoms of the disease is of particular importance. Thus, if there is shortness of breath, decreased physical performance, chest pain, dizziness, and fainting, an experienced surgeon should be seen immediately. Periodic EchoCG examination is recommended to monitor the progression of valve stenosis in patients.
Combined aortic valve disease
At the same time, clinical symptomatology in patients with aortic insufficiency and stenosis depends mainly on which of the above is more severe. For example, patients with more severe insufficiency have a clinicopathology suitable for regurgitation. The clinic is also confused when two valve pathologies of the same severity are combined. Treatment of combined aortic valve pathology usually consists of physical examination every 6-12 months, EchoCG if symptoms or left ventricular dysfunction are detected. If symptoms are observed or left ventricular function worsens, surgery for aortic valve replacement is required.
Treatment of tricuspid valve malformation
Despite the lack of information in the literature sources, it should be noted that surgery for percutaneous balloon valvulotomy is possible in patients with severe tricuspidal stenosis. In patients who cannot undergo balloon valvulotomy, severe tricuspid stenosis is corrected by surgery.
Tricuspidal insufficiency is often diagnosed in patients with rheumatic heart disease. The course of tricuspid regurgitation can worsen, after mitral valve surgery. For patients with both mitral and moderate to severe tricuspid valve insufficiency, annuloplasty (placement of a special 3D ring at the base of the valve) of the tricuspid valve is recommended for surgical correction of the mitral valve.
Pregnancy
Women with heart defects are advised to consult a physician before pregnancy and discuss all potential risks and possible complications. Women with valvular heart defects should be monitored by a cardiologist during pregnancy.
General preventive measures
As mentioned above, rheumatic fever in patients with rheumatic heart disease should be prevented. It is especially important to vaccinate these patients against influenza every year, to observe strict dental and oral hygiene, and to be examined by a dentist once a year.
In patients with prosthetic heart valves, as well as in patients with previous infective endocarditis, antibiotic prophylaxis for infective endocarditis should be performed before any invasive procedure, including invasive dental procedures.