In aortic stenosis, the junction between the heart and aorta is narrowed due to heart valve damage. The heart must exert more force to pump blood through the narrowing and will be damaged in the long term without therapy.
What is aortic stenosis?
Aortic stenosis is a heart valve defect that causes the outflow tract of the left ventricle to narrow. As a result of the narrowing (stenosis), there is a pressure load on the left heart, which in many cases leads to left heart failure. Symptomatic manifestations of aortic stenosis include dizziness, shortness of breath and syncope (fainting) on exertion, cardiac arrhythmias and angina pectoris attacks. Depending on the location of the stenosis, three forms of the disease are differentiated. The so-called valvular stenosis is characterized by a narrowing of the aortic valve (typical aortic stenosis). In supravalvular stenosis, the narrowing is located above the aortic valve. So-called subvalvular stenosis is caused by membranous thickening of the outflow tract or hypertrophic obstructive cardiomyopathy (thickening of the muscles of the left ventricle).
Causes
A general distinction is made between degenerative (acquired) and congenital (congenital) aortic stenoses. Congenital stenoses are mostly attributable to morphologic abnormalities (malformations) of the heart valve. For example, the affected valve may consist of only two valve leaflets instead of three (bicuspid aortic valve), allowing only a small opening. Affected individuals between the ages of 40 and 60 usually suffer from acquired valve stenosis. This may manifest as a result of rheumatic fever or bacterial endocarditis (inflammation of the inner lining of the heart). In affected individuals over 60 years of age, the majority of cases are due to aortic sclerosis (calcifying valve stenosis or senile form). Additional risk factors for acquired aortic stenosis include smoking, renal insufficiency (decreased renal function), hypercalcemia (increased calcium concentration in the blood), hypertension, and diabetes mellitus.
Symptoms, complaints, and signs
In the worst case, aortic stenosis can lead to the death of the affected person. However, this case usually occurs only when aortic stenosis is not treated. Since there is no self-healing, the affected persons are dependent on treatment in any case. The patients suffer primarily from a strong feeling of dizziness and furthermore also from shortness of breath. In severe cases, this can lead to a loss of consciousness, during which the affected person can also injure himself. Loss of consciousness can also occur without physical exertion. Due to aortic stenosis, many affected individuals also suffer from disturbances of the heart rhythm and thus heart pain. Without treatment, this eventually leads to permanent damage to the heart and likewise sudden cardiac death. The surrounding vessels are also damaged by aortic stenosis, so that further disease can develop without treatment. Patients often appear fatigued and tired, and this fatigue cannot be counteracted by sleep. It also significantly reduces the patient’s ability to cope with stress. In many cases, the limitations in daily life also lead to psychological discomfort, making aortic stenosis patients dependent on psychological treatment.
Diagnosis and progression
On auscultation, a murmur can be heard (systolic heart murmur) during the contraction phase due to altered hemodynamics (flow dynamics of blood). In terms of differential diagnosis, aortic stenosis must be differentiated from mitral valve regurgitation, pulmonary stenosis, and ventricular septal defects by further examination. Echocardiography may reveal left ventricular hypertrophy and a fibrotically thickened or calcified valve with reduced mobility. In addition, a chest x-ray shows a dilated aorta (aortic dilation and elongation). Color Doppler echocardiography and cardiac catheterization can determine the valve opening area and pressure gradient. Initially, aortic stenosis is usually asymptomatic. The first symptom is usually dyspnea on exertion (dyspnea on exertion) with syncope.Since the upstream sections of the heart have to exert more force to pump the blood through the constriction into the large systemic circulation, the heart muscle thickens as it progresses and requires more oxygen. However, the coronary vessels supplying it are located downstream of the constriction. This leads to reduced blood flow and further damage to the heart muscle (left heart failure). Approximately one fifth of those affected die as a result of sudden cardiac death due to ventricular fibrillation or AV blockages (atrioventricular conduction disorder). In surgically treated sufferers, the 10-year survival rate is more than 65 percent. If left untreated, the prognosis for aortic stenosis is poor.
Complications
Complications that can arise as a result of untreated aortic stenosis are ultimately caused by the impeded flow of blood through the aortic valve. The congenital or later acquired reduced passage cross-section in the area of the aortic valve causes a reduced supply of blood to the entire body, including the brain. This is particularly noticeable after physical exertion. Shortness of breath, exhaustion and even brief fainting spells (syncope) can be the result. On the other hand, the heart tries to compensate for the reduced supply of arterial blood to the body by increasing the pumping capacity of the left ventricle. As a result, the heart muscle of the left ventricle thickens and requires more oxygen. As a rule, however, this does not work because the supplying coronary arteries branch off only behind the stenosis. Typically, in addition to dizziness, shortness of breath and brief fainting attacks, other complications such as cardiac arrhythmias and coronary heart disease develop in untreated aortic stenosis as a result of the reduced supply. The most common cardiac arrhythmia in this context is the so-called atrial fibrillation. In uncoordinated atrial contractions at high frequency, this is not immediately life-threatening, but it leads to significant performance losses and can be very unpleasant. The complications described above can be largely avoided by treatment of aortic stenosis. Apart from the risk of surgery and the possible requirement to take coagulation inhibitors (blood thinners) for life, no other complications are to be expected.
When should you see a doctor?
If cardiac arrhythmias, dizziness, or swelling in the limbs occur, the primary care physician or a cardiologist must be consulted immediately. If aortic stenosis is specifically suspected, the physician can perform an echocardiogram and rule out the condition or establish it beyond a doubt. Ideally, the disease is diagnosed at an early stage, i.e. when the first symptoms appear, such as increasing shortness of breath, tightness and chest tightness. Anyone who notices these symptoms in themselves should speak directly to their family doctor. In the early stages, aortic stenosis can usually be repaired before serious complications develop. A visit to the doctor is necessary at the latest when swelling of the ankles and lower legs, severe shortness of breath and heart palpitations occur. Although complications have often already developed by then, serious conditions such as blood clots and heart failure can still be avoided. In general, aortic stenosis should be diagnosed and treated as early as possible. Even after treatment, regular consultations should be held with the cardiologist. This allows abnormalities to be clarified promptly and serious consequences to be avoided.
Treatment and therapy
The treatment strategy for aortic stenosis depends on the severity of the disease. In mild and asymptomatic stenoses, conservative drug therapy with diuretics and digitalis (cardiac glycosides) may initially be sufficient. Affected patients should generally avoid heavy physical exertion. Endocarditis prophylaxis is indicated to reduce the risk of bacterial infection of the damaged valves. This means that patients should seek medical advice as soon as possible at the first signs of an infectious disease (including fever) so that antibiotic therapy can be initiated at an early stage if necessary. In addition, antibiotic therapy should be administered prior to surgical procedures (including dental operations) to prevent an infection. In the majority of patients, surgical intervention is unavoidable in the further course of the disease to prevent left heart failure.Especially in cases of acquired stenosis, valve replacement surgery is usually performed. Valve replacements can be mechanical prostheses made of plastic or metal, biological prostheses (usually prepared porcine valves) or human valve grafts. If artificial valves are implanted, lifelong anticoagulation (anticoagulant medication) is required. In addition, balloon dilatation of the aortic valve via cardiac catheterization may be indicated in cases of congenital stenosis. In this procedure, the damaged valve is expanded and at the same time fused valves are blown open. In children with congenital aortic stenosis, the damaged valves are increasingly removed and replaced by the patient’s own pulmonary valves. These, unlike artificial valves, grow at a normal rate with the child’s organism and allow for normal stress and athletic activities following surgery. The transplanted pulmonary valves are replaced by foreign human valves (homograft). In all cases, regular follow-up examinations are required.
Outlook and prognosis
People who suffer from aortic stenosis often have no symptoms for years. If symptoms then occur, secondary damage to the heart has often already developed. In most cases, patients also suffer from various concomitant diseases, such as anemia, hypertension, or COPD, which mask the heart’s symptoms. If aortic stenosis is not treated, this can lead to serious consequences, as blood clots can then form at the calcified aortic valve due to blood flow and reach the brain. If they block a vessel there, the blood supply is cut off and the patient suffers a stroke. Untreated aortic stenosis can also lead to cardiac arrhythmias, ventricular fibrillation, and even death. However, with surgical treatment, the prognosis for aortic stenosis is very good. However, the prognosis varies from patient to patient, as it depends on the general condition or severity of the disease as well as any concomitant diseases. Replacement of the aortic valve has significantly improved the prognosis, so that elderly patients with aortic stenosis in particular now live to the same age as persons who do not have aortic stenosis.
Prevention
The best possible prophylaxis for degenerative stenosis is to reduce risk factors. On the one hand, nicotine consumption should be avoided, and on the other hand, diseases such as rheumatic fever, diabetes mellitus, endocarditis, renal insufficiency, and hypertension should be treated adequately and early. Congenital aortic stenosis, on the other hand, cannot be prevented.
Follow-up
Severe forms of aortic stenosis require surgery, which entails regular follow-up examinations. An important contact person is the primary care physician. He or she will arrange for blood tests and electrocardiograms. Sometimes a cardiologist is also consulted as part of the follow-up. Immediately after the operation, examinations are performed at short intervals. After several years without symptoms, an annual follow-up examination is then sufficient. Mild forms of aortic stenosis, on the other hand, do not require any special therapy. Patients should only avoid physical stress. Immunity to heart problems does not build up after treated aortic stenosis. This forces sufferers to exercise little caution in everyday life. The patient himself plays an important role. He must notice the warning signs of his body and consult a doctor if necessary. Fever, infections and bleeding tendencies in particular can affect the heart. Endocarditis is considered a risk after heart surgery. If left untreated, it can lead to death. In everyday life, one should avoid stress and, if necessary, cut back on work. Cigarette consumption is considered extremely harmful to the heart. Nicotine should therefore be avoided completely. A physician will provide information about everyday consequences at the time of initial diagnosis.
What you can do yourself
A diagnosed aortic stenosis, synonymous with aortic valve stenosis, is assigned to one of three severity levels: mild, moderate or severe. While general symptoms such as shortness of breath on exertion, fainting spells, or chest pain cannot be overlooked in the moderate and high-grade severities, no subjective symptoms are usually apparent in mild aortic valve stenosis. Despite the valve defect, sports activities are recommended to strengthen and stabilize the cardiovascular system.In the case of mild aortic stenosis, there are no restrictions with regard to sports, provided that no other complaints occur during exercise. In the case of moderate aortic valve stenosis, endurance sports should be practiced without uncontrollable peak loads. Particularly suitable are hiking, Nordic walking, cycling, swimming and golfing on as level a course as possible. Most ball sports, where peak loads are difficult to control, are not well suited. Stressing the cardiovascular system and exercising as a self-help measure leads to an improved general condition. However, it is very likely that the activities will probably have no effect on the further course of the disease. If high-grade valve stenosis is present, exercise is almost impossible because the performance limitations are too severe and any performance challenges may lead to acute problems. In severe cases of aortic stenosis, neither self-help measures nor drug treatment are effective, so appropriate surgical or corrective interventions should be considered.
