Aortic Stenosis – Symptoms, Diagnosis And Treatment
stenosis represents a reduction of the aortic valve opening due to pathological processes that lead to thickening, fibrosis, calcification and its merger with the formation of a barrier to the left ventricular outflow tract.
Congenital lesions predominate in younger patients (bicuspid valve, unicommissural valve), in which the process of fibrosis and calcification will amplify over time. Degenerative etiology is prevalent in old age, in which the cusps are restrained by calcium deposits.
Valvular aortic stenosis, by the obstacle that is representing in the way of left ventricular ejection, cause an increase in the cardiac afterload (cardiac labor) and in the gradient between left ventricle and aorta. The heart is reacting by concentric left ventricular hypertrophy, in the first phase of compensation, until the adaptive reserves are depleted when the left ventricle begins to dilate and will appear heart failure phenomena.
Three symptoms are suggestive for aortic stenosis:
- Angina pectoris;
- Sudden death.
In advanced stages of cardiac decompensation occurs: effort and rest dyspnea, palpitations by installation of atrial fibrillation, cerebral embolism(stroke) or systemic embolism, fatigue and risk of infective endocarditis. Some patients remain asymptomatic for a long period of time. Even in these cases there is risk of sudden death, which is why tracking and treatment of these patients is important.
Aortic stenosis degrees:
Normally the aortic orifice area in adults is 3-4 cm².
Depending on the degree of narrowing, aortic stenosis is classified in:
- Large aortic stenosis (between 2.5 cm² and 1.5 cm²);
- Moderate aortic stenosis (between 1.5 cm² and 1cm²);
- Severe aortic stenosis (less than 1 cm²).
Patients with aortic stenosis remain asymptomatic for years despite the severe obstruction. A moderate aortic stenosis (aortic orifice area between 1 to 1.5 cm²), remains without complications, but 40% of patients with hemodynamically significant stenosis develop symptoms over the next 1 or 2 years. The onset of the symptoms like angina pectoris, syncope, shortness of breath after a long period of evolution of aortic stenosis, marks the beginning of cardiac decompensation and the aortic stenosis should be treated to avoid sudden death. Most studies have shown that the sudden death have a incidence of 1% in asymptomatic patients, but in those symptomatic, the incidence of sudden death is 20% – 30%.
Life expectancy is 1 or 2 years for patients with heart failure phenomena, 2 or 3 years in those with syncope and 4 or 5 years, in patients with angina pectoris. Among patients with severe aortic stenosis, medically treated, 50% die in 2 years, half of them by sudden death.
Knowing the natural evolution of aortic stenosis, helps the physician to take the most appropriate measures in some point in the evolution of the disease.
Clinical and paraclinical diagnosis of aortic stenosis:
Diagnosis by physical examination of the patient is easily made by characteristic elements like loud and rough systolic murmur in aortic focal, with irradiation to the neck vessels, large apexian shock, pectoral thrill and pulse “parvus et tardus” (late and slow).
Clinically diagnosed patients are subjected to laboratory tests that cuts and nuanced the diagnosis of aortic stenosis: ECG, cardiothoracic radiography and cardiac echocardiography. Of these, echocardiographic study in M-mode, two-dimensional mode and Doppler mode, confirm the diagnosis, staging the aortic stenosis and asses the aortic valve lesions.
Echocardiography is useful in aortic stenosis because:
- Specifies the diagnosis of aortic stenosis and severity of injury;
- Assessing the heart size and function, left ventricular dimension in systole and diastole andventricular hypertrophy;
- Assessment of the mitral valve, tricuspid valve and pulmonary hypertension;
- Regular reassessment of asymptomatic patients with aortic stenosis;
- Tracking the hemodynamic changes in pregnant women with aortic stenosis.
Ultrasound tracking of patients with asymptomatic severe aortic stenosis shall be done at 6-12 months and in those with moderate aortic stenosis at 2 years.
Exercise testing is not indicated in patients with severe aortic stenosis, being even dangerous, and the information are insignificant.
Cardiac catheterization. Is performed in all patients proposed for surgery, which risk factors for coronary heart disease, to assess the coronary system. Also when there is a discrepancy between clinical features and echocardiographic data, cardiac catheterization, accurately measure the transvalvular flow, the gradient between the aorta and left ventricle, the aortic effective orifice area and left ventricular function.
Medical treatment. In patients known with aortic stenosis, is done the prophylaxis of infectious endocarditis in the case of dental maneuvers or gynecological surgery, by administering antibiotics during this period. Associated hypertension is also accordingly treated. Evolution in patients with severe aortic stenosis which is treated with drugs is unfavorable, with 50% mortality at two years, half of them by sudden death.
Surgical treatment. Surgery represents the treatment of sever aortic stenosis, especially if is symptomatic. The goal of surgery is to eliminate symptoms, prevent sudden death, improved ventricular function, increased life expectancy and active reintegration of patients into family and society.
Indications for surgery in aortic stenosis:
- Severe aortic stenosis in newborns;
- Severe aortic stenosis, symptomatic at any age;
- Moderate aortic stenosis associated with coronary lesions;
- Moderate aortic stenosis associated with other valve lesions that have surgical indication;
- Aortic stenosis in asymptomatic patients who have ventricular dysfunction, ventricular hypertrophy, severe hypotension or ventricular tachycardia during exercise.
Postoperative evolution. Complications:
Operative mortality in elective interventions is less than 3%, increasing in extreme ages, newborns, elderly, emergency operations, the presence of endocarditis and associated pathology.
Immediate postoperative complications are dominated by bleeding, disturbances in heart conduction, embolic stroke, low cardiac output syndrome, kidney failure and respiratory failure. In the long run the survival is 75% at 5 years and 60% at 10 years, with risk of endocarditis, complications of anticoagulant treatment, bleeding or valve clogging, cerebral or peripheral embolism. All these complications depend on the parameters of the patient before surgery (cardiac function, age), surgical technique and postoperative care.