Aortic stenosis is common, particularly in the setting of advancing age. However, it is an under-diagnosed entity. Early recognition and optimal management are important in order to influence the outcome of this progressive and potentially lethal disease. The following review comprehensively discusses aortic stenosis, its pathophysiology, diagnosis, natural history, and treatment.
Prevalence and Age Distribution
Aortic stenosis is the most common valvular lesion in Europe and North America. In its calcific form, the disease affects 2-7% of individuals older than 65 years. Approximately 80% of adult patients with symptomatic aortic stenosis are males. As the population is aging, so is the prevalence of aortic stenosis. By the year 2020, it had been projected to have approximately 3.5 million with aortic sclerosis and 150,000 cases of severe forms of aortic stenosis.
Pathophysiology
The most common cause of aortic stenosis in adults is the calcification of a normally trileaflet aortic valve, often due to age-related wear and tear on the aortic valve, called degenerative aortic valve disease. It is a degenerative process related to lipid accumulation, inflammation, and calcification, with features similar to coronary artery disease. Abnormal architecture of the bicuspid or even unicuspid aortic valve will result in hemodynamic stress on the leaflets, which will thicken, calcify, get stiffer, and finally lead to a narrow aortic orifice. Medically, rheumatic inflammation in the valve leaflets may lead to stenosis of the aortic valve.
Hemodynamic Severity
AHA and ACC grade aortic stenosis as mild, moderate, or severe, depending on valve area, mean gradient, and aortic jet velocity. Similar are European Society of Cardiology guidelines. Aortic sclerosis is denoted by thickening and calcification of the valve without obstruction; this might be considered separate from aortic stenosis.
Investigation
Clinical Diagnosis
A proper patient history and physical examination are self-sufficient for the diagnosis of aortic stenosis. The symptoms, which may include dyspnea on exertion, angina, dizziness or syncope, are guide post signals towards the diagnosis. The classic systolic murmur is the hallmark, with timing correlating well with the severity of stenosis. Absence of the second aortic sound is specific to Severe Aortic Stenosis only.
Radiological Diagnosis
The most accurate diagnostic tool to diagnose aortic stenosis is echocardiography. It can confirm the presence and severity, evaluate valve calcification, assess the function of the left ventricle, and give prognostic information. To evaluate the severity in the setting of AS, Doppler echocardiography is used preferably. Severe stenosis will result in a valve area of less than 1.0 cm².
The left ventricle hypertrophies to overcome the gradient across the aortic stenosis; this amount of hypertrophy increases myocardial oxygen consumption for a given left ventricular workload. Myocardial ischemia from increased left ventricular wall stress and workload demands can cause angina in the patient with severe aortic stenosis. Both left ventricular diastolic and systolic dysfunction can result in congestive heart failure. Asymptomatic patients survive an average of four years. The patient who becomes symptomatic has an average survival after symptom onset of two to three years. The development of angina or syncope or the insidious onset of symptoms of dyspnea during ordinary activities indicates the need for aortic valve replacement.
Medical Treatment
There is no effective drug treatment for advanced aortic stenosis, although certain medications may provide symptomatic relief. Digitalis or diuretics may help in the presence of pulmonary congestion. Angiotensin-converting enzyme inhibitors may have some short-term benefits. Atrial fibrillation requires urgent cardioversion and prophylaxis against endocarditis is advisable in all patients.
Surgical Treatment
Definitive management for severe symptomatic aortic stenosis is replacement of the aortic valve. Balloon valvuloplasty is not one of the recommended methods for adults but can be used as a bridge to surgery. Most of the patients who are over 40-45 years, when being subjected to the implantation of a valve, must get the exclusion of coexistent coronary artery disease through a coronary angiography. TAVR is an emerging option. However, further studies are needed.
Age alone is not a contraindication for AVR. Surgical therapy offers improved survival and symptomatic advantages in older patients over conservative treatment, and the outcomes are, in fact, no different than in age-matched normal individuals. A Web-based version of the European System for Cardiac Risk Evaluation (EuroSCORE) risk model can be accessed, and the site is at www.euroscore.org and will factor in special risk considerations when calculating operative risks.
Progression Prediction
More rapid progress of aortic stenosis is implied in patients with degenerative calcific disease associated with coronary heart disease. Natriuretic peptides predict symptom-free survival. Poor prognosis clinical predictors include advanced age and atherosclerotic risk factors. Echocardiographic predictors are calcification of the valve, peak aortic jet velocity, and left ventricular ejection fraction.
Integration of Key Considerations and Keywords
Mitral Valve Derangement Evaluated
That is, aortic stenosis is a valvular disease accompanied by many other valvular diseases, mostly mitral valve disease. Due to the above maximization of complexity of clinical pictures and thus an impact on the options of management in patients with aortic stenosis, the existence of mitral valve disease should be evaluated. One of the triggers of cardiac symptom is left ventricle mitral valve thickening; hence, it must be very much evaluated.
Replace Mitral Valve Disorder
Cases with severe involvement of both the aortic and mitral valves can necessitate a combined surgical intervention. Mitral valve disorder replacement with aortic valve replacement, however needs to be done after a very healthy evaluation of the patient's condition and cardiac function as a whole.
Common Valve Diseases: Aortic Stenosis
Aortic stenosis is a very common valve disease, particularly in the aged population. In that regard, it emphasizes the fact that there is more need to create awareness of the same and increase early diagnosis before complications emerge. Routine screening with a careful examination may result in the early detection of moderate or severe valve diseases in at-risk populations.
The evaluation of valve disease and its severity is very critical for management decisions made. Intervention at a time when valve diseases are in moderate to severe forms may prevent progression and poor outcomes. Therefore, proper management of these conditions mandates an awareness of hemodynamic severity and proper use of diagnostic tools.
Degenerative Valve Disease: Mild to Severe
Aortic stenosis is a spectrum of degenerative valve diseases ranging from mild calcified thickening to severe obstruction. Identification of early features of mild degenerative valve disease may suggest a need for monitoring and proactive intervention that could delay disease from deteriorating to its advanced states.
Minimally invasive techniques in the field of catheter heart valve repair develop new hopes for patients who are suffering from aortic stenosis. The treatments, as transcatheter aortic valve replacement does, give possibilities to patients at high risk using traditional surgical methods.
Repair or Replace Heart Valve Condition
However, treatment decisions for heart valve repair or replacement would be based on the degree of stenosis, patient age, presence or absence of other diseases, and general health. It is a multidisciplinary approach from the cardiologist to the cardiac surgeon and other relevant specialties for optimal treatment planning.
Diagnose heart valve damage
Effective management lies in the accurate diagnosis of the damage to the heart valves.
Though it is not so with aortic regurgitation, echocardiography still remains the gold standard for the diagnosis of aortic stenosis. This technique is also used for making assessment regarding the degree of damage to the aortic valve. Regular follow-ups with repeated imaging studies help in assessing the progression of the disease and deciding treatment modalities.
Widen Aorta Isolated
It is sometimes associated with other aortic stenoses, like aortic dilatation or aneurysm. In some clinical scenarios, the need to enlarge the aorta might be indicated, independent of the valve replacement procedure. This is that which a good preoperative evaluation identifies, and preconceives global surgical interventions.
Early diagnosis of aortic stenosis through physical examination and echocardiography is highly important. Surgery should be planned for elective cases and at the very onset of symptoms. Asymptomatic patients should be taken care of through careful clinical observation, a meticulous study of exercise tests, and close follow-up. Even advanced age, considered itself a risk factor, does not contraindicate aortic valve replacement because significant improvements are related to the prognosis and quality of life.
