Aortic stenosis, what is it and what are the consequences?

By Cristiano Antonino On Jun 22, 2023

Also called aortic valvular stenosis, aortic stenosis occurs when the aortic valve (one of the four heart valves) becomes obstructed or narrowed

Similar in shape to a half moon, the aortic valve is located between the aorta and the left ventricle of the heart

Its particular shape and position prevent oxygen-rich blood from ‘flowing back’: it is therefore a kind of ‘faucet’, essential for forcing the blood to proceed in one direction only, without ever reversing its course.

The three membranes that compose it (cusps, in medical language) are mainly made of collagen, and its position on a muscular ring connected to the heart underlines its importance: it is through the aorta that oxygen-rich blood reaches all organs and tissues, and the task of the aortic valve is precisely that of opening when the left ventricle pumps blood into the aorta, contracting.

In the patient suffering from aortic stenosis, the flow of blood from the ventricle to the aorta is blocked or slowed due to a narrowing or obstruction of the valve.

Most common in older people, the condition affects 2% of people over 65, 3% of people over 75 and 4% of people over 85, regardless of gender.

Aortic stenosis, what is it?

A disease of the aortic valve, and thus of the heart, aortic stenosis is the most common valvular disease.

If not diagnosed and treated in a timely manner, in its most severe forms it causes the death of the patient in 50-70% of cases within three years of its onset.

Sufferers suffer a narrowing of the aortic valve and, therefore, the valve that allows blood to pass from the left ventricle to the aorta without returning.

This condition forces the ventricle to pump more vigorously to overcome the obstruction, causing a thickening of the heart wall: the heart can no longer function properly, it needs more blood, and when this is not enough, the person may feel a sense of chest constriction and faintness.

Aortic stenosis: the causes

The most common cause of aortic stenosis is senile aortic calcification, which is responsible for more than half of all cases.

Most common in the over-65s, as it is linked to the physiological ageing process of the body, it consists of the formation of calcium deposits on the membranes of the aortic valve.

Unlike fatty deposits (atherosclerotic plaques) in the coronary arteries, which are typical of atherosclerosis, calcium deposits are not caused by unhealthy eating habits or lack of physical activity.

Another frequent cause of aortic stenosis is the bicuspid aortic valve, responsible for most diagnoses in patients under 65 and present in 2% of the population.

A congenital anomaly, it is due to a defect in the development of the valve which – instead of three membranes – develops only two.

While performing its function normally, the valve structured in this way puts the heart in a position to pump more to pass through a narrower cavity.

And the valve narrows further because, over time, it too is subject to the formation of calcium deposits.

By contrast, the most common cause of aortic stenosis in developing countries is rheumatic fever, a complication of group A beta-hemolytic streptococcus infections: the aortic valve cusps become inflamed, thickened and fused, and the patient often also suffers from aortic insufficiency (blood flows back from the aorta into the left ventricle).

There are risk factors that increase the risk of suffering from aortic stenosis

congenital abnormality of the aortic valve
calcium deposits on the valve due to ageing
infections contracted during childhood, which can affect the health of the heart
diabetes mellitus
hypertension
hypercholesterolaemia
chronic renal insufficiency
radiotherapy sessions to the chest

Aortic stenosis: symptoms

People who suffer from aortic stenosis due to a congenital defect generally do not experience specific symptoms, and do not know they suffer from it, until adulthood.

When symptoms do appear, the patient experiences chest pain, a sign that the heart is suffering because it is not receiving enough oxygenated blood.

Aortic stenosis, in its most severe stages, leads to hypertrophy of the left ventricle, which therefore needs an increased supply of oxygenated blood: the vessels that serve the myocardium (coronary arteries) are no longer sufficient to fulfil this need, however, and the ventricle does not get enough oxygen.

This results in what is known as angina pectoris, a reversible chest pain that may be associated with a feeling of heaviness and tingling in the upper limbs and chest.

Other typical symptoms of aortic stenosis are dyspnoea (shortness of breath), typically during exertion but also at rest when the condition is very severe, and syncope.

The left ventricle does not pump enough blood and it is the brain that is affected: the person rapidly and temporarily loses consciousness, only to recover spontaneously and without damage (generally benign, syncope becomes a serious alarm bell when it has cardiac origins).

The patient may also experience arrhythmia, palpitations and fatigue.

Aortic stenosis has different clinical manifestations in adults and children: the former often emit a heart murmur that can be detected with a stethoscope, the latter may experience symptoms such as frequent fatigue, difficulty gaining weight and difficulty breathing normally.

The diagnosis

The cardiologist often arrives at the diagnosis of aortic stenosis after detecting a heart murmur during a routine check-up.

However, if you frequently suffer from chest pain, episodes of syncope and dyspnoea, an early consultation is essential.

The doctor will first perform an objective test with a stethoscope to check for a possible heart murmur between the 2nd and 3rd intercostal space.

To measure the health of the left ventricle and the severity of aortic stenosis, an electrocardiogram is required, while echocardiography gives an all-round view of the health of the heart (not only ventricles and valves, but also atria and vessels) and calculates the speed of blood flow when combined with the colour-Doppler technique.

The cardiologist may also prescribe a chest X-ray to rule out massive calcifications, an exercise test and – in certain circumstances – a cardiac catheterisation.

An invasive diagnostic test, the latter consists of inserting catheters into the vasculature and leading them to the heart: here, they can accurately measure the size of the valve openings and the pressure inside the ventricles.

Treatment

There are several treatments for aortic stenosis.

If an infant suffers from a congenital malformation, a specific drug is usually administered into a vein to reopen the ductus arteriosus (the vessel that connects the aorta to the pulmonary artery): by staying open, rather than closing immediately after birth, the ductus helps blood to reach organs and tissues when the artery alone is not sufficient.

However, this is a temporary solution, pending definitive surgery, to be scheduled as soon as the infant’s condition permits.

If aortic stenosis is mild and asymptomatic, it is only monitored with periodic medical check-ups; in contrast, severe stenosis generally requires surgery.

There are no drugs that resolve it, only drugs that control its symptoms:

diuretics and ACE inhibitors reduce ventricular pressure and are especially useful when heart failure is also present;
beta-blockers and calcium channel blockers control angina pectoris;
antibiotics are prescribed when the patient has endocarditis, i.e. infection of the inner lining of the heart.

Surgery is aimed at repairing or replacing the aortic valve

Repair of the aortic valve consists of its remodelling, and can be performed invasively (via thoracotomy) or minimally invasively (transcatheter). However, it is not always feasible and its applicability depends on the patient’s general condition.

Aortic valve replacement consists of removing the defective valve and replacing it with a new artificial or biological valve (the former has several contraindications but lasts a long time, the latter is safer but less durable). Here too, it is possible to opt for an invasive or minimally invasive technique, depending on the clinical history of each individual case.

Balloon catheter valvuloplasty allows the aortic valve to be dilated without replacement via a catheter that is passed through the femoral artery. This is a non-definitive solution, generally adopted for younger patients in order to avoid a more invasive approach.

Apart from the chosen therapy, aortic stenosis sufferers need to make a change in their lifestyle by quitting smoking, adopting a healthy diet and exercising regularly to keep their weight under control.

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The prognosis of stenosis depends on the severity and thus on how early it is diagnosed. If the diagnosis is late, the most severe forms have a 70% mortality rate within three years.

Surgery, on the other hand, increases the chances of survival to that of the general population.

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