Aortic insufficiency

The aortic insufficiency involves an alteration of the aortic valve separates the left ventricle of aorta.

In this case, the valve does not close completely during the relaxation phase of the ventricle (this is the moment when it receives blood from the atrium) and there is a reflux from the aorta.

This alteration means that the ventricle during diastole receives more blood than usual (that of the atrium and that which refluxes from the aorta), which in the long run ends up producing alterations in the functioning of the heart and its failure as a pump.

There is an acute form of this alteration, not very frequent and very serious, and a more common chronic form in which the ventricle develops adaptation mechanisms to reduce the impact of the alterations that occur.

It is more frequent in men especially (approximately 75% of cases), however, if it is associated with mitral valve disease, it occurs more in women.

Causes of aortic regurgitation

There are multiple causes of this alteration. The most common is rheumatic disease as a consequence of chronic valve involvement secondary to an episode of rheumatic fever. In this alteration, the valve is affected as a consequence of pharyngeal infection by group A streptococci, although the exact mechanism that determines this alteration at a distance is not yet known (it is believed to be mediated by immune mechanisms).

Rheumatic insufficiency is almost always associated with some degree of stenosis as it is characterized by thickening, deformity, and shortening of the leaflets, which prevents proper opening during systole and complete closure in diastole.

The congenital alteration of the bicuspid type is also associated with a certain degree of insufficiency, as well as VSD with aortic valve prolapse.

The endocarditis bacterial and traumatic rupture of the valve are the two major causes of acute aortic regurgitation. Endocarditis appears on valves previously injured by rheumatic disease, valves with congenital alterations or in exceptional cases on healthy valves. Traumatic rupture is the most serious injury and the most common of all blunt trauma to the heart.

In addition, aortic valve regurgitation can be due to diseases that cause a dilation of the aortic outlet, with which the leaflets separate without suffering any problem. This separation prevents the leaflets from joining completely, so the closure is not complete. The most common causes of this process are syphilis with aortic involvement characterized by cellular infiltration and scarring of the artery wall, ankylosing spondylitis that causes similar damage, Marfan syndrome, osteogenesis imperfecta, as well as hypertension severe arterial enlargement of the aortic annulus and dissection of the ascending aorta.

Valve insufficiency is characterized by an ineffective cessation of the aortic valve, so there is a percentage of blood that refluxes to the ventricle, which increases the amount of blood it receives (that coming from the atrium is added to that from the aorta). This causes a compensation mechanism that is the dilation of the ventricle so that it can receive more blood and also can maintain adequate flow to the aorta.

As the degree of insufficiency increases, the amount regurgitated is greater, reaching a point where the cavity has become so great that the pressure that causes its content is very high and the ventricle is not capable of developing sufficient force to drive all this content. This compensation mechanism causes the size of the heart to greatly increase, so that its oxygen needs also increase even above what the coronary arteries are capable of transporting, which can lead to angina pectoris.

As the function of the ventricle deteriorates, there is an increase in pressure in the cavities behind it (left atrium, pulmonary veins, pulmonary arteries, right chambers of the heart), in addition to decreasing the volume of blood that the rest of the organism is boosted.

Acute aortic valve regurgitation causes blood to flow back into the ventricle without it having had time to dilate, so the volume of blood delivered to the rest of the body decreases sharply and intraventricular pressure increases considerably, causing a significant increase in blood pressure. pulmonary capillary pressure causing acute lung edema. It must be fixed quickly or it leads to death.

What symptoms appear?

Severe aortic valve regurgitation (AI) generally remains asymptomatic for approximately 15 years, but once the first symptoms appear, the evolution will be rapid.

The first symptom that appears is an annoying perception of the heartbeat, especially in the decubitus position, and with exercise, tachycardia or extrasystoles develop that cause palpitations and pulsations in the head. These symptoms may be present for many years until exertional dyspnea (shortness of breath) appears, followed by orthopnea (shortness of breath except in an upright position) and paroxysmal nocturnal dyspnea.

As the disorder progresses and the heart becomes increasingly insufficient, dyspnea (shortness of breath) appears with lower levels of exercise until rest.

To this is added the symptoms of right heart failure such as congestive and painful liver venous congestion, ascites and edema in the declining areas of the body.

Chest pain due to angina pectoris is also a frequent symptom, and can appear both at rest and during exercise. The pain is usually of long duration accompanied by intense sweating and it yields poorly to sublingual nitroglycerin. Normally this chest pain appears in patients with normal coronary arteries.

Acute aortic valve regurgitation is characterized by symptoms secondary to a sudden rise in pressure in the left ventricle, which causes acute pulmonary edema and cardiogenic shock.

Diagnosis of aortic regurgitation

For the diagnosis of this as well as the rest of the valvular heart diseases, a series of different techniques are used, all very useful and that provide great information:

• Auscultation: The characteristic murmur of aortic valve regurgitation is diastolic, high-frequency, and hissing, with a decreasing tone that is best heard in the left third intercostal space. The duration and intensity of the murmur are directly related to the severity of the insufficiency. Other findings on auscultation are the existence of a third tone and sometimes a fourth tone. In addition, very precise auscultations reveal two other murmurs, a systolic ejection murmur that is heard at the base of the heart radiating to the neck and a soft diastolic that is due to the shock of the regurgitated flow from the aorta with the mitral, and that is also heard at the base of the heart.
• Electrocardiogram (EKG): Signs of hypertrophy (enlargement) of the left ventricle appear, as well as its overload. Sometimes the axis shifts to the left, which translates diffuse alteration of the ventricle, being a sign of poor prognosis.
• Chest X-ray: The dilation of the left ventricle is reflected in the X-ray with a displacement of the tip downwards and to the left in the frontal view, displacing the cardiac silhouette until it extends below the left diaphragm. If aortic valve regurgitation is due to dilatation of the aorta, this is also seen as it fills the space behind the sternum in the lateral view.
• Echocardiogram : Echocardiography shows us the degree of dilation of the ventricle, the degree of insufficiency that exists and the cause of it. It also allows us to determine the existing ventricular function and measure its deterioration. It is the most useful non-invasive method for the diagnosis and quantification of any valvular disease.
• Catheterization and cardiac angiography: This test is done when a decision needs to be made about surgical treatment. It allows us to measure with total precision the magnitude of the insufficiency and the state of ventricular function, in addition to serving to assess the state of the coronary arteries. It is an invasive method with a not inconsiderable percentage of complications so it should only be used in these cases.

Treatment of aortic regurgitation

However, if there is heart failure, treatment should be carried out with saline restriction, diuretics, digitalis, and ACE inhibitors. Digitalis can also be used in patients with severe failure and a dilated left ventricle but without symptoms of heart failure.

The appearance of arrhythmias and infections are poorly tolerated by these patients, who may suffer from lung edema, so they must be energetically treated.

If angina appears, it should be treated with nitroglycerin and long-acting nitrates, although they generally do not give very good results.

If aortic valve regurgitation is due to aortic syphilis, the patient should receive a full course of penicillin.

Surgery is the treatment of choice in these patients. It should be indicated before heart failure develops because valve replacement does not restore normal function. It is generally recommended for asymptomatic patients but with progressive left ventricular dysfunction.

The most appropriate intervention is the replacement of the aortic by a mechanical or biological prosthesis according to the patient’s conditions. Only when the insufficiency is due to a dilation of the aortic root can a repair technique be performed without the need to replace the valve, this technique consists of narrowing the annulus or removing the dilated area to join an area of ​​normal size.

In patients who already have established heart failure, intervention should be considered, although the risk is very high, since medical treatment is ineffective and at least improves the patient’s quality of life.

Acute aortic valve regurgitation requires urgent surgical repair as it is the only possibility of saving the life of the patient.

How can I avoid it?

The most important cause of aortic insufficiency is rheumatic fever, so the best way to prevent it is by treating the streptococcal infection in the pharynx with appropriate antibiotics. In addition, we must avoid the appearance of endocarditis, for which antibiotic prophylaxis should be performed in all invasive procedures indicated by our doctor.

Finally, another preventable cause is syphilis, an infection transmitted by sexual contact that can cause serious long-term complications, so all sexual contact with unstable partners must be carried out with a condom.

All the symptoms of this alteration are alarming enough for us to request a consultation with our doctor (dyspnea, chest pain, edema, palpitations).

The desirable thing would be to reach the diagnosis before symptoms appear, for this whenever a murmur is detected we must request a study by our doctor, also if we suffer from any disease associated with this valve alteration (ankylosing spondylitis, syndrome of Marfan, syphilis) should be screened for this valve disease.