What is aortic insufficiency
With the term aortic insufficiency we mean a pathology affecting the aortic valve, a branch of communication between the heart and the body, for which this is not able to close perfectly causing a reflux (in technical term defined as regurgitation) of blood in the left ventricle. For this reason we can often speak of aortic insufficiency or aortic regurgitation indifferently. Less common pathology than aortic stenosis and mitral regurgitation, its incidence increases with age, and does not show a different prevalence in both sexes.
Anatomy of the aortic valve
The aortic valve is one of the four heart valves (the other three are the tricuspid, mitral, and pulmonary valves) that coordinate the heart in doing its job of pumping blood around the body. More in detail, the cardiac cycle is constituted by the alternation of systole and diastole, respectively two moments in which the blood passes from the atria to the ventricles and from the circulating ventricles; during the ventricular systole phase the aortic valve is open to allow the passage of blood, in diastole it is closed in order to prevent the blood from moving forward instead of going forward, the heart valves have in fact the purpose of giving unidirectionality to the blood . And it is a deficit, therefore aortic valve insufficiency at this point in the cardiac cycle that causes regurgitation.
The aortic valve is called the semilunar valve and consists of three cusps (right coronary, left coronary and posterior or non-coronary) which, when closed, prevent the blood from flowing back, forming three hemispherical swellings with concavity facing upwards called breasts of Valsalva, from which the coronary arteries originate, the main arterial branches of the heart and whose occlusion represents one of the causes of myocardial infarction.
This valvulopathy, on the other hand, can affect the structure of the aorta at different levels, anatomically divided as follows:
- Ascending aorta (Root of the aorta): the sinuses of Valsalva, aortic bulb, aortic sinus;
- Aortic Arch: from which the brachiocephalic trunk (or anonymous artery), L‘common carotid artery left and the subclavian artery yesleft. These arteries supply blood to the head, neck, upper limbs, and upper chest.
Aortic isthmus is the transition point between the aortic and descending arch.
- Descending aorta: in the first section we speak of thoracic aorta instead after the abdominal aorta diaphragm
Causes of aortic insufficiency and predisposing factors
Aortic regurgitation may result from a primary disease of the aortic valve flaps or from abnormalities of the aortic root or ascending aorta. The acute and chronic forms of aortic regurgitation are to be considered as two distinct entities, in fact they have different causes, different presentation, development and treatment.
So now we are going to analyze the different etiologies of aortic insufficiency by distinguishing not only the acute form from the chronic one, but also remembering that in both cases the pathology can affect the valve flaps or the root and the ascending aorta or both.
Etiology of chronic aortic insufficiency
A disease of the valve flaps can lead to aortic regurgitation from inadequate coaptation (ie closure) of the flaps, their perforation or their prolapse.
Pathologies affecting the root of the aorta or ascending aorta cause regurgitation because they cause the flaps to move away from each other, preventing them from closing properly.
Pathologies that affect the flaps of the aorta causing anomalies are:
- Congenital anomalies such as bicuspid aortic valve, the most frequent cause of aortic insufficiency in the Western world;
- Infective endocarditis, inflammation of the innermost lining of the heart, usually from bacterial infection
- Rheumatic Fever or Acute Articular Rheumatism from type A streptococcus, now less and less common in Italy;
- Myxomatous degeneration, alteration of the connective tissue that takes on a gelatinous consistency causing a thickening of the flaps;
- Rheumatic diseases such as: Rheumatoid Arthritis, Lupus Erythematosus, Ankylosing Spondylitis
Abnormalities of the root and ascending aorta are mainly due to:
- Dilation of the Aorta due to age;
- Connective tissue diseases such as: Marfan syndrome, cystic necrosis of the media of the aorta, Ehlers-Danlos syndrome;
- Ankylosing Spondylitis and Reiter's Syndrome (HLAB27);
- Aortitis from Syphilis
- Giant cell arteritis, a type of vasculitis that causes nodular fibrosis in the intima of the arterial wall
Etiology of Acute Aortic Failure
Also in this case we find ourselves having to make a difference between flap or root anomalies.
At the expense of flaps:
- Traumatic rupture;
- Acute Infectious Endocarditis;
Affecting the root and ascending aorta:
- Acute aortic dissection which can lead to ectasia of the aortic bulb,
- Aortic aneurysm of which aortic sclerosis can be a major cause
Symptoms of aortic insufficiency
Chronic aortic insufficiency
It usually remains asymptomatic for a long time.
After the development of left ventricular dysfunction, patients gradually show symptoms of left heart failure due to pulmonary congestion:
- exertional dyspnea (i.e. that difficulty in breathing that occurs after a walk or a more intense effort),
- orthopnea (breathing difficulty that occurs when lying down)
- paroxysmal nocturnal dyspnea (breathing difficulty that occurs when you sleep).
- Over time angina (chest pain), mainly at night, because physiological bradycardia is present during sleep, which causes an increase in blood reflux and strains even more an already compromised ventricle
Acute aortic insufficiency
In this case, however, the patients present symptoms that indicate a sudden deterioration of the hemodynamic balance of the heart, therefore
- weakness, altered mental status,
- syncope (fainting).
If left untreated, the patient risks cardiovascular collapse. If these symptoms were to be accompanied by chest or upper back pain, there would be a high suspicion of aortic dissection.
Medically, the following clinical signs are found:
- Pulsus bisferiens o bifidus: occurs when two pulses are felt during a systole, instead of one; the second abnormal pulse could be from reflex rebound of the peripheral arteries or from early diastole due to blood regurgitation;
- Corrigan's Pulse or Water hammer (Pulse celere): wide carotid pulsation, the same phenomenon that occurs when I abruptly close the valve of a water pipe and the shock wave produces a characteristic sound. In the clinic it occurs when the doctor raises the patient's arm and gravity causes the blood to flow back. A faulty valve will cause blood to regurgitate into the ventricles. The reflux of blood into the ventricles will result in a palpable "collapsing" pulse
- Sign of de Musset: simultaneous head oscillations with each beat;
- Quinke's symptom (also called Capillary Pulse): at the level of the nail bed there is an interesting phenomenon of redness and pulsatile paleness when a slight pressure is applied;
- Duroziez's sign: murmur generated by the pressure of a finger on the femoral artery;
- Traube's sign, also called “gunshot”, is a sound that can be heard at the level of the femoral artery
At the auscultatory level, placing the fonend on the chest, the characteristic findings are:
- An early diastolic murmur at high frequency, it is best heard in forced exhalation, the patient is bent forward. It is a type of murmur decreasing in diastole due to the abnormal regurgitation flow.
- There could be a third tone on Erb's focus (3rd intercostal space at the level of the left sternal border);
- Austin Flint murmur is sometimes present, i.e. a diastolic murmur of mitral stenosis due to the inability of the valve to open properly in diastole due to the aortic regurgitation jet
NB We define pulse the heartbeat perceivable in certain points of our body, for example the carotid one.
Classification and severity of aortic insufficiency
Based on the echocardiographic evaluation of the relationship between reflux area / LVOT (outflow tract of the left ventricle), the degree of insufficiency can be established:
- mild aortic insufficiency: <25 % minimally insufficient valve, asymptomatic;
- moderate aortic insufficiency: 25-65 % altered closure mechanism, increased regurgitation can lead to ventricular hypertrophy;
- severe aortic insufficiency:> 65% altered closing mechanism, important symptomatology, potentially fatal.
Diagnosis of aortic insufficiency
First line exams
L'echocardiogram is the key exam to describe:
- the anatomy of the valve, so whether it is bicuspid, tricuspid, unicuspid or quadricuspid
- quantify regurgitation;
- define the morphology of the aorta, evaluating the root of the aorta and the ascending aorta;
- evaluate a possible enlargement of the left ventricle;
- consider whether to proceed with surgery that spares the valve or repairs it.
Thanks to the use of the color Doppler echocardiography technique it will be possible to see whether or not there is the presence of a regurgitation.
L'ECG: left ventricular hypertrophy visible, usually if the disease is advanced;
There chest x-ray (chest x-ray): cardiomegaly can be evaluated only in the most serious cases, not in acute cases. Dilation of the aortic root may also be observed
Second line exams
Cardiac catheterization (or cardiac angiogram): usually it can be useful if there are doubts about the severity of the insufficiency on ultrasound, a catheter is placed in the heart and using the contrast medium I evaluate the cardiac anatomy and in particular if the coronaries, the fundamental vessels for the nourishment of the heart, whether or not they are sick.
Therapy of aortic insufficiency
Acute aortic regurgitation
Indication to perform surgery immediately.
Hemodynamic support (inotropes and nitrates) may be required prior to surgery.
Chronic aortic regurgitation
Treatment of hypertension is recommended in all patients.
Symptomatic patients require surgery and medical therapy cannot be considered a substitute, unless surgery is contraindicated due to the patient's comorbidities.
The definitive treatment of chronic aortic regurgitation is that of valve replacement with surgery that involves mechanical valve implantation if the patient is under 65 and biological in patients over 65. Recall that the implantation of a mechanical valve involves the need for anticoagulant therapy for life. Numerous studies have evaluated the possibility of proceeding only with a repair of the valve and not a complete replacement, but it was found that in the latter case there were fewer complications in the long term.
The indications for surgery are:
- Symptomatic and severe RA;
- Asymptomatic RA with Ejection Fraction (index of overall cardiac function)> 50 % (vn60%)
- patient with significant dilation of the left ventricle;
Another disused surgical possibility is Ross surgery (or pulmonary autotransplantation) is a surgical operation where a diseased aortic valve is replaced with the pulmonary valve of the same patient. The missing valve is replaced with that of a corpse (in this case we speak of an allograft)
Tags: Cardiac surgery Cardiology Heart