Pulmonary arterial hypertension

Pulmonary arterial hypertension (pulmonary hypertension) occurs when the internal pressure of the pulmonary arteries (arteries that run from the heart to the lungs) exceeds 25 mmHg.

This disease does not mean an increase in blood pressure in the general circulation, they are two independent systems.

Pulmonary hypertension is a disease that occurs when the small pulmonary arteries and capillaries:

• narrow
• are clogged,
• are damaged.

As a result, the blood cannot flow well through the lungs and the pressure inside the pulmonary arteries increases.

If the pressure is increased, the right ventricle of the heart has to work harder to pump the blood to the lungs.
As a result, the heart muscle is overstrained and eventually no longer able to pump the blood.

Pulmonary hypertension is a serious condition that progressively worsens and sometimes leads to death.
Women with pulmonary hypertension have a greater risk of death during pregnancy.
The doctor should advise women with pulmonary hypertension not to become pregnant because:

• increased risk of death,
• Risk to the child.

Normal values for pulmonary arterial pressure
The reference values (or normal values) of pulmonary arterial pressure are 18-25 mmHg, while the normal arterial pressure in the aorta is 80-120 mmHg.

Classification of pulmonary arterial hypertension

1. Acute hypertension is caused by respiratory distress syndrome or pulmonary embolism
2. Chronic hypertension is divided into primary and secondary.
   • Primary hypertension is caused by structural abnormalities of the pulmonary arteries and veins that slow or hinder blood flow.
   • Secondary hypertension stems from cardiac, respiratory or circulatory diseases, such as pulmonary thromboembolism.

Degrees of pulmonary arterial hypertension

The degrees of pulmonary arterial hypertension are based on the pressure values:

• Mild pulmonary hypertension, when the pressure is between 25 and 35 mmHg
• Moderate pulmonary hypertension, when levels are between 35 and 45 mmHg
• Severe (or severe) pulmonary hypertension when levels exceed 45 mmHg.

Types of pulmonary hypertension

The World Health Organization (WHO) has divided pulmonary hypertension into five categories.

1. Group 1 – pulmonary arterial hypertension (PAH). This group includes:

• PAH with unknown (idiopathic) cause, occurs very rarely
• Family or hereditary PAH
• Persistent PAH in infants
• PAH associated with connective tissue diseases, congenital cardiopathies, severe liver disease, infection by HIV or through the use of certain dietary medications.

2. Group 2 – pulmonary hypertension caused by diseases of the left heart such as:

• diseases of left atrium and ventricle: heart failure,
• Defect on aortic or mitral valve.

3. Group 3 – caused by lung diseases leading to hypoxia (lack of oxygen in the blood), such as:

• COPD (chronic obstructive airway disease),
• interstitial lung diseases,
• Sleep apnea.

4. Group 4 – associated with recurrent pulmonary embolism. The blood clots in the pulmonary arteries release substances that lead to vasoconstriction.
5. Group 5 – caused by other diseases, for example:

• Sarcoidosis
• rare diseases such as lymphangioleiomyomatosis (LAM),
• mediastinal fibrosis.

This type may be caused by a tumor that increases pressure in the pulmonary arteries.

Precapillary and postcapillary hypertension

1. Precapillary pulmonary hypertension occurs in the pulmonary arteries and is characterized by an increase in blood resistance to circulation.
2. Postcapillary pulmonary hypertension affects the venous system and the area of the left heart, which can be a defect of the left heart muscle or heart valve.

These disorders are divided into:

• Passive pulmonary hypertension, when the pressure difference between pulmonary arterial pressure and pressure in the left atrium (transpulmonary pressure gradient) is less than 12 mmHg.
• Reactive (disproportionate) pulmonary hypertension when the pressure gradient is greater than 12 mmHg.

Persistent arterial pulmonary hypertension in infants and young children

Before birth, the aortic and pulmonary pressure values of the fetus are the same.
The lungs of the fetus do not need a strong circulation, because breathing does not take place yet.
About the umbilical cord:

• the fetus receives oxygen,
• carbon dioxide is discharged.

The blood vessels of the lungs are still compressed.

• After birth and when the infant begins to breathe, the lungs must carry oxygen to the blood.
• This can happen if:
  the liquid in the alveoli is replaced by air,
• the arteries dilate and the blood is transported to the spreading lungs,
• arterial pressure in the pulmonary arteries drops rapidly by more than 50%.

After a few weeks or months, the child’s pulmonary pressure gradually decreases to the value of pressure in adults. However, if this process does not take place, the child develops persistent arterial hypertension.

Persistent arterial hypertension is a serious condition that is most common in infants born at due date or later. This disease arises due to the lack of dilation of blood vessels in the lungs.

The consequences are:

• increased arterial pressure in the lungs (pulmonary hypertension),
• insufficient blood flow to the lungs,
• Lack of oxygen in the blood: the skin has a bluish color (cyanosis).

The causes of persistent pulmonary hypertension include:

• fetal disorder during childbirth,
• respiratory failure, especially due to lung diseases,
• medications taken during pregnancy (high doses of aspirin).

Symptoms of pulmonary hypertension

At the initial stage, the patient does not necessarily have symptoms.
As the disease progresses, symptoms appear and worsen.
Symptoms of pulmonary hypertension include:

• Shortness of breath (dyspnea), initially when moving, in severe cases also at rest
• Fatigue
• Dizziness or loss of consciousness (syncope)
• Chest pain (angina) or tightness
• Swollen ankles, swollen legs and thick abdomen (ascites)
• Blue discolored lips and skin (cyanosis)
• Strong palpitations
• Tachycardia (accelerated heartbeat))
• Dry cough
• Hemoptysis (cough with blood sputum).

Causes of pulmonary hypertension

• Liver disease. Pulmonary hypertension can occur due to cirrhosis of the liver, because it causes an increase in the pressure of the portal vein (which carries blood from the digestive tract and other organs to the liver).
• Rheumatoid diseases such as scleroderma, rheumatoid arthritis or systemic lupus erythematosus (lupus).
• Lung diseases, including lung tumors, emphysema, pulmonary fibrosis, and chronic obstructive pulmonary disease (COPD).
• Heart disease. For example, disorders of the aortic valve, left heart failure, congestive heart failure, mitral valve problems and congenital heart disease.
• Thromboembolic diseases. A blood clot in a large pulmonary vein can lead to the development of pulmonary hypertension.
• Hemolytic anemia: for example, sickle cell anemia.
• Situations with oxygen starvation. This includes: living at high altitude and sleep apnea.
• Genetic predisposition. In some cases, pulmonary hypertension is hereditary.
• Thyroid stimulating hormone (TSH).
• HIV infection.
• Drug abuse (cocaine, methamphetamine).
• Appetite suppressants (fenfluramine, dexfenfluramine).

If no cause can be identified, the condition is called idiopathic arterial pulmonary hypertension. This species is the heaviest because it has the highest mortality rate.

Diagnosis of pulmonary hypertension

During the round, the doctor performs a physical examination:

• listening to abnormal heart sounds, for example a loud noise above the pulmonary valve,
• examination of the jugular vein on the neck to detect swelling indicating problems of the heart (for example, heart failure) and lungs (COPD),
• examination of abdomen, legs and ankles for fluid retention,
• Examination of the fingernail bed to see if it is bluish discolored.

Examinations for the diagnosis of pulmonary hypertension

1. Electrocardiogram (ECG): records the electrical activity of the heart, there may be an abnormal heart rhythm.
2. Color Doppler sonography of the heart (or echocardiogram): Uses sound waves to show the activity of the right ventricle, measure blood flow through the heart valves, and calculate the systolic pressure of the pulmonary artery.
3. Right heart catheterization: This examination measures arterial pressure (that is, inside the pulmonary artery and the artery coming from the left heart) and detects a possible loss of pressure between the right and left sides of the heart.

Other examinations that the doctor may order include:

Laboratory testing

1. Blood test to evaluate liver and kidney function
2. Analysis of autoantibodies in the blood, such as ANA and ESR due to autoimmune diseases
3. HIV: Detection of human immunodeficiency virus
4. Arterial blood gas analysis (BGA): determines the oxygen in the arterial blood
5. Complete blood count (differential blood count): examination for anemia, increased hemoglobin and infections
6. Natriuretic peptide Type B (BNP): an indication of heart failure

Stress test

• 6-minute running test: determines the level of physical tolerance and oxygen saturation in the blood when walking.

Breath test

• Spirometry and other respiratory function tests: evaluates other diseases such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, etc.
• Polysomnigraphy (or cardio-respiratory monitoring) or nocturnal oximetry: a test for sleep apnea (measures oxygen saturation during the night).

Radiological examinations

• Radiography of the thorax (X-ray): demonstrates whether the right ventricle and pulmonary arteries are dilated.
• Pulmonary scintigram: allows to detect narrowing of the pulmonary arteries.
• CT of the thorax: used to find blood coagles and other lung diseases that contribute to or worsen pulmonary hypertension.

Treatment of pulmonary hypertension

The therapy depends on the individual and the underlying disease. It usually includes:

1. Taking medication
2. Lifestyle and diet changes
3. Surgical intervention

Treatment depends on the severity of pulmonary hypertension and on the individual tolerability of the drugs.

The standard therapy for patients with pulmonary hypertension provides:

• Oxygen therapy — improving oxygen saturation in the blood.
• Anticoagulants or “blood thinners” such as Coumadin – preventing blood clots from forming.
• Diuretics such as furosemide (Lasix ®), spironolactone (Aldactones ®) — remove excess fluid from tissues, reduce swelling and make breathing easier.
• Potassium (such as K major ®) — recycles potassium, which is lost with increasing micturition when taking diuretics.

Depending on the severity of hypertension, the doctor may prescribe other medications, including:

1) Vasodilators/calcium antagonists such as nifedipine (Adalate ®), diltiazem and nitric oxide — these lower arterial pulmonary pressure and this can improve the pumping performance of the left ventricle of the heart.

2) Medications for pulmonary hypertension such as:

• Endothelial receptor antagonists – bosentan (Tracleer ® ), make it possible to block the action of endothelin, a substance that causes narrowing of blood vessels in the lungs.
• Prostanoids – epoprostenol (Flolan ®), dilate the pulmonary arteries and help prevent the formation of blood coagles.
• Phosphodiesterase-5 inhibitors – sildenafil citrate (Revatio ®), relax the pulmonary smooth muscle cells and cause pulmonary arteries to widen.

Treatment of infants with pulmonary hypertension

• oxygen administration to dilate the pulmonary arteries;
• ventilation to facilitate the expansion of the lungs;
• Extracorporeal membrane oxygenation (ECMO) in newborns who do not respond to therapy.

Surgery for pulmonary arterial hypertension

• Pulmonary thromboendarterectomy: If there is a large coagel of blood in a pulmonary artery, it can be surgically removed to improve lung function and circulation.
• Lung transplantation: Currently, this is the only treatment for primary pulmonary hypertension.
• Transplantation is reserved for advanced pulmonary hypertension that does not respond to therapy.
• After the procedure, the right side of the heart returns to normality.
• Heart/lung transplantation: This type of double transplant is very rare, but is required in patients who have pulmonary insufficiency and left heart failure.

Natural remedies for pulmonary arterial hypertension

Diet and nutrition

Doctors advise:

• Follow a low-salt (sodium) diet
• Do not drink alcohol
• Eat slowly

Lifestyle
changes Doctors recommend:

• Light physical activity
• Control body weight
• Do not smoke, the smoke leads to narrowing of the blood vessels
• Do not go into the mountains, because the oxygen content is too low, especially above 2500 meters altitude.

How long do you live? Prognosis of the patient with pulmonary arterial hypertension

Life expectancy in pulmonary hypertension depends on the cause. Some conditions that cause pulmonary hypertension may improve over time and under treatment.
Pulmonary arterial hypertension is a very severe progressive disease, in fact, the 5-year survival rate is 40%.

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