PAH – Types, Causes

Pulmonary arterial hypertension (PAH) is a type of pulmonary hypertension in which the blood pressure in the arteries of the lungs becomes abnormally high. In PAH, the pulmonary arteries become narrowed, thickened, or damaged, making it difficult for blood to flow through the lungs. As a result, the heart has to work harder to pump blood, which can strain the heart over time.

Types of Pulmonary Arterial Hypertension (PAH)

The common types of pulmonary arterial hypertension (PAH) include:

• Idiopathic PAH (IPAH): A form of PAH with no known cause. It develops gradually and affects the small blood vessels in the lungs.
• Heritable PAH (HPAH): A genetic form of PAH caused by inherited gene mutations or a family history of the condition. It increases resistance in the pulmonary arteries and can lead to right-sided heart failure.
• Drug- and Toxin-Induced PAH: This type of PAH is caused by certain medications, drugs, or toxins that damage the blood vessels in the lungs, leading to increased pulmonary blood pressure.

Measuring Blood Pressure in PAH

Blood pressure is commonly measured using a blood pressure cuff and is recorded in millimeters of mercury (mm Hg). A blood pressure reading has two numbers:

• Systolic pressure: The higher number that measures pressure when the heart beats.
• Diastolic pressure: The lower number that measures pressure when the heart rests between beats.

A normal blood pressure reading is usually around 120/80 mm Hg.

In pulmonary arterial hypertension (PAH), doctors measure the pressure in the pulmonary arteries, which carry blood from the heart to the lungs. This is called pulmonary artery pressure (PAP). Normal PAP at rest ranges from 8 to 20 mm Hg. Pulmonary pressure is considered elevated if it is greater than 25 mm Hg at rest or above 30 mm Hg during physical activity.

How Does PAH Affect Your Heart and Lung Arteries?

Pulmonary arterial hypertension (PAH) makes it harder for blood to flow through the arteries in the lungs because these blood vessels become narrowed, thickened, or damaged. As a result, the heart must work harder than normal to pump blood through the lungs.

Over time, this extra strain causes the right side of the heart to enlarge and thicken. Eventually, the heart may become weaker and less effective at pumping blood throughout the body, which can lead to serious complications such as right-sided heart failure.

Symptoms of Pulmonary Arterial Hypertension (PAH)

Common symptoms of pulmonary arterial hypertension (PAH) include:

• Shortness of breath during daily activities
• Fatigue or weakness
• Chest pain or chest tightness
• Rapid or racing heartbeat
• Pain in the upper right side of the abdomen
• Loss of appetite
• Wheezing or coughing
• Dizziness or lightheadedness, especially during physical activity
• Fainting (syncope)
• Swelling in the ankles, legs, or feet

Causes of Pulmonary Arterial Hypertension (PAH)

Several medical conditions and factors can contribute to the development of pulmonary arterial hypertension (PAH), including:

• Autoimmune diseases such as scleroderma and rheumatoid arthritis
• Congenital heart defects (heart defects present at birth)
• Pulmonary embolism (blood clots in the lungs)
• Left-sided heart failure
• Heart valve disease
• HIV infection
• Long-term low oxygen levels in the blood
• Chronic lung diseases such as COPD and pulmonary fibrosis
• Chronic pulmonary disorders
• Certain medicines and drugs, including some appetite suppressants or diet pills
• Obstructive sleep apnea (OSA)

How Is Pulmonary Arterial Hypertension (PAH) Diagnosed?

Pulmonary arterial hypertension (PAH) can be difficult to diagnose because its symptoms are similar to those of other heart and lung conditions. Doctors usually perform several tests to confirm the condition and rule out other possible causes. These tests are typically carried out by a pulmonologist (lung specialist) and a cardiologist (heart specialist).

Common Tests Used to Diagnose PAH

• Blood Tests: Used to check for conditions linked to PAH, including HIV, thyroid disorders, autoimmune diseases (such as lupus, scleroderma, and rheumatoid arthritis), liver problems, and other abnormalities.
• Electrocardiogram (ECG/EKG): Records the electrical activity of the heart and may help detect irregular heart rhythms or signs of strain on the right side of the heart.
• Lung Function Tests: Evaluate how well the lungs work and help identify conditions such as asthma or COPD.
• 6-Minute Walk Test: Measures exercise capacity by checking how far a person can walk in six minutes and whether oxygen levels decrease during activity.
• Echocardiogram: An ultrasound scan of the heart used to assess heart structure, heart function, and estimate pulmonary artery pressure.
• Right Heart Catheterization: Considered the gold standard test for diagnosing PAH. A thin catheter is inserted through a vein in the neck, arm, or groin and guided into the right side of the heart and pulmonary artery to directly measure pulmonary blood pressure.

Treatment Methods

Although most kinds of PH have no known cure, there are medications available to help treat PAH. These medications are based on naturally occurring substances in your body that may be out of balance.

Endothelin Receptor Antagonists (ERAs):

These are drugs that are taken orally (by mouth). Endothelin overproduction causes blood vessels to constrict and tighten. This can result in excessive blood pressure in the lungs.

Phosphodiesterase Inhibitors (PDE-5):

These are drugs that are taken orally (by mouth). PDE-5 functions similarly to nitric oxide.

Nitric oxide aids in the relaxation of blood vessels. Low amounts of this can cause pulmonary hypertension.

Medications that increase nitric oxide production in the body to assist relax blood arteries include:

• Sildenafil
• Tadalafil

Prostacyclin:

These medications are classified as:

Inhaled (breathed in) into the body via a catheter (tube) orally (by mouth). Oral prostacyclin are newer PAH medications.

Keeps arteries open so blood can circulate freely. Too little of this in your body may raise blood pressure in your lungs.

Oxygen:

This can aid in the relaxation of blood vessels in the lungs.

Anticoagulants:

They are referred to as “blood thinners.” These are occasionally used to treat blood clots in the lungs.

Diuretics:

Also known as “water pills.” These are used to reduce edema in the belly, legs, or foot.

Prevent difficulties throughout your life.

Your doctor may advise you to take the following to help prevent some of the problems of pulmonary hypertension.

• If your pulmonary hypertension is caused by heart failure or high blood pressure, make heart-healthy lifestyle adjustments such as heart-healthy nutrition.
• Participate in frequent physical activity. Consult your doctor before beginning any fitness program to determine the right level of physical exercise for you.
• Avoid high altitudes if possible, and consult your doctor about any plans for air travel or visits to high-altitude regions.
• If you intend to become pregnant, consult your doctor because there is an elevated risk of pregnancy difficulties.
• Treat additional medical issues such as COPD, heart disease, and Narcolepsy.

Frequently Asked Questions (FAQs)

Q1) What is the life expectancy of someone with pulmonary arterial hypertension (PAH)?

Ans: Life expectancy depends on the type and severity of pulmonary hypertension, overall health, and response to treatment. With early diagnosis and proper treatment, many people with PAH can live for several years after diagnosis.

Q2) What is the main cause of pulmonary hypertension?

Ans: Pulmonary hypertension can be caused by congenital heart disease, connective tissue disorders, chronic lung diseases, blood clots in the lungs, liver disease, left-sided heart disease, and certain medications.

Q3) What are the 4 stages of pulmonary hypertension?

Ans: Pulmonary hypertension is commonly classified into four functional classes:

• Class 1: No limitation during physical activity
• Class 2: Mild limitation during physical activity
• Class 3: Significant limitation during physical activity
• Class 4: Symptoms occur even at rest and physical activity becomes difficult

Q4) Can pulmonary hypertension go away?

Ans: Pulmonary hypertension usually cannot be completely cured, but treatment can help control symptoms, improve quality of life, and slow disease progression.

Q5) What should I avoid if I have pulmonary arterial hypertension?

Ans: People with PAH should avoid high-sodium foods, smoking, excessive physical strain, and activities at high altitude. Processed foods, canned foods, deli meats, and frozen meals should also be limited.

Q6) What test confirms pulmonary arterial hypertension?

Ans: Right heart catheterization is considered the gold standard test for confirming PAH. Echocardiography is also commonly used to estimate pulmonary artery pressure.

Q7) What is the difference between pulmonary hypertension and pulmonary arterial hypertension?

Ans: Pulmonary hypertension is a broad term for high blood pressure in the lungs, while pulmonary arterial hypertension (PAH) is a specific type caused by narrowing and damage to the small pulmonary arteries.

Q8) At what age does pulmonary arterial hypertension occur?

Ans: PAH can occur at any age, but it is most commonly diagnosed in adults between 30 and 60 years old. Women are affected more often than men.

Q9) Is drinking water good for pulmonary arterial hypertension?

Ans: Proper hydration is important, but excessive fluid intake may worsen symptoms in some patients. Fluid intake recommendations should be followed according to a doctor’s advice.

Q10) What are the symptoms of end-stage pulmonary arterial hypertension?

Ans: End-stage PAH may cause severe shortness of breath, chest pain, fatigue, fluid retention, dizziness, fainting, and low oxygen levels due to worsening heart and lung function.