OVERVIEW

What is pulmonary artery pressure in pulmonary hypertension?

The pulmonary artery is similar to the brachial artery where blood pressure is typically measured in the arm, as both reflect the resistance encountered by the heart when pumping blood to some extent.

The difference is that the brachial artery reflects the resistance faced by the left ventricle, commonly known as blood pressure, while the pulmonary artery reflects the resistance encountered by the right ventricle, primarily indicating "arteriosclerosis" of the lungs caused by pulmonary vascular diseases or chronic lung conditions.

Additionally, since blood in the pulmonary artery only circulates within the lungs over a short distance, the pressure is much lower than systemic blood pressure. However, precise measurement requires specialized invasive testing methods.

What is pulmonary hypertension?

When measuring blood pressure, we know that a systolic pressure above 140 mmHg and/or a diastolic pressure above 90 mmHg indicates hypertension. Similarly, pulmonary artery pressure can also vary. If the systolic pulmonary artery pressure exceeds 30 mmHg or the diastolic pressure exceeds 15 mmHg, it is considered abnormally high.

The clinical standard for diagnosing pulmonary hypertension is based on the mean pulmonary artery pressure during both systole and diastole. A mean pulmonary artery pressure above 25 mmHg at rest is defined as pulmonary hypertension.

In such cases, individuals often experience shortness of breath and fatigue after activity, and in severe cases, these symptoms may persist even at rest.

What are the types of pulmonary hypertension?

WHO classifies pulmonary hypertension into 5 types based on etiology:

• Type 1: Pulmonary arterial hypertension (PAH);

• Type 2: Pulmonary hypertension due to left heart disease;

• Type 3: Pulmonary hypertension caused by chronic lung diseases and/or hypoxia;

• Type 4: Chronic thromboembolic pulmonary hypertension (CTEPH);

• Type 5: Pulmonary hypertension with unclear multifactorial mechanisms.

SYMPTOMS

How is pulmonary hypertension classified?

• Mild pulmonary hypertension: Mean pulmonary artery pressure 25–36 mmHg, systolic pulmonary artery pressure 31–40 mmHg.

• Moderate pulmonary hypertension: Mean pulmonary artery pressure 37–45 mmHg, systolic pulmonary artery pressure 41–70 mmHg.

• Severe pulmonary hypertension: Mean pulmonary artery pressure >45 mmHg, systolic pulmonary artery pressure >70 mmHg.

Classification helps assess disease progression and guide treatment.

How is functional classification determined for pulmonary hypertension?

World Health Organization (WHO) functional classification for pulmonary hypertension patients:

• Class I: No limitation in physical activity. Ordinary activity does not cause dyspnea, fatigue, chest pain, or syncope.

• Class II: Slight limitation in physical activity. Comfortable at rest, but ordinary activity causes dyspnea, fatigue, chest pain, or syncope.

• Class III: Marked limitation in physical activity. Comfortable at rest, but mild activity causes dyspnea, fatigue, chest pain, or syncope.

• Class IV: Unable to perform any physical activity. Signs of right heart failure may be present. Symptoms like dyspnea or fatigue occur at rest and worsen with any activity.

What symptoms do pulmonary hypertension patients experience?

Main symptoms include dyspnea, fatigue, and in severe cases, syncope during exertion, angina, hemoptysis, hoarseness, and signs of right heart failure such as loss of appetite, abdominal distension, lower limb edema, and hepatosplenomegaly.

Why does pulmonary hypertension cause dyspnea?

To understand dyspnea, consider the lungs as a "logistics hub." Smooth breathing depends on three factors: sufficient oxygen ("cargo"), efficient gas exchange ("loading/unloading"), and unobstructed blood flow ("transport fleet").

• Oxygen (cargo): Shortage leads to dyspnea.

• Gas exchange (loading/unloading): Impaired exchange due to lung diseases causes dyspnea.

• Blood flow (transport fleet): Obstruction in pulmonary circulation (e.g., pulmonary hypertension) disrupts oxygen delivery, causing dyspnea.

Pulmonary hypertension primarily affects the third factor, though severe cases may also involve gas exchange impairment.

Why do pulmonary hypertension patients feel fatigued or experience syncope?

The pulmonary circulation is the body’s "supply chain." Pulmonary hypertension obstructs oxygen delivery ("supplies"). During exertion, oxygen demand increases, but insufficient supply causes fatigue. Severe cases may show symptoms even at rest.

Syncope occurs because muscles prioritize oxygen during exercise, leaving the brain deprived.

Why does pulmonary hypertension cause angina?

When oxygen delivery is impaired, the body reflexively increases heart workload (contractility and rate). However, the heart itself receives less oxygen, creating a "work more, eat less" scenario, leading to angina.

Why does pulmonary hypertension cause hemoptysis?

Elevated pressure in thin-walled pulmonary vessels (due to venous or lung diseases) may rupture them, allowing blood into alveoli. Coughing expels this blood as hemoptysis.

Why does pulmonary hypertension cause hoarseness?

Increased pulmonary artery pressure dilates the artery, compressing the nearby recurrent laryngeal nerve, resulting in hoarseness.

Why does pulmonary hypertension lead to right heart failure?

Chronic pressure overload exhausts the right ventricle, reducing its pumping efficiency. Blood backs up in veins, causing systemic congestion (e.g., appetite loss, abdominal distension, hepatosplenomegaly, edema). Paradoxically, pulmonary pressure may decrease as the right heart fails—a poor prognostic sign.

Why is pulmonary hypertension called "the cancer of cardiovascular diseases"?

Pulmonary hypertension involves progressive small-vessel lung damage, often untreatable. It is highly malignant, with a mean onset age of 36. 75% of patients are aged 20–40, and 15% are under 20 (even children). Its prognosis is catastrophic, akin to cancer.

Why does pulmonary hypertension cause right ventricular hypertrophy?

The right ventricle works harder to overcome pulmonary resistance, leading to hypertrophy and dilation. Eventually, this compensatory mechanism fails, causing right heart failure and its associated symptoms.

CAUSES

What are the causes of pulmonary hypertension?

Identifying the causes of pulmonary hypertension helps clarify its clinical types:

• Arterial pulmonary hypertension: Caused by issues originating in the pulmonary arteries themselves, such as idiopathic pulmonary hypertension, hereditary pulmonary hypertension, drug- or toxin-induced pulmonary hypertension, or congenital heart disease-related pulmonary hypertension.

• Lung disease-associated pulmonary hypertension: Easily understood—lung diseases hinder blood flow through the pulmonary arteries (for gas exchange), leading to increased pulmonary artery pressure. Examples include chronic obstructive pulmonary disease (COPD), interstitial lung disease, and tuberculosis.

• Pulmonary venous occlusive hypertension: Blood ejected by the right ventricle into the pulmonary arteries flows to the pulmonary veins after gas exchange. If the pulmonary veins narrow (e.g., post-radiofrequency ablation), blood return is obstructed, causing pulmonary hypertension.

• Left heart dysfunction-related pulmonary hypertension: The endpoint of pulmonary circulation is the left ventricle. Left heart failure impedes pulmonary blood return, inevitably leading to pulmonary hypertension. These four causes act like checkpoints—obstruction at any point triggers pulmonary hypertension.

• Chronic thromboembolic pulmonary hypertension: For example, in patients with deep vein thrombosis, dislodged clots can cause pulmonary embolism, abruptly raising pulmonary artery pressure. This condition is typically acute and easily identifiable.

• Other causes: Such as hematologic diseases or certain malignancies.

Can pulmonary hypertension be caused by radiofrequency ablation?

Radiofrequency ablation is a common interventional treatment for tachyarrhythmias, including atrial tachycardia, paroxysmal supraventricular tachycardia, atrial fibrillation, and ventricular tachycardia.

Using catheters inserted via the femoral vein or artery, electrical energy is converted to heat to damage specific heart tissues, disrupting abnormal conduction or excitability. Since atrial fibrillation ablation often targets areas near the pulmonary veins, post-procedural scarring may cause pulmonary vein stenosis, contributing to pulmonary hypertension.

Why is pulmonary hypertension commonly linked to congenital heart disease?

• Congenital heart defects severely impact pulmonary vascular development. For example, ventricular septal defects increase fetal pulmonary blood flow, altering pulmonary vascular structure at birth and predisposing to pulmonary hypertension.

• Patients with congenital heart defects often experience progressive increases in pulmonary vascular resistance. Early surgical correction may reverse vascular changes, but delayed intervention leads to irreversible damage, escalating pulmonary pressure and compromising quality of life and longevity.

• The likelihood and severity of pulmonary hypertension depend on the nature of the defect.

How can improper use of weight-loss drugs cause pulmonary hypertension?

Certain weight-loss drugs suppress appetite but also disrupt the serotonin transport system.

This disruption imbalances pulmonary vascular endothelial cell growth, increasing endothelin (a pulmonary vasoconstrictor) secretion and elevating pulmonary artery pressure.

Clinical data show pulmonary hypertension is 4 times more prevalent in women than men. Among appetite suppressant users, its incidence is 25–50 times higher than in the general population.

DIAGNOSIS

What tests should be done for pulmonary hypertension?

• Echocardiography.

• Right heart catheterization.

• Chest X-ray: To assess the degree of pulmonary artery dilation and general lung condition.

• Electrocardiogram (ECG): To indirectly evaluate right atrial or ventricular enlargement and arrhythmias.

• Complete blood count (CBC): To check for secondary polycythemia.

• Pulmonary function tests: To assess respiratory function.

• Sleep apnea monitoring and pulmonary angiography.

Why can echocardiography estimate pulmonary artery pressure in pulmonary hypertension?

Echocardiography is a non-invasive screening tool for suspected pulmonary hypertension. It estimates pressure based on blood regurgitation velocity across heart valves. While less accurate than invasive methods, it is safer and more economical.

What other important values does echocardiography provide for pulmonary hypertension patients?

Beyond estimating pulmonary artery pressure, echocardiography detects right ventricular hypertrophy/dilation, underlying conditions (e.g., congenital heart disease), and pulmonary artery dilation.

What is right heart catheterization for pulmonary hypertension?

As the gold standard for diagnosis, this invasive procedure involves inserting a pressure-measuring catheter via the femoral vein into the inferior vena cava → right atrium → right ventricle → pulmonary artery to directly monitor pressures.

Is anesthesia required for right heart catheterization in pulmonary hypertension?

Adults typically require local anesthesia only. Children need general anesthesia and must fast to avoid aspiration pneumonia from vomiting.

When is sleep apnea monitoring needed for pulmonary hypertension?

For patients with severe snoring or apnea, monitoring nocturnal vitals and apnea events helps diagnose sleep apnea syndrome and guide treatment.

When is pulmonary angiography necessary for pulmonary hypertension?

For acute-onset chest pain, dyspnea, or hemoptysis with prior venous insufficiency, angiography confirms pulmonary embolism for prompt treatment.

Why is identifying high-risk groups critical in pulmonary hypertension prevention?

Since symptoms are often irreversible, early screening via echocardiography is vital for high-risk populations:

• Chronic lung disease patients
• Congenital heart disease patients
• Appetite suppressant users
• Familial idiopathic pulmonary hypertension
• Connective tissue disorder patients (e.g., rheumatoid arthritis, lupus)

Which pulmonary hypertension patients have <1 year life expectancy?

• Right atrial pressure >20 mmHg on catheterization
• Mean pulmonary artery pressure >85 mmHg on catheterization
• Overt right heart failure
• WHO functional class III-IV

TREATMENT

Which department should I visit to confirm a diagnosis of pulmonary hypertension?

If pulmonary hypertension is suspected, you should immediately visit the cardiovascular medicine or cardiovascular surgery outpatient department for examination. A specialist will determine whether hospitalization is needed for a right heart catheterization based on your symptoms and auxiliary tests such as echocardiography and electrocardiogram.

What is the drug treatment for pulmonary hypertension after diagnosis?

After diagnosis, pulmonary hypertension is difficult to cure, but proper medication can stabilize the condition and improve the patient's quality of life and lifespan.

• Epoprostenol: A newly developed formulation that has become the "gold standard" for treating pulmonary hypertension, especially effective for primary pulmonary hypertension.

• Bosentan: Endothelin is a potent endogenous vasoconstrictor, and bosentan is an endothelin receptor antagonist. It is effective in treating pulmonary hypertension but extremely expensive.

• Nitroglycerin: Can be used during episodes for patients experiencing angina.

• Calcium channel blockers: Such as nifedipine and diltiazem. They relax vascular smooth muscle to reduce pulmonary artery pressure, but their effectiveness is limited.

In addition, based on the condition assessment, patients may need to take anticoagulants regularly, and home oxygen therapy is highly recommended.

What surgical treatments are available for pulmonary hypertension?

• Atrial septostomy: Essentially creating a hole between the left and right atria to relieve right heart pressure, similar to flood diversion.

• Heart-lung transplantation: This is the ultimate treatment for pulmonary hypertension, but due to ethical reasons, it is rarely reported.

How can treatment costs for pulmonary hypertension be reduced?

Since medications for pulmonary hypertension are very expensive, eligible patients can apply for subsidy programs from the China Charity Federation, reducing monthly drug costs from over 20,000 yuan to around 4,000 yuan. Patients can inquire at local hospitals or search online for detailed application terms.

What is the life expectancy for patients with pulmonary hypertension?

About 75% of pulmonary hypertension patients die within five years of diagnosis, with an average survival time of 1.9 years after symptom onset. Those with right heart failure have an even shorter survival time. However, with advances in treatment, survival rates are gradually improving. Early diagnosis and treatment can stabilize the condition in over 20% of patients.

DIET & LIFESTYLE

Can Women with Pulmonary Hypertension Have Children?

For female patients with pulmonary hypertension in their childbearing years, the most pressing concern is whether they can conceive and give birth. The answer, however, is a firm no. This is because pregnancy poses a life-threatening risk to women with pulmonary hypertension.

From the first trimester of pregnancy, blood flow through the pulmonary arteries increases, raising pulmonary artery pressure and placing additional strain on the heart. The condition may worsen during pregnancy and childbirth.

Although there have been reports of patients successfully conceiving and delivering, pregnancy and childbirth typically exacerbate pulmonary hypertension and can even lead to death. The mortality rate for patients with severe pulmonary hypertension is as high as 30% to 50%.

Even for those who survive, the increased pulmonary artery pressure during pregnancy does not improve after delivery. Where legally permitted, assisted reproductive technologies may offer some hope.

PREVENTION

How should high-risk groups for pulmonary hypertension prevent it?

• Boost immunity, avoid respiratory infections, and actively treat underlying lung diseases for patients with pre-existing pulmonary conditions.

• Young women should undergo thorough examinations and evaluations before pregnancy.

• Patients with congenital heart disease should actively pursue interventional closure or surgical treatment.

• Strictly avoid the misuse of weight-loss drugs. Those who must take them should do so under medical supervision.

• Schedule regular cardiac ultrasound examinations.

• High-risk individuals should seek immediate medical attention if they experience discomfort and inform their doctor about their high-risk status for pulmonary hypertension.