What is Pulmonary Hypertension?
Pulmonary hypertension is high blood pressure in the arteries of your lungs, defined as a mean pressure ≥25 mmHg (though newer guidelines suggest >20 mmHg), which forces your heart's right side to work harder and can eventually lead to heart failure and death if untreated. 1, 2
How Your Lungs and Heart Normally Work
- Your heart's right side pumps blood through your lungs to pick up oxygen 3
- Normally, the blood vessels in your lungs are wide and flexible, allowing blood to flow easily with low pressure 4
- After picking up oxygen, blood returns to your heart's left side to be pumped throughout your body 4
What Goes Wrong in Pulmonary Hypertension
The blood vessels in your lungs become narrowed, stiffened, or blocked, making it much harder for blood to flow through them. 3
This happens through several mechanisms:
- The vessel walls thicken and become rigid 3
- The vessels constrict (squeeze down) 5
- Scar tissue or blood clots block the vessels 1, 2
Your heart's right side must pump harder to push blood through these narrowed vessels, eventually causing the right heart muscle to enlarge, weaken, and fail—which is the main cause of death in pulmonary hypertension. 3
The Five Main Types
Pulmonary hypertension is divided into five groups based on what causes it: 1, 2
Group 1: Pulmonary Arterial Hypertension (PAH)
- The small arteries in your lungs become diseased on their own 1, 2
- Can be inherited, caused by certain drugs/toxins, or associated with conditions like HIV, liver disease, or connective tissue diseases 1, 6
- This is the rare form that affects about 1% of the population 6, 3
Group 2: Due to Left Heart Disease
- This is the most common type 6, 2
- Problems with your heart's left side (like heart failure or valve disease) cause blood to back up into your lungs 1, 2
- The increased pressure transmits backward through your lung vessels 4
Group 3: Due to Lung Diseases
- Chronic lung conditions like COPD, scarring of the lungs, or sleep apnea damage lung tissue 1
- Low oxygen levels cause lung vessels to constrict 5
Group 4: Chronic Blood Clots
- Old blood clots remain stuck in your lung arteries and never fully dissolve 1, 2
- These persistent blockages create ongoing high pressure 5
Group 5: Unclear or Multiple Causes
Common Symptoms
The most common symptom is shortness of breath, especially with activity. 1
Other symptoms include:
- Extreme fatigue 1
- Chest pain 1
- Swelling in your ankles and legs 1
- Rapid heartbeat or palpitations 1
- Dizziness or fainting 1
- Bluish color to lips or skin 1
Why This Matters
Without treatment, the median survival for idiopathic pulmonary arterial hypertension was historically only 2.8 years from diagnosis. 2, 5
However, modern treatments have significantly improved outcomes:
- Specific medications are now available for certain types (particularly Group 1 and Group 4) 7
- Early detection and referral to specialized centers is critical 6
- Treatment focuses on the underlying cause for Groups 2,3, and 5 7
How It's Diagnosed
Right heart catheterization—threading a thin tube through your veins into your heart and lung arteries to directly measure pressures—is the gold standard and required for definitive diagnosis. 6, 2
The diagnostic workup typically includes:
- Echocardiogram (ultrasound of your heart) as initial screening 6
- Blood tests to look for underlying causes 1
- Lung function tests 1
- CT scans of your chest 1
- Right heart catheterization for confirmation before starting specific treatments 6, 2
At least 1% of the world's population is affected by some form of pulmonary hypertension, making it more common than many people realize. 3