Pulmonary hypertension (PH) is a serious condition in which the blood pressure in the arteries of the lungs is abnormally elevated. Over time, this increased pressure forces the right side of the heart to work harder and harder to pump blood through the lungs — eventually leading to right heart failure if left untreated.
Despite affecting an estimated 1% of the global population — and up to 10% of adults over 65 — pulmonary hypertension remains widely underdiagnosed. Symptoms overlap with far more common conditions like asthma, COPD, and deconditioning, and the average patient waits 2 to 4 years from the onset of symptoms before receiving a correct diagnosis. That delay matters: early diagnosis improves five-year survival by 42%.
What Is Pulmonary Hypertension?
Normal blood pressure in the pulmonary arteries is low — much lower than the systemic blood pressure measured in your arm. In 2022, the European Society of Cardiology updated the definition of pulmonary hypertension to a mean pulmonary artery pressure (mPAP) greater than 20 mmHg, measured by right heart catheterization at rest. This replaced the older threshold of 25 mmHg, reflecting evidence that pressures even modestly above normal carry prognostic significance.
Understanding PH starts with understanding that it is not a single disease — it is a hemodynamic consequence that can result from many different underlying conditions. The World Health Organization classifies PH into five groups based on the underlying cause, because treatment differs dramatically depending on the type.
The 5 WHO Groups of Pulmonary Hypertension
Group 1: Pulmonary Arterial Hypertension (PAH)
PAH is a disease of the small pulmonary arteries themselves. The vessel walls thicken, stiffen, and remodel, progressively narrowing the lumen and increasing resistance. Causes include idiopathic PAH (no identifiable cause), heritable PAH, drug- or toxin-induced PAH, and PAH associated with connective tissue diseases (particularly scleroderma), congenital heart disease, portal hypertension, and HIV infection.
Group 1 is the type for which the most treatments exist — more than a dozen FDA-approved medications across five drug classes — and the type where the most dramatic therapeutic advances have occurred in recent years.
Group 2: PH Due to Left Heart Disease
This is the most common form of pulmonary hypertension overall. Conditions like heart failure (both with reduced and preserved ejection fraction), valvular heart disease, and chronic left-sided heart conditions cause elevated pressures to back up into the pulmonary circulation. Treatment centers on managing the underlying cardiac condition. Importantly, PAH-specific medications are not approved for Group 2 and can cause harm if used inappropriately.
Group 3: PH Due to Lung Disease or Hypoxia
Chronic lung diseases — including COPD, interstitial lung disease (ILD), and obstructive sleep apnea (OSA) — can cause pulmonary hypertension through chronic low oxygen levels and structural changes to the lung vasculature. An estimated 54% of Group 3 PH patients also have obstructive sleep apnea, making sleep evaluation an important part of the workup.
Treatment focuses on optimizing the underlying lung disease, supplemental oxygen, CPAP or BiPAP for sleep apnea, and pulmonary rehabilitation. This is where PulmoCrit's combined pulmonary and sleep medicine expertise is particularly relevant — we evaluate and treat both sides of the equation.
Group 4: Chronic Thromboembolic PH (CTEPH)
CTEPH develops when blood clots in the pulmonary arteries fail to resolve after a pulmonary embolism, leaving organized scar tissue that obstructs blood flow. It is the only form of PH that is potentially curable — through a surgical procedure called pulmonary thromboendarterectomy (PTE). For patients who are not surgical candidates, balloon pulmonary angioplasty (BPA) and the medication riociguat (Adempas) are available options.
Group 5: PH with Unclear or Multifactorial Mechanisms
This category includes PH associated with hematologic disorders (such as sickle cell disease and myeloproliferative disorders), systemic conditions (sarcoidosis, Langerhans cell histiocytosis), metabolic disorders, and other rare causes. Treatment is directed at the underlying condition.
Symptoms: Why PH Is So Easy to Miss
The earliest and most common symptom of pulmonary hypertension is shortness of breath with exertion — initially during physical activity, and gradually progressing to occur with minimal effort or at rest. Because this symptom is shared with dozens of more common conditions, patients and physicians alike often attribute it to aging, weight gain, deconditioning, or asthma before PH is considered.
Other symptoms include:
- Fatigue and weakness — often the first symptom patients notice, and frequently dismissed
- Dizziness or lightheadedness — especially with exertion or standing
- Chest pain or pressure — particularly during activity
- Palpitations — a rapid or irregular heartbeat
- Swelling in the ankles, legs, or abdomen — a sign that the right heart is struggling
- Syncope (fainting) — a concerning sign of advanced disease
- Cyanosis — bluish discoloration of the lips or fingertips
A key warning sign: If you find yourself becoming progressively more limited in your activities — avoiding stairs, resting more frequently during walks, or feeling winded doing things that used to be easy — and especially if you also notice ankle swelling or lightheadedness, ask your doctor about a pulmonary hypertension evaluation. The earlier PH is caught, the more effective treatment can be.
How Pulmonary Hypertension Is Diagnosed
Diagnosis typically begins with a transthoracic echocardiogram — an ultrasound of the heart that can estimate pulmonary artery pressures noninvasively. Echocardiography is the best screening tool for PH: it can estimate pulmonary artery systolic pressure (PASP) through the tricuspid regurgitation jet and identify signs of right ventricular strain.
However, echocardiography is a screening tool, not a diagnostic one. Right heart catheterization (RHC) remains the gold standard for confirming the diagnosis. During this procedure, a thin catheter is threaded through a vein (typically the internal jugular or femoral vein) into the right side of the heart and pulmonary arteries, allowing direct measurement of:
- Mean pulmonary artery pressure (mPAP) — the defining measurement; >20 mmHg confirms PH
- Pulmonary vascular resistance (PVR) — >2 Wood units indicates pre-capillary PH (Groups 1, 3, 4, 5)
- Pulmonary artery wedge pressure (PAWP) — helps distinguish pre-capillary from post-capillary (Group 2) PH
- Cardiac output — assesses how well the right heart is compensating
Additional diagnostic tests typically include pulmonary function tests (PFTs), chest CT or HRCT, ventilation-perfusion (V/Q) scan (to rule out CTEPH), blood work for connective tissue diseases and HIV, an overnight sleep study to evaluate for sleep apnea, and a six-minute walk test to quantify exercise capacity.
Vasoreactivity Testing
In patients with Group 1 PAH, a vasoreactivity test is performed during the right heart catheterization. The patient inhales nitric oxide (or receives another vasodilator), and the response is measured. The roughly 10% of PAH patients who are "vasoreactive" may respond to calcium channel blockers — a far less expensive and simpler treatment than the targeted PAH therapies. This test is a critical step in treatment planning.
Treatment: A Rapidly Evolving Landscape
Treatment for PH depends entirely on the underlying type. The most advanced therapeutic options are for Group 1 (PAH), where more than a dozen FDA-approved medications target the disease through five distinct pathways:
Established Drug Classes
- Endothelin receptor antagonists (ERAs) — bosentan, ambrisentan, macitentan. Block endothelin-1, a potent vasoconstrictor produced in excess in PAH.
- Phosphodiesterase-5 inhibitors (PDE5i) — sildenafil, tadalafil. Enhance the nitric oxide pathway to promote vasodilation in the pulmonary arteries.
- Soluble guanylate cyclase stimulators (sGC) — riociguat. Also targets the nitric oxide pathway but through a different mechanism; also the only approved drug for CTEPH.
- Prostacyclin pathway agents — epoprostenol, treprostinil, iloprost, selexipag. The most potent vasodilators available, delivered via continuous IV infusion, subcutaneous pump, inhalation, or oral formulation.
Sotatercept (Winrevair) — A Breakthrough
The most significant advance in PAH treatment in years is sotatercept (brand name Winrevair), approved by the FDA in March 2024. Unlike all previous PAH drugs — which work by relaxing blood vessels — sotatercept is an activin signaling inhibitor that targets the underlying vascular remodeling process. It is the first PAH therapy that addresses a disease-modifying mechanism rather than just managing symptoms.
Sotatercept is administered as a subcutaneous injection every three weeks and is used in combination with existing background PAH therapies.
ZENITH trial results: In the Phase 3 ZENITH trial — published in the New England Journal of Medicine in March 2025 — sotatercept reduced the risk of death, lung transplantation, or PAH-related hospitalization by 76% compared to placebo in patients with advanced PAH. The trial was stopped early by an independent monitoring committee due to overwhelming efficacy. Events occurred in only 17% of treated patients versus 55% receiving placebo. In October 2025, the FDA expanded the sotatercept label to include this risk reduction indication.
Treatment for Other PH Groups
For Group 2 (left heart disease), treatment focuses on optimizing heart failure management, valvular repair, and diuretics. For Group 3 (lung disease/hypoxia), priorities include treating the underlying lung condition, supplemental oxygen, CPAP/BiPAP for sleep apnea, and pulmonary rehabilitation. For Group 4 (CTEPH), surgical thromboendarterectomy is the treatment of choice when feasible, with riociguat and balloon angioplasty as alternatives.
The Sleep Apnea Connection
Obstructive sleep apnea is both a cause and an aggravating factor in pulmonary hypertension. Chronic intermittent hypoxia during sleep leads to pulmonary vasoconstriction, vascular remodeling, and ultimately elevated pulmonary pressures. Research shows that over half of Group 3 PH patients have concurrent OSA, and PAP therapy compliance is associated with lower pulmonary artery pressures.
This is one of the reasons PulmoCrit's integrated pulmonary and sleep medicine practice model is valuable for PH patients. When we diagnose or evaluate pulmonary hypertension, sleep apnea screening is part of the standard workup. And when we diagnose sleep apnea, we look for signs of elevated pulmonary pressures. Many practices separate these evaluations — we don't.
Living with Pulmonary Hypertension
The prognosis for pulmonary hypertension has improved dramatically over the past two decades. While median survival was once cited as 2.5 years from diagnosis, most patients today are living 7 to 10 years, and some are living 20 years or more with appropriate treatment and follow-up.
Key factors associated with better outcomes include early diagnosis and prompt initiation of treatment, adherence to prescribed medications (including continuous IV prostacyclin therapy when indicated), regular exercise within the limits set by your physician, close monitoring with serial echocardiograms, six-minute walk tests, and periodic right heart catheterizations, and identification and treatment of comorbidities such as sleep apnea and iron deficiency.
When Should You Ask About Pulmonary Hypertension?
Consider discussing PH with your physician or requesting a pulmonary evaluation if you experience:
- Progressive shortness of breath that limits your daily activities
- Unexplained fatigue or exercise intolerance that is worsening over time
- Swelling in your legs, ankles, or abdomen
- Lightheadedness or fainting, especially with exertion
- An echocardiogram showing elevated estimated pulmonary pressures or right ventricular enlargement
- A connective tissue disease (particularly scleroderma) with new respiratory symptoms
- A history of blood clots in the lungs (pulmonary embolism) with persistent symptoms
- Severe COPD, ILD, or sleep apnea with signs of right heart strain
PulmoCrit's physicians evaluate and manage all five groups of pulmonary hypertension. We offer in-house pulmonary function testing, echocardiography coordination, sleep apnea screening at our PC Sleep Center, six-minute walk testing, and close follow-up with right heart catheterization when indicated. For patients requiring advanced PAH therapies, we coordinate with specialized PH centers and transplant programs as needed.
Concerned About Pulmonary Hypertension?
Our board-certified pulmonologists diagnose and manage all types of pulmonary hypertension, with integrated sleep medicine expertise to address the sleep apnea–PH connection. Comprehensive evaluation available at our Granada Hills, Encino, and Thousand Oaks offices.
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