Pulmonary Hypertension

What is Pulmonary Hypertension?

Pulmonary Hypertension (PULL-mun-airy HI-per-TEN-shun), or PH, is a clinical-physiological syndrome with abnormally high pressure of the blood vessels of the lungs.

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The right side of your heart pumps blood to the pulmonary arteries so it can pick up oxygen. This is a normally a low pressure system, about 15 mmHg at rest. (The mmHg is millimeters of Mercury, the units used to measure systemic blood pressure, like using a cuff on your arm.) The left side of the heart pumps blood to the body and requires a high pressure (average 120 mmHg). With PH, the mean pulmonary artery pressure (PAP) is above 25 mmHg at rest or 30 mmHg during physical activity. This higher pressure makes it harder for the right side of the heart to circulate the blood to the lungs. It can work the heart so much, it causes heart failure.

Types of Pulmonary Hypertension

In 2003, the World Health Organization (WHO) categorized PH into 5 groups, depending upon the cause. Only Group 1 is called pulmonary arterial hypertension (PAH). The others are just pulmonary hypertension.

1.  WHO Group 1 (“arterial”) – Pulmonary Arterial Hypertension (PAH):

  • Idiopathic (IPAH)- unknown cause
  • Familial (FPAH)- inherited
  • Associated with other disease (APAH)- caused by conditions such as: Congenital (at birth) heart disease, Collagen Vascular Disease (like Scleroderma or Rheumatoid Arthritis), HIV infection, portal hypertension, thyroid disease, and certain diet medications (e.g. Fen-Phen) and street drugs (e.g. cocaine)

2.  WHO Group 2 (“venous”) – associated with left heart disease:

  • PH due to left heart disease, like mitral valve disease or long-standing high blood pressure

3.  WHO Group 3 (“hypoxic”) – associated with lung disease or low oxygen:

  • PH due to lung disease, such as COPD or Interstitial Lung Disease
  • PH due to sleep apnea
  • PH due to chronic high altitude
  • PH due to developmental lung conditions

4.  WHO Group 4 (“thromboembolic”) – associated with thrombotic or embolic disease:

  • PH due to pulmonary embolism (blood clots in the lungs)
  • PH due to embolism of other matter, such as cancer cells or parasites

5.  Group 5 (“miscellaneous”) – associated with various other conditions:

  • PH due to various other diseases or conditions, such as Sarcoidosis, Langerhan’s Cell Histiocytosis, and Lymphangioleiomyomatosis (LAM).

Who gets PH?

IPAH is rare- only about a few cases per million people. Women are about 3 times more likely to get it than are men. The other forms of PAH are more common. For example, as many as 50% or more of Scleroderma patients may get PAH and about 10-15% of patients with Systemic Lupus Erythematosis (“lupus”) will get it.

Although usually a more mild form, PH is common in patients with sleep apnea or obesity-hypoventilation syndrome. About 1 in one hundred patients with COPD get PH.

What are the signs and symptoms of Pulmonary Hypertension?

Common symptoms include shortness of breath (especially with exertion), fatigue, chest pain, and racing heartbeat. As the disease progresses, you might develop lightheadedness with exercise, dizziness, fainting, or leg swelling.

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The development of PH can be very  slow. Early on, there may be few symptoms and patients may therefore delay seeing the doctor.

There are 4 classes of severity:

  • Class 1: No limitations
  • Class 2: Slight or mild limitations (such as with regular exercise)
  • Class 3: Marked or noticeable limitations (such as walking 1-2 blocks)
  • Class 4: Severe limitations (such as any activity and sometimes even at rest)

How is PH diagnosed?

Initially, your doctor will need to do a thorough medical and family history, physical examination, and review test results.

The physical exam may reveal abnormal heart sounds, engorged neck veins, heart murmurs, leg swelling, feeling of a pulse over the breast bone, disfigurement of the nailbeds (clubbing), fluid in the abdomen (ascites), or swelling of the spleen or liver.

Medical testing may include blood work, chest x-ray and/or chest CT scan, EKG, overnight oxygen monitoring, arterial blood gases, echocardiogram, pulmonary function testing, sleep study, pulmonary arteriogram, ventilation-perfusion lung scan (“V/Q scan”), and exercise test. Ultimately, your doctor will require a right heart catheterization to measure the pressures in the lungs.

What are the treatments?

Generally, the treatment is based on the type of PH. The aim is symptom control and treating the underlying disease, if present. There is no cure. “Conventional” therapy includes oxygen,  anticoagulants (“blood thinners”), diuretics (“water pills”), digoxin (heart strengthener), and lifestyle changes/exercise.

Newer medicines include Ventavis (iloprost), Tracleer (bosentan), Letairis (ambrisentan), and Revatio (sildenafil). Your doctor may also suggest lung- or heart-lung transplantation.

What is the prognosis?

Twenty years ago, the untreated median survival was only 2-3 years. Some still quote this number, but newer data suggest prolonged survival, even up to 10 years or more, depending upon the underlying cause.

Where can I get more information?

National Heart Lung and Blood institute
The Merck Manuals
American Family Physician review article
Centers for Disease Control
Pulmonary Hypertension Association