Primary or Unexplained Pulmonary Hypertension

AHA Recommendation

There is extremely wide variability in the severity of pulmonary hypertension among various patients. Evaluating, accurately diagnosing and treating the condition is also very complex. For these reasons, patients with symptoms that suggest pulmonary hypertension require thorough evaluation at a medical center with expertise and experience in pulmonary hypertension.

What is primary pulmonary hypertension (or unexplained pulmonary hypertension)?

Primary or unexplained pulmonary hypertension (PPH) is a rare lung disorder in which the blood pressure in the pulmonary artery rises far above normal levels for no apparent reason. The pulmonary artery is a blood vessel carrying oxygen-poor blood from the right ventricle (one of the heart's pumping chambers) to the lungs. In the lungs, the blood picks up oxygen, then flows to the heart's left side, where the left ventricle pumps it to the rest of the body through the aorta.

Hypertension is a medical term for abnormally high blood pressure. Normal average (also called "mean") pulmonary artery pressure is about 14 mm Hg at rest. In patients with PPH, the average blood pressure in the pulmonary artery is greater than 25 mm Hg at rest and greater than 30 mm Hg during exercise. This abnormally high pressure (pulmonary hypertension) is linked with changes in the small blood vessels in the lungs. These changes increase resistance to blood flowing through the vessels. This increased resistance puts a strain on the right ventricle, which now must work harder than usual to move enough blood through the lungs.

* In the United States, an estimated 500 to 1,000 new cases of primary pulmonary hypertension are diagnosed each year.
* The greatest number is reported in women between ages 20 and 40. However, men and women in all age ranges -- as well as very young children -- can develop PPH.

What causes primary pulmonary hypertension?

We don't know the cause; there may be one or more causes. The low incidence makes learning more about the disease extremely difficult. Studies of PPH also have been difficult because a good animal model of the disease hasn't been available. We think that in most people who develop primary pulmonary hypertension, the blood vessels are very sensitive to certain factors that trigger this disease to develop.

* For example, people with Raynaud's syndrome seem more likely than others to develop PPH.
* In addition, appetite suppressants, cocaine and HIV are some factors believed to trigger the constriction, or narrowing, of the pulmonary artery.

What are the symptoms of primary pulmonary hypertension?

* The first symptom is often fatigue or tiredness. Many patients think that they're simply "out of shape."
* Difficulty in breathing, dizziness and even fainting spells can occur.
* Swelling in the ankles or legs, bluish discoloration of the lips and skin, and chest pain more often occur later in the disease.

One of the great difficulties in treating PPH is that the diagnosis is often delayed due to the slowly progressive and insidious onset of the symptoms.

How is a patient with primary pulmonary hypertension evaluated?

Significant advances in PPH therapy over the past decade have markedly affected the survival and quality of life for people with this disease. The optimal medical and/or surgical treatment for patients with PPH depends upon a thorough evaluation at a medical center with expertise in pulmonary hypertension.

The evaluation includes a right heart cardiac catheterization. In this procedure the doctor places a thin, flexible tube (a catheter) through an artery or vein in the patient's arm, leg or neck, then threads it into the right ventricle and pulmonary artery. This is the only way to measure the pressure in the pulmonary artery and find out what medical therapy is appropriate for a given patient.

What therapy is available for patients with primary pulmonary hypertension?

Doctors can choose from a variety of drugs that help lower blood pressure in the lungs and improve heart performance in many patients. Physicians now know that patients with PPH respond differently to the different medications that dilate or relax blood vessels and that no one drug is consistently effective in all patients. Because individual reactions vary, different drugs have to be tried before chronic or long-term treatment begins. During the course of the disease, the amount and type of medicine also may have to be changed. To find out which medicine works best for a particular patient, doctors evaluate the drugs during cardiac catheterization.

* At present, about one-quarter of patients can be treated with calcium channel-blocking drugs given orally.
* Intravenous prostacyclin is a vasodilator. It helps patients who don't respond to treatment with calcium channel blockers given by mouth. It's continuously delivered by a portable, battery-operated infusion pump. Despite this complexity, prostacyclin improves pulmonary hypertension and permits increased physical activity. This improves the quality of life for patients of all ages. Prostacyclin is sometimes used as a bridge to help patients waiting for a transplant. In other cases it's used for long-term treatment.

Besides oral calcium channel blockers and chronic intravenous prostacyclin, clinical trials are under way to evaluate new drugs to improve the treatment of PPH. Some patients also do well by taking medicines that make the right ventricle's work easier.

* Anticoagulants, for example, can decrease the tendency of the blood to clot, thus permitting the blood to flow more freely.
* Diuretics reduce the amount of fluid in the body, further reducing the amount of work the heart has to do.
* Some patients also require supplemental oxygen delivered through nasal prongs or a mask if breathing becomes difficult. Some need oxygen around the clock.

Transplantation (heart-lung or lung) is reserved for patients who don't respond to medical therapy. The decision whether a patient requires heart-lung transplantation or lung transplantation is made after a thorough evaluation at a lung transplantation center.

What are the long-term prospects for patients with primary pulmonary hypertension?

Despite the complexity of some of the various medical therapies, accurate, early diagnosis and initiation of treatment have saved the lives of many patients with PPH. With optimal medical and/or surgical therapy, patients can often return to a virtually normal lifestyle, including running a household, returning to school and participating in many physical activities.

Most doctors and patients agree that it's very important for both patients and families to be as informed as possible. This lets everyone understand the illness and apply the information to what is happening. In addition to family and close friends, support groups can help PPH patients. More information is available from these organizations:

Pulmonary Hypertension Association (PHA)
850 Sligo Avenue, Suite 800
Silver Spring, MD 20910

PPH Cure Foundation
1826 R Street, NW
Washington, DC 20009-1604
(202) 518-5477

Despite physicians' inability to cure primary pulmonary hypertension, advances in its treatment over the past decade have markedly improved survival and the quality of life for people with primary pulmonary hypertension.

Much of the research and development of treatments have focused on primary pulmonary hypertension. However, these same treatments are now being evaluated in many patients with pulmonary hypertension due to other causes, such as congenital heart disease or disorders such as scleroderma or systemic lupus erythematosus.

See the Related Items box above for links to the Cardiology Patient Page in Circulation, Journal of the American Heart Association:

* Pulmonary Hypertension



Detailed Research

Hypertension Primer, Second Edition

Source:Americanheart