Pulmonary hypertension

Pulmonary Hypertension 

Definition

Pulmonary hypertension is a rare lung disorder characterized by increased pressure in the pulmonary artery. The pulmonary artery carries oxygen-poor blood from the lower chamber on the right side of the heart (right ventricle) to the lungs where it picks up oxygen.

Description

Pulmonary hypertension is present when the blood pressure in the circulation of the lungs is measured at greater than 25 mm of mercury (Hg) at rest or 30 mm Hg during exercise. Pulmonary hypertension can be either primary or secondary:

Regardless of whether pulmonary hypertension is primary or secondary, the disorder results in thickening of the pulmonary arteries and narrowing of these blood vessels. In response, the right side of the heart works harder to move the blood through these arteries and it becomes enlarged. Eventually overworking the right side of the heart may lead to right-sided heart failure, resulting in death.

Causes and symptoms

While the cause of primary pulmonary hypertension is uncertain, researchers think that in most people who develop the disease, the blood vessels are sensitive to certain factors that cause them to narrow. Diet suppressants, cocaine, and pregnancy are some of the factors that are thought to trigger constriction or narrowing of the pulmonary artery. In about 6-10% of cases, primary pulmonary hypertension is inherited.

Secondary pulmonary hypertension can be associated with breathing disorders such as emphysema and bronchitis, or diseases such as scleroderma, systemic lupus erythematosus (SLE) or congenital heart disease involving heart valves, and pulmonary thromboembolism.

Symptoms of pulmonary hypertension include shortness of breath with minimal exertion, general fatigue, dizziness, and fainting. Swelling of the ankles, bluish lips and skin, and chest pain are among other symptoms of the disease.

Diagnosis

Pulmonary hypertension is rarely detected during routine physical examinations and, therefore, often progresses to later stages before being diagnosed. In addition to listening to heart sounds with a stethoscope, physicians also use electrocardiogram, pulmonary function tests, perfusion lung scan, and/or right-heart cardiac catheterization to diagnose pulmonary hypertension.

Treatment

The aim of treatment for pulmonary hypertension is to treat the underlying cause, if it is known. For example, thromboendarterectomy is a surgical procedure performed to remove a blood clot on the lung that is causing the pulmonary hypertension. Lung transplants are another surgical treatment.

Some patients are helped by taking medicines that make the work of the heart easier. Anticoagulants, drugs that thin the blood, decrease the tendency of the blood to clot and allow blood to flow more freely. Diuretics decrease the amount of fluid in the body and reduce the amount of work the heart has to do. Calcium channel blockers relax the smooth muscle in the walls of the heart and blood vessels and improve the ability of the heart to pump blood.

One effective medical treatment that dilates blood vessels and seems to help prevent blood clots from forming is epoprostenol (prostacyclin). Prostacyclin is given intravenously to improve survival, exercise duration, and well-being. It is sometimes used as a bridge to help people who are waiting for a lung transplant. In other cases it is used for long-term treatment.

Some people require supplemental oxygen through nasal prongs or a mask if breathing becomes difficult.

Prognosis

Pulmonary hypertension is chronic and incurable with an unpredictable survival rate. Length of survival has been improving, with some patients able to live 15-20 years or longer with the disorder.

Prevention

Since the cause of primary pulmonary hypertension is still unknown, there is no way to prevent or cure this disease. A change in lifestyle may assist patients with daily activities. For example, relaxation exercises help to reduce stress. Good health habits such as a healthy diet, not smoking, and getting plenty of rest should be maintained.

Key terms

Hypertension — The medical term for abnormally high blood pressure.

Perfusion lung scan — A scan that shows the pattern of blood flow in the lungs.

Pulmonary — Having to do with the lungs.

Pulmonary function test — A test that measures how much air the lungs hold and the air flow in and out of the lungs.

Right-heart cardiac catherization — A medical procedure during which a physician threads a catheter into the right side of the heart to measure the blood pressure in the right side of the heart and the pulmonary artery. The right heart's pumping ability can also be evaluated.

Resources

Organizations

American Association for Respiratory Care. 11030 Ables Lane, Dallas, TX 75229. (972) 243-2272. http://www.aarc.org.

Pulmonary Hypertension Association. P.O. Box 24733, Speedway, IN 46224-0733. (800) 748-7274. http://www.phassociation.org.

Other

"Primary Pulmonary Hypertensiton." National Heart, Lung, and Blood Institute. 〈http://www.nhlbi.nih.gov/nhlbi/lung/other/gp/pph.txt〉.

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pulmonary hypertension

n.

Hypertension in the pulmonary circulation; it may be primary or secondary to pulmonary or cardiac disease.