Pulmonary Hypertension

Pulmonary hypertension (PH) happens when the blood pressure in the pulmonary artery rises far above normal levels. The pulmonary artery is the blood vessel carrying oxygen-poor blood from the right ventricle, one of the pumping chambers of the heart, to the lungs. In the lungs, the blood picks up oxygen and then flows to the left side of the heart, where it is pumped by the left ventricle to the rest of the body through the aorta. (Read about "Respiratory System" "The Heart and Cardiovascular System")

Hypertension (Read about "Hypertension: High Blood Pressure") is the medical term for an abnormally high blood pressure. Normal mean pulmonary-artery pressure is approximately 14 mm Hg at rest. According to the National Heart, Lung and Blood Institute (NHLBI), in the PH patient, the mean blood pressure in the pulmonary artery is greater than 25 mm Hg at rest and 30 mm Hg during exercise. This abnormally high pressure (pulmonary hypertension) is associated with changes in the small blood vessels in the lungs, resulting in an increased resistance to blood flowing through the vessels.

This increased resistance, in turn, places a strain on the right ventricle, which now has to work harder than usual against the resistance to move adequate amounts of blood through the lungs. As a result of the increased workload, the right side of the heart can become enlarged, a condition called cor pulmonale, and heart failure can develop. (Read about "Congestive Heart Failure")

Primary and secondary PH

There are two kinds of pulmonary hypertension:

• Primary 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.
• Secondary pulmonary hypertension - When the cause, such as a chronic obstructive pulmonary disease (chronic bronchitis and emphysema) is known, it is called secondary pulmonary hypertension. (Read about "Chronic Obstructive Pulmonary Disease")

PPH remains a diagnosis of exclusion. This means that it is diagnosed only after the doctor finds pulmonary hypertension and excludes or cannot find other reasons for the hypertension, such as COPD, blood clots in the lung (pulmonary thromboemboli) (Read about "Pulmonary Embolism"), or some forms of congenital heart disease. (Read about "Congenital Heart Defects")

In the United States, it has been estimated by NHLBI, that 300 new cases of PPH are diagnosed each year. The American Heart Association puts the estimate higher at between 500 and 1,000. The greatest numbers are reported in women between the ages of 21 and 40. Indeed, at one time the disease was thought to occur among young women almost exclusively; we now know, however, that men and women in all age ranges, from very young children to elderly people, can develop PPH. Apparently it also affects people of all racial and ethnic origins equally, according to NHLBI.

Researchers think that in most people who develop PPH, the blood vessels are particularly sensitive to certain internal or external factors and constrict, or narrow, when exposed to these factors. For example, people with Raynaud's phenomenon (Read about "Raynaud's Phenomenon") seem more likely than others to develop PPH. Raynaud's phenomenon is a condition in which the fingers and toes turn blue when cold because the blood vessels in the fingers and toes are particularly sensitive to cold. Appetite suppressants, cocaine, HIV (Read about "HIV / AIDS"), and pregnancy (Read about "Healthy Pregnancy") are some of the factors that are thought to trigger constriction, or narrowing, in the pulmonary artery.

Symptoms and treatment

The first symptoms of both secondary and primary PH are frequently tiredness, with many patients thinking they tire easily because they are simply out of shape. Difficulty in breathing (dyspnea), dizziness (Read about "Balance Disorders") and even fainting spells (syncope) (Read about "Syncope/Fainting") are also typical early symptoms. Swelling in the ankles or legs (edema) (Read about "Feet, Ankles and Legs"), bluish lips and skin (cyanosis) and chest pain (angina) (Read about "Angina") are among other symptoms of the disease.

Patients with PPH may also complain of a racing pulse; many feel they have trouble getting enough air. Palpitations, a strong throbbing sensation brought on by the increased rate of the heartbeat, can also cause discomfort. (Read about "Arrhythmia")

In cases of secondary pulmonary hypertension, where the cause is known, it is important to try to get the causes under control. However, once you have pulmonary hypertension (especially if you've had it for some time), curing the disease that caused it may not make it go away. You may also need additional treatment.

For both primary and secondary pulmonary hypertension, there was a time when nothing much could be done. However, today doctors can choose from a variety of drugs that help lower blood pressure in the lungs and improve the performance of the heart in many patients. Some patients do well by taking medicines that make the work of the right ventricle easier. Anticoagulants, for example, can decrease the tendency of the blood to clot, thereby permitting blood to flow more freely. Blood vessel dilators may be used. Diuretics can decrease 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. In severely affected cases, a heart-lung, single lung or double lung transplantation may be appropriate. (Read about "Transplants")

Related Information:

    Glossary of Respiratory Terms