Pulmonary Artery

The pulmonary artery is the short wide vessel connecting the heart to the lungs. Generally arteries are thicker and more flexible then veins, and are responsible for carrying blood away from the heart, whereas veins are responsible for carrying blood to it. This holds true for the pulmonary artery as well, however, the pulmonary artery is unique in that it transports de-oxygenated blood, a function usually accomplished by veins. Its responsibility is to carry de-oxygenated blood from the right ventricle (pumping chamber) of the heart to the lungs. Pulmonary circulation works as follows:

First, oxygen poor blood enters the heart through two large veins and than flows from the right atrium (entrance chamber) into the right ventricle through the open tricuspid (three cusped) valve. When the ventricles are full, the tricuspid valve closes. This prevents blood from flowing backward into the atria (plural for atrium) when the ventricles contract, forcing it through the pulmonary trunk, which divides to form the right and left pulmonary arteries. At the base of this trunk is another valve (pulmonary semilunar valve). This valve opens when the right ventricle contracts. Therefore blood is pushed through this valve, into the pulmonary artery and to the lungs where the blood is oxygenated.

Primary pulmonary hypertension is a condition where blood pressure increases in the pulmonary artery and develops in the following way:

In the lung, there are thousands of capillaries that export oxygen rich blood and import oxygen depleted blood for oxygen renewal. The interior of these capillaries are lined with endothelial cells (cells that prevent blood from leaking out). The outer walls are made up of a muscle type cells that expands and contracts to propel blood through the blood vessel. When Primary Pulmonary Hypertension occurs, the endothelial cells are weakened so that they allow leakage. This leakage in turn causes the muscles type cells surrounding the blood vessels to constrict and inhibit blood flow. The constriction gradually worsens, increasing the pulmonary arterial pressure, and eventually causing a condition called right ventricular hypertrophy.

Typically, the first symptoms of primary pulmonary hypertension are subtle and seemingly innocuous. Patients will initially experience only a general fatigue or tiredness and in most cases imagine that they are simply "out-of-shape." As the condition worsens and pulmonary artery pressure increases, patients experience more acute symptoms such as difficulty in breathing, dizziness and even fainting spells. As time passes, more severe symptoms; swelling in the ankles or legs, bluish discoloration of the lips and skin, and chest pain also develop.

The median survival rate for primary pulmonary hypertension after diagnosis is less than two and a half years. Medical management of PPH consists of anticoagulants, oral vasodilators (which are effective only in 20%-25% of cases), continuous intravenous infusions of prostacyclin, diuretics, and supplemental oxygen.

Because of the subtle development of symptoms, early detection of PPH is unlikely and even when it is suspected, a series of multiple tests to either confirm or dismiss the possibility of this diagnosis are required.

No one is certain as to what causes this disease, but research has shown that there are a number of factors that might be responsible. Some of the possible causes include immune system disease, congenital heart defects, Collagen Vascular Disease, HIV infection, portal hypertension and intravenous drug use or other chemical exposures. The use of certain appetite suppressants as Pondimin (fenfluramine), Redux (dexfenfluramine) and Fen Phen, have been found to greatly increase the risk of developing PPH. An echocardiogram is a good tool for detecting elevated pulmonary artery pressures. However, with some patients, a cardiac catheterization is the only way to confirm the diagnosis.




Learn about New Treatments and Get Research Updates.
Although Pulmonary Hypertension cannot be cured using existing medicine. It can be controlled with new drugs and therapies.

Learn More about your rights to medical care and bill payment assistance>>


Pulmonary Hypertension Treatments

Return to Home Page