Our heart is actually a system of two side-by-side pumps that circulate blood through two parallel loops of circulation. The right side of the heart pumps blood from the veins of the rest of the body to the lungs where it absorbs oxygen and eliminates carbon dioxide, and then returns to the heart.

This oxygen rich blood is then distributed to the rest of the body by the left side of the heart and the other loop.

Definitions:

Hypertension generally refers to elevated pressure in the loop serviced by the left side of the heart and is measured with a blood pressure cuff on our arm.

Pulmonary hypertension refers to increased pressure in the other loop of circulation and must be measured by other means (sensors within the heart or nearby vessels.)

Fen phen is the term used to describe the combination of two drugs, fenfluramine and phentermine.

The use of fen phen has been linked to two significant abnormalities, damage to heart valves (valvular heart disease) and PPH (Primary Pulmonary Hypertension).

Primary Pulmonary Hypertension (PPH), a disease that has been associated with the use of fen phen, involves thickening and constriction of the capillaries in the lungs.

Capillaries are the tiniest blood vessels that exist between arteries (the vessels that cary blood away from the heart to the body and lungs) and veins (the vessels that return blood from the body or lungs to the heart).

Capillary membranes (the walls of capillaries) are where nutrients enter our cells and where oxygen and carbon dioxide are exchanged.

This membrane becomes thickened and the tiny vessels (capillaries) constricted (tightened) as a consequence of exposure to fen phen. This causes an impaired exchange of gases and results in less than adequate supplies of oxygen to our cells and the sensation of difficult breathing. There is no cure for the damage to this membrane or the tiny blood vessels caused by fen phen.

The thickening and constriction seen with PPH (Primary Pulmonary Hypertension) also creates added resistance to blood flow in the lungs and hypertension (elevated pressure) in this loop of circulation. This is referred to as Pulmonary Hypertension.

Symptoms:

The primary symptoms of Primary Pulmonary Hypertension (PPH) are shortness of breath and dizziness. The increased pressure and resistance may cause stress on the heart and lead to enlargement of the heart and eventually an accumulation (build up) of fluid in the liver and other tissues, such as the legs. This is referred to as edema.

Primary Pulmonary Hypertension (PPH) refers to Pulmonary Hypertension that occurs in the absence of underlying heart or lung disease, or other illnesses.

Diagnosis:

This disorder, PPH (Primary Pulmonary Hypertension), can be diagnoses after abnormalities are found using a chest x-ray, high-resolution CAT (Computerized Axial Tomography) scanning, pulmonary function tests and an echocardiogram. An angiogram (right heart catheterization) confirms the diagnosis.