Glossary of Terms

TermDefinition
acute vasodilator testing (challenge). See vasodilator testing.
Angina (pectoris). A type of chest pain. Angina is a sensation of tightness or pressure behind the breastbone (also known as sternum). Angina typically comes on during activity or exertion, and usually lasts for a few minutes. Angina usually indicates the presence of a type of heart disease, caused by narrowing of the arteries (also known as coronary arteries) which feed blood and oxygen to the heart muscle. Patients with PH can also feel angina, which is usually related to the strain on the right ventricle (RV).
angiogram. A type of x-ray picture of blood vessels. An angiogram requires injection of an x-ray dye (also known as contrast material) into blood vessels to make it easier to see abnormalities on the inside, such as a narrowing or blockage. Two types of angiograms are used to look for blood clots in pulmonary arteries in PH patients: CT angiogram (see CT scan) and pulmonary angiogram.
anorexigens (also known as appetite-suppressant medications). A family of medications previously used to suppress appetite and lose weight. For example: aminorex, fenfluramine, dexfenfluramine. Most of these are no longer available. Patients who previously used anorexigen medications for weight loss are at increased risk for PAH.
anti-coagulants (also known as "blood thinners"). These are medications taken to make the blood less likely to clot. Warfarin (Coumadin) tablets are most frequently used. In patients taking warfarin anti-coagulants, the INR must be regularly checked by a blood test, to make sure that the blood is thin enough, but not too thin. Another options is a type of heparin which is either injected into a vein (intravenous = IV) or injected under the skin (subcutaneously = SC).
aortic valve. This is the valve between the left ventricle (LV) and the aorta, the biggest artery in the body. The aortic valve normally prevents blood from leaking backwards from the aorta into the LV. Disease of the aortic valve can cause PH in some patients. The aortic valve can be too tight (also known as aortic stenosis = AS), or the aortic valve can leak blood backwards because it does not close properly (also known as aortic regurgitation = AR, or aortic insufficiency = AI). The aortic valve is assessed by echocardiogram, and sometimes catheterization.
ascites. Swelling of the belly or abdomen, due to the buildup of fluid. Ascites is often seen in patients with liver disease, such as cirrhosis. Ascites can also be seen in patients with severe PH and RV failure.
atrial septal defect (ASD). A type of heart defect present at birth (also known as congenital heart disease). An ASD is an abnormal opening in the wall (also known as septum) between the left atrium (LA) and right atrium (RA), permitting blood to leak between the 2 heart chambers. ASD can be associated with PAH. ASD is usually diagnosed by echocardiogram, and sometimes heart catheterization.
beraprost. A type of PH treatment in the prostanoid family. Beraprost is a medication in tablet form. Beraprost is not currently available. At the present time, there are no plans to further study beraprost or to make it available as a treatment for PH.
bosentan (Tracleer). A type of PH treatment in the family of endothelin receptor antagonists (ERAs). Bosentan is a tablet taken by mouth. ***
BMPR2 (bone morphogenetic protein receptor type II). The first mutant or defective gene ever found which can cause PH. Mutations (DNA errors) in the BMPR2 gene are often the cause of familial PAH (FPAH). In these patients, the gene mutation was transmitted to the patient from her/his parents. BMPR2 mutations have also been found in some patients with idiopathic PAH (IPAH), suggesting that such a gene mutation can also arise spontaneously in individual patients.
calcium channel blockers (CCBs). A family of PH medications in tablet form. CCBs are vasodilators. CCBs open up pulmonary arteries by relaxing the smooth muscle cells in the walls of the pulmonary arteries. Examples include: nifedipine (Procardia XL, Adalat), diltiazem (Cardizem, Tiazac), and amlodipine (Norvasc). CCBs are effective only in a small number (perhaps up to 10 to 15 percent) of patients with idiopathic PAH (IPAH, previously known as PPH).
cardiac catheterization. See pulmonary artery catheterization.
cardiac output (CO). A measure of how much blood the heart pumps every minute, in liters. Expressed in liters per minute (L/min). The normal CO is between 4 and 7 L/min. In patients with PH and RV failure, CO is often reduced. CO is best measured directly during pulmonary artery catheterization. There are non-invasive ways to estimate CO, such as by specific breathing tests, and by echocardiogram.
catheter. A thin, flexible tube usually made of plastic or silicone. A catheter is inserted into a blood vessel to allow direct measurement of blood pressure in the blood vessel, to take a sample of blood, or to inject medication.
chronic thromboembolic PH (CTEPH). Classified as WHO Group IV PH. A type of PH due to recurrent or multiple blood clots in the lungs (also known as pulmonary embolism).
Cialis (tadalafil). A type of PH treatment in the family of phosphodiesterase inhibitors. Cialis is the drug company trade name for tadalafil.
cirrhosis. A serious condition of the liver, usually due to infection with hepatitis viruses (B or C) or heavy alcohol use. Patients with cirrhosis often have higher blood pressure in the portal vein (also known as portal hypertension), which carries blood from the bowels to the liver. Patients with cirrhosis and portal hypertension have a higher risk of pulmonary arterial hypertension (PAH). This is called porto-pulmonary hypertension.
clinical trial. A medical study that evaluates the usefulness, effectiveness, or safety of a new test or treatment in patients. Patients must meet specific eligibility criteria to participate, including a specific diagnosis, and a lack of other specific criteria which may exclude them. A clinical trial is often ˝blindedţ, which means that neither the patient, nor the doctor or the research staff, know which group or arm of the study the patient is in. As well, many clinical trials have a placebo group, which means the patient is not receiving any active medication.
congenital heart disease (CHD). A disease of the heart, in which defects of the heart are present at birth. Some CHD defects allow blood from the left-side of the heart to leak over to the right side of the heart. This leak of blood from the left-side to the right-side of the heart increases the blood flow through the pulmonary arteries and lungs. This high blood flow through the lungs over many years can lead to PAH (CHD-PAH), which is also referred to as Eisenmenger syndrome. Examples of CHD which can lead to PAH include atrial septal defect (ASD) and ventricular septal defect (VSD). CHD is assessed by echocardiogram and often by catheterization.
connective tissue disease (CTD). These are systemic diseases that affect the whole body, especially joints, skin, muscles, and tendons. Most types of CTD can cause PAH, including SLE (lupus), scleroderma (also known as CREST syndrome), and mixed connective tissue disease. CTD is usually diagnosed based on the clinical features and specific blood tests.
CREST syndrome. A type of connective tissue disease (CTD). CREST is better referred to as limited scleroderma.
CT scan (CAT scan). A special type of detailed x-ray image of a part of your body. For example, CT scan of the lungs is used to assess for the possibility of lung disease, such as emphysema or fibrosis of the lungs, which can cause PH. Another type of CT scan is a CT angiogram. CT angiogram requires injection of an x-ray dye (also known as contrast material) into a vein in order to better see blood vessels. CT angiogram is used to diagnose blood clots in the lungs (also known as pulmonary embolism).
coumadin. A drug company trade name for warfarin, an anticoagulant (see above).
diastole. A period of time during the normal cycle of the heartbeat. Diastole is the period of time when your heart relaxes after a beat, and fills with blood again for the next beat. Blood pressure in diastole is called the diastolic blood pressure, and is written as the bottom, lower number in your blood pressure. See systole.
diffusing capacity for carbon monoxide (DLco). The DLco is one part of pulmonary function tests (PFTs). The DLco specifically measures how well the lungs handle gases, like oxygen. In patients with PH, the DLco is often the only abnormal test in the PFTs.
digoxin (Lanoxin). A medication which helps the heart work better. Mainly used in left-sided (left ventricle = LV) heart failure, because digoxin helps the LV work better. It is unproven whether digoxin might help in RV failure.
diuretic. Sometimes called a "water pill." A medication that acts on the kidneys to help them get rid of salt and fluid by increasing the amount of urine. Diuretics help PH patients control their edema (swelling of their feet and ankles). Diuretics can be taken in tablet form, or injected into a vein (intravenously).
dyspnea. A sensation of difficulty breathing or shortness of breath. Dyspnea is a common symptom of PH and other diseases of the heart and lungs.
edema. Swelling of a part of the body by excess salt and fluid. Often seen in the feet and ankles. Edema is a common symptom of PH and other diseases of the heart and lungs. Edema is made worse by taking in too much salt, and is treated by diuretic medication.
Eisenmenger complex or syndrome. A term for the presence of PAH in patients with a birth defect of the heart, or congenital heart disease (CHD). These CHD defects allow blood to leak abnormally from the right-side of the heart (RA or RV) to the left-side of the heart (LA or LV). Eisenmenger syndrome is most commonly due to atrial septal defect (ASD) and ventricular septal defect (VSD).
electrocardiogram (ECG or EKG). A recording of the electrical activity of the heart. Used to diagnose heart disease.
embolism (plural = emboli). The medical term for a blood clot that plugs up a blood vessel. See pulmonary embolism.
emphysema. A term for destruction of lung tissue, which leads to holes in the lungs. Emphysema is often included in the term chronic obstructive pulmonary disease (COPD). Emphysema and COPD are usually due to smoking. Severe emphysema and COPD can cause low blood oxygen levels, which can lead to PH.
endothelin. A chemical in the blood which is made by the endothelium. Endothelin causes narrowing of blood vessels in many ways: as a vasoconstrictor, and endothelin causes cells in the walls of blood vessels (endothelial cells, smooth muscle cells) to grow and multiply abnormally. Patients with PAH have higher amounts of endothelin in their blood and in their lungs.
endothelin receptor antagonists (ERAs). A family of medications in tablet form used to treat PH. In Canada, currently available ERAs include bosentan (Tracleer) and sitaxsentan (Thelin). ERAs block the hormone, endothelin, from attaching to its receptors (ETA and/or ETB receptors) in pulmonary arteries. This prevents the pulmonary arteries from narrowing. ERAs are divided into medications that block both ETA and ETB (such as bosentan), or medications that only block ETA (such as sitaxsentan).
endothelial cells (EC). Endothelial cells are the innermost lining cells of all blood vessels. EC are critical to the normal healthy functions of blood vessels. In normal humans, endothelial cells produce many chemicals that relax blood vessel walls and open up (also known as dilate) the blood vessels. EC also control the growth of smooth muscle cells in the walls of blood vessels. EC also prevent blood clots from forming. In patients with PH, the function and behaviour of EC are disturbed. These abnormal EC are believed to contribute to PH.
endothelium. The innermost lining of all blood vessels, made up of a single layer of endothelial cells.
epoprostenol sodium (Flolan). A type of PH treatment in the prostanoid family. Epoprostenol needs to be administered to a patient as a continuous infusion into a vein (also known as intravenously), through a catheter implanted surgically into a large vein in the neck or upper chest. Epoprostenol treatment uses a delivery system which includes a container (also known as cassette) of epoprostenol drug powder dissolved in liquid, and a pump, worn on a belt-pack or in a back-pack. Epoprostenol may work in PH in several different ways: as a vasodilator, by possibly slowing or stopping the process of scarring (also known as fibrosis) of pulmonary arteries, and by making blood less likely to clot.
familial PAH (FPAH). This term is used when PAH in a patient may be inherited. FPAH should be suspected when a patient with PAH has a history of PAH in at least one other closely related family member (parent, sibling, child), or genetic testing has found a known defective gene (mutation or DNA error) that can cause PAH, such as BMPR2.
fibrosis. A natural process, whereby inflammation leads over time to scarring or the build-up of extra tissue. Fibrosis is made up of collagen fibers, leading to thickening of tissues. Fibrosis of the walls of pulmonary arteries contributes to PH. Fibrosis of the lungs is a cause of PH.
Flolan (epoprostenol). A type of PH treatment in the prostanoid family. Flolan is the drug company trade name for epoprostenol.
Heart failure. A general term for weakness of the heart which leads to poor or inadequate blood flow to the organs of the body. Most commonly, heart failure refers to weakness of the left ventricle (LV) on the left-side of the heart. Patients with PH can develop weakness of the right ventricle (RV), which is known as RV failure. Patients with heart failure are usually tired, weak, have difficulty breathing, have edema, and can feel faint or pass out (also known as syncope).
hemodynamics. Measurements of blood pressure and the flow of blood in the heart or certain blood vessels. For example, pulmonary hemodynamics means the measurement of blood pressure and blood flow in the pulmonary arteries. This usually includes pulmonary artery pressure (PAP), right atrial pressure (RAP), pulmonary capillary wedge pressure (PCWP), and cardiac output (CO). Measurement of pulmonary hemodynamics is critical for (1) diagnosing PH, (2) for measuring the severity of PH, (3) for performing vasodilator testing, and in some patients, (4) assessing whether they are better or worse over time or after receiving a treatment.
hemoptysis. Also known as coughing up blood, or blood in the phlegm. A symptom that may occur in PH, but is commonly due to other lung disease.
human herpesvirus 8 (HHV-8). A type of herpes virus. HHV-8 has been identified as the cause of Kaposi═s sarcoma, a kind of cancer in patients with AIDS. It is controversial whether HHV-8 also causes IPAH.
hypertension. Abnormally high blood pressure. In most patients, hypertension means systemic hypertension, where blood pressure is high in all the systemic arteries of body, BUT blood pressure remains low in the pulmonary arteries. Systemic hypertension is usually diagnosed by measuring blood pressure in the upper arm. In PH patients, the blood pressure is abnormally high specifically in the pulmonary arteries, but blood pressure is normal in all the rest of the systemic arteries of the body. PH needs to be diagnosed by measuring blood pressure in the pulmonary arteries, either with echocardiography or pulmonary artery catheterization.
hypertrophy. A general term for thickening or enlargement of a muscle or an individual cell. The term can be applied specifically to a part of the heart, such as the right ventricle (RV), for example, RV hypertrophy. In other patients, left ventricle (LV) hypertrophy can be a cause of PH, specifically WHO Group II pulmonary venous hypertension.
hypotension. Abnormally low blood pressure. Hypotension is usually due to vasodilator medications, which relax and open up blood vessels. Hypotension can also be due to diuretic medications, which make the body lose more salt and fluid, which can lead to dehydration. A patient with hypotension can feel fatigued, weak, dizzy or lightheaded, sick to their stomach (also known as nausea), warm, flushed, and can faint (also known as syncope).
hypoxemia. Abnormally low level of oxygen in the blood. Hypoxemia is usually a sign of severe lung disease (such as emphysema or fibrosis of the lung) or heart disease (such as congenital heart disease). Hypoxemia causes vasospasm of pulmonary arteries, and can lead to PH. Hypoxemia is usually treated by breathing in additional or supplemental oxygen.
idiopathic. Something that has no obvious cause. For example, idiopathic PAH (IPAH).
idiopathic pulmonary arterial hypertension (IPAH). IPAH is the currently accepted name in the WHO classification system for the older name, primary pulmonary hypertension (PPH). Idiopathic means the cause is unknown. As such, IPAH means PAH without any obvious cause.
iloprost (Ventavis). A type of PH treatment in the prostanoid family. Iloprost is a form of prostacyclin that is available as a treatment for PH in some parts of the world, such as US and Europe. Iloprost is a PH treatment that is breathed in (also known as inhaled), but can also be given through a catheter into a vein (intravenously = IV).
intravenously. Administered by injection directly into a vein.
left ventricle (LV). The lower chamber on the left side of the heart. The LV receives blood from the left atrium (LA; upper chamber of the left heart) and pumps this blood through the aorta, the largest artery in the body, to the rest of the body. Diseases of the LV are a common cause of PH in many patients. Such diseases include weakness or failure of the LV, and LV hypertrophy.
Lupus. See systemic lupus erythematosus (SLE).
mean pulmonary artery pressure (mean PAP). When your heart contracts ("beats") blood pressure rises in your pulmonary arteries (this is your systolic pulmonary artery pressure = SPAP). Blood pressure in the pulmonary arteries falls when your heart relaxes between beats (this is your diastolic pulmonary artery pressure = DPAP). Your "mean PAP" is a continuous average of the pressures in your arteries throughout a complete squeeze/relax cycle. Mean PAP can only be measured by pulmonary artery catheterization. The mean PAP is important, because a diagnosis of PH is defined based on mean PAP greater than or equal to 25 mmHg.
mitral valve. This is the valve between the left atrium (LA) and the left ventricle (LV) on the left side of the heart. The mitral valve normally prevents blood from leaking backwards from the LV into the LA. Disease of the mitral valve can cause PH in some patients. The mitral valve can be too tight (also known as mitral stenosis = MS), or the mitral valve can leak blood backwards because it does not close properly (also known as mitral regurgitation = MR, or mitral insufficiency). The mitral valve is assessed by echocardiogram, and sometimes catheterization.
MRI (magnetic resonance imaging). A type of scan of the body which is done by using a strong magnet and low-energy radio waves. MRI does not use x-rays. MRI is not commonly used in diagnosis of PH, but can be used to assess for lung diseases and certain types of heart disease, such as congenital heart disease (CHD).
Mutant gene (or gene mutation). A defect or error in the DNA sequence or code of a gene. Several mutant genes have been identified as causing familial PAH (FPAH), such as BMPR2.
myocardial infarct (MI). The proper medical term for heart attack. MI means the death of part of the heart muscle because of blockage of the coronary arteries, which normally feed blood and oxygen to the heart. Coronary arteries are narrowed over time due to atherosclerosis (hardening of the arteries) and can get blocked by blood clots.
nitric oxide (NO). A chemical in gas form which is present in the blood and in the lungs, and is made by the endothelium. NO normally contributes to the health of blood vessels. NO relaxes and opens up blood vessels in 2 ways: NO is a vasodilator, which opens up blood vessels by relaxing the smooth muscle in the walls of blood vessels. NO also prevents cells in the walls of blood vessels (endothelial cells, smooth muscle cells) from growing and multiplying abnormally. Patients with PAH have lower amounts of NO in their blood and in their lungs. Since NO is a gas, it can also be breathed in to treat patients with PH. NO is approved and used in the treatment of newborn babies with persistent PH of the newborn (PPHN). NO has also been used experimentally to treat PH in other patients, including patients with IPAH, patients with PH during and after heart surgery, and critically ill patients with PH. Note that NO is not the same gas as nitrous oxide, which is laughing gas used for anesthesia and surgery.
pulmonary arterial hypertension (PAH). A type of PH due specifically to disease and narrowing of the smallest pulmonary arteries. In the new 2003 WHO Venice classification system, all causes of PAH are grouped together in WHO Group I. PAH includes several different types of PAH, including idiopathic PAH (IPAH), familial PAH (FPAH), and PAH associated with other medical conditions, such as connective tissue disease, congenital heart disease, and cirrhosis / portal hypertension (porto-pulmonary hypertension).
palpitations. A sensation of rapid, forceful, or irregular heartbeat.
PAP. See pulmonary artery pressure.
persistent PH of the newborn (PPHN). A type of PH seen in newborn babies. In some newborns, the pulmonary arteries can remain in vasospasm after birth. This causes PH.
perfusion lung scan. This is part of the nuclear ventilation:perfusion (V/Q) lung scan. After a radioactive chemical (also known as radio-tracer) is injected into a vein, your lungs are scanned by a special (gamma) camera to see where the blood has carried the radio-tracer. In normal humans, the blood flow (also known as perfusion) is uniform throughout the lungs. In patients with blood clots (also known as pulmonary embolism) or PH, there are areas of the lungs where perfusion is reduced.
pericardial effusion. Excessive fluid in the pericardial sac around the heart. This is usually detected by Echocardiogram. In patients with PH, the presence of a pericardial effusion is usually a sign of severe PH. In some patients, pericardial effusion can be due to another medical condition, such as connective tissue disease or infection such as tuberculosis.
PH gene. A gene (DNA sequence or code) that causes PH. The first identified PH gene that increases the risk of a patient developing PH is BMPR2. Other PH genes have also been discovered.
phosphodiesterase (PDE-5) inhibitors. A family of medications in tablet form, used to treat erectile sexual dysfunction, and now being used to treat PH. PDE-5 inhibitors work by inhibiting the normal breakdown of cGMP, which allows the body═s own nitric oxide (NO) to work better and longer in the pulmonary arteries. NO and cGMP open up the pulmonary arteries, lowering the pulmonary artery pressure (PAP) and improving blood flow through the pulmonary arteries. PDE-5 inhibitors used in PH include sildenafil (Viagra, Revatio) and tadalafil (Cialis).
Porto-pulmonary hypertension. PH associated with high blood pressure in the liver (also known as portal hypertension) due to severe liver disease, such as cirrhosis.
primary pulmonary hypertension (PPH). An older term for idiopathic PAH.
prostacyclin (prostaglandin-I2 = PGI2). A type of prostanoid chemical that is normally produced in the body by the endothelium in the human body. Prostacyclin normally contributes to the health of blood vessels. Prostacyclin relaxes and opens up blood vessels in many ways: as a vasodilator, by preventing blood clots from forming, and by preventing excessive growth and multiplication of cells in the walls of blood vessels (such as endothelial cells and smooth muscle cells). PH patients don═t make enough prostacyclin. Prostacyclin cannot be used as a treatment, since it is very unstable, only lasting for a few minutes. However, many PH treatments in the prostanoid family are chemically related to prostacyclin (also known as prostacyclin analogues).
prostanoids. A family of chemical molecules related to prostacyclin (also known as prostacyclin analogues). These analogues include: epoprostenol sodium (Flolan), treprostinil sodium (Remodulin), beraprost sodium, and iloprost (Ventavis). The different prostanoid PH medications are not identical, and have different benefits, side-effects, and risks.
pulmonary. Relating to the lungs.
pulmonary angiogram. An angiogram of the pulmonary arteries. This is an invasive test that requires pulmonary artery catheterization, and injection of x-ray dye (also known as contrast material) directly into each of the left and right pulmonary arteries, in order to see blood clots (also known as pulmonary embolism).
pulmonary arteries. The blood vessels that carry blood from the right lower chamber of the heart (right ventricle = RV) to the lungs, where the blood is oxygenated. There is 1 large, main pulmonary artery, a pulmonary artery to each lung (left and right main pulmonary arteries), and many smaller pulmonary artery branches to each lobe and segment of the lungs.
pulmonary artery catheterization. Also known as right-heart catheterization, or Swan-Ganz catheterization. A specialized doctor inserts a thin Swan-Ganz catheter (tube) with a special balloon at the tip into a vein in the neck or groin, and slides it through the heart, and into the pulmonary artery. Through this catheter, pulmonary hemodynamics can be directly measured. This usually includes pulmonary artery pressure (PAP), right atrial pressure (RAP), pulmonary capillary wedge pressure (PCWP), and cardiac output (CO). Measurement of pulmonary hemodynamics is critical for (1) diagnosing PH, (2) for measuring the severity of PH, (3) for performing vasodilator testing, and in some patients, (4) assessing whether they are better or worse over time or after receiving a treatment.
Pulmonary artery pressure (PAP). The blood pressure in the pulmonary arteries. The presence of abnormally high PAP is required to diagnose PH. Normal PAP is 25/10 mmHg, which means systolic PAP is 25 mmHg and diastolic PAP is 10 mmHg, with average (also known as mean) PAP < 25 mmHg. PH is defined by mean PAP higher than or equal to 25 mmHg.
pulmonary artery wedge pressure (PAWP = wedge). During pulmonary artery catheterization, a little balloon at the tip of a catheter is inflated and wedged into a small pulmonary artery, stopping the blood flow in that small pulmonary artery. The blood pressure is then measured in that pulmonary artery, which is the PAWP. The PAWP is similar to the blood pressure in the pulmonary veins and in the left atrium (LA; upper chamber of the left side of the heart). The PAWP can help doctors figure out if there is significant heart disease which could be causing or contributing to PH in a patient.
pulmonary embolism (plural emboli). Also known as blood clots in the pulmonary arteries. In most patients, the blood clots first developed in a vein in the legs (also known as phlebitis) or hips. The clots then break off and traveled to the lungs, landing in the pulmonary arteries. Pulmonary embolism is an important cause of PH in many patients. Pulmonary embolism is usually diagnosed by ventilation:perfusion (V/Q) lung scan, or pulmonary CT scan angiogram.
pulmonary function tests (PFTs). These are breathing tests, which are carried out to find out how much air your lungs can hold, how well air moves in and out, and how well the lungs handle gases, like oxygen. PFTs are important in diagnosing lung disease that can cause PH in some patients. For example, emphysema, pulmonary fibrosis.
pulmonary hypertension (PH). Abnormally high blood pressure in the pulmonary arteries.
pulmonary thromboendarterectomy (PTE). A major surgical operation to remove blood clots and scar from inside the pulmonary arteries. PTE surgery is used to treat patients with PH that is due to pulmonary embolism, or chronic thromboembolic PH (CTEPH).
pulmonary vascular resistance (PVR). This is a measure of the stiffness of the pulmonary arteries, or how difficult it is for the heart to pump blood through the lungs. PVR can only be calculated after measurement of pulmonary hemodynamics, specifically pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), and cardiac output (CO). As such, PVR can only be calculated after pulmonary artery catheterization, and not by echocardiogram.
pulmonary venous hypertension (PVH). Also known as WHO Group II PH. A type of PH due to some types of heart disease, when blood backs up into the lungs. PVH is due to conditions of the left side of the heart, including the left ventricle (LV), left atrium (LA), and left-sided valves, including the mitral valve and aortic valve.
pulmonic valve (pulmonary valve). This is the valve between the right ventricle (RV) and the main pulmonary artery on the right side of the heart. The pulmonic valve normally prevents blood from flowing backwards from the pulmonary artery into the RV. In PH, the pulmonic valve can open up and can leak blood back into the RV, which is known as pulmonic regurgitation (PR) or pulmonic insufficiency (PI).
Raynaud's phenomenon. A symptom felt by patients, characterized by fingers becoming painful and turning different colours (white, blue, and red) during exposure to cold air. Raynaud═s is a sign of vasospasm of the arteries of the hands and fingers. Raynaud's is common in patients with connective tissue disease (CTD; such as scleroderma), and PH.
Remodulin (treprostinil). See treprostinil.
Revatio (sildenafil). A type of PH treatment in the family of phosphodiesterase inhibitors. See sildenafil.
right atrial pressure (RAP). The blood pressure in the right upper chamber or the heart (right atrium = RA). Also referred to as central venous pressure (CVP) or jugular venous pressure (JVP). RAP and CVP need to be measured directly by pulmonary artery catheterization. JVP can be measured by your doctor during physical examination, by looking at the pressure in the great veins in the neck. Higher RAP is a sign of failure of the right ventricle (RV; lower chamber or the right side of the heart).
Right atrium (RA). The upper chamber on the right side of the heart. The RA receives blood back from the rest of the body, and pumps this blood through the tricuspid valve into the right ventricle (RV). In PH patients, the RA is often enlarged (also known as dilated).
right-heart catheterization. See pulmonary artery catheterization. A thin tube with a special tip is inserted into a neck or groin vein and threaded into the pulmonary artery where it measures the pressures.
right ventricle (RV). The lower chamber on the right side of the heart. The RV receives blood from the right atrium (RA; upper chamber of the right heart) and pumps this blood through the pulmonary arteries into the lungs. In PH patients, the muscle of the RV is often thicker and stronger (also known as hypertrophy), the RV is enlarged (also known as dilated).
RV failure. Weakness of the RV, usually due to longstanding or severe PH. This is a type of heart failure, specifically of the right ventricle (RV).
RV hypertrophy. Thickening of the muscle of the walls of the RV. In patients with PH, the RV is under the strain of pumping blood into the pulmonary arteries under higher pressure, and the muscle of the RV often develops hypertrophy over time. RV hypertrophy can lead to RV failure.
Schistosomiasis. A parasitic infection that can cause PH in some parts of the world, especially Africa.
scleroderma. A type of connective tissue disease. Also known as progressive systemic sclerosis (PSS). Scleroderma is divided into either diffuse scleroderma or limited scleroderma (also known as CREST syndrome). Scleroderma is a serious, usually progressive, and sometimes fatal disease. The tissues of the body's organs are thickened and hardened by scarring (also known as fibrosis). Most commonly, the skin is affected. Any other organ can be affected, including the lungs, heart, and kidneys. Many patients with scleroderma will develop PH.
secondary pulmonary hypertension (SPH). An older term for PH that is not primary (idiopathic), but is caused by another illness, such as heart disease, lung disease, or a general medical condition.
Sickle cell disease. A blood disease, which most commonly affects black people. New research suggests that sickle cell disease can often lead to PH.
sildenafil (Revatio or Viagra).
Sitaxsentan (Thelin). A type of PH treatment in the family of endothelin receptor antagonists.
sleep apnea. A condition in which a patient temporarily stops breathing (also known as apnea) for periods of at least 10 seconds while asleep, often repeatedly during the night. Sleep apnea is often associated with snoring, and usually due to obesity. Sleep apnea leads to low levels of oxygen in the blood, and can cause PH. PH in patients with sleep apnea is usually mild.
subcutaneously. Administered by injection under the skin.
syncope. Also known as fainting, or loss of consciousness. A symptom reported by patients with PH and other heart disease. Syncope happens because of decreased blood and oxygen flow to the brain, and is usually temporary. Syncope can be a sign of severe PH.
systemic. Something that refers to or affects the whole body or system. For example: systemic hypertension means abnormally high blood pressure in all the systemic arteries of the body, but not including the lungs.
systemic lupus erythematosus (SLE, Lupus). A type of connective tissue disease. Lupus is a general medical condition that affects many organs of the body. Typical features include skin rash, arthritis, and disease of the heart and lungs. Lupus is associated with PH.
systole. A period of time during the normal cycle of the heartbeat. Systole is the period of time when your heart is actually contracting and squeezing blood out into the arteries. Blood pressure in systole is called the systolic blood pressure, and is written as the top, higher number in your blood pressure. See diastole.
Thelin (sitaxsentan). A type of PH treatment in the family of endothelin receptor antagonists. See sitaxsentan.
Tracleer (bosentan). A type of PH treatment in the family of endothelin receptor antagonist. See ..
treprostinil (Remodulin). A type of PH treatment in the prostanoid family. Treprostinil needs to be administered to a patient as a continuous infusion, in 1 of 2 ways: either (1) intravenously, through a catheter implanted surgically into a large vein in the neck or upper chest, or (2) through a catheter and small needle inserted under the skin (also known as subcutaneously). Treprostinil treatment uses a delivery system which includes a container (also known as syringe) of treprostinil medication dissolved in liquid, and a small pump. Treprostinil may work in PH in several different ways: as a vasodilator, possibly by slowing or stopping the process of scarring (also known as fibrosis) of pulmonary arteries, and by making blood less likely to clot. New inhaled and tablet forms of treprostinil are being studied in PH patients.
Tricuspid regurgitation (TR). Also known as tricuspid insufficiency (TI). This is the leak of blood backwards from the right ventricle (RV) into the right atrium (RA) on the right side of the heart. The speed of TR is measured by echocardiogram, which is then used to calculate RV systolic pressure (RVSP), the blood pressure in the RV, which is similar to the pulmonary artery pressure (PAP). TR can be present in healthy subjects without PH. The speed of TR is normally less than or equal to 2.7 m/sec. In patients with PH, the speed of TR is more than 2.7 m/sec.
Tricuspid valve. This is the valve between the right atrium (RA) and the right ventricle (RV) on the right side of the heart. The tricuspid valve normally prevents blood from leaking backwards from the RV into the RA. In PH, the enlargement of the RV opens up the valve, which can then leak blood back from the RV into the RA, which is known as tricuspid regurgitation (TR) or tricuspid insufficiency (TI).
vasoconstrictor. A medication or chemical that narrows blood vessels by causing spasm (also known as vasospasm) of the smooth muscle in the walls of blood vessels. Narrowing of a blood vessel increases the blood pressure and reduces the flow of blood in that blood vessel. For example, important vasoconstrictor chemicals in PH include endothelin-1 (ET-1), thromboxanes, and serotonin. High blood levels of these chemicals can cause pulmonary artery vasospasm and contribute to PH in some PH patients.
vasodilator. A medication or chemical that relaxes and opens up blood vessels, thereby decreasing blood pressure in those blood vessels. For example, inhaled nitric oxide (NO) gas, intravenous (IV) epoprostenol, and oral calcium channel blockers (CCBs).
vasodilator testing (challenge). A test used to find out if vasospasm is an important cause of PH in certain patients. Vasodilator testing is usually carried out during pulmonary artery catheterization. After measuring pulmonary artery hemodynamics, a vasodilator medication is administered to the patient to try and lower pulmonary artery pressure (PAP) and increase cardiac output (CO). Commonly used vasodilator medications include: inhaled nitric oxide (NO) gas, intravenous epoprostenol, and intravenous adenosine. A good response to vasodilator testing usually means a significant fall in mean PAP, often down close to normal, and an increase in CO. In general, good responses to vasodilator testing are only seen in patients with idiopathic PAH (IPAH). In patients who have a good response to vasodilator testing, many will also respond to long-term treatment with oral calcium channel blocker vasodilator medication over months and possibly years.
vasospasm (= vasoconstriction). Narrowing of a blood vessel due to spasm of the smooth muscle in the wall of the blood vessel. Vasospasm narrows a blood vessel, raising the blood pressure and reducing the blood flow in that blood vessel. Vasospasm of the pulmonary arteries narrows the pulmonary arteries, raising the pulmonary artery pressure (PAP) and causing PH.
ventilation lung scan. This is part of the nuclear ventilation:perfusion (V/Q) lung scan. After you breathe in a radioactive chemical (also known as radio-tracer), your lungs are scanned by a special (gamma) camera to see where the flow of air has carried the radio-tracer. In normal humans, the flow of air (also known as ventilation) is uniform throughout the lungs. In patients with lung disease, such as emphysema or scarring of the lung (fibrosis), there are areas of the lungs where ventilation is reduced.
ventricular septal defect (VSD). A type of heart defect present at birth (also known as congenital heart disease). A VSD is an abnormal opening in the wall (also known as septum) between the left ventricle (LV) and right ventricle (RV), permitting blood to leak between the 2 heart chambers. VSD can be associated with PAH. VSD is usually diagnosed by echocardiogram, and sometimes heart catheterization.
Viagra (sildenafil). A type of PH treatment in the family of phosphodiesterase inhibitors. See sildenafil (Revatio).
warfarin (Coumadin). A medication in tablet form used to treat and prevent blood clots. See anticoagulant.
WHO functional classification of PH. This is a system to classify the severity of PH in patients, based on their symptoms and ability to perform everyday activities. There are four possible classes: I, II, III, and IV. The WHO class of a patient is important, because it helps doctors decide which treatment may be best, the chance of response to treatment, and the chance of PH getting worse or the patient dying from PH. The WHO functional classification is based on an older, NYHA classification for heart disease.