Glossary of Pulmonary Hypertension (PH) Terms
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
A
ACE inhibitors: ACE Inhibitors are Angiotension Converting Enzyme Inhibitors. ACE inhibitors are blood pressure medications that are prescribed for the treatment of systemic hypertension. Some examples of ACE inhibitors include Quinipril, Lisinopril, and Captopril. ACE inhibitors are not part of specific Pulmonary Arterial Hypertension (PAH) therapy; they are used for systemic (“regular”) hypertension and/or left-sided (“regular”) heart failure. There are many drugs in this class available in Australia, with many different trade names.
Acute vasodilator challenge: During a right heart catheterization (RHC), your doctor may administer medications to test whether your pulmonary arteries can dilate (relax and decrease the pulmonary artery blood pressure). A vasodilator challenge is used to help determine which medications may work best to treat your PAH.
Adcirca™: A TGA-approved oral once a day treatment for PAH. Adcirca™ is the brand name for tadalafil, which is the same chemical in the drug Cialis™ (which is used to treat erectile dysfunction). See also phosphodiesterase inhibitor. Cialis is not approved by the TGA for treatment of PAH in Australia.
Aetiology / Etiology (US): The cause of a disease.
Ambrisentan: A TGA-approved oral treatment for PAH. Ambrisentan is the chemical name for Volibris™ (Letairis overseas). See also endothelin receptor antagonist.
Ampoule / Ampule (US): A small, sealed vial commonly made of glass or plastic that contains a drug.
Anaemia / Anemia (US): Known to most people as ‘low blood count’, anaemia is a reduction in the amount of haemoglobin in the body’s red blood cells. Haemoglobin is the chemical in red blood cells that binds with oxygen in the lungs and then transports it to the rest of the body.
Angina: Chest pain or a sensation of pressure in the chest; angina usually results from not enough blood or oxygen getting to the heart muscle. Typically, angina occurs in patients with coronary artery disease, but it can affect patients with many different types of heart disease including pulmonary arterial hypertension, especially when the heart is enlarged.
Angiogram: A type of catheterisation that uses dye injected into the blood vessels to evaluate whether or not the blood vessels are narrowed. An angiogram can be performed of any vessel of the body and can also be performed using CT scanning or MRI without the need to catheterise.
Anticoagulant medications: A group of medications used to thin the blood and block some of the chemicals that make blood clot. These medications can be given by mouth, by subcutaneous injection, or by intravenous injection. Some of the common names of blood thinners include Warfarin (CoumadinTM and MarevanTM) and Heparin. ClexaneTM is the most commonly used subcutaneous heparin in Australia. It is injected once or twice a day. Aspirin is also a blood thinner, but works by making the platelets in the blood less “sticky.” A newer anticoagulant on the market is dabigatran (PradexaTM).
Aorta: Blood vessel that arises from the left ventricle of the heart and delivers blood to the rest of the body. The aorta is the largest blood vessel in the body.
Apnoea / Apnea (US): the stopping of breathing, often during sleep. Obstructive sleep apnoea (OSA) is a disease in which the patient stops breathing for short periods of time during sleep because some part of the airway is blocked. OSA can result in pulmonary hypertension over a long period of time. Treatment for OSA can help PH.
Arginine (L-Arginine): An essential amino acid (amino acids are the protein building blocks of the body). Arginine is thought to help dilate pulmonary arteries through an interaction with nitric oxide (see nitric oxide). It has been thought that patients with PAH may have a deficit of arginine and should take additional arginine as a supplement. The use of L-arginine should always be discussed with a PAH specialist.
Arrhythmia: (Also known as dysrhythmia). An abnormal rhythm of the heart due to a large number of possible causes. Arrhythmias can be fast or slow, and also regular or irregular. See: atrial fibrillation and atrial flutter.
Arterial blood gas – ABG: A blood test that measures the concentrations of oxygen and carbon dioxide in the arterial blood. Usually the blood sample is taken from the radial artery at the wrist.
Associated Pulmonary Arterial Hypertension (APAH): Pulmonary hypertension that occurs alongside another disease or condition, such as scleroderma or congenital heart disease.
Ascites: A build-up of fluid in the abdominal cavity that may be caused by heart, liver or kidney disease. Ascites can cause fullness and heaviness around the waist, causing clothing to be tighter. Can be treated with diuretics (also known as fluid pills) but the exact cause needs to be investigated for and treated.
Atrial fibrillation & atrial flutter: Atrial fibrillation and atrial flutter are very fast abnormal heart rhythms arising from the atria of the heart. they may cause the ventricles to contract very fast and often less efficiently than normal. In fibrillation the atrial rhythm is irregular, so the ventricular rhythm is also irregular; in flutter, the atrial and ventricular rhythms usually are regular. Both of these are common in people with heart and lung disease and can occur in PAH. They may compromise the function of the heart so that it pumps less blood, and this may cause dizziness, light-headedness and occasionally cause a person to faint. People with these arrhythmias will frequently feel palpitations at the time.
Atrial Septal Defect (ASD): A type of congenital heart disease in which the wall between the two entry chambers of the heart (the atria) does not finish forming, leaving a small hole present from birth.
Atrial Septostomy: Surgery which creates a small hole between the two upper chambers (atria) of the heart. Can relieve pressure on the right side of the heart and improve blood flow, but can also decrease oxygen levels in the blood.
Atrium: The heart is a pump that consists of four sections, known as chambers. The atria (plural for atrium) sit above the ventricles and pump blood into the ventricles through heart valves. On the right side of the heart, the right atrium pumps blood through the tricuspid valve into the right ventricle. On the left side, the left atrium pumps blood through the mitral valve into the left ventricle.
B
Balloon angioplasty: A procedure in which a balloon catheter is inflated inside an artery (typically a coronary artery) to increase its diameter.
Beraprost: A prostanoid medication in an oral form. It has been approved in other countries for treatment of PAH. Beraprost is still in clinical trials in the US and is currently not available in Australia.
BiPAP machine: Defined as Bi-level Positive Airway Pressure. It is a small machine for the treatment of obstructive sleep apnoea and other respiratory diseases. Bi-level means that air is delivered under pressure when you breathe in to help assist a bigger inhaled breath, and then a smaller amount of pressure is maintained during exhalation (breathing out) to hold open the airways and stop them from collapsing. BiPAP machines are commonly used at home. See also CPAP.
Bosentan: A TGA-approved oral treatment for PAH. Bosentan is the chemical name for Tracleer™. See also endothelin receptor antagonist.
BMPR2 gene: The “PH gene.” Its full name is bone morphogenetic protein receptor II and some of its mutations have been found in families that have more than one member with pulmonary arterial hypertension (familial PAH) and in some patients with no known family history of the disease (sporadic PAH).
Bradycardia: A slow heartbeat, usually less than 60 beats per minute. Bradycardia is only a problem if it stops the heart from pumping enough blood to the body – for example, causes low blood pressure.
Bronchiolitis Obliterans: A disease of the lung tissue (small bronchial tubes and alveoli), not the blood vessels, usually from an unknown cause. It is important as it may occur as part of chronic rejection after lung transplantation.
C
Calcium channel blockers (CCBs): Blood pressure medicines for systemic hypertension. CCBs have been found to decrease pulmonary artery pressures in a small percentage of PAH patients. CCBs include nifedipine (AdalatTM), diltiazem (CardizemTM), and amlodipine (NorvascTM).
Cardiac catheterization: An important diagnostic test performed to determine if a patient has pulmonary hypertension. Until a right heart catheterization is performed a definitive diagnosis of pulmonary arterial hypertension cannot be made. Right heart catheterization (RHC) is performed by placing a small catheter (tube) into a vein. The tube is advanced along with the blood flow through the right side of the heart into the pulmonary artery. Once the catheter is in the pulmonary artery, measurement of the blood pressure in the pulmonary artery can be made. Left heart catheterization (LHC) is performed in a similar manner except that the catheter is placed into an artery and then passed into the coronary arteries to determine the amount of the disease present. The left side catheterization also measures the functioning of the left side of the heart. Left side catheterizations sometimes use radiopaque dye.
Cardiac output: The total amount of blood the heart pumps per minute. In a healthy person this is 4 to 5 litres per minute; in someone with severe PH it can be decreased to two to three litres or less.
Cardiopulmonary exercise testing (CPET): A way of determining cardiac and pulmonary function by measuring lung gas (oxygen and carbon dioxide) exchange efficiency.
Catheter: Various thin plastic tubes inserted into the body to allow delivery of drugs and fluids. A central line catheter, including Hickman catheters and PICC lines, are inserted through a large vein such as the jugular vein and extend to just above the right heart. In PAH these are typically used to administer intravenous medications, including epoprostenol or treprostinil. Intravenous catheters are short plastic tubes inserted into small veins, usually in the arms. A subcutaneous catheter is a small flexible catheter that is placed under the skin to deliver medications.
Central Sleep Apnoea: A sleep disorder in which the brain’s control of breathing during sleep is abnormal, resulting in periods where breathing may stop for a short time. Patients with CSA may be prescribed a BiPAP ventilator.
Chronic obstructive pulmonary disease (COPD): A chronic disease characterized by difficulty in breathing due to over inflation and destruction of the lung sacs (alveoli) and/or constriction of the tubes leading to the air sacs. Classically caused by smoking or exposure to smoke, may have many other causes as well.
Chronic Thromboembolic Pulmonary Hypertension (CTEPH): A form of pulmonary hypertension which is secondary to chronic (long-time) blood clots in the lungs. This may occur in people who have had pulmonary embolism (PE).
Cirrhosis: Scarring of the liver.
Clinical trials: Medical studies of patients that evaluate the effectiveness of treatments. New drugs for the treatment of PAH have to undergo clinical trials to prove that they are useful. Often these trials involve patients in Australia.
Connective tissue disease (a.k.a. Collagen vascular disease/autoimmune disease): Disorders affecting joints (muscles, bones, tendons, cartilage), and solid organs of the body. Can be the result of an autoimmune (where the immune system harms the body) or genetic process (inherited disease). Types associated with PH include SLE (lupus), scleroderma, rheumatoid arthritis, and mixed connective tissue disease.
Congenital heart disease (CHD): A defect of the heart present at birth. The defects can be simple holes in the heart or much more complex defects.
Cor pulmonale: Enlargement and abnormal function of the right ventricle of the heart which is caused by disease of the lungs (such as COPD). PAH may cause cor pulmonale. Manifests as symptoms of right side heart failure and fluid overload.
Coumadin™: One brand name for warfarin. See warfarin.
COPD: See chronic obstructive pulmonary disease.
CPAP: Defined as Continuous Positive Airway Pressure. It is a small machine for the treatment of obstructive sleep apnea and other respiratory diseases. In obstructive sleep apnea, the airway is “obstructed” due to a patient’s size or changes in the airway anatomy that cause collapse during sleep. The CPAP air pressure helps hold open the airways. See also BiPAP
CREST syndrome: CREST is an acronym for calcinosis, Raynaud’s syndrome, esophageal dysmotility, sclerodactyly, and telangiectasia. CREST is a form of scleroderma that results in calcium deposits in the skin, Raynaud’s phenomenon, esophageal involvement, swollen fingers with tight skin, and skin reddened/discolored by blood vessels. Patients with CREST syndrome are known to have a greater risk for developing pulmonary hypertension.
CT Scan: Previously known as CAT Scan. An x-ray image of the internal organs and tissues taken by narrow x-rays beamed from several angles and run through a computer to form an image with much greater detail than a single x-ray. It is excellent at evaluating solid organs and with the injection of contrast (dye) can provide detailed pictures of the blood vessels and therefore is a common x-ray ordered for evaluation of the heart and lungs in patients with pulmonary hypertension. CT stands for computerised tomography.
Cyanosis: Blue skin – usually the lips, nail beds, face, or tongue – caused by lack of oxygen in the blood.
D
Dabigatrin: A newer anticoagulant that may be taken instead of warfarin. Dabigatrin does not need the frequent blood tests and changes in dosage that make warfarin difficult to take. However, it is much more expensive than warfarin and is more difficult to treat when it causes bleeding.
Deep vein thrombosis (DVT): Formation of blood clots in the veins deep in the body, most typically in the legs or pelvis.
Diastole: The period when the heart is relaxing and filling with blood. Diastolic pressure is the lowest pressure to which blood pressure falls between contractions of the ventricles. See also systole.
Digoxin: A drug that may help the heart muscle contract more strongly, and may also slow the heart rate in some conditions.
Dilate: To relax, expand. Used in the context of blood vessels or the chambers of the heart.
Diluent: A sterile solution used for reconstituting some drugs, such as Flolan powder.
Diuretic: A chemical that helps patients lose water by increasing the amount of urine produced by the kidneys. Sometimes called a "water pill" or “fluid pill.”
Dual ERA: An endothelin receptor antagonist (ERA) that blocks both the ET-A and ET-B endothelin receptors.
Dyspnoea / Dyspnea (US): The sensation of being unable to breathe enough, including feeling short of breath or tight in the chest.
E
Echocardiogram (echo): A non-invasive diagnostic procedure using ultrasound waves to study the heart. It is used to assess disorders of cardiac muscle function or valve function, or other abnormalities such as elevated pulmonary pressure. A graphic record (picture) produced by ultrasonic waves bounced off the heart to show its structures and functioning. The echocardiogram measures the pressures on the right side of the heart, which helps in the diagnosis of pulmonary arterial hypertension.
Oedema / Edema (US): Swelling caused by fluid in the body tissues. It usually occurs in the feet, ankles and legs, but it can occur in the entire body. See also Ascites.
Eisenmenger syndrome: A birth defect that results in a hole in the heart which over the years, because much of the blood flow goes through the lungs that normally would be pumped through the heart, causes high pulmonary artery pressures, which results in PH.
Electrocardiogram (ECG or EKG): A recording of the electrical activity of the heart.
Embolus (plural, emboli): A clump of something (usually a blood clot) or a bubble that has obstructed a blood vessel. Most commonly refers to a blood clot that has formed somewhere else and travelled to the lungs (pulmonary embolus) or to the brain (cerebral embolus, causing a stroke). A thrombus is a fibrinous or platelet blood clot that obstructs a blood vessel at the place where it has formed (such as a thrombus in a coronary artery causing a heart attack). These are all known as blood clots, and can result in PH in some patients who have had pulmonary embolism. See: Chronic Thromboembolic Pulmonary Hypertension
Emphysema: A type of chronic obstructive pulmonary disease (COPD) involving damage to the air sacs in the lungs.
Endothelin: A chemical made by the endothelium (see below). It causes the smooth muscles in the blood vessel’s walls to constrict (tighten up). PAH patients may have overactivity of endothelin.
Endothelin receptor antagonists (ERAs): Bosentan (TracleerTM) and ambrisentan (VolibrisTM in Australia, LetairisTM overseas) are medications that block endothelin from attaching to the endothelium receptors located in the smooth muscle cells of the pulmonary arteries. This prevents the vessels from constricting and helps lower the pulmonary artery pressures.
Endothelin receptors: In order to have an effect, endothelin must connect with an endothelin receptor. There are two main endothelin receptors: ET-A and ET-B. Endothelin receptor antagonists (ERAs) work by blocking one or both of the endothelin receptors. It seems clear that ET-A constricts blood vessels, but the role of ET-B is a matter of debate among researchers.
Endothelium: The one-cell thick lining of the blood vessels. Endothelial cells produce chemical compounds that normally make blood vessel walls relax and dilate. In PAH there is an abnormality in the endothelium which can result in the blood vessels’ inability to relax and dilate. Abnormalities with the endothelium are one cause of elevated pulmonary artery pressures in PAH.
Epidemiology: The study of illness in the population, including how often a disease occurs, frequency in males or females and in different age groups, and many other factors according to the particular disease.
Epoprostenol sodium: A TGA-approved intravenous treatment for PAH. It is delivered intravenously through a central line catheter and with a small pump. Epoprostenol sodium is the chemical name for FlolanTM. See also prostanoid.
F
Familial pulmonary arterial hypertension (FPAH): Previous name for heritable (inherited) pulmonary arterial hypertension. See also heritable pulmonary arterial hypertension.
Fibrin: The insoluble protein end product of blood coagulation, formed from fibrinogen by the action of thrombin in the presence of calcium ions. Fibrin forms the structure of some blood clots.
Fibrosis: Occurs when inflammation or other irritants cause a build-up of fiber-like (connective) tissue (scarring).
Flolan™: A TGA-approved intravenous treatment for PAH. Flolan is the brand name for epoprostenol. See also epoprostenol sodium
Functional classifications for PH: A scale designed to define how unwell a patient with PAH is based on how limited the patient is in his/her daily activities. World Health Organization (WHO) classifications are a modification the New York Heart Association (NYHA) categories for generic heart failure to make them specific to PH patients. The scale is also from one to four. The WHO and NYHA classes are essentially identical, except that if a patient is prone to fainting they automatically go into Class IV under the WHO class. See also NYHA Classification.
G
Gas Exchange: The movement of CO2 (carbon dioxide) from the blood into the lungs and the movement of oxygen from the lungs into the blood stream. This may be diminished over time in people with PAH and others with diseases that cause vascular changes in the lungs, and may be made worse by other illnesses such as pneumonia.
Gene, PH: See BMPR2
General Practitioner (GP): General medical doctor responsible for the day-to-day care of patients.
H
Haemodynamics / Hemodynamics (US): The pressure measurements obtained during the right and left heart catheterization. Typically, in PH, haemodynamics refers to pulmonary blood pressures, cardiac output, and the calculation of pulmonary resistance, which is a combination of both the pulmonary artery pressure and the cardiac output.
Heartbeat: One pump of the heart.
Heritable Pulmonary Arterial Hypertension (HPAH): This term is used when the BMPR2 gene has been identified and there is a family history of pulmonary hypertension.
Hickman catheter: An intravenous line used to administer medication. A Hickman catheter can be left in place for a long period of time. See also catheter.
Human immunodeficiency virus (HIV): An infection that causes part of the immune system to fail and makes the body prone to infectious organisms that typically would not cause serious infections otherwise. Patients with HIV infection can develop PAH at a rate higher than IPAH. The reason is unknown.
Hyperactive: Excessive reaction of tissue.
Hypertension: Abnormally high blood pressure.
Hypotension: Abnormally low blood pressure.
Hypoxaemia / Hypoxemia (US): A low concentration of oxygen in the blood. This condition can make the pulmonary vessels constrict and raise pulmonary arterial (PA) pressure.
Hypoxia: A low concentration of oxygen in the air that is breathed, such as occurs aboard an airliner or high on a mountain.
I
Idiopathic: A medical term that means a disease that has no known underlying cause.
Idiopathic pulmonary arterial hypertension (IPAH): Formerly called primary pulmonary hypertension (PPH). It means pulmonary arterial hypertension where the cause is unknown. It is very rare, with an incidence of approximately two to five per million worldwide.
Iloprost: A TGA-approved inhaled treatment for PAH. Iloprost is the chemical name for VentavisTM. See also prostanoid.
International normalized range (INR): A blood test used to determine how long it takes blood to clot. It is used to determine how much warfarin to prescribe to a patient to help keep the blood thin. Therapeutic INR is usually considered to be 2.0 to 3.5 in most institutions, but the best level for each individual is determined by each person’s doctors.
Intravenous (IV): Literally “inside the vein.” Used to designate fluids or medications administered via a catheter or needle placed into the vein. An intravenous administration is called an infusion.
Ischaemia / Ischemia (US): A localized, temporary reduction in blood flow resulting in tissue/organ damage. In cardiac ischemia, blocked blood flow results in chest pain and can result in a heart attack. Ischemia can happen in any organ/tissue of the body.
K
L
Left heart catheterization: See cardiac catheterization
Lesion: An area of diseased or injured tissue.
Lung volume: The amount of air the lungs hold.
Lupus: See systemic lupus erythematous.
M
Marevan™: One brand name for warfarin. See warfarin.
Mean pulmonary artery pressure (mean PAP): The pulmonary artery pressure (PAP) has a systolic and diastolic component. This is written like a traditional blood pressure measurement. An example is a pulmonary artery pressure 90/40. The mean PAP is a function of the upper (systolic) and lower (diastolic) number. Normal MPAP is 9 – 18 mmHg. See also pulmonary artery pressure.
Magnetic resonance imaging (MRI): An imaging technique that uses a strong magnetic field and low-energy radio waves to image the tissues of the body. MRI images usually have great detail, and can allow doctors to make some diagnoses much easier. In PH, MRI is currently being used to capture better pictures of the heart, heart valves, and the functioning of the heart than seen on echocardiogram.
N
Nebulizer: A machine that can aerosolize medications so that they can be inhaled.
Nitric oxide (NO): A gas which is a potent dilator of blood vessels. (Not the same thing as nitrous oxide, which is “laughing gas”). It is delivered through a face mask or nasal cannulae like oxygen. It has been approved by the FDA for use in newborn babies with persistent pulmonary hypertension. It is being used experimentally for adults with PAH.
Nuclear Medicine testing: Use of radioactive substances in the diagnosis and treatment of disease. A V/Q scan is one example of this.
NYHA Class I - IV: New York Heart Association functional classification which provides an assessment of physical limitations and symptoms of patients with heart disease. This classification system has been modified slightly by the WHO World Symposium on PH to describe pulmonary hypertension patients. See also Functional Classifications for PH.
Briefly stated:
- Class I: Patients with pulmonary hypertension but without resulting limitation of physical activity. Ordinary physical activity does not cause undue dyspnoea or fatigue, chest pain or near syncope.
- Class II: slight limitation of physical activity. They are comfortable at rest. Ordinary physical activity causes undue dyspnoea or fatigue, chest pain or near syncope.
- Class III: marked limitation of physical activity. They are comfortable at rest. Less than ordinary physical activity causes undue dyspnoea or fatigue, chest pain or near syncope.
- Class IV: inability to carry out any physical activity without symptoms. These patients manifest signs of right heart failure. Dyspnoea and/or fatigue may even be present at rest. Discomfort is increased by any physical activity.
More information:
- See: http://www.abouthf.org/questions_stages.htm
- See: WHO classification as well.
Obstructive Sleep Apnoea (OSA): A sleep disorder in which fatty tissue in the upper body blocks the flow of air into the lungs during sleep. People with OSA may be prescribed a CPAP or BiPAP ventilator.
Oximeter / pulse oximeter: A device to measure the saturation of oxygen in the blood by measuring the colour of skin (usually finger nail bed or earlobe). Normal saturation is around 97-100 percent. In patients with lung disease it is generally desirable to be above 90 percent “saturated. Some patients with congenital heart disease live with saturations less than 90 percent, since oxygen supplementation does not usually increase their saturation. See also pulse oximeter.
Oxygen (O2): Oxygen, or O2, is given as inhaled gas to patients when the oxygen level in the bloodstream is low. Low oxygen occurs with lung disease (PAH, COPD, pneumonia, etc.) and when there is low oxygen content in the air such as at high altitude.
Oxygen saturation (or sat): A measurement of how much oxygen concentration is in the blood. Also called “O2 sat.”
P
Palpitation: A sensation of rapid, skipped, or pounding heartbeats. Sometimes more noticeable when sitting quietly or lying in bed at night. Palpitations are common in everyone but may indicate heart disease if persistent and very frequent.
Pathogenesis: Describing the origin and development of a disease.
Persistent pulmonary hypertension of the newborn (PPHN): Occurs when a newborn’s arteries to the lungs remain constricted after delivery, cutting down on blood flow to the lungs and resulting in PH. PPHN is treated with inhaled nitric oxide.
Phosphodiesterase (PDE-5) inhibitors: A type of medication that inhibits (blocks) the enzyme phosphodiesterase (PDE-5). PDE-5 breaks down a molecule called cyclic GMP (cGMP). cGMP is the “messenger” of nitric oxide (NO) which causes vasodilatation (opening up of the blood vessels). Blocking the breakdown of cGMP then leads to more NO effects. These medications, including sildenafil (Viagra) and tadalafil (Cialis), were first used to treat erectile dysfunction. Brand name drugs Revatio (sildenafil) and Adcirca (tadalafil) are the only PDE-5 medications specifically approved for the treatment of PAH.
Portopulmonary hypertension: PH that develops due to high blood pressure in the liver. Usually caused by cirrhosis (scarring).
PradexaTM: A newer anticoagulant containing dabigatran. Dabigatran is an alternative to warfarin and has the advantage of not requiring frequent blood testing. The disadvantages are that it is much more expensive than warfarin and may be more difficult to reverse when bleeding occurs.
Primary pulmonary hypertension: Old classification for PH without a known cause. See also idiopathic pulmonary arterial hypertension
Prostacyclin: A substance made by the body that helps regulate pulmonary blood vessel “tone” by dilating the blood vessels. It is particularly active in the blood vessels of the lungs and is found to be in very low amounts in patients with PAH. This has led to the development of man-made prostacyclin (such as epoprostenol). The study of epoprostenol infusion for PH in the 1980s and early 1990s proved helpful to PH patients and led to its approval in 1995 in the US. In addition to being a vasodilator, prostacyclin may inhibit the growth and thickening of the pulmonary vessel walls, and make platelets less “sticky,” both helpful in the treatment of PAH. The name prostacyclin comes from the prostate gland because prostaglandin was first isolated from seminal fluid and was thought to have been made by the prostate.
Prostanoids: Prostanoids are a family of chemicals normally made in the body that help regulate blood vessel tone (see above). Members of the prostanoid family of drugs are chemically very similar to one another. Prostacyclin is a type of prostanoid. Currently available prostanoids include epoprostenol sodium (Flolan), treprostenol sodium (Remodulin), iloprost (Ventavis), and inhaled treprostinil (Tyvaso). These prostacyclin analogs help PH patients by dilating blood vessels, reducing clotting, slowing down the growth of smooth muscle cells, and improving cardiac output. Although they are all in the same class of drugs, chemically they are not identical, and their toxicity, side effects, and effectiveness may differ.
Pulmonary: Relating to the lungs.
Pulmonary angiogram: An x-ray of the blood vessels injected with dye which highlights any blockages. Usually performed using either CT or MRI.
Pulmonary artery (PA): The blood vessel carrying blood from the right ventricle of the heart to the lungs, where the blood is oxygenated. It begins as the main pulmonary artery, then branches into the right and left pulmonary arteries feeding the right and left lungs respectively, then continues to branch into smaller and smaller blood vessels, eventually becoming capillaries that exchange oxygen (O2) and carbon dioxide (CO2)within the alveoli (air sacs). A measure of the blood pressure in the pulmonary artery. See also mean pulmonary artery pressure.
Pulmonary arterial hypertension (PAH): Pulmonary arterial hypertension (PAH) is more specific than the general term “pulmonary hypertension” (see pulmonary hypertension below). PAH is high blood pressure in the pulmonary arteries from disease of the medium- and small-sized vessels of the lung, causing them to narrow and impede blood flow. The classification of PAH is determined by the World Health Organisation. The following link provides a summary of this classification.
Pulmonary artery wedge pressure: A measurement obtained during right heart catheterization (see also cardiac catheterization). A balloon on the tip of the right heart catheter is inflated (wedged) in the pulmonary artery where it can also estimate pulmonary vein pressures.
Pulmonary function tests (PFTs): A series of tests to find out how much air the lungs can hold, how well the lungs move air in and out, and how well they exchange oxygen. The tests can help diagnose some conditions that cause PH.
Pulmonary hypertension (PH): Pulmonary hypertension is a general term used to describe high pressure in the pulmonary arteries from any cause.
Pulmonary hypertension gene: See BMPR2. Others may yet be discovered.
Pulmonary Thromboendarterectomy (PTE): A surgical procedure to remove a blood clot (or clots) in the pulmonary arteries in the lungs. May be an important treatment for Chronic Thromboembolic Pulmonary Hypertension.
Pulmonary vascular resistance (PVR): A measure of how difficult it is for the heart to pump blood through the lungs. PVR is a calculation obtained during cardiac catheterization. The PVR is often very high in patients with pulmonary hypertension.
Pulmonary vein: The blood vessel returning oxygenated blood from the lungs back to the left side of the heart.
Pulmonary venous hypertension: A condition in which blood flow through the left side of the heart is decreased, causing a backup of blood in the pulmonary veins and therefore causing higher pulmonary vein and pulmonary artery pressure. This cause of this disease is not in the pulmonary arteries, and therefore is not usually treated with drugs designed to treat PAH. Pulmonary venous hypertension can be confused with PAH, especially early in investigation.
Pulse Oximeter/Oximeter: See oximeter.
R
Raynaud's phenomenon: When fingers get blue and cold easily, and sometimes painful because of a vascular disorder. Persons with PAH can also have Raynaud’s phenomenon. It is also associated with autoimmune disorders.
Remodulin™: A TGA-approved intravenous or subcutaneous treatment for PAH. Remodulin is the brand name for the intravenous and subcutaneous forms of treprostinil. See also treprostinil.
Revatio™: A TGA-approved oral treatment for PAH. Revatio is the brand name for sildenafil. See also sildenafil.
Right atrial pressure: The pressure in the right atrium of the heart. Usually the right atrial pressure is less than 5 mmHg. Elevated right atrial pressure is a sign of right-heart failure and / or too much fluid in the body.
Right heart catheterization: See also cardiac catheterization
Right ventricle: The chamber of the heart that pumps un-oxygenated blood through the pulmonary arteries into the lungs. In PAH patients, this chamber is often enlarged, its walls are thickened, and its ability to pump blood is reduced.
S
Sarcoidosis: A disease in which swelling (inflammation) occurs in the lymph nodes, lungs, liver, eyes, skin, or other tissues. In the lungs it can form granulomas (small areas of inflammation due to tissue injury) and fibrosis (scarring) which can cause PH.
Scleroderma: A progressive disease in which the body's tissues slowly accumulate excessive connective tissue. In some persons, only the skin is affected; in others, even the internal organs harden, including the lungs. It is not known what causes it but there is a genetic component, and it is more common in women than in men. Scleroderma is a common cause of both PH and sometimes PAH.
Secondary pulmonary hypertension (SPH): The old classification for PH that occurred due to another disease or condition. See also associated pulmonary arterial hypertension
Selective ERA: An endothelin receptor antagonist (ERA) that blocks only the ET-A endothelin receptor. ET-A plays a significant role in the constricting of blood vessels.
Shortness of Breath (SOB): Short of Breath. See Dyspnoea.
Sildenafil : An TGA-approved oral treatment for PAH. Sildenafil is the chemical name for Revatio™ and Viagra™. See also phosphodiesterase inhibitor
Six-minute walk test (6MWT)/six-minute walk distance (6MWD): A measurement of how far a person can walk in six minutes, including their oxygenation and how short of breath they are at completion. Six minute walk tests are often used as a measure of whether PAH is improving or worsening.
Sleep apnoea: A disorder in which pauses in breathing occur during sleep.
Sleep Mask: A device used with either BiPAP or CPAP to deliver pressure through the nose or the mouth.
Subcutaneous: Situated under the skin.
Syncope: Fainting because of a temporary insufficiency of blood to the brain.
Systemic: Something that affects the body generally rather than just affecting one of the body’s parts.
Systemic Lupus Erythematosus (SLE): A progressive autoimmune inflammatory disease of connective tissue. Its cause is unknown. A skin rash may be present that spreads across the face in a butterfly wing pattern. The disease often involves the heart and lungs. It is associated with PAH (patients with SLE are much more likely to get PAH than people in the general population). Also known simply as Lupus.
Systole: The period when the heart is contracting and squeezing blood out. Systolic Pressure is the top or higher number in blood pressure measurement. See also diastole
T
Tadalafil: A TGA-approved oral treatment for PAH. Tadalafil is the chemical name for Adcirca™ and Cialis™. See also phosphodiesterase inhibitor.
Teratogenic: Causing developmental malformations when a pregnant women is exposed. Best known example is thalidomide. Some drugs used in the treatment of PAH may be teratogenic, so patients must always consult their specialist before planning pregnancy (including male patients).
Thoracentesis: A procedure in which pleural effusion (fluid that has collected abnormally in the space around the lungs) is removed with a needle and syringe or a catheter, so it can be analysed, and also to relieve shortness of breath caused by lung tissue compression.
Therapeutic Goods Authority (TGA): Federal government authority that approves the distribution and use of all medical substances and equipment in Australia.
Tracleer™: A TGA-approved oral treatment of PAH. Tracleer™ is the brand name for Bosentan. See also Bosentan
Treprostinil: A TGA-approved intravenous, subcutaneous and inhaled treatment of PAH. Treprostinil is the chemical name for Remodulin™ (intravenous and subcutaneous) and Tyvaso™ (inhaled). See also prostanoid
Tyvaso™: A TGA-approved inhaled treatment for PAH. Tyvaso is the brand name for the inhaled form of treprostinil. See also treprostinil.
V
Vasoconstrictor: Anything that narrows the blood vessels, thereby increasing blood pressure. The body maintains a balance in blood vessels between constriction (closing) and dilation (opening) so that blood flow through the blood vessels can be regulated. Blood vessel tone has to do with how much constriction and dilation is occuring at a given time. Constriction of a blood vessel is called vasoconstriction, and dilation of a blood vessel is called vasodilation or vasodilatation.
Vasodilator: Anything that relaxes and widens blood vessels, thereby decreasing blood pressure.
Veletri™: A TGA-approved intravenous treatment for PAH. Veletri is the brand name for a form of epoprostenol that is stable at room temperature (meaning it can be used without ice packs for 24 hours). See also prostanoid.
Ventavis™: A TGA-approved inhaled treatment for PAH. Ventavis is the brand name for iloprost. See also iloprost.
Ventricle: One of the two pumping chambers of the heart. The right ventricle receives oxygen-poor blood from the right atrium and pumps through the lungs, after which it is pumped by the left ventricle through the rest of the body.
Ventricular Septal Defect (VSD): A hole in the ventricular septum, the wall that separates the right and left ventricles of the heart; the hole allows blood to communicate between these two chambers. It may be present from birth (congenital) or develop later due to heart disease.
Viagra™: A TGA-approved oral treatment for erectile dysfunction. Viagra is the brand name for sildenafil (the same chemical used in the PAH drug, Revatio™). See also sildenafil.
VO2: A measure of the amount of oxygen (O2) that the body takes in (and thus uses). Doctors measure peak VO2 during exercise; the higher the number, the better the ability of the heart and lungs to deliver oxygen to the body. It is measured in millilitres of oxygen per minute.
Volibris™: An TGA-approved oral treatment for PAH. Volibris (Letairis overseas) is the brand name for ambrisentan. See also ambrisentan.
Ventilation/perfusion, or V/Q scan: This is a nuclear medicine scan mainly used when attempting to diagnose pulmonary embolism. There is a ventilation scan (V) showing air flow in the lungs and a perfusion scan (Q) showing blood flow in the lungs. A V/Q scan doesn’t help diagnose pulmonary hypertension.
W
Warfarin: Also known as Coumadin™ or Marevan™. It is a blood thinner prescribed for patients that are at risk of developing blood clots (see CTEPH). It is also given to patients with pulmonary hypertension, as there is some evidence that the blood vessels with high pulmonary pressures can be prone to microscopic clots. Warfarin can help prevent further clots and prevent existing clots from getting bigger. Coumadin™ and Marevan™ are the two brand names in Australian for warfarin. The same dose of Coumadin and Marevan are not equivalent, and patients taking one brand you must not change to the other brand. See also anticoagulant medications.
Compiled By
Dr Richard Whitaker MBBS, FACEM, GC ClinEd (UNSW) and Annie Whitaker – 2012