Glossary

Antiphospholipid antibodies

Autoimmune antibodies including anticardiolipin antibodies and lupus anticoagulant, produced against phospholipid in cell membranes. The production of these antibodies may lead to formation of blood clots, pregnancy loss or pregnancy-related complications, and is known as antiphospholipid syndrome (APS).

Apixaban

An oral, direct Factor Xa inhibitor (Eliquis®) developed by Pfizer and Bristol Myers-Squibb, which has been investigated in phase III clinical trials for VTE prevention in patients undergoing major orthopaedic surgery, VTE prevention in medically ill patients, VTE treatment, stroke prevention in atrial fibrillation, and secondary prevention of acute coronary events. Apixaban has received regulatory approval for VTE prevention in patients undergoing hip or knee replacement surgery and for the prevention of stroke and systemic embolism in adult patients with non-valvular atrial fibrillation.

Atherosclerosis

A condition in which the arterial wall thickens as a result of the accumulation of fatty deposits including cholesterol. It is a chronic inflammatory response in the arterial walls, promoted by low-density lipoproteins and caused largely by the accumulation of white blood cells, macrophages and vascular smooth muscle cells.

Atherosclerotic plaque

A thickening of the arterial wall, which may consist of cholesterol, calcium, cellular debris and vascular smooth muscle cells. The plaque may grow and lead to narrowing of the artery, causing serious problems, including heart attack, stroke or even death.

Atrial fibrillation

The most common type of cardiac arrhythmia (irregular heartbeat) associated with an increased risk of stroke, congestive heart failure and mortality.

Biomarker

A biomarker (biological marker) is an indicator of a biological state that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes or pharmacological responses to a therapeutic intervention. Examples of biomarkers associated with VTE include D-dimer and soluble P-selectin.

Bivalirudin

A parenteral reversible direct inhibitor of thrombin that inhibits both circulating and clot-bound thrombin, while also inhibiting thrombin-mediated platelet activation and aggregation.

Cardiac troponins

A complex of three myocardial regulatory proteins – troponin I, C and T, which are found in varying amounts in skeletal and cardiac muscle. Together, these regulate the calcium-modulated interaction of actin and myosin. Troponin levels are sensitive markers of myocardial injury and various other heart disorders.

Cardioembolic stroke

Cardioembolic stroke is caused by blood clots that originate in the heart and is the most severe form of ischaemic stroke, which accounts for a substantial proportion of all cerebral infarctions.

Cardiogenic shock

A physiological state in which inadequate tissue perfusion results in cardiac dysfunction, most often systolic.

Cardiopulmonary reserve

The interdependence of the heart, lungs and oxygen-carrying capacity of any given patient.

Cerebrovascular disease

A group of diseases of the blood vessels supplying the brain, frequently caused by hypertension. Such diseases can include stroke, haemorrhagic stroke, ischaemia or other blood vessel dysfunctions.

CHADS2

An index to determine the risk of stroke in patients with atrial fibrillation. One point each is assigned for the presence of: Congestive heart failure, Hypertension, Age ≥75 years and Diabetes mellitus; and two points for a history of Stroke or transient ischaemic attack.

CHA2DS2-VASc

A risk factor-based approach defining ‘major’ and ‘clinically relevant non-major’ risk factors for stroke in patients with atrial fibrillation. The CHA2DS2-VASc scheme assigns points for each of the following factors: Congestive heart failure/left ventricular dysfunction (1 point), Hypertension (1 point), Age ≥75 years [doubled] (2 points), Diabetes (1 point), Stroke [doubled] (2 points) – Vascular disease (1 point), Age 65–74 years (1 point), and Sex category [female] (1 point).

Chronic thromboembolic pulmonary hypertension

A rare disease that results from obstruction of the major pulmonary arteries. Pulmonary emboli that have become incorporated into the pulmonary artery wall eventually cause an increase in pulmonary vascular resistance.

Computed tomography

Also known as CAT scan. A radiographic technique that uses a computer to assimilate multiple X-ray images into a two-dimensional cross-sectional image. Types of computed tomography include:
Helical/spiral CT – a computed tomography technology involving movement in a helical pattern for the purpose of increasing resolution. Most modern hospitals use spiral CT scanners.
CT pulmonary angiography – highly sensitive and specific diagnostic test, involving injection of intravenous contrast medium to visualize the pulmonary arteries.
CT venography – contrast-enhanced axial CT images. Also known as ‘indirect CT venography’, it is performed in conjunction with CT pulmonary angiography and not as a standalone examination.

Coronary artery bypass graft (CABG) or coronary artery bypass surgery

A surgical procedure used to treat coronary heart disease, which involves taking a blood vessel from another part of the body, usually the chest or leg, and attaching it to the coronary artery above and below the narrowed area or blockage. This new blood vessel (graft) diverts the flow of blood around the part of the coronary artery that is narrowed or blocked.

Coronary heart disease

Coronary Heart Disease is the narrowing or blockage of the coronary arteries, usually caused by atherosclerosis. This can result in restriction of the blood flow to the heart muscle by physically clogging the artery or by causing abnormal artery tone and function. Such diminished blood flow may lead to angina, myocardial infarction, arrhythmia or heart failure.

Coronary reperfusion

Restoration of blood supply to ischaemic heart tissue, using methods such as chemical dissolution of an occluding thrombus, administration of vasodilator drugs, angioplasty, catheterization or artery bypass graft surgery.

Coronary revascularization

Restoration of blood supply to the heart, commonly performed using percutaneous coronary intervention or coronary artery bypass grafting procedures.

Cytokines

A family of diverse cell-signalling proteins secreted by many cells, which are used extensively in intercellular communication. Cytokines can be classified as proteins, peptides or glycoproteins.

Dabigatran

An oral direct thrombin inhibitor (Pradaxa®) developed by Boehringer Ingelheim, which has been investigated in phase III clinical trials for VTE prevention in patients undergoing major orthopaedic surgery, VTE treatment, stroke prevention in atrial fibrillation and secondary prevention of acute coronary events. Dabigatran has received regulatory approval for VTE prevention in patients undergoing hip or knee replacement surgery and for the prevention of stroke and systemic embolism in adult patients with non-valvular atrial fibrillation.

D-dimer

A marker of endogenous fibrinolysis that can be routinely used as a diagnostic aid to exclude deep vein thrombosis or pulmonary embolism.

Direct Factor Xa inhibitors

A class of anticoagulant drugs that act directly on activated Factor X (Factor Xa) in the coagulation cascade and do not require antithrombin as a mediator. Examples include apixaban, rivaroxaban, betrixaban and edoxaban.

Direct thrombin inhibitors

A class of anticoagulant drugs that act directly on thrombin in the coagulation cascade. Examples include hirudin, bivalirudin, argatroban, melagatran and dabigatran.

Dyslipidaemia

An abnormal concentration of lipids or lipoproteins in the blood.

Dyspnoea

Difficult or laboured breathing; shortness of breath.

Echocardiography

The process of using an echocardiogram to record depolarization and repolarization voltages of the cardiac muscle, via detection of electrical activity by electrodes applied to the skin. Used to detect abnormal heart rhythms or cardiac muscle damage.

Edoxaban

An oral, direct Factor Xa inhibitor (Lixiana®) developed by Daiichi Sankyo. It has been investigated in phase III trials of prevention of VTE after major orthopaedic surgery (hip replacement, knee replacement and hip fracture). Other phase III trials are ongoing for VTE treatment and for the prevention of stroke in patients with atrial fibrillation. Edoxaban is approved in Japan for the prevention of VTE in patients undergoing major orthopaedic surgery.

Embolus

Any detached, travelling intravascular mass carried by the circulation, which is capable of blocking arterial capillary beds at a site distant from its point of origin. If a thrombus breaks loose from its original site, it becomes a thromboembolus; if it is not broken down during transit, may cause an embolism in another artery or vein.

Endophlebectomy

A procedure that involves unblocking venous segments that are narrowed by intraluminal scars and masses to improve circulation.

Factor V Leiden

A variant of human Factor V, associated with hypercoagulability disorder, which is relatively common in some populations. Carriers of Factor V Leiden have a modest risk of developing VTE.

Fibrinolysis

A process whereby thrombi are broken down by the enzyme plasmin. Primary fibrinolysis is a normal process of the body; whereas secondary fibrinolysis is the breakdown of clots due to a medicine, a medical disorder or some other cause.

Haemoptysis

The coughing up of blood originating from the respiratory tract below the level of the larynx.

Haemorheology

The study of flow properties of blood and its elements (plasma and formed elements, including red blood cells, white blood cells and platelets).

Heart failure

A condition that may occur when cardiac output is insufficient to meet the needs of the body and lungs. It is commonly referred to as congestive heart failure. The symptoms of heart failure usually develop quickly (acute heart failure), but they can also develop gradually, over time (chronic heart failure).

Hypotension

Abnormally low blood pressure, especially in the arteries of the systemic circulation.

Idiopathic

Of unknown cause. Any disease that is of uncertain or unknown origin may be termed idiopathic (alternatively may be described as unprovoked).

Intermittent pneumatic compression

A therapeutic technique designed to improve venous circulation in the limbs of patients at risk of VTE. Used in medical devices such as air pumps, inflatable auxiliary sleeves, gloves or boots.

Intracerebral haemorrhage

Rupture of a blood vessel within the brain, in areas such as the basal ganglia, cerebellum, brainstem or cortex.

Laparoscopy

A minimally invasive surgical procedure that enables the surgeon or gynaecologist to directly view the organs of the abdomen and pelvis.

Left ventricular ejection fraction

The volume of blood pumped out of the left ventricle with each heartbeat or cardiac cycle, via the aortic valve into the systemic circulation.

Left ventricular systolic function

A measure of the functionality of the left ventricle to pump blood.

Magnetic resonance imaging

An imaging technique that uses the magnetic properties of hydrogen and its interaction with both a large external magnetic field and radio waves to produce highly detailed images of the human body (alternatively known as nuclear magnetic resonance, or NMR, imaging).

Percutaneous coronary intervention

A procedure that involves non-surgical widening of the diseased coronary artery, using a balloon catheter to dilate the artery from within.

Peripheral arterial disease

A common but often overlooked condition in which a build-up of fatty deposits (atheroma) in the arteries restricts the blood supply to leg muscles. It is also known as peripheral vascular disease.

Phlebotonic

Having a toning effect on the veins. A term used to describe a class of drugs derived from plant extracts commonly used to treat chronic venous insufficiency. They are powerful antioxidants that work by stimulating release of chemicals within the vein walls to strengthen the circulation and reduce inflammation and fluid collection within the tissues.

Post-partum

The period after childbirth – from 1 hour after delivery of the placenta through the first 6 weeks of an infant’s life.

P-selectin

A cell adhesion molecule expressed on platelets and endothelial cells, which can be used as a biomarker of thrombogenesis.

Prasugrel

A platelet inhibitor (Effient®) developed by Daiichi Sankyo. Prasugrel, when co-administered with acetylsalicylic acid, has received regulatory approval for the prevention of atherothrombotic events in patients with acute coronary syndrome (i.e. unstable angina, non-ST segment elevation myocardial infarction [UA/NSTEMI] or ST segment elevation myocardial infarction [STEMI]) undergoing primary or delayed percutaneous coronary intervention.

Pulmonary arterial hypertension

A progressive disease characterized by an increase of blood pressure in the pulmonary artery, leading to symptoms including shortness of breath, dizziness and fainting.

Pulmonary embolism

A potentially life-threatening complication of VTE, caused by an embolus in the pulmonary bed. Massive (high-risk) pulmonary embolism is usually defined by the presence of clinically overt right ventricular failure, resulting in haemodynamic compromise.

Pulmonary endarterectomy

An operation that is performed to remove thrombi from the pulmonary arteries.

Recurrent event

An event that occurs more than once in a patient over time. Examples may include a recurrent VTE (which could present as deep vein thrombosis or pulmonary embolism) or a recurrent acute coronary syndrome event.

Risk factor

Any attribute, characteristic or exposure of an individual that increases the likelihood of developing a disease or injury. Transient risk factors are those that are temporary, such as major surgery, hospitalization and long-distance travel. Examples of persistent (permanent) risk factors include cancer or antiphospholipid syndrome.

Rivaroxaban

An oral, direct Factor Xa inhibitor (Xarelto®) developed by Bayer HealthCare and Janssen Research and Development, LLC. Rivaroxaban has undergone extensive investigation in phase III trials for VTE prevention in patients undergoing major orthopaedic surgery, VTE prevention in medically ill patients, VTE treatment, stroke prevention in atrial fibrillation and the secondary prevention of acute coronary events. Rivaroxaban has received regulatory approval for the prevention of VTE in patients undergoing hip or knee replacement surgery, the treatment and secondary prevention of DVT and PE, and the prevention of stroke and systemic embolism in adult patients with non-valvular atrial fibrillation.

Sinus rhythm

The normal regular rhythm of the heart. This is set by the natural pacemaker of the heart which is called the sinoatrial (or sinus) node.

Stent thrombosis

The development of a thrombus within an artery after implantation of a stent. A stent is a scaffold that is placed into diseased peripheral or coronary arteries. However, the body may have an immune response to the stent, leading to an inflammatory response and subsequent thrombosis.

Stroke

A sudden interruption in the blood supply of the brain. Ischaemic stroke, the most common type of stroke, occurs when an artery supplying blood to the brain becomes blocked, causing the surrounding brain tissue to die.

Syncope

The medical term for fainting, defined as a transient loss of consciousness and postural tone, characterized by rapid onset, short duration and spontaneous recovery.

Tachycardia

An abnormally rapid or irregular heart rhythm, where the heart is not able to efficiently pump oxygen-rich blood to the body.

Tachypnoea

Abnormally rapid breathing (also known as polypnoea).

Thrombectomy

Surgical excision of a thrombus from a blood vessel.

Thrombocytopenia

A reduction in the platelet count below the normal lower limit (usually defined as 150–450 ×109/l).

Thrombolytic therapy

The use of drugs to break up or dissolve blood clots. A commonly used thrombolytic drug is tissue plasminogen activator (tPA).

Thrombophilia(s)

An abnormality of blood coagulation that increases the risk of thrombosis. Otherwise known as a hypercoagulable or prothrombotic state, thrombophilias may be hereditary (i.e. protein C or S deficiency; Factor V Leiden) or acquired (environmental factors such as age, surgery or cancer).

Thromboplastin reagent

Thromboplastin reagents are used to monitor oral anticoagulant therapy with vitamin K antagonists for patients with thromboembolic disorders.

Thrombosis

The formation of a blood clot, or thrombus, inside a blood vessel. If this clot breaks loose and gets carried by the bloodstream to obstruct blood flow in another vessel, it becomes known as a thromboembolism.

Ticagrelor

A platelet aggregation inhibitor (Brilique®) produced by AstraZeneca, which when co-administered with acetylsalicylic acid, is approved for the prevention of atherothrombotic events in adult patients with acute coronary syndromes, including patients managed medically, and those who are managed with percutaneous coronary intervention or coronary artery by-pass grafting.

Transient ischaemic attack

A form of stroke or mini-stroke that occurs when the symptoms last only a short time (usually a few minutes) and are resolved in less than 24 hours.

Vascular disease

Hardening of vessels (atherosclerosis), caused by fatty deposits (plaques or atheroma). Subsequent vessel obstruction may lead to lack of blood supply to vital organs and tissues.

Venoactive

Having a toning effect on the veins. Venoactive drugs are a class of drugs derived from plant extracts commonly used to treat chronic venous insufficiency. They are powerful antioxidants that work by stimulating release of chemicals within the vein walls to strengthen the circulation and reduce inflammation and fluid collection within the tissues.

Ventilation/perfusion scanning

An imaging test commonly performed to check for the presence of a thrombus or abnormal blood flow inside the lungs (such as a pulmonary embolism), by evaluating the circulation of air (ventilation) and blood (perfusion) within the lungs using radioactive materials.