Vascular Glossary: Terms Explained
Plain-English definitions of the words you may meet in a vascular scan report, a referral letter or a consultation, from aneurysm to venous ulcer. Each term links to the full guide.
A
Abdominal aortic aneurysm (AAA)
An abdominal aortic aneurysm is an abnormal enlargement of the aorta in the abdomen. It often causes no symptoms and is commonly found by chance or by screening ultrasound. Repair is generally considered at about 5.5 cm in men and 5.0 cm in women, or earlier if it grows quickly or causes symptoms.
Acute limb ischaemia
Acute limb ischaemia is a sudden loss of blood supply to an arm or leg, often from a blood clot on the arterial side of the circulation. A suddenly painful, cold, pale or blue foot, especially with new numbness, weakness or difficulty moving it, is an emergency: call 995.
Aneurysm
An aneurysm is an abnormal enlargement of part of an artery, most often the aorta, which grows like a balloon. The risk is that it can burst. Many aneurysms cause no symptoms, so they are often found by chance, and most found early are watched with repeat scans rather than repaired straight away.
Angioplasty
Angioplasty opens a narrowed or blocked artery from inside the blood vessel. A thin wire is passed across the narrowing and a balloon is inflated to widen it. A balloon may be used alone or with a stent to support blood flow. It is usually done through a needle puncture under local anaesthetic.
Ankle-brachial pressure index (ABPI)
The ankle-brachial index compares the blood pressure at the ankle with the pressure in the arm, using a blood pressure cuff and a hand-held Doppler probe. A low value suggests narrowed leg arteries. In diabetes, calcified ankle arteries can give a falsely reassuring reading, so a toe pressure may be measured as well.
Anticoagulation (blood thinners)
Anticoagulation means blood-thinning medicine. It is the standard treatment for almost every deep vein thrombosis and pulmonary embolism, and most people need nothing else. For selected clots confined to the calf veins, ultrasound surveillance may be recommended instead. Clot removal, when used, is added to blood thinners, not instead of them.
Aortic dissection
An aortic dissection occurs when blood enters a tear in the inner lining of the aorta and separates the layers of its wall, creating a second channel called a false lumen. It is different from an aneurysm, although one can lead to the other. Sudden severe chest, back or abdominal pain needs a 995 call.
Arteriovenous (AV) fistula
An AV fistula is a dialysis access made by an operation that joins an artery to a vein, usually in the arm. The vein enlarges over several weeks so it can be needled for haemodialysis. A functioning fistula can provide durable access with relatively low infection risk, but some develop slowly or need further treatment.
Arteriovenous (AV) graft
An AV graft is a dialysis access that uses a manufactured tube to connect an artery and a vein, usually in the arm. Some grafts can be used sooner than fistulas, depending on the device and healing. Grafts can develop infection, narrowing and clotting, so they need careful use and regular follow-up.
Atherectomy
Atherectomy uses a catheter device to remove or modify plaque inside a narrowed artery, in selected cases. It is one of the tools used alongside balloon angioplasty and stents when treating leg arteries from the inside. It is not needed for every blockage; the choice depends on the artery, the type of plaque and the device evidence.
Atherosclerosis
Atherosclerosis is the build-up of plaque in the walls of arteries, which narrows or blocks them. It is the usual cause of peripheral arterial disease in the legs, and it can also affect the heart and the carotid arteries that supply the brain. The same risk factors, such as smoking, diabetes and high blood pressure, drive it everywhere.
B
Bypass surgery
Bypass surgery creates a new route for blood around a blocked artery. The new route is usually one of your own veins or, sometimes, a synthetic graft. The blockage, available veins, general health and your priorities shape the choice, and a bypass is not automatically a last resort, nor is a catheter procedure automatically better.
C
Carotid artery disease
Carotid artery disease is narrowing of an artery in the neck that supplies blood to the brain, usually caused by plaque. It can cause a stroke or a mini-stroke (TIA), and it may cause no symptoms beforehand. A neck duplex ultrasound shows the narrowing, and treatment aims to lower the risk of stroke.
Carotid artery stenting
Carotid artery stenting treats a narrowed neck artery from the inside, placing a stent across the narrowing to hold it open. Like endarterectomy, it aims to lower the risk of stroke rather than remove every possible cause. TCAR is one form of carotid stenting, performed through a small incision low in the neck.
Carotid endarterectomy
Carotid endarterectomy is an operation that removes plaque from the carotid artery through an incision in the neck and an opening in the artery, which is then closed. It is one of the procedures used to lower the risk of stroke from a narrowed neck artery, alongside carotid stenting and medical treatment.
CEAP classification
CEAP is the international scale vascular surgeons use to describe venous disease, from C0 (no visible signs) through varicose veins and swelling to skin changes and ulcers. Skin darkening, hardening and ulcers are graded C4 to C6, the stage at which guidelines recommend a duplex scan and treatment of the underlying reflux.
Chronic limb-threatening ischaemia (CLTI)
Chronic limb-threatening ischaemia is the most severe, longstanding form of peripheral arterial disease. The blood supply is so poor that the foot hurts at rest, often at night, or wounds do not heal. It needs prompt assessment by a vascular surgeon, because restoring blood flow may be needed to save the limb.
Chronic venous insufficiency
Chronic venous insufficiency means the veins are not returning blood from the legs as effectively as they should, usually because valves leak. It can cause aching, swelling, skin darkening, eczema and, in advanced cases, ulcers around the ankle. A duplex scan shows which veins are responsible and whether treatment would help.
Claudication
Claudication is cramping, aching or tightness in the calf, thigh or buttock that comes on with walking, settles with rest and returns at a similar distance. It is a sign of narrowed leg arteries. The word comes from the Latin for to limp. It is also a warning sign of artery disease elsewhere.
Compression stockings
Compression stockings are graduated elastic stockings that squeeze the leg to support the veins. Properly selected stockings can help aching and swelling, but they do not repair faulty valves. Strong compression may be unsafe when the leg arteries are narrowed, so the circulation should be checked before strong stockings are started.
CT angiography
CT angiography is a CT scan taken while contrast dye flows through the arteries, giving a detailed three-dimensional picture of the blood vessels. It provides detailed information for most aortic problems and is the usual scan for planning an aneurysm repair. MRI or echocardiography may be used for particular questions.
D
Deep vein thrombosis (DVT)
A deep vein thrombosis is a blood clot in a deep vein, most often in the leg or pelvis. It typically causes a swollen, painful, warm leg and needs a scan the same day. The main dangers are a clot travelling to the lungs (pulmonary embolism) and lasting damage to the vein.
Doppler
Doppler is an ultrasound technique that measures movement, especially blood flowing through a vessel. The machine converts that movement into a signal that can be heard or measured, showing the speed and direction of flow. In a duplex scan, Doppler flow information is combined with the ultrasound picture of the vessel.
Drug-coated balloon
A drug-coated balloon is an angioplasty balloon coated with medication. When it is inflated, it delivers the medication to the artery wall to reduce the tissue growth that can contribute to recurrent narrowing. Whether it is appropriate depends on the artery, the lesion and the device evidence for that situation.
Duplex ultrasound
A duplex ultrasound combines a picture of the blood vessel with Doppler information about blood flow. It shows where blood is flowing, in which direction, and whether there is a narrowing, blockage, reflux or clot. It is quick, uses no radiation, and is the first test for most vein and artery problems.
E
Endoleak
An endoleak is blood flow that continues inside the aneurysm sac, outside the stent graft, after EVAR. It is the commonest finding on scans after stent-graft repair. The blood is still inside the aorta, not leaking out of it. What matters is the type of endoleak and whether the sac is growing.
Endovascular surgery
Endovascular surgery is keyhole treatment of blood vessels from the inside. Through a small puncture in an artery or vein, wires, catheters, balloons, stents and stent grafts are guided by imaging to the problem. It is used for aneurysms, narrowed or blocked arteries, clots and some vein problems.
Endovenous laser ablation (EVLA)
Endovenous laser ablation, also called EVLT, closes a faulty superficial vein from inside using laser energy to generate heat. A thin fibre is placed in the vein through a needle under ultrasound guidance and local anaesthetic. It works on the same principle as radiofrequency ablation, using a different energy source.
EVAR (endovascular aneurysm repair)
EVAR repairs an abdominal aortic aneurysm from inside. A stent graft is passed through the groin arteries, using small incisions or punctures, and positioned with imaging so blood flows through the graft rather than the aneurysm. It avoids a large abdominal incision but needs long-term follow-up scans.
F
Fenestrated and branched EVAR
Fenestrated and branched EVAR are endovascular repairs for selected complex aneurysms that involve the arteries to the kidneys, bowel or liver. A fenestration is a carefully positioned opening in the graft fabric; a branch is a side limb. These keep blood flowing to the organ arteries while the aneurysm is sealed.
Fistulogram
A fistulogram is an X-ray examination of a dialysis access, using contrast dye to show narrowings, blockages or clot along the fistula or graft and its veins. It may be combined with examination and duplex ultrasound, and a narrowing that is found may be treated with balloon angioplasty.
Frozen elephant trunk (FET)
The frozen elephant trunk is an operation for disease of the aortic arch. It combines open reconstruction of the arch with a stented graft component that extends into the descending aorta in the chest. It is used for selected aneurysms and dissections that involve the arch.
I
Iliac vein compression (May-Thurner)
Iliac vein compression is narrowing of a main vein in the pelvis, often where an artery crosses over it, which is called May-Thurner syndrome. It can contribute to a large deep vein thrombosis or a swollen leg that never recovers. In selected patients, it can be treated with venoplasty and a vein stent.
L
Ligation and stripping
Ligation and stripping is the traditional operation for varicose veins. Ligation closes off an abnormal connection between a surface vein and a deep vein, and stripping removes a length of the faulty vein. It is now kept for cases where endovenous treatments are unsuitable.
M
Microphlebectomy
Microphlebectomy removes selected varicose veins near the skin through small openings, usually under local anaesthetic. It is often done at the same sitting as an endovenous treatment of the main faulty vein, to deal with the visible bulging branches. The scan decides which veins are treated.
O
Open aortic surgery
Open aortic surgery repairs a diseased part of the aorta through a surgical incision, usually replacing the affected segment with a durable synthetic graft. It is performed under general anaesthesia, and recovery usually takes longer than after an endovascular repair. The graft and remaining aorta still need follow-up.
P
Peripheral arterial disease (PAD)
Peripheral arterial disease is narrowing or blockage of the arteries that supply the legs, usually caused by atherosclerosis. It can cause pain on walking (claudication), pain at rest or wounds that do not heal. Many people are managed with medicines, risk-factor control and exercise; some need a procedure.
Phlegmasia
Phlegmasia is a rare, severe form of deep vein thrombosis in which the clot blocks so much of the venous drainage that the whole leg becomes very swollen, painful and discoloured. It can threaten the limb and requires emergency specialist care. Most people with a DVT do not develop it.
Post-thrombotic syndrome (PTS)
Post-thrombotic syndrome is a lasting problem with venous drainage after a deep vein thrombosis. The clot may scar the vein, and the leg can remain swollen, heavy, aching or dark around the ankle, sometimes with ulcers. A vascular review can check whether a blocked or narrowed vein can still be improved.
Pulmonary embolism (PE)
A pulmonary embolism occurs when a blood clot, usually from a deep vein thrombosis in the leg, breaks off, travels through the heart and lodges in the arteries of the lungs. It can cause sudden breathlessness, chest pain or collapse and can be fatal. Call 995 for these symptoms.
R
Radiofrequency ablation (RFA)
Radiofrequency ablation treats a faulty superficial vein by using controlled heat to close it from within. A thin catheter is placed in the vein through a needle under ultrasound guidance and local anaesthetic. Blood then reroutes through healthy veins. It is a usual first choice for a suitable saphenous vein.
S
Sclerotherapy
Sclerotherapy uses an injected medicine, called a sclerosant, to damage the lining of a selected vein so that it closes. It can be given as a liquid for small veins or as an ultrasound-guided foam for larger ones. More than one session may be needed, and results vary between veins.
Stenosis
Stenosis means narrowing of a blood vessel. In arteries it is usually caused by plaque and can reduce blood flow to the legs, brain or other organs; in veins it may follow a clot or outside compression. A duplex scan shows where a stenosis is and how much it affects flow.
Stent
A stent is a small metal mesh tube placed inside a narrowed artery or vein to hold it open after it has been widened with a balloon. Whether one is used depends on the vessel and the lesion. A stent can also narrow or block later, so follow-up is still needed after it is placed.
Stent graft
A stent graft is a fabric tube supported by a metal frame, used to repair an aneurysm from inside. It is delivered folded through an artery, usually in the groin, then opened inside the aorta so blood flows through it rather than into the aneurysm: a pipe within a pipe.
T
TCAR (transcarotid artery revascularisation)
TCAR is a form of carotid stenting performed through a small incision low in the neck. It accesses the carotid artery directly and temporarily reverses blood flow through a protection circuit while the narrowed segment is treated. It still carries risks, including stroke, bleeding and later narrowing of the stent.
TEVAR (thoracic endovascular aortic repair)
TEVAR treats disease of the aorta in the chest from inside. A stent graft is introduced through an artery, usually in the groin, and positioned in the thoracic aorta with imaging. It is used for selected thoracic aneurysms and dissections, and it is different from standard abdominal EVAR.
Thoracoabdominal aneurysm
A thoracoabdominal aneurysm extends from the chest into the abdomen and involves the segment of aorta that gives off the arteries to the kidneys, bowel, liver and spinal cord. Its repair, whether open or with a branched stent graft, is a much larger undertaking with different risks from an abdominal aneurysm.
Thrill (dialysis access)
The thrill is the buzzing vibration you can feel over a working AV fistula or graft, caused by fast blood flow through it. Learning how your access normally feels lets you notice change. If the thrill disappears, contact your dialysis unit or the vascular team urgently, because the access may have clotted.
Thrombectomy
Thrombectomy is removal of a blood clot. Mechanical thrombectomy uses a catheter-based device, passed through a vein or artery, to remove clot from inside the vessel. It is considered in selected cases, such as a large clot in the pelvic or upper thigh veins, or a pulmonary embolism.
Thrombolysis
Thrombolysis uses clot-dissolving medicine. In catheter-directed thrombolysis, the medicine is delivered through a catheter placed directly into the clot. It is considered for selected patients, usually with a large, recent clot in the pelvic or upper thigh veins, and is given in addition to blood thinners.
Transient ischaemic attack (TIA, mini-stroke)
A transient ischaemic attack, or mini-stroke, causes brief stroke-like symptoms such as facial droop, arm weakness, slurred speech or loss of vision in one eye. Even if it passes, it warns of a possible further stroke. You cannot safely tell a TIA from a stroke at home: call 995 at once.
Tunnelled dialysis catheter
A tunnelled dialysis catheter is a tube that reaches a large vein and provides dialysis connections outside the body. It passes under the skin before entering the vein. It allows dialysis to start or continue while a fistula or graft is created or heals.
V
Varicose veins
Varicose veins are enlarged, twisted veins visible beneath the skin, usually in the legs. They often develop when one-way valves do not close effectively, allowing blood to flow backwards. They can ache, swell, bleed or lead to skin changes, so they are not always only a cosmetic problem.
Vascular surgeon
A vascular surgeon is a specialist in the blood vessels outside the heart and brain: the aorta, the arteries to the neck and legs, and the veins. Vascular surgeons diagnose with scans and treat with medicines, keyhole endovascular procedures and open surgery, choosing the approach that fits each patient.
VenaSeal (vein glue)
VenaSeal is a branded medical cyanoacrylate adhesive system used to close selected superficial leg veins with symptomatic reflux. The glue is placed inside the vein through a catheter under ultrasound guidance. It uses no heat, so it needs less local anaesthetic than heat-based closure.
Venous reflux
Venous reflux is blood flowing backwards down a leg vein because its one-way valves do not close properly. It raises pressure in the veins near the skin, which stretch into varicose veins and, over years, can cause swelling and skin change. A duplex scan shows where the reflux starts.
Venous thromboembolism (VTE)
Venous thromboembolism is the umbrella term for blood clots in the veins. Deep vein thrombosis and pulmonary embolism are different presentations of the same condition. Clots are more likely when blood slows after surgery, long flights or immobility, and the risk is assessed individually.
Venous ulcer
A venous ulcer is a wound, usually near the inner ankle, that forms on skin damaged by long-standing venous reflux. A minor knock can open a wound that does not heal. Guidelines recommend treating the faulty superficial veins rather than relying on compression alone, alongside wound care.
Have a question about your own scan report? WhatsApp Dr Choong on +65 9027 8636 (he usually replies within the hour), or see the vascular FAQ and all contact options.