Non-Invasive Vascular Unit
The diagnostic examinations carried out in the Non-Invasive Vascular Unit are a study of blood vessels, arteries & veins. These examinations are performed using ultrasound.
Ultrasound is like ordinary sound except it has a frequency higher than the human ear can hear. It is sent into the body by a transducer resting on the patient’s skin to which gel has been applied and the sound is reflected off internal structures such as veins or arteries. The returning echoes are received by the transducer and turned, by a means of an electronic instrument, into sound and/or an image of the internal structures on a viewing screen.
The examination is painless and requires no preparation.
Monday - Thursday: 8.30am to 4.30pm
Friday: 8.30am to 4.00pm
- Telephone: (01) 809 3155
- Fax: (01) 809 3142
- Email: firstname.lastname@example.org
- Director: Dr. Patricia Fitzgerald
- Chief II Vascular Technician: Dermot Murphy
- Vascular Technicians: Karen O'Brien, James Kelly, (Basic Post Vacant)
- Secretaries: Francis Fitzsimons
We provide ultrasound examinations of:
- The Carotid & Vertebral Arteries
- The Aorta & Iliac Arteries
- The Venous System: Varicose Veins, Deep Vein Thrombosis
- Arteriovenous Fistula (AVF)
- AVF Patency
- Bypass Graft
- Segmental Pressures: Upper & Lower
- Digit Pressures
- Digit Waveforms
- Compression Stockings
The Carotid and Vertebral arteries are the main arteries on either side of the neck, which supply blood to the head. The examination is performed to determine if there is any alteration to the walls of these arteries as a result of atherosclerosis. An alteration to the wall can effect blood flow, particularly to the brain, which can result in symptoms such as stroke.
While the patient is lying flat, a cool gel is placed on the skin of the neck and a probe is used to scan the arteries.
The aorta is one of the most important arteries in the body. It carries blood from the heart through the abdomen supplying many other arteries such as the carotid arteries. In the lower abdomen the Aorta divides into the Iliac arteries which supply blood to the legs. Examination of the Aorta and Iliac arteries is performed to determine if they are aneurysmal. An aneurysm is an uncontrolled dilatation of the artery which can continue to increase in size and is of risk of rupture.
A cool gel is placed on the skin of the abdomen while the patient is lying flat. A probe is then used to scan the arteries.
Veins return blood from the body to the heart. Many veins have valves, which ensure that the blood only flows in one direction, i.e., towards the heart.
Veins become varicosed when the valves within them fail to operate adequately allowing some backflow of blood. This can result in the dilation of veins which can become visible as “bulges” on the legs.
The examination is painless and requires no preparation. The patient will be required to change into a gown in a private cubicle prior to the examination. While the patient is standing cold gel is placed on the skin of the leg starting at the groin. A probe is then used to scan the veins from the groin to behind the knee. The calf is compressed intermittently throughout the exam.
Deep Vein Thrombosis (DVT)
A DVT develops when the blood in a deep vein clots obstructing or hindering the return of blood to the heart. This can result in swelling, pain and redness of the affected limb. A major risk associated with DVT is a pulmonary embolism.
The examination is painless and requires no preparation. The patient will be required to change into a gown in a private cubicle prior to the examination. While the patient is lying flat, cold gel is placed on the skin and a probe used to assess the vein. Using the probe the technician will gently press on the skin to compress the vein throughout the exam. In the case of the lower limb the deep veins are assessed from the calf to the groin and if necessary in the abdomen. For an upper limb examination the veins are assessed from the wrist to the shoulder.
Some dialysis patients may require the formation of an AVF for vascular access. Surgically an artery and vein are linked, usually in the arm. This results in the dilation of the vein, with high velocity blood flow within. The AVF can then be used as the site for dialysis. Using ultrasound scanning the most suitable artery and vein for AVF formation is determined before surgery.
With the patient seated a tourniquet is placed around the upper arm. Cool ultrasound gel is placed skin and a probe is used to assess the vein and then the artery. The vein is assessed and any abnormality noted. If the vein appears suitable it is measured throughout and then its position marked on the arm using a skin marker. The artery is then assessed and again any abnormality noted. As with the vein if the artery appears suitable it is measured throughout however the artery is not marked.
After formation of an AVF it may require scanning to assess patency.
With the patient in a seated position cool ultrasound gel is applied to the skin and a probe is used to assess the blood flow in the AVF.
A surgeon may use a natural or synthetic graft to bypass an area of severe arterial disease. The graft may be regularly assessed to ensure it is adequately working.
The patient is assessed while lying flat. Cool ultrasound gel is placed on the skin and a probe is used to assess the graft from one end to the other.
A pseudoaneurysm can occur when a punctured artery does not heal allowing blood to flow into the surrounding area. Using ultrasound the artery can be assessed to see if such a “leak” exists.
The examination is painless and requires no preparation. The patient will be required to change into a gown in a private cubicle prior to the examination. While the patient is lying flat, cold gel is placed on the skin and a probe used to assess the artery.
The peripheral arterial system of the limbs can be affected by atherosclerosis which alters the wall of the vessel – peripheral vascular disease (PVD). This can adversely affect blood flow through the artery resulting in symptoms such as claudication (pain on exercise). Blood pressure is used as indication of the extent of the affect on blood flow.
- Lower Limb Exam
Blood pressure cuffs are applied to the arms above the elbow and to the legs. On the legs the cuffs are applied around the ankles and in some cases along the legs above and below the knee. With the patient lying flat an ultrasound probe is used to locate the arteries at the wrist and ankle. The cuffs are inflated briefly in turn (which may be slightly uncomfortable for some patients). A pressure measurement of toes may also be performed using a small toe cuff and probe. Some patients may be required to perform an exercise test which involves walking on a treadmill at a steady speed for a set time followed be repeat measurements of the ankle pressures.
- Upper Limb Exam
Blood pressure cuffs are applied to the arms above and below the elbow. With the patient seated an ultrasound probe is used to locate the arteries at the wrist. The cuffs are inflated briefly in turn (which may be slightly uncomfortable for some patients). A pressure measurement of the fingers will also be performed using a small finger cuff and probe. The arms will then be exercised and pressure measurement of the fingers will then be repeated.
Raynaud’s Syndrome is a condition which affects the microvessels of the fingers and toes. It results in the constriction of these small vessel particularly when cold resulting in colour change of the fingers and pain.
Finger pressure cuffs are placed around the base of the finger and a finger probe is applied to the top of the finger. A pressure measurement is then taken. The fingers are then immersed in ice for a set time and the pressure measurement repeated. Heat is then applied to the fingers and a further pressure measurement made.
In the presence of an Arteriovenous Fistula (AVF) a condition called Steal Syndrome can occur. This occurs when the AVF prevents adequate flow of blood to the fingers and/or hand.
With patient seated a finger probe is placed on the tip of the finger of the arm with the AVF. The arterial waveform is then recorded. The AVF is compressed and any change in the waveform recorded.
Compression stockings are used to encourage flow of blood into the deep venous system of the legs rather than the superficial veins. They are supplied with prescription only and measurements are made of the patient’s legs to determine size