Vascular Disease in the Lower Limb Flashcards
Clinical Case:
- 93 years old
- Pain in right calf after walking 50m
- No tissue loss
- Ex smoker / not diabetic
- ABPI 0.6
Where is occlusion likely?
- ABPI indicates moderate arterial disease
- Intermittent claudication
Suggest a contract angiography (occlusion likely in superficial femoral artery which is the main artery of the lower limb)
What is ABPI?
The ankle-brachial pressure index (ABPI) is a non-invasive method of assessing peripheral arterial perfusion in the lower limbs.
ABPI is a ratio composed of the blood pressure of the upper arm (brachial artery) and the blood pressure of the lower limb (dorsalis pedis and the posterior tibial artery).
What does an ABPI of >1.2 indicate?
Calcified vessels often cause unusually high ABPI results.
Further assessments such as angiography are advised to accurately assess perfusion.
What does an ABPI of 1.0-1.2 indicate?
Normal result
What does an ABPI of 0.8-0.9 indicate?
Mild arterial disease: typical presenting features include mild claudication.
What does an ABPI of 0.5-0.79 indicate?
Moderate arterial disease: typical presenting features include severe claudication.
What does an ABPI of <0.5 indicate?
Severe arterial disease: typical presenting features include rest pain, ulceration and gangrene. This is also known as critical limb ischaemia.
What is contrast angiography?
Angiography is a type of X-ray used to check blood vessels.
Blood vessels do not show clearly on a normal X-ray, so a special dye needs to be injected into your blood first.
This highlights your blood vessels, allowing your doctor to see any problems.
What is the purpose of an angiography?
Your doctor uses the angiogram to check for blocked or narrowed blood vessels in your heart.
Is a contrast angiography an invasive procedure?
Yes - a catheter, is inserted into an artery (usually femoral) through a small incision in the skin. Once the catheter is guided to the area being examined.
What is a heart angioplasty?
Common procedure to open arteries in the heart that are clogged.
Angioplasty involves the use of a tiny balloon to widen the artery.
What is stent placement?
Common procedure to open arteries in the heart that are clogged.
A stent is a tiny wire-mesh tube that your doctor inserts into the artery. The stent stays in place to prevent the artery from closing.
Clinical Case:
- 55 years old
- Angioplasty within the last 24 hours
- Pulsatile lump at puncture site
- Bruising
- Observations are stable
What test is then needed?
Severe bruising: punctured artery too high and have gone above the inguinal ligament so blood tracks down the inguinal canal and into the scrotum.
This can lead to serious complications.
Duplex ultrasound then is needed
What is a duplex ultrasound?
A duplex ultrasound is a test to see how blood moves through your arteries and veins.
What is a pseudoaneurysm?
A dilatation of the artery –> a false aneurysm that is a collection of blood that forms between the two outer layers of an artery, the tunica media and the tunica adventitia.
i.e. doesn’t involve ALL the walls of the artery
Clinical Case:
- 60 years old
- Rest pain and tissue loss
- Cannot feel foot pulses but detected by Doppler
- ABPI <0.5
What test is needed next?
- ABPI indicates severe arterial disease
MRA
What is a Doppler?
A Doppler ultrasound is a noninvasive test that can be used to estimate the blood flow through your blood vessels by bouncing high-frequency sound waves (ultrasound) off circulating red blood cells.
How does a Doppler differ from a normal ultrasound?
A regular ultrasound uses sound waves to produce images, but can’t show blood flow.
What is an MRA?
A non invasive MRI study of the blood vessels. It utilises MR technology to detect, diagnose and aid the treatment of heart disorders, stroke and blood vessel diseases.
BUT takes longer than a CT.
Clinical Case:
- 60 years old
- Sudden onset pain
- Previous bypass
- Foot is cold
- No detectable pulses
- Still has sensation and movement
What does this indicate?
Indicates acute limb ischaemia
What are the signs and symptoms of acute limb ischaemia?
The 6 P’s:
- Pain
- Pallor
- Paraesthesia
- Paralysis
- Pulselessness
- Perishingly cold
Describe stage I of acute limb ischaemia
- Tissue viable
- Not immediately threatened
- No sensory loss
- No muscle weakness
- Doppler signal present
Describe stage II of acute limb ischaemia
- Tissue marginally threatened
- Salvageable
- Minimal sensory loss (toes) or none
- No muscle weakness
- Doppler signal often inaudible
Describe stage IIb of acute limb ischaemia
- Tissue immediately threatened
- Salvageable with immediate revascularisation
- Sensory loss in more than toes, rest pain
- Mild to moderate muscle weakness
- Doppler signal usually inaudible
Describe stage III of acute limb ischaemia
- Irreversible tissue injury
- Major tissue loss or permanent nerve damage
- Profound sensory loss
- Paralysis
- Doppler signal: arterial and venous inaudible
What is CT angiography?
A test that uses X-rays to provide detailed pictures of the heart and the blood vessels that go to the heart, lung, brain, kidneys, head, neck, legs, and arms. A CT angiogram can show narrowed or blocked areas of a blood vessel.
What organ can contrast put at risk?
The kidneys
Endovascular treatment options for narrowed/blocked vesels?
- Thrombolysis
- Aspiration/mechanical thrombectomy
- Angioplasty + stenting
Surgical treatment options for narrowed/blocked vessels?
- Surgical thrombectomy/embolectomy
- Bypass
