Vascular (1) (Common arterial conditions) Flashcards
arterial common conditions
- Abdominal aortic aneurysm
- Aortic dissection
- Peripheral arterial disease
- Chronic arterial insufficiency
abdominal aortic aneurysm
An abdominal aortic aneurysm (AAA) is defined as a dilatation of the abdominal aorta greater than 3cm.
pathophysiology of AAA
- Not understood
- Possible cause include atherosclerosis, trauma, infection, connective tissue disease e.g. Marfans
RF for AAA
- Smoking
- Hypertension
- Hyperlipidaemia
- Family history
- Male
- Increasing age
presentation of AAA
- Asymptomatic and incidental finding
- Symptomatic patients
- Abdominal pain
- Back or loin pain
- Distal embolization producing limb ischaemia
- Aortoenteric fistula
- Pulsatile mass felt in abdomen
presentation of ruptured AAA
- Tearing pain
- Hypotension
- Syncope
screening for AAA
- For all men in 65th years
investigations of AAA
- USSS
Follow up CT with contrast
which diameter discovered during a CT with contrast would indicate surgery was necessary
>5.5cm
or if rapidly enlarging
*In the UK, any AAA ……cm requires notification to the DVLA and disqualifies from driving until repaired.
>6.5cm
medical management of AAA when
AAA is <5.5cm
Medical (if less than 5.5cm) management of AAA
- Monitored via Duplex USS
- 3-4.4cm- yearly US
- 4.5-5.4cm- 3 monthly US
- Reducing CVS RF
- Smoking cessation
- Blood pressure control
- Statin and aspirin therapy
- Weight loss and exercise
surgical repair of AAA indicated when
- >5.5cm in diameter
- AAA expanding at >1cm/year
- Symptomatic AAA in pt who is otherwise fit
- In unfit patients, the AAA may be left until 6cm prior to repair due to significant risk of mortality from elective repair
surgical procedures for AAA
- Open repair midline laparotomy or long transverse incision, exposing aorta, and clamping the aorta proximally and the iliac arteries distally, before the segment is then removed and replaced with prosthetic graft
-
Endovascular repair involves introducing a graft via femoral arteries and fixing the stent across the aneurysm
- complication endovascular leak – aneurysm can expand and rupture
complications of AAA repair
- Rupture
- Retroperitoneal leak
- Embolization
- Aortoduodenal fistula
ruptured AAA
The risk of AAA rupture increases exponentially with the diameter of the aneurysm*, but the risk is also increased by smoking, hypertension, and female gender
presentation of ruptured AAA
- Abdominal pain
- Back pain
- Syncope
- Vomiting
- Haemodynamically compromised
- Pulsatile abdominal mass and tenderness
AAA rupture on CT
Classic triad of AAA
- Flank or backpain
- Hypotension
- Pulsatile abdominal mass
management of ruptured AAA
The patient should be transferred to the local vascular unit, with the vascular registrar, consultant, anaesthetist, theatre, and blood transfusion lab informed.
General
- High flow O2
- IV access 2x large bore cannula
- Urgent bloods (FBC, U&Es, clotting)
- Crossmatch for minimum 6U
Specific
- If patient unstable- immediate transfer to theatre for open surgical repair
- If patient stable- they will require a CT angiogram to determine whether aneurysm is suitable for endovascular repair
BEWARE when treating ruptured AAA
Any shock should be treated very carefully. Raising the BP will dislodge any clot and may precipitate further bleeding, therefore aim to keep the BP≤100mmHg (termed ‘permissive hypotension’, preventing excessive blood loss). As long as the patient is cerebrating, the BP is generally adequate.
layers of artery
The wall of an artery consists of the tunica intima (innermost layer), tunica media (middle layer), and tunica adventitia (outermost layer).
pathophysiology of aortic dissection
An aortic dissection is a tear in the intimal layer of the aortic wall, causing blood to flow between and splitting apart the tunica intima and media.
aortic dissection can be
anterograte or retrograde
Aortic dissections from the initial intimal tear can progress distally, proximally, or in both directions from the point of origin.
- Anterograde dissections propagate towards the iliac arteries
- Retrograde dissections propagate towards the aortic valve (at the root of the aorta)*.
Classification of aortic dissections
Aortic dissections are classified anatomically by two systems, DeBakey and Stanford.
RF for aortic dissection
- Hypertension
- Atherosclerotic disease
- Male gender
- Connective tissue disorders* (typically Marfan’s syndrome or Ehler’s-Danlos syndrome)
- Biscuspid aortic valve
presentation of aortic dissection
- Tearing chest pain radiating through to the back
- Tachycardia
- Hypotension
- Aortig regurg murmur
- End-organ hypoperfusion
buergers test
- Patient is supine
- Lift the patient’s legs to an angle of 45 degrees at the hip. Hold them there for 1-2 minutes, looking for pallor.
- Pallor indicates the arterial supply is not adequate to overcome gravity, suggesting peripheral arterial disease. Buerger’s angle refers to the angle at which the leg is pale due to inadequate blood supply. For example, a Buerger’s angle of 30 degrees means that the legs go pale when lifted to 30 degrees.
- The second part involves sitting the patient up with their legs hanging over the side of the bed. Blood will flow back into the legs assisted by gravity. In a healthy patient, the legs will remain a normal pink colour. In a patient with peripheral arterial disease, they will go:
- Blue initially, as the ischaemic tissue deoxygenates the blood
- Dark red after a short time, due to vasodilation in response to the waste products of anaerobic respiration- rubor
how to do an ABPI
1. With the patient lying on the examination couch, place the sphygmomanometer cuff over the left arm proximal to the brachial artery and position the Doppler probe on the brachial artery at a 45° angle (medial to the biceps tendon in the antecubital fossa).
2. Inflate the cuff 20-30 mmHg above the pressure at which the Doppler pulse is no longer audible and then deflate the cuff slowly, noting the pressure at which you first detect a pulse from the Doppler. This represents the systolic pressure in the vessel being assessed.
3. Now repeat steps 1 and 2 on the right brachial artery to assess systolic pressure.
4. Record the higher of the two systolic readings for use when calculating ABPI.
Measure the ankle pressure
1. Place the sphygmomanometer on the left ankle and position the Doppler probe over the posterior tibial artery, which is located posterior to the medial malleolus.
2. Inflate the cuff 20-30 mmHg above the pressure at which the Doppler pulse is no longer audible and then deflate the cuff slowly, noting the pressure at which you first detect a pulse from the Doppler. This represents the systolic pressure in the vessel being assessed.
3. Keep the sphygmomanometer in the same location but re-position the Doppler probe over the dorsalis pedis artery of the left foot, which is located lateral to the extensor hallucis longus tendon.
4. Assess the systolic pressure in the dorsalis pedis artery of the left foot by repeating step 2.
5. Record the highest of the two pressures obtained from dorsalis pedis (DP) and the posterior tibial artery (PTA) for use when calculating the left ABPI.
6. Repeat the same process on the right leg to calculate the right ABPI.
interpretation of ABPI results
spectral doppler analysis
waveform analysis of doppler
- tri-phasic is the most healthy
- mono-phasic is the least healthy
arteries of the leg
Subclavian steal syndrome
signs and symptoms that arise from retrograde (reversed) blood flow in the vertebral artery or the internal thoracic artery, due to a proximal stenosis (narrowing) and/or occlusion of the subclavian artery.
presentation
In periods of arm activity, reversal of the blood supply to the posterior cerebral circulation via the vertebral artery can result in a wide range of cerebral symptoms, including vertigo, diplopia, dysphagia, dysarthria, visual loss, or syncope.
Patients may also present with arm claudication due to the occluding lesions, such as arm pain or paraesthesia, made worse with arm movement.
