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Y5 - Surgery > Vascular > Flashcards

Flashcards in Vascular Deck (20):

Layers of the aortic artery

Aorta = elastic artery
- Tunica intima - endothelial cells
- Tunica media - smooth muscle cells, collagen
- Tunica adventitia - CT containing lymphatics, nerves, vasa vasorum (blood vessels that supply blood to the artery)


4 sections of the aorta

- Ascending aorta
- Aortic arch
- Thoracic (descending) aorta
- Abdominal aorta

Terminates at the level of L4 by bifurcating into L and R common iliac arteries


Abdominal aortic aneurysm definition

- Focal dilation (diameter >3cm) of the abdominal aortic artery involving all layers of the wall


Abdominal aortic aneurysm types

- Suprarenal
- Pararenal
- Infrarenal (most common - 85%)

Size and rupture risk:
- Small (3-3.9cm) - no risk of rupture
- Medium (4-4.9cm) - rupture risk 1%/yr
- Large (5-5.9cm) - rupture risk 5-10%/yr
- Very large (6-6.9cm) - rupture risk 10-20%/yr
- Giant (7-7.9cm) - rupture risk 20-40%/yr
>8cm - rupture risk 30-50%/yr


Risk factors - AAA

- NM: Family hx, older age, sex (m), CT disorder - Ehlers-Danlos syndrome, Marfan syndrome
- M: smoking, HTN, hyperlipidaemia, PVD


AAA - clinical features

Usually asymptomatic <4cm
- Abdominal pain
- Early satiety, nausea/vomiting (caused by compression of adjacent bowel)
- Urinary symptoms of bladder compression


AAA - Features on examination

- Midline pulsatile mass
- Aortic bruit


AAA - Investigations

- D-dimer - elevated

- Abdominal ultrasound
- Abdominal CT


AAA - Management

Conservative management
- Weight loss
- Increase physical activity
- Smoking cessation

Surgical repair
- EVAR - endovascular aortic repair - stent is placed inside the aneurysm via femoral artery cannulation
- Open repair - removes the dilated section of abdominal aorta and replaces it with synthetic graft material


AAA Rupture

AAA rupture
- Caused by a tear in the wall of the dilated abdominal aorta

Types of rupture:
- Contained - perivascular haematoma is sealed off by periaortic structures (pleura, pericardium, retroperitoneal space)
- Free rupture -> massive haematoma


AAA rupture - clinical features

- Hypotension, abdominal pain, pulsatile abdominal mass

- Abdominal distension
- Sudden onset of abdominal or flank pain
- Ripping sensation in the back
- Lower extremity pain, coolness, paralysis, paraesthesia
- Syncope


AAA rupture - management

- Immediate surgical stabilisation and repair - EVAR
- Using EVAR - can keep patient awake
- If you tried to put a rupture patient under anaesthesia -> BP would drop too low


Dialysis - definition

A process to filter waste products and remove excess fluid from the blood


Dialysis - indications

Indicated in patients who develop symptoms or signs attributable to kidney failure:
* eGFR <15
* Acid base or electrolyte abnormalities
* Inability to control volume status or BP
* Deterioration in nutritional status unresponsive to dietary intervention


Dialysis - Haemodialysis

- Blood is pumped from the AV fistula into a dialyser
- In the dialyser, waste products filter from the blood through an artificial membrane into a fluid called the dialysate
- Purified blood is pumped from the dialyser into the AV fistula
- The total amount of fluid returned can be adjusted
- Blood is removed distally and put back in proximally


Dialysis - peritoneal dialysis

- In peritoneal dialysis, the peritoneum acts as a filter -> has a large SA and rich network of blood vessels
- A fluid (dialysate) is infused through a catheter inserted through the abdominal wall into the peritoneal space within the abdomen
- The dialysate must be left in the abdomen for a sufficient time to allow waste products from the blood stream to pass slowly into it
- Then the dialysate is drained out, discarded and replaced with fresh dialysate


AV fistula types:

* Ideally in the non-dominant hand
1. Radiocephalic (radial artery, cephalic vein)
2. Brachiocephalic (brachial artery, cephalic vein)
3. Brachiobasilic (brachial artery, basilic vein)


AV Fistula - complications

- Steal - signs of steal - 6 Ps: paraesthesia, pulselessness, pallor, perishingly cold, pain, paralysis
- Stenosis
*Generally occurs at transition points
Signs of stenosis:
- Aneurysm formation
- High pressure on dialysis machine
- Bleeding after dialysis
- Wound
- Rupture
- Infection
- Thrombosis
- Occlusions


Assessing fistula function

- Location
- Graft vs. native
- Palpate for thrill
- Auscultate - bruit
- Palpate distal pulses


Assessing fistula function - Red flags

- Pulsatile fistula -> stenosis
- No thrill
- No bruit
- Lack of distal circulation