Vascular Emergencies

Question 1

State some of the vascular emergencies you need to be aware of

Answer 1

• Ruptured AAA
• Acute limb ischaemia
• Acute mesenteric ischaemia (see GI surgery)

Question 2

Describe the two types of AAA rupture

Discuss the prognosis of each

Answer 2

Intraperitoneal (20%)

• Rupture anteriorly into intraperitoneal space
• ~23L fluid capacity
• Cardiac output ~51L/min

Retroperitoneal (80%)

• Rupture posteriorly into retroperitoneal space
• Usually survive to get to hospital
• Will eventually rupture intraperitoneally

Question 3

Ruptured AAA has a high mortality; true or false?

Answer 3

True (>75%)

Question 4

Describe the presentation of a ruptured AAA

Answer 4

• Known AAA or pulsatile mass in abodmen
• Severe abdominal pain, non-specific, may radiate to back or loin
• Haemodynamic instability: tachycardia, hypotension, weak pulse
• Pale, cold, sweaty
• Mimic acute abdomen (bleeding causes peritoneal irritation)

Classic triad= abdo/back pain, pulsatile mass and hypotension. However, less than 1/3 o pts will have this triad.

Question 5

State some potential differential diagnoses for someone presenting with what appears to be a ruptured AAA

Answer 5

• MI with cardiogenic shock
• Massive PE
• Acute pancreatitis

Question 6

Someone has come in to A&E with ruptured AAA, what is your initial management?

Answer 6

• Oxygen 15L non-rebreath mask
• Gain IV access- 2 wide bore cannulas in antecubital fossa
• Take bloods (FBCs, U&Es, clotting, crossmatch minimum 6 units)
• Maintenance IV fluids to maintain systolic at <100mmHg
• Catheterise
• CONTACT VASCULAR SURGEON ASAP

Question 7

What is permissive hypotension?

Why do we aim for permissive hypotension in ruptured AAA?

Answer 7

• Permissive hypotension or hypotensive resuscitation is the use of restrictive fluid therapy, specifically in the trauma patient, that increases systemic blood pressure without reaching normotension
• Raising BP too much will dislodge any clots and may precipitate further bleeding. As long as pt is cerebrating BP is generally adequete

Question 8

Discuss the management (following immediate management) of a AAA if pt is:

• Haemodynamically stable
• Haemodynamically unstable

Answer 8

• Haemodynamically stable: CT angiogram to determine if suitable for endovascular repair
• Haemodynamicaly unstable: transfer straight to theatre for open surgical repair

Question 9

Define acute limb ischaemia

Answer 9

Sudden deterioration in aterial supply, in a previously stable limb, resulting in rest pain and/or other features of severe ischaemia of less than two weeks duration

Question 10

Why is it important that acute limb ischaemia is treated promptly?

Answer 10

Complete acute ischaemia will lead to extensive tissue necrosis within 6hrs of onset unless arterial circulation is restored. Prompt assessment & management to prevent limb loss.

Question 11

State some causes of acute limb ischaemia

*HINT: can be classified into three categories

Answer 11

• Embolisation *80% have cardiac cause
  
  • AF
  • MI
  • Ventricular aneurysm
  • AAA
  • Prosthetic heart valve
  • Mural thrombosis
• Thrombosis *60% is acute thrombosis in vessle with pre-existing atherosclerosis
  
  • ​Atherosclerosis
  • Popliteal aneurysm
  • Thrombotic conditions
  • Malignancy
  • Dehydration
  • Polycythaemia
• Others
  
  • ​Dissection
  • Trauma
  • Compartment syndrome
  • External compression

Question 12

Describe the presentation of acute limb ischaemia

Answer 12

Present with 6P’s (first 3 most common):

• Pain
• Pallor
• Pulselessness
• Parasthesia
• Parlysis
• Perishingly cold

Question 13

State some clinical features that are suggestive of an embolic cause of acute limb ischaemia

Answer 13

• Sudden onset
• Known embolic source
• Absence of previous claudication
• Normal pulses in other limb

Question 14

State some clinical features that suggest a thrombotic cause of acute limb ischaemia

Answer 14

• Previous history of intermittent claudication
• Slow onset or incomplete occlusion
• No obvious source of emboli
• Reduced or absent pulses on contralateral limb

Question 15

If pt with suspected acute limb ischaemia has ‘marble white’ limb what does this suggest?

Answer 15

Embolic cause (if was atherosclerotic collaterals may have formed due to pre-exisiting peripheral arterial disease)

Question 16

What does fixed/non-blanching mottling suggest?

Answer 16

Irreversible ischaemia

Question 17

What investigations would you do if you suspect acute limb ischaemia, include:

• Bedside
• Bloods
• Imaging

Answer 17

Bedside

• ECG: determine whether in AF
• VBG: lactate quicker

Bloods

• FBC
• Troponin
• Group & save
• Coagulation
• Thrombophilia screen
• U&Es
• Glucose

Imaging

• Hand-held arterial doppler
• Duplex USS both limbs: look for occlusion
• Consider CT angiography following USS: can prvice more information regarding anatomical location of occlusion to help decide operative approach

Question 18

Discuss the initial management of acute limb ischaemia

Answer 18

• 15L oxygen non-rebreathe mask
• IV heparin (5000U bolus then infusion of 1000U per hour)
• Appropriate analgesia e.g. morphine 1-10mg
• Correct hypotension if present with IV fluids
• Start treatment for associated cardiac condition if present (e.g. AF, MI)

Question 19

The Rutherford classification helps us determine suitable definitive management of acute limb ischaemia; describe the Rutherford criteria

Answer 19

Question 20

Conservative management of acute limb ischaemia can be considered in those with Rutherford categories ___ and ____?

What is the conservative mangement?

Answer 20

Rutherford categories 1 and 2a can be managed conservatively.

Give prolonged course of heparin. Monitor APPT regularly and review pt to check effectiveness. Surgical intervention may be required if no significant improvement seen.

Question 21

Discuss the management of rutherford category 2b acute limb ischaemia (following initial management)

Answer 21

Surgical intervention is mandatory- cannot wait overnight. Any imaging should not delay treatment. Treatment depends on is source is embolic or thrombotic:

Embolic

• Embolectomy via Fogarty catheter under LA or GA
• Bypass surgery

Thrombotic

• Angioplasty
• Bypass surgery
• Local intra-arterial thrombolysis

Question 22

Discuss the management of irreversible limb ischaemia (mottled, non-blanching apppearance with hard woody muscles/Rutherford category 3)

Answer 22

• Amputation
• Or palliative approach

Question 23

Discuss the long term management of acute limb ischaemia

Answer 23

Centred around reduced CVD risk and preventing reoccurence:

• Lifestyle (smoking cessation, regular exercise, weight loss)
• Treat underlying conditions that predispose to acute limb ischaemia
• Anti-platelet agents e.g. aspirin or clopidogrel
• Anticoagulation e.g. warfarin or DOAC
• If had amputation, require physio, OT & rehabilitation

Question 24

Reperfusion injury is one of the main complications of acute limb ischaemia. Explain what reperfusion injury is

Answer 24

Sudden return of oxygenated blood to the ischaemic muscles generates and releases oxygen radicals that cause cellular injury & oedema. This can lead to:

• Compartment syndrome
• Release of substances from cells:
  
  • Hyperkalaemia
  • Acidosis (H+)
  • AKI (myoglobin)

Hence most post-operative cases are managed in high dependency unit to monitor for these complications.