Vascular and Interventional Radiology

Question 2

The anaesthetic technique associated with the highest rate of postprocedure
patency of a newly-created arteriovenous fistula is

a) Propofol TIVA
b) Brachial plexus block
c) Sedation + LA
d) Volatile

Answer 2

Regional -ie Brachial plexus

Anaesthesia Choice for Creation of Arteriovenous Fistula (ACCess) study protocol : a randomised controlled trial comparing primary unassisted patency at 1 year of primary arteriovenous fistulae created under regional compared to local anaesthesia

supraclavicular or Axillary block

Question 3

NP A 74-year-old presents for a femoral popliteal artery bypass procedure for peripheral limb ischaemia. Regarding its role in modifying their perioperative cardiovascular risk, clonidine:

a. Increased stroke
b. No change in complications
c. Increased death
d. Increased non fatal MI
e. Increased risk of non fatal cardiac arrest

Answer 3

REPEAT

e. Increased risk of non fatal cardiac arrest

POISE II
* clonidine 200mcg per day - did not reduce the rate of composite outcome of death or nonfatal MI - but it increased the risk of clinically important hypotension and nonfatal cardiac arrest
* aspirin initiation or continuation – no significant effect on rate of composite of death or non fatal MI but increased risk of major bleeding

Clonidine, as compared with placebo, was associated with an increased rate of nonfatal cardiac arrest

POISE 2 TRIAL

Question 4

20.1 A patient has foam sclerotherapy to treat a number of varicose veins. Following the procedure she stands, immediately loses consciousness and develops a unilateral limb weakness. The most likely mechanism is

a. Anaphylaxis
b. Intracranial bleed
c. Paradoxical gas embolus
d. Thromboembolic stroke

Answer 4

c. Paradoxical gas embolus

Although liquid-injection sclerotherapy is the criterion standard, foam sclerotherapy is becoming a popular alternative because of its efficacy and success rate.1 A potential complication of foam sclerotherapy is the formation of gas microemboli in the brain, which can lead to neurologic deficits.

https://www.degruyter.com/document/doi/10.7556/jaoa.2016.063/html?lang=en

Question 5

20.1 In a Blalock–Taussig shunt, blood passes to the pulmonary artery via the

a. Aorta
b. Subclavian artery
c. IVC
d. SVC
e. Left atrium

Answer 5

B

Question 6

21.2 You have been asked to provide general anaesthesia for a complex thoracic endovascular aortic aneurysm repair. After the placement of a lumbar drain the recommended safe time before the administration of intravenous heparin is

a) 1 hour
b) 4 hours
c) 6 hours
d) 12 hours

Answer 6

1 hour

ASRA: 1 hour

Although the occurrence of a bloody or difficult neuraxial needle placement may increase risk, there are no data to support mandatory cancellation of a case. Direct communication with the surgeon and a specific risk-benefit decision about proceeding in each case are warranted.

Currently, insufficient data and experience are available to determine if the risk of neuraxial haematoma is increased when combining neuraxial techniques with the full anticoagulation of cardiac surgery. We suggest postoperative monitoring of neurologic function and selection of neuraxial solutions that minimise sensory and motor block to facilitate detection of new/progressive neurodeficits.

NYSORA:
Administration of intravenous heparin intraoperatively should be delayed for at least 1 hour after epidural placement; a delay before administration of subcutaneous heparin is not required. In cases of full heparinization for CPB, additional precautions include delaying surgery for 24 hours in the event of a traumatic tap, tightly controlling the heparin effect and reversal, and removing catheters when normal coagulation is restored.

Question 7

23.1 A 50-year-old man presents with a subarachnoid haemorrhage. He undergoes
cerebral angiography and the frontal view is shown below. His cerebral aneurysm is
in the

(exact image on exam)

a. Anterior choroidal
b. Anterior communicating artery
c. MCA
d. PCA

Answer 7

b) anterior communicating artery

https://case.edu/med/neurology/NR/SubarachnoidHemorrhageAComm3.htm

https://www.thieme-connect.com/products/ejournals/pdf/10.1055/s-0039-1681979.pdf

https://case.edu/med/neurology/NR/NRHome.htm (scroll down to subarachnoid imaging area)

Question 8

21.2 A patient presents for endovascular clot retrieval after experiencing a right hemisensory loss and right homonymous hemianopia. The vessel most likely occluded is the left

a) ACA
b) MCA
c) PCA
d) AICA
e) PICA

Answer 8

Left PCA

Question 9

22.1 A 74-year-old man presents for a femoral popliteal artery bypass procedure for peripheral limb ischaemia. Regarding its role in modifying his perioperative cardiovascular risk, clonidine

a. Increased stroke
b. No change in complications
c. Increased death
d. Increased non fatal MI
e. Increased risk of non fatal cardiac arrest

Answer 9

e. Increased risk of non fatal cardiac arrest

POISE II
* clonidine 200mcg per day - did not reduce the rate of composite outcome of death or nonfatal MI - but it increased the risk of clinically important hypotension and nonfatal cardiac arrest
* aspirin initiation or continuation – no significant effect on rate of composite of death or non fatal MI but increased risk of major bleeding

Question 10

22.1 A 74-year old man complains of chest pain. An electrocardiograph is performed and displayed here. The occluded coronary artery could be the

a) RCA or LCx
b) RCA
c) LAD

Answer 10

RCA or LCx

https://litfl.com/mi-localization-ecg-library/

Question 11

23.1 A 60-year-old woman presents for thrombectomy with left lower leg ischaemia. She has not received any medications since presentation and takes none at home. The sole abnormality on laboratory testing is an activated partial thromboplastin time (APTT) of 52 seconds. The most likely cause of the raised APTT is

a. Cold agglutinins
b. Erroneous reading
c. Lupus anticoagulant
d. Factor VII deficiency
e. Haemophilia A

Answer 11

c. Lupus anticoagulant
(normal PT, raised APTT)

Lupus anticoagulant (more likely to be associated with thrombosis than bleeding)

https://www.uptodate.com/contents/image?imageKey=HEME%2F79969

Question 12

20.2 Idarucizumab reverses the anticoagulant effect of

a) Clopidogrel
b) Rivaroxaban
c) Dabigatran
d) Apixaban
e) Rivaroxaban

Answer 12

c) Dabigatran

Idarucizumab (Praxbind) is a monoclonal antibody to dabigatran

Dabigatran bleeding may be treated with:
- idarucizumab
- haemodialysis
- TXA will decrease fibrinolysis and has some effect
- FFP also has some effect

Humanized monoclonal antibody fragment (Fab) indicated in patients treated with dabigatran (Pradaxa) when reversal of the anticoagulant effects are needed for emergency surgery or urgent procedures, or in the event of life-threatening or uncontrolled bleeding
- 5 g IV, provided as 2 separate vials each containing 2.5 g/50 mL (see Administration)
- Limited data support administration of an additional 5 g

Dosage Modifications

Renal impairment: Renal impairment did not impact the reversal effect of idarucizumab; no dosage adjustment required
Hepatic impairment: Not studied
Dosing Considerations

This indication is approved under accelerated approval based on a reduction in unbound dabigatran and normalization of coagulation parameters in healthy volunteers; continued approval for this indication may be contingent upon the results of an ongoing cohort case series study

Question 13

21.1 Considering emergency front-of-neck airway access, the major blood vessel that is most likely to lie anterior to the trachea above the sternal notch is the

a) Brachiocephalic artery
b) Brachiocephalic Vein
c) Superior thyroid artery
d) Inferior thyroid artery
e) Carotid artery

Answer 13

a) Brachiocephalic artery

Major vessels, most commonly the brachiocephalic artery, traverse the anterior tracheal wall in up to 53% patients at the suprasternal notch

Question 14

20.1 Infrarenal aortic cross clamp will cause a(an):

a) Increased by 40% renal blood flow
b) Increased by 20% renal blood flow
c) Unchanged renal blood flow
d) Decreased 20% renal blood flow
e) Decreased 40%renal blood flow

Answer 14

e) Decreased 40%

Infra-renal aortic cross-clamping leads to a reduction in renal blood flow by up to 40%, as a result of an increase in renal vascular resistance of up to 75%.

The mechanism underlying this increased resistance is uncertain but may, in part, be a result of the associated decrease in cardiac output during aortic cross-clamping, as well as because of humoral mechanisms, which lead to increased release of renin. After declamping, there is a maldistribution of renal blood flow away from the cortex for at least 60 min.

Question 15

20.1 Patient with Fontan circulation and peritonism having induction for laparotomy. Drops sats on induction. Best move?

a. Decrease volatile
b. Reverse Trendelenberg
c. Decrease FiO2
d. Increase PEEP
e. Increase tidal volume

A 22-year-old man with a Fontan circulation is on your emergency list for an appendicectomy. He has had abdominal pain and vomiting for 3 days, and has a peritonitic abdomen. His preoperative arterial oxygen saturation is 95%. Shortly after induction he becomes hypotensive BP 80/45, and saturations fall to 75%. His condition is most likely to be improved by:

A. Increasing the inspiratory time.
B. Decreasing the ventilator tidal volumes.
C. Adding positive end-expiratory pressure (PEEP).
D. Positioning reverse trendelenberg.

Answer 15

A

Couldn’t find a clear source but we know;

A - will decrease venoplegia and improve venous return
B - Would not help, decrease VR
C - Don’t drop FiO2 when desatting…
D - increases PVR (unless below FRC) and reduces pulmonary flow
E - Same as above, increased PVR and reduces flow through pulmonary circuit

B. Decreasing the ventilator tidal volumes.

Patients who have undergone the Fontan procedure depend on blood flow through the pulmonary circulation without the assistance of the right ventricle. The difference between central venous pressure and systemic ventricular end-diastolic pressure (termed the “transpulmonary gradient”) is the primary force promoting pulmonary blood flow and, more importantly, cardiac output.

Circulation in the Fontan patient is promoted by low pulmonary vascular resistance. Positive-pressure ventilation with increased tidal volumes, as described above, can result in excessive intrathoracic pressures, leading to decreased venous return to the heart and increased pulmonary vascular resistance.
In periods of low oxygen saturation, 100% inspiratory oxygen is appropriate.
The addition of PEEP will increase intrathoracic pressure, reducing venous return.
Trendelenberg positioning would increase CVP and therefore bloodflow through pulmonary circulation.

Question 16

20.2 A patient has a peripherally inserted central catheter (PICC) inserted. The follow-up chest X-ray shows the tip positioned in the (Chest X-Ray shown)

a) Azygos vein
b) Coronary sinus
c) SVC
d) R atrium
e) L atrium

Answer 16

a) Azygos vein

Correct positioning in image

Question 17

20.1 During a tracheostomy, what vessel is most at risk beneath tracheostomy and above sternal notch?

a) Superior thyroid artery
b) Brachicephalic Vein
c) Brachiocephalic artery
d) Inferior thyroid artery
e) Carotid artery

Answer 17

brachiocephalic artery

BJA: Emergency FONA in airway management

“Major vessels, most commonly the brachiocephalic artery, traverse the anterior tracheal wall in up to 53% patients at the suprasternal notch.”

Question 18

22.1 A 60-year-old woman presents for thrombectomy with left lower leg ischaemia. She has not received any medications since presentation, and takes none at home. The sole abnormality on laboratory testing is an activated partial thromboplastin time (APTT) of 52 seconds. The most likely cause of the raised APTT is

a. Lupus anticoagulant
b. Erroneous reading
c. Cold agglutinins
d. Factor VII deficiency
e. Haemophilia A

Answer 18

a. Lupus anticoagulant

Factor VII
-> prolonged PT but not APTT

Cold Agglutinins
-> prolonged PT and APTT
-> “sole abnormality”

Haemophilia A
-> isolated prolonged APTT
-> associated with bleeding and not clotting

Lupus Anticoagulation
-> increased risk of clotting
-> prolonged APTT and normal PT

Question 19

21.1 A structure that is NOT clamped during a Pringle manoeuvre is the

a. Hepatic artery
b. Hepatic vein
c. Portal vein
d. Bile duct
e. Hepato-duodenal ligament

Answer 19

b. hepatic vein

Pringle Manoeuvre = clamping hepatoduodenal ligament (clamps hepatic artery, portal vein, CBD)

Question 20

22.1 You are about to anaesthetise a 25-year-old man for an open appendicectomy. He has a history of tricuspid atresia for which he has had a Fontan procedure. An important goal in managing his ventilation under anaesthesia is to ensure

a. Long I time, low pressures
b. Long I time, PEEP
c. Long E time
d. Spontaneous ventilation

Answer 20

c. Long E time

Spont vent not appropriate for this surgery as will require RSI so spont vent can’t be ensured

BJA: fontan circulation:
For relatively short procedures, Fontan patients are probably better off breathing spontaneously, as long as severe hypercarbia is avoided. For major surgery, or when prolonged anaesthesia is required, control of ventilation and active prevention of atelectasis is usually advisable. Potential disadvantages of mechanical ventilation in Fontan patients relate to the inevitable increase in mean intrathoracic pressure. This causes decreased venous return, decreased pulmonary blood flow, and hence, decreased cardiac output. Low respiratory rates, short inspiratory times, low PEEP, and tidal volumes of 5–6 ml kg−1 usually allow adequate pulmonary blood flow, normocarbia, and a low PVR. Hyperventilation tends to impair pulmonary blood flow, despite the induced respiratory alkalosis, because of the increased mean intrathoracic pressure.

https://academic.oup.com/bjaed/article/8/1/26/277637

Question 21

A 43-year-old man is undergoing an elective endovascular coiling procedure for an 8 mm middle cerebral artery aneurysm. Midway through the procedure the interventionalist tells you they have ruptured the aneurysm. All of the following are appropriate initial interventions EXCEPT

A. Decrease BP
B. Give protamine
C. Urgent transfer to theatre
D. Continue coiling
E. Mild hyperventilation

Answer 21

Answer: c. Urgent transfer to theatre

BJA Anaesthesia for interventional neuroradiology
https://academic.oup.com/bjaed/article/8/3/86/293346

Clinical signs of a rise in ICP or a sudden rise in blood pressure with or without a fall in heart rate should alert the anaesthetist to this possibility. Extravasation of contrast may also be seen. The goals are to increase coagulability by reversing heparin, decrease bleeding by lowering blood pressure (to the level before the bleed), control ICP with hyperventilation, head elevation, steroids and osmotic agents, control seizures, and initiate cerebral protection. Once the bleeding is controlled, the pressure may be raised to check for leaks. Usually, the coiling continues; rarely, a ventriculostomy may be required. If the coiling is unsuccessful, a rescue craniotomy and clipping will be required. Management may also involve performance of CT scans and subsequent transfer to ICU.

Question 22

Pulmonary hypertension is defined as a mean pulmonary arterial pressure greater than
a) 15mmHg
b) 20mmHg
c) 25mmHg
d) 30mmHg

Answer 22

b) 20mmHg

Question 23

Characteristics of post-operative visual loss due to vertebrobasilar ischaemia include

a) inattention
b) Vision returns in 24hrs
c) relevant afferent pupillary defect
d) diplopia

Answer 23

d) diplopia

Bilateral visual loss associated with insufficiency to posterior circulation so: parieto-occipital ischaemia, signs of stroke, visual agnosia, ophthalmoplegia or diplopia.

Question 24

When performing cannulation of the median cubital vein the structure that is LEAST likely to be inadvertently punctured or damaged is the

A) Radial artery
B) Median nerve
C) Brachial artery
D) Ulnar artery
E) Ulnar nerve

Answer 24

Repeat

e) Ulnar nerve

The cubital fossa is triangular in shape and consists of three borders, a roof, and a floor:
Lateral border – medial border of the brachioradialis muscle.
Medial border – lateral border of the pronator teres muscle.
Superior border – horizontal line drawn between the epicondyles of the humerus.
Roof – bicipital aponeurosis, fascia, subcutaneous fat and skin.
Floor – brachialis (proximally) and supinator (distally).
Contents:
- radial nerve
- biceps tendon
- brachial artery
- median nerve

Mnemonic for contents of the cubital fossa:
Really Need (radial nerve) Beer To (biceps tendon) Be At (brachial artery) My Nicest (median nerve).

Question 25

Cross clamping of the descending aorta is NOT expected to cause
(MADE UP ANSWERS)

a) Bacterial translocation
b) Decreased Renal perfusion
c) Abdominal compartment syndrome
d) Organ ischaemia
e) Decreased afterload

Answer 25

e) decreased afterload

https://academic.oup.com/bjaed/article/13/6/208/246828#2904603

Aortic cross-clamping and physiological considerations

The physiological effect of aortic cross-clamping during surgery varies with the level of the clamp in relation to the main aortic branches. Perfusion to the lower half of the body is therefore dependent on collateral circulation while the clamp is applied.

Clamp application increases the afterload of the heart and a sudden increase in arterial pressure proximal to the clamp; this can be attenuated with vasodilators [e.g. glyceryl trinitrate (GTN), sodium nitroprusside], opioids, or deepening of anaesthesia. These measures may also allow fluid loading in preparation for clamp release; however, the effect of vasoactive drugs is unpredictable; they may change haemodynamics without improving cardiac output and tissue perfusion due to blood redistribution.10

Increased afterload and left ventricular end-diastolic volume both increase myocardial contractility and oxygen demand. This increase in myocardial oxygen demand is usually met by an increase in coronary blood flow and oxygen supply, but can cause myocardial ischaemia.

After aortic cross-clamp release, peripheral vascular resistance decreases by 70–80%, causing a decrease in arterial pressure. Hypotension can also be caused by blood sequestration in the lower half of the body, ischaemia–reperfusion injury, and the washout of anaerobic metabolites causing metabolic (lactic) acidosis. This can cause direct myocardial suppression and profound peripheral vasodilatation. Coronary blood flow and left ventricular end-diastolic volume also decrease (almost 50% from pre-clamp levels) after clamp release.

Strategies to manage hypotension after aortic cross-clamp release include gradual release of the clamp, volume loading, vasoconstrictors, or positive inotropic drugs (e.g. ephedrine, meteraminol, phenylephrine, epinephrine, and norepinephrine). It is important to be aware that vasoactive drugs should only be used after adequate volume repletion.10 Management of aortic cross-clamp application and release requires excellent communication with the surgeon in order to anticipate and manage the physiological effects.

Question 26

In patients with symptomatic carotid stenosis, carotid endarterectomy can be performed
within two weeks of initial symptoms if there is/are

a) large stroke area
b) crescendo TIA symptoms
c) haemodynamic instability
d) Tandem Stenosis
e) contralateral occlusion

Answer 26

b) crescendo TIA symptoms

https://academic.oup.com/bja/article/99/1/119/269458

Ideally, patients presenting with a suspected TIA should have undergone investigation and, if appropriate, surgery within 2 weeks of presentation.

Question 27

You are inserting a pulmonary artery catheter in an intubated patient prior to cardiac surgery, and a significant amount of blood appears in the endotracheal tube. The most appropriate specific initial management is to

A. Remove PAC and insert DLT
B. Wedge PAC and insert DLT
C. Wedge PAC and insert bronchial blocker
D. Withdraw PAC 2 cm and insert DLT
E. Withdraw PAC and insert bronchial blocker
F. Inflate balloon

Answer 27

D. Withdraw PAC 2 cm and insert DLT

LITFL: Pulmonary haemorrhage after PAOP measurement

a life threatening time-critical emergency
pulmonary artery rupture caused by inflation of the pulmonary artery catheter (PAC) balloon during ‘wedging’ (measurement of the pulmonary artery occlusion pressure)
some experts advise against measuring PAWP because of the risk of pulmonary artery rupture
0.2% risk,  30% mortality

RISK FACTORS

pulmonary hypertension
mitral valve disease
anticoagulants
age >60 years

MANAGEMENT

Goals

prevent further pulmonary haemorrhage
stop bleeding
resuscitate

Call for help

ICU consultant
anaesthetist/ OT
cardiothoracic surgeon
interventional radiology

Resuscitation

A
    may have to be emergently intubated if not already
B
    FiO2 1.0
    controlled ventilation
    if able to recognize which lung is haemorrhaging may be able to perform lung isolation (insert single lumen tube into unaffected side, exchange for a double lumen tube or use bronchial blocker with bronchoscopic assistance)
    apply PEEP to tamponade wound
C
    large bore IV cannulae, fluids, blood products, inotropes

Specific therapy

Lay the patient ruptured side down
withdraw pulmonary catheter 2-3 cm with balloon down then refloat PAC with balloon inflated to occlude pulmonary artery (to try to tamponade bleeding)
stop antiplatelet agents and anticoagulants
give reversal agents:
— protamine for heparin
— platelets for anti-platelet agents
give blood products as indicated by FBC, coags and clinical state
interventions
— angiogram or bronchoscopy to isolate pulmonary vessel involved
— if bleeding doesn’t settle will require lobectomy

Question 28

A transjugular intrahepatic portosystemic shunt procedure is contraindicated in
patients with:

a) Hepatorenal syndrome
b) Refractory ascites
c) Severe TR
d) Variceal bleeding
e) Budd chiari

Answer 28

c) Severe tricuspid regurgitation (TR)

Severe TR can lead to increased right atrial pressure, which may impede the proper function of the TIPS and worsen outcomes.

Contraindications:
Severe Hepatic encephalopathy
Severe Pulmonary Htn
Severe TR
Multiple Hepatic Cysts
Coagulopathy (relative contraindication)