Peripheral Vascular Surgery MCQs: Questions for MCh/DrNB/ MRCS Exam Preparation (Part 2)

Arteriovenous Fistula (AVF)

• AVF (communication between an artery and vein) may be congenital or acquired (penetrating trauma or surgically                   created for hemodialysis).

• Structural effects on veins: Veins are arterialized (become dilated, tortuous and thick walled)

Physiological Effects of AVF

• Increased pulse pressure (Increased systolic and decreased diastolic).
• Increased venous return leading to increased HR and increased CO.
• Left ventricular enlargement and later cardiac failure may occur.

Clinical Signs

• A pulsatile swelling
• Thrill on palpation
• Continuous bruit on auscultation

                                                                           Diagnosis
• Duplex scan and/or angiography confirm the diagnosis.

                                                                            Treatment
• Treatment is by embolization.
• Excisional surgery (rarely) for severe deformity or recurrent hemorrhage.

• Thoracic outlet syndrome is diagnosed primarily by clinical evaluation and the diagnosis is based on reproducibility of           symptoms (resulting from compression of neurovascular bundle at the thoracic outlet) during mechanical provocative           maneuvers (Adson’s test or costoclavicular test or Hyperabduction test or Roos Arm Claudication test).

• Specific investigations (CT scan, MRI, Angiography, X-ray) are used to exclude other conditions and to establish the               associated diagnosis.

Allen’s Test
• Tests the adequacy of the blood supply to the hand from the radial and ulnar arteries and the arcade between them.
• Allen’s test is used to know the integrity of palmar arch (patency of radial and ulnar arteries). If these are patent, AVF can    be.

Method of Allen’s Test:

• Elevate the hand and apply digital pressure on the radial and ulnar arteries to occlude them.
• Ask the patient to make a fist several times.
• The tips of the finger should go pale. Release each artery in turn and observe the return of colour.

Types of Surgically Created Fistula:

Brescia-Cimino Fistula: Radial artery and cephalic vein

Snuffbox Fistula: Posterior branch of Radial artery and cephalic vein

Feinberg Fistula: Radial artery and basilic vein

safely ligated

• Critical lower limb ischemia is characterized by rest pain. Ulcers and gangrene may occur in patients with critical limb ischemia.

• Ischemic time for digits is upto 8 hours.
• Ischemic time for extremities is 4-6 hours.
• Organ containing bag should be placed in a solution of saline with ice.

Because gravity aids the delivery of arterial blood, classically, the patient with rest pain can obtain relief by simply hanging the leg over the side of the bed.

Arterial Ulcer

• Arterial insufficiency ulcers ischemic ulcers are mostly located on the lateral surface of the ankle or the distal digits.
• Most common on distal ends of limbs.

Etiology:

• Caused by lack of blood flow to the capillary beds of the lower extremities.
• Most often endothelial dysfunction is causative factor in diabetic microangiopathy and macroangiopathy.

Characteristic Features:
• Punched-out appearance.
• Intensely painful.
• Pulses are not palpable
• Associated skin changes (thin shiny skin, absence of hair, brittle nails)
Diagnosis:
• The lesion can be easily identified clinically.
• Arterial doppler and pulse volume recordings for baseline assessment of blood flow.
• Radiographs may be necessary to rule outosteomyelitis.
Treatment:
• Vascular surgery to revascularize the area.
• In infection: Antibiotics + Debridement.