Ch 108 Vascular surgery

Question 1

What are the three layers of blood vessels and how do they differ in arteries and vein?

Answer 1

• Tunica externa/adventitia - Connective tissue fibroblasts and collagen. This layer needs to be removed from the cut ends for vessel reconstruction
• Tunica media - Smooth muscle cells and elastic tissue
• Tunica intima - Endothelial cells
  The tunica media of a vein is thinner than that of an artery

Question 2

What veins carry oxygenated blood?
Where are the only venous sinuses located?

Answer 2

Pulmonary veins and umbilical vein
In the skull

Question 3

Name the following instruments

Answer 3

From left to right:
- Diamond-jawed needle holder
- DeBakey atraumatic forceps
- Metzembaum scissors
- Potts scissors
- Small and large right-angled forceps

Question 4

Name the following microvascular instruments

Answer 4

From left to right:
- Miscrovascular needle holders, without catch
- Curved Vannas microvascular dissecting scissors
- Straight adventitial scissors
- Jeweler’s forceps
- Curved and straight mosquito haemostats

Question 5

name the folowing vascular clamps

Answer 5

From left to right: a DeBakey atraumatic angled vascular clamp, DeBakey atraumatic tangential clamps, a DeBakey-Satinsky atraumatic tangential clamp, a Cooley atraumatic clamp, a DeBakey atraumatic multipurpose curved clamp, and a Castaneda atraumatic neonatal clamp.

Question 6

What sized suture is recommended in vascular surgery?

Answer 6

3-0 to 10-0
- Vessels with internal diameter of 4-6mm - 4-0/5-0
- 2-3mm - 6-0
- less than 2mm - 7-0/8-0

Nylon or polypropylene for arteries
Braided multifilament passed through mineral oil or bone wax for veins

Question 7

vessel dissection

Answer 7

• dissect as closely to the adventitia as possible, generally with a blunt-tipped, right-angled forceps or blunt-tipped fine Metzenbaum scissors.
• dissecting directly over the surface of a vessel closest to the skin, the surgeon can generally avoid inadvertent disruption of branching collaterals.

Question 8

Atraumatic devices for occlusion

Answer 8

• vascular clamps
• Potts loops
• single loops of suture, tape or Silastic
• Rumel tourniquets may be applied

Question 9

What is the most common biological vascular graft in veterinary patients?

Answer 9

Jugular vein

Question 10

What is the characteristic pattern on a perfused artery?

adventitial surface of the artery

Answer 10

Vaso vasorum

Question 11

List the main options for systemic anticoagulation in vascular surgery

Answer 11

Unfractionated heparin
Enoxaparin

Question 12

List the main options for local anticoagulation in vascular surgery

Answer 12

To prevent clot formation in vessels:
- ice-cold solution of 2% lidocaine, heparin, and 0.9% saline to thoroughly flush the isolated vessel

Question 13

List the options for incision orientation for venotomy/arterotomy

Answer 13

Longitudinal
Transverse (recommended in vessels under 4mm diameter)

Question 14

List the three options for vascular anastomosis

Answer 14

End-to-end
End-to-side
Side-to-side

Question 15

What is Kunlin’s technique?

Answer 15

Placing a horizontal mattress suture during vascular anastomosis to produce mild eversion and improve intima approximation

Question 16

What is the most common guide wire size used in endovascular surgery?

Answer 16

0.035 inch (0.012-0.052)

Question 17

Seldinger technique: involves inserting a needle, then a guidewire, followed by a catheter over the guidewire, all percutaneously

Question 18

What sized vascular sheath is most commonly used?

Answer 18

5-6Fr

Question 19

What vessels are typically used for access during endovascular procedures?

Answer 19

Femoral or carotid artery
Jugular vein

Question 20

List some endovascular techniques used in small animals

Answer 20

Central venous catheter placement
Subcutaneous venous access port
Embolotherapy and embolectomy

Question 21

What substances can be used for embolotherapy?

selectively occlude blood flow

Answer 21

Non-absorbable
- Polyvinyl alcohol
- Trisacryl gelatin microspheres
- Silk suture

Absorbable:
- Gelatin sponges
- Autogenous blood clot material

Liquid:
- Cyanoacrylate and Lipiodol

Mechanical:
- Metallic coils
- Ductal occluders

Question 22

List options for embolectomy

surgical removal of a thrombus/embolus to restore patency of a vessel

Answer 22

• Direct surgical removal
• Embolectomy balloon catheter
• Catheter directed thrombolytic therapy (tissue plasminogen activator)
• Rheolytic catheter (pulsatile, high velocity stream of saline)
• Stents - may be used in combo with thrombolytic therapy

Question 23

List potential caused of acquired AV fistulas

Answer 23

Poorly treated arterial injuries
iatrogenic en bloc ligation
traumatic arterial catheterisation
Extravasation of irritating substances
Trauma
Infection
Neoplasia
Surgically created for long-term venous access

Question 24

List options for treatment of AV fistulas

Answer 24

• Cyanoacrylate glue embolisation
• Ligation and division of the artery proximal and distal to communication

Question 25

Fortunately, collateral circulation in dogs permits sacrifice of major vessels when needed, including carotid and femoral arteries

Answer 25

Weisse et al reported on the use of percutaneous arterial embolization for the treatment of intractable epistaxis in three dogs. Embolization of one or both maxillary arteries with polyvinyl alcohol particles resulted in long-term control

Question 26

Evaluation of a microvascular anastomotic coupler for end-to-side arterial and venous anastomosis for feline renal transplantation Megan A. Mickelson 2020

Answer 26

Study design: In vivo experimental study Anastomosis was successful in all cats, and intraoperative hemorrhage was negligible. Intraoperative renal perfusion was considered excellent

Question 27

Surgical removal of a jugular aneurysm in a spaniel cross dog

Answer 27

Ligatures were placed; two proximal and two distal to (2/0 PDS) The patient was treated with prophylactic clopridogrel (2 mg/kg/day) for stump thrombus prevention

Question 28

Use of an autologous pericardial patch to repair a post-traumatic caudal vena cava cicatrix in a dog Winter 2024

Answer 28

obstruction of venous flow from the liver to the right atrium is termed Budd-Chiari syndrome kinking of the caudal vena cava in a dog, following blunt thoracic trauma, that was managed using a pericardial patch graft in cases of traumatic kinking of the vena cava it can be considered as a second-line treatment should dissection of the fibrotic band fail to reduce caudal caval pressures. Minimally invasive techniques should also be considered in animals where the lesion is considered untreatable at open surgery. other options: balloon dilation, stent