Editing Vascular techniques


* Sutures for vascular anastomoses/repairs
** Generally monofilament nonabsorbable - Prolene or PTFE (can minimise needle-hole bleeding)
**

{| class="wikitable"
|Vessel
|Suture size
|-
|Aorta
|2-0 or 3-0
|-
|Iliac
|4-0
|-
|Axillary, common carotid, CFA, SFA
|5-0
|-
|Internal carotid, popliteal, brachial
|5-0 or 6-0
|-
|Tibial and inframalleolar
|7-0 or 8-0
|}


Grafts

* See separate topic under Vascular Operations

== Techniques ==

* Exposure
** Plan the incision using pulse and landmarks
** Should be able to expose without transecting muscle
** Ligate and divide lymphatics if necessary
** Dissect in the peri-adventitial plane by holding it and retracting in one direction
** Once the vessel is sufficiently exposed, encircle it with a Silastic loop or umbilical tape
* Control
** Give heparin 5 minutes prior to clamping
** Identify a disease-free segment to clamp - if unable to find a segment with <50% plaque, need to use an alternative
*** Balloon occlusion - Fogarty catheter
*** Vessel loops - ideal for small to medium vessels. Be careful not to put too much tension on the loops. Can use double loop (Potts technique) to minimise surgery
***
*** Tourniquet: good in the extremities. Elevate the leg, wrap it from foot up, inflate the tourniquet to either 250mm Hg or 100mm Hg above SBP. Sometimes doesn't work that well with calcified arteries - can increase the pressure, or separately clamp CFA.

== Thrombectomy and thromboembolectomy ==

** Arteriotomy
*** Arteriotomy can be placed either proximal or distal to the clot
*** Site selection depends on ease of exposure, anticipated location of thrombus, and ease of closure
*** Acute lower extremity ischaemia - CFA
*** Transverse arteriotomy - easier to close (interrupted sutures), generally preferred for dealing with emboli
*** Longitudinal - atherosclerotic/thrombotic process, significant plaque (allows incorporation into an anastomosis in case a bypass is required)
**** Patch needed to close
** Thrombectomy catheter choice
*** Size 2F to 7F 
*** All use saline to inflate except 2F which requires air
*** Standard balloons are made of latex, but are also available latex-free
*** Also come in sizes that can be introduced over guidewires for size 3-7
*** Special corkscrew catheters for adherent clot are available
***

{| class="wikitable"
|Size
|Diameter of fully inflated balloon
|Use
|-
|2
|4mm
|Very small pedal or hand arteries
|-
|3
|5mm
|Tibial vessels
|-
|4
|9mm
|SFA/popliteal arteries
|-
|5
|11mm
|External or common iliac
|-
|6
|13mm
|Aortic or saddle PE
|-
|7
|14mm
|Aortic or saddle PE
|}

*

* Thrombectomy procedure
** Test balloon, and only have enough saline in the syringe to inflate the balloon correctly
** Establish inflow: pass catheter proximally, inflate, withdraw through arteriotomy. Allow brief but unrestricted bleeding to flush debris.
** Pass it gently - don't advance forcefully, can pass into subintimal plane
** Fluoroscopic procedure - essentially the same. Can be quite tricky to get the balloon to the right spot. Can either bend the tip, or put another balloon distally at a junction to prevent it going down that path.
* Complications
** Vascular injury
*** Excessive inflation of balloon - can result in significant shearing, even leading to rupture or pseudoaneurysm
*** During insertion, advancement, or withdrawal

== Endarterectomy ==

* Principles:
** Removal of atherosclerotic plaques that compromise the arterial lumen
** Usually results in removal of the thickened intima and inner media
** Should not be performed in an aneurysmal artery - adventitia too weak
** Need a smooth transition at the endpoint of the endarterectomy plane in the direction of arterial flow
* Techniques
** Open endarterectomy
*** Open the artery longitudinally at the site of disease
*** Plaque separated from the wall in the direction of the arteriotomy
**** Hold the edge of the adventitia with the forceps and pull it away from the plaque
**** Then develop the plane between the plaque and the media or adventitia
**** Develop the plane on both sides and move posteriorly until it becomes circumferential
*** When a normal part of the wall is reached, the plaque either 'feathers out' or is transected flush with the arterial wall without leaving a significant protruding edge (if that is done, need to tack it down with sutures to avoid plaque lifting/dissection/thrombosis)
**** Tack down by putting one end of the suture in the remaining plaque, 1mm distal to the endpoint, and the other end at the junction of the endarterectomy and the endarterectomised surface
**** Some believe that tacking the proximal endpoint is unnecessary because the flow doesn't lift it
** Semiclosed
*** Artery opened in a proximal and distal location
*** Plaque cored out between the two holes
*** Avoids big longitudinal arteriotomy
** Eversion
*** Transect the artery and evert the adventitia
*** Plaque should come straight off
*** Need to expose a long segment of artery
** Orificial
** Extraction

== Arteriotomy closure ==

* Primary closure
** Indications
*** Transverse arteriotomy, even in small arteries down to 2mm diameter
*** Longitudinal incisions where the vessel is not diseased and has a diameter >5mm
*** Primary closure may still be possible with plaque, but interrupted technique is preferred
** Technique
*** Include all layers of the vessel wall
*** Don't allow adventitial fibres to protrude into the lumen - can be thrombogenic
*** Needle should be introduced from intimal side towards adventitial side (if there is plaque, it can be pushed away from vessel wall and create a site for dissection or thrombus formation
*** If closing with interrupted, use double-ended needles and clip them all before tying at the end
*** If closing continuously, needle would be introduced from the adventitial side of one wall, then the intimal side of the other wall
*** Bites should be evenly placed
* Patch closure
** Benefits
*** Allows the needle to be constantly introduced from intimal side
*** Allows adequate purchase without compromising the lumen
** Indications
*** When primary closure is expected to cause significant luminal narrowing
*** Artery <5mm diameter
*** Significant atherosclerotic plaque
*** Jagged arteriortomy
*** Tortuous artery
*** Also consider risk factors that pre-dispose to restenosis 
**** Hyperlipidaemia
**** Smoking
**** Female
**** History of recurrent stenosis
** Technique
*** Select width of patch to accommodate vessel size
*** Simplest way is to place one suture on each side of the apex and run sutures down the sides
****
*** Can also parachute it down, when suturing in a deep location (wet the suture line with saline first to help it slide)

== Closure of a transected vessel ==

* <3mm arteries and venous branches - simple ligature or clip
* 3-5mm vessels - suture ligature
* Larger vessels - running nonabsorbable suture
* Aortic stump - row of horizontal mattress suture followed by a row of continuous suture


== Anastomotic techniques ==

* End-to-side
** Technique
*** Align the vessels without a twist or kink
*** Arteriotomy length not fully defined - some say length should be twice the bypass diameter; others say arteriotomy >2cm. Most often, arteriotomy 1.2-2x the graft diameter is created.
*** Posterior slit in conduit to allow spatulation
*** Anchor technique
**** Place a suture at the heel of the conduit and arteriotomy, which is tied, thus stabilising everything
**** Suturing continued on one side of the heel to the toe, then halfway down the other side
**** The anastomosis is completed by suturing the other end of the heel suture until it meets the previously placed suture
**** Alternative way is to suture down on both sides and tie at the bottom
*** Parachute technique
**** Good in small or deep locations
* End-to-end
** Indications
*** Replacement of an arterial segment
*** Composite bypass is needed
*** Preservation of retrograde or antegrade flow is not needed
** Technique
*** If it's between two small vessels, they must be spatulated
*** Triangulation method:
****

*

*

*

* Side-to-side
** Rare
** Indications:
*** Radiocephalic fistula for haemodialysis
** Usually 6-10mm long
** Need to lie adjacent to each other with minimal tension
** Longitudinal arteriotomy/venotomy where the walls come into direct contact

* Other techniques:
**

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[[Category:Vascular]]