Editing Fem-pop occlusive disease


== Aetiology ==

* Atherosclerosis (vast majority)
* Fibromuscular dysplasia
* Inflammatory arteridites
* Entrapment syndromes
* Cystic adventitial disease
* Congenital vascular anomalies
* Chronic compartment syndromes

== Risk factors ==

* The usual

== Diagnostic evaluation ==

* Asymptomatic
* Intermittent claudication
* Critical limb ischaemia
** Ischaemic rest pain (forefoot pain at rest)
** Ulceration on distal toes/bony prominences
*** Look for arterial-type ulcers
** Gangrene
* ABI (ankle systolic pressure in each leg divided by the highest brachial artery systolic pressure
** Normal 0.9-1.1
** <0.9 with a compatible history is diagnostic of arterial occlusive disease (sensitivity of 95% in identifying angiographically confirmed PAD)
** Claudication ABI is typically 0.4 - 0.9
** Rest pain or tissue loss ABI is typically <0.4
** ABI > 1.1 probably reflects calcified arteries (diabetes, ESRF)
*** Need to use arterial waveforms, toe waveforms/Doppler pressures, and transcutaneous oxygen sats in this case
** Claudicants with single-level stenosis may only show a reduced ABI after exercise
*** >20% reduction post-exercise is abnormal

== Management ==

=== Indication for intervention: ===

* Limb-threatening ischaemia
* Lifestyle-limiting IC


Type A and B: endovascular first

Type C: case by case

Type D: surgery first-line

Ongoing BEST-CLI trial attempting to give a better optimal treatment strategy


=== Medical treatment ===

* Smoking cessation
* Weight loss
* Antiplatelets
* Treat:
** HTN
** Hyperlipidaemia
** Diabetes
* Exercise programs - 3x weekly, 30-45 mins
* Phosphodiesterase inhibitors may improve claudication pain

=== Endovascular approach ===

# Establish arterial access
#* Generally contralateral CFA
# Diagnostic arteriogram
# Identifying culprit lesion
# Successful traversal of the lesion
# Balloon angioplasty +/- stent (if suboptimal angioplasty result)
# Completion arteriogram
# Closure of arterial access site

=== Surgical treatment ===

* Factors required for bypass
** Adequate inflow site
*** Choice based on examination/USS, but needs to be confirmed with angio
*** Address haemodynamically-significant lesions prior to bypass
*** Most common choice in fem-pop bypass is CFA
**** If significantly diseased, consider CFA endarterectomy
*** PFA or SFA are alternative inflow sources
** Adequate outflow site
*** Ideally: normal in calibre, free of stenosis, in continuity with at least one of the arteries supplying the foot
*** Below-knee popliteal is best. If that's occluded, best bet is tibial artery with best foot runoff
*** Can consider ulcer locations sometimes (angiosome theory)
** Adequate conduit (best is great saphenous vein - no sclerosis, at least 3mm in diameter)
*** Vein mapping - diameter, compressibility, wall thickness, flow
*** GSV preferred, otherwise use cephalic/basilic/small saphenous
*** GSV should be reversed, but can also be done in situ
*** Prosthetic is last resort - PTFE. Improved patency rates by using an adjunctive vein cuff (Miller or St Mary's) or Taylor patch
***
* If these are not present, endarterectomy/profundoplasty might be a better alternative
* Surgery remains best option for patients with ischaemic rest pain or tissue loss.

=== Fem-pop bypass graft ===

* PFA supplies blood to thigh, SFA to leg via adductor canal
* SFA enters popliteal fossa at apex, where it becomes POPA
* CFV just medial to CFA in fem triangle, with GSV entering the CSV at fossa ovalis, and lymphatics medial to that.
** Note PFA generally posterolateral branch of CFA
*
* Below-knee POPA is variable in length before dividing into ATA (which travels laterally, enters anterior compartment, becomes DP) and TPT (branches into peroneal and PT, and enters deep posterior compartment)

GSV HARVEST

* Identify GSV in fem triangle. Incise directly over vein to avoid undermining. 
* Dissect periadventitial tissue away sharply. Ligate tributaries with silk (leave a short stump, don't narrow the conduit)
* Continue dissection distally until adequate length is obtained
* Place small clamp flush with GSV. Divide. Oversew stump with running monofilament.
* Preparation
** Place in a bath of heparinised saline and papaverine
** Clamp proximal end with small bulldog
** Flush heparinised saline from distal end
** Meticulously repair small tears
* Store in chilled, heparinised blood until ready to use

SSV HARVEST

* Best with patient prone
* Longitudinal incision posterior calf lateral to Achilles tendon
* Beware of sural nerve

SPLICING VEINS

* Spatulate
* Interrupted fine polypropylene sutures

FEM TO ABOVE KNEE POP BG

* Incision directly over CFA pulse and dissect down to femoral sheath, use self-retainers
** Expose CFA proximally to inguinal ligament
** Continue dissection distally to proximal SFA
** Identify and expose PFA
* AKP exposed from medial thigh - longitudinal incision anterior to sartorius and retract sartorius posterolaterally
* Divide deep fascia to expose popliteal fossa. Dissect and mobilise artery.
* Identify a healthy section of artery and place proximal and distal clamps
* Tunnel conduit - put clamps from groin to popliteal fossa in anatomical plane, and pull vein through
* Proximal anastamosis first, then distal

TO BELOW-KNEE POP

* Longitudinal incision 1-2cm posterior to medial edge of tibia
* Divide pes anserinus
* Mobilise medial head of gastrocnemius - expose pop fossa
* Dissect pop vein away from artery
* Anastamosis

INTRA-OP BYPASS GRAFT ASSESSMENT

* Confirm graft patency
* Establish integrity of conduit
* Confirm adequacy of outflow
* Identify potential conduit, anastomotic, technical defects that may predispose to thrombosis
* Doppler foot

WOUND CLOSURE

* Layers
* Skin edge eversion w/ nylon
* Drain in groin if concern for lymphatic leak

== Complications ==

* Early graft thrombosis (5%)
** Often results from technical error/poor conduit/poor outflow
** Needs return to theatre
* Late graft thrombosis (>30 days)
** Intimal hyperplasia
* Bleeding (0.4%)
** Bleeding of vein graft can be repaired with direct cut-down onto vein
* Infection
** Deep infections require aggressive debridement
* Lymphatic leak
* Compartment syndrome



== Graft surveillance ==

* USS at 1/12, then three-monthly for a year, then six-monthly for two years, then annually
** Evidence of impending failure:
*** Focal elevated peak systolic velocity >300cm/s
*** Peak systolic velocity ratio of 3 to 4 (ratio of flow at the lesion to flow proximal)
*** Low-flow velocities through the graft (<40cm/s)
*** A drop in the ABI of 0.15 or more from the previous study
** Intervention can endovascular or via open revision

[[Category:Vascular]]