Chapter 161 - iliocaval obstruction - endovascular Flashcards
Sensitivity of venography to identify May Thurner
50%
Sensitivity of IVUS to identify May Thurner
80%
Rate of right CIA compressing left CIV in general population
2/3
Areas of non-thrombotic iliac vein lesions
Proximal left - CIV by R CIA
Proximal right - CIV by R CIA
Distal left - EIV by L IIA
Distal right - EIV by R CIA
Inguinal ligament also a source
Two types of iliac caval venous obstruction
1) NIVL non-thrombotic iliac vein lesion (May Thurner)
2) Post-thrombotic iliac vein stenosis (PTS)
Rokitansky stenosis
Post-thrombotic fibrous envelop with diffuse long stenosis
NIVL vs PTS diference
NIVL focal and segmental
PTS continuous and longer
Rate of venographic collaterals in iliac vein stenosis
30%
Geometric factor to determine resistance
r^4/L Poisseuille equation
rate of lymphatic dysfunction in chronic venous disease
30%
Rate of lymphatic dysfunction normalization after iliac stenting of vein
25%
Gold standard for diagnosing iliac vein lesions
IVUS
need to use concurrently with venography because venography can be highly inaccurate
Pancaking on venography
Flattened appearance of CIV when it is compressed giving the false sense of the iliac confluence when in reality it’s much higher
Iliocaval stenting technique
1) Access mid thigh FV
2) 11Fr sheath for ease of manipulation
3) venogram for mapping otherwise IVUS only
4) stent liberally
5) predilatation often necessary
Optimal iliofemoral venous segment diameter
CFV 12 mm
EIV 14 mm
CIV 16 mm
IVC 17-24 mm
Stenting of proximal CIV lesion specific stent use
18 or 20 mm Wallsent dilated to 16 or 18 mm
Reinforce with Z stent within Wallstent to add radial strength but not encroach on contralateral side
Success of crossing CTO venous lesions in iliac and IVC
85%
When crossing IVC CTO, passage of wire in the midline is a clue for
Vertebral canal entry
need to pull back
Time of venous endothelial healing
6 weeks after injury
Anticoagulation protocol with venous stent
LMWH for 48 hours
ASA daily after
AC if
1) thrombophilia
2) recurrent thrombosis
3) previous unprovoked thrombosis
4) extensive stenting
Rate of acute thrombosis of venous stent < 30 days
1%
Late occlusion of stents > 30 days in venous stenting
3.5%
most 87% in PTS
Reasons for venous stent failure
1) inflow or outflow lesions
2) inadequately covered stenting
3) undersizing stent
4) stent compression (external)
5) in-stent restenosis
In stent restenosis time
< 30 days
due to thrombus (soft ISR)
after few months hard ISR
High pressure balloon definition
14-16 atm
Stenting surveillance
Duplex POD1
Duplex 4-6 weeks
Duplex 3-6 months
Access complication of deep venous access for stenting
0.4%
DVT incidence after deep venous stenting
3% in 22 months
Patency of venous stenting with NIVL vs PTS lesions
NIVL 79-100%
PTS 57-86%
6 years
Rate of ulcer healing after venous stenting
NIVL 87%
PTS 66%
5 years
Special population that benefit from venous stenting where compression is difficult
1) elterly
2) obese
3) secondary lymphedema
Rate of secondary venous lymphedema in CVD
16-30%
Recanalizing IVC filter occlusion patency
86% 5 years
