Chapter 161 - iliocaval obstruction - endovascular

Question 1

Sensitivity of venography to identify May Thurner

Answer 1

50%

Question 2

Sensitivity of IVUS to identify May Thurner

Answer 2

80%

Question 3

Rate of right CIA compressing left CIV in general population

Answer 3

2/3

Question 4

Areas of non-thrombotic iliac vein lesions

Answer 4

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

Question 5

Two types of iliac caval venous obstruction

Answer 5

1) NIVL non-thrombotic iliac vein lesion (May Thurner)

2) Post-thrombotic iliac vein stenosis (PTS)

Question 6

Rokitansky stenosis

Answer 6

Post-thrombotic fibrous envelop with diffuse long stenosis

Question 7

NIVL vs PTS diference

Answer 7

NIVL focal and segmental

PTS continuous and longer

Question 8

Rate of venographic collaterals in iliac vein stenosis

Answer 8

30%

Question 9

Geometric factor to determine resistance

Answer 9

r^4/L Poisseuille equation

Question 10

rate of lymphatic dysfunction in chronic venous disease

Answer 10

30%

Question 11

Rate of lymphatic dysfunction normalization after iliac stenting of vein

Answer 11

25%

Question 12

Gold standard for diagnosing iliac vein lesions

Answer 12

IVUS

need to use concurrently with venography because venography can be highly inaccurate

Question 13

Pancaking on venography

Answer 13

Flattened appearance of CIV when it is compressed giving the false sense of the iliac confluence when in reality it’s much higher

Question 14

Iliocaval stenting technique

Answer 14

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

Question 15

Optimal iliofemoral venous segment diameter

Answer 15

CFV 12 mm
EIV 14 mm
CIV 16 mm
IVC 17-24 mm

Question 16

Stenting of proximal CIV lesion specific stent use

Answer 16

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

Question 17

Success of crossing CTO venous lesions in iliac and IVC

Answer 17

85%

Question 18

When crossing IVC CTO, passage of wire in the midline is a clue for

Answer 18

Vertebral canal entry

need to pull back

Question 19

Time of venous endothelial healing

Answer 19

6 weeks after injury

Question 20

Anticoagulation protocol with venous stent

Answer 20

LMWH for 48 hours
ASA daily after

AC if

1) thrombophilia
2) recurrent thrombosis
3) previous unprovoked thrombosis
4) extensive stenting

Question 21

Rate of acute thrombosis of venous stent < 30 days

Answer 21

1%

Question 22

Late occlusion of stents > 30 days in venous stenting

Answer 22

3.5%

most 87% in PTS

Question 23

Reasons for venous stent failure

Answer 23

1) inflow or outflow lesions
2) inadequately covered stenting
3) undersizing stent
4) stent compression (external)
5) in-stent restenosis

Question 24

In stent restenosis time

Answer 24

< 30 days
due to thrombus (soft ISR)

after few months hard ISR

Question 25

High pressure balloon definition

Answer 25

14-16 atm

Question 26

Stenting surveillance

Answer 26

Duplex POD1
Duplex 4-6 weeks
Duplex 3-6 months

Question 27

Access complication of deep venous access for stenting

Answer 27

0.4%

Question 28

DVT incidence after deep venous stenting

Answer 28

3% in 22 months

Question 29

Patency of venous stenting with NIVL vs PTS lesions

Answer 29

NIVL 79-100%
PTS 57-86%

6 years

Question 30

Rate of ulcer healing after venous stenting

Answer 30

NIVL 87%
PTS 66%

5 years

Question 31

Special population that benefit from venous stenting where compression is difficult

Answer 31

1) elterly
2) obese
3) secondary lymphedema

Question 32

Rate of secondary venous lymphedema in CVD

Answer 32

16-30%

Question 33

Recanalizing IVC filter occlusion patency

Answer 33

86% 5 years