Chapter 163 - Congenital occlusion/absence IVC

Question 1

Incidence of absence IVC (AIVC)

Answer 1

0.3-0.5%

Question 2

% of people under 30 with DVT that have AIVC

Answer 2

5%

Question 3

When does AIVC usually happen at what age

Answer 3

2nd decade of life

Question 4

Pathogenesis of AIVC causing DVT

Answer 4

low flow state + second hit (thrombophilia, other usual risks for DVT)

Question 5

Association of AIVC with other congenital problems

Answer 5

1) Atrial septal defect
2) polysplenia
3) dysgenesis of lungs

Question 6

Embryology of IVC

Answer 6

3 primitive veins form collaterals and connect via auto anastomosis

1) supracardinal
2) subcardinal
3) postcardinal

Question 7

IVC segments and its embryologic origin

Answer 7

1) hepatic - hepatic sinusoids
2) prerenal - subcardinal
3) post renal - supracardinal
4) renal collar - subcardinal and postcardinal

azygous/hemiazygous - supracardinal

Question 8

IVC anomaly types and embryologic cause

Answer 8

1) isolated left IVC: regression of right supracardinal with persistent left supracardinal
2) double IVC: both left and right supracardinal veins persist
3) segment or total atresia: failure of one or multiple segment anastomosis

Question 9

Presentation of AIVC

Answer 9

1) incidental

2) DVT

Question 10

Diagnosis of AIVC

Answer 10

1) clinical
2) duplex
3) axial imaging (CT/MRI)
4) conventional venogram

Question 11

Duplex signs of AIVC

Answer 11

1) lack of respiratory phasity
2) signs of chronic DVT on usual US
3) lots of collaterals
4) direct insonation of iliocaval veins

Question 12

Disadvantages of US for AIVC

Answer 12

1) operator dependent

2) patient factors: size, gas, cooperation

Question 13

Axial imaging for AIVC pro of each

Answer 13

Both: anatomic characterization
CT: faster, better size resolution
MRI: time resolution better, no contrast needed

Question 14

Venography in AIVC

Answer 14

1) real-time
2) intervene at the same time
3) anatomy deneation

Question 15

Treatment of AIVC

Answer 15

Indication: symptom driven, not for prevention of PE
Compression + AC (lifelong)
Thrombolysis within 2-4 weeks
Surgery

Question 16

CAVENT trial

Answer 16

1) anticoagulation vs tpa in iliofem DVT
2) better patency 47 vs 66% at 5 years in tpa
3) better freedom from PTS 41 vs 55% with tpa

Question 17

tpa risk of bleeding

Answer 17

5-10%

Question 18

In severe DVT should add this therapy

Answer 18

pharmacomechanical thrombectomy

faster restoration of flow

Question 19

In refractory DVT from tpa need

Answer 19

Open reconstruction; stenting unlikely useful in AIVC

1) autologous or homograft
2) prosthetic needs lifelong anticoagulation
3) fistula not needed and can cause high output cardiac failure

Question 20

Goal of treatment in AIVC

Answer 20

Restore previous venous collaterals with tpa and long term anticoagulation