Venous anomalies Flashcards

1
Q

Clinical significance of venous anomalies

A

→ Rarely clinically significant

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2
Q
A
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2
Q

Embryology of venous system: embryonic venous system

A
  • Earliest form of venous return to embryonic heart
    o Paired cardinal venous system: cranial and caudal cardinal veins
    o Join sinus venosus
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3
Q

What forms CrVC? Which parts of the embryologic system regresses

A

o L cranial cardinal vein regresses → anastomosis to R cranial cardinal vein

o R cranial and common cardinal veins remain and enlarge → form CrVC

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4
Q

What forms from L common cardinal vein persists

A

→ form coronary sinus
 Drain coronary circulation

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5
Q

Supracardinal system and species differences

A

o R supracardinal vein form R azygos (Hu, dog, cats, horses)
o Absent in swines and cattles → will have hemiazygos on L side formed by L supracardinal vein
o Azygos (R) or hemiazygos (L) depending on species
 Join proximal segment of corresponding R or L CrVC

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6
Q

Which species normally have L CrVC

A

Rabbits/rats/mice

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7
Q

Which species normally have L azygos

A

Po

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8
Q

Which species normally have R azygos

A

Ca/Fe

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9
Q

Which species normally have R and L azygos

A

Bo

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10
Q

Breed reported for pLCrVC

A

German Shepherds

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11
Q

From which structure coronary sinus is a remnant

A

embryonic L Cr cardinal vein

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12
Q

Features of pLCrVC

A

o Can be single CrVC or both L and R CrVC present
o Can be associated with other congenital diseases (TOF, ASD, mitral atresia, juxtaposition of RA appendage)
o Should not be ligated → appropriately return venous blood to RA
 Not clinically significant hemodynamically
o Size is iα to co existent R CrVC

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13
Q

Types of pLCrVC described by buchanan

A

o Complete → enter CS
 Receive blood from veins cranial to the heart
o Incomplete → L azygos drain into it before entering CS
 Proximal portion of L CrVC receives vein draining the costocervical-vertebral trunk

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14
Q

In Hu, pLCrVC can be associated w/

A

unroofed CS
 If so, persistent L CrVC drain into LA
 R to L shunting → cyanosis

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15
Q

Anatomy

A

o Starts at jct of L jugular and subclavian vein
o Penetrates pericardium → follow posterior wall of LA to CS

16
Q

Where does pLCrVR empty

A

coronary sinus
o Enters RA in caudodorsal part
o CS normally receive blood from vein of Marshall + coronaries

17
Q

Angio

A

injection of contrast in L jugular vein → enters heart in caudodorsal RA → RV → PA

18
Q
  • Clinical importance
A

o L thoracic exploration → may interfere with surgical exposure
 Especially for PRAA correction: L CrVC will cross over and can obscure ligamentum arteriosum
o Cardiac KT of L jugular vein → unexpected direction
 Harder to get into RV
o No known functional significances

19
Q

Echo

A

o Dilated coronary sinus
 Significant of ↑ coronary sinus blood flow
* Persistent L CrVC
* Total anomalous pulmonary venous connection to CS
* Infrahepatic interruption of CaVC with L azygos continuation
o Persistent L CrVC may be visualized in its course behind LA to RA

20
Q

Contrast echo study

A

agitated saline into cranial vein visible into CS
 R cephalic injection:
* See in RA = normal = confirm R Cr VC present
* See in CS = abnormal = no R Cr VC
 L cephalic injection
* See in RA = no persistent L CrVC = normal
* See in CS = confirm L CrVC
 L saphenous
* See in CS = L azygous

21
Q

Necropsy findings

A

o Size varies (diameters of LCrVC and LIV vary inversely)
o Starts at junction of L jugular and L subclavian veins descending in front of Ao arch → penetrating the pericardium and following posterior wall of LA to CS
o Leads to CS enlargement and posterior displacement on RA floor

22
Q

significance of a left azygous vein

A
  • Present normally in some species
    o Absent in dogs/cats
    o Cow/pig: large L azygos, absent or ↓ R azygos
    o Sheep: equal size R and L azygos
23
Q

L azygos is a remnant of which structure

A

L supracardinal system

24
Q

Where does is enter the heart

A

coronary sinus
 Normally atrophies and become ligament of Marschall

25
Q

How does CaVC develop

A

anastomosis of 3 paired segments
 Caudal cardinal vein
 Subcardinal vein
 Supracardinal vein

26
Q

What is the course of normal R azygos vein

A

o Course on the R ventrolateral aspect of thoracic vertebral bodies
o Turn ventrally around root of R lung
o Empties at right angle into termination of CrVC
o Receives intercostal veins from 5th IC space to 2nd or 3rd lumbar vertebrae

27
Q

Features of L azygos vein

A
  • Occasionally sole source of caudal venous return if concurrent interruption of CaVC
28
Q

CTX L azygos vein

A

o Enlarged Ao arch
o Unusual vascular structure at heart base
 More caudally then expected Ao arch

29
Q

L azygos vein angio

A

contrast injection in L saphenous vein
o Large opacified caudal vein course toward heart
 // to descending Ao
 Positioned where usual azygos vein in pigs and ruminants
o Extended ventrocranial → tracheal bifurcation → curved caudally

30
Q

L azygos vein AUS

A

small CaVC

31
Q

L azygos vein echo

A

normal heart size and function
o Dilated coronary sinus on SAX and LAX R parasternal views
o L azygos vein visible

32
Q

L azygos vein contrast study

A

injection of microbubbles into L saphenous vein → bubbles visible into CS