Topic 11 CVIs

Question 1

Describe the structure of veins

Answer 1

Veins have an adventitia, media and intima. The thickness of the media and adventitia is reduced in the vein compared to an artery. Veins joint together at a confluence and the veins which join together are tributaries of the vein which they join into

Question 2

What are the two types of valves

Answer 2

Ostial and parietal

Question 3

What are ostial valves?

Answer 3

Ostial valves occur at the confluence of tributaries as they drain into deep veins or main superficial veins, but prevent backflow into the tributary

Question 4

What are parietal valves?

Answer 4

Parietal valves form in vein segments between the tributaries and are typically bicuspid or tricuspid in the lower limb. They prevent extended back-flow or reflux of blood following augmentation of calf muscle pumps.

Question 5

What causes CVD?

Answer 5

CVD may be related to inflammatory changes in the vein wall such as inflammation, fibrosis, loss of smooth muscle function and the destruction of venous valves. The primary cause of varicose veins is unknown. Haemodynamics or valvular failure may be the primary mechanism which results in CVD, however, this can only happen if there is pathology of the vein wall and valve.

Question 6

What happens to venous pressure while supine?

Answer 6

Without gravity, venous flow is generated by the pressure difference between the heart and the periphery. This assumes no muscle movement or external causes for changing venous flow

Question 7

What happens to venous pressure while standing?

Answer 7

Gravity begins to increase the pressure in the veins in the direction opposite to that or normal venous flow direction. gravity produces a force on the venous blood in the standing position which is related to the height and viscosity of blood.

Question 8

How do venous valves affect venous pressure?

Answer 8

Vlaves are fine membranes and do not influence the transmission of pressure from the heart to the foot.
Valves do not resist or absorb any significant amount of force produced by venous column of blood.
Valves prevent blood from returning to the foot.

Question 9

What are risk factors of varicose veins?

Answer 9

• young and female
• old and male
• family history of varicose veins
• giving birth to more than 3 children
• previous DVT

Question 10

What are symptoms of CVD?

Answer 10

• skin pigmentation
• itching
• weeping dermatitis
• swelling
• heaviness in leg
• aching
• lipodermatosclerosis

Question 11

Describe non surgical treatment of CVD

Answer 11

• use of compression bandages and stockings

- venoactive drugs

Question 12

Describe surgical treatment of CVD

Answer 12

• direct surgical disruption of incompetent veins

- ablation with chemical, thermal, laser or mechanical devices

Question 13

What is reflux?

Answer 13

Reflux is an abnormal backflow or retrograde flow of blood in a given vein. Normal veins will show a degree of backflow after augmentation, however significant reflex is that lasting longer than 0.5s in superficial veins and 1s in the deep system

Question 14

What is an incompetent perforating vein?

Answer 14

Incompetent perforating veins allow outward flow to the superficial veins following the release of augmentation below the level of the perforating vein. Some perforators are valveless. The presence of incompetent perforators is important for treating surgeons to consider, as they can play a significant role in recurrent varicose veins by contributed a significant paht for refluxed blood or to form a communication between recurrent varices and deep veins.

Question 15

What is post-thrombotic syndrome?

Answer 15

Post thrombotic syndrome is a syndrome of CVI or DVT due to valvular incompetence which results in chronic reflex and venous hypertension.

Question 16

Why does post-thrombotic syndrome occur?

Answer 16

Incomplete resolution of the clot or inadequate revascularization will promote the formation of collateral veins to bypass the obstructed venous segment. Collateral pathways may be formed, and in cases were these pathways cannot drain the limb effectively, venous pressure will increase below the level of obstruction. Over time, this leads to chronic limb swelling and skin changes. In severe cases, this will impair capillary flow and cause ischaemia and venous gangrene.

Question 17

List some severe complications of CVD

Answer 17

• ulceration

- liposclerosis

Question 18

What is pelvic congestion syndrome?

Answer 18

Pelvic congestion syndrome is caused by ovarian vein reflux. It is a cause of chronic pelvic pain. Vulval or peri-vulval varices are frequently associated with pelvic congestion syndrome and can be associated with ovarian vein incompetence. Ovarian veins reflux through the veins of the broad ligament to the vulval tributaries and communicate with recurrent or primary varicosities of the leg

Question 19

What is the purpose of an ovarian vein reflux study?

Answer 19

To establish whether there is any deep reflux pattern in the lower abdomen that may be supplying reflux to vulval varicosities with the view for intervention

Question 20

How are ovarian veins studied?

Answer 20

The patient is in a supine position, fasted. Images of the para-ovarian and para-uterine veins are taken. The right and left ovarian veins, left renal vein and right and left internal iliac veins are also assessed. The diameter of the largest, reproducible veins are measured. The patient is then raised 60 degrees and the veins that were noted supine and re-measured.

Question 21

How do you demonstrate reflux on ovarian veins?

Answer 21

• valsalva
• leg augmentation
• abdominal distension

However, reflux should be evident without these maneuvers