Arterial.10.AV fistula Flashcards
Definition of AV fistula
Communication between an artery and vein
PATHOLOGICAL TYPES of AV fistula
- Aneurysmal varix
2. Varicose aneurysm
Aneurysmal varix in PATHOLOGICAL TYPES of AV fistula
Direct communication between an artery & vein.
Varicose aneurysm in PATHOLOGICAL TYPES of AV fistula
The artery & vein communicate through a false sac.
Etiology of AV fistula
A. Congenital
B. Acquired
Congenital Etiology of AV fistula
- Robertson’s Giant Limb
2. Cirsoid aneurysm of the scalp “Arterial hemangioma”
Robertson’s Giant Limb in Congenital Etiology of AV fistula
- Alternative name
* Pathogenesis
Alternative name of Robertson’s Giant Limb in Congenital Etiology of AV fistula
Klippel-Trenaunay syndrome
Pathogenesis of Robertson’s Giant Limb in Congenital Etiology of AV fistula
- Affecting mainly the lower limb with multiple A.V fistula mainly in the bones
- Causing local gigantism
Cirsoid aneurysm of the scalp in Congenital Etiology of AV fistula
- Alternative name
- Common sites
- Associations
Alternative name of Cirsoid aneurysm of the scalp in Congenital Etiology of AV fistula
Arterial hemangioma
Common sites of Cirsoid aneurysm of the scalp in Congenital Etiology of AV fistula
- Temporal region : in relation to the superficial temporal artery
- Occipital regions of the scalp.
Associations of Cirsoid aneurysm of the scalp in Congenital Etiology of AV fistula
Sometimes it has intracranial connections
Clinical picture of AV fistula
A) Local characters
B) Effects on the Limb
C) Effects on the circulation
Local characters in Clinical picture of AV fistula
- Similarities to true aneurysm If there is a swelling
* Differences between Varicose aneurysm and true aneurysm
Similarities to true aneurysm If there is a swelling in Local characters in Clinical picture of AV fistula
- Smooth, rounded, cystic & compressible with expansile pulsation
- In the line of an artery.
- Movable across, but not along that artery
- Compressing the proximal artery reduces its size and stops its pulsation, thrill and bruit.
Differences between Varicose aneurysm and true aneurysm in Local characters in Clinical picture of AV fistula
- Timing of thrill and bruit
* Propagation of thrill and bruit
Timing of thrill and bruit in Varicose aneurysm
Overlying systolic & diastolic
Timing of thrill and bruit in true aneurysm
Overlying only systolic
Propagation of thrill and bruit in Varicose aneurysm
propagated distally and proximally.
Propagation of thrill and bruit in true aneurysm
propagated distally only.
Effects on the Iimb in Clinical picture of AV fistula
- Local overgrowth (gigantism)
- Chronic ischemia
- Pulsatile varicose veins
Local overgrowth (gigantism) in Effects on the Iimb in Clinical picture of AV fistula
- Affected type of AV fistula
* Pathogenesis
Affected type of AV fistula in Local overgrowth (gigantism) in Effects on the Iimb in Clinical picture of AV fistula
only in congenital type especially if widespread.
Pathogenesis of Local overgrowth (gigantism) in Effects on the Iimb in Clinical picture of AV fistula
It is due to increase oxygenation and nutrition through the leg.
Pathogenesis of Chronic ischemia in Effects on the Iimb in Clinical picture of AV fistula
due to decrease arterial blood flow.
Pathogenesis of Pulsatile varicose veins in Effects on the Iimb in Clinical picture of AV fistula
due to increase venous flow.
Effects of AV fistula on the circulation in Clinical picture of AV fistula
- Hyperdynamic circulation
- The Branham’s bradycardic reaction :
- Later ventricular hypertrophy & high cardiac output failure occur.
Pathogenesis of Hyperdynamic circulation in Effects of AV fistula on the circulation in Clinical picture of AV fistula
A-V fistula produces :
- Increased venous return.
- Increased cardiac output.
- Tachycardia & high pulse pressure.
The Branham’s bradycardic reaction in Effects of AV fistula on the circulation in Clinical picture of AV fistula
Compressing the artery proximal to the fistula causes bradycardia (Branham’s sign).
due to Dec venous return to the heart
INVESTIGATIONS OF AV fistula
- ACQUIRED FISTULA
* CIRSOID ANEURYSM OF THE SCALP
ACQUIRED FISTULA investigation in INVESTIGATIONS OF AV fistula
- Doppler study or duplex scan
2. Arteriography.
Doppler study or duplex in ACQUIRED FISTULA INVESTIGATIONS OF AV fistula
can localize the site of the fistula.
CIRSOID ANEURYSM OF THE SCALP investigations in INVESTIGATIONS OF AV fistula
- Plain X-Ray skull
2. External carotid angiography
Plain X-Ray skull in CIRSOID ANEURYSM OF THE SCALP investigations in INVESTIGATIONS OF AV fistula
Rarified bone.
External carotid angiography in CIRSOID ANEURYSM OF THE SCALP investigations in INVESTIGATIONS OF AV fistula
To detect any intracranial connections
Treatment of AV fistula
- Congenital AV fistula
* Acquired AV fistula
Congenital AV fistula Treatment in Treatment of AV fistula
- Robertson’s Giant Limb
2. Cirsoid aneurysm
Treatment of Robertson’s Giant Limb in Congenital AV fistula Treatment in Treatment of AV fistula
Usually stationary & needs no operative interference.
Treatment of Cirsoid aneurysm in Congenital AV fistula Treatment in Treatment of AV fistula
- Surgical excision under general hypotensive anesthesia
* Preliminary therapeutic embolization by gelfoam of the feeding vessels may be tried.
Acquired AV fistula Treatment in Treatment of AV fistula
- Excision and vascular repair of both artery & vein.
2. Quadruple ligation
Quadruple ligation in Acquired AV fistula Treatment in Treatment of AV fistula
The artery & vein are ligated above & below the fistula
Done if the above operation is difficult due to extensive adhesions in a peripheral unimportant artery.
