Aneurysms and Arterio-venous Fistula - PDF

This topic is under the Chapter - Arterial Disorders. The MBBS Students should know the types of Aneurysms and particularly Abdominal Aortic Aneurysms.

1. Prof. U. Murali.
Aneurysms &
A V F

2. Learning Objectives
◼Define Aneurysm. / List the types & causes of Aneurysm.
◼Discuss the C/F, investigations, complications & treatment of
Aneurysm.
◼Describe the etio-pathology & C/F of Abdominal Aortic Aneurysm.
◼Outline the investigations & treatment of AAA.
◼Explain about Arterio-venous fistula.

3. Aneurysm
Prof. U.Murali.

4. Aneurysm –Definition
◼An aneurysm is a permanent,
localized, abnormal dilation
of a blood vessel occurring
due to congenital (or)
acquired weakening (or)
destruction of the vessel wall.
◼Diameter will be 50% more
than expectednormal
diameter of that artery in
aneurysm.

5. Types of Aneurysms
1. Composition of vessel wall
◼True Aneurysm –
When all the 3 normal layers of
the blood vessel are involved -
intact.
◼False Aneurysm –
When only fibrous tissue forms
the wall of the sac and the rest of
the layers are damaged due to
trauma.

6. Types of Aneurysms
2. Shape of Aneurysms
◼Fusiform –
Uniform dilatation of entire
circumference of arterial wall.
◼Saccular –
Dilatation of part of circumference of
the arterial wall.
◼Dissecting –
Through a tear in the intima blood
dissects between inner & outer part
of tunica media of the artery.

7. Types of Aneurysms
3. Etiology & Pathogenic
◼Atheromatous
◼Mycotic (bacterial rather than
fungal)
◼Syphilitic
◼Collagen disease
◼Traumatic
◼Berry
◼Dissecting

8. Aetiology / Causes
Acquired Congenital
Degenerative–Atherosclerosis / Mucoiddegeneration
Traumatic–Direct / Indirect –Cervical rib / Irradiation
Infective–Syphilitic / Mycotic / TB
Collagen diseases –Marfan’s / PAN
Berry aneurysm
Cirsoidaneurysm
Cong. AVF

9. Sites & D / D
◼Aorta.
◼Femoral.
◼Popliteal.
◼Subclavian.
◼Cerebral, mesenteric,
renal, splenic arteries.
◼Pyogenic abscess
◼Vascular tumours.
◼Pulsating tumours.
◼Pseudocyst of pancreas
mimics aortic aneurysm.
◼AV fistula.

10. Clinical Features
◼Swelling at the site which is pulsatile
(expansile), smooth, soft, warm,
compressible, with thrillon palpation and
bruiton auscultation.
◼Distal oedema due to venouscompression.
◼Altered sensation due to compression of
nerves.
◼Erosion into bones, joints, trachea (or)
oesophagus.
◼Aneurysm with thrombosis can throw an
emboluscausing gangrene of toes, digits,
extending often proximally also.

11. Investigations
◼Doppler / Duplex scan
◼Angiogram –DSA
◼U/S │CT -scan
◼X-ray
◼Tests relevant –cause

12. Complications
◼Thrombosisand distal ischemia
◼Release of embolicausing acute
arterial occlusion
◼Pressure effects on bone
(erosion); skin; veins (oedema);
nerves (pain, paraesthesia);
stomach (erosion—
haematemesis); oesophagus
(dysphagia)
◼Rupture
◼Infectionof aneurysm

13. Treatment
◼Reconstruction of artery using
arterial grafts.
◼Arterial endoaneurysmorrhaphy—
MATAS.
◼Therapeutic embolization.
◼Clippingthe vessel under guidance
(e.g. cranial aneurysms).

14. A AA
Prof. U.Murali.

15. Abdominal Aortic Aneurysm (AAA)
◼It is the most common aortic aneurysm.
◼Splenic artery aneurysm is the 2nd most
common type.
◼Incidence is 2%. It is more common in
males.
◼Transverse diameter of aorta in an
aneurysm should be 3 cm or more.
◼Common in elderly; chance of getting
aneurysm in genetically related first
degreerelatives is 10 times more.
◼Common in smokers / in 55% of patients
Chlamydia pneumoniaeis identified.

16. A A A –Causes
◼Atherosclerosis (95%) –the most
common cause.
◼Familialaortic aneurysm
(associated with 25% of AAA) is
more prevalent in females.
Marfan’s, EhlerDanlossyndromes
are related genetically.
◼Others:Syphilis, dissection,
trauma, collagen diseases,
infection, arteritis, cystic medial
necrosis, association with
Chlamydia pneumoniae(55%).

17. Classification –A A A
◼Infra-renal—most
common 95%.
◼Suprarenal—5%.
Isolated suprarenal type is
rare; it is usually
associated with thoracic
and (or) infra-renal types.
◼Asymptomatic.
◼Symptomatic.
◼Symptomatic ruptured
III

18. A A A -Asymptomatic
◼It is found incidentallyeither on
clinical exam.(or) on angio/ U/S.
◼It is identifiedduring routine abd.
palpation (or) while assessing (or)
operating for some other abd.
conditions.
◼Repair is required if diameter is
over 5.5 cm on ultrasound.

19. A A A –Symptomatic i/o Rupture
◼Presents as back pain, abd. pain, mass
abdomenwhich is smooth, soft, non-
mobile, not moving with respiration,
vertically placed above the umbilical level,
pulsatileboth in supine as well as knee-
elbow position with same intensity,
resonanton percussion.
◼GIT, urinary, venous symptoms can also
occur.
◼Pain may also occur in the thigh and groin
because of nerve compression.
◼Lower limb ischemia and embolic
episodescan occur.

20. A A A -Investigations
◼FBC / LP / RBS / RFT / CT
◼B. grouping & X –matching
◼X-ray chest / ECG / ECHO
◼U/S –abd / CT –scan
◼CT / MR -Angiogram
◼Other relevant –cause

21. A A A –Complications │ D / D
◼Rupture, infection
◼Thrombosis, embolism
◼Distal ischaemia / gangrene
◼Aorto-cavalfistula formation
◼Aorto-enteric fistula
◼Erosion of vertebra
◼Spinal cord ischaemia when
thrombosis develops
◼Retroperitoneal mass
◼Pseudocystof pancreas
◼Retroperitoneal cyst
◼Mesenteric ischaemia
◼Acute pancreatitis
◼PDU
◼Others –disc prolapse /
sciatica

22. A A A -Treatment
MEDICAL SURGICAL INDICATIONS
◼In Low-risk –size < 5 cm.
◼Risk factor –Modifications.
◼Periodic measurement of
the size of aneurysm.
◼Asymptomatic aneurysm > 5.5 cm.
◼Growth rate more than 0.5 cm/year.
◼Painful, tender aneurysm.
◼Thrombosed aneurysm, aneurysm
with distal emboli.

23. Surgical TRT –Methods
◼Endo-aneurysmorrhaphy
with intraluminal graft
◼Endovascular aneurysm repair
(EVAR)
◼Minimal incision aortic surgery
(MIAS)

28. A A A –Symptomatic i Rupture
◼Risk of rupture is 1%, if dia.
within 5.5 cm Risk ↑ to 20%
once the diameter = 7 cm.
◼It may be Ant. (20%) into the
free peritoneal cavity causing
severe shock and death very
early.
◼Post. (80%) with formation of
RP –haematoma -causing
severe back pain, hypotension,
shock, absence of femoral
pulses & a palpable mass -abd.
◼Immediate diagnosis by
US / CT scan.
◼Resuscitation.
◼Massive blood
transfusions (10-15
bottles).
◼Emergency surgery is the
only life-saving procedure
in these cases.

29. ◼Peripheral aneurysms are less
commoncompared to aortic aneurysms.
◼Peripheral aneurysms occur in
descending order of frequency in
popliteal, femoral, subclavian, axillary
and carotid arteries.
◼Symptoms are similarto that of
aneurysm.
◼Duplex scan, DSA, are needed.
◼Treatmentis open repair using arterial
graft (or) endovascular stenting.
Peripheral Aneurysms

30. A V F
Prof. U.Murali.

31. ARTERIO-VENOUS FISTULA (AVF)
•It is an abnormalcommunication
between an artery & vein.
Types –

32. CONGENITAL
•Limbs –part / whole
•Lungs
•Brain
•Others –Bowel / Liver
ACQUIRED
•Trauma –RTA /
penetrating injury
•After surgical
intervention
•Therapeutic –For Renal
dialysis –Cimino fistula
SITES CAUSES

33. STRUCTURAL
•Lengthened
•Warm
•↑ in Girth
•Dilated
•Tortuous
•Thick walled
•Occ. Bone erosion
PHYSIOLOGICAL
•↑ Cardiac output
•L V enlargement
•Cardiac failure
CHANGES CHANGES

34. A V F –CHANGES AT THE LEVEL
•Blood flows –A → V ≈ Diversionof
blood.
•Formation of fibrous sac –aneurysmal
sac between A & V.
•Presents–warm, pulsatile, smooth, soft
& compressible swelling at the site.
•Produce–continuous thrill & continuous
machinery murmur.

35. A V F –CHANGES PROXIMAL
•Pressure applied–A → proximally
-Swelling reduces in size
-Thrill & bruit will disappear
-P R & P Pwill become normal
Nicoladoni’ssign / Branham’s sign.

36. A V F –CHANGES BELOW THE LEVEL
•Due to ↑ –blood flow →
-Lengthened
-↑ in Girth
-Warm
•Arterialization of veins –V I
-Dilated & tortuous veins.

37. A V F -INVESTIGATIONS
•Angiogram –M R A
•Doppler study
•X-ray part
•E C G
•E C H O

38. A V F –CONGENITAL –TREATMENT
•Conservative–Sclerotherapy.
•Surgical ligation –Feeding vessels
& complete excision of the lesion.
•Therapeutic embolization.
•In emergency –torrential bleeding
Amputation is the final option.

39. A V F –ACQUIRED–TREATMENT
•Early stages –Excision with
reconstruction –A & V –Venous /
Dacron graft.
•Emergency–Quadruple ligation –both
A & V above & below the fistula are
ligated.
•Therapeutic embolizationcan be tried.

40. To Summarize
◼Types & Causesof aneurysm.
◼C/F, Complications & Management of aneurysm.
◼Etiopathology & C/F of AAA.
◼Complications & D/D of Abdominal Aortic Aneurysm.
◼Investigations & Treatment methods of symptomatic AAA.
◼AVF –Causes, changes at various levels & management.

41. References

42. Question Time
◼Define Aneurysm. List the types & causes of aneurysm.
◼Outline the complications & treatment of aneurysm.
◼Enumerate the causes of AAA and classify them.
◼List the complications & D/D of Abdominal Aortic Aneurysm.
◼Explain the C/F and treatment methods of symptomatic (without rupture)
AAA.
◼Mention the structural & physiological changes of AVF.
◼Identify the changes at, proximal & below the level of AVF.

43. Physiological effects of a large AV fistula include
all of the following, except–
◼a)Increase in cardiac output.
◼b)Decrease in pulse pressure.
◼c)Overgrowth of limbs.
◼d)Tachycardia.

44. Most common site of peripheral aneurysms is –
◼a)Femoral artery.
◼b)Radial artery.
◼c)Popliteal artery.
◼d)Brachial artery.

45. Most aneurysms of the abdominal aorta are
located at –
◼a)Proximal to the origin of celiac axis.
◼b)At or near the celiac axis but proximal to the origin of the SMA.
◼c)At or near the SMA, but proximal to the origin of the RA.
◼d)Distal to the origin of the renal arteries.

46. All of the following are correct regarding AV
fistula, except–
◼a)Arterialization of the veins.
◼b)Proximal compression causes increase in heart rate.
◼c)Localized gigantism.
◼d)Causes LV enlargement and cardiac failure.

47. A patient, during a routine health check, is discovered
to have an AAA. He has no symptoms due to it. The
aneurysm should be operated electively if –
◼a)It is 2 to 4 cm in size.
◼b)It is 5 to 7 cm in size, but not if it 2 to 4 cm.
◼c)Should not be operated regardless of size, since it is
asymptomatic.
◼d)Should be operated regardless of size, for fear of rupture.

48. ◼