VASCULAR PATHOLOGY

2. 2
CONTENTS
1. DEFINATION
2. ETIOLOGY
3. CLASSIFICATION
4. PATHOGENESIS
5. MORPHOLOGICAL FEATURES
6. COMPLICATIONS
7. TREATMENT
8. MANAGEMENT

3. 3
• Is the congenital or acquired abnormal, localized, irreversible
dilation of any part of CVS(blood vessels or heart)
• Most commonly involve large elastic arteries, especially the aorta and
its major branches.
Complications:
1. Thrombosis
2. Embolism
3. Infection
4. Alteration in BF
5. Rupture & hemorrhage
6. Compression of neighboring structures.

4. 4
Caused by weakened vessel wall d/t:
1. Congenital defect;
Marfan's syndrome (fibrillin defect)
Ehlers-Danlos syndrome (collagen defect)
2. Atherosclerosis
3. Systemic disease (HTN)
4. Infection
5. Vasculitis
6. Trauma to the wall
7. Cystic medial degeneration

5. 5
A. Depending upon the composition of the wall:
1. True aneurysm composed of all the layers of
a normal vessel wall.
2. False aneurysm having fibrous wall and
occurring often from trauma to the vessel.
B. Depending upon the shape:
1. Saccular having large spherical out
pouching.
2. Fusiform having slow spindle-shaped
dilatation.
3. Cylindrical with a continuous parallel
dilatation.
4. Serpentine or varicose which has tortuous
dilatation of the vessel.
5. Racemose or circoid having mass of
intercommunicating small arteries and veins.
C. Based on pathogenetic mechanisms:
1. Atherosclerotic (arteriosclerotic)
aneurysms are the most common type.
2. Syphilitic (luetic) aneurysms found in the
tertiary stage of the syphilis.
3. Dissecting aneurysms (Dissecting
hematoma) in which the blood enters the
separated or dissected wall of the vessel.
4. Mycotic aneurysms which result from
weakening of the arterial wall by microbial
infection.
5. Berry aneurysms which are small
dilatations especially affecting the circle of
Willis in the base of the brain.
Only three common types of aortic aneurysms—
atherosclerotic, syphilitic and dissecting, will be
described

6. 6
Fibrous wall

7. 7
• Most common form of aortic aneurysms.
• Male, 50 years old
• Most common in the abdominal aorta
• All forms of aneurysms of abdominal aorta (fusiform, cylindrical and saccular)
should be considered atherosclerotic until proved otherwise.
• Other locations include thoracic aorta (essentially the ascending part and arch of
aorta), iliac arteries and other large systemic arteries.
Symptoms
• Asymptomatic initially
• Pulsatile mass
• Mid-abdominal to lower back pain
Signs
• Abdominal bruit on auscultation (50%)

8. 8
• Severe atherosclerotic lesions is the basic problem which cause thinning and
destruction of the medial elastic tissue resulting in atrophy and weakening of the
wall.
• Since atherosclerotic lesions are most common and severe in the abdominal aorta,
atherosclerotic aneurysms occur most frequently here.
• In the thoracic aorta, besides atherosclerotic lesions, medial degeneration is
another additional factor implicated in pathogenesis.

9. 9
Abdominal aorta types are most frequently infrarenal, above the
bifurcation of the aorta but may extend into common iliac arteries.
Often larger than 5-6 cm in diameter (Normal diameter of abdominal
aorta is 2cm)
Most frequently fusiform in shape
The lumen of aneurysm often contains mural thrombus.
Histologically,
Normal arterial wall structure is lost.
Predominance of fibrous tissue in the media and adventitia with mild
chronic inflammatory reaction.
The intima and inner part of the media show remnants of atheromatous
plaques and mural thrombus.

10. 10
1. Rupture
 Is the most serious and fatal
complication.
 Risk of rupture depends upon the size
& duration of the aneurysm & the
BP.
 Rupture of abdominal aneurysm may
occur either into the peritoneum or
into the retroperitoneum resulting in
sudden and massive bleeding.
 Occasionally, there may be slow
progressive leak from the aneurysm.
2. Infection
A ruptured aneurysm is more likely to
get infected.
3. Compression
May press upon some adjacent
structures such as compression of
ureter and erosion on the vertebral
bodies.
4. Arterial occlusion
Atherosclerotic aneurysms of the
abdominal aorta may occlude the
IMA, or there may be development of
occlusive thrombosis.
However, collateral circulation
develops slowly and is nearly always
sufficient so as not to produce effects
of ischemia.
5. Thromboembolism
Is rather common in abdominal
aneurysms.
D/t stasis of blood

11. 11
• Also called luetic aneurysms
• Cardiovascular syphilis occurs in about 10% cases of syphilis.
• It causes arteritis—syphilitic aortitis and cerebral arteritis.
• One of the major complications of syphilitic aortitis is syphilitic or luetic
aneurysm that develops in the tertiary stage of syphilis.
• It usually manifests after age 50.
• More common in men.
• Predominant site of involvement is the thoracic aorta, especially in the
ascending part and arch of aorta.
• May extend proximally into the aortic valve causing aortic incompetence
and may lead to syphilitic heart disease.
• Less often, it may extend distally to involve abdominal aorta.

12. 12
• Immune reaction against vasa vasorum
• Chronic inflammatory cells (plasma cells and lymphocytes) collect around the
vessel causing compression and narrowing of the lumen
• These chronic inflammatory cells also release GFs – causes excessive
proliferation of endothelial cells – further narrowing of the lumen
• Nutritional and oxygen supply to media and adventitia decreased for long
• This causes degenerative changes, inability to withstand pressure and eventually
bulging out

13. 13
Saccular in shape
3-5 cm in diameter.
Fusiform or cylindrical less oftenly.
Tree-bark appearance – intimal wrinkling because of fibrous scars caused by chronic
inflammation
Aortic valve involvement - producing valvular incompetence and LVH d/t volume overload
resulting in massively enlarged heart called ‘cor bovinum’.
Histologically,
Adventitia shows fibrous thickening
Endarteritis obliterans of vasa vasorum.
Fibrous scar tissue may extend into the media and the intima.
Rarely, spirochetes may be demonstrable in syphilitic aneurysm.
Often, mural thrombus is found in the aneurysm.

14. 14
1. Compression
 Trachea - Dyspnea, stridor
 Esophagus - Dysphagia
 Recurrent laryngeal nerve – Hoarseness of voice, brassy cough
 Vertebrae, sternum and ribs – Erosion due to persistent pressure, bony pains
2. Rupture
• Likely to rupture causing massive and fatal hemorrhage into the pleural cavity, pericardial
sac, trachea and esophagus.
3. Coronary ostial stenosis
• Causes IHD
4. Aortic valve regurgitation
5. LVH + LVD = Cor Bovinum (>1000g)

15. 15
• The term dissecting aneurysm is applied for a dissecting hematoma in
which the blood enters the separated (dissected) wall of the vessel and
spreads for varying distance longitudinally.
• The most common site is the aorta and is an acute catastrophic aortic
disease.
• Men in the age range of 50 to 70 years with Hx of HTN.
• In women, may occur during pregnancy.
Symptoms
• Severe tearing pain
Acute onset chest pain; radiates to back; sharp/severe/cutting, well localized
• May compress & obstruct aortic branches (e.g. renal or coronary
arteries)

16. 16
Pathogenesis is explained on the basis of
weakened aortic media.
Conditions causing weakening in the
aortic wall resulting in dissection
include:
Hypertensive state:
About 90% cases of dissecting
aneurysm have HPTN which
predisposes such patients to
degeneration of the media in some
questionable way.
Non-hypertensive cases
Are cases in whom there is some local
or systemic connective tissue disorder.
Include;
1. Marfan’s syndrome;
An AD disease with fibrillin defect; a CT
protein required for elastic tissue formation.
2. Development of cystic medial necrosis of
Erdheim;
Especially in old age.
3. Iatrogenic trauma
During cardiac catheterization or coronary
bypass surgery.
4. Pregnancy,
Increased plasma volume.
5. Ehler-Danlos syndrome (collagen defect)
6. Coarctation of Aorta (wall stress)
Once medial necrosis has occurred, hemodynamic
factors, chiefly HTN, cause tear in the intima and
initiate the dissecting aneurysms.
The media is split at its weakest point by the inflowing
blood.
An alternative suggestion is that the medial hemorrhage
from the vasa vasorum occurs first and the intimal tear
follows it.
Further extension of aneurysm occurs due to entry of
blood into the media through the intimal tear.

17. 17
No significant dilatation, thus called ‘dissecting
hematoma’.
Begins in the arch of aorta.
Sharply-incised, transverse or oblique intimal
tear, 3-4 cm long, most often located in the
ascending part of the aorta.
Dissection between the outer and middle third of
the aortic media
Dissection extends proximally into the aortic valve
ring as well as distally into the abdominal aorta.
Dissection may extend into the branches of aorta
e.g. into the arteries of the neck, coronaries, renal,
mesenteric and iliac arteries.
Dissection may affect the entire circumference
of the aortic media or a segment of it.
A second intimal tear may be seen in the distal
part of the dissection so that the blood enters the
false lumen through the proximal tear and
reenters the true lumen through the distal tear.
If the patient survives, the false lumen may
develop endothelial lining and ‘double-barrel
aorta’ is formed.
Histologically,
Characteristic features of cystic medial necrosis
include:
Focal separation of the fibromuscular and elastic
tissue of the media.
Numerous cystic spaces in the media containing
basophilic ground substance.
Fragmentation of the elastic tissue.
Increased fibrosis of the media.

18. 18

19. 19
I. DeBakey classification.
Depending upon the extent of aortic dissection, three
types are described:
Type I:
Comprises 75% of cases.
Intimal tear begins in the ascending aorta but
dissection extends distally for some distance.
Type II:
Comprises 5% of cases.
Dissection is limited to the ascending aorta.
Type III:
Constitutes the remaining 20% cases.
Intimal tear begins in the descending thoracic
aorta near the origin of subclavian artery and
dissection extends distally.
II. Stanford classification.
Depending upon clinical management, 2 types are
described:
Type A (Proximal dissection):
Involves the ascending aorta
Includes type I and II of DeBakey scheme
because clinical management is the same.
Type B (Distal dissection):
Limited to descending aorta, sparing the
ascending aorta.
It corresponds to DeBakey type III.

20. 20

21. 21
1. Rupture
Hemorrhage from rupture of a dissecting aneurysm in the ascending aorta results in mortality
in 90% of cases.
Most often, hemorrhage occurs into the pericardium; less frequently it may rupture into
thoracic cavity, abdominal cavity or retroperitoneum.
2. Cardiac disease
Involvement of the aortic valve results in aortic incompetence.
Obstruction of coronaries results in ischemia causing fatal MI.
Rarely, dissecting aneurysm may extend into the cardiac chamber.
3. Ischemia
Obstruction of the branches of aorta by dissection results in ischemia of the tissue supplied.
Thus, there may be renal infarction, cerebral ischemia and infarction of the spinal cord.

22. 22
Site
Cerebral artery at bifurcations of Circle of Willis
Anterior communicating artery with ACA
Cause
Congenital (absence of internal elastic lamina &
muscular wall)
Associated with:
 PCKD (10-15%)
 Coarctation of aorta (Increased pressure in
cerebral vessels)
Clinical features
Headache, stiff neck (meningeal irritation) & death
Gross
Saccular, 5-10 mm to > 3 cm; may be multiple
Complication
Rupture→ subarachnoid hemorrhage

23. 23
Historically, Tx of arterial aneurysms has been limited to either surgical
intervention or watchful waiting, with control of BP.
Endovascular or minimally invasive techniques have been developed for many
types of aneurysms.
Intracranial aneurysms
• Two treatment options for brain aneurysms exists:
 Surgical clipping
 Endovascular coiling.
Surgical clipping
 Was introduced by Walter Dandy of the Johns Hopkins Hospital in
1937.
 Consists of a craniotomy to expose the aneurysm and closing the
base or neck of the aneurysm with a clip
Endovascular coiling
 Was introduced by Guido Guglielmi at UCLA in 1991.
 Consists of passing a catheter into the femoral artery in the groin,
through the aorta, into the brain arteries, and finally into the
aneurysm itself.
 Platinum coils initiate a clotting reaction within the aneurysm that, if
successful fill the aneurysm dome and prevent its rupture.
Aortic and peripheral aneurysms
• For aneurysms in the aorta, arms, legs, or head, the weakened
section of the vessel may be replaced by a bypass graft that is
sutured at the vascular stumps.
• Instead of sewing, the graft tube ends, made rigid and expandable
by nitinol wireframe, can be easily inserted in its reduced
diameter into the vascular stumps and then expanded up to the
most appropriate diameter and permanently fixed there by external
ligature.
• New devices have been developed to substitute the external
ligature by expandable ring allowing use in acute ascending aorta
dissection, providing airtight easy and quick anastomosis
extended to the arch concavity
• Less invasive endovascular techniques allow covered metallic
stent grafts to be inserted through the arteries of the leg and
deployed across the aneurysm.
Renal aneurysms
• Very rare consisting of only 0.1 0.09%; rupture is even more rare.
• Conservative Tx with control of concomitant HPTN being the
primary option with aneurysms smaller than 3 cm.
• If symptoms occur, or enlargement of the aneurysm, then
endovascular or open repair should be considered
• Pregnant women d/t high rupture risk of up to 80% should be
treated surgically.

24. 24
• Smoking Cessation- Single most important modifiable risk factor
• Exercise Therapy- Evidence suggests may benefit small aneurysms
• Beta Blockers- May decrease the rate of expansion? Important cardiovascular
effects thus use advocated.
• ACE inhibitors- Evidence is mixed, however, implicated in less aneurysm
rupture.
• Doxycycline
Antibiotic activity against chlamydia species
Suppresses expression of MMP
• Statins- associated with reduced aneurysm expansion rates. Decreases MMP-9 in
aneurysm wall.