An aortic aneurysm is a localized sac or dilation formed at a weak point in the aortic wall. They most commonly occur in the abdominal aorta and can be caused by conditions like hypertension, atherosclerosis, and smoking. Aortic aneurysms are classified as either saccular or fusiform based on their shape and size. Untreated aneurysms risk rupture, which can cause massive hemorrhage and death. Surgical treatment involves replacing the diseased aortic segment with a synthetic graft to prevent rupture.
2. ANEURYSMS
An aneurysm is a localized sac or dilation formed at a weak
point in the wall of the aorta.
Aortic aneurysm may involve the aortic arch, thoracic aorta
and or abdominal aorta.
most aneurysms however are found in the abdominal
aorta below the level of the renal arteries.
8. True aneurysm:
When an aneurysm involves all three layers of the
arterial wall (intima, media, and adventitia) or
the attenuated wall of the heart.
Further divided according to the shape and size
into :
1.Saccular aneurysms.
2.Fusiform aneurysms.
10. cont…
2.Fusiform aneurysms:
Involve diffuse, circumferential dilation of a long
vascular segment.
Vary in diameter (≤20 cm) and in length and can
involve extensive portions of the aortic arch,
abdominal aorta, or even the iliacs.
11.
12. Cont…
• A false aneurysm or pseudoaneurysm, is not an aneusysm but a
disruption of all layers of the arterial wall resulting in bleeding that is
contained by surrounding structure. false aneurysms may result from
trauma or infection or occur after peripherial arteries bypass graft
surgery at the site of the graft to artery anastomosis they also may
result from arterial leakage after removal of cannulae such as upper
or lower extremity arterial catheters and intra aortic balloon pump
devices.
14. Cont…
5. Mycotic aneurysms can originate:
(a) From embolization of a septic thrombus, usually as a
complication of infective endocarditis.
(b) As an extension of an adjacent suppurative process.
(c) By circulating organisms directly infecting the arterial
wall.
15. Abdominal Aortic Aneurysm:
Atherosclerosis, the most common cause.
It causes thinning and weakening of the media secondary to
intimal plaques.
Such plaques compress the underlying media.
The media consequently undergoes degeneration and
necrosis.
Most frequently in the abdominal aorta (abdominal aortic
aneurysm AAA)
16. Clinical Course
The clinical consequences of AAA include:
1. Rupture into the peritoneal cavity or retroperitoneal
tissues with massive, potentially fatal hemorrhage
2.Obstruction of a branch vessel resulting in downstream
tissue ischemic injury.
17. Cont…
The risk of rupture is directly related to the size of the
aneurysm.
Timely surgery is critical; operative mortality for
unruptured aneurysms is approximately 5%,
whereas emergency surgery after rupture carries a
mortality rate of more than 50%.
18. Thoracic aortic aneurysms
(1) Encroachment on mediastinal structures.
(2) Respiratory difficulties caused by encroachment on the lungs and
airways.
(3) Difficulty in swallowing caused by compression of the esophagus
(4) Persistent cough from irritation of the recurrent laryngeal nerves.
(5) Pain caused by erosion of bone (i.e., ribs and vertebral bodies).
(6) Cardiac disease due to valvular insufficiency.
(7) Aortic rupture.
19. Diagnostic studies
• Chest X-Ray are useful in demonstrating the mediastinal
silhouette and any abnormal widening of the thoracic aorta.
• Plain X-Ray of the abdomen may show calcification within the
wall of abdominal aorta aneurysms
• Electrocardiogram (ECG)may be performed to rule out evidence
of myocardial infarction (MI) because some person with thoracic
aneurysms have symptoms suggestive of angina.
Echocardiography assists in the diagnosis of aortic valve
insufficiency related to ascending aortic dilation.
20. Cont…
• Ultrasonography is useful in screening for aneurysms and to
serially monitor aneurysm size.
• CT scan is the most accurate test to determine the anterior
to posterior length the cross sectional diameter and the
presence of thrombus in the aneurysm.
• Magnetic resonance imaging (MRI) also may be used to
diagnose and assess the location and severity of aneurysms.
21. Management
The goal of management is to prevent the aneurysm from
rupturing. therefore early detection and prompt treatment is
imperative.
• once an aneurysm is suspected studies are performed to
determine its exact size and location a careful review of all
body system is necessary to identify any coexisting disorder
especially of the lungs heart or kidney because they may
influence the patient’s surgical risk if carotid and /or coronary
artery obstructions are present they may need to be
corrected before the aneurysm is repaired for individual with
small aneurysms(<4cm).
22. Cont…
• conservative therapy typically is initiated which consist
of risk factor modification, decreasing blood pressure
(BP) and monitoring aneurysm size every 6 month using
ultrasound MRI or CT scan if the aneurysm size more
than 5.5cm or the increase in aneurysm size more than
0.5cm in 6 month should be repaired surgically.
23. Surgical management
The surgical technique involve
• Incising the deased segment of the aorta ;
• Removing intraluminal thrombus or plaque;
• Inserting synthetic graft dacron or polytetrafluoroethylene
(ptfe),which is sutured to the normal aorta oroximal and
distal to the aneurysm
24. Conventional surgical repair
• Suturing the native aortic wall around the graft so that it will
act a protective cover. if the iliac arteries also are aneurysmal,
the entire diseased segment is replaced with a bifurcation
graft. With saccular aneurysms. It may be possible to excise
only the bulbous lesion, repairing the artery by primary
closure (suturing the artery together) or by application of an
autogenous or synthetic patch graft over the arterial defect.
25. Cont…
• All aaa resections require cross clamping of the aorta
proximal and distal to the aneurysm.
• Most resections can be completed in 30 to 45 minutes, after
which time the clamps are removed and blood flow to the
lower extremities is restored.
• If the aaa extends above the renal arteries or if the cross
clamp must be applied above the renal arteries, adequate
renal perfusion
26. Complications
The most serous complication related to an untreated
aneurysm is rupture if rupture occure posteriorly into the
retroperitoneal space bleeding may be temponaded by
surrounding structure preventing exsanguinations and death
in this case the patient often sever back pain and may or
may not have back or flank ecchymosis (Grey turner’ssign)
27. Complications
• If rupture occurs anteriorly into the abdominal cavity most patient do
not servive long enough to get to the hospital they die from massive
hemorrhage if the patient does reach the hospital, he or she is in
hypovolemic shock with tachycardia hypotension pale clammy skin
decreased urine output altered level of consciousness and abdominal
tenderness on palpation in this situation simultaneous resuscitation
and immediate surgical repair are necessary.
