Definition
A.An aortic aneurysm is an abnormal enlargement or bulging of the wall of the aorta.
B.An aneurysm can occur anywhere in the vascular tree.
C.The bulge or ballooning may be defined as a:
1.Fusiform: Uniform in shape, appearing equally along an extended section and edges of the aorta.
2.Saccular aneurysm: Small, lopsided blister on one side of the aorta that forms in a weakened area of the aorta wall.
D.An aneurysm can develop anywhere along the aorta.
1.Abdominal aortic aneurysms (AAAs): Occur in the section of the aorta that runs through the abdomen (abdominal aorta).
2.Thoracic aortic aneurysms: Occur in the chest area and can involve the aortic root, ascending aorta, aortic arch, or descending aorta.
3.Thoracoabdominal aortic aneurysms: Involve the aorta as it flows through both the abdomen and chest.
Incidence
A.Approximately three to four per 100,000 per year.
1.Intraperitoneal rupture (20%).
2.Retroperitoneal rupture (80%).
3.Aortocaval fistula (3%–4%).
4.Primary aortoduodenal fistula (less than 1%).
Pathogenesis
A.Once the aorta reaches a critical diameter (about 6 cm in the ascending aorta and 7 cm in the descending aorta), it loses all distensibility, so that a rise in blood pressure to around 200 mmHg (as can occur physiologically during stress or exertion) can exceed the arterial wall strength and may trigger dissection or rupture. This is an emergency that warrants immediate intervention; often surgical.
B.Often occurs as:
1.Retroperitoneal leak or rupture: If blood leaks into the space around the aorta behind the gut cavity then the leak is contained
by the tissues and the patient is more likely to survive long enough to get to the hospital.
2.Free intraperitoneal rupture: If the rupture is into the gut cavity (the peritoneal cavity) then there are no tissues to contain
the escape of blood from the aorta, and it is much less likely that the patient will survive long enough to be taken to the hospital. Virtually all the blood in the circulation can escape into the peritoneal cavity.
Predisposing Factors
A.Genetic: Familial thoracic aortic aneurysm and dissection (TAAD).
B.Connective tissue disorders (Marfan’s syndrome, Ehlers–Danlos syndrome type IV, and Loeys–Dietz syndrome, which partly resembles Marfan’s syndrome).
C.Aortitis from giant cell arteritis.
D.Rheumatoid arthritis.
E.Behçet’s disease.
F.Takayasu’s arteritis or retroperitoneal fibrosis.
G.Infection, such as syphilis and HIV.
H.Trauma.
I.Weightlifting.
J.Cocaine and amphetamine use.
Subjective Data
A.Common complaints/symptoms.
1.Most people are unaware that they have an aneurysm because, in most cases, there are no symptoms. However, as aneurysms grow, symptoms may include:
a.Pulsating enlargement or tender mass felt by a physician when performing a physical examination.
b.Pain in the back, abdomen, or groin that may be prolonged and not relieved with position change or pain medication.
2.A ruptured aneurysm usually produces sudden, severe pain and other symptoms, such as loss of consciousness or shock, depending on the location of the aneurysm and the amount of bleeding.
B.Common/typical scenario.
1.Thoracic aneurysm dissection rupture.
a.TAAs are easily missed or misdiagnosed for cardiac ischemia.
b.Patients complain of sudden intense and persistent chest or back pain, pain that radiates to the back, trouble breathing, low blood pressure causing feelings of fainting, loss of consciousness, and trouble swallowing.
2.Abdominal aneurysm dissection or rupture.
a.With AAA rupture patients complain of a sudden onset of severe lower back pain that may radiate to the groin, hypotension, or transient lower limb paralysis.
b.Classic triad of symptoms: Pain, hypotension, and a pulsatile mass.
c.Most abdominal aneurysms rupture into the retroperitoneal cavity.
d.Rarely, AAA may rupture into the abdominal veins or the bowel. This may or may not be associated with retroperitoneal rupture.
e.Emergent surgery is warranted once diagnosis is confirmed with echocardiogram, CT scan, or MRI.
f.Rupture of an aneurysm is one of the most fatal surgical emergencies, with an overall mortality rate of 90%.
C.Family/social history.
1.Family history is an independent risk factor for more rapid growth of aortic aneurysms and should be assessed.
2.First-degree family history of aortic aneurysm or bicuspid aortic valve also elevates risk.
3.Ask about smoking, which also increases risk of aortic aneurysm.
D.Review of systems.
1.HEENT: Ask about any hoarseness or difficulty swallowing.
2.Respiratory: Ask if the patient is having any shortness of breath, coughing, difficulty breathing, or chest pain.
3.Musculoskeletal: Ask about back pain.
Physical Examination
A.Transient lower limb paralysis.
B.Right hypochondrial pain.
C.Nephroureterolithiasis.
D.Groin pain.
E.Testicular pain.
F.Testicular ecchymosis (blue scrotum sign of Bryant).
G.Iliofemoral venous thrombosis.
H.Inguinoscrotal mass mimicking a hernia.
I.Patient may show decreased red blood cell (RBC) or hemoglobin due to internal blood loss and increased white blood cell (WBC).
Diagnostic Tests
A.An echocardiogram, MRI, or CT scan may help to differentiate the diagnosis.
1.Echocardiogram.
2.CT and MRI only if the aorta is calcified.
B.Aortic angiogram or arteriogram: An arteriogram or angiogram accurately and directly depicts the vasculature; therefore, it clearly delineates the vessels and any abnormalities.
1.An abdominal aneurysm would only be visible on an x-ray if it were calcified.
2.CT scan and ultrasound don’t give a direct view of the vessels and don’t yield as accurate a diagnosis as the arteriogram.
Differential Diagnosis
A.Acute gastritis.
B.Appendicitis.
C.Urinary tract infection (UTI).
D.Diverticulitis.
E.Pancreatitis.
F.Cholelithiasis.
G.Small bowel obstruction.
H.Myocardial infarction.
Evaluation and Management Plan
A.General plan.
1.Uncomplicated aneurysm.
a.The goals of treatment include:
i.Preventing the aneurysm from growing.
ii.Preventing or reversing damage to other body structures.
iii.Preventing or treating a rupture or dissection.
iv.Allowing the patient to continue doing normal daily activities.
v.Follow-up and screening for risk to prevent occurrence, which is key.
vi.Evaluation of risk factors.
b.Primary management is rigorous blood pressure control.
c.Smoking cessation.
d.Antiplatelet therapy where appropriate.
B.Dissecting or ruptured aneurysm.
1.Rupture of aneurysm is an emergency: Patient is often in shock and needs immediate intervention.
a.Open repair when a rupture occurs as an emergency surgery.
b.Emergency endovascular repair for ruptured AAA, thanks to new technology, is now feasible?
c.Operative risk is based on patients’ comorbidities and hospital factors (Table 11.1).
2.Type of repair.
a.Open repair of an AAA involves an incision of the abdomen to directly visualize the aortic aneurysm.
b.Endovascular aneurysm repair (EVAR).
C.Patient/family teaching points.
1.Patients should seek attention if they feel chest pain or they just suddenly don’t feel right.
2.A strong pulse sensation near the navel or bulge from the abdomen is also a reason to contact a provider right away. Deep constant or severe back or flank pain may be the only symptom a patient has of an expanding aneurysm.
D.Pharmacotherapy.
1.Uncomplicated aneurysm.
a.Statins: The role of statin therapy in AAA is unproven, but statins are advised because AAA patients have increased cardiovascular disease (CVD) risk.
b.Other medical treatment: There is some evidence that the following may reduce the rate of expansion of small aneurysms, but their role is not yet clear.
i.Doxycycline or roxithromycin.
ii.Angiotensin-converting enzyme (ACE) inhi-bitors or losartan.
iii.Statins.
iv.Low-dose aspirin.
v.Evaluate annually for risk of rupture, and follow-up.
E.Discharge instructions.
1.Patients with incidentally discovered AAA should be taught to recognize signs and symptoms of an emergency and be given instructions on what to do next.
2.Patients who undergo surgery should be taught effective wound care and to assess for signs and symptoms of healing.
Follow-Up
A.Surgical intervention for aneurysm (abdominal or thoracic).
1.Patients with an incidentally discovered AAA that is less than 3 cm in diameter require no further follow-up.
2.With AAAs 4 to 5 cm in diameter, elective repair may be of benefit for patients who are young,