Aortic Aneurysms Flashcards
AA Def.
Outpouching or dilation of arterial wall
¼ in thoracic aorta (TAA) and ¾ in abdominal aorta (AAA) – most occur below renal arteries
Larger aneurysm = greater risk of rupture
Etiology and Patho
Dilated aortic wall becomes lined with thrombi that can embolize
Leads to acute ischemic symptoms in distal branches
Causes
Degenerative (atherosclerosis – wall becomes weakened from buildup of plaque) Congenital Mechanical Penetrating or blunt trauma Inflammatory Infectious (HIV, chlamydia)
Risk Factors
Men > women White > African Americans Increased incidence with age HTN CAD Family history Tobacco use: biggest modifiable Obesity High cholesterol Lower extremity PAD Carotid artery disease Previous stroke
Genetic link is related to a number of congenital anomalies
True Aortic Aneurysm
walls of artery forms aneurysm; at least one vessel layer still intact
Fusiform AA
circumferential, relatively uniform in shape
Saccular AA
pouchlike with narrow neck connecting bulge to one side of arterial wall
False (pseudoaneurysm)
not an aneurysm, a disruption of all layers of arterial wall which results in bleeding contained by surrounding structures (clot)
Thoracic Aorta Aneurysm Mainfestations
Often asymptomatic Most common manifestations: deep diffuse chest pain, may extend to interscapular area Ascending aorta/aortic arch Angina TIAs Coughing and SOB Hoarseness and/or dysphagia Distended neck veins; edema of face and arms (pressure on superior vena cava)
Abdominal Aortic Aneurysm Manifestations
Often asymptomatic
Frequently detected:
On routine physical exam
When patient examined for unrelated problem (i.e., CT scan, abdominal x-ray)
May mimic pain associated with abdominal or back disorders
Aorta is widening, compressing on surrounding structures: may cause back pain, epigastric discomfort, altered bowel elimination, intermittent claudication
May spontaneously embolize plaque
Causing “blue toe syndrome” = blood flow but small blood clots on side of aorta fill small capillaries in periphery
Complications of AA
Rupture
Rupture into retroperitoneal space (ruptures toward back)
Bleeding may be tamponaded by surrounding structures, thus preventing exsanguination and death
Severe back pain
May/may not have back/flank ecchymosis (Grey Turner’s sign)
Rupture into thoracic or abdominal cavity
Not many structures there
Massive hemorrhage
Most do not survive long enough to get to the hospital
Diagnostics
X-rays: may show widened aorta
ECG – if mild diffuse chest pain, rule out MI
Echocardiogram: assist in diagnosis of aortic valve insufficiency
US: screen for aneurysms, monitor size over time
Angiography: not reliable for determining diameter/length, but can provide info about involvement of other vessels
CT scan: most accurate test
MRI: diagnose and assess location and severity
Small aneurysm (4-5.4 cm)
Conservative therapy used
Risk factor modification: tobacco cessation, decrease BP
US, MRI, CT: monitoring every 6-12m
5.5 cm = threshold for repair
Intervention at > 5cm in women with AAA
Surgical intervention may occur earlier in: patients with a genetic disorder, rapidly expanding aneurysm (MVA), symptomatic patients, high rupture risk
AAA resections
Requires cross-clamping of aorta proximal and distal to aneurysm
Can be completed in 30-45m
Clamps are removed and blood flow to lower extremities is restored
If extends above renal arteries or if cross-clamp must be applied above renal arteries 🡪 risk of post-op renal complications is increased significantly
