Aortic Aneurysm

Definitions

• True aneurysm (involves all 3 layers of aorta) vs. false (rupture contained in adventitia)

• Location: root (annuloaortic ectasia), thoracic (TAA). thoracoabdominal, abdominal

• Type: fusiform (circumferential dilation) vs. saccular (localized dilation) Epidemiology (Ore 2005:111*1«; La«« 2005:365:1577)

• TAA: usually involves root/ascending Ao or descending Ao (arch & thoracoabd rare)

Risk factors: connective tissue diseases (Marfan. Ehler s-Dantos type IV). congenital disorders (bicuspid Ao'VTurner s); HTN atherosclerosis: aortitis (Takayasus. GCA. spondyloarthropathies, syphilis); familial: chronic Ao dissection; trauma

• Abdominal aortic aneurysm (AAA): prev. 5% among individuals -65 y

5-10* more common in men than women; most infrarenal

Risk factors risk factors for atherosclerosis: smoking. HTN. hyperlipidemia. age. FHx

Pathophysiology

• TAA: cystic medial necrosis

• AAA: atherosclerosis & inflammation matrix degeneration medial weakening

• Inflammatory and infectious/mycotic aneurysms rare

Screening

• TAA: no established guidelines

• AAA: / for pulsatile abdominal mass in all Pts; U/S for all men -60 y w/ FHx of AAA

and all men 65-75 y w/ prior tobacco use (lone« 2002:360:1531;Annob 2005:142:203)

Diagnostic studies (On 2005:111:816)

• CXR: often abnormal, but not definitive in TAA

• Ultrasound: screening and surveillance test of choice for AAA

• Contrast CT: quick, noninvasive, good Se & Sp for all aortic aneurysms

• MRI: preferred for aortic root imaging for TAA. but also useful in AAA

• TTE/TEE: useful for root and rest of TAA

Treatment (JACC 2006:47:1)

• Risk factor modification: smoking cessation. I cholesterol

(i-blockers (A dP/dt) i aneurysm growth (NEJM 1994:330133s;JVosc Surg 2002:35:72) ACEI assoc. w/ I risk of rupture (Lancet 2006:368:659) no burst activity/exercise requiring Valsalva maneuvers

TAA: growing > 1 cm/y, ascending -5.5 cm; descending >6 cm; Marfan Pt -4.5-5 cm.

aneurysm -4 cm and planned AoV surgery AAA: rapidly growing, infrarenal/juxtarenal -5.5 cm (nejm 2002:346:1437.1445)

• Endovascular repair (Ore 2005.112:1663): guidelines evolving; consider for high-risk Pts i AAA mort.. but t complic. and no a in overall mort. c/w surgery <evar i. lancet 2005:365 2179: dream, nejm 2005.3512398); no advantage over medical Rx in Pts unfit for surgery (evar 2.Lancet 2005:365:2187)

Complications

• Pain: gnawing chest, back, or abdominal

• Rupture: risk t w/ diameter, female sex. current smoking, HTN

TAA 2.5%/y if <6 cm vs. 7% if >6 cm: AAA: 1%/y if <5 cm vs. 6.5% if 5-5.9 cm may be heralded by t pain; once occurs, usually fatal or Pt may p/w severe constant pain and in hemorrhagic shock; 90% mortality

• Aortic Dissection (see following)

• Thromboembolic ischemic events

• Compression of adjacent structures (eg. SVC. trachea, esophagus) Follow-up

• Expansion rate - 0.1 cm/y for TAA. 0.4 cm/y for AAA

• Serial imaging first 3.6.9. & 12 mos. then annually

• Screening for CAD. PAD. and aneurysms elsewhere, espec. popliteal. 25% of Pts w/

TAA will also have AAA.

Was this article helpful?

0 0

Post a comment